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Tracking and tracing to the root cause: case studies in microbial contamination

Posted: 11 April 2022 | Tim Sandle (Bio Products Laboratory) | 2 comments

In this article, pharmaceutical microbiologist and contamination control expert Tim Sandle presents three microbial contamination investigation case studies, highlighting the key lessons for pharmaceutical microbiologists to take away and the underlying importance of identifying the root cause of microbial data deviations.

Introduction

One of the main activities of the pharmaceutical microbiologist is with determining the contamination control strategy and proactively identifying measures to lower identified risks and, where risks remain of concern, to introduce monitoring. However, there will invariably be microbial recovery, from product (intermediate and finished), from water, cleanrooms and other utilities. A common term of these events is ‘microbial data deviations’, although other terminology can apply. 1 These microbial events require investigation and the importance of such an investigation is elevated where there is recurrence. While investigations are referred to in regulatory documents, there is a dearth of case studies to help guide microbiologists and Quality Assurance departments. This article presents three case studies. While the specific issues may or may not be of direct relevance, the areas examined and the thought processes will be of wider applicability.

Microbial investigations

Microbial data deviations can be categorised as:

• Out of limits results (OOL), which is often applied to environmental monitoring
• Out of specification results (OOS), which is typically used for pharmacopeia tests
• Out of trend (OOT), as defined in relation to a trend chart.

Microbial data deviations need to form part of the quality system and they require an investigation. The target time for microbiology investigations is to be completed within thirty days, against a procedure.

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The optimal way to gather evidence is to visit the area, where the role of the pharmaceutical microbiologist is mostly in the process area. 2 In addition, operators may need to be interviewed and the information should be captured and documented. A further important source of information can be the batch manufacturing or batch processing record. Visits and document reviews can be supported by additional sampling. With sampling, it is best practice to have a hypothesis developed in advance together with the numbers and types of samples detailed. More than one sampling session may be required to account for the variances with microbial distribution. 3 Further evidence should be gathered from accurate microbial species identification.

The three case studies draw on these essential elements and demonstrate how things can sometimes go wrong.

Case study 1: Microbial contamination in non-sterile manufacturing

The first scenario relates to tablet manufacture. The company in question noted repeated finished product failures with a Bacillus species, human skin commensals and Gram-negative rods. Individual tablets had a bioburden estimated to be more than 2,500 colony forming units (CFU), containing the mixed flora.

There was no obvious pattern in relation to the contamination, which was found throughout the batch. Further examinations indicated that multiple batches were found to be contaminated. The important starting point was to undertake microbial identifications to species level, as understanding the microorganisms can provide clues as to the habitat and possible origin. The pattern of different microorganisms also helps with comparing microorganisms isolated in the finished product with organisms recovered from other sources, such as water and the cleanroom, and to track contamination at different points in the process.

The main part of the investigation required a construction of a process flow chart, to enable the manufacturing process to be examined.

Figure 1 : General steps for tablet manufacturing.

The main manufacturing steps, together with initial observations, were:

• Wet mixing of raw materials – this is performed with purified water. The successful mixing of the powder is more difficult than mixing liquid and is based on achieving homogeneity. The ease of this is dependent upon the inherent cohesiveness and resistance to movement between the individual particles.
• Drying – with drying, it is important to keep the residual moisture low enough to prevent product deterioration and ensure free flowing properties. The drying process was found to leave the product as a cake with a high level of residual humidity within it.
• Bulking up – the bulking up process allowed multiple cakes to be transported to the tanks and added via a vacuum lance.
• Compression – compression was believed by the company to be antimicrobial. This was based on development work that provided evidence of a multi-log reduction in the microbial population.
• Packing – the packing process was into blisters, taking place within a controlled environment.

In addition, environmental monitoring data was examined. Here it was found that the routine monitoring of the manufacturing room had not recovered anything atypical. As well as the cleanroom, the purified water system had not seen any recent recoveries of microorganisms.

For the next stage of the investigation, the equipment in the manufacturing process was opened up and sampled microbiologically. In addition, testing was undertaken of the raw material, a substance of natural origin that was found to contain a low level of Gram-negative bacteria. It was of interest that these organisms were of the type seen in the failed batches, but the numbers recovered were relatively low. No organisms were recovered at the wet mixing stage.

The investigation proceeded to the drying stage, looking at the room equipment. One area examined, the extract pipework from the dryer, was found to have pools of condensate inside it. Due to a process improvement step, the extract was no longer being used due to the discontinuation of a product line. A previous version of the product used alcohol rather than water as the mixing agent (the extract was a safety precaution to remove the alcohol fumes). Additional testing revealed that the extract condensate was heavily contaminated with Gram-negative bacteria.

For the investigation of the bulking up stage, the operation of the lance was found to be satisfactory. However, increased environmental monitoring was undertaken and the active (volumetric) air samples taken within the lancing area cleanroom recovered a combination of Bacillus species and skin commensals. Other areas examined included:

• The tank – opened up via the main ‘lid’, further inspection was difficult because there was no manway
• The connection from tank wall to tank lid, which formed a lip about 10cm wide. The lip was covered in a old grey This residual powder was heavily contaminated with the microorganisms isolated from the finished tests.
• The lid of the tank, which had evidence of condensate on it.
• The room HEPA inputs – based on the walls (rather than being ceiling mounted, which would be more conventional), with cold filtered air continuously bathed the top of the tank.

With the study of the compression and packing lines, these recovered no microbial bioburden.

A further important element of any microbial investigation is with the trend. This is examined by constructing a trend chart and overlaying historical events. The trend analysis showed that the finished product failures, due to microbial contamination, began appearing after the alcohol containing product was discontinued.

The overall findings demonstrated a set of different failure modes:

• The wet cake enabled the survival of Gram-negative bacteria
• The lance activity pulled human skin and environmental isolates into the tank
• The old air trapped in the tank allowed condensate to form and
• the poor design of the tank retained the condensate, allowing it to hit the joining tank lip.
• The lip allowed contaminated powder to accumulate. The powder provided a nutritive source which facilitated bacteria to grow.

The reason that the issue appeared, and had not been noted previously, was because the discontinued alcohol containing product would have sanitised the filling equipment. In addition, the compression unit would have helped to have eliminated any low-level microorganisms that would have survived the alcohol step. The removal of the alcohol highlighted the poor controls through the process and led to conditions that enabled the proliferation of microorganisms.

Identifying these areas enabled appropriate corrective and preventative actions to be set. In particular, plant modifications and routine cleaning was introduced.

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Case study 2: Environmental monitoring – the unexplained organism

The second case study, relates to a manufacturing operation within a Grade C cleanroom. From an environmental monitoring session, a working height surface contact plate of a conveyor belt recovered a high level of bacteria, with the plate being ‘too numerous to count’ (against an action level of 25 CFU/cm 2 ). As was customary, the isolates were Gram-stained and then a phenotypic identification was performed using a semi-automated commercial system. The predominant isolate was Yersinia pestis . Other isolates were a set of more typical skin biota of the Staphylococcus species.

The laboratory analyst did not question the Y. pestis identification and the importance of the organism was realised by the supervisor. This is a facultative anaerobic organism that can infect humans via the Oriental rat flea, resulting in plague. 4

The supervisor notified site management that ‘plague’ had been detected at the facility and unsurprisingly a state of panic ensued. Among the activities seriously being considered were site evacuation, notification of local authorities and placing everyone in the microbiology department under enforced isolation.

A more experienced microbiologist was called in and began assembling the facts. The microbiologist determined:

• The recovery of ‘bubonic plague’ from a conveyer belt did not make sense
• The environmental monitoring was performed on night shift
• Post incubation, the plate count was also performed on a night shift
• The microbial identification, following subculture, was also performed on night shift
• The supervisory review and subsequent alert of the discovery of plague was communicated on the night

The reason why the identification was most likely to be inaccurate was quickly established by:

• The apparent pestis was growing on the environmental monitoring agar, which was tryptone soya agar (TSA). In practice, pestis is isolated on stained smears of peripheral blood, lymph node specimens or from sputum. Y. pestis will grow as small, non- lactose fermenting colonies on MacConkey agar or Enterobacteriaceae selective agar, like EMB agar. These are supported by rapid microbiology assays. 5
• The particular colony did not look morphologically like a Gram-negative. Although there are limitations with visual identification, the colonial morphology of Gram-negative and Gram-positive bacteria can often be distinctive.
• A repeat microscopic investigation, requested by the experienced microbiologist, of the older original colony showed the presence of endospores, which pestis does not form.

The bacterium was not Y. pestis . The microbiologist established that the errors that led to the misidentification were:

• The original Gram stain was incorrect – a young colony was stained and the outcome was Gram-variable; however, the analyst selected Gram-negative as the outcome
• The incorrect Gram stain led to the selection of the incorrect identification biochemical test kit
• The bacteria still reacted or grew within a particular patter of biochemical wells, providing a pattern that that was closely matched to a database and the most probable result selected by the software. This was indicated to be pestis.

Rather than questioning the oddness of the result, an emotive response from the supervisor led to rapid escalation of the identification result and considerable business disruption.

From a human factors perspective, the night shift is not a popular timeslot for more experienced microbiologists to work, leading to less experienced personnel often being allocated. Furthermore, personnel are often tired and sometimes fatigue adds to the judgement process.

Case study 3: Sterile product out of specification

The third and final case study relates to a sterile active pharmaceutical ingredient (API) facility who manufacture an injectable dry powder. The product is sterile filtered into a pre-sterilised manufacturing line and then turned into a dry powder and offloaded via Grade A isolators.

With one batch, there was a subsequent sterility test failure. This led to the recovery of two different Bacillus species and an OOS investigation. During the first phase of the investigation, there was a second sterility test failure with the same type of product. This batch also recovered the same two Bacillus species, expanding the scope of the investigation.

The investigation was split into two parts: 6 the first looked at laboratory error and the second at the potential for a manufacturing failure (based on the typical first two phases of the OOS process). Across both parts, environmental monitoring was deployed to extensively sample manufacturing cleanroom air and surfaces; laboratory air and surfaces; isolator air and surfaces; and samples were taken from utilities like compressed air, nitrogen, water-for-injection (WFI), purified water, glycol, plant steam, heating ventilation and air conditioning (HVAC) ducting. A few environmental samples were also taken from support areas, such as the warehouses and controlled-non-classified (CNC) areas.

The environmental monitoring looked at the traditional techniques such as contacts and air samples. Some techniques had to be modified in order to allow for the sampling of air systems, glycol lines and high-pressure steam. The focus of the monitoring was less concerned with the numbers of organisms recovered and more with the types of microorganisms recovered, in an attempt to see if the two Bacillus species could be identified.

Many of the environmental monitoring samples recovered Bacillus in numerous places. The internal phenotypic identification system isolated the two specific species from the laboratory samples and one of the species from a production compressed air sample. The organisation concluded the results were a false positive based on finding the isolates in the laboratory, supported by the fact that two species had not been isolated together from the manufacturing plant. This was reported to senior management.

However, the isolates had also been sent away to an external laboratory for genotypic matching. The genotypic test results revealed that although the species of Bacillus were similar, the specific strains of the Bacillus organisms had not been found in the laboratory. In contrast, the species of Bacillus from the compressed air was genetically related and thus the same strain as the contaminant isolated from the two sterility test failures.

The dilemma was that the original phenotypic results had been reported with the point of origin directed to the laboratory, whereas the definitive data was now pointing towards a production related issue (the compressed air). The recommendation was made that the batches needed to be rejected, although the first reporting of the erroneous root cause caused considerable disagreement in senior management circles.

Lessons to be learned?

In terms of what can be drawn from these three case studies, environmental sampling and monitoring is not only about the numbers of organisms recovered; the type of species isolated can help with establishing origins and trending. The species need to be sense checked: isolates thus far only found in marine trenches or on the rim of volcanoes are unlikely to be recovered from cleanrooms. There is also a need, when batch disposition is resting on the identification, to draw on genotyping beyond the more conventional biochemical or proteomic techniques. An additional area where environmental monitoring can be useful is with moving sampling beyond the routine (to demonstrate a cleanroom remains in compliance); it can also serve as a powerful investigative tool to aid a deeper dive into investigations. This may include additional samples or sampling from areas that are not ordinarily assessed.

The case studies outlined are based on real-life events, collected across the pharmaceutical industry by the Pharmaceutical Microbiology Interest Group. 7 In reading such events there may be a sense of ‘this would not happen to me’; however, it is a recurrent criticism from regulatory inspectors that many investigations are not sufficiently thorough or fail to get to the actual root cause. These case studies may provide advice that can be applied to an organisation’s microbial investigation procedure.

About the author

Dr Tim Sandle  has over 25 years’ experience of microbiological research and biopharmaceutical processing. Tim is a member of several editorial boards and has authored 30 books on microbiology, healthcare and pharmaceutical sciences. Tim works for Bio Products Laboratory Limited (BPL) in the UK and is a visiting tutor at both the University of Manchester and UCL.

• McCullough K, Moldenhauer J. (2015) Introduction in Microbial Risk and Investigations. In McCullough, K. and Moldenhauer, J., (Eds) Microbial Risk and Investigations , Parenteral Drug Association (PDA) and Davis Healthcare International (DHI). Bethesda, MD, pp1-10
• Sutton S. (2011) Successful Microbial Investigations, American Pharmaceutical Review , 74 (2): 34-42
• Sandle T. (2014) Data Review and Analysis for Pharmaceutical Microbiology , Microbiology Solutions, UK., pp1-15
• Deng W, Burland V, Plunkett G, et al . (2002) Genome sequence of Yersinia pestis. Journal of Bacteriology . 184 (16): 4601–11
• Chanteau S, Rahalison L, Ralafiarisoa L, et al. (2003) Development and testing of a rapid diagnostic test for bubonic and pneumonic plague. Lancet 361: 211-216
• Sandle T. (2012): Sterility Test Failure Investigations, Journal of GxP Compliance , 16 (1): 1- 10
• Keen D. (2019) Contamination Case Studies, presented at Pharmig Irish Conference, 25th May 2019

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2 responses to “tracking and tracing to the root cause: case studies in microbial contamination”.

What if no root cause/probable cause found in microbial investigation in non-sterile product?

This is very informative, lots of useful information presented here.

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In This Article Expand or collapse the "in this article" section Case Studies in Groundwater Contaminant Fate and Transport

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• Large Programs and Experimental Sites
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• Gasoline Oxygenates: Methyl Tertiary Butyl Ether (MTBE) and Ethanol
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Case Studies in Groundwater Contaminant Fate and Transport by Barbara Bekins LAST REVIEWED: 03 January 2020 LAST MODIFIED: 26 April 2018 DOI: 10.1093/obo/9780199363445-0096

A case study of groundwater contamination is a detailed study of a single site contaminated with a chemical or mixture that is known to be a problem at many sites. The goal of case studies is to provide insights into the physical, chemical, and biological processes controlling migration, natural attenuation, or remediation of common groundwater contaminants. Ideally, processes occurring at a case study site are representative of other sites so that knowledge gained from these intensive studies can be applied at thousands of sites where fewer data are available. Several characteristics of case studies contribute to their value. First, they may have tens to hundreds of monitoring wells, compared to fewer than ten wells at some contaminated sites. Second, some case studies continue for many years or even decades, providing insights into temporal progression of slow processes. Third, analytical methods prohibitively expensive for routine use or under development may be tested at case study sites. Finally, the ongoing characterization typical of case study sites builds a foundation of knowledge that facilitates sophisticated experimental design and testing of new methods. This article is divided into sections based on the contaminant type because the chemical and biological processes required for remediation vary for each contaminant. Most importantly, some contaminants can be biodegraded whereas metals and radionuclides cannot be destroyed but can be immobilized or rendered less toxic. The emphasis is on case studies of natural processes that control the fate and transport of contaminants in groundwater rather than on active remediation methods. The principles learned from these studies may form the basis for design of remedial strategies. The organic contaminants are divided into: petroleum hydrocarbons, fuel oxygenates, coal tar and wastes from manufactured gas plants, and chlorinated solvents. The inorganic contaminants covered are metals and radionuclides, arsenic, and nitrate. Case studies of mixed waste plumes from landfills are also described. Experimental sites where contaminants have been introduced into an aquifer as an emplaced source or a controlled release may not meet the above definition of case studies, but some are included because the overall goal is to impart lessons learned from detailed field studies. It is impossible to cover all case studies in this short format. Conversely, focusing on one or two does not convey the breadth of research results in entire range of case studies. Instead, the strategy is to describe the evolution of knowledge for each contaminant class while providing citations of relevant case studies. Much of the progress in understanding of the fate of contaminants in groundwater is based on laboratory studies; thus whenever possible, papers that included both field and laboratory results have been included among the citations. Two topics of growing importance have not been covered. These are the fate of pharmaceuticals in groundwater and discharge of contaminant plumes to surface water. These topics merit coverage in the future as knowledge grows and case studies increase in number.

The chemical properties of a contaminant and aquifer affect the reactions that occur in a groundwater contaminant plume. For example, some compounds biodegrade only under anaerobic conditions while others require aerobic conditions. A combination of organic and inorganic reactions may contribute to mobilizing or immobilizing contaminants such as arsenic or metals. These concepts are reviewed in NRC 2000 on natural attenuation. A chapter on the scientific basis for natural attenuation includes a basic explanation of reduction and oxidation (redox) reactions followed by a summary of the effect of redox conditions on microbial transformation of each major contaminant class. Inorganic reactions are also covered, including acid-base, redox, precipitation and dissolution, complexation, sorption, hydrolysis, and decay. More than ten case studies illustrate the processes affecting a range of contaminants in groundwater. A compilation of eighty case studies, NRC 2013 covers complex sites where contaminants are resistant to natural degradation and the subsurface is highly heterogeneous or fractured. The role of redox reactions on the fate of contaminants in groundwater and methods for determining redox conditions are described in Christensen, et al. 2000 . A number of review articles cover specific classes of contaminants. Cozzarelli, et al. 2014 provides an overview of the composition, properties, and natural attenuation processes of petroleum fuels and oxygenates. The properties of methyl tertiary butyl ether (MTBE) that contributed to its widespread groundwater contamination and the history of its use are presented in Rosell, et al. 2006 . A review of polycyclic aromatic hydrocarbon (PAH) remediation in soils, Kuppusamy, et al. 2017 notes the most important sources are manufactured gas plants followed by wood treatment sites, which are covered in a case study section of this article. A comprehensive book on natural attenuation of chlorinated solvents and fuels, Wiedemeier, et al. 2007 describes attenuation mechanisms and investigative strategies illustrated with case studies. Adriaens, et al. 2014 covers halogenated hydrocarbons in the environment including other compartments besides groundwater. A review of heavy metal remedial strategies for groundwater, Hashim, et al. 2011 covers speciation and chemistry, concentration limits, and provides citations of case studies. The global distribution of arsenic contamination is summarized in Ravenscroft, et al. 2009 , along with hydrogeochemistry, hydrogeology, and mitigation strategies. Fowler, et al. 2013 compiles global sources of reactive nitrogen to show that over half of the total is anthropogenic from fertilizer and biological fixation by crops. Two reviews of natural attenuation processes in landfill leachate plumes cover conceptual understanding and research developments with illustrations from case studies (see Christensen, et al. 2001 and Bjerg, et al. 2014 , cited under Landfills ).

Adriaens, P., C. Gruden, and M. L. McCormick. 2014. Biogeochemistry of halogenated hydrocarbons. In Treatise on geochemistry . 2d ed. Vol. 11. Edited by H. D. Holland and K. K. Turekian, 511–533. Oxford: Elsevier.

Comprehensive review of sources of halogenated hydrocarbons and reactions in the environment including microbially mediated, surface mediated, and organic matter mediated. Both chlorinated aromatic and aliphatics are included. The scope covers the fates in the atmosphere, as well as soil, groundwater, and sediments. As a result, specific information about groundwater is limited.

Christensen, T. H., P. L. Bjerg, S. A. Banwart, R. Jakobsen, G. Heron, and H. J. Albrechtsen. 2000. Characterization of redox conditions in groundwater contaminant plumes. Journal of Contaminant Hydrology 45.3–4: 165–241.

DOI: 10.1016/s0169-7722(00)00109-1

Provides a short tutorial on redox reactions and covers important reactions in groundwater relevant to fate of groundwater contaminants. It describes the difficulties in measuring redox conditions and reviews existing methods illustrated with applications.

Cozzarelli, I. M., J. R. McKelvie, and A. L. Baehr. 2014. Volatile hydrocarbons and fuel oxygenates. In Treatise on geochemistry . 2d ed. Vol. 11. Edited by H. D. Holland and K. K. Turekian, 439–480. Oxford: Elsevier.

Provides an overview of sources and processes affecting volatile hydrocarbons and fuel oxygenates in the environment. Reviews the petroleum industry with examples of contamination sources during production, transport, refining, and storage. Covers human exposure pathways and problems with assessing toxicity of mixtures. Describes abiotic and biotic transformations and natural attenuation in groundwater with examples from two case studies.

Fowler, D., M. Coyle, U. Skiba, et al. 2013. The global nitrogen cycle in the twenty-first century. Philosophical Transactions of the Royal Society B-Biological Sciences 368.1621: 13.

DOI: 10.1098/rstb.2013.0164

This review quantifies the sources of reactive nitrogen in the environment. Anthropogenic sources including fertilizer and crops contribute over half of the global sources. The review also covers the amount of unintended N loss to leaching and runoff in agricultural settings globally.

Hashim, M. A., S. Mukhopadhyay, J. N. Sahu, and B. Sengupta. 2011. Remediation technologies for heavy metal contaminated groundwater. Journal of Environmental Management 92.10: 2355–2388.

DOI: 10.1016/j.jenvman.2011.06.009

This highly cited review of remedial technologies for heavy metal contaminated groundwater has tables of speciation and chemistry with references for further reading. A total of thirty-five technologies are described organized into chemical, biological, and physico-chemical processes.

Kuppusamy, S., P. Thavamani, K. Venkateswarlu, Y. B. Lee, R. Naidu, and M. Megharaj. 2017. Remediation approaches for polycyclic aromatic hydrocarbons (PAHs) contaminated soils: Technological constraints, emerging trends and future directions. Chemosphere 168: 944–968.

DOI: 10.1016/j.chemosphere.2016.10.115

This review begins with a ranking of the important sources of PAH contamination, followed by a section on mechanisms for PAH losses. Four established techniques and four emerging technologies for active remediation of PAH-contaminated soil are described and reviewed. The emphasis is on methods that have been proven to work at field sites.

NRC. 2000. Natural attenuation for groundwater remediation . Washington, DC: National Academy Press.

This book reviews the natural attenuation reactions for different classes of contaminants and provides a summary of the likelihood that remediation by natural attenuation will be successful. An excellent chapter on community concerns forms a framework for the issues addressed in the book. A chapter on demonstrating natural attenuation covers methods for mass balance calculations, demonstrating the occurrence of reactions, and principles for assessing uncertainty.

NRC. 2013. Alternatives for managing the nation’s complex contaminated groundwater sites . Washington, DC: National Academy Press.

Discusses how to handle sites with complex geology and sources. It includes eighty case studies and how they were handled.

Ravenscroft, P., H. Brammer, and K. Richards. 2009. Arsenic pollution: A global synthesis . Wiley-Blackwell.

DOI: 10.1002/9781444308785

Provides a worldwide summary of arsenic pollution organized by continent. Chapters cover geochemistry, hydrogeology, agriculture, health effects, methods for removal from drinking water and water supply mitigation.

Rosell, M., S. Lacorte, and D. Barcelo. 2006. Analysis, occurrence and fate of MTBE in the aquatic environment over the past decade. Trac-Trends in Analytical Chemistry 25.10: 1016–1029.

DOI: 10.1016/j.trac.2006.06.011

Provides an overview of the global use of MTBE in gasoline, analytical methods, and occurrence and behavior in the environment. MTBE is one of several oxygenates used in reformulated gasoline. A table comparing chemical and physical properties of fuel oxygenates shows how the properties of MTBE led to its high mobility and difficulty of removal from groundwater by either aeration or biodegradation.

Wiedemeier, T. H., H. S. Rifai, C. J. Newell, and J. T. Wilson. 2007. Natural attenuation of fuels and chlorinated solvents in the subsurface . Hoboken, NJ: John Wiley.

This is a comprehensive book on natural attenuation initially published in 1999 and published online in 2007. Covers principles of natural attenuation, abiotic reactions and intrinsic bioremediation of chlorinated solvents, intrinsic bioremediation of fuels, modeling natural attenuation, and design of long-term monitoring programs. Chapters on case studies of chlorinated solvents and fuels each cover four sites.

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Ground Water Vulnerability Assessment: Predicting Relative Contamination Potential Under Conditions of Uncertainty (1993)

Chapter: 5 case studies, 5 case studies, introduction.

This chapter presents six case studies of uses of different methods to assess ground water vulnerability to contamination. These case examples demonstrate the wide range of applications for which ground water vulnerability assessments are being conducted in the United States. While each application presented here is directed toward the broad goal of protecting ground water, each is unique in its particular management requirements. The intended use of the assessment, the types of data available, the scale of the assessments, the required resolution, the physical setting, and institutional factors all led to very different vulnerability assessment approaches. In only one of the cases presented here, Hawaii, are attempts made to quantify the uncertainty associated with the assessment results.

Introduction

Ground water contamination became an important political and environmental issue in Iowa in the mid-1980s. Research reports, news headlines, and public debates noted the increasing incidence of contaminants in rural and urban well waters. The Iowa Ground water Protection Strategy (Hoyer et al. 1987) indicated that levels of nitrate in both private and municipal

wells were increasing. More than 25 percent of the state's population was served by water with concentrations of nitrate above 22 milligrams per liter (as NO 3 ). Similar increases were noted in detections of pesticides in public water supplies; about 27 percent of the population was periodically consuming low concentrations of pesticides in their drinking water. The situation in private wells which tend to be shallower than public wells may have been even worse.

Defining the Question

Most prominent among the sources of ground water contamination were fertilizers and pesticides used in agriculture. Other sources included urban use of lawn chemicals, industrial discharges, and landfills. The pathways of ground water contamination were disputed. Some interests argued that contamination occurs only when a natural or human generated condition, such as sinkholes or agricultural drainage wells, provides preferential flow to underground aquifers, resulting in local contamination. Others suggested that chemicals applied routinely to large areas infiltrate through the vadose zone, leading to widespread aquifer contamination.

Mandate, Selection, and Implementation

In response to growing public concern, the state legislature passed the Iowa Ground water Protection Act in 1987. This landmark statute established the policy that further contamination should be prevented to the "maximum extent practical" and directed state agencies to launch multiyear programs of research and education to characterize the problem and identify potential solutions.

The act mandated that the Iowa Department of Natural Resources (DNR) assess the vulnerability of the state's ground water resources to contamination. In 1991, DNR released Ground water Vulnerability Regions of Iowa , a map developed specifically to depict the intrinsic susceptibility of ground water resources to contamination by surface or near-surface activities. This assessment had three very limited purposes: (1) to describe the physical setting of ground water resources in the state, (2) to educate policy makers and the public about the potential for ground water contamination, and (3) to provide guidance for planning and assigning priorities to ground water protection efforts in the state.

Unlike other vulnerability assessments, the one in Iowa took account of factors that affect both ground water recharge and well development. Ground water recharge involves issues related to aquifer contamination; well development involves issues related to contamination of water supplies in areas where sources other than bedrock aquifers are used for drinking water. This

approach considers jointly the potential impacts of contamination on the water resource in aquifers and on the users of ground water sources.

The basic principle of the Iowa vulnerability assessment involves the travel time of water from the land surface to a well or an aquifer. When the time is relatively short (days to decades), vulnerability is considered high. If recharge occurs over relatively long periods (centuries to millennia), vulnerability is low. Travel times were determined by evaluating existing contaminants and using various radiometric dating techniques. The large reliance on travel time in the Iowa assessment likely results in underestimation of the potential for eventual contamination of the aquifer over time.

The most important factor used in the assessment was thickness of overlying materials which provide natural protection to a well or an aquifer. Other factors considered included type of aquifer, natural water quality in an aquifer, patterns of well location and construction, and documented occurrences of well contamination. The resulting vulnerability map ( Plate 1 ) delineates regions having similar combinations of physical characteristics that affect ground water recharge and well development. Qualitative ratings are assigned to the contamination potential for aquifers and wells for various types and locations of water sources. For example, the contamination potential for wells in alluvial aquifers is considered high, while the potential for contamination of a variable bedrock aquifer protected by moderate drift or shale is considered low.

Although more sophisticated approaches were investigated for use in the assessment, ultimately no complex process models of contaminant transport were used and no distinction was made among Iowa's different soil types. The DNR staff suggested that since the soil cover in most of the state is such a small part of the overall aquifer or well cover, processes that take place in those first few inches are relatively similar and, therefore, insignificant in terms of relative susceptibilities to ground water contamination. The results of the vulnerability assessment followed directly from the method's assumptions and underlying principles. In general, the thicker the overlay of clayey glacial drift or shale, the less susceptible are wells or aquifers to contamination. Where overlying materials are thin or sandy, aquifer and well susceptibilities increase. Vulnerability is also greater in areas where sinkholes or agricultural drainage wells allow surface and tile water to bypass natural protective layers of soil and rapidly recharge bedrock aquifers.

Basic data on geologic patterns in the state were extrapolated to determine the potential for contamination. These data were supplemented by databases on water contamination (including the Statewide Rural Well-Water Survey conducted in 1989-1990) and by research insights into the transport, distribution, and fate of contaminants in ground water. Some of the simplest data needed for the assessment were unavailable. Depth-to-bedrock information had never been developed, so surface and bedrock topographic

maps were revised and integrated to create a new statewide depth-to-bedrock map. In addition, information from throughout the state was compiled to produce the first statewide alluvial aquifer map. All new maps were checked against available well-log data, topographic maps, outcrop records, and soil survey reports to assure the greatest confidence in this information.

While the DNR was working on the assessment, it was also asked to integrate various types of natural resource data into a new computerized geographic information system (GIS). This coincident activity became a significant contributor to the assessment project. The GIS permitted easier construction of the vulnerability map and clearer display of spatial information. Further, counties or regions in the state can use the DNR geographic data and the GIS to explore additional vulnerability parameters and examine particular areas more closely to the extent that the resolution of the data permits.

The Iowa vulnerability map was designed to provide general guidance in planning and ranking activities for preventing contamination of aquifers and wells. It is not intended to answer site-specific questions, cannot predict contaminant concentrations, and does not even rank the different areas of the state by risk of contamination. Each of these additional uses would require specific assessments of vulnerability to different activities, contaminants, and risk. The map is simply a way to communicate qualitative susceptibility to contamination from the surface, based on the depth and type of cover, natural quality of the aquifer, well location and construction, and presence of special features that may alter the transport of contaminants.

Iowa's vulnerability map is viewed as an intermediate product in an ongoing process of learning more about the natural ground water system and the effects of surface and near-surface activities on that system. New maps will contain some of the basic data generated by the vulnerability study. New research and data collection will aim to identify ground water sources not included in the analysis (e.g., buried channel aquifers and the "salt and pepper sands" of western Iowa). Further analyses of existing and new well water quality data will be used to clarify relationships between aquifer depth and ground water contamination. As new information is obtained, databases and the GIS will be updated. Over time, new vulnerability maps may be produced to reflect new data or improved knowledge of environmental processes.

The Cape Cod sand and gravel aquifer is the U.S. Environmental Protection Agency (EPA) designated sole source of drinking water for Barnstable County, Massachusetts (ca. 400 square miles, winter population 186,605 in 1990, summer population ca. 500,000) as well as the source of fresh water for numerous kettle hole ponds and marine embayments. During the past 20 years, a period of intense development of open land accompanied by well-reported ground water contamination incidents, Cape Cod has been the site of intensive efforts in ground water management and analysis by many organizations, including the Association for the Preservation of Cape Cod, the U.S. Geological Survey, the Massachusetts Department of Environmental Protection (formerly the Department of Environmental Quality Engineering), EPA, and the Cape Cod Commission (formerly the Cape Cod Planning and Economic Development Commission). An earlier NRC publication, Ground Water Quality Protection: State and Local Strategies (1986) summarizes the Cape Cod ground water protection program.

The Area Wide Water Quality Management Plan for Cape Cod (CCPEDC 1978a, b), prepared in response to section 208 of the federal Clean Water Act, established a management strategy for the Cape Cod aquifer. The plan emphasized wellhead protection of public water supplies, limited use of public sewage collection systems and treatment facilities, and continued general reliance on on-site septic systems, and relied on density controls for regulation of nitrate concentrations in public drinking water supplies. The water quality management planning program began an effort to delineate the zones of contribution (often called contributing areas) for public wells on Cape Cod that has become increasingly sophisticated over the years. The effort has grown to address a range of ground water resources and ground water dependent resources beyond the wellhead protection area, including fresh and marine surface waters, impaired areas, and water quality improvement areas (CCC 1991). Plate 2 depicts the water resources classifications for Cape Cod.

Selection and Implementation of Approaches

The first effort to delineate the contributing area to a public water supply well on Cape Cod came in 1976 as part of the initial background studies for the Draft Area Wide Water Quality Management Plan for Cape

Cod (CCPEDC 1978a). This effort used a simple mass balance ratio of a well's pumping volume to an equal volume average annual recharge evenly spread over a circular area. This approach, which neglects any hydrogeologic characteristics of the aquifer, results in a number of circles of varying radii that are centered at the wells.

The most significant milestone in advancing aquifer protection was the completion of a regional, 10 foot contour interval, water table map of the county by the USGS (LeBlanc and Guswa 1977). By the time that the Draft and Final Area Wide Water Quality Management Plans were published (CCPEDC 1978a, b), an updated method for delineating zones of contribution, using the regional water table map, had been developed. This method used the same mass balance approach to characterize a circle, but also extended the zone area by 150 percent of the circle's radius in the upgradient direction. In addition, a water quality watch area extending upgradient from the zone to the ground water divide was recommended. Although this approach used the regional water table map for information on ground water flow direction, it still neglected the aquifer's hydrogeologic parameters.

In 1981, the USGS published a digital model of the aquifer that included regional estimates of transmissivity (Guswa and LeBlanc 1981). In 1982, the CCPEDC used a simple analytical hydraulic model to describe downgradient and lateral capture limits of a well in a uniform flow field (Horsley 1983). The input parameters required for this model included hydraulic gradient data from the regional water table map and transmissivity data from the USGS digital model. The downgradient and lateral control points were determined using this method, but the area of the zone was again determined by the mass balance method. Use of the combined hydraulic and mass balance method resulted in elliptical zones of contribution that did not extend upgradient to the ground water divide. This combined approach attempted to address three-dimensional ground water flow beneath a partially penetrating pumping well in a simple manner.

At about the same time, the Massachusetts Department of Environmental Protection started the Aquifer Lands Acquisition (ALA) Program to protect land within zones of contribution that would be delineated by detailed site-specific studies. Because simple models could not address three-dimensional flow and for several other reasons, the ALA program adopted a policy that wellhead protection areas or Zone IIs (DEP-WS 1991) should be extended upgradient all the way to a ground water divide. Under this program, wells would be pump tested for site-specific aquifer parameters and more detailed water table mapping would often be required. In many cases, the capture area has been delineated by the same simple hydraulic analytical model but the zone has been extended to the divide. This method has resulted in some 1989 zones that are 3,000 feet wide and extend 4.5

miles upgradient, still without a satisfactory representation of three-dimensional flow to the well.

Most recently the USGS (Barlow 1993) has completed a detailed subregional, particle-tracking three-dimensional ground water flow model that shows the complex nature of ground water flow to wells. This approach has shown that earlier methods, in general, overestimate the area of zones of contribution (see Figure 5.1 ).

In 1988, the public agencies named above completed the Cape Cod Aquifer Management Project (CCAMP), a resource-based ground water protection study that used two towns, Barnstable and Eastham, to represent the more and less urbanized parts of Cape Cod. Among the CCAMP products were a GIS-based assessment of potential for contamination as a result of permissible land use changes in the Barnstable zones of contribution (Olimpio et al. 1991) and a ground water vulnerability assessment by Heath (1988) using DRASTIC for the same area. Olimpio et al. characterized land uses by ranking potential contaminant sources without regard to differences in vulnerability within the zones. Heath's DRASTIC analysis of the same area, shown in Figure 5.2 , delineated two distinct zones of vulnerability based on hydrogeologic setting. The Sandwich Moraine setting, with deposits of silt, sand and gravel, and depths to ground water ranging from 0 to more than 125 feet, had DRASTIC values of 140 to 185; the Barnstable Outwash Plain, with permeable sand and fine gravel deposits with beds of silt and clay and depths to ground water of less than 50 feet, yielded values of 185 to 210. The DRASTIC scores and relative contributions of the factors are shown in Tables 5.1 and 5.2 . Heath concluded that similar areas of Cape Cod would produce similar moderate to high vulnerability DRASTIC scores. The CCAMP project also addressed the potential for contamination of public water supply wells from new land uses allowable under existing zoning for the same area. The results of that effort are shown in Plate 4 .

In summary, circle zones were used initially when the hydrogeologic nature of the aquifer or of hydraulic flow to wells was little understood. The zones improved with an understanding of ground water flow and aquifer characteristics, but in recognition of the limitations of regional data, grossly conservative assumptions came into use. Currently, a truer delineation of a zone of contribution can be prepared for a given scenario using sophisticated models and highly detailed aquifer characterization. However, the area of a given zone still is highly dependent on the initial assumptions that dictate how much and in what circumstances a well is pumped. In the absence of ability to specify such conditions, conservative assumptions,

FIGURE 5.1 Contributing areas of wells and ponds in the complex flow system determined by using the three-dimensional model with 1987 average daily pumping rates. (Barlow 1993)

such as maximum prolonged pumping, prevail, and, therefore, conservatively large zones of contribution continue to be used for wellhead protection.

The ground water management experience of Cape Cod has resulted in a better understanding of the resource and the complexity of the aquifer

FIGURE 5.2 DRASTIC contours for Zone 1, Barnstable-Yarmouth, Massachusetts.

system, as well as the development of a more ambitious agenda for resource protection. Beginning with goals of protection of existing public water supplies, management interests have grown to include the protection of private wells, potential public supplies, fresh water ponds, and marine embayments. Public concerns over ground water quality have remained high and were a major factor in the creation of the Cape Cod Commission by the Massachusetts legislature. The commission is a land use planning and regulatory agency with broad authority over development projects and the ability to create special resource management areas. The net result of 20 years of effort by many individuals and agencies is the application of

TABLE 5.1 Ranges, Rating, and Weights for DRASTIC Study of Barnstable Outwash Plain Setting (NOTE: gpd/ft 2 = gallons per day per square foot) (Heath 1988)

TABLE 5.2 Ranges, Rating, and Weights for DRASTIC Study of Sandwich Moraine Setting (NOTE: gpd/ft 2 = gallons per day per square foot) (Heath 1988)

higher protection standards to broader areas of the Cape Cod aquifer. With some exceptions for already impaired areas, a differentiated resource protection approach in the vulnerable aquifer setting of Cape Cod has resulted in a program that approaches universal ground water protection.

Florida has 13 million residents and is the fourth most populous state (U.S. Bureau of the Census 1991). Like several other sunbelt states, Florida's population is growing steadily, at about 1,000 persons per day, and is estimated to reach 17 million by the year 2000. Tourism is the biggest industry in Florida, attracting nearly 40 million visitors each year. Ground water is the source of drinking water for about 95 percent of Florida's population; total withdrawals amount to about 1.5 billion gallons per day. An additional 3 billion gallons of ground water per day are pumped to meet the needs of agriculture—a $5 billion per year industry, second only to tourism in the state. Of the 50 states, Florida ranks eighth in withdrawal of fresh ground water for all purposes, second for public supply, first for rural domestic and livestock use, third for industrial/commercial use, and ninth for irrigation withdrawals.

Most areas in Florida have abundant ground water of good quality, but the major aquifers are vulnerable to contamination from a variety of land use activities. Overpumping of ground water to meet the growing demands of the urban centers, which accounts for about 80 percent of the state's population, contributes to salt water intrusion in coastal areas. This overpumping is considered the most significant problem for degradation of ground water quality in the state. Other major sources of ground water contaminants include: (1) pesticides and fertilizers (about 2 million tons/year) used in agriculture, (2) about 2 million on-site septic tanks, (3) more than 20,000 recharge wells used for disposing of stormwater, treated domestic wastewater, and cooling water, (4) nearly 6,000 surface impoundments, averaging one per 30 square kilometers, and (5) phosphate mining activities that are estimated to disturb about 3,000 hectares each year.

The Hydrogeologic Setting

The entire state is in the Coastal Plain physiographic province, which has generally low relief. Much of the state is underlain by the Floridan aquifer system, largely a limestone and dolomite aquifer that is found in both confined and unconfined conditions. The Floridan is overlain through most of the state by an intermediate aquifer system, consisting of predominantly clays and sands, and a surficial aquifer system, consisting of predominantly sands, limestone, and dolomite. The Floridan is one of the most productive aquifers in the world and is the most important source of drinking water for Florida residents. The Biscayne, an unconfined, shallow, limestone aquifer located in southeast Florida, is the most intensively used

aquifer and the sole source of drinking water for nearly 3 million residents in the Miami-Palm Beach coastal area. Other surficial aquifers in southern Florida and in the western panhandle region also serve as sources of ground water.

Aquifers in Florida are overlain by layers of sand, clay, marl, and limestone whose thickness may vary considerably. For example, the thickness of layers above the Floridan aquifer range from a few meters in parts of west-central and northern Florida to several hundred meters in south-central Florida and in the extreme western panhandle of the state. Four major groups of soils (designated as soil orders under the U.S. Soil Taxonomy) occur extensively in Florida. Soils in the western highlands are dominated by well-drained sandy and loamy soils and by sandy soils with loamy subsoils; these are classified as Ultisols and Entisols. In the central ridge of the Florida peninsula, are found deep, well-drained, sandy soils (Entisols) as well as sandy soils underlain by loamy subsoils or phosphatic limestone (Alfisols and Ultisols). Poorly drained sandy soils with organic-rich and clay-rich subsoils, classified as Spodosols, occur in the Florida flatwoods. Organic-rich muck soils (Histosols) underlain by muck or limestone are found primarily in an area extending south of Lake Okeechobee.

Rainfall is the primary source of ground water in Florida. Annual rainfall in the state ranges from 100 to 160 cm/year, averaging 125 cm/year, with considerable spatial (both local and regional) and seasonal variations in rainfall amounts and patterns. Evapotranspiration (ET) represents the largest loss of water; ET ranges from about 70 to 130 cm/year, accounting for between 50 and 100 percent of the average annual rainfall. Surface runoff and ground water discharge to streams averages about 30 cm/year. Annual recharge to surficial aquifers ranges from near zero in perennially wet, lowland areas to as much as 50 cm/year in well-drained areas; however, only a fraction of this water recharges the underlying Floridan aquifer. Estimates of recharge to the Floridan aquifer vary from less than 3 cm/year to more than 25 cm/year, depending on such factors as weather patterns (e.g., rainfall-ET balance), depth to water table, soil permeability, land use, and local hydrogeology.

Permeable soils, high net recharge rates, intensively managed irrigated agriculture, and growing demands from urban population centers all pose considerable threat of ground water contamination. Thus, protection of this valuable natural resource while not placing unreasonable constraints on agricultural production and urban development is the central focus of environmental regulation and growth management in Florida.

Along with California, Florida has played a leading role in the United

States in development and enforcement of state regulations for environmental protection. Detection in 1983 of aldicarb and ethylene dibromide, two nematocides used widely in Florida's citrus groves, crystallized the growing concerns over ground water contamination and the need to protect this vital natural resource. In 1983, the Florida legislature passed the Water Quality Assurance Act, and in 1984 adopted the State and Regional Planning Act. These and subsequent legislative actions provide the legal basis and guidance for the Ground Water Strategy developed by the Florida Department of Environmental Regulation (DER).

Ground water protection programs in Florida are implemented at federal, state, regional, and local levels and involve both regulatory and nonregulatory approaches. The most significant nonregulatory effort involves more than 30 ground water studies being conducted in collaboration with the Water Resources Division of the U.S. Geological Survey. At the state level, Florida statutes and administrative codes form the basis for regulatory actions. Although DER is the primary agency responsible for rules and statutes designed to protect ground water, the following state agencies participate to varying degrees in their implementation: five water management districts, the Florida Geological Survey, the Department of Health and Rehabilitative Services (HRS), the Department of Natural Resources, and the Florida Department of Agriculture and Consumer Services (DACS). In addition, certain interagency committees help coordinate the development and implementation of environmental codes in the state. A prominent example is the Pesticide Review Council which offers guidance to the DACS in developing pesticide use regulation. A method for screening pesticides in terms of their chronic toxicity and environmental behavior has been developed through collaborative efforts of the DACS, the DER, and the HRS (Britt et al. 1992). This method will be used to grant registration for pesticide use in Florida or to seek additional site-specific field data.

Selecting an Approach

The emphasis of the DER ground water program has shifted in recent years from primarily enforcement activity to a technically based, quantifiable, planned approach for resource protection.

The administrative philosophy for ground water protection programs in Florida is guided by the following principles:

Ground water is a renewable resource, necessitating a balance between withdrawals and natural or artificial recharge.

Ground water contamination should be prevented to the maximum degree possible because cleanup of contaminated aquifers is technically or economically infeasible.

It is impractical, perhaps unnecessary, to require nondegradation standards for all ground water in all locations and at all times.

The principle of ''most beneficial use" is to be used in classifying ground water into four classes on the basis of present quality, with the goal of attaining the highest level protection of potable water supplies (Class I aquifers).

Part of the 1983 Water Quality Assurance Act requires Florida DER to "establish a ground water quality monitoring network designed to detect and predict contamination of the State's ground water resources" via collaborative efforts with other state and federal agencies. The three basic goals of the ground water quality monitoring program are to:

Establish the baseline water quality of major aquifer systems in the state,

Detect and predict changes in ground water quality resulting from the effects of various land use activities and potential sources of contamination, and

Disseminate to local governments and the public, water quality data generated by the network.

The ground water monitoring network established by DER to meet the goals stated above consists of two major subnetworks and one survey (Maddox and Spicola 1991). Approximately 1,700 wells that tap all major potable aquifers in the state form the Background Network, which was designed to help define the background water quality. The Very Intensively Studied Area (VISA) network was established to monitor specific areas of the state considered highly vulnerable to contamination; predominant land use and hydrogeology were the primary attributes used to evaluate vulnerability. The DRASTIC index, developed by EPA, served as the basis for statewide maps depicting ground water vulnerability. Data from the VISA wells will be compared to like parameters sampled from Background Network wells in the same aquifer segment. The final element of the monitoring network is the Private Well Survey, in which up to 70 private wells per county will be sampled. The sampling frequency and chemical parameters to be monitored at each site are based on several factors, including network well classification, land use activities, hydrogeologic sensitivity, and funding. In Figure 5.3 , the principal aquifers in Florida are shown along with the distribution of the locations of the monitoring wells in the Florida DER network.

The Preservation 2000 Act, enacted in 1990, mandated that the Land Acquisition Advisory Council (LAAC) "provide for assessing the importance

FIGURE 5.3 Principal aquifers in Florida and the network of sample wells as of March 1990 (1642 wells sampled). (Adapted from Maddox and Spicola 1991, and Maddox et al. 1993.)

of acquiring lands which can serve to protect or recharge ground water, and the degree to which state land acquisition programs should focus on purchasing such land." The Ground Water Resources Committee, a subcommittee of the LAAC, produced a map depicting areas of ground water significance at regional scale (1:500,000) (see Figure 5.4 ) to give decision makers the basis for considering ground water as a factor in land acquisition under the Preservation 2000 Act (LAAC 1991). In developing maps for their districts, each of the five water management districts (WMDs) used the following criteria: ground water recharge, ground water quality, aquifer vulnerability, ground water availability, influence of existing uses on the resource, and ground water supply. The specific approaches used by

FIGURE 5.4 General areas of ground water significance in Florida. (Map provided by Florida Department of Environmental Regulation, Bureau of Drinking Water and Ground Water Resources.)

the WMDs varied, however. For example, the St. Johns River WMD used a GIS-based map overlay and DRASTIC-like numerical index approach that rated the following attributes: recharge, transmissivity, water quality, thickness of potable water, potential water expansion areas, and spring flow capture zones. The Southwest Florida WMD also used a map overlay and index approach which considered four criteria, and GIS tools for mapping. Existing databases were considered inadequate to generate a DRASTIC map for the Suwannee River WMD, but the map produced using an overlay approach was considered to be similar to DRASTIC maps in providing a general depiction of aquifer vulnerability.

In the November 1988, Florida voters approved an amendment to the Florida Constitution allowing land producing high recharge to Florida's aquifers to be classified and assessed for ad valorem tax purposes based on character or use. Such recharge areas are expected to be located primarily in the upland, sandy ridge areas. The Bluebelt Commission appointed by the 1989 Florida Legislature, studied the complex issues involved and recommended that the tax incentive be offered to owners of such high recharge areas if their land is left undeveloped (SFWMD 1991). The land eligible

for classification as "high water recharge land" must meet the following criteria established by the commission:

The parcel must be located in the high recharge areas designated on maps supplied by each of the five WMDs.

The high recharge area of the parcel must be at least 10 acres.

The land use must be vacant or single-family residential.

The parcel must not be receiving any other special assessment, such as Greenbelt classification for agricultural lands.

Two bills related to the implementation of the Bluebelt program are being considered by the 1993 Florida legislation.

THE SAN JOAQUIN VALLEY

Pesticide contamination of ground water resources is a serious concern in California's San Joaquin Valley (SJV). Contamination of the area's aquifer system has resulted from a combination of natural geologic conditions and human intervention in exploiting the SJV's natural resources. The SJV is now the principal target of extensive ground water monitoring activities in the state.

Agriculture has imposed major environmental stresses on the SJV. Natural wetlands have been drained and the land reclaimed for agricultural purposes. Canal systems convey water from the northern, wetter parts of the state to the south, where it is used for irrigation and reclamation projects. Tens of thousands of wells tap the sole source aquifer system to supply water for domestic consumption and crop irrigation. Cities and towns have sprouted throughout the region and supply the human resources necessary to support the agriculture and petroleum industries.

Agriculture is the principal industry in California. With 1989 cash receipts of more than $17.6 billion, the state's agricultural industry produced more than 50 percent of the nation's fruits, nuts, and vegetables on 3 percent of the nation's farmland. California agriculture is a diversified industry that produces more than 250 crop and livestock commodities, most of which can be found in the SJV.

Fresno County, the largest agricultural county in the state, is situated in the heart of the SJV, between the San Joaquin River to the north and the Kings River on the south. Grapes, stone fruits, and citrus are important commodities in the region. These and many other commodities important to the region are susceptible to nematodes which thrive in the county's coarse-textured soils.

While agricultural diversity is a sound economic practice, it stimulates the growth of a broad range of pest complexes, which in turn dictates greater reliance on agricultural chemicals to minimize crop losses to pests, and maintain productivity and profit. Domestic and foreign markets demand high-quality and cosmetically appealing produce, which require pesticide use strategies that rely on pest exclusion and eradication rather than pest management.

Hydrogeologic Setting

The San Joaquin Valley (SJV) is at the southern end of California's Central Valley. With its northern boundary just south of Sacramento, the Valley extends in a southeasterly direction about 400 kilometers (250 miles) into Kern County. The SJV averages 100 kilometers (60 miles) in width and drains the area between the Sierra Nevada on the east and the California Coastal Range on the west. The rain shadow caused by the Coastal Range results in the predominantly xeric habitat covering the greater part of the valley floor where the annual rainfall is about 25 centimeters (10 inches). The San Joaquin River is the principal waterway that drains the SJV northward into the Sacramento Delta region.

The soils of the SJV vary significantly. On the west side of the valley, soils are composed largely of sedimentary materials derived from the Coastal Range; they are generally fine-textured and slow to drain. The arable soils of the east side developed on relatively unweathered, granitic sediments. Many of these soils are wind-deposited sands underlain by deep coarse-textured alluvial materials.

From the mid-1950s until 1977, dibromochloropropane (DBCP) was the primary chemical used to control nematodes. DBCP has desirable characteristics for a nematocide. It is less volatile than many other soil fumigants, such as methylbromide; remains active in the soil for a long time, and is effective in killing nematodes. However, it also causes sterility in human males, is relatively mobile in soil, and is persistent. Because of the health risks associated with consumption of DBCP treated foods, the nematocide was banned from use in the United States in 1979. After the ban, several well water studies were conducted in the SJV by state, county and local authorities. Thirteen years after DBCP was banned, contamination of well waters by the chemical persists as a problem in Fresno County.

Public concern over pesticides in ground water resulted in passage of the California Pesticide Contamination Prevention Act (PCPA) of 1985. It is a broad law that establishes the California Department of Pesticide Regulation

as the lead agency in dealing with issues of ground water contamination by pesticides. The PCPA specifically requires:

pesticide registrants to collect and submit specific chemical and environmental fate data (e.g., water solubility, vapor pressure, octanol-water partition coefficient, soil sorption coefficient, degradation half-lives for aerobic and anaerobic metabolism, Henry's Law constant, hydrolysis rate constant) as part of the terms for registration and continued use of their products in California.

establishment of numerical criteria or standards for physical-chemical characteristics and environmental fate data to determine whether a pesticide can be registered in the state that are at least as stringent as those standards set by the EPA,

soil and water monitoring investigations be conducted on:

pesticides with properties that are in violation of the physical-chemical standards set in 2 above, and

pesticides, toxic degradation products or other ingredients that are:

contaminants of the state's ground waters, or

found at the deepest of the following soil depths:

2.7 meters (8 feet) below the soil surface,

below the crop root zone, or

below the microbial zone, and

creation of a database of wells sampled for pesticides with a provision requiring all agencies to submit data to the California Department of Pesticide Regulation (CDPR).

Difficulties associated with identifying the maximum depths of root zone and microbial zone have led to the establishment of 8 feet as a somewhat arbitrary but enforceable criterion for pesticide leaching in soils.

Selection and Implementation of an Approach

Assessment of ground water vulnerability to pesticides in California is a mechanical rather than a scientific process. Its primary goal is compliance with the mandates established in the PCPA. One of these mandates requires that monitoring studies be conducted in areas of the state where the contaminant pesticide is used, in other areas exhibiting high risk portraits (e.g., low organic carbon, slow soil hydrolysis, metabolism, or dissipation), and in areas where pesticide use practices present a risk to the state's ground water resources.

The numerical value for assessments was predetermined by the Pesticide Use Report (PUR) system employed in the state. Since the early

1970s, California has required pesticide applicators to give local authorities information on the use of restricted pesticides. This requirement was extended to all pesticides beginning in 1990. Application information reported includes names of the pesticide(s) and commodities, the amount applied, the formulation used, and the location of the commodity to the nearest section (approximately 1 square mile) as defined by the U.S. Rectangular Coordinate System. In contrast to most other states that rely on county pesticide sales in estimating pesticide use, California can track pesticide use based on quantities applied to each section. Thus, the section, already established as a political management unit, became the basic assessment unit.

The primary criteria that subject a pesticide to investigation as a ground water pollutant are:

detection of the pesticide or its metabolites in well samples, or

its failure to conform to the physical-chemical standards set in accordance with the PCPA, hence securing its position on the PCPA's Ground Water Protection List of pesticides having a potential to pollute ground water.

In either case, relatively large areas surrounding the original detection site or, in the latter case, high use regions are monitored via well surveys. Positive findings automatically increase the scope of the surveys, and since no tolerance levels are specified in the PCPA, any detectable and confirmed result establishes a pesticide as a contaminant.

When a pesticide or its degradation products is detected in a well water sample and the pesticide is judged to have contaminated the water source as a result of a legal agricultural use, the section the well is in is declared a Pesticide Management Zone (PMZ). Further application of the detected pesticide within PMZ boundaries may be prohibited or restricted, depending on the degree of contamination and subject to the availability of tried and tested modifications in management practices addressing environmental safety in use of the pesticide. PMZs are pesticide-specific—each contaminant pesticide has its own set of PMZs which may or may not overlap PMZs assigned another pesticide. Currently, consideration is being given to the extension of PMZs established for one chemical to other potential pesticide pollutants. In addition to monitoring activities in PMZs, protocols have been written to monitor ground water in sections adjacent to a PMZ. Monitoring of adjacent sections has resulted in many new PMZs. Currently, California has 182 PMZs involving five registered pesticides.

California has pursued this mechanical approach to assessing ground water vulnerability to pesticides for reasons that cover a spectrum of political, economic, and practical concerns. As noted earlier, the scale of the assessment unit was set at the section level because it is a well-defined

geopolitical unit used in the PUR system. Section boundaries frequently are marked by roads and highways, which allows the section to be located readily and makes enforcement of laws and regulations more practical. California law also requires that well logs be recorded by drillers for all wells in the state. Well-site information conforms to the U.S. Rectangular Coordinate System's township, range, and section system.

The suitability and reliability of databases available for producing vulnerability assessments was a great concern before passage of the PCPA in 1985. Soil survey information holds distinct advantages for producing assessments and developing best management practices strategies, but it was not available in a format that could work in harmony with PUR sections. To date, several areas of the SJV are not covered by a modern soil survey; they include the western part of Tulare County, which contains 34 PMZs. Other vadose zone data were sparse, it available at all.

The use of models was not considered appropriate, given the available data and because no single model could cope with the circumstances in which contaminated ground water sources were being discovered in the state. While most cases of well contamination were associated with the coarse-textured soils of the SJV and the Los Angeles Basin, several cases were noted in areas of the Central Valley north of the SJV, where very dense fine-textured soils (vertisols and other cracking clays) were dominant.

The potential vagaries and uncertainties associated with more scientific approaches to vulnerability assessment, given the tools available when the PCPA was enacted, presented too large a risk for managers to consider endorsing their use. In contrast, the basic definition of the PMZ is difficult to challenge (pesticide contamination has been detected or not detected) in the legal sense. And the logic of investing economic resources in areas immediately surrounding areas of acknowledged contamination are relatively undisputable. The eastern part of the SJV contains more than 50 percent of the PMZs in the state. Coarse-textured soils of low carbon content are ubiquitous in this area and are represented in more than 3,000 sections. The obvious contamination scenario is the normal scenario in the eastern SJV, and because of its size it creates a huge management problem. While more sophisticated methods for assessing ground water vulnerability have been developed, a question that begs to be asked is "How would conversion to the use of enhanced techniques for evaluating ground water vulnerability improve ground water protection policy and management in the SJV?"

More than 90 percent of the population of Hawaii depends on ground water (nearly 200 billion gallons per day) for their domestic supply (Au 1991). Ground water contamination is of special concern in Hawaii, as in other insular systems, where alternative fresh water resources are not readily available or economically practical. Salt water encroachment, caused by pumping, is by far the biggest source of ground water contamination in Hawaii; however, nonpoint source contamination from agricultural chemicals is increasingly a major concern. On Oahu, where approximately 80 percent of Hawaii's million-plus population resides, renewable ground water resources are almost totally exploited; therefore, management action to prevent contamination is essential.

Each of the major islands in the Hawaiian chain is formed from one or more shield volcanoes composed primarily of extremely permeable thin basaltic lava flows. On most of the Hawaiian islands the margins of the volcanic mountains are overlapped by coastal plain sediments of alluvial and marine origin that were deposited during periods of volcanic quiescence. In general, the occurrence of ground water in Hawaii, shown in Figure 5.5 , falls into three categories: (1) basal water bodies floating on and displacing salt water, (2) high-level water bodies impounded within compartments formed by impermeable dikes that intrude the lava flows, and (3) high-level water bodies perched on ash beds or soils interbedded with

FIGURE 5.5 Cross section of a typical volcanic dome showing the occurrence of ground water in Hawaii (After Peterson 1972. Reprinted, by permission, from Water Well Journal Publishing Company, 1972.)

thin lava flows on unconformities or on other relatively impervious lava flows (Peterson 1972).

A foundation of the tourist industry in Hawaii is the pristine environment. The excellent quality of Hawaii's water is well known. The public has demanded, and regulatory agencies have adopted, a very conservative, zero-tolerance policy on ground water contamination. The reality, however, is that past, present, and future agricultural, industrial, and military activities present potentially significant ground water contamination problems in Hawaii.

Since 1977 when 1,874 liters of ethylene dibromide (EDB) where spilled within 18 meters of a well near Kunia on the island of Oahu, the occurrence and distribution of contaminants in Hawaii's ground water has been carefully documented by Oki and Giambelluca (1985, 1987) and Lau and Mink (1987). Before 1981, when the nematocide dibromochloropropane (DBCP) was found in wells in central Oahu, the detection limit for most chemicals was too high to reveal the low level of contamination that probably had existed for many years.

Concern about the fate of agriculture chemicals led the Hawaii State Department of Agriculture to initiate a large sampling program to characterize the sources of nonpoint ground water contamination. In July 1983, 10 wells in central Oahu were closed because of DBCP and EDB contamination. The public has been kept well informed of possible problems through the publication of maps of chemicals detected in ground water in the local newspaper. Updated versions of these maps are shown in Figures 5.6a , b , c , and d .

In Hawaii, interagency committees, with representation from the Departments of Health and Agriculture, have been formed to address the complex technical and social questions associated with ground water contamination from agricultural chemicals. The Hawaii legislature has provided substantial funding to groups at the University of Hawaii to develop the first GIS-based regional scale chemical leaching assessment approach to aid in pesticide regulation. This effort, described below, has worked to identify geographic areas of concern, but the role the vulnerability maps generated by this system will play in the overall regulatory process is still unclear.

Agrichemicals are essential to agriculture in Hawaii. It is not possible to maintain a large pineapple monoculture in Hawaii without nematode control using pesticides. Pineapple and sugar growers in Hawaii have generally employed well controlled management practices in their use of fertilizers, herbicides, and insecticides. In the early 1950s, it was thought that organic chemicals such as DBCP and EDB would not leach to ground water

FIGURE 5.6a The occurrence and distribution of ground water contamination on the Island of Oahu. (Map provided by Hawaii State Department of Health.)

FIGURE 5.6b The occurrence and distribution of ground water contamination on the Island of Hawaii. (Map provided by Hawaii State Department of Health.)

FIGURE 5.6c The occurrence and distribution of ground water contamination on the Island of Maui. (Map provided by Hawaii State Department of Health.)

FIGURE 5.6d The occurrence and distribution of ground water contamination on the Island of Kauai. (Map provided by Hawaii State Department of Health.)

because (1) the chemicals are highly sorbed in soils with high organic carbon contents, (2) the chemicals are highly volatile, and (3) the water table is several hundred meters below the surface. Measured concentrations of DBCP and EDB down to 30 meters at several locations have shown the original assessment to be wrong. They have resulted in an urgent need to understand processes such as preferential flow better and to predict if the replacement chemicals used today, such as Telon II, will also leach to significant depths.

Leaching of pesticides to ground water in Hawaii could take decades. This time lag could lead to a temporary false sense of security, as happened in the past and potentially result in staggering costs for remedial action. For this reason, mathematical models that permit the user to ask ''what if" questions have been developed to help understand what the future may hold under certain management options. One needs to know what the fate of chemicals applied in the past will be and how to regulate the chemicals considered for use in the future; models are now being developed and used to help make these vulnerability assessments.

Researchers have embarked on several parallel approaches to quantitatively assess the vulnerability of Hawaii's ground water resources, including: (1) sampling, (2) physically-based numerical modeling, and (3) vulnerability mapping based on a simple chemical leaching index. Taken together these approaches have provided insight and guidance for work on a complex, spatially and temporally variable problem.

The sampling programs (Wong 1983 and 1987, Peterson et al. 1985) have shown that the chemicals applied in the past do, in fact, leach below the root zone, contrary to the original predictions, and can eventually reach the ground water. Experiments designed to characterize the nuances of various processes, such as volatilization, sorption, and degradation, have been conducted recently and will improve the conceptualization of mathematical models in the future.

The EPA's Pesticide Root Zone Model (PRZM), a deterministic-empirical/conceptual fluid flow/solute transport model, has been tested by Loague and co-workers (Loague et al. 1989a, b; Loague 1992) against measured concentration profiles for DBCP and EDB in central Oahu. These simulations illustrate that the chemicals used in the past can indeed move to considerable depths. Models of this kind, once properly validated, can be used to simulate the predicted fate of future pesticide applications. One must always remember, however, that numerical simulations must be interpreted in terms of the limiting assumptions associated with model and data errors.

Ground water vulnerability maps and assessments of their uncertainty were pioneered at the University of Hawaii in the Department of Agriculture Engineering (Khan and Liang 1989, Loague and Green 1990a). These pesticide leaching assessments were made by coupling a simple mobility index to a geographic information system. Loague and coworkers have investigated the uncertainty in these maps owing to data and model errors (Loague and Green 1988; Loague et al. 1989c, 1990; Loague and Green 1990b, 1990c; Loague 1991; Kleveno et al. 1992; Yost et al. 1993). The Hawaiian database on soils, climate, and chemicals is neither perfect nor poor for modeling applications; it is typical of what exists in most states—major extrapolations are required to estimate the input parameters required for almost any chemical fate model.

Sampling from wells in Hawaii has shown the concentrations of various chemicals, both from agriculture and industrial sources, which have leached to ground water in Hawaii. These concentrations, in general, are low compared to the levels detected in other states and for the most part are below health advisory levels established by EPA. In some instances contamination has not resulted from agriculture, but rather from point sources such as chemical loading and mixing areas and possibly from ruptured fuel lines. The widespread presence of trichloropropane (TCP) in Hawaii's ground water and deep soil cores at concentrations higher than DBCP was totally unexpected. TCP was never applied as a pesticide, but results from the manufacture of the fumigant DD, which was used until 1977 in pineapple culture. The occurrence of TCP illustrates that one must be aware of the chemicals applied as well as their components and transformation products.

Wells have been closed in Hawaii even though the measured contaminant concentrations have been below those considered to pose a significant health risk. At municipal well locations in central Oahu, where DBCP, EDB, and/or TCP have been detected, the water is now passed through carbon filters before it is put into the distribution system. The cost of this treatment is passed on to the water users, rather than to those who applied the chemicals.

The pesticide leaching assessment maps developed by Khan and Liang (1989) are intended for incorporation into the regulatory process. Decisions are not made on the basis of the red and green shaded areas for different chemicals (see Plate 3 ), but this information is considered. The uncertainty analysis by Loague and coworkers has shown some of the limitations of deterministic assessments in the form of vulnerability maps and provided initial guidance on data shortfalls.

APPLICATION OF A VULNERABILITY INDEX FOR DECISION-MAKING AT THE NATIONAL LEVEL

Need for a vulnerability index.

A vulnerability index for ground water contamination by pesticides has been developed and used by USDA as a decision aid to help attain the objectives of the President's Water Quality Initiative (see Box 1.1 ). A vulnerability index was needed for use in program management and to provide insight for policy development. Motivation for the development of the vulnerability index was provided by two specific questions:

Given limited resources and the geographic diversity of the water quality problems associated with agricultural production, what areas of the country have the highest priority for study and program implementation?

What policy implications emerge from the spatial patterns of the potential for conamination from a national perspective, given information currently available about farming practices and chemical use in agriculture?

Description of the Vulnerability Index

A vulnerability index was derived to evaluate the likelihood of shallow ground water contamination by pesticides used in agriculture in one area compared to another area. Because of the orientation of Initiative policies to farm management practices, it was necessary that the vulnerability measure incorporate field level information on climate, soils, and chemical use. It also needed to be general enough to include all areas of the country and all types of crops grown.

A Ground Water Vulnerability Index for Pesticides (GWVIP) was developed by applying the Soil-Pesticide Interaction Screening Procedure (SPISP) developed by the Soil Conservation Service to the National Resource Inventory (NRI) land use database for 1982 and the state level pesticide use database created by Resources for the Future (Gianessi and Puffer 1991). Details of the computational scheme and databases used are described by Kellogg et al. (1992). The 1982 NRI and the associated SOIL-5 database provide information on soil properties and land use at about 800,000 sample points throughout the continental United States. This information is sufficient to apply the SPISP to each point and thus obtain a relative measure of the soil leaching potential throughout the country. The RFF pesticide use database was used to infer chemical use at each point on the basis of the crop type recorded in the NRI database. By taking advantage of the statistical properties of the NRI database, which is based on a statistical survey

sampling design, the GWVIP score at each of the sample points can be statistically aggregated for making comparisons among regions.

Since the GWVIP is an extension of a screening procedure, it is designed to minimize the likelihood of incorrectly identifying an area as having a low potential for contamination—that is, false negatives are minimized and false positives are tolerated. The GWVIP is designed to classify an area as having a potential problem even if the likelihood is small.

GWVIP scores were graphically displayed after embedding them in a national cartographic database consisting of 13,172 polygons created by overlaying the boundaries of 3,041 counties, 189 Major Land Resource Areas (MLRAs), 2,111 hydrologic units, and federal lands.

Three caveats are especially important in using the GWVIP and its aggregates as a decision aid:

Land use data are for 1982 and do not represent current cropping patterns in some parts of the country. Although total cropland acreage has remained fairly stable over the past 10 years, there has been a pronounced shift from harvested cropland to cropland idled in government programs.

The approach uses a simulation model that predicts the amount of chemical that leaches past the root zone. In areas where the water table is near the surface, these predictions relate directly to shallow ground water contamination. In other areas a time lag is involved. No adjustment was made for areas with deep water tables.

No adjustment in chemical use is made to account for farm management factors, such as chemical application rates and crop rotations. The approach assumes that chemical use is the same for a crop grown as part of a rotation cropping system as for continuous cropping. Since the chemical use variable in the GWVIP calculation is based on acres of land treated with pesticides, application rates are also not factored into the analysis.

Application to Program Management

By identifying areas of the country that have the highest potential for leaching of agrichemicals, the GWVIP can serve as a basis for selecting sites for implementation of government programs and for more in-depth research on the environmental impact of agrichemical use. These sites cannot be selected exclusively on the basis of the GWVIP score, however, because other factors, such as surface water impacts and economic and demographic factors, are also important.

For example, the GWVIP has been used as a decision aid in selecting sites for USDA's Area Study Program, which is designed to provide chemical use and farming practice information to aid in understanding the relationships among farming activities, soil properties, and ground water quality.

The National Agricultural Statistics Service interviews farm operators in 12 major watersheds where the U.S. Geological Survey is working to measure the quality of surface and ground water resources under its National Water Quality Assessment Program. At the conclusion of the project, survey information will be combined with what is learned in other elements of the President's Water Quality Initiative to assess the magnitude of the agriculture-related water quality problem for the nation as a whole and used to evaluate the potential economic and environmental effects of Initiative policies of education, technical assistance, and financial assistance if implemented nationwide.

To meet these objectives, each Area Study site must have a high potential for ground water contamination relative to other areas of the country. A map showing the average GWVIP for each of the 13,172 polygons comprising the continental United States, shown in Plate 3 , was used to help select the sites. As this map shows, areas more likely to have leaching problems with agrichemicals than other areas of the country occur principally along the coastal plains stretching from Alabama and Georgia north to the Chesapeake Bay area, the corn belt states, the Mississippi River Valley, and the irrigated areas in the West. Sites selected for study in 1991 and 1992 include four from the eastern coastal plain (Delmarva Peninsula, southeastern Pennsylvania, Virginia and North Carolina, and southern Georgia), four from the corn belt states (Nebraska, Iowa, Illinois, and Indiana), and two from the irrigated areas in the West (eastern Washington and southeastern Idaho). Four additional sites will be selected for study in 1993.

Application to Policy Analysis and Development

The GWVIP has also been used by USDA to provide a national perspective on agricultural use of pesticides and the potential for ground water contamination to aid in policy analysis and development.

The geographic distribution of GWVIP scores has shown that the potential for ground water contamination is diverse both nationally and regionally. Factors that determine intrinsic vulnerability differ in virtually every major agricultural region of the country. Whether an impact is realized in these intrinsically vulnerable areas depends on the activities of producers—such as the type of crop planted, chemical use, and irrigation practices—which also vary both nationally and regionally. High vulnerability areas are those where a confluence of these factors is present. But not all cropland is vulnerable to leaching. About one-fourth of all cropland has GWVIP scores that indicate very low potential for ground water contamination from the use of agrichemicals. Nearly all agricultural states have significant acreage that meets this low vulnerability criterion. Areas of the country identified as being in a high vulnerability group relative to potential

for agrichemical leaching also have significant acreages that appear to have low vulnerability.

This mix of relative vulnerabilities both nationally and regionally has important policy implications. With the potential problem so diverse, it is not likely that simple, across-the-board solutions will work. Simple policies—such as selective banning of chemicals—may reduce the potential for ground water contamination in problem areas while imposing unnecessary costs on farming in nonproblem areas. The geographic diversity of the GWVIP suggests that the best solutions will come from involvement of both local governments and scientists with their state and national counter-parts to derive policies that are tailored to the unique features of each problem area.

In the future, USDA plans to use vulnerability indexes, like the GWVIP, in conjunction with economic models to evaluate the potential for solving agriculture-related water quality problems with a nationwide program to provide farmers with the knowledge and technical means to respond voluntarily to water quality concerns.

These six case studies illustrate how different approaches to vulnerability assessment have evolved under diverse sets of management requirements, data constraints, and other technical considerations. In addition, each of these examples shows that vulnerability assessment is an ongoing process through which information about a region's ground water resources and its quality can be organized and examined methodically.

In Iowa, the Iowa DNR staff elected to keep their vulnerability characterization efforts as simple as possible, and to use only properties for which data already existed or could be easily checked. They assumed that surficial features such as the soil are too thin and too disrupted by human activities (e.g., tillage, abandoned wells) to provide effective ground water protection at any particular location and sought to identify a surrogate measure for average travel time from the land surface to the aquifer. Thus, a ground water vulnerability map was produced which represents vulnerability primarily on the basis of depth to ground water and extent of overlying materials. Wells and sinkholes are also shown. The results are to be used for informing resource managers and the public of the vulnerability of the resource and to determine the type of information most needed to develop an even better understanding of the vulnerability of Iowa's ground water.

The Cape Cod approach to ground water vulnerability assessment is perhaps one of the oldest and most sophisticated in the United States. Driven by the need to protect the sole source drinking water aquifer underlying this sandy peninsula, the vulnerability assessment effort has focused on the identification

and delineation of the primary recharge areas for the major aquifers. This effort began with a simple mass balance approach which assumed even recharge within a circular area around each drinking water well. It has since evolved to the development of a complex, particle-tracking three-dimensional model that uses site-specific data to delineate zones of contribution. Bolstered by strong public concern, Cape Cod has been able to pursue an ambitious and sophisticated agenda for resource protection, and now boasts a sophisticated differential management ground water protection program.

In Florida, ground water resource managers rely on a combination of monitoring and vulnerability assessment techniques to identify high recharge areas the develop the state ground water protection program. Overlay and index methods, including several modified DRASTIC maps were produced to identify areas of ground water significance in support of decision making in state land acquisition programs aimed at ground water protection. In addition, several monitoring networks have been established to assess background water quality and monitor actual effects in areas identified as highly vulnerable. The coupling of ground water vulnerability assessments with monitoring and research efforts, provides the basis of an incremental and evolving ground water protection program in Florida.

The programs to protect ground water in California's intensely agricultural San Joaquin Valley are driven largely by compliance with the state Pesticide Contamination Prevention Act. The California Department of Pesticide Regulation determined that no model would be sufficient to cover their specific regulatory needs and that the available data bases were neither suitable nor reliable for regulatory purposes. Thus, a ground water protection program was built on the extensive existing pesticide use reporting system and the significant ground water monitoring requirements of the act. Using farm sections as management units, the state declares any section in which a pesticide or its degradation product is detected as a pesticide management zone and establishes further restrictions and monitoring requirements. Thus, the need to devise a defensible regulatory approach led California to pursue a mechanistic monitoring based approach rather than a modeling approach that would have inherent and difficult to quantify uncertainties.

In contrast, the approach taken in Hawaii involves an extensive effort to understand the uncertainty associated with the assessment models used. The purpose of this is to provide guidance to, but not the sole basis for, the pesticide regulation program. The combined use of sampling, physically-based numerical modeling, and a chemical leaching index has led to extensive improvements in the understanding of the fate of pesticides in the subsurface environment. Uncertainty analyses are used to determine where additional information would be most useful.

Finally, USDA's Ground Water Vulnerability Index for Pesticides illustrates a national scale vulnerability assessment developed for use as a decision aid and analytical tool for national policies regarding farm management and water quality. This approach combines nationally available statistical information on pesticide usage and soil properties with a simulation model to predict the relative likelihood of contamination in cropland areas. USDA has used this approach to target sites for its Area Study Program which is designed to provide information to farmers about the relationships between farm management practices and water quality. The results of the GWVIP have also indicated that, even at the regional level, there is often an mix of high and low vulnerability areas. This result suggests that effective ground water policies should be tailored to local conditions.

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Yost, R.S., K. Loague, and R.E. Green. 1993. Reducing variance in soil organic carbon estimates—soil classification and geostatistical approaches. Geoderma 57(3):247-262

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• Published: 22 June 2021

The widespread and unjust drinking water and clean water crisis in the United States

• J. Tom Mueller   ORCID: orcid.org/0000-0001-6223-4505 1 &
• Stephen Gasteyer 2  

Nature Communications volume  12 , Article number:  3544 ( 2021 ) Cite this article

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An Addendum to this article was published on 13 June 2023

An Author Correction to this article was published on 13 June 2023

Many households in the United States face issues of incomplete plumbing and poor water quality. Prior scholarship on this issue has focused on one dimension of water hardship at a time, leaving the full picture incomplete. Here we begin to complete this picture by documenting incomplete plumbing and poor drinking water quality for the entire United States, as well as poor wastewater quality for the 39 states and territories where data is reliable. In doing so, we find evidence of a regionally-clustered, socially unequal household water crisis. Using data from the American Community Survey and the Environmental Protection Agency, we show there are 489,836 households lacking complete plumbing, 1,165 community water systems in Safe Drinking Water Act Serious Violation, and 9,457 Clean Water Act permittees in Significant Noncompliance. Further, elevated levels of water hardship are associated with rurality, poverty, indigeneity, education, and age—representing a nationwide environmental injustice.

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Introduction

Both in and out of the country, most presume that residents of the United States live with close to universal access to potable water and sanitation. The United Nations Sustainable Development Goals Tracker, which tracks progress toward meeting Sustainable Development Goal Number 6—calling for universal access to potable water and sanitation for all by 2030—estimates that 99.2% of the US population has continuous access to potable water and 88.9% has access to sanitation 1 . By percentages and the lived experience of most Americans, this appears accurate. The American Community Survey shows that from 2014 to 2018 only an estimated 0.41% of occupied US households lacked access to complete plumbing—meaning access to hot and cold water, a sink with a faucet, and a bath or shower. Although this relative percentage may be low, this 0.41% corresponds to 489,836 households spread unevenly across the country, making the absolute number quite troubling. These numbers become even more dramatic when we broaden our scope to poor household water quality, where the estimates we provide in this paper show the issue affects a far greater share of the population (Table  1 ).

This study builds on a growing body of evidence showing access to plumbing, water quality, and basic sanitation are lacking for a disturbingly large number of US residents by providing a definitive picture of the ongoing household water crisis in the United States. Water and sanitation issues have been a growing concern in the United States, particularly among policy organizations, for the past 20 years 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 . For example, the now-dated Still Living without the Basics report used Census data from 2000 to show that more than 670,000 households (0.64% of households and 1.7 million people) lacked access to complete plumbing facilities 7 . Further, the Water Infrastructure Network published a report in 2004 citing a gap of $23 billion between available funding and needed water and sanitation infrastructure investments 6 . In line with this, the American Society of Civil Engineers has repeatedly given the United States a “D” grade for water infrastructure, and “D-” for wastewater infrastructure in their annual “Infrastructure Report Card” 11 . Although water hardship in the United States has experienced some academic attention, much of the work has become dated and has generally focused on a single dimension of the issue at a time—for example, recent scholarship has focused on exclusively incomplete plumbing 3 , 4 , 9 , water quality 5 , 10 , or on only urban parts of the country 2 . This has left our understanding of the scope of the issue incomplete. In this paper, we estimate and map the full scope of water hardship for the dimensions of incomplete plumbing and poor drinking water quality across the entire United States, while also estimating and mapping the scope of poor wastewater quality for the 39 states where EPA data is reliable, in order to complete this picture.

Prior work from academics and policy groups on dimensions of water hardship has found water access issues pattern along common social inequalities in the United States. The Natural Resources Defense Council released a report demonstrating the disproportionate impact on people of color posed by Safe Drinking Water and Clean Water Act regulatory burdens 12 , which built on similar peer reviewed findings 13 , 14 . Furthermore, both policy papers and peer reviewed studies have analyzed Census data to estimate the population lacking access to complete plumbing facilities and clean water 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 12 . The studies suggest low-income and non-White people—particularly indigenous populations who continue to face injustices related to legacies of settler colonialism 15 —are significantly more likely to have incomplete plumbing and unclean water 3 , 12 . Further, it appears incomplete plumbing may be a disproportionately rural issue, while poor water quality may be a disproportionately urban issue 5 , 9 . Direct comparisons, as we perform here, are needed to fully establish the variability of this inequality between dimensions of water hardship.

The prior scholarship on the inequitable distribution of plumbing and pollution speaks to the well-documented environmental injustices found throughout the United States. Environmental injustice, meaning the absence of “fair treatment and meaningful involvement of all people regardless of race, color, national origin, or income with respect to the development, implementation, and enforcement of environmental laws, regulations, and policies” (p. 558) 16 , has been documented in the United States along the social dimensions of income 17 , 18 , poverty 19 , race and ethnicity 20 , 21 , age 22 , education 22 , 23 , and rurality 22 , 24 , 25 . Based on the evidence of prior work on water hardship, it is clear household water access represents an ongoing environmental injustice in the United States 5 . However, the specific dimensions of this injustice, and how they vary between type of water hardship remain largely unknown. To address this gap, we estimate models of water injustice for the previously identified social dimensions at the county level for elevated levels of both incomplete plumbing and poor water quality.

Level of water hardship in the United States

Based upon the most recent available data reported by both the United States Census Bureau via the American Community Survey and the Environmental Protection Agency via Enforcement and Compliance History Online, we find that incomplete plumbing and poor water quality affects millions of Americans as of 2014–2018 and August 2020, respectively (Table  1 ) 26 , 27 . A total of 0.41% of households, or 489,836 households, lacked complete plumbing from 2014–2018 in the United States. Further, 509 counties, representing over 13 million Americans, have an elevated level of the issue where >1% of household do not have complete indoor plumbing (Table  2 ). Thus, even if individuals are not experiencing the issue themselves, they may live in a community where incomplete plumbing is a serious issue.

The portion of the population affected by poor water quality is much greater than that of incomplete plumbing. Poor water quality in our analysis is indicated in two ways, (1) Safe Drinking Water Act Serious Violators and (2) Clean Water Act Significant Noncompliance. For the first, community water systems are regulated under the Safe Drinking Water Act and are scored based on their violation and compliance history, those community water systems that are the most problematic are recorded as Serious Violators by the Environmental Protection Agency 27 . Second, any facility that discharges directly into waters in the United States is issued a Clean Water Act permit. Those which “hold a more severe level of environmental threat” are ruled as being in Significant Noncompliance 27 . Importantly, although data on Safe Drinking Water Act Serious Violators is available nationwide, the Clean Water Act data reported by the EPA is known to be inaccurate for 13 states. Thus, although we can draw national conclusions for incomplete plumbing and Safe Drinking Water Act violations, our understanding of Clean Water Act violations is limited to the 39 states and territories for which data are available and reliable.

Using these two measures of poor water quality, we find 2.44% of community water systems, a total of 1165, were Safe Drinking Water Act Serious Violators and 3.37% of Clean Water Act permittees in the 39 states and territories with accurate data (see Methods for more details), a total of 9457, were in Significant Noncompliance as of 18 August 2020. At the county level, this corresponds to an average of 2.86% of county community water systems being listed as Safe Drinking Water Act Significant Violators and an average of 6.23% of county Clean Water Act permittees being listed as Significant Noncompliers. Due to limitations in the data, we are unable to determine exactly how many individuals are linked to each problematic community water system or Clean Water Act permittee, however, we do find that over 81 million Americans live in counties where >1% of community water systems are listed as Significant Violators, and more than 153 million Americans in the 39 reliable states and territories live in counties where greater than one percent of Clean Water Act permittees are Significant Noncompliers. Thus, although the number of individuals impacted by these issues is certainly far smaller than these totals, a vast number of Americans live in communities where issues of water quality are elevated.

Due to our conservative approach of removing all states with Clean Water Act data issues, we test the sensitivity of our estimates by also calculating supplemental estimates of Clean Water Act Significant Noncompliance under two counterfactual scenarios. In the first, we include the data as-is from the EPA for all counties in the 50 states, DC, and Puerto Rico, and in the second, we duplicate the counties in the top and bottom 20% of Significant Noncompliance in states without data issues—with the rationale being that the 945 counties removed due to poor data represented roughly 40% of the total counties remaining when problems states were removed. Thus, this attempts to simulate total counts if those removed were balanced between very high and very low levels of noncompliance. Results using all EPA data increase national estimates of Significant Noncompliance (Tables 3 and 4 ), with the total percent of permittees in this status jumping from 3.37% to 6.01%. While the duplication test does raise our estimates, it is not nearly as dramatic, with the percent of permittees in Significant Noncompliance only rising to 3.87%. These results make sense given that the most common reason for data issues was an overreporting of noncompliance within states.

When looking at the issue spatially, we can see that while water hardship affects all parts of the country to some degree, the issues are clustered in space (Figs.  1 – 3 ). Importantly, the clustering varies between each water issue. Incomplete plumbing is clustered in the Four Corners, Alaska, Puerto Rico, the borderlands of Texas, and parts of Appalachia (Fig.  1 ); Safe Drinking Water Act Serious Violators are clustered in Appalachia, New Mexico, Alaska, Puerto Rico, and the Northern Intermountain West (Fig.  2 ); and Clean Water Act Significant Noncompliance clearly follows state boundaries—likely speaking to variable monitoring by state. Although spatial representation is limited by the absence of 13 states with inaccurate EPA data, we can still see that Clean Water Act Significant Noncompliance is clustered in the Intermountain West, the Upper Midwest, Appalachia, and the lower Mississippi (Fig. 3 ). These regional clusters persist when we include the problem states, which is visible in the map included in the Supplemental Information (Supplementary Figure 1 ).

Households are determined to have incomplete plumbing if they do not have access to hot and cold water, a sink with a faucet, a bath or shower, and—up until 2016—a flush toilet.

Safe Drinking Water Act Serious Violators are those community water systems regarded by the Environmental Protection Agency as the most problematic due to violation and compliance history.

All facilities that discharge directly into water of the United States are issued a Clean Water Act permit, those who represent a more severe level of environmental threat due to violations and noncompliance are considered in Significant Noncompliance.

Water injustice modeling

Although we can easily see clustering by space in Figs.  1 through 3 , the maps do not tell us whether or not incomplete plumbing and poor water quality are also clustered by social dimensions, which would represent an environmental injustice. To assess this social clustering, we estimate linear probability models of elevated levels of incomplete plumbing and poor water quality with the previously identified environmental justice dimensions of age, income, poverty, race, ethnicity, education, and rurality as our independent variables. We include these independent variables due to their prevalence within prior work on environmental injustice in both rural and urban areas 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 . Further, although there is not a one-to-one overlap, these variables conceptually map onto the dimensions of the Center for Disease Control Social Vulnerability Index: Socioeconomic Status (i.e. income, poverty, education), Household Composition & Disability (i.e. age), Minority Status & Language (i.e. race and ethnicity), and Housing & Transportation (i.e. rurality) 28 .

For each outcome, we first estimate purely descriptive models with only one dimension of injustice included at a time, and then estimate a full model with all dimensions included. The outcomes are dichotomous measures of whether or not a county had >1% of households with incomplete plumbing, >1% of community water systems listed as Serious Violators, or >1% of Clean Water Act permittees in Significant Noncompliance. All descriptive statistics for the dichotomous outcomes are presented in Table 2 . Descriptive statistics for the continuous independent variables are presented in Supplementary Information (Supplementary Table  1 ). Here we present the outcomes of the purely descriptive models visually in Fig.  4 and discuss the full models in the narrative. Full regression results, including exact 95% confidence intervals and p -values, for all models are available in Supplementary Information (Supplementary Tables  2 , 3 and 4 ).

Different colors for plotted coefficients represent separate blocks of variables. Models are linear probability models with state fixed effects and cluster-robust standard errors at the state level. All tests two-tailed. Dots indicate point estimates and lines represent 95% confidence intervals. Models predicted elevated levels of each dimension of water hardship. For incomplete plumbing this is indicated by >1% of households in a county having incomplete plumbing ( N  = 3219). For Safe Drinking Water Act (SDWA) Serious Violation this is indicated by >1% of active community water systems being considered Serious Violators ( N  = 3143). For Clean Water Act (CWA) Significant Non-Compliance this is indicated by >1% of Clean Water Act permittees being considered in Significant Non-Compliance ( N  = 2261). Full model results, confidence intervals, and exact p -values available in SI.

We find elevated levels of incomplete plumbing at the county level were significantly ( p  < 0.05) associated with older populations, lower income, higher poverty, greater portions of indigenous people (American Indian, Alaska Natives, Native Hawaiian, and Other Pacific Islanders), lower levels of education, and more rural counties (Fig.  4 ). A great deal of these associations persisted in a full model with all dimensions of injustice (Supplementary Table  2 ). The only differences between the full model and the series of purely descriptive models were that income, percent with at least a bachelor’s degree, and non-metropolitan metropolitan adjacency were no longer significantly associated with elevated levels of incomplete plumbing. This indicates that the inequalities in plumbing access along the dimensions of age, poverty, indigeneity, low education, and extreme rurality persist at the county level, even when accounting for the other dimensions of environmental injustice.

The models for elevated levels of Safe Drinking Water Act Serious Violators indicated less social inequality than the models for incomplete plumbing. The purely descriptive models found elevated levels of Serious Violators were associated with higher income, higher poverty, and metropolitan counties (Fig.  4 ). The full model had minor variation, with median household income no longer being significant in the model (Supplementary Table  3 ). Thus, the full model shows that the association between elevated levels of Serious Violators and higher poverty and metropolitan status persists even when considering other social dimensions.

We see the fewest indicators of water injustice for elevated levels of Clean Water Act Significant Noncompliance—which only include counties within the 39 states and territories with accurate data. In the purely descriptive models, we find older populations, more Latino/a counties, less educated counties, and remote rural counties were significant less likely to have elevated levels of noncompliance (Fig. 4 ). In the full model, the association for education is no longer significant but age, Latino/a, and rurality remain (Supplementary Table 4 ). Similar to our national estimates, we also conducted model sensitivity tests using the same scenarios described above. As shown in Fig. 5 , neither scenario substantively changes our conclusions, with the only changes in significance being for percent Latino/a and percent without a high school diploma—both of which were only marginally significant in our primary models ( p  > 0.01).

Descriptive regression model results. Different colors for plotted coefficients represent separate blocks of variables. Models are linear probability models with state fixed effects and Huber/White/Sandwich cluster-robust standard errors at the state level. All tests are two-tailed. Dots indicate point estimates and lines represent 95% confidence intervals. Models predicted whether or not there were greater than 1% of Clean Water Act permittees being considered in Significant Noncompliance in the county. First model excludes counties in states with CWA data issues ( N  = 2261), second model includes all counties reported by the EPA ( N  = 3206), third model duplicates counties in the top and bottom 10% of CWA Significant Noncompliance within states without data issues ( N  = 3151). Full model results, confidence intervals, and exact p values available in SI.

Our findings demonstrate that the problem of water hardship in the United States is hidden, but not rare. Indeed, millions live in counties where more than 1 out of 100 occupied households lack complete plumbing. Millions more live in places with chronic Safe Drinking Water Act violations and Clean Water Act noncompliance. We present this paper to help sound the alarm of this significant household water crisis in the United States. Although the relative share of Americans experiencing this problem is low, the absolute number of people dealing with incomplete plumbing—a total of 489,836 households—and poor water quality—1165 community water systems nationwide and 9457 Clean Water Act permittees in the 39 accurate states and territories—remains quite high. Further, given the water infrastructure of the United States, consistently deemed as poor by experts 6 , 11 , if action is not taken the situation may only get worse.

These findings are even more concerning when considering that water hardship is spread unevenly across both space and society, reflecting the spatial patterning of social inequality due to settler colonialism, racism, and economic inequality in the United States. Figures  1 , 2 , and 3 document the clear regional clustering of these issues and our models of environmental injustice demonstrate the social inequalities found for this form of hardship. Particularly in the case of incomplete plumbing, we find significant environmental injustice at the county level along the social dimensions of age, income, poverty, indigeneity, education, and rurality. These associations certainly stem from multiple causal pathways—for example associations with indigeneity likely stem from legacies of injustice as well as ongoing policies placing limitations on land use and infrastructure development on American Indian reservations 15 . Remedying these injustices will require careful attention to the root causes of the problem. It is important to note that the signs of injustice for poor water quality were less clear than for incomplete plumbing, with far fewer significant associations. Further, the minimal support for injustice in the case of Clean Water Act Significant Noncompliance was evident in all three specifications of counties in our sensitivity tests. Suggesting that the removal of the states with data issues did little to impact coefficient estimates. These differences between dimensions of water hardship highlight the nuance between each of these specific forms of water hardship, and suggest a one-size-fits-all approach to remedying this crisis is unlikely to be effective. This need for place-based policy is made stark when we view the obvious state level differences in Clean Water Act Significant Noncompliance in Fig. 3 . A clear direction for future work is to investigate the cause of these notable state-level differences.

The household water access and quality crisis we have identified here is solvable. Policy is needed to specifically address these issues and bring this problem into the spotlight. However, as indicated by the persistently high levels of Safe Drinking Water Act Serious Violation and Clean Water Act Significant Noncompliance, any policy put in place must be enforceable and strong. As it currently stands, counties with elevated levels of incomplete plumbing and poor water quality in America—which are variously likely to be more indigenous, less educated, older, and poorer—are continuing to slip through the cracks.

Data sources

Data for this analysis were extracted from the American Community Survey (ACS) 5-year estimates for 2014–2018 via Integrated Public Use Microdata Series – National Historic Geographic information System (IPUMS-NHGIS) 26 , and from the Environmental Protection Agency’s (EPA) Enforcement and Compliance History Online (ECHO) Exporter 27 . Data were extracted at the county level for all 50 states, Washington DC, and Puerto Rico–the two non-state entities with available data. The ACS is an ongoing survey of the United States which documents a wide variety of social statistics ranging from simple population counts to housing characteristics. Due to the staggered sampling structure of the ACS, it takes 5 years for every county to be sampled. Because of this, researchers must use 5-year intervals to ensure complete data coverage. The data from these 5 years are projected into estimates for all counties in the United States for the 5-year period in question. As of this study, 2014–2018 was the most recently available data.

ECHO collates data from EPA-regulated facilities across the United States of America to report compliance, violation, and penalty information for all facilities for the most recent 5-year interval. ECHO data is updated weekly and the data for this paper was extracted on 18 August 2020. This means that the data in our analysis represents the status of each community water system or Clean Water Act permittee, as reported by the EPA, as of 18 August 2020. Only those community water systems or Clean Water Act permittees listed as Active by ECHO were included in this analysis. As ECHO data is at the level of the water system, permittee, or utility, we aggregated data up to the county level.

Safe Drinking Water Act data was geolocated using QGIS 3.10 based upon latitude and longitude. This was done because other geographic identifiers for the Safe Drinking Water Act data were often missing. In line with prior work 4 , 5 , 7 , 8 , and in order to facilitate a cleaner dataset, we only focus on those water systems labeled community water systems for our analysis. Community water systems were geolocated based upon the county in which their latitude and longitude were located, if a community water system had latitude and longitude over water, a nearest neighbor join was used. In total, 1334 out of 49,479 community water systems were dropped because of there being no reported latitude or longitude. Of these, a total of 4.0%, or 54 community waters systems, were reported as in serious violation. It should be noted that the EPA is aware of a small number of water systems in Washington for which ECHO data may be inaccurate. However, since this is a small number and it is not listed as a ‘Primary Data Alert,’ we retain all states in this portion of the analysis. Finally, the EPA is generally aware that there are “inaccuracies and underreporting of some data in this system,” which is listed as a Primary Data Alert 27 . However, due to the lack of specifics, we cannot exclude inaccurate cases. Thus, our analysis should be viewed as reflecting drinking water quality is as reported by the EPA in August of 2020, which may reflect some level of inaccuracy.

Active Clean Water Act permittees were first identified by listed county. This was done because 345,176 out of 350,476 permittees had a county reported. Those without a county reported were located using latitude and longitude in the same manner as community water systems. There were 10 permittees without latitude and longitude or county listed which were excluded from our analysis. Of these, seven were in significant noncompliance and three were not. Due to some Clean Water Act permittees having latitude and longitude placements far away from the United States, those over 100 km from their nearest county were excluded from analysis. Unfortunately, ECHO data for the Clean Water Act data during the study period is inaccurate for 13 states. Although the nature of the inaccuracy varies from state to state, these issues generally stem from difficulties in transferring state data into the federal system. Due to this, these states appear to have far more permittees in Significant Noncompliance than are actually in violation. To address this issue, we removed all counties within these states from our Clean Water Act analysis. The impacted states include Iowa, Kansas, Michigan, Missouri, Nebraska, North Carolina, Ohio, Pennsylvania, Vermont, Washington, West Virginia, Wisconsin, and Wyoming 29 . Finally, for community water systems and Clean Water Act permittees, some counties (76 for community water systems and 5 for Clean Water Act permittees) had no reported cases. Those counties were treated as zeroes for cartography and as missing for modeling purposes.

Similar to prior work in this area 4 , 5 , 8 , we restrict our analysis to the scale of the county for reasons related to data limitations and resulting conceptual validity. Although counties are arguably larger in geographic area than ideal for an environmental injustice analysis, if we were to use a smaller unit for which data is available such as the census tract, the conceptual validity of the analysis would be limited due to the apolitical nature of these units. As outlined above, ECHO data is messy and missing many geographic identifiers. What is provided is generally either the county or latitude and longitude. If only the county is provided, then we are constrained to using the county regardless of conceptual validity. However, even when latitude and longitude are provided—which is the case for many observations—the provided point location says nothing about which households the water system or permittee serves or impacts. Due to this, whatever geographic unit we use carries the assumption that those in the unit could be plausibly impacted by the water system or permittee. Given that counties are often responsible for both regulating drinking water, as well as maintaining and providing water infrastructure 30 , we were comfortable with this assumption between point location and presumed spatial impact when using the scale of the county. However, we believe this assumption would have been invalid and untestable for smaller apolitical units for which demographic data is available such as census tracts.

Beyond the issues presented by ECHO data, the county is also the appropriate scale of analysis for this study due to the estimate-based nature of the ACS. ACS estimates are based on a rolling 5-year sample structure and often have very large margins of error. At the census tract level, these standard errors can be massive, especially in rural areas 31 , 32 , 33 . Due to this variation, and the need to include all rural areas in this analysis, the county, where the margins of error are considerably smaller, is the appropriate unit for this study. All of this said, the county is, in fact, a larger unit than often desired or used in environmental justice studies. Studies focused on exclusively urban areas with clearer pathways of impact can and should use smaller units such as census tracts. It will be imperative for future scholarship focused on water hardship across the rural-urban continuum to gain access to reliable data on sub-county political units, as well as data linking water systems to users, to continue documenting and pushing for water justice.

Dependent variables

The dependent variables for this analysis were assessed in both a continuous and dichotomous format. For descriptive results and mapping, continuous measures were used. For models of water injustice, a dichotomous measure which classified counties as either having low levels of the specific water issue or elevated levels of the specific water issue, was used due to the low relative frequency of water access and quality issues relative to the whole United States population. For all three outcomes, we benchmark an elevated level of the issue as what would be viewed as an unacceptable level under United Nations Sustainable Development Goal 6.1, which states, “by 2030 achieve universal and equitable access to safe and affordable drinking water for all” 1 . As this goal focuses on ensuring all people have safe water, we deem a county as having an elevated level of the issue if >1% of households, community water systems, or permittees had incomplete plumbing, were in Significant Violation, or Significant Noncompliance, respectively. Although we could have used an even stricter threshold given the SDG’s emphasis on ensuring access for all people, we use 1% as our cut-off due to its nominal value and ease of interpretation.

For water access, the continuous measure was the percent of households in a county with incomplete household plumbing as reported by the ACS. The ACS currently asks respondents if they have access to hot and cold water, a sink with a faucet, and a bath or shower. Up until 2016, the question also included a flush toilet 34 . As we must use the most recent 2014–2018 5-year estimates to establish full coverage of all counties, this means that incomplete plumbing in this item may, or may not include a flush toilet depending on when the specific county was sampled. The dichotomous version of this variable benchmarked elevated levels of incomplete plumbing as whether or not 1% or more of households in a county had incomplete plumbing.

Water quality was assessed via both community water systems from the Safe Drinking Water Act, and from permit data via the Clean Water Act. For Safe Drinking Water Act data, the continuous measure was the percent of community water systems within a county classified as a Safe Drinking Water Act Serious Violator at time of data extraction. The EPA assigns point values of either 1, 5, or 10 based upon the severity of violations of the Safe Drinking Water Act. A Serious Violator is one who has “an aggregate score of at least eleven points as a result of some combination of: unresolved more serious violations (such as maximum contaminant level violations related to acute contaminants), multiple violations (health-based, monitoring and reporting, public notification and/or other violations), and/or continuing violations” 27 . The dichotomous measure benchmarked elevated rates of Safe Drinking Water Act Significant Violation as whether or not >1% of county community water systems were classified as Serious Violators.

For Clean Water Act permit data, the continuous measure was the percent of permit holders listed as in Significant Noncompliance at the time of data extraction. Significant Noncompliance in the Clean Water Act refers to those permit holders who may pose a “more severe level of environmental threat” and is based upon both pollution levels and reporting compliance 27 . The dichotomous measure again set the threshold for elevated levels of poor water quality at whether or not >1% of Clean Water Act permittees in a county were listed as in Significant Noncompliance at time of data extraction.

Independent variables

The independent variables we include in models of water injustice are those frequently shown to be related to environmental injustice in the United States. These include age, income, poverty, race, ethnicity, education, and rurality 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 . Age was included as median age. Income was included as median household income. Poverty was the poverty rate of the county as determined by the official poverty measure of the United States 35 . Race and ethnicity was included as percent non-Latino/a Black, percent non-Latino/a indigenous, and percent Latino/a. Because the focus was on indigeneity, percent American Indian or Alaska Native was collapsed with Native Hawaiian or Other Pacific Islander. We did not include percent non-Latino/a white due to issues of multicollinearity. Finally, rurality was included as a three-category county indicator of metropolitan, non-metropolitan metropolitan-adjacent, and non-metropolitan remote, as determined by the Office of Management and Budget in 2010 36 . The OMB determines a county is metropolitan if it has a core urban area of 50,000 or more people, or is connected to a core metropolitan county by a 25% or greater share of commuting 36 . A non-metropolitan county is simply any county not classified as metropolitan. Non-metropolitan metropolitan adjacent counties are those which immediately border a metropolitan county, and non-metropolitan remote counties are those that do not.

Water injustice modeling approach

Water injustice was assessed by estimating linear probability models for the three dichotomous outcome variables with state fixed effects to control for the visible state level heterogeneity and differences in policy, reporting, and enforcement (e.g. the clear state boundary effects in Fig.  3 ). We employ the conventional Huber/White/Sandwich cluster-robust standard errors at the state level—which account for heteroskedasticity while also producing a consistent standard error estimate in-light of the lack of independence found between counties in the same state. All modeling was performed in Stata 16.0 and mapping was performed in QGIS 3.10. We assessed all full models for multicollinearity via condition index and VIF values and the independent variables had an acceptable condition index of 5.48 for incomplete plumbing and Safe Drinking Water Act models and 5.63 for Clean Water Act models, well below the conservative cut-off of 15, as well as VIF values of <10. We initially included percent non-Latino/a white as an independent variable, but removed the item due to unacceptably high condition index levels (>20). All indications of statistical significance are at the p  < 0.05 level and 95% confidence intervals and exact p -values of all estimates are provided in Supplementary Information. Each dependent variable was analyzed through a series of six models. First, we estimated separate purely descriptive models, where the only independent variables included were those associated with that specific dimension and the state fixed effects, for all five dimensions of environmental injustice. After estimating these five models, we estimated a full model including all social dimensions at once.

The reason for this approach was to ensure that we provided a robust descriptive understanding of the on-the-ground social patterns of water hardship, in addition to a full model showing the strongest social correlates of this issue. For example, if when we only included income variables we found that incomplete plumbing is less likely in counties with higher median incomes, but this effect goes away when we include other social variables, this does not remove the fact that there is an unequal distribution of incomplete plumbing by income on-the-ground. All that it means is that this income effect does not persist over and above the other social dimensions of environmental injustice. It may be that once other dimensions such as structural racism, captured by race and ethnicity variables, are considered, income is no longer a significant predictor. However, at a pure associational level, incomplete plumbing would still be unequally distributed by income on-the-ground. In fact, this is exactly what we find for incomplete plumbing (Supplementary Table  2 ). Due to this, both the pure descriptive and full models are needed for full understanding. Complete tables of all results are presented in the Supplementary Information File (Supplementary Tables  1 through 4 ).

Sensitivity tests

Due to our conservative approach to remove all problem states from the Clean Water Act portion of our analysis, we conducted a series of sensitivity tests wherein we generated national estimates of Significant Noncompliance, as well as models of elevated Significant Noncompliance under two scenarios (Supplementary Tables 5 and 6 ). In the first scenario we include all data reported by the EPA, meaning that we use all data for the 50 states, DC, and Puerto Rico, regardless of any EPA data flags. In the second scenario, we replaced the data lost when dropping states by duplicating the counties in the top and bottom 20% of significant violations in the remaining counties. The top and bottom 20% was chosen because the 945 counties removed when the 13 states were dropped was roughly equal to 40% of the remaining 2262 counties. This counterfactual allows us to get closer to a plausible estimate of the absolute scope of CWA Significant Noncompliance by adopting a scenario where the counties dropped in problem states were either very high, or very low in terms of Significant Noncompliance. Functionally, duplicating the bottom 20% posed a challenge because the bottom 30% of counties had zero permittees in Significant Noncompliance. This zero-bias is one of the primary reasons why our outcome variable was dichotomized. To address this, we randomly selected two-thirds of these counties for duplication using a seeded pseudorandom number generator in Stata. Following duplication of cases, all estimates and models were generated in the same manner as the primary models of this study.

Reporting summary

Further information on research design is available in the  Nature Research Reporting Summary linked to this article.

Data availability

The raw and geolocated datasets are publicly available on the Open Science Framework project for this study at https://doi.org/10.17605/OSF.IO/ZPQR9 ( https://osf.io/zpqr9/ ).

Code availability

Analysis code is available on the Open Science Framework project for this study at https://doi.org/10.17605/OSF.IO/ZPQR9 ( https://osf.io/zpqr9/ ). As the raw data was not geolocated using a code-based operation, code for this portion of the analysis is not available. However, the raw data is posted, and should researchers wish they will be able to use our description provided here to replicate geolocation using the GIS software of their choice. All other elements of the analysis are easily replicated via our provided code. As the both the raw and geolocated datasets are provided, replication of our analysis should be straightforward.

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Acknowledgements

The authors would like to acknowledge Tom Dietz, Lauren Mullenbach, Matthew Brooks, and Jan Beecher for their feedback on this manuscript. They would also like to thank Colleen Keltz at the Washington State Department of Ecology for alerting us to the issues with Clean Water Act data for Washington and other states.

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Conceptualization: J.T.M. and S.G.; methodology: J.T.M.; formal analysis: J.T.M.; data curation: J.T.M.; writing- original draft preparation: J.T.M. and S.G.; writing – review and editing: J.T.M. and S.G.; visualization: J.T.M.

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Mueller, J.T., Gasteyer, S. The widespread and unjust drinking water and clean water crisis in the United States. Nat Commun 12 , 3544 (2021). https://doi.org/10.1038/s41467-021-23898-z

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Claire Chadwick; Lauren Maurizio; Robin Humphreys; and Vijay Vulava

The Hanford Nuclear Site

In this section, we will focus on the history of groundwater contamination at the Hanford Nuclear site and assess if there is a danger to communities living downstream from this site. The Hanford Nuclear site in eastern Washington state on the banks of the Columbia River was the first plutonium processing plant in the world and was created during the second world war. Over the next several decades, they continued to produce plutonium for nuclear bombs before the eventual decommissioning bomb manufacturing. However, decades of operation left behind a legacy of highly contaminated groundwater, which includes dangerous levels of radionuclides and toxic chemicals. In this section, we will focus on the history of the site and the extent of groundwater contamination and assess if there is a danger to communities living downstream from this site. Use the information provided to learn more about the extent of the problem.

Watch the video at the link below. Take notes about the details and will be helpful for the questions below.

Exercise 6 – Hanford Site

Use the resources below to answer the following questions:

• The Site overview is provided by the WA Department of Ecology at https://bit.ly/3bxnetk .
• Wikipedia provides a great summary and additional details at https://bit.ly/3rrO8bD .
• Virtual tour of the B Reactor and the Hanford Site (look for it at left-most reactor adjacent to the Columbia River) where the first atomic bomb was manufactured: Hanford Virtual Tour

• Where is the Hanford Site located?
• How large is this site in the area?
• What was the main reason this site was created?
• Which major river is located next to the Hanford Site?
• When did the operations begin at the Hanford Site?
• The Hanford Site is still producing plutonium. T/F
• According to the video, how much waste was discharged into the soils at this site?
• Identify four radioactive elements that leaked from the underground storage tanks into the groundwater.
• Identify the two toxic chemicals (not radioactive elements) that leaked from the underground storage tanks into the groundwater.
• The extent of groundwater contamination at the site is decreasing. T/F
• Explain the reason for this.
• According to the Department of Energy (the video producer), groundwater contamination is not a threat to the Columbia River. T/F
• What is your opinion based on what you learned so far?
• There is a significant groundwater contaminant plume in the center of the site. What is the name of the method being employed to clean up the contaminated groundwater?
• How much groundwater has been cleaned up at the time of this video production?
• How much high-level waste was stored in the underground storage tanks?
• What is the primary pathway from these leaking tanks to the Columbia River?
• How much is the site cleanup expected to cost?
• Using the small map overview in the upper right corner of Figure 1, cities (The Dalles, Portland, etc.) that are downstream of this site are at risk. T/F
• Explain your answer.
• Figure 4 shows the plume of iodine-129 (a long-lived radioactive element) into the year 3890. Is a decline in groundwater contamination expected?

Environmental Geology Laboratory Copyright © 2021 by Claire Chadwick; Lauren Maurizio; Robin Humphreys; and Vijay Vulava is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License , except where otherwise noted.

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La vague n°72, remote audit.

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• Contamination Control Strategy: practices & a case study of a CCS implementation
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Contamination Control Strategy: practices & a case study of a CCS implementation.

As a result of the successive revisions to the draft EU GMP Annex 1 (1) , the term “Contamination Control Strategy (CCS)” has become as well known as the term “Quality Risk Management (QRM),” which is intriguing because the CCS foundation is built on QRM principles.

Since the release of the first EU GMP Annex 1 draft, many questions have been raised by manufacturers and industry associations to the Inspectors Working Group (IWG) regarding the CCS expectations:

• What is the CCS scope – viable and non-viable particulates from any origin (product residue, viruses, disinfectant residues, etc.)?”
• Should the CCS be a document, for example, a “sterility assurance quality manual” that includes an exhaustive list of expectations listed in the latest draft?
• Should manufacturers create a standalone document per site or per production buildings that describes how the strategy is applied and how the performance is measured and evaluated?

These types of questions have led the IWG to include the CCS definition in the glossary of the draft Annex 1 version 12, released in February 2020. “A planned set of controls for microorganisms, pyrogens, and particulates, derived from current product and process understanding that assures process performance and product quality. The controls can include parameters and attributes related to the active substance, excipient and drug product materials and components, facility and equipment operating conditions, in-process controls, finished product specifications, and the associated methods and frequency of monitoring and control” (1) .

Despite the second revision of the draft Annex 1 v12 by IWG, it appears that the need for additional practical guidance for establishing and documenting an appropriate CCS is considered necessary by our industry. Therefore, many technical and scientific industry associations (such as PHSS/A3P, ECA, PDA, ISPE) are working actively to publish CCS practical guideline to assist the industry.

This article is part of a series of articles that will cover CCS practices, development, implementation and evaluation. This first article will discuss CCS practices and a case study of a CCS implementation. The first section presents the results of a survey conducted by STERIS to assess the scope, implementation status, and implementation needs of CCS. The second section provides a real-world example of the key elements of an existing contamination control program, and how this program was upgraded to a CCS based on a gap assessment of the existing program versus the expectations laid out in the latest EU GMP Annex 1 draft v12.

1. Contamination Control Strategy Implementation Status and Practices

In April 2021, a survey was initiated during a STERIS hosted webinar titled “Contamination Control Strategy: Implementation Roadmap” to understand the (bio)pharmaceutical CCS implementation status, practices, and needs. One hundred ninety-one attendees located across the globe participated in the webinar (Figure 1- top and bottom). Only responses from pharmaceutical industry (i.e.: pharmaceutical, biopharmaceutical, medical, industrial, research, consumer) who responded to the survey were considered for the purpose of this analysis; the responses rate varied between 42 to 52% of the total participant.

The majority of respondents work downstream (e.g., formulation, filling, and packaging) and medical devices. The remaining respondents work in upstream (e.g., bulk, drug substance manufacturing) , small molecules, and cell & gene therapy or advanced therapeutic medicinal products (Figure 2).

40% of the respondents see that the biggest challenge in designing a CCS is identifying all the critical controls. In comparison, 22% consider as challenging to identify the interlink between controls (Figure 3 – top). Some (18%) believe that the significant challenge is to define the CCS scope. The challenges expressed by the respondents seem to be the same across the different types of manufacturers.

60% of the respondents are implementing a CCS, despite various challenges identified and Annex 1 being a draft. However, 29% are still in the information-gathering stage or waiting for Annex 1 to go into effect (Figure 4).

Most respondents (81% or 77) would apply the CCS to the manufacturing processes and facilities. In comparison, 7% (or 7) have also included the distribution processes where contamination may occur. The rest (12% or 11) have not defined where the CCS would be applied. It should be noted that the distribution includes transportation of intermediate or finish products between affiliates’ sites or to a contract manufacturer before or after release of the final medicinal product.

71% (or 77) have already defined the scope of their CCS, while the rest, 19% (or 18), have not yet defined it. of those who have already defined the CCS scope, 55% focus on contaminants from microorganisms, particulates, and pyrogens, while 26% focus only on microorganisms and particulates (Figure 5).

The contamination definition in the draft Annex 1 version 12 seems not to include viruses or other types of contaminations (e.g., TSE/BSE under the EMA note for guidance EMA/410/01). However, suppose viruses are identified as a source of contamination, the CCS scope should at least address this risk of contamination and how to prevent contamination.

The term particulate with respect to the CCS scope is currently subject of intense debate as some have included product residue as per EU Annex 15 in their “particulates’ ‘ definition. Therefore, they have included the concept of cross-contamination in their CCS scope. On the other hand, others argue that the definition of “contamination” in the draft Annex 1 glossary deals with foreign particulate matter (e.g visible, or sub-visible particles contamination) as expressed in the United States Pharmacopeia (USP<790>, USP<788>) or European Pharmacopeia (E.P. 2.9.20, E.P. 2.9.19). Exogeneous and environmental particulates should be included in the CCS scope. It is acceptable to have a separate document dealing with product residue or cleaning agent contamination regulated by the EU Annex 15 and Chapter 3. This last document (cross-contamination program) can be part of the genealogy of the CCS documentation. 58% (56) of respondents have included product residue in their definition of particulate, while 19% (18) have only referred to particulate as exogenous (visible and sub-visible particulates) and environmental particulates. The rest did not yet define the term particulate.

59% have or plan to have a gap assessment of their current documentation (e.g., process map, risk assessment, procedure, and organizational measures) and practices against the CCS requirements. In comparison, 10% will not perform a gap assessment (Figure 6).

Ensuring that existing documentation and practices align with the CCS requirements and scope may help identify the critical controls. These critical controls must reflect the effectiveness of all the various controls (design, procedural, technical, and organizational) and monitoring measures employed to prevent the contamination risk. 62% of the respondents recognize the challenges in identifying all critical controls, while 11% do not think it will be a challenge. 18% of the respondents have already identified all their critical controls (Figure 7).

The CCS should consider all aspects of contamination control and its life cycle with ongoing and periodic review, resulting in appropriate quality system updates (1, 2). The periodic review is generally set at a defined period. However, some indicators or threshold values (e.g., Residual Risk Priority Number (RPN), quality performance indicator, Key performance indicator) suggesting an increase in the contamination risk or trend should trigger the review of the CCS to identify corrective actions (2) . 39% have not defined the threshold that would trigger the CCS review, while 25% have defined it (Figure 8). Some of the respondents have not (5%) or do not think (4%) it is required to determine a threshold value; they might consider that their Pharmaceutical Quality System will trigger the corrective action to manage risks associated with contamination.

The CCS calls for a holistic view of all the critical controls involved in managing risk associated with contamination (1,2,3). This holistic view should encompass an end-to-end supply chain that includes starting material (e.g., raw material, excipient) until the final product, the facilities, and the surrounding environment (e.g., facilities, equipment). We can quickly imagine how complicated this could be with complex supply chains involving multiple entities across the globe. However, despite this complexity, 55% of respondents plan to have a holistic and unique document to present their CCS, while only 9% will not (Figure 9).

There are various ways to implement a CCS. However, a thorough understanding of the manufacturing processes and surrounding environment is required to adequately define the CCS scope and the documentation structure that fits a pharmaceutical manufacturer’s process and its supply chain complexity (2) .

2. Case study of the implementation of the CCS by updating an existing Product Protection and Control Strategy (PPCS): 

Disclaimer for the case study : “the gap assessment summarized in table 2 represents documentation gaps between an overarching existing PPCS approach in line with the current GMPs and applicable guidances and a newly possible CCS aligned with the requirements of the Revision 12 draft of the EU GMP Annex 1”.

Implementing a CCS requires a cross-functional team of Subject Matter Experts (SME) who have a holistic understanding of the process, facility, and product contamination risks and regulations. The survey presented in the first section demonstrates that CCS development is a difficult exercise. It is more than just establishing a “sterility assurance quality manual.” It is about creating a strategy that includes holistic contamination risk management and ongoing evaluation of the improvement implemented to prevent contamination (1) .

3. Case Study

The case study presents the update of an existing strategy called “product protection and control strategy” (PPCS) , created several years ago, that:

• Includes microbiological and particulates contamination, product residue cross-contamination, chemical containment, and product degradation. During product technology transfer to a production site, a depth risk assessment is performed to identify all critical control points at the facility and process level, followed by documentation and implementation of the PPCS.
• Is already entirely integrated into the current Product Quality Management System and part of the Site Validation Master Plan. This step provides the strategic framework that assures that the manufacturing operates in a validated state and appropriate governance to enable balanced continuous improvements and investment plans.

Step 1: verify alignment with CCS scope and documentation structure expectations versus the existing PPCS

The scope of the CCS is clarified in the definition provided in the glossary of the EU GMP Annex 1 Feb 2020 revision draft v12. In addition, in point 2.1 and point 2.5, we have the following key expectations that identify the scope further: “minimize risks of microbial, particulate, and pyrogen contamination,” and “potential sources of contamination are attributable to microbial and cellular debris (e.g., pyrogen, endotoxins) as well as particulate matter (e.g., glass and other visible and sub-visible particulates).” In terms of the CCS document structure, the latest Annex 1 revision draft does not contain any special expectation.

Therefore, based on the proposed definition and elements in the Annex 1 revision draft, the following decision has been taken as summarized in Table 1.

In conclusion of step 1: the site decided to change the name of the PPCS to CCS to align with the expected terminology while keeping the PPCS structure.

Step 2: identify the gaps between the PPCS with the new CCS requirements while maintaining the PPCS structure.

The existing PPCS considers all the aspects of the contamination control from prevention by design, control per qualification and operations, to monitoring at critical control points, sterility assurance metrics performance evaluation, and continuous improvement. This process is in good alignment with the current drafted expectations at point 2.1, 2.2, and 2.3.

The current PPCS is based on six central pillars that include several key elements that need to be described in terms of contribution to the overall contamination risk management:

• Aseptic Gown design and cleaning/sterilization qualification, related supplier qualification
• Theoretical Training and Qualification of personnel which includes in the scope: hygiene, basics elements of microbiology (contamination sources and contamination prevention measures)
• Practical qualification to gowning in aseptic areas, to sterile manufacturing operations (general cleanroom practices, aseptic techniques, product process design, disinfection)
• Participation in Aseptic Process validation

B. Facilities, Equipment, Utilities & Infrastructures Design, Qualification, Maintenance, and Control Measures

• The design sub-elements are the facility layout, cleanroom design and classification, cross-contamination management where appropriate, and people and material flow
• Airborne Contamination Control measures HEPA filtration, airflow, and pressure cascades, localized unidirectional airflow protection, airflow Pattern qualification, continuous total particulates monitoring systems where appropriate
• Biocontamination control measures any associated equipment such as cleaning, disinfection, sterilization systems/processes, and related validations
• Cleanroom’s classification, qualification, and monitoring
• HVAC, pressure cascade, utilities, and production equipment systems alarms setting and qualification – Pest control programs
• Preventive and corrective maintenance programs
• Good housekeeping programs

C. Process Design, Validation, and Control Measures

• State of the art design: using closed systems, barrier technologies, single-use systems, highly automated and integrated systems facilitating data integrity expectations, cleaning and sterilization in place, online filter integrity testing, automated decontamination systems
• Cleaning and sterilization of all equipment and primary product components
• Product sterilization by filtration validation
• Clean, dirty, aseptic, and sterile hold times qualification
• Process Control Parameters qualification and Process validation
• Manufacturing and aseptic operation activities practices qualification and monitoring

D. Product and Container Closures Design, Validation, and Control Measures

• Critical Quality Attributes determination, qualification, control, and performance monitoring
• Raw materials, excipients, container closure systems, single-use systems used in production, selection and qualification, related suppliers’ qualification, and management
• Ready to Use or Ready to Sterilize Components when more appropriate
• Container Closure Integrity Validation
• Pre-filtration Bioburden, endotoxins and other In-process Control’s validation and implementation

E. Sterility Assurance Performance Metrics and Monitoring Program

• Cleanroom Environmental monitoring data, utilities monitoring data assessment and trending
• Facility and process alarms management and trending
• Product analytical controls management, assessment, and trending (in-process, release, and stability testing data) – Raw materials, excipients, and primary products containers control and monitoring data
• Product visual inspections data (defects classification, defects levels, trending)
• Process monitoring data
• Operators’ performance monitoring and trending (personnel monitoring and qualification data)
• Aseptic Process Simulations data
• Assets Qualification Monitoring data
• Housekeeping evaluation, fit ad finish program in classified areas
• Pest control data

F. Ongoing overall Quality Oversight and Continuous Improvement

• Deviation, complaints management
• Change Management
• Site self-inspection program, quality and sterility assurance field observation, global quality audits
• Supplier management and audit program
• Management review of the quality systems and process/product performance and quality metrics
• Regulatory inspections trends and observations
• Regulatory expectations and Technological evolutions survey

The decision was made to keep the six pillars structure, as they remain aligned with the current drafted Annex 1 expectations for the CCS documentation. Potential gaps or improvements needs were identified for each key element listed in each pillar with the latest draft EU GMP Annex 1 revision text. The potential gaps identified can be improvements in procedures, processes, or points/rationale that need further clarification.

This gap assessment was performed following these steps:

• Deep line per line, word by word analysis between the newly revised draft Annex 1 v12 and the current site strategy
• A search in the regulatory framework using the following keywords: CCS, Contamination Control, Contamination.
• A benchmark of practices through external workshop, training, or seminars (e.g., A3P, ISPE, ECA, PDA workshop/training on CCS) to identify if additional elements or best practices needed to be included.

Then the new elements based on the gap assessment have been included in a template table (table 2) to facilitate the update of the existing strategy.

Step 3: reference all key site strategies, rationales, reports, risk assessments, procedures, plans, etc., capturing the rationale for the site’s contamination control and sterility assurance risk management program.

As described at point 3.1 of the draft Annex 1: the Pharmaceutical Quality System “ PQS for sterile product manufacture should also ensure that: An effective risk management system is integrated into all areas of the product life cycle with the aim to minimize microbial contamination and to ensure the quality of the products manufactured. Risk management is applied in the development and maintenance of the CCS to identify, assess, reduce/eliminate (where applicable) and control contamination risks. Risk management should be documented and should include the rationale for decisions taken in relation to risk reduction and acceptance of residual risk. […] The risk management outcome should be reviewed regularly as part of ongoing quality management, during change control, and during the periodic product quality review. “

So far, all essential procedures were already referenced directly in the text of the documented current strategy. Still, based on the outlined new requirements, the decision was taken to collect and reference in addition the relevant key site strategies, supporting rationales, reports, risk assessments, plans, etc… to capture the justification underlining the site’s contamination control and sterility assurance risk management program. As for step 2, these new elements have to be included in the table 2 to facilitate the update section while re-using the pillars structure as presented previously.

Step 4: Update of the different sections of the CCS by the site’s Subject Matter Experts

Each site SME was involved in the gap assessment for its area of expertise and responsibilities. After the gap assessment was made, each SME had to:

• Update existing sections or create new sections to fill the gap between current procedures and regulatory/future requirements.
• Reference the adequate strategic documents, rationales, risk assessments, etc.

At the end of the four steps, the final CCS is a standalone comprehensive document with three major parts:

• The core text describes the CCS and the six pillars structure as described in step 2.
• The Table 2 records all relevant key CCS supporting strategies and assessments by the pillar as outlined in steps 3 and 4.
• A list of all Products/Production areas specific appendixes for chemical cross-contamination and product containment controls.

Step 5: Final holistic review by the CCS owner and approval by the senior management

As with any key strategic document (e.g., the site validation master plan), the CCS had to be approved by the senior management. The approvers formally commit to the described contamination risk management strategy and associated governance process to ensure product quality, patient safety, and continuous improvements by approving this CCS. It is clear that this CCS document will become a major expected deliverable of a sterile products manufacturing site during future regulatory inspections. This document includes a complete overview of contamination control management. It can directly be used as a support for the inspectors to verify the effective application of the described process and controls and to assess the robustness of the referenced supporting rationales and risks assessments.

It must be acknowledged that the creation (and even the update) of such a comprehensive document represents a challenge and necessitates an excellent transverse knowledge of the process and facility control elements. On the other hand, once finalized and approved, this CCS is also an excellent training tool for all employees who must be aware of their role in the holistic contamination control picture. One of the biggest challenges foreseen is defining an effective transversal performance dashboard and governance decision-making as suggested by the draft Annex 1 at point 2.4.

4. Conclusion

The CCS is a key strategic document/plan that describes the contamination risk management strategy and associated governance to decide the continuous improvements and investment plans to prevent contamination. Therefore, developing such a document requires a cross-functional team of experts with good production, QRM, and regulatory knowledge. This work will undoubtedly require extensive hours of meetings and teamwork.

Despite the second revision of the draft Annex 1 by Inspector Working Group (IWG) and several industry conferences and workshops around the CCS topic, need for additional practical guidance for establishing and documentation of an appropriate CCS is considered necessary by our industry.

It is logical to encounter different CCS understanding and implementation practices as suggested by the survey presented. This phenomenon may explain why the CCS scope may be different between manufacturers based on:

• the type of processes (e.g., downstream, upstream, medical device),
• type of product manufactured (sterile, non-sterile),
• manufacturer process knowledge and expertise,
• understanding of the draft Annex 1 version 12,
• the existing contamination control program in place.

Consequently, the implementation and the evaluation of the CCS will also differ between manufacturers. The practice difference is acceptable when the manufacturer can justify that the CCS will comply with regulatory requirements. This article shared one example of defining the CCS scope and implementing a CCS by updating an existing contamination control program.

However, it is up to the manufacturer to decide the scope and the elements (also called “points to consider” in draft Annex 1) being part of the CCS to create a strategy that includes a holistic contamination risk management and ongoing evaluation of the improvement implemented to prevent contamination.

The survey and the case study shed light on the industry challenges in:

• Agreeing on the CCS scope,
• Identifying all the critical controls,
• Organizing people roles and the PQS around the CCS, e.g., creating a new role, creating new governance bodies, or integrate it within the existing organization,
• Defining the threshold that would require review/evaluation of the CCS,
• Developing an effective transversal quality performance CCS dashboard.

This article is part of a series of articles. The second article will focus on the challenges of developing and implementing a CCS during the early design phase of a new project. The third article will present an example of an evaluation program to assess the performance of the CCS and how an efficient continuous improvement plan is identified.

Partager l’article

Isabelle Hoenen

[email protected]

Walid El Azab

[email protected]

[1] :  Second targeted stakeholders’ consultation on the draft revision 12 of Annex 1, on manufacturing of sterile medicinal products, of Eudralex volume 4 – Public Health – European Commission. https://ec.europa.eu/health/medicinal_products/consultations/2020_sterile_medicinal_products_en (accessed Jun 10, 2020)

[2] : Walid El Azab, Contamination Control Strategy: Implementation Roadmap, PDA Journal of Pharmaceutical Science and Technology, Volume 75, Number 5, September/October, 2021.

[3] : Johnson, L.; Hansy, C. Establishing a Contamination Control Strategy/Program: From Global Development to Site Implementation. https://www.americanpharmaceuticalreview.com/Featured-Articles/564173- Establishing-a-Contamination-Control-Strategy-Program-From-Global-Development-to-Site-Implementation/?catid=6262 (accessed Jun 10, 2020).

Case study: the crude MCHM chemical spill investigation and recovery in West Virginia USA

A. J. Whelton * a , L. McMillan b , C. L.-R. Novy b , K. D. White c and X. Huang a a Division of Environmental and Ecological Engineering and Lyles School of Civil Engineering, Purdue University, West Lafayette, IN, USA. E-mail: [email protected] b Environmental Toxicology Program, University of South Alabama, Mobile, AL, USA c Department of Civil Engineering, University of South Alabama, Mobile, AL, USA

First published on 21st March 2016

Several recent chemical spills have caused large-scale drinking water contamination incidents in Canada and the USA. The study goal was to identify key decisions and actions critical to incident investigations using the 2014 crude MCHM chemical spill in West Virginia USA as a case study. Environmental testing records, scientific reports, government documents, and communication records were reviewed. Results showed that thorough characterization of the spilled liquid and impacted source water is critical to assessing potential public health risks, estimating chemical fate, and designing infrastructure decontamination procedures that can restore infrastructure use. Premise plumbing water testing was not carried-out by responders but testing conducted by other organizations identified the decontamination procedures issued by responders and drinking water screening levels were not adequate to protect public health. Rapid bench-scale tests should be considered to (1) examine water treatment breakdown products, (2) evaluate chemical sorption and leaching by infrastructure materials ( i.e. , activated carbon, plastics), (3) predict water heater decontamination, and (4) estimate chemical volatilization during fixture use. Key actions to support an effective response and research needs were identified.

Introduction

Three incidents in early 2015 resulted in source water contamination and led to large-scale drinking water contamination in Nibley City, Utah (diesel fuel), Glendive, Montana (crude oil), and Longueuil, Quebec (diesel fuel). These reference cases revealed a wide array of investigative approaches applied by government agencies and utilities. In all cases, the contaminated source water was chlorinated prior to distribution, and contamination was first detected by customer complaints of petroleum odours at the tap. Upon the discovery that customers were receiving contaminated water, a water ban was established followed by flushing of water utility infrastructure. Customers were then directed to flush their premise plumbing.

Limited information regarding water testing activities during the Glendive and Longueuil incidents was available while no water testing information for the Nibley incident 2 was found. In Glendive, a variety of semi-volatile (SVOC) and volatile organic chemicals (VOC) were found in the source water and water distribution system ( Table 2 ). 4 Before premise plumbing flushing was authorized, airborne VOC testing was conducted indoors while faucets were running. 9,10 Unfortunately, this premise water was not chemically analysed. At least one resident reported becoming ill while following the flushing guidance issued by government agencies and the water utility. 11 In Longueil Canada, water quality and chemical analysis data for the water treatment plant and distribution system were available ( Table 3 ), but it is unclear if premise plumbing water testing was conducted. 7,12 In all incidents, no post-flushing premise water analysis seems to have been carried-out.

The observed inconsistency in reference case response actions indicates a deficiency in current investigation approaches. For example, it is unclear whether a thorough chemical analysis of the spilled liquid was completed, as data were not readily available. No data describing how water quality information was used to design subsequent water and indoor air sampling actions or actions to examine water treatment process generated by-products were found.

Furthermore, it is unclear if the sorption and desorption capabilities of water treatment media, plastic water distribution and premise plumbing components were considered in the response. No justifications for premise plumbing flushing protocol design, and estimates of indoor chemical volatilization during flushing were found. After an exhaustive literature review, no study that reviewed other drinking water contamination incidents to this detail was found. This lack of available data inhibits the identification of post-incident lessons learned for reference during acute, time-sensitive contamination events.

The study goal was to identify key decisions during a large-scale chemical drinking water contamination incident. Results were intended to assist the water, public health, and government sectors improve their decision-making judgments during incident response and recovery. This case study was also conducted to identify research needs.

The 2014 Elk River chemical spill in Charleston, West Virginia was used as a case study because a large number of organizations conducted independent water sampling and limited information was available to the responders:

1. The liquid that contaminated the source water was a chemical mixture,

2. More than 2 million people downstream relied on the affected source water as a water supply,

4. A water ban remained in effect for up to 10 days in some parts of the Charleston area.

Specific objectives of this study were to (1) review all available records pertaining to incident response and recovery actions created by private, public, and university organizations that participated, (2) use these results to outline key decisions, and (3) identify research needs for improving water contamination incident response and recovery.

Elk River incident overview and case study approach

Incident overview.

Federal health officials established short-term screening levels ( i.e. , concentrations considered safe for 14 days of ingestion) for three drinking water contaminants: 4-methycyclohexanemethanol (MCHM), polypropylene glycol phenyl ether (PPH), and dipropylene glycol phenyl ether (DiPPH). After the KVWTP and distribution system had undergone flushing, the order was lifted and the population was directed to flush the contaminated water out of their premise plumbing. Two and a half months after the spill, GAC filter media in the KVWTP that had been desorbing 4-MCHM from treated water was replaced. Several public, private, and non-profit organizations conducted bench- and field-scale testing. A detailed timeline of events for one year following the incident can be found in a supplemental data file published elsewhere. 19

Case study approach

Constituents in tank 396 liquid and their chemical properties.

RESP had difficulty identifying the numerous chemicals present in the water supply. After initial drinking water testing for 4-MCHM had occurred January 9 and the CDC established a health based screening level, 36 Freedom Industries, Inc. disclosed that an additional product called stripped PPH had also been present in the tank, 29 and thus had not yet been considered in health risk assessments. This disclosure did not come until 12 days after the spill. In response, RESP 37 investigated and found PPH and DiPPH in contaminated drinking water, and the CDC established screening levels for these compounds. 38 Eleven months after the spill, the U.S. Geological Survey (USGS) reported that methyl 4-methylcyclohexanecarboxylate (MMCHC), another ingredient in the tank liquid, was present in the water distribution system. 33 Although MMCHC was listed on the crude MCHM SDS, USGS was the only organization that tested for it. Customers were directed to flush their premise plumbing and it is unknown the degree airborne exposure occurred due to PPH, DiPPH, and MMCHC volatility.

Another complexity was that as the catalyst used to create crude MCHM aged, proportions of crude MCHM ingredients changed, 39 however, no compositional analysis data was available for how the levels of major and minor ingredients were affected. Furthermore, Freedom Industries indicated that once the crude MCHM product was obtained from Eastman Chemical Company this product was sometimes blended with stripped PPH, exposed to HCl to reduce pH, and water was removed. 40 These discoveries emphasize the risk government agencies and water suppliers face when relying on information generated and provided by parties connected to the spill. For example, SDSs did not contain any of this information. 28,30 Also evident is the risk encountered when toxicity information is not updated and/or not provided to users/regulators in their entirety and under context.

Because health officials did not understand which chemicals were present in the tank liquid and contaminated water when the spill occurred, they were unable to fully evaluate drinking water safety before issuing initial drinking water safety guidance. On January 9, the CDC issued a 28 day 4-MCHM screening level of 1 ppm. 36 But, 12 days after this CDC announcement, Freedom Industries' disclosed stripped PPH, another chemical mixture, was also in the tank liquid. This disclosure prompted the CDC to reactively establish 14 day health based screening levels for PPH (1.2 ppm) and DiPPH (1.2 ppm). 37 On January 13 WVAW eliminated the do not use order for some parts of their distribution system. The USGS initiated their own tap water study of their Charleston, West Virginia office building nine days after the spill and detected MMCHC in the drinking water distribution system. 33 While the CDC and State of West Virginia health risk assessments considered pure MCHM and crude MCHM, for which MMCHC is a constituent, pure MMCHC was not the subject of independent risk assessments. The presence and toxicity of breakdown products created as contaminated water travelled through the KVWTP and the water distribution system were not considered in these assessments. Limited tank liquid and water sampling data have resulted in an incomplete understanding about the presence of other chemicals in the water supply.

Two months after the spill, toxicologists working with the West Virginia Testing Assessment Project (WVTAP) reviewed available toxicology data for the ingredients listed on SDSs. 47 WVTAP toxicologists established lower screening levels than the CDC for 4-MCHM (0.120 ppm vs. 1 ppm), PPH (0.850 ppm vs. 1.2 ppm), and DiPPH (0.250 ppm vs. 1.2 ppm). 48 These lower screening levels were due to differences in risk assessment methodologies and assumptions: exposure pathways (WVTAP considered ingestion, inhalation, and dermal exposure not just ingestion), a longer exposure period (28 days not 14 days), and a more inclusive sensitive population (formula-fed infant not 10 kg child). 20 It is the first-hand experience of author Dr. Whelton that WVTAP did not consider a screening level for MMCHC because WVTAP was unaware that this chemical was present in the drinking water when their investigation took place. The 0.010 ppm 4-MCHM screening level established by the State of West Virginia was lower than both the CDC 1 ppm and WVTAP 0.120 ppm screening level. The State of West Virginia accepted the CDC screening levels for PPH and DiPPH.

Exposure to the contaminated water however occurred for 2.5 months, past the 14 day CDC screening levels and 30 day WVTAP screening levels. GAC filters in the KVWTP were found to be contaminated with 4-MCHM and were not replaced until 2.5 months after the incident. 49 While the CDC issued screening levels as a short-term urgent evaluation based on limited information, these levels were not revised to account for the longer exposure duration that occurred.

A variety of academic and government organizations are conducting toxicological research studies and two studies have been completed as of March 2016. One study found pure 4-MCHM exhibited toxicity to yeast and human lung cells including DNA damage. 50 To date, the authors do not know of any studies that have been conducted to identify short- and long-term health impacts of inhalation exposures experienced due to this incident. Since the spill, several conference presentations have also been made regarding chemical toxicity. One study reported that a compound similar to PPH caused “impacted developmental physiology in embryonic zebrafish and negatively affected developing motor, behavioural, and social systems.” 51 Another study indicated additive toxicity was detected in vitro when several different cell lines were exposed to 4-MCHM and PPH. 52 Also reported was that crude MCHM exposure induced toxicity for Danio rerio . 53 The authors are aware that additional studies are underway and will be made available by academic institutions in the coming years. Results from follow-up human health impact studies on the tank liquid were not found.

While several organizations have acknowledged the inhalation exposure pathway existed, 13,45,54,55 no tests have been conducted to investigate the short- and long-term health effects due to that contaminated water exposure pathway. Shortly after January 9, the CDC chose not to consider inhalation toxicity in their screening levels “due to the lack of toxicological information on inhalation, lack of an effective model for inhalation, and lack of a method to analyse the actual amount of MCHM in the air”. 45 Although months later the EPA 55 established a 4-MCHM inhalation screening level. The US National Toxicology Program 56 initiated testing to examine health effects caused by the ingestion and dermal exposure to contaminated water. However, both organizations have acknowledged these ongoing studies do not address the inhalation exposure pathway. There is a 20 year precedent that volatile contaminants can express different toxicity by the inhalation exposure pathway compared to the ingestion of contaminated water. 57 “Inhalation is recognized as being the easiest and fastest means of exposure because vapours are readily accessible to the respiratory tract.” 58 To date, the authors are not aware of any studies conducted to identify the short- or long-term health impacts of inhalation exposures experienced due to this incident. This is surprising because building inhabitants were told to flush their premise plumbing with hot water and incidents of illness indicative of inhalation exposures were detected in the population by multiple local, county, state, and federal agencies. 19,59

Source water sampling

Three weeks after the spill was detected contractors working for Freedom Industries, Inc. began chemically analysing spill site storm water, ground water, and soil samples. The contractors found significant surface and subsurface chemical contamination up to 20 feet below ground surface ( Table 6 ). 61,62 Subsurface characterizations revealed that contaminated groundwater flowing toward the Elk River. EPA 35 also tested spill site water samples and found 4-MCHM, PPH, and variety of TICs ( Table 5 ). Neither contractors nor the EPA analysed environmental samples for DiPPH despite this compound having been detected in the contaminated drinking water and having a CDC established screening level. There was no central data repository for all environmental monitoring and sampling data so it was difficult to understand site conditions. Results show that different government and private organizations characterized environmental media for different chemicals and no justification for these dissimilar approaches was found.

In the months following the spill, some environmental fate studies were completed. In downstream rivers the USGS detected the crude MCHM ingredient MMCHC. 33 Bench-scale studies indicated that 4-MCHM isomers were susceptible to aerobic and anaerobic degradation. 68–70 However, knowledge-gaps remain. From January 13–18 grab samples were analysed by the Charleston Sanitary Board for 4-MCHM in their wastewater treatment plant influent and effluent. A total of 13 samples were collected and no 4-MCHM was detected above the 6 ppb 4-MCHM method detection limit. This was the only wastewater monitoring data found by the authors during this study. However, other wastewater facilities and collection systems ( i.e. , Elk Valley) received 4-MCHM contaminated wastewater from communities that flushed their premise plumbing (and this WWTP discharged effluent upstream of the KVWTP intake). The fate of 4-MCHM and other tank liquid ingredients in the wastewater infrastructure remains poorly understood. Another challenge is that biodegradation studies did not use the tank liquid (a mixture of stripped PPH and crude MCHM), but instead examined crude MCHM. It remains unknown if the liquid spilled into the river exhibited the same degree of biodegradation. No river water or wastewater testing was conducted for PPH, DiPPH, or any other tank liquid ingredient. Tank liquid dispersion and advection in the water column, chemical partitioning between the water and sediment, and the magnitude of volatilization that took place remain unreported, and thus unclear. While 4-MCHM river water monitoring was rapidly conducted by a variety of organizations, absence of thorough river water characterization has resulted in an incomplete understanding of what other chemicals were present and their fate. It is also unknown if MMCHC or other tank liquid ingredients were distributed to the City of Huntington population in treated drinking water due to lack of publicly available data.

Water treatment and distribution system monitoring

USGS analysed drinking water collected from their own Charleston office building after their building was flushed. 33 The USGS found 4-MCHM concentrations similar to those observed by RESP. Unlike RESP however, the USGS screened for contaminants other than 4-MCHM and detected MMCHC, 33 but did not quantify its concentration.

Monitoring at premises

There remains an incomplete understanding of what chemicals and concentrations existed in premise plumbing because: (1) RESP chose to flush premises for 15 minutes before collecting a water sample, (2) water sampling did not begin until contaminated water had been distributed to the population, (3) water distribution system sampling data imply that the most contaminated water may have passed through the KVWTP before water distribution system sampling was initiated, (4) while a do not use order was in effect, the population was permitted to use contaminated water for toilet flushing activities thereby allowing contaminated water to pass through premise plumbing without characterization, (5) chemical analyses of premise water was not exhaustive and thus the presence and concentration of other compounds ( i.e. , PPH, DiPPH, MMCHC) was not determined. As a result, while the existing premise water testing data are informative, a poor understanding of the chemical composition and composition of contaminated premise water remains.

During the incident response, the public became concerned that chemicals present in their water might sorb into and out of plastic pipes found in premise plumbing thereby continually contaminating their drinking water over time. 78 The EPA publicly disputed this claim 78 and cited unpublished, restricted access documents. 78

Premise water testing conducted before and after flushing revealed that premise flushing procedures did not reduce 4-MCHM concentrations in some homes while 4-MCHM concentrations were greater after flushing in others. 19,70 A water heater modelling study completed after the spill indicated some of the flushing procedures were not capable of reducing 4-MCHM below the CDC's 1 ppm screening level when homes contained large water heaters, low-flow fixtures, and when 4-MCHM was present in water used to flush water heaters. 1 An analysis of premise plumbing decontamination procedures issued in response to past water contamination incidents in the U.S. revealed similar deficiencies. 1

During the incident persons who presented to emergency departments seeking medical care reported being exposed to drinking water by “breathing a mist of vapour.” 86 Nine months after the incident EPA established a 0.01 ppm-v inhalation 4-MCHM screening level based on the CDC's 1 ppm ingestion based screening level. EPA's methodology has been explained elsewhere. 55 Ambient air testing was conducted by EPA 10 months after the spill 2014 at the Freedom Industries spill site during site remediation activities. Air testing revealed 4-MCHM was present in air up to 0.142 ppb-v concentration. 88 More than a year after the spill, results from two indoor air modelling studies were released and predicted that (1) when residents flushed their premise plumbing to include showers, dishwashers, and faucets, the EPA 4-MCHM air screening level was exceeded 89 and (2) 4-MCHM could volatilize into the air during showering. 43 No studies were found that reproduced volatilization conditions in premises to confirm these predictions. In 2015 the spill site remediation contractor required respiratory protection for its workers citing that potential airborne 4-MCHM levels could exceed 0.01 ppm-v. 90 Despite inhalation exposure evidence and lacking inhalation toxicity data some state and federal organizations have not made clear that their toxicological evaluations conducted since the spill do not apply to the inhalation exposure pathway. 91,92

Premise 4-MCHM concentrations decreased in the weeks following the do not use order ( Fig. 1 ). One month after the spill, WVTAP conducted the last known in-home water testing effort in 11 residences and detected a maximum concentration of 6.1 ppb 4-MCHM. PPH concentrations in 11 homes were also measured by WVTAP one month after the spill and were not detected (0.5 ppb MDL). 20 Based on records reviewed, no other organization characterized premise water for PPH during the response. No record was found for any organization that characterized premise water for DiPPH.

Two aldehydes were detected during premise water sampling and their source remains unclear. Formaldehyde was present in the spilled liquid and was detected in premise drinking water four days and one month after the spill. 32,94,95 ATTY found formaldehyde in an affected restaurant's toilet during the water ban at 32 to 33 ppb. This result was presented by a scientist working for ATTY to a West Virginia legislative committee and received global press. 94–96 The scientist speculated that formaldehyde was a breakdown product of the spilled liquid and residents were being exposed to this carcinogen. 84 The National Toxicology Program previously named formaldehyde as a carcinogen. 97 No studies were found that addressed the claim that 4-MCHM “broke down in showers or the water system.” WVTAP found formaldehyde and acetaldehyde in premise drinking water one month after the spill (5.6 to 11 ppb, 2.7 to 2.8 ppb, respectively). 32 The literature indicates that both aldehydes could have formed as a consequence of water treatment processes 98 present at the KVWTP and have been found in drinking water in other cities up to 20 ppb and 12 ppb, respectively. 98–101 Formaldehyde and acetaldehyde were present well below World Health Organization health standards (50 ppb formaldehyde, 8 ppb acetaldehyde) and standards for drinking water odour (800 ppb formaldehyde; 4 ppb acetaldehyde). 102,103

Some TICs were detected in premise water by several organizations ( Table 5 ). Work by WVTAP revealed that some TICs detected by chemical analysis of laboratory processed premise water samples were the result of interactions between chlorine disinfectant residual and stabilizers used in the laboratory's liquid–liquid extraction solvent. 20,104 This result underscored the importance of understanding how TICs are formed and exposed a deficiency in that no standardized water sampling and processing method was applied during the incident response. 3-Chlorocylcohexene, was the only TIC found with an estimated concentration, 193 to 928 ppb. This contaminant was reported in drinking water obtained from flushed residences 18 days after the spill. 77

Very few researchers analysed drinking water for metal contaminants. Many metals were detected in premise drinking water and some exceeded health (Cu, Pb) and aesthetic based drinking water standards (Al, Fe, Mn) before premise flushing. 19 After flushing, no metals were found to exceed drinking water standards in the very small number of residences sampled. Blue coloured solids were also collected in homes during flushing and were analysed by X-ray photoelectron spectroscopy. 19 While the State of West Virginia reported that the solids exiting the faucet during flushing were sediment, 105 chemical analysis revealed some material was not sediment. Blue coloured solids that were collected contained less than 1% silica, as well as oxygen (58%), aluminium (18%), carbon (17%), zinc (1.4%), phosphorus (1.4%), fluorine (1.0%), chromium (as Cr +6 ) (0.8%), calcium (0.2%), and copper (0.1%).

Odour analysis of premise water, combined with analytical results for 4-MCHM, enabled the discovery that (1) the tank liquid had a different characteristic odour than pure 4-MCHM, a standard some researchers studied for sensory analysis, and (2) black liquorice odour was present when 4-MCHM was not detected at or above 10 ppb, the MDL at the time of the early response. Premise drinking water was also analysed for other characteristics such as total organic carbon and ultraviolet absorbance, but these water quality characteristics were not found to indicate contaminated water. 19 This is because drinking water contaminant concentrations were too low and did not have aromatic characteristics detectable by UV absorbance measurement or organic carbon concentrations greater than typical drinking water values.

Chemical identification and properties

Many of the problems associated with this incident are a consequence of RESP not fully understanding what chemicals were present in the contaminated drinking water. RESP 108,109 trusted Freedom Industries, Inc. to fully disclose the chemical products that were in the tank liquid which they did not. No SDS 28,30 explained that the tank liquid that spilled into the Elk River had been previously treated with hydrochloric acid or dewatered after stripped PPH had been mixed into crude MCHM. 40 RESP did not know where to find physiochemical property data for many of the suspected tank liquid ingredients, and the RESP and CDC solely focused on the potential health impacts of 4-MCHM exposure despite a variety of other chemicals being present in the affected waters. As a result of these actions, health officials were unable to establish acceptable drinking water exposure limits for all of the chemicals present in the contaminated water. It is the author's conclusion that RESP and CDC underestimated the health risk posed to customers as well as the fate of the chemicals in the utility's water infrastructure and customer's premise plumbing. For example, the tank liquid chemicals that were present in the drinking water were not all identified 33 before their initial risk assessments were created 36 and flushing was recommended, nor was their fate in plumbing or indoor air understood. 19,20,43,70,74,89

Results of this case study show that once a spill occurs, the spilled liquid should be chemically characterized to ascertain its composition. The findings underscore the need for responders to also acknowledge toxicity information available on SDSs may not be accurate. For this reason, it is important responders obtain samples of the spilled product and rapidly investigate its composition and toxicity.

In future incidents, government agencies and water utilities should not only rely on the parties who either caused or were involved in the spill to fully disclose the liquid composition, but initiate their own rapid characterizations. Multiple laboratories should analyse the liquid, as this increases the probability of detecting compounds some laboratories miss and ensures quality assurance and quality control methods. As WVTAP discovered in the response, at least one laboratory conducting 4-MCHM analysis for the State could not detect low levels of 4-MCHM in water that they claimed to be able detect. 91 Failure to understand the chemicals present in the water amplified the consequences of RESP decisions. For example, premise plumbing flushing occurred without full knowledge of what chemicals customers would be exposed to in their homes or if flushing hot water would result in greater exposures. Disclosure that the USGS detected MMCHC in the water distribution system two to four weeks after the spill underscores the need to thoroughly characterize the contaminated drinking water. Officials cannot make scientifically sound judgments if they are unaware of which chemicals are in contaminated drinking water.

Tentative identified compound (TIC) reporting

TIC identification is a standard practice when “there is reasonable probability of contamination with unconventional pollutants,” and helps to gauge other compounds that might otherwise be missed in the water. 110,111 The value of TIC reporting was evidenced by the USGS's TIC discovery that MMCHC was present in drinking and Elk River water samples. Because of MMCHC's tentative identification, USGS followed-up and confirmed its presence with an analytical standard. 33 TIC reporting should be considered in future water contamination incident responses as a screening method. A challenge that occurred in West Virginia was that analytical standards did not readily exist for all TICs. In such scenarios, science grounded strategies must be developed to make certain the public is best protected from the contaminated water containing these possible contaminants.

Rapid bench-scale experiments

Infrastructure, water quality, and flushing, considerations for premise water sampling and flushing.

On certain days, higher 4-MCHM concentrations were found in premises than in the water distribution system. This difference may have been caused by the lag in residents flushing water from their premise plumbing and/or because water distribution system sampling data were not representative of 4-MCHM concentrations the entire population encountered. The variety of water characterization techniques (organics, inorganics, and odour) had varying usefulness.

Premise plumbing decontamination and exposure

Building inhabitant exposure to airborne contaminants that volatilized from the water during flushing and routine water use was not considered in the WVAW flushing guidance, the most widely circulated guidance. 79 The black-liquorice odour of the contaminated drinking water (at room temperature) indicated chemicals could volatilize and inhalation was a viable chemical exposure pathway. Spikes in patient admittances at physician offices and hospital emergency rooms seem to support this exposure pathway. The CDC dropped plans to consider inhalation as a viable exposure pathway during their initial 4-MCHM screening level development and cited: “lack of toxicological information and the lack of an effective model to estimate inhalation”. 45 Nine months later, the EPA established an inhalation screening level for 4-MCHM. To accurately protect the population it is critical to understand all exposure pathways including dermal and inhalation rather than assuming ingestion alone and establish premise flushing procedures that minimize the risk to human health.

A review of past drinking water chemical contamination incidents revealed that premise flushing procedures issued in the U.S. have not been based on plumbing system design, operations, or materials. A recent study 1 and another underway define several premise plumbing decontamination considerations. 112 At present, water heater cleaning scenarios can be evaluated using a water heater flushing model 1 available as an MS Excel spreadsheet. A model for predicting chemical emission into indoor air during flushing from dishwashers, washing machines, faucets, showers has been developed 89 and will be refined. Government agencies and utilities should consider these easy to use models when determining how to flush premise plumbing. Additional work should be conducted to improve these models and better predict chemical levels in indoor air. Organizations should also consider recommendations for personal protective equipment and practices building occupants should implement to protect themselves from exposure.

Key incident response and recovery actions

It is also important to recognize that results of the present study differ significantly from EPA efforts and their Response Protocol Toolbox (RPTB). 113 The RPTB effort was initiated shortly after September 11, 2001 in an effort to better understand how to respond to drinking water contamination incidents. First, the RPTB contains a stepwise process for incident investigation, which primarily involves “assessing the threat, determining if it is credible, and confirming that an incident has occurred”. When chemical spills occur and the water supply is known to be contaminated, the EPA's RPTB approach does not seem applicable. Furthermore, cleaning out affected water infrastructure and premise plumbing and protecting the population during the process is critical for the community to recover from the incident. The RTPB guidance does not address these actions.

Eight years ago the U.S. water sector outlined several needed water contamination research activities, some in partnership with the EPA, but very few have been addressed. 114 To obtain the necessary data and in light of the fact that large-scale drinking water contamination incidents continue to occur, the authors propose the U.S. water sector instead seek alternative research mechanisms and partners. In retrospect, many of the discoveries from the Elk River chemical spill could have been addressed many years ago.

A variety of activities should be considered to improve the water and public health sector's ability to investigate and respond to water contamination incidents.

• Develop an approach for rapid analytical characterization of complex liquids ( i.e. , coal washing liquid, oils, etc. ) and matrices ( i.e. , river water, drinking water, wastewater).

• Develop methods to rapidly predict chemical fate in water treatment, water distribution systems, and premise plumbing.

• Further develop premise plumbing hydraulic and indoor air exposure assessment models, and develop a better understanding of chemical–material interactions.

• Establish mechanisms whereby persons/organizations not formally involved in the response can access samples available to responders and provide data to responders.

• Make data collected by responders centrally and publicly available during the incident response and recovery.

• Train and conduct disaster response water contamination exercises 115 using realistic scenarios including conditions described in this case study.

Using this case study, the water and public health sectors can improve their ability to rapidly respond to and recover from incidents. The long-term health effects caused by drinking water contamination may continue until pertinent research is conducted. Despite this clear problem, if the water and public health sectors implement some of the recommendations identified in this study the chances that a population will be exposed to contaminated water could be diminished or avoided altogether. Results of this study can help expedite government agency and water utility decision making processes.

Conclusions

As demonstrated by organizations that responded to the chemical spill, no widely accepted approach to rapidly identify and quantify chemicals present in contaminated drinking water was applied. As a result, health officials did not fully understand which chemicals residents were being exposed to in their drinking water for months following the January 9 spill's discovery. Future work is needed to determine adequate methods for rapidly collecting and characterizing spilled liquids, raw, and treated waters. This will not be trivial and could include a national expert workgroup.

The Elk River chemical spill response and recovery also underscored the need for rapid and standard tests that can identify breakdown and transformation products as contaminated water passes through water treatment plants. Also needed are methods to predict if contaminants are preferentially sequestered as water passes through water treatment processes ( i.e. , oxidation, activated carbon) and infrastructure ( i.e. , pipe/coatings).

The incident revealed that the actions needed to safely decontaminate premise plumbing are poorly understood. A stepwise decontamination process has been described elsewhere 1 but additional work is needed to address knowledge-gaps. It is recommended that flushing and other infrastructure decontamination protocols be thoroughly tested and air monitoring should be conducted in conjunction with water sampling before the public is told to flush their premise plumbing. If responders do not fully understand the contaminants present in the contaminated water, health officials cannot issue guidance to best protect the population from harm. If chemical testing is not thoroughly conducted during the early stages of the incident, this lack of data will affect all downstream public health decisions possibly extending the recovery period, resulting in lost public confidence, spread of contamination, and causing the population to experience adverse health impacts.

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Case studies in groundwater contaminant fate and transport

A case study of groundwater contamination is a detailed study of a single site contaminated with a chemical or mixture that is known to be a problem at many sites. The goal of case studies is to provide insights into the physical, chemical, and biological processes controlling migration, natural attenuation, or remediation of common groundwater contaminants. Ideally, processes occurring at a case study site are representative of other sites so that knowledge gained from these intensive studies can be applied at thousands of sites where fewer data are available. Several characteristics of case studies contribute to their value. First, they may have tens to hundreds of monitoring wells, compared to fewer than ten wells at some contaminated sites. Second, some case studies continue for many years or even decades, providing insights into temporal progression of slow processes. Third, analytical methods prohibitively expensive for routine use or under development may be tested at case study sites. Finally, the ongoing characterization typical of case study sites builds a foundation of knowledge that facilitates sophisticated experimental design and testing of new methods. This article is divided into sections based on the contaminant type because the chemical and biological processes required for remediation vary for each contaminant. Most importantly, some contaminants can be biodegraded whereas metals and radionuclides cannot be destroyed but can be immobilized or rendered less toxic. The emphasis is on case studies of natural processes that control the fate and transport of contaminants in groundwater rather than on active remediation methods. The principles learned from these studies may form the basis for design of remedial strategies. The organic contaminants are divided into: petroleum hydrocarbons, fuel oxygenates, coal tar and wastes from manufactured gas plants, and chlorinated solvents. The inorganic contaminants covered are metals and radionuclides, arsenic, and nitrate. Case studies of mixed waste plumes from landfills are also described. Experimental sites where contaminants have been introduced into an aquifer as an emplaced source or a controlled release may not meet the above definition of case studies, but some are included because the overall goal is to impart lessons learned from detailed field studies. It is impossible to cover all case studies in this short format. Conversely, focusing on one or two does not convey the breadth of research results in entire range of case studies. Instead, the strategy is to describe the evolution of knowledge for each contaminant class while providing citations of relevant case studies. Much of the progress in understanding of the fate of contaminants in groundwater is based on laboratory studies; thus whenever possible, papers that included both field and laboratory results have been included among the citations. Two topics of growing importance have not been covered. These are the fate of pharmaceuticals in groundwater and discharge of contaminant plumes to surface water. These topics merit coverage in the future as knowledge grows and case studies increase in number.

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Related content, barbara a. bekins, phd, research hydrologist.

Flint Water Crisis: Everything You Need to Know

After officials repeatedly dismissed claims that Flint’s water was making people sick, residents took action. Here’s how the lead contamination crisis unfolded—and what we can learn from it.

Fearful of using the tap water to wash their food, Flint residents Melissa and Adam Mays prepare meals with bottled water.

Brittany Greeson

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A story of environmental injustice and bad decision making, the water crisis in Flint, Michigan, began in 2014, when the city switched its drinking water supply from Detroit’s system to the Flint River in a cost-saving move. Inadequate treatment and testing of the water resulted in a series of major water quality and health issues for Flint residents—issues that were chronically ignored, overlooked, and discounted by government officials even as complaints mounted that the foul-smelling, discolored, and off-tasting water piped into Flint homes for 18 months was causing skin rashes, hair loss, and itchy skin. The Michigan Civil Rights Commission, a state-established body, concluded that the poor governmental response to the Flint crisis was a “result of systemic racism.”

Later studies would reveal that the contaminated water was also contributing to a doubling—and in some cases, tripling—of the incidence of elevated blood lead levels in the city’s children , imperiling the health of its youngest generation. It was ultimately the determined, relentless efforts of the Flint community —with the support of doctors, scientists, journalists, and citizen activists—that shined a light on the city’s severe mismanagement of its drinking water and forced a reckoning over how such a scandal could have been allowed to happen.

Flint Water Crisis Summary

Flint water crisis update, why is lead-contaminated water bad, beyond flint.

Long before the recent crisis garnered national headlines, the city of Flint was eminently familiar with water woes. For more than a century, the Flint River, which flows through the heart of town, has served as an unofficial waste disposal site for treated and untreated refuse from the many local industries that have sprouted along its shores, from carriage and car factories to meatpacking plants and lumber and paper mills. The waterway has also received raw sewage from the city’s waste treatment plant, agricultural and urban runoff, and toxics from leaching landfills. Not surprisingly, the Flint River is rumored to have caught fire—twice.

As the industries along the river’s shores evolved, so too did the city’s economy. In the mid-20th century, Flint—the birthplace of General Motors—was the flourishing home to nearly 200,000 people, many employed by the booming automobile industry. But the 1980s put the brakes on that period of prosperity, as rising oil prices and auto imports resulted in shuttered auto plants and laid-off workers, many of whom eventually relocated. The city found itself in a precipitous decline: Flint’s population has since plummeted to just 100,000 people, a majority of whom are Black, and about 45 percent of its residents live below the poverty line. Nearly one in six of the city’s homes has been abandoned.

This was the lay of the land in 2011, when Flint, cash-strapped and shouldering a $25 million deficit, fell under state control. Michigan Governor Rick Snyder appointed an emergency manager (basically an unelected official chosen to set local policy) to oversee and cut city costs. This precipitated the tragic decision in 2013 to end the city’s five-decade practice of piping treated water for its residents from Detroit in favor of a cheaper alternative: temporarily pumping water from the Flint River until a new water pipeline from Lake Huron was built. Although the river water was highly corrosive, Flint officials failed to treat it, and lead leached out from aging pipes into thousands of homes.

Five-month-old Dakota Erler of Flint gets blood drawn from her heel in order to have her lead levels tested at Carriage Town Ministries in 2016.

Lead levels in Flint water

Soon after the city began supplying residents with Flint River water in April 2014, residents started complaining that the water from their taps looked, smelled, and tasted foul. Despite protests by residents lugging jugs of discolored water, officials maintained that the water was safe. A study conducted the following year by researchers at Virginia Tech revealed the problem: Water samples collected from 252 homes through a resident-organized effort indicated citywide lead levels had spiked, with nearly 17 percent of samples registering above the federal “action level” of 15 parts per billion (ppb), the level at which corrective action must be taken. More than 40 percent measured above 5 ppb of lead, which the researchers considered an indication of a “very serious” problem.

Even more alarming were findings reported in September 2015 by Flint pediatrician Mona Hanna-Attisha: The incidence of elevated blood-lead levels in children citywide had nearly doubled since 2014—and nearly tripled in certain neighborhoods. As Hanna-Attisha noted, “Lead is one of the most damning things you can do to a child in their entire life-course trajectory.” In Flint, nearly 9,000 children were supplied lead-contaminated water for 18 months.

More problems with Flint water

Flint’s water supply was plagued by more than lead. The city’s switch from Detroit water to the Flint River coincided with an outbreak of Legionnaires’ disease (a severe form of pneumonia) that killed 12 and sickened at least 87 people between June 2014 and October 2015. The third-largest outbreak of Legionnaires’ disease recorded in U.S. history—as well as the discovery in 2014 of fecal coliform bacteria in city water—was likely a result of the city’s failure to maintain sufficient chlorine in its water mains to disinfect the water. Ironically, the city’s corrective measure—adding more chlorine without addressing other underlying issues—created a new problem : elevated levels of total trihalomethanes (TTHM), cancer-causing chemicals that are by-products of the chlorination of water.

Flint residents go to court

One of the few bright spots of the Flint water crisis was the response of everyday citizens who, faced with the failure of city, state, and federal agencies to protect them, united to force the government to do its job. On the heels of the release of test results in the fall of 2015 showing elevated lead levels in Flint’s water—and its children— local residents joined with NRDC and other groups to petition the U.S. Environmental Protection Agency (EPA) to launch an immediate emergency federal response to the disaster. The EPA failed to act, which only spurred residents on.

In early 2016, a coalition of citizens and groups—including Flint resident Melissa Mays, the local group Concerned Pastors for Social Action, NRDC, and the ACLU of Michigan— sued the city and state officials in order to secure safe drinking water for Flint residents. Among the demands of the suit: the proper testing and treatment of water for lead and the replacement of all the city’s lead pipes. In March 2016, the coalition took additional action to address an urgent need, filing a motion to ensure that all residents—including children, the elderly, and others unable to reach the city’s free water distribution centers—would have access to safe drinking water through a bottled water delivery service or a robust filter installation and maintenance program.

Those efforts paid off. In November 2016, a federal judge sided with Flint residents and ordered the implementation of door-to-door delivery of bottled water to every home without a properly installed and maintained faucet filter. A more momentous win came the following March with a major settlement requiring the city to replace the city’s thousands of lead pipes with funding from the state, and guaranteeing further funding for comprehensive tap water testing, a faucet filter installation and education program, free bottled water through the following summer, and continued health programs to help residents deal with the residual effects of Flint’s tainted water.

But the work of Flint residents and their advocates isn’t finished yet. Ensuring that the provisions of the 2017 settlement are met is an ongoing task. Indeed, members of the lawsuit have already returned to court to see that the city properly manages its lead service line replacement program and provides filters for faucets.

Melissa Mays and other Flint residents address the media after the House Oversight and Government Reform Committee hearing to examine the Flint water situation in 2016.

Molly Riley/Associated Press

Does Flint have safe water yet?

Governor Snyder seemed to signal the all-clear in April 2018 when he announced that the city would stop providing bottled water to residents. Indeed, there is some evidence that the situation in Flint is improving, with lead levels remaining below the federal action level for the past four six-month monitoring periods, from July 2016 to June 2018.

However, it is important to note that thousands of Flint residents are still getting their water from lead pipes. The federal action level for lead is not a health-based number; it merely is an administrative trigger for remediation by the water utility. The EPA and other health authorities agree that there is no safe level of lead in water, so the continuing use of lead pipes by thousands of Flint residents remains a concern, particularly in light of their cumulative lead exposure over many years.

The FAST Start program implemented by the city in March 2016 is working to replace the thousands of lead and galvanized steel service lines that connect Flint water mains to city homes by 2020. But as of October 2018, only a little more than 7,500 pipes had been upgraded. The slow pace of progress drew the group of residents working with NRDC back to court to demand that Flint comply with its obligations to identify and replace lead pipes and supply filters to residents after each pipe replacement.

Flint water crisis charges

In early 2016, Michigan Attorney General Bill Schuette announced an independent review to “determine what, if any, Michigan laws were violated” during Flint’s drinking water disaster. Over the course of his investigation, 15 people have been charged as criminally responsible for causing or contributing to the crisis.

To date, the most senior official to be charged is Nick Lyon, director of Michigan’s Department of Health and Human Services (MDHHS), who is standing trial for involuntary manslaughter in the deaths of two men linked to the Legionnaires’ disease outbreak. While awaiting trial, Lyon remains the state’s health director.

Among other officials charged are the state’s chief medical executive, Dr. Eden Wells, who allegedly threatened to withhold funds for a project after researchers began looking into the Legionnaires’ outbreak, and four state officials charged with tampering with lead test results and instructing residents to flush their taps ahead of testing (which can produce artificially low lead-level results). Two former Flint emergency managers, three Flint city officials, and a handful of Michigan Department of Environmental Quality (MDEQ) and MDHHS employees have also been charged. Meanwhile, Governor Snyder has not been charged with any crime.

Resident Lorenzo Lee Avery Jr. stands outside of Flint City Hall during a Flint Lives Matter event in 2016. The city’s ongoing water crisis has left residents dependent on bottled water.

Easy to melt and malleable, lead is a heavy metal that has been used by people for millennia. The Romans added it to makeup, cookware, and paint and even consumed it as a sweet seasoning and preservative in wine. They used lead in the pipes for their famous baths as well as their aqueducts. Not surprisingly, the word plumbing is a derivative of plumbum , the Latin word for lead.

Yet then as now, lead exposure was linked to serious health impacts—even madness and death. Modern science shows that even low levels of lead can impair the brain development of fetuses, infants, and young children. The damage can reverberate for a lifetime, reducing IQ and physical growth and contributing to anemia, hearing impairment, cardiovascular disease, and behavioral problems. Large doses of lead exposure in adults has been linked to high blood pressure, heart and kidney disease, and reduced fertility.

Pure lead pipes, solder, and fittings were banned from U.S. water systems in 1986 (it was only in 2014 that allowable lead levels in plumbing and fixtures dropped to 0.25 percent), and national regulations for lead testing and treatment of public water supplies were established in 1991 with the Lead and Copper Rule. While action by the water utility is required once the level of lead in public water supplies reaches 15 ppb (as measured at the 90th percentile of samples collected), the EPA acknowledges that “there is no safe level of exposure to lead.” Independent tests conducted in fall 2015 revealed that nearly 17 percent of samples from hundreds of Flint homes measured above the 15 ppb federal lead action level, with several samples registering above 100 ppb.

Far more than pipes were corroded during the Flint water crisis. City, state, and federal missteps also destroyed residents’ trust in government agencies. Even if studies indicate Flint’s water is safe, it’s tough to expect its families to drink a glass of tap water without fear.

Fortunately, a majority of Americans have access to safe water, a luxury most of us probably enjoy with little thought. But Flint serves as a reminder that safe water isn’t a guarantee. A recent NRDC analysis found thousands of community water systems have violated federal drinking water laws, including the Lead and Copper Rule, which provides safeguards against lead. Meanwhile, there are many contaminants that aren’t even monitored or regulated, such as perchlorate (a component of rocket fuel) and PFOA/PFOS/PFAS (chemical cousins of Teflon).

To protect our water supplies, it is crucial that we upgrade our nationwide water infrastructure, prioritizing the replacement of an estimated 6.1 million lead service pipes. Strengthening existing government protections, including the Lead and Copper Rule, is also critical. Michigan is now leading the way , strengthening the state Lead and Copper Rule to require that all lead service lines be replaced within 20 years, among other provisions. Though not without flaws, the rule now gives the state the strongest lead drinking water protections in the country.

If you are concerned about your own drinking water , take a look at your water utility’s annual water quality report (also called a consumer confidence report), which is usually posted online and is required to disclose if contaminants have been found in your water. If contaminants have reached dangerous levels, the water supplier is required to send customers public notification. The EPA’s Safe Drinking Water Information System also maintains information about public water systems and their violations. You can go one step farther by having your water tested, either by your water supplier (which may provide this service for free) or by a certified lab.

If you discover your water is contaminated, one option is to use NSF-certified water filters that are designed to eliminate specific contaminants. It is most important, though, that you notify your water utility. If necessary, you can also contact your elected officials, your state’s drinking water program, or the EPA’s Safe Drinking Water Hotline (800-426-4791).

As NRDC President Rhea Suh noted at the height of the crisis, “When it comes to providing public services, few things are more fundamental than clean drinking water. What happened to the people of Flint should never have happened. Let’s make sure it doesn’t happen again.”

This NRDC.org story is available for online republication by news media outlets or nonprofits under these conditions: The writer(s) must be credited with a byline; you must note prominently that the story was originally published by NRDC.org and link to the original; the story cannot be edited (beyond simple things such as grammar); you can’t resell the story in any form or grant republishing rights to other outlets; you can’t republish our material wholesale or automatically—you need to select stories individually; you can’t republish the photos or graphics on our site without specific permission; you should drop us a note to let us know when you’ve used one of our stories.

Millions of old lead pipes contaminate drinking water in homes across the country.

Tell president biden to remove toxic lead water pipes quickly and equitably.

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Sources and Consequences of Groundwater Contamination

• Published: 02 January 2021
• Volume 80 , pages 1–10, ( 2021 )

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• Peiyue Li   ORCID: orcid.org/0000-0001-8771-3369 1 , 2 ,
• D. Karunanidhi 3 ,
• T. Subramani 4 &
• K. Srinivasamoorthy 5  

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Groundwater contamination is a global problem that has a significant impact on human health and ecological services. Studies reported in this special issue focus on contaminants in groundwater of geogenic and anthropogenic origin distributed over a wide geographic range, with contributions from researchers studying groundwater contamination in India, China, Pakistan, Turkey, Ethiopia, and Nigeria. Thus, this special issue reports on the latest research conducted in the eastern hemisphere on the sources and scale of groundwater contamination and the consequences for human health and the environment, as well as technologies for removing selected contaminants from groundwater. In this article, the state of the science on groundwater contamination is reviewed, and the papers published in this special issue are summarized in terms of their contributions to the literature. Finally, some key issues for advancing research on groundwater contamination are proposed.

Avoid common mistakes on your manuscript.

Groundwater is a major source of fresh water for the global population and is used for domestic, agricultural, and industrial uses. Approximately one third of the global population depends on groundwater for drinking water (International Association of Hydrogeologists 2020 ). Groundwater is a particularly important resource in arid and semi-arid regions where surface water and precipitation are limited (Li et al. 2017a ). Securing a safe and renewable supply of groundwater for drinking is one of the crucial drivers of sustainable development for a nation. However, urbanization, agricultural practices, industrial activities, and climate change all pose significant threats to groundwater quality. Contaminants, such as toxic metals, hydrocarbons, trace organic contaminants, pesticides, nanoparticles, microplastics, and other emerging contaminants, are a threat to human health, ecological services, and sustainable socioeconomic development (Li 2020 ; Li and Wu 2019 ).

Over the past three decades, chemical contamination is a common theme reported in groundwater studies. While groundwater contamination is a great challenge to human populations, this subject also presents a great opportunity for researchers to better understand how our subsurface aquifers have evolved and for decision makers to grasp how we can protect both the quality and quantity of these resources. Fresh water aquifers are one of the most important sections of the Critical Zone (CZ), which extends from the top of the vegetation canopy down to the bottom of the aquifer (Lin 2010 ). As part of the global effort to understand the functions, structures, and processes within the CZ, a range of investigations have been performed that contribute to our knowledge of the circulation and evolution of groundwater (Sawyer et al. 2016 ; Goldhaber et al. 2014 ).

Many of the contaminants in groundwater are of geogenic origin as a result of dissolution of the natural mineral deposits within the Earth’s crust (Basu et al. 2014 ; Pandey et al. 2016 ; Subba Rao et al. 2020 ; He et al. 2020a ). However, due to rapid expansion of the global population, urbanization, industrialization, agricultural production, and the economy, we now are faced with the challenge of the negative impacts of contaminants of anthropogenic origin. The countries most affected by these global changes are those that are going through rapid economic development, with many of them located in the eastern hemisphere (Clement and Meunie 2010 ; Hayashi et al. 2013 ; Lam et al. 2015 ). Thus, it is appropriate that this special issue entitled, “The fate and consequences of groundwater contamination” focuses on studies of the unique challenges related to contaminants of both anthropogenic and geogenic origin in groundwater in several countries in the eastern hemisphere, including China, India, Turkey, Bangladesh, Ethiopia, and Nigeria. Figure  1 illustrates the countries where the research was conducted and the classes of chemical contaminants reported in the articles in this special issue.

Eastern hemisphere, showing the countries where the groundwater research was conducted and the classes of contaminants studied in the articles published in this special issue

The range of topics included in articles in this special issue includes: (1) Latest methods for detecting and tracking the movement of groundwater contaminants; (2) Novel techniques for assessing risks to human populations consuming contaminated groundwater; (3) Effects of groundwater contamination on the abiotic environment, such as soil, sediments, and surface water; and (4) Case studies and remedial actions to control groundwater contamination from natural and anthropogenic sources. The co-editors of this special issue anticipate that these articles will facilitate an understanding of the origins and extent of groundwater contamination and its consequences and will provide examples of approaches that can be taken for remediation of groundwater contamination and protection of groundwater quality.

Major Contaminants

Groundwater contamination is defined as the addition of undesirable substances to groundwater caused by human activities (Government of Canada 2017 ). This can be caused by chemicals, road salt, bacteria, viruses, medications, fertilizers, and fuel. However, groundwater contamination differs from contamination of surface water in that it is invisible and recovery of the resource is difficult at the current level of technology (MacDonald and Kavanaugh 1994 ). Contaminants in groundwater are usually colorless and odorless. In addition, the negative impacts of contaminated groundwater on human health are chronic and are very difficult to detect (Chakraborti et al. 2015 ). Once contaminated, remediation is challenging and costly, because groundwater is located in subsurface geological strata and residence times are long (Wang et al. 2020 ; Su et al. 2020 ). The natural purification processes for contaminated groundwater can take decades or even hundreds of years, even if the source of contamination is cut off (Tatti et al. 2019 ).

The numbers of classes of contaminants detected in groundwater are increasing rapidly, but they can be broadly classified into three major types: chemical contaminants, biological contaminants, and radioactive contaminants. These contaminants can come from natural and anthropogenic sources (Elumalai et al. 2020 ). The natural sources of groundwater contamination include seawater, brackish water, surface waters with poor quality, and mineral deposits. These natural sources may become serious sources of contamination if human activities upset the natural environmental balance, such as depletion of aquifers leading to saltwater intrusion, acid mine drainage as a result of exploitation of mineral resources, and leaching of hazardous chemicals as a result of excessive irrigation (Su et al. 2020 ; Wu et al. 2015 ; Li et al. 2016 , 2018 ).

Nitrogen contaminants, such as nitrate, nitrite, and ammonia nitrogen, are prevalent inorganic contaminants. Nitrate is predominantly from anthropogenic sources, including agriculture (i.e., fertilizers, manure) and domestic wastewater (Hansen et al. 2017 ; He and Wu 2019 ; He et al. 2019 ; Karunanidhi et al. 2019 ; Li et al. 2019a ; Serio et al. 2018 ; Zhang et al. 2018 ). Groundwater nitrate contamination has been widely reported from regions all over the world. Other common inorganic contaminants found in groundwater include anions and oxyanions, such as F − , SO 4 2− , and Cl − , and major cations, such as Ca 2+ and Mg 2+ . Total dissolved solids (TDS), which refers to the total amount of inorganic and organic ligands in water, also may be elevated in groundwater. These contaminants are usually of natural origin, but human activities also can elevate levels in groundwater (Adimalla and Wu 2019 ).

Toxic metals and metalloids are a risk factor for the health of both human populations and for the natural environment. Chemical elements widely detected in groundwater include metals, such as zinc (Zn), lead (Pb), mercury (Hg), chromium (Cr), and cadmium (Cd), and metalloids, such as selenium (Se) and arsenic (As). Exposures at high concentrations can lead to severe poisoning, although some of these elements are essential micronutrients at lower doses (Hashim et al. 2011 ). For example, exposure to hexavalent chromium (Cr 6+ ) can increase the risk of cancer (He and Li 2020 ). Arsenic is ranked as a Group 1 human carcinogen by the US Environmental Protection Agency (EPA) and the International Agency for Research on Cancer (IARC), and As 3+ can react with sulfhydryl (–SH) groups of proteins and enzymes to upset cellular functions and eventually cause cell death (Abbas et al. 2018 ; Rebelo and Caldas 2016 ). Toxic metals in the environment are persistent and subject to moderate bioaccumulation when they enter the food chain (He and Li 2020 ; Hashim et al. 2011 ).

Organic contaminants have been widely detected in drinking water, and many of these compounds are regarded as human carcinogens or endocrine disrupting chemicals. In groundwater, more than 200 organic contaminants have been detected, and this number is still increasing (Lesser et al. 2018 ; Jurado et al. 2012 ; Lapworth et al. 2012 ; Sorensen et al. 2015 ). Some organic contaminants are biodegradable, while some are persistent. The biodegradable organic contaminants originate mainly from domestic sewage and industrial wastewater. Many of these organic substances are naturally produced from carbohydrates, proteins, fats, and oils and can be transformed into stable inorganic substances by microorganisms. They have no direct toxic effects on living beings but can reduce the dissolved oxygen levels in groundwater. Common organic contaminants include hydrocarbons, halogenated compounds, plasticizers, pesticides, pharmaceuticals, and personal care products and natural estrogens, among others (Lapworth et al. 2015 ; Meffe and Bustamante 2014 ). Many of the halogenated compounds (e.g., chlorinated, brominated, fluorinated) are stable in the environment and can be accumulated and enriched in organisms, causing harmful effects in organisms from higher trophic levels, including humans (Gwenzi and Chaukura 2018 ; Schulze et al. 2019 ). The persistent organic contaminants are mainly compounds used for agriculture, industrial processes, and protection of human health (Lapworth et al. 2015 ). Because these compounds degrade very slowly or even not at all, they may permanently threaten the quality of groundwater for drinking purposes (Schulze et al. 2019 ).

Radioactive contaminants in groundwater can originate from geological deposits of radionuclides but also can originate from anthropogenic sources, such as wastes from nuclear power plants, nuclear weapons testing, and improper disposal of medical radioisotopes (Dahlgaard et al. 2004 ; Lytle et al. 2014 ; Huang et al. 2012 ). Radioactive substances can enter the human body through a variety of routes, including drinking water. However, radioactive contaminants have been rarely detected in groundwater at levels that are a threat to human health.

Biological contaminants include algae and microbial organisms, such as bacteria, viruses, and protozoa. For microbial contaminants, more than 400 kinds of bacteria have been identified in human and animal feces, and more than 100 kinds of viruses have been recognized (Shen and Gao 1995 ). Some of these microbial organisms originate from natural sources, but some include microscopic organisms that co-exist with natural algal species and compete for available resources (Flemming and Wuertz 2019 ; Lam et al. 2018 ). Drinking water contaminated by microbial contaminants can result in many human diseases, including serious diarrheal diseases, such as typhoid and cholera. Currently, the COVID-19 virus has resulted in pandemic affecting every corner of the world. This coronavirus is primarily transmitted from person-to-person through respiratory droplets (Centers for Disease Control and Prevention 2020 ). However, water contaminated by this virus also can threaten human health (Bhowmick et al. 2020 ; Lokhandwala and Gautam 2020 ). Algal contamination is very common in surface waters, such as lakes and reservoirs due to eutrophication, but algae are rarely found at a high biomass in groundwater.

Consequences of Groundwater Contamination

Groundwater contamination can impact human health, environmental quality, and socioeconomic development. For example, many studies have shown that high levels of fluoride, nitrate, metals, and persistent organic pollutants are a health risk for human populations (Wu et al. 2020 ). This is especially critical for infants and children who are more susceptible to the effects of these contaminants than adults (He et al. 2020b ; Wu and Sun 2016 ; Karunanidhi et al. 2020 ; Mthembu et al. 2020 ; Ji et al. 2020 ; Subba Rao et al. 2020 ; Zhou et al. 2020 ). For example, “blue baby syndrome,” also known as infant methemoglobinemia, is caused by excessive nitrate concentrations in the drinking water used to make baby formulas. Human health also can be affected by the groundwater contamination through effects on the food production system. Irrigation with groundwater contaminated by heavy metals and wastewater containing persistent contaminants can result in the accumulation of toxic elements in cereals and vegetables, causing health risks to humans (Jenifer and Jha 2018 ; Yuan et al. 2019 ; Njuguna et al. 2019 ).

Groundwater contamination also can negatively affect the quality of lands and forests. Contaminated groundwater can lead to soil contamination and degradation of land quality. For example, in many agricultural areas in arid regions, high groundwater salinity is one of the major factors influencing soil salinization (Wu et al. 2014 ). The soluble salts and other contaminants, such as toxic metals, can accumulate in the root zone, affecting vegetation growth. Groundwater contaminants also can be transported by surface water-groundwater interactions, leading to deterioration of surface water quality (Teng et al. 2018 ).

Sustainable economic development requires a balance between the rate of renewal of natural resources and human demand (Li et al. 2017b ). Freshwater is probably the most valuable of the natural resources. However, chronic groundwater contamination may reduce the availability of freshwater, breaking the balance between water supply and demand and leading to socioeconomic crises and even wars. Water shortages induced by contamination may become a factor causing conflicts among citizens in the future (Schillinger et al. 2020 ), possibly delaying the socioeconomic development of a nation. Groundwater contamination is not only an environmental issue but also a social issue, demanding collaboration between both natural scientists and social scientists.

Articles in the Special Issue

Nineteen papers are included in this special issue. The topics of these papers cover a range of contamination issues, including the sources of geogenic and anthropogenic contamination, seasonal cycles in contamination, human health risks, and remediation technologies. Figure  2 illustrates a word cloud generated using the words in the titles and abstracts of the articles in this special issue, showing the most frequently used terms. The word cloud shows that the most frequently used technical terms in the articles are water, risk, metals, nitrate, fluoride, polycyclic aromatic hydrocarbons (PAHs), health, limits, and values. These terms reflect the main topics of the articles, which cover the assessment of the concentrations of trace metals, fluoride, nitrate, PAHs, and other organic contaminants in groundwater and the associated risks to the health of human populations. Some more minor terms, such as geogenic, source, removal, statistical, EWQI, and mobility, indicate that some articles focus on evaluating the sources of groundwater contamination, approaches to groundwater quality assessment, and contaminant remediation techniques. The main contributions of each article in this special issue are summarized below.

Word cloud generated using the words in the titles and abstracts of articles in this special issue

Toxic metals are persistent contaminants and can be bioaccumulated in human tissues via food chain (He and Li 2020 ). In this special issue, six articles focused on the assessing trace metal pollution in groundwater. Çiner et al. ( 2021 ) used multivariate statistical analysis to identify the sources of trace elements in groundwater, including Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, and Ba, and assessed the health risks from arsenic contamination in a region of south-central Turkey. Their research results indicate that the carcinogenic risks from exposure to arsenic to both adults and children were higher than the guideline limit, and the geogenic processes are the main cause of trace element contamination in groundwater in this region. Chandrasekar et al. ( 2021 ) also identified geogenic metal contamination in their article focused on the source, geochemical mobility, and health risks from trace metals in groundwater in a Cretaceous-Tertiary (K/T) contact region of India. However, Raja et al. ( 2021 ) concluded that industrial activities and leaching from municipal dumpsites were the main sources of the metal pollution in the groundwater in the industrialized township (Taluk) of Virudhunagar in India.

In addition to contamination of groundwater, trace elements can be transported via groundwater into surface waters and into oceans. In the article by Prakash et al. ( 2021 ), estimates were made of the submarine groundwater discharge and associated trace element fluxes from an urban estuary region to the marine environment in the Bay of Bengal in India. This study revealed that submarine groundwater discharge is an important factor contributing to the fluxes to the sea of dissolved trace elements.

Finding efficient and cost-effective technologies for removal of trace elements from groundwater is crucial for the sustainable management of water resources. Zhao et al. ( 2021 ) studied Cd removal from water using a novel low-temperature roasting technique associated with alkali to synthesize a high-performance adsorbent from coal fly ash. Dutta et al. ( 2021 ) proposed to use electrocoagulation with iron electrodes as a treatment technology for arsenic removal from groundwater, and a pilot scale filtration unit was used to remove ferric hydroxide flocs produced during the process.

Fluoride is of value in trace amounts for promoting dental health, but this anion is toxic when present in high concentrations in water and food (Adimalla and Li 2019 ; Li et al. 2014 , 2019b ; Marghade et al. 2020 ). In this special issue, two articles specifically address fluoride occurrence, distribution, and health risks. The article by Haji et al. ( 2021 ) describes a study of groundwater quality and human health risks from fluoride contamination in a region within the southern Main Ethiopian Rift. Keesari et al. ( 2021 ) used the empirical cumulative density function to estimate the health risks from consuming fluoride contaminated groundwater in northeastern parts of Rajasthan in India. These authors also produced a fluorosis risk map to aid decision makers in taking necessary remedial measures to improve the groundwater quality.

Organic pollutants, including polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), are common contaminants of anthropogenic origin in groundwater that could cause serious health problems. In this special issue, two articles focused on these organic pollutants. The article by Ololade et al. ( 2021 ) reported an investigation into PAHs and PCBs in groundwater near selected waste dumpsites located in two southwestern states in Nigeria. They found that the more water-soluble, low molecular weight-PAHs accounted for more than 61% of the total PAHs detected across all locations, but surprisingly the more highly chlorinated hexa-PCBs dominated the congener profiles. In another paper in this issue by Ambade et al. ( 2021 ), the occurrence, distribution, health risk, and composition of 16 priority PAHs were investigated in drinking water from southern Jharkhand in the eastern part of India. These authors found that lower and middle molecular weight PAHs were dominant in groundwater from the study area, but the levels are currently below concentrations that are a carcinogenic risk.

Studies of radioactive elements in groundwater often are neglected, but these radionuclides can be a hazard to human health. Adithya et al. ( 2021 ) conducted a study in Tamil Nadu state in southern India to measure the levels of radon (Rn) in groundwater and quantify the health risks. Their study showed that the Rn is released into groundwater from granitic and gneissic rocks within uranium-enriched lithological zones. However, the Rn levels determined in Bequerels per litre were lower than the guideline limit and the groundwater does not pose health risks to consumers.

In this special issue, Adimalla and Qian ( 2021 ) conducted a study on the spatial distribution and potential health risks from nitrate pollution in groundwater in southern India. The article revealed high nitrate levels in groundwater, at concentrations up to 130 mg/L. Both adults and children were judged to face health risks from consumption of nitrate in drinking water, but children were identified as more susceptible to the effects of groundwater nitrate pollution. The paper by Karunanidhi et al. ( 2021 ) describes the improvements in groundwater quality that occurred in an industrialized region of southeastern India between January and June of 2020. These improvements included reduced nitrate contamination, which may have been due to reduced transport of nitrate into groundwater before the monsoon period, but also could have been due to the decline in industrial and agricultural activity in the region during the lockdown in India that began in March 2020 in response to the first wave of the COVID-19 pandemic. In this study, fluoride concentrations of geogenic origin also were lower in groundwater before the monsoon.

Understanding the seasonal and spatial variations in groundwater quality is essential for the protection of human health and to maintain the crop yields. Subba Rao et al. ( 2021 ) used multiple approaches to identify the seasonal variations in groundwater quality and revealed that the groundwater quality for drinking and irrigation purposes was lower in the post-monsoon period relative to the pre-monsoon period. The deterioration of groundwater quality in the post-monsoon period was attributed to contaminant transport occurring through groundwater recharge but also was influenced by topographical factors and human activities.

Understanding the hydrogeochemical processes affecting groundwater chemistry is the basis for effective management of groundwater resources. Ren et al. ( 2021 ) adopted statistical approaches and multivariate statistical analysis techniques to understand the hydrogeochemical processes affecting groundwater in the central part of the Guanzhong Basin, China. The main contribution of this article is that it could help local decision makers to make water management decisions in the densely populated river basin by providing them with useful groundwater management options.

There are four articles in this special issue that focus specifically on methods to assess groundwater quality and humfluoride and associated arsenicosis and fluoan health risks. Shukla and Saxena ( 2021 ) assessed the groundwater quality and health risk in the rural parts of Raebareli district in northern India. Wang et al. ( 2021 ) identified the hydrochemical characteristics of groundwater and assessed health risk to consumers in a part of the Ordos basin in China. Adimalla ( 2021 ) applied two indices: the entropy weighted water quality index (EWQI), and the pollution index of groundwater (PIG) to assess the suitability of groundwater for drinking purpose in the Telangana state in southeastern India. Khan et al. ( 2021 ) assessed the drinking water quality and potential health impacts by considering physicochemical parameters, as well as bacteriological contamination of groundwater in Bajaur, Pakistan.

Collectively, these articles contribute to the literature on scientific developments in the field of groundwater contamination. The case studies presented in these articles are useful for policy makers and the public to understand the current water quality status in these regions. In particular, these articles provide a window into the groundwater contamination issues that are affecting low- and middle-income countries and countries with emerging economies in the eastern hemisphere. Researchers from Europe, North America, and other high-income countries often do not grasp the extent of groundwater contamination from geogenic and anthropogenic sources in these regions and do not realize that many human populations have no choice but to consume the contaminated drinking water.

The Way Ahead

Groundwater contamination is now a global problem and the resolution of these problems requires close collaboration among researchers in universities and government agencies, industries, and decision makers from all levels of government. To solve the groundwater contamination problems, international collaboration is needed. This is particularly true in countries with developing economies where financial resources and access to advanced technologies are not readily available. Special focus should be given to the following aspects of research and training:

Groundwater contamination issues in different countries should be addressed with a range of measures, techniques, and policies. Although groundwater contamination is a global problem, its nature and influencing factors are different between countries, climatic regions, and geological features. It may not be optimal to adopt remediation approaches that are successful in other countries or regions. For example, nitrate pollution is caused by fertilizer and manure applications in some agricultural regions (Zhang et al. 2018 ) but also may be caused by pollution by industrial and domestic wastewater in other areas, or even by explosives used in mineral exploration (Li et al. 2018 ). It may be necessary to use different approaches to mitigate different types of nitrate pollution. Even in instances where fertilizer application is the common cause of nitrate pollution in a tropical and a temperate region, the remediation approaches could be different, as climate factors and soil characteristics will have a great influence on the mechanisms and extent of contaminant transport.

With the rapid technological development, many novel techniques have been developed to study groundwater contamination, including geophysical and geoinformatics techniques. Geographical information systems (GIS) and remote sensing (Ahmed et al. 2020 ; Al-Abadi et al. 2020 ; Alshayef et al. 2019 ; Kannan et al. 2019 ) have accelerated the development of groundwater science. In the future, artificial intelligence, “big data” analysis, drone surveys, and molecular and stable isotope analysis technologies will be more widely available for applications in groundwater research. Groundwater scientists need to adopt and apply these new technologies for the study of groundwater contamination.

Governments, particularly in countries with developing economies need to invest in and encourage research and training in groundwater science. In many regions, human populations have no alternative but to consume groundwater that is contaminated with chemical or biological agents, potentially causing wide ranging health effects. Investment is needed to determine the extent of this contamination and how to remediate the impacts on human health, or to find alternate sources of drinking water.

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Acknowledgements

Editing a successful special issue is not easy. The Guest Editors must ensure that the topic is of importance and of broad interest so that there are an adequate number of contributors willing to submit their manuscripts. They must also make sure that the peer review process is efficient and effective, while maintaining the high quality of the papers. All of these cannot be fulfilled without the support of the Editor in Chief. So, we are extremely grateful for Prof. Chris Metcalfe’s guidance and support for this special issue. We are also sincerely thankful to the reviewers who provided constructive comments that are essential for maintaining the high quality of the special issue. Last but not the least, the authors whose manuscripts were included and those whose manuscripts were rejected are acknowledged for their interest in contributing to the special issue. The special issue was edited in a situation in which the COVID-19 struck in nearly every corner of the world. We are impressed by the dedication of doctors who fought and/or are fighting against the coronavirus. Prof. Peiyue Li is grateful for the financial support granted by the National Natural Science Foundation of China (41761144059 and 42072286), the Fundamental Research Funds for the Central Universities of CHD (300102299301), the Fok Ying Tong Education Foundation (161098), and the Ten Thousand Talents Program (W03070125), which allow him to carry out various investigations. The year 2021 is the 70th anniversary of Chang’an University. Congratulations!

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Li, P., Karunanidhi, D., Subramani, T. et al. Sources and Consequences of Groundwater Contamination. Arch Environ Contam Toxicol 80 , 1–10 (2021). https://doi.org/10.1007/s00244-020-00805-z

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Clinical encounter with three cancer patients affected by groundwater contamination at Camp Lejeune: a case series and review of the literature

• Kyungsuk Jung   ORCID: orcid.org/0000-0003-1306-5180 1 ,
• Aziz Khan 1 ,
• Robert Mocharnuk 1 ,
• Susan Olivo-Marston 2 &
• Justin T. McDaniel 3  

Journal of Medical Case Reports volume  16 , Article number:  272 ( 2022 ) Cite this article

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Advanced understanding of tumor biology has recently revealed the complexity of cancer genetics, intra/inter-tumor heterogeneity, and diverse mechanisms of resistance to cancer treatment. In turn, there has been a growing interest in cancer prevention and minimizing exposure to potential environmental carcinogens that surround us. In the 1980s, several chemical carcinogens, including perchloroethylene (PCE), trichloroethylene (TCE), and benzene, were detected in water systems supplying Camp Lejeune, a US Marine Corps Base Camp located in North Carolina.

Case presentation

This article presents three cases of cancer patients who have lived at Camp Lejeune, and, decades later, came to our clinic located 1000 miles from the original exposure site. The first patient is a young Caucasian man who was diagnosed with T cell acute lymphoblastic leukemia at the age of 37, and the second patient is a Caucasian man who had multiple types of cancer in the prostate, lung, and colon as well as chronic lymphocytic leukemia in his 60s and 70s. The third patient is another Caucasian man who had recurrent skin cancers of different histology, namely basal cell carcinomas, squamous cell carcinomas, and melanoma, from his 50s to 70s.

Conclusions

The US Congress passed the Honoring America’s Veterans and Caring for Camp Lejeune Families Act in 2012, which covers appropriate medical care for the people affected by the contamination. We hope that this article raises awareness about the history of Camp Lejeune’s water contamination among cancer care providers, so the affected patients can receive appropriate medical coverage and cancer screening across the country.

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Camp Lejeune is a US Marine Corps Base Camp covering 256 square miles on the Atlantic Seaboard in Onslow County, North Carolina. Since its establishment in 1942, it has provided training facilities and barracks for recruits as well as housing units for enlisted personnel and their families. The camp also contains nonresidential facilities such as administrative offices, hospitals, schools, day-care centers, and recreational sites. It is estimated that approximately 170,000 active-duty personnel, family members, and civilian employees live in or around the camp at any given time [ 1 ].

In August 1982, a routine water sample screening at one of the water treatment plants in the camp detected high levels of halogenated hydrocarbons [ 2 ]. Subsequent analysis confirmed that these included perchloroethylene (PCE), trichloroethylene (TCE), and their degradation products—dichloroethylene (DCE) and vinyl chloride. The levels of these compounds were well above the maximum contaminant levels (MCL) of 5 parts per billion (ppb; µg/L) which is determined by the US Environmental Protection Agency (EPA). Further investigation in 1985 revealed that several water-supply wells which collected groundwater were the sources of contamination. It was postulated that the contaminants leached into the water-supply wells from underground water tables, and were subsequently pumped into the water treatment plants where the water was mixed and eventually distributed to both residential and nonresidential portions of the camp. The contaminated wells supplied water to Tarawa Terrace and Hadnot Point, but the Hadnot Point water system was also responsible for distributing water to housing on Holcomb Boulevard until 1972, and then intermittently thereafter (Fig. 1 ). The contaminated water-supply wells were eventually shut down from February to April 1985.

Source Maslia ML. Expert Panel Assessing ATSDR’s Methods and Analyses for Historical Reconstruction of Groundwater Resources and Distribution of Drinking Water at Hadnot Point, Holcomb Boulevard, and Vicinity, U.S. Marine Corps Base Camp Lejeune, North Carolina. Prepared by Eastern Research Group, Inc., Atlanta, GA. Prepared for Agency for Toxic Substances and Disease Registry (ATSDR), Atlanta, GA. April 29–30, 2009; p. 149.

Map of Camp Lejeune and the water distribution areas.

In April 1985, the North Carolina Department of Natural Resources and Community Development (NCDNRCD) analyzed water samples taken from the affected water-supply wells plus the monitoring wells installed for the remedial investigation. This information, combined with underground water table data that indicated a southeast direction of water flow, narrowed the contamination source to an off-base dry-cleaner [ 3 ]. The dry-cleaning establishment was geographically located on the northwest edge of the PCE plume and in close proximity to several of the water-supply wells servicing Tarawa Terrace. The owner of the business stated in a deposition that the cleaner had routinely used PCE for dry-cleaning since it opened its business in 1953 [ 4 ]. He indicated that PCE was used as a solvent for clothes as they were spun in the wheel of the dry-cleaning machine. He also stated that the waste product was gathered in powder form and was used to fill potholes. This contamination scenario was corroborated by an extremely high level of PCE from a monitoring well that was installed close to the dry-cleaning facility [ 5 ].

Other volatile organic compounds (VOC) were also potentially involved. Personnel from the US Geological Survey (USGS) reported a “strong gasoline odor” at one of the water-supply wells during a routine reconnaissance in October 1986 [ 5 ]. A review of records traced it back to various gasoline leaks and spills from underground storage tanks located near the Tarawa Terrace shopping center. Several buildings with underground storage tanks were identified in the vicinity that served as gasoline stations [ 2 ]. Of note, there was an accidental discharge of 4400 gallons of unleaded gasoline to the subsurface on September 21, 1985, and leakage of a 3000-gallon tank of leaded gasoline on July 23, 1986 [ 2 ]. In addition, a more comprehensive assessment of the local contamination and toxic release history suggested that small leaks of gas probably started in the 1950s [ 5 ]. As of May 4, 1987, it was estimated that there was more than 2 feet of floating gasoline above the water table around the Tarawa Terrace shopping center [ 6 ]. Compared to Tarawa Terrace, the water-supply contamination scenario for Hadnot Point was more complex. There were multiple potential sources of pollutants surrounding the Hadnot Point supply wells, including hazardous waste sites, fire training areas, and industrial storage lots. Several pieces of evidence suggested that the magnitude of groundwater contamination was much more extensive at Hadnot Point than at Tarawa Terrace [ 5 ].

Currently, most of the marines and their families who once lived at Camp Lejeune during the affected period have moved to different areas of the United States, and they now carry a high risk of developing cancers that are potentially associated with the abovementioned chemical carcinogens. In this article, we present the cases of three patients who lived at Camp Lejeune and developed a rare type or multiple different types of cancers decades later. Then, we review epidemiological studies that examined associations between the chemicals found in the Camp Lejeune water supply and specific cancer types. We hope that this report will raise awareness of water contamination as an important source of carcinogenesis among cancer care providers as well as the general public.

The first patient is a 37-year-old Caucasian man who had been relatively healthy until he presented with severe fatigue and muscle ache that persisted for several months. He visited his primary care doctor, and a complete blood count (CBC) revealed a high leukocyte count and the presence of peripheral blasts. When he was sent to an emergency room, his total white blood cell (WBC) count was recorded at 20.5 k/mm 3 , hemoglobin was 11.6 g/dL, and the platelet count was 146 k/mm 3 . He underwent a bone marrow biopsy that revealed hypercellular marrow with involvement of T lymphoblastic leukemia. Cytogenetic and molecular analysis was positive for del 11q23 ( KMT2A ), and rearrangement of 14q32 ( IGH ). BCR-ABL minor fusion transcript (p190) was detected in a qualitative test, but it was not detected in a quantitative test. The discrepancy was due to a very low level of BCR-ABL fusion in the specimen. Hence the mutation was unlikely a pathogenic driver. Fortunately, there was no evidence of central nervous system (CNS) involvement.

His father was a marine, and their family moved to Camp Lejeune in April 1985. The patient was 20 months old when they moved there, and they lived in Tarawa Terrace until 1992. When he grew up, he served in the Marine Corps himself from 2003 to 2008. After discharge, the patient had different jobs, but he had no known occupational exposure to hazardous chemicals. The patient and his family were made aware of the water contamination problem at Camp Lejeune when they received a letter from the US Navy in 2012. He never smoked and does not drink alcohol. He developed anxiety after the diagnosis of leukemia but had no other comorbidities. There is no family history of malignancy to his knowledge. He has one brother, who was in utero when the family moved to Camp Lejeune, and his brother has not been diagnosed with any cancer so far.

The patient was started on the Linker regimen for T cell acute lymphoblastic leukemia (ALL). Following completion of induction chemotherapy (cycle 1A), a bone marrow biopsy was normocellular, with mature tri-lineage hematopoiesis. Repeat next-generation sequencing (NGS) was negative for any genetic mutation, indicating no measurable residual disease (MRD). The patient received cycles 1B, 1C, 2A, and 2B of the Linker regimen, and then underwent an allogeneic stem cell transplant. He tolerated the procedure well, and his leukemia remains in complete remission.

The second patient is a Caucasian male who has been diagnosed with multiple different types of cancer. He was first diagnosed with prostate adenocarcinoma at the age of 68 after presenting with elevated prostate-specific antigen (PSA) of 4.5 ng/mL. An ultrasound-guided biopsy of a 1 cm nodule in the left lobe was positive for clinical-stage T2aN0 prostate adenocarcinoma. The Gleason score was 3 + 4, and the tumor involved 10% of the biopsy specimen. He underwent brachytherapy with the implantation of iodine-125 seeds. And, at age 74, he was diagnosed with colon adenocarcinoma. A large ascending colon mass was found on a computed tomography (CT) scan during a workup for unexplained anemia. Subsequently, he underwent a right hemicolectomy for a high-grade, poorly differentiated pT4bN0 tumor. After surgery, he received adjuvant FOLFOX chemotherapy and has remained colon cancer-free per radiographic imaging and endoscopic surveillance. He was also diagnosed with lung cancer at the age of 75. A series of CT scans detected a slowly but progressively enlarging mass in the right upper lobe of the lung. When it was brought up as a worrisome finding, the size of the tumor was 10 × 13 mm. He declined to undergo biopsy due to the high risks of the procedure, opting instead for a positron emission tomography (PET) scan. This study confirmed the presence of the right upper lobe pulmonary nodule with a measured standardized uptake value (SUV) of 8.8. After an interdisciplinary discussion, the consensus decision was to obliterate the mass with stereotactic body radiation therapy (SBRT). The patient received a protracted course of 12 fractions of radiation at ×400 cGy per dose, and there has been no evidence of recurrent disease since then.

At the age of 78, he was diagnosed with chronic lymphocytic leukemia (CLL). He had intermittent thrombocytopenia for several years, but workup for the lymphoproliferative disease was negative. However, a recent bone marrow biopsy was positive for kappa monotypic B cells, consistent with CLL. Then, the patient developed Evans syndrome with progressive thrombocytopenia and hemolytic anemia. He was initially treated with rituximab plus prednisone. However, without improvement in the cell counts, the treatment was subsequently switched to a single-agent ibrutinib. After the switch of therapy, his blood counts have stabilized.

This patient was stationed at Camp Lejeune from 1962 to 1987 as an enlisted marine. He lived in a trailer park in Camp Johnson, formerly named Camp Knox. He has been an occasional pipe smoker for about 20 years but had no other exposure to toxic chemicals except for the contaminated water supply. He does not drink alcohol. Although an association is less clear, he and his wife had difficulty conceiving additional children for 10 years after the birth of their first child. His other comorbidities include coronary artery disease requiring stent placement, type 2 diabetes, and depression. There is no one else in the family who had cancer as far as he knows.

The third patient is a 77-year-old Caucasian man who has a history of recurrent nasal papilloma and multiple skin cancers. He developed a severe de novo allergy while living at Camp Lejeune. Since then, he has undergone multiple surgical resections for recurrent inverted nasal papilloma. In addition, he has received nitrous oxide cryotherapy and repeated surgical resections for multiple and recurrent basal cell carcinomas and squamous cell carcinomas of the skin. Most recently, at the age of 77, he was diagnosed with melanoma of the right supraclavicular chest for which he underwent wide local excision with clear margins.

He lived at Camp Lejeune while serving as an active-duty marine for 2 years from 1967 to 1968. During the first year, he lived in a barrack in the division headquarters, located at Hadnot Point. During his second year, he and his wife moved to a married housing unit in Tarawa Terrace. Following his discharge from the service, he worked in a suture and contact lens manufacturing factory at Johnson & Johnson, but he denied any occupational exposure to chemicals or toxins. He is a never-smoker and drinks alcohol occasionally. He has a medical history of atrial fibrillation, coronary artery disease, obstructive sleep apnea, and interstitial pulmonary fibrosis. His mother, who was a heavy smoker, died of lung cancer, but no one else in his family has had cancer. Timelines of events for each patient are summarized in Table 1 .

A review of epidemiological studies

Sir Bradford Hill proposed nine criteria for determining an association between a cause and a disease.[ 7 ] Realistically, the assessment of potential carcinogens is heavily reliant upon epidemiological data due to a long latency period from the initial exposure to the development of cancer. Moreover, some cancers occur at a relatively low frequency, requiring long-term monitoring of a large cohort. Nonetheless, there have been several case–control and ecological studies that have suggested an association between the contaminants found in the Camp Lejeune water supply and several different cancers. However, these results must be interpreted cautiously, as there are inherent limitations in the retrospective analyses of such large datasets. Among the studies presented here, the strength of association may vary for the same chemical because different assumptions were made when calculating group exposures based on histological data. The possibility of co-contaminants confounding the health of affected individuals also cannot be ruled out. Being mindful of these unavoidable limitations, we review the following analyses of large patient cohorts that have been thoroughly studied using rigorous standards.

PCE and TCE

PCE (also known as “perc”) and TCE are both halogenated solvents widely used for industrial purposes (Fig. 2 ). They are colorless, noninflammable, and volatile liquids with an ether-like odor. The vapor from PCE and TCE is heavy, and it readily contaminates ambient urban air. These chemicals are used for dry-cleaning, textile processing, and metal degreasing, and as feedstock in the production of chlorinated chemicals [ 8 , 9 ]. PCE is relatively stable in its natural state, but it decomposes slowly in contact with moisture. Thus, PCE, TCE, and their by-products, DCE and hydrogen chloride, are commonly found as co-contaminants. These molecules can be absorbed by humans via inhalation or ingestion of contaminated vapor or water, whereas dermal absorption is considered a minor route [ 10 ]. PCE and TCE have been classified as probable and known human carcinogens, respectively, by the US EPA, and thus the goal is to achieve zero public exposure. However, the MCL was set at 5 ppb (µg/L) for both PCE and TCE because this is the lowest concentration that is reliably detectable [ 11 ]. The Agency for Toxic Substances and Disease Registry (ATSDR) has developed the Hazardous Substance Release and Health Effects Database (HazDat) to collect public health data and compile lists of contaminants specific to known hazardous waste sites. In this database, the most frequently found single-agent contaminant in groundwater was TCE (42.4%), and the most frequently found combination of substances was TCE and PCE (23.5%) [ 12 ].

Chemical structures of a PCE and b TCE

In 1976 and 1978, high levels of PCE were detected in two different areas of Rhode Island by the US EPA, and vinyl liners inside the water distribution pipe were identified as the source of contamination. The vinyl-lined pipes were installed in the 1960s to treat water acidity, and the inner surface of the pipe was coated with vinyl toluene resin in which the solvent used was PCE [ 13 ]. This discovery prompted an inspection of water pipes in other states of New England, and an investigation by Massachusetts revealed that a considerable length of the problematic pipes was installed in the upper Cape Cod area, including Barnstable, Bourne, Falmouth, Mashpee, and Sandwich. In certain sites in Falmouth, where water flow was low, the level of PCE reached as high as 18,000 ppb [ 14 ]. By the early 1980s, either the affected taps were closed or the pipes were flushed to reduce the PCE concentrations below 40 ppb as a remedial action. Several years after the contamination was first identified, a significantly higher incidence of cancers was observed in towns located in upper Cape Cod relative to the entire state, which occurred in breast, colorectal, lung, and hematopoietic organs [ 15 ]. Several case–control studies were subsequently published. One study by Paulu et al. calculated estimated doses of exposure for the involved population based on the residence history, water flow characteristics, pipe age, and dimensions. For people whose exposure level was over the 90th percentile, the adjusted odds ratio (OR) for lung cancer (adjusted for sex, age, other chemical exposures, smoking status, and comorbidities) was elevated at 6.2 [95% confidence interval (CI) 1.1–31.6] after a 7-year latency period, and at 19.3 (95% CI 2.6–141.7) after a 9-year latency period [ 16 ]. Another study by Aschengrau et al. observed an elevated adjusted OR for leukemia among those whose exposure level was over the 90th percentile (OR 8.33, 95% CI 1.53–45.29 without latency; OR 5.84, 95% CI 1.37–24.91 with latency) [ 17 ].

Another incidence of water contamination with PCE and TCE was reported in 2002 in the city of Redlands in San Bernardino County, California. Water sample tests and hydrogeological studies from this area indicated that the PCE contamination in the water-supply wells began as early as 1980, with levels ranging from 5 to 98 ppb. TCE contamination likely occurred a decade earlier, with levels ranging between 0.09 and 97 ppb [ 18 ]. In 1991, the affected wells were removed from the water system, and the water was treated to reduce the concentrations of PCE and TCE. One ecological study calculated standardized incidence ratios (SIRs) of different cancer types in the affected area from 1988 to 1998, based on the actual incidence compared with the expected number of cancers. This study found that the incidence of melanoma and uterine cancer was significantly elevated in the Redlands area during those 10 years, with lower ends of a 99% CI above 1.0 (SIR 1.42, 99% CI 1.13–1.77 for melanoma; SIR 1.35, 99% CI 1.06–1.70 for uterine cancer). However, the prudent authors could not rule out possible confounding effects and stated that distinct area-related socioeconomic status could have impacted their level of healthcare access and vigilance to health-related issues [ 18 ].

In New Jersey, routine semi-annual water testing for VOCs became mandatory in 1984. Test results in 1984 and 1985 revealed detectable levels of non-trihalomethane (THM) VOCs, namely PCE, TCE, DCE, and 1,1,1-trichloroethane (TCA), in part of the water systems supplying 20% of the state’s population. An ecological study performed in 1990 in the potentially affected area reported an elevated SIR for leukemia in males (SIR 1.53, 95% CI 1.02–2.21). In this analysis, however, the contaminants were measured as a group of chemicals (non-THM VOC) and not individually, and the total level was only moderately elevated between 37 and 72 ppb [ 19 ]. A cohort study in 1994 categorized different levels of TCE in New Jersey water systems based on historical monitoring data in 1978–1984 and mandatory testing results in 1984–1985 and examined differences in rates of hematological malignancies. This study confirmed that the rates of non-Hodgkin’s lymphoma and leukemia were elevated in towns where the average level of TCE was 0.1–5.0 ppb or > 5.0 ppb. However, a dose–response relationship was not so evident, likely because the exposure levels were broadly stratified into < 0.1, 0.1–5.0, and > 5.0 ppb. For patients diagnosed with acute lymphocytic leukemia, for example, the age-adjusted ratio was higher for the 0.1–5.0 ppb exposure level than it was for the > 5.0 ppb level. However, when assessing all types of leukemia, there was a tendency for an increased rate with higher levels of exposure. For males, the age-adjusted rate ratio (RR) was 0.85 (95% CI 0.71–1.02) for the exposure level of 0.1–5.0 ppb, which increased to 1.10 (95% CI 0.84–1.43) for the exposure level of > 5.0 ppb. For females, the association was stronger. The age-adjusted RR was 1.13 (95% CI 0.93–1.37) for the exposure level of 0.1–5.0 ppb and 1.43 (95% CI 1.07–1.90) for the exposure level of > 5.0 ppb. Assuming the validity of this positive association, females were more likely to be diagnosed with leukemia than males. This suggests that sex differences may also play a role in the pathogenesis of leukemia following exposure to these chemicals [ 20 ].

Based on the knowledge obtained from laboratory research and epidemiological data, the World Health Organization’s (WHO) International Agency for Research on Cancer (IARC) and the US EPA provide hierarchal classification systems for potential carcinogens (Additional file 1 : Tables S1, S2). The IARC and the US EPA have classified PCE as a group 2A and a group B carcinogen, respectively, or “probable human carcinogen” [ 21 , 22 ]. TCE was classified as a group 1 carcinogen, “carcinogenic to humans,” per IARC standards, and a group A, that is, a “known human carcinogen,” by the US EPA standards [ 22 , 23 ].

Benzene is a hexagonal aromatic hydrocarbon that is volatile and highly flammable (Fig. 3 ). It evaporates quickly in room air and emits a unique gasoline-like odor. The vapor is heavier than air, and the liquid form floats on water. It is one of the most widely used chemicals in the United States, and functions as a solvent as well as an intermediate substrate in the various chemical production of plastics, synthetic fibers, rubbers, dyes, and drugs. Benzene is produced naturally in volcanoes and forest fires but is more commonly found in crude oil extracts and produced in the oil-refining process [ 8 ]. The general public can be exposed to low levels of benzene from automobile exhaust or industrial emissions. Cigarette smoking is also a major source of benzene exposure in the USA. Rarely, leakage from underground gasoline storage tanks or hazardous waste sites can contain benzene and contaminate drinking water, like what probably happened at Camp Lejeune [ 24 ]. Based on EPA guidelines, the MCL of benzene is 5 ppb, although the maximum contaminant level goal (MCLG) is zero [ 11 ]. In the HazDat database by ATSDR, benzene was the most frequently found air contaminant (6.0%) and the fourth most frequently found water contaminant (25.8%) in hazardous waste sites [ 12 ].

Chemical structure of benzene

The adverse health effects of chronic benzene exposure are well known, especially hematopoietic toxicities. Animal studies have demonstrated that exposure to benzene is associated with pancytopenia and aplastic anemia as well as chromosomal changes [ 25 , 26 ]. Different types of skin, gastrointestinal epithelium, liver, respiratory tract, and bone marrow tumors were observed in mice after either prolonged ingestion or inhalation of benzene [ 27 ]. The carcinogenicity of benzene was also established in human studies on exposed workers. One of the most extensively studied populations is the rubber hydrochloride workers, the so-called Pliofilm cohort. Exposure to benzene in this cohort occurred at rubber film manufacturing plants in Ohio from the 1930s to the 1970s. During the manufacturing process, the natural rubber was dissolved in benzene and was thinly spread on a conveyer belt. The benzene was then evaporated for recycling, and the rubber film was rolled and recovered from the conveyor belt. Rubber production took place at three different sites in Ohio. In one plant, workers were exposed from 1939 to 1976, and in the other two plants, exposure occurred from 1936 until 1965 [ 28 ]. Rinsky et al. meticulously estimated the individual risk of exposure based on company personnel records and past environmental measurements [ 29 ]. They reviewed job titles and types of work in the rubber hydrochloride plants to determine “exposure classes,” and combined these data with employment periods and the results of past industrial-hygiene measurements to calculate estimated exposure levels. Then they reviewed the vital status of the employees who worked at one of the three plants for at least 1 day between 1940 and 1965. Deaths were captured as an outcome after January 1, 1950, or earlier if the cumulative personal exposure to benzene reached at least 1 ppm-day (1 day of exposure). As a result, a total of 1165 white men were included in the cohort, contributing to 31,612 person-years at risk. Among these, 330 people died, out of which 15 people had died of lymphatic or hematopoietic cancers as of December 31, 1981. Standardized mortality ratios (SMRs) for both leukemia and multiple myeloma were significantly elevated (SMR 3.37, 95% CI 1.54–6.41 for leukemia; SMR 3.09, 95% CI 1.10–10.47 for multiple myeloma). When the cohort was divided into different exposure strata, there was a progressively increasing dose–response relationship for leukemia, but not for multiple myeloma. In an individually matched nested case–control analysis, it was confirmed that both cumulative dose and duration of exposure were higher for those diagnosed with leukemia and myeloma. Paustenbach et al. considered additional factors in the exposure assessment, including short-term, high-level exposures to vapors, background concentrations in the building, and dermal absorption. These additional exposures significantly increased the estimated total absorption, which was 3–5 times as high [ 30 ]. In an updated analysis that added 6 years of observation to the Pliofilm cohort, an additional five cases of leukemia were reported, and there were no additional cases of multiple myeloma. While it was suggested that a higher concentration of benzene was required for leukemogenic potential, the more general association between benzene exposure and leukemia was confirmed [ 31 ].

In China, a national occupational survey was carried out in 1981 which reported that more than 500,000 workers in 28,808 factories throughout the country were exposed to various levels of benzene between 1979 and 1981. In this report by Yin et al. , the investigators found a higher number of acute or chronic benzene poisoning cases among workers of shoemaking factories where benzene was mixed in the adhesive [ 32 ]. Subsequently, they monitored the cancer mortality rate among 28,460 workers who worked for at least 6 months in factories where benzene was used for painting, shoe manufacturing, rubber production, or adhesive production. Compared with workers in factories with no evidence of benzene, radiation, or other known carcinogen exposure, SMRs were elevated for leukemia, lung cancer, primary hepatocarcinoma, and stomach cancer [ 33 ]. After these reports, the Chinese Academy of Preventive Medicine (CAPM) collaborated with the US National Cancer Institute (NCI) to expand the analysis and consolidate the assessment, employing qualitative evaluation of the exposure. This analysis included 74,828 benzene-exposed workers from 1972 through 1987 in 672 factories in China and a control group of workers from workplaces where benzene was not used during the same period. The time-weighted average of benzene exposure was estimated by local industrial hygienists and occupational health personnel using measurements of historical ambient benzene levels combined with production and process information for the specific job title in each factory. This updated analysis confirmed that the incidence rate of hematological neoplasms was significantly elevated after benzene exposure. For the workers with estimated average exposure of ≥ 25, RR for all hematological neoplasms was 2.8 (95% CI 1.4–5.7). Moreover, the dose–response relationship was evident with the p -value for trend < 0.5, when the average exposure was divided into < 10, 10–24, and ≥ 25 [ 34 ].

Human data supporting benzene carcinogenicity after oral absorption are relatively scarce. Nonetheless, an accumulating number of studies report that water contamination by benzene does occur. For example, benzene was detected in service lines supplying drinking water to standing structures after the record California wildfire in 2018 [ 35 ]. The risk of water contamination with benzene is associated with human activities as well. Hydraulic fracturing is used at an increasing frequency for the cost-effective extraction of natural gas, but this process requires the injection of a large amount of water containing chemical additives. The risk of benzene exposure occurs when the flowback water returns to the surface, laced with the remaining additives, solvents, and petroleum-derived hydrocarbons. One study found that the benzene level increased to 148 ppb in a water sample obtained from a reservoir near coal-bed methane fracturing well sites in Sullivan County, Indiana [ 36 ]. In addition, there was a report of contaminated water on a container ship, attributed to the internal coating of the water tank [ 37 ], and there was a detectable level of benzene with other organic pollutants and organophosphorus pesticides in water reservoirs in the Haihe river basin of China [ 38 ]. In the District of Columbia, there was a cluster of leukemia-associated deaths that mysteriously occurred among the mechanics working in the Department of Public Works from 1990 to 1992. In a survey conducted to characterize exposure to carcinogens, the mechanics reported that they used petroleum to clean parts and wash their hands. They also admitted to occasionally siphoning petrol by mouth, resulting in possible oral absorption of benzene [ 39 ].

Based on the large volume of evidence characterizing benzene as a carcinogen in both animals and humans, IARC categorized benzene as a group 1 carcinogen, “carcinogenic to humans.” Under the US EPA classification, benzene is a “known carcinogen to humans,” group A. Although human data are relatively lacking for oral carcinogenicity, the US EPA has extrapolated cancer risk from the inhalation data to oral absorption [ 24 ].

Health effects of water contamination in Camp Lejeune

After the revelation about water contamination in Camp Lejeune in 1985, multiple scientific and health investigations ensued. In 2009, the National Research Council convened a “Committee on Contaminated Drinking Water at Camp Lejeune” and released a comprehensive report on the incident. This report illustrates contamination scenarios based on groundwater models, provides exposure assessment, and reviews relevant toxicology and epidemiological studies [ 5 ]. TCE and PCE contamination was the primary interest of this report, since sampling data were available for retrospective review for these chemicals. These data repeatedly supported high levels of contamination in the supply wells and mixed water supplies. At Hadnot Point, the level of TCE in mixed water reached 1400 ppb, with a mean level of 399 ppb from 1980 to 1985. However, there was a relative lack of focus on other organic compounds, especially benzene. Benzene was detected in water samples collected at the Tarawa Terrace water treatment plant in 1985, albeit in a small amount (< 5 ppb). In the Hadnot Point water system, a significant level of benzene was detected in several supply wells, with the maximum value reaching 720 ppb in 1984. Data before 1980 were not available. It is unknown whether the high concentration of benzene in the wells reached the tap water, because the water from the supply wells was pumped to the treatment center and mixed before distribution, and the wells were cycled on and off to allow only a few wells to operate at any given time. Available records indicate that benzene has not been detected in the mixed water samples since 1980, but the data were missing in 38 out of the 52 mixed water samples from the Hadnot Point water system during the testing period from 1980 to 1985 [ 2 ]. Despite the missing data, there were reasons to suspect benzene leakage into the water supply because of multiple potential sources of pollutants in these areas, including industrial dumpsites, transformer storage lots, fire training areas, liquids disposal areas, and fuel tanks [ 5 ].

Large-scale cohort studies were conducted for the enlisted personnel and civilian employees who resided or worked at Camp Lejeune during the affected period. The first study published in 2014 by Bove et al. examined a cohort of 154,932 Marine and Naval personnel who were stationed at Camp Lejeune at any time between April 1975 and December 1985. The cancer mortality rate in this cohort was compared with that of a comparison cohort which consisted of 154,969 Marine and Navy personnel who were stationed in the same period at Camp Pendleton in southern California where there was no evidence of water contamination. Demographic and social/educational characteristics were comparable between the two cohorts. Hazard ratios (HRs) were calculated using Cox regression models adjusted by sex, race, rank, and education. When the base location was used as a dichotomous variable, with no regard to cumulative exposure, the HR for all-cancer mortality was elevated at 1.1 in the Camp Lejeune cohort, with a p -value of 0.02. However, the p -value was > 0.10 for any specific type of cancer mortality. Another statistical analysis that was used in this study was to include the estimated cumulative exposure as a time-varying variable. Cumulative exposure was calculated based on monthly average contaminant concentrations in the water system of each individual’s primary residence and the occupancy dates. The investigators found that higher levels of cumulative exposure to the total VOCs, which is the sum of all contaminants (TCE, PCE, trans-1,2-dichloroethylene, vinyl chloride, and benzene), were associated with elevated kidney cancer-specific mortality, and a dose–response relationship was also found in TCE and benzene with Hodgkin’s lymphoma-specific mortality [ 40 ]. For a more focused interpretation of these results, the authors created a list of cancers of primary interest, based on previous health outcomes of water contamination in Cape Cod, Massachusetts, and New Jersey. These included kidney cancer, bladder cancer, liver cancer, esophageal cancer, cervical cancer, and hematopoietic malignancies [ 16 , 17 ]. In this list, the disease-specific mortality was elevated in the Camp Lejeune cohort for kidney cancer (HR 1.35, 95% CI 0.84–2.16), liver cancer (HR 1.42, 95% CI 0.92–2.20), esophageal cancer (HR 1.43, 95% CI 0.85–2.38), Hodgkin’s lymphoma (HR 1.47, 95% CI 0.71–3.06), multiple myeloma (HR 1.68, 95% CI 0.76–3.72), leukemia (HR 1.11, 95% CI 0.75–1.62), and cervical cancer (HR 1.33, 95% CI 0.24–7.32). Among those cancers with elevated HR, there was evidence of a dose-related effect in kidney cancer, cervical cancer, leukemia, and Hodgkin’s lymphoma, as they occurred primarily or exclusively in people with higher cumulative exposure [ 40 ].

A second study by the same authors looked at a different cohort affected by the contamination at Camp Lejeune. The cohort consisted of 4647 full-time civilian employees who worked between April 1973 and December 1985. All of these civilian workers resided off-base where there was no known contamination. The individuals worked in maintenance facilities, administrative offices, commissaries, and warehouses in the main area of the camp, which was served by the Hadnot Point water system. The comparison cohort at Camp Pendleton, California, included 4690 full-time civilian employees. In this analysis, the elevated mortality from all cancers was not as evident as in the previous study (HR 1.12, 95% CI 0.92–1.36). An exposure–response relationship was found with higher levels of chloride and PCE associated with increased leukemia-specific mortality. Among the diseases of primary interest, the HR for mortality was elevated for kidney cancer (HR 1.92, 95% CI 0.58–6.34), multiple myeloma (HR 1.84, 95% CI 0.43–7.58), and leukemia (HR 1.59, 95% CI 0.66–3.84). When the result was viewed together with the previous study on the cohort of Marine and Naval personnel, the cancers with elevated mortality in both studies were kidney cancer, multiple myeloma, leukemia, rectal cancer, lung cancer, and prostate cancer [ 41 ]. One potential confounder in both studies was the effect of other carcinogens. Although individual information on smoking and alcohol use was unavailable, comparing the two cohorts of similar demographics and occupations in Camp Lejeune and Camp Pendleton probably mitigated this confounding effect. The 95% CIs were wide in these studies because of the small numbers of deaths that occurred. The median age at the end of follow-up was 49 years among the Marine and Navy personnel, and 58 years among the civilians, which could be too young to sufficiently monitor cancer occurrence, let alone cancer-specific mortality.

In addition, there was a case report of hairy cell leukemia in a 55-year-old man who served at Camp Lejeune for 5 years in the 1970s [ 42 ]. Although this report does not establish a definite causal link between water contamination and hairy cell leukemia, the patient did not have any other known exposure to pesticides, petroleum, or radiation. The estimated incidence of hairy cell leukemia is three cases per one million person-year in the United States [ 43 ].

Discussion and conclusions

Janey Ensminger, a daughter of a former Marine Corps Master Sergeant, Jerry Ensminger, was born in 1976 when her family was living at Camp Lejeune. In 1983, Janey was diagnosed with acute lymphoblastic leukemia, and in 1985, she died at the age of 9. Since then, Jerry, her father, struggled with reconciling himself to her death in light of no family history of the disease. A plausible explanation was not found until 1997 when he discovered in the local news that the tap water at Camp Lejeune was contaminated by toxic chemicals for nearly three decades. Since then, Jerry Ensminger has campaigned for the potential victims among former Camp Lejeune residents, seeking to establish a medical health registry and provide due benefits [ 44 ]. In 2012, Congress passed the Honoring America’s Veterans and Caring for Camp Lejeune Families Act, which covers medical care for veterans and family members affected by the water contamination. In response, the Institute of Medicine (IOM) published a VA clinical guidance for health conditions identified among the potential victims. To be eligible for benefits under the law, a veteran or family member must have resided at Camp Lejeune for at least 30 days between January 1, 1957, and December 31, 1987. Latency period was not considered, to maximize benefits for the veterans and families. Cancers or neoplasms that are covered under this act are esophageal cancer, lung cancer, breast cancer, bladder cancer, kidney cancer, leukemia, multiple myeloma, non-Hodgkin’s lymphoma, and myelodysplastic syndrome. Precancerous lesions are also listed, including ductal carcinoma in situ of the breast, Barrett’s esophagus, and monoclonal gammopathy of undetermined significance. Cancers that have been diagnosed any time during or after residency at Camp Lejeune are included, and clinically indicated screening is also covered without a co-pay for veterans and their families [ 45 ].

Initially, it seemed more than coincidental that three patients who were affected by the water contamination at Camp Lejeune were seen in one clinic located 1000 miles away. On the other hand, the encounter with these three patients speaks to the magnitude of the contamination and the numbers of patients spread throughout the United States and abroad. Based on our experience, it is likely that people who have lived in Camp Lejeune will be seen in oncology clinics across the country with a new cancer diagnosis. For those affected individuals, thorough history-taking can lead to a high level of vigilance and appropriate cancer screening, so that the eligible patients may receive financial coverage for the medical care that they need. We hope that this article raises awareness about the history of Camp Lejeune’s water contamination among cancer care providers and ultimately serves as a public reminder about the importance of chemical carcinogens in the surrounding environment.

Availability of data and materials

All data supporting the findings of this study are available within the published article and its Additional file 1 .

Abbreviations

Perchloroethylene

Trichloroethylene

Dichloroethylene

Maximum contaminant level

Environmental Protection Agency

North Carolina Department of Natural Resources and Community Development

Volatile organic compound

US Geological Survey

Complete blood count

White blood cell

Central nervous system

Acute lymphoblastic leukemia

Next-generation sequencing

Measurable residual disease

Prostate-specific antigen

Stereotactic body radiation therapy

Chronic lymphocytic leukemia

Agency for Toxic Substances and Disease Registry

Hazardous Substance Release and Health Effects Database

Confidence interval

Standardized incidence ratio

Trihalomethanes

Trichloroethane

World Health Organization

International Agency for Research on Cancer

Maximum contaminant level goal

Standardized mortality ratio

National Cancer Institute

Hazard ratio

Institute of Medicine

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Acknowledgments

We thank Morris L. Maslia, PE, D.WRE, DEE (M. L. Maslia Consulting Engineer) for providing the map of Camp Lejeune used in Fig. 1 .

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Classification of carcinogens by the IARC. Table S2. Hierarchical categories of carcinogens by EPA.

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Jung, K., Khan, A., Mocharnuk, R. et al. Clinical encounter with three cancer patients affected by groundwater contamination at Camp Lejeune: a case series and review of the literature. J Med Case Reports 16 , 272 (2022). https://doi.org/10.1186/s13256-022-03501-9

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6.5 Case Study: The Love Canal Disaster

One of the most famous and important examples of groundwater pollution in the U.S. is the Love Canal tragedy in Niagara Falls, New York. It is important because the pollution disaster at Love Canal, along with similar pollution calamities at that time (Times Beach, Missouri and Valley of Drums, Kentucky), helped to create  Superfund , a federal program instituted in 1980 and designed to identify and clean up the worst of the hazardous chemical waste sites in the U.S.

Love Canal is a neighborhood in Niagara Falls named after a large ditch (approximately 15 m wide, 3–12 m deep, and 1600 m long) that was dug in the 1890s for hydroelectric power. The ditch was abandoned before it actually generated any power and went mostly unused for decades, except for swimming by local residents. In the 1920s Niagara Falls began dumping urban waste into Love Canal, and in the 1940s the U.S. Army dumped waste from World War II there, including waste from the frantic effort to build a nuclear bomb. Hooker Chemical purchased the land in 1942 and lined it with clay. Then, the company put into Love Canal an estimated 21,000 tons of hazardous chemical waste, including the carcinogens benzene, dioxin, and PCBs in large metal barrels and covered them with more clay. In 1953, Hooker sold the land to the Niagara Falls school board for $1, and included a clause in the sales contract that both described the land use (filled with chemical waste) and absolved them from any future damage claims from the buried waste. The school board promptly built a public school on the site and sold the surrounding land for a housing project that built 200 or so homes along the canal banks and another 1,000 in the neighborhood (Figure 1). During construction, the canal’s clay cap and walls were breached, damaging some of the metal barrels.

Eventually, the chemical waste seeped into people’s basements, and the metal barrels worked their way to the surface. Trees and gardens began to die; bicycle tires and the rubber soles of children’s shoes disintegrated in noxious puddles. From the 1950s to the late 1970s, residents repeatedly complained of strange odors and substances that surfaced in their yards. City officials investigated the area, but did not act to solve the problem. Local residents allegedly experienced major health problems including high rates of miscarriages, birth defects, and chromosome damage, but studies by the New York State Health Department disputed that. Finally, in 1978 President Carter declared a state of emergency at Love Canal, making it the first human-caused environmental problem to be designated that way. The Love Canal incident became a symbol of improperly stored chemical waste. Clean up of Love Canal, which was funded by Superfund and completely finished in 2004, involved removing contaminated soil, installing drainage pipes to capture contaminated groundwater for treatment, and covering it with clay and plastic. In 1995, Occidental Chemical (the modern name for Hooker Chemical) paid $102 million to Superfund for cleanup and $27 million to Federal Emergency Management Association for the relocation of more than 1,000 families. New York State paid $98 million to EPA and the US government paid $8 million for pollution by the Army. The total clean up cost was estimated to be $275 million.

The Love Canal tragedy helped to create Superfund, which has analyzed tens of thousands of hazardous waste sites in the U.S. and cleaned up hundreds of the worst ones. Nevertheless, over 1,000 major hazardous waste sites with a significant risk to human health or the environment are still in the process of being cleaned.

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Case studies in groundwater contaminant fate and transport

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A case study of groundwater contamination is a detailed study of a single site contaminated with a chemical or mixture that is known to be a problem at many sites. The goal of case studies is to provide insights into the physical, chemical, and biological processes controlling migration, natural attenuation, or remediation of common groundwater contaminants. Ideally, processes occurring at a case study site are representative of other sites so that knowledge gained from these intensive studies can be applied at thousands of sites where fewer data are available. Several characteristics of case studies contribute to their value. First, they may have tens to hundreds of monitoring wells, compared to fewer than ten wells at some contaminated sites. Second, some case studies continue for many years or even decades, providing insights into temporal progression of slow processes. Third, analytical methods prohibitively expensive for routine use or under development may be tested at case study sites. Finally, the ongoing characterization typical of case study sites builds a foundation of knowledge that facilitates sophisticated experimental design and testing of new methods. This article is divided into sections based on the contaminant type because the chemical and biological processes required for remediation vary for each contaminant. Most importantly, some contaminants can be biodegraded whereas metals and radionuclides cannot be destroyed but can be immobilized or rendered less toxic. The emphasis is on case studies of natural processes that control the fate and transport of contaminants in groundwater rather than on active remediation methods. The principles learned from these studies may form the basis for design of remedial strategies. The organic contaminants are divided into: petroleum hydrocarbons, fuel oxygenates, coal tar and wastes from manufactured gas plants, and chlorinated solvents. The inorganic contaminants covered are metals and radionuclides, arsenic, and nitrate. Case studies of mixed waste plumes from landfills are also described. Experimental sites where contaminants have been introduced into an aquifer as an emplaced source or a controlled release may not meet the above definition of case studies, but some are included because the overall goal is to impart lessons learned from detailed field studies. It is impossible to cover all case studies in this short format. Conversely, focusing on one or two does not convey the breadth of research results in entire range of case studies. Instead, the strategy is to describe the evolution of knowledge for each contaminant class while providing citations of relevant case studies. Much of the progress in understanding of the fate of contaminants in groundwater is based on laboratory studies; thus whenever possible, papers that included both field and laboratory results have been included among the citations. Two topics of growing importance have not been covered. These are the fate of pharmaceuticals in groundwater and discharge of contaminant plumes to surface water. These topics merit coverage in the future as knowledge grows and case studies increase in number.

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Environmental Methamphetamine Exposures and Health Effects in 25 Case Studies

Jackie wright.

1 College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide 5001, Australia; [email protected] (K.R.); [email protected] (S.W.)

2 Environmental Risk Sciences Pty Ltd., P.O. Box 2537, Carlingford Court 2118, Australia

Michaela Kenneally

3 Forensic Science SA, GPO Box 2790, Adelaide 5001, Australia; [email protected]

Kirstin Ross

Stewart walker.

The clandestine manufacture and use of methamphetamine can result in contamination of residential properties. It is understood that this contamination remains in homes for a significant period, however there are a lack of data available to understand the health effects of exposure to environmental methamphetamine contamination (third-hand exposure). Our study collected information from 63 individuals in 25 separate case studies where the subjects had unwittingly suffered third-hand exposure to methamphetamine from former manufacture, use, or both. Data included environmental contamination data, information on subjects’ health effects, and evidence of exposure using hair analysis. This study identified a range of health effects that occur from residing in these properties, including behavioural effects or issues, sleep issues, respiratory effects, skin and eye effects, and headaches. Methamphetamine was detected in hair samples from some individuals, including children. The exposures and concomitant reported health effects covered a wide range of environmental methamphetamine levels in the properties, including low levels close to the current Australian guideline of 0.5 µg methamphetamine/100 cm 2 . There were no discernible differences between health effects from living in properties contaminated from former manufacture or use. This study demonstrates that residing in these properties can represent a serious public health risk.

1. Introduction

Unlike the controlled manufacture of drugs, the clandestine manufacture of methamphetamine results in the uncontrolled storage, use, generation, and disposal of a wide range of chemicals, as well as the deposition of methamphetamine drug residues on indoor surfaces [ 1 ]. Further, the smoking of methamphetamine results in the deposition of residues onto the surfaces of properties where the activity is undertaken [ 2 , 3 ]. These residues have been found at varying levels on a wide range of household surfaces and materials, and have been shown to persist for months or even years [ 1 , 4 , 5 , 6 ]. People working or living in these contaminated properties are exposed to these methamphetamine residues. At present, there is limited information available in relation to these exposures and the health effects that occur as a result [ 7 , 8 ].

The operation of clandestine methamphetamine laboratories results in the presence of a wide range of hazards and risks within the premises during and following manufacture [ 7 ]. The most significant adverse health effects are those derived from immediate acute hazards. These hazards include the uncontrolled and unprotected storage and use of chemical precursors that are volatile, flammable, or reactive; and the release of high concentrations of toxic gases (that may include ammonia or phosphine) into a room or home where ventilation is limited and where there is the potential for unprotected exposures. Data are available [ 9 , 10 , 11 , 12 , 13 , 14 ] that show that a range of individuals, including children, in clandestine drug laboratories are at high risk of injury and illness associated with immediate hazards such as fires, explosions, and chemical incidents, as well as acute and chronic exposure to the range of chemicals used to manufacture the drugs and the drugs themselves. There is also a significant body of research related to the health effects of methamphetamine use, including the effects of exposure of children to methamphetamine in utero [ 15 , 16 , 17 ].

However, once manufacture and use has ceased and the acute hazards associated with manufacture are no longer present, methamphetamine contamination remains at the property. If this contamination is not remediated it can remain for a long period of time [ 6 ], resulting in long-term or chronic environmental (also known as third-hand) exposure to people living or working in these properties. The evidence suggests that the level of methamphetamine manufacture and use in Australia is increasing. It is estimated that police only detect 1 in every 10 drug laboratories [ 18 , 19 ]. Guidance is available in Australia for the assessment and remediation of former clandestine drug laboratories, however there are a large number of properties contaminated as a result of manufacture and use where the presence of contamination is unknown [ 3 ], and there are no regulatory requirements for the testing and remediation of these properties. Hence, in most situations, exposure to methamphetamine residues in properties purchased or rented by the public is unknown.

It is commonly assumed that third-hand exposure to drugs such as methamphetamine is low compared with exposure related to illicit drug use, exposures during manufacture, or legal therapeutic use of amphetamine-based drugs, with the likelihood of adverse health effects assumed to be negligible. This assumption is principally due to the lack of data available on the health effects of environmental methamphetamine exposures.

This study has been undertaken to characterise and better understand exposures and health effects associated with unwitting environmental exposures to methamphetamine residues in residential properties.

2. Materials and Methods

2.1. general.

The focus of this study related to characterising exposures and health effects in individuals who have had unwitting environmental exposures to methamphetamine contamination as a result of residing in place of former manufacture or use. These individuals are difficult to identify, as the activities and behaviours that result in the presence of methamphetamine contamination in properties are illegal, and therefore are unknown to those purchasing or renting a property. As a result, the information and data that can be obtained in relation to these exposures is derived from opportunistic case studies.

The case studies presented in this research were obtained over the period 2013 to 2019 and provide varying amounts of concomitant data on exposure, characterised on the basis of environmental contamination levels, biological data, health effects, and interview data. As the case studies are opportunistic, the information and data obtained relate to varying time periods and exposure situations.

All individuals gave their informed consent for inclusion prior to participation in the study. Ethics approval for all case studies included in this research, to collect information on environmental contamination levels, to conduct interviews, to evaluate behavioural issues in children using the Behavior Assessment System for Children (BASC), Parent Rating Scheme (PRS) as BASC-2:PRS and BASC-3:PRS [ 20 , 21 ], and to obtain hair samples, where relevant, was obtained from the Southern Adelaide Clinical Human Research Ethics Committee (Application 477.11, approved 15 March 2012 with extension approved 27 October 2015) and the Social and Behavioural Research Ethics Committee (SBREC) at Flinders University (Project No. 7902, approved 14 March 2018).

2.2. Identification of Opportunistic Case Studies

These case studies were identified through links with contamination assessment and remediation companies, legal firms, and real estate organisations who identified individuals and families living in methamphetamine-contaminated homes and recommended their participation in this study. Individuals identified from these opportunistic case studies were only included if these individuals had resided in properties formerly known or suspected to have been used for the manufacture or smoking of methamphetamine. Current users of methamphetamine and other amphetamine-type stimulants were identified on the basis of responses to questions on drug use and were not included in the study. Once identified, informed consent was obtained for all individuals who participated in this study.

2.3. Characterisation of Exposure

Potential exposures within each property were evaluated on the basis of two types of data: environmental contamination levels and hair analysis.

2.3.1. Environmental Contamination Levels

The presence of methamphetamine contamination in properties was characterised on the basis of surface wipe testing. These data are collected and are inferred to represent the mass of methamphetamine on different surfaces that may be accessible and available for participants to come into direct contact with, and where these residues may transfer onto the skin and other objects and ingested or dermally absorbed. Data relating to the nature and extent of methamphetamine contamination in each property was provided by the property owner or tenant, as the result of environmental testing conducted by an independent testing company. Data provided for use in this study relates to individual wipe samples collected from each premises, and analysed by various accredited laboratories for methamphetamine, along with amphetamine, ephedrine and pseudoephedrine (in most cases). The data provided have been reviewed to ensure compliance with NIOSH guidance in relation to sampling [ 22 ].

2.3.2. Hair Analysis

Where participants had been exposed in a property for more than three months and participation in this study occurred during or just after the period of exposure occurred, hair samples were collected (under informed consent protocols) to provide an estimate of environmental intake or exposure.

The hair samples were collected using a hair sampling kit in accordance with the hair sampling procedure provided by Forensic Science SA, Adelaide, Australia. This procedure is consistent with the sample collection procedure detailed in the Society of Hair Testing guidelines [ 23 ]. This involved giving the sample a unique identify code, using gloves, and cutting hair from the crown or vertex of the head as close to the scalp as possible using clean sharp scissors. Where possible, the hair sampled was approximately the thickness of a pencil. Where the hair was thin or short, hair was sampled from more than 1 location on the crown or vertex to maximise the amount of hair sampled. Each hair sample was contained in the supplied aluminium foil, ensuring that the cut end was aligned with the marking on the foil and that the foil wrapped around the hair sample. Each hair sample was then placed into a supplied envelope, which was sealed for chain of custody purposes, with the sample ID, date, and time of collection noted. The envelope and copy of the participant’s informed consent form were then placed into a sealable bag, which was then sealed. The samples were securely stored at room temperature prior to analysis. Information relating to hair colour and whether the hair was dyed was recorded.

The hair samples were analysed for methamphetamine and amphetamine by Forensic Science SA. The method involves extraction using methanol and analysis using liquid chromatography with tandem mass spectrometry (LC-MS/MS) using an electrospray ionisation (ESI) source.

Preparation and Extraction: An approximately 3 cm segment of hair was cut into segments of 1–5 mm in length, then 20 mg transferred into a glass tube. Any environmental (external) contamination of the sample was removed by a brief (approximately 30 s) wash with 2 mL methanol. The methanol wash was analysed separately. An internal standard (d 5 -methylamphetamine for methylamphetamine or d 5 -amphetamine for amphetamine) was added and extraction of the drugs from the sample was achieved by incubation overnight (approximately 18 h) at 45 °C in 2 mL methanol. Following extraction, the sample was allowed to cool to room temperature and the methanol was transferred via pipette to a disposable test tube. Acid alcohol (20 µL of 0.5% hydrochloric acid in methanol) was added to form the hydrochloride salt of the amphetamines prior to solvent evaporation under a steady stream of nitrogen at 40 °C. This ensures that amphetamines are not lost in the evaporation stage. The residue was reconstituted with 100 µL of 0.1% formic acid to match the mobile phase and ensure satisfactory chromatographic peak shapes and separation. The samples were transferred to a 2 mL vial then capped and centrifuged for 5 min prior to analysis.

Analysis: The extract was analysed by LC-MS/MS using an ESI source, as described above. The instrument used was an Agilent 1200 LC system with Applied Biosystems 4000Q-Trap MS. The column was a Phenomenex Luna PFP(2) 3 µm 50 × 4.6 mm with a pentafluorophenyl (PFP) guard column measuring 5 µm 4 × 2.0 mm. Deuterated analogues of the drugs were used as internal standards. A blank and quality control samples (purchased commercial external hair controls and a previous drug-positive proficiency case sample) were included with each batch run. Calibration curves were constructed and used to calculate the drug concentrations in the samples.

The sensitivity of the instruments enables the identification and quantification of trace levels of drugs, with a quantitation limit of 5 pg drug per mg hair (pg/mg) for amphetamines. While it is common for the reporting of drugs in hair to include a reporting limit (to remove low level detections that may be the result of prescribed medications or low level instrument error), the analysis undertaken for this study included all trace level detections, as none of the participants were drug users.

2.4. Characterisation of Health Effects

2.4.1. interview data.

Participants in the study were interviewed. Where children were involved, information was provided by the parent or caregiver. Each participant was given a unique ID, which was used for all information relating to the participant, including the hair analysis (where relevant). The interview involved a number of questions that related to the following:

• Participants—age, gender, hair colour, whether the hair was dyed, use of amphetamine-type stimulants, including attention-deficit/hyperactivity disorder (ADHD) drugs (particularly relevant for children);
• Housing situation—owning or renting, duration of time at the property, how much time is spent in the property, including whether the participant was the primary cleaner in the home, if they had undertaken renovations in the home, or whether children undertake a lot of floor play;
• Exposure situation—how the participant or family came to be living in the property and how they found out that the property was contaminated. Information about whether the property may have been contaminated from manufacture or use was also obtained;
• Health information—identification of pre-existing conditions, description of health issues that occurred while living in the property, with medical records or school attendance plus medical records provided to support the information provided, and information on whether the health effects persisted when out of the property. Where the health problems had resolved, questions relating to how long the health effects persisted after moving out of the home were also included. The collection of health information focused on health effects that occurred within the property that were different from or worse than health issues experienced prior to living in the property. As the health effects being documented were self-reported, it was considered important to document health effects specifically related to the time spent in the property. For some case studies, children had spent their whole lives living at the contaminated property. For these participants, the health information obtained from parents related to their overall health. In some cases, health effects related to the property could be identified more clearly as these did not persist whenever the participant was out of the property.

2.4.2. Behavioural Assessment

For children involved in the study, a behavioural assessment was completed by the parent or caregiver using the Behaviour Assessment System for Children Second Edition (BASC-2) and Third Edition (BASC-3) [ 20 , 21 ] forms for each child. BASC-2/BASC-3 are standardised assessment tools that provide information to assist in assessing a child’s behavioural, emotional, and adaptive functioning. The tools can be used with children aged from 2 years to adolescents aged 21 years. There are a range of forms and scales available. For the purpose of this assessment, the Parent Rating Scales (PRS) were used. The PRS forms used related to the ages of the children residing at the premises, i.e., aged between 2 and 5 years, between 6 and 11 years, or 12 to 21 years. The scales use four choices for responses to each of the questions asked: never, sometimes, often, and almost always.

Once completed by the parent or caregiver, the BASC-2/BASC-3 forms were scored using the Pearson online scoring system. The online scoring includes a check for the validity of responses and scoring against normalised groups, with the general combined-gender norm group used for the scoring in this study.

3.1. Opportunistic Case Studies

Twenty-five opportunistic case studies were identified and included in this study between 2013 and 2019. As these case studies were opportunistic, each case study was different, particularly in relation to the housing and exposure situations. The following provides a brief summary of the exposure situation relevant to each of the case studies, specifically the individual situations, along with unique characteristics and issues related to each property.

CS01: This case study related to a rural property. Police had seized chemicals and manufacturing equipment from the property and notified the local council of the seizure. The owner of the property at that time was arrested and charged. The local council issued a notice to the owner requiring assessment and remediation, however the notice was not acted on and was not followed up by the council. The property was subsequently sold to a family with 2 adults and 3 children. The new owners were notified by the local council approximately 8 months after moving in that the property was formerly used to manufacture methamphetamine and there was an outstanding notice. The local council undertook an assessment of contamination that took another 10 months, after which time it was clear that the property was contaminated and the family moved out, leaving all possessions behind. The family lived in the contaminated property for approximately 18 months. In relation to this case study, additional testing of the property has been undertaken by the researcher over a number of years, in addition to the data provided by the local council [ 6 ].

CS02: This case study related to a rental property in an urban area occupied by a mother and 2 children. At the time of signing the rental agreement, there was no information provided that indicated that the owner of the property had been arrested for the manufacture of methamphetamine. Management of the property was undertaken by the owner’s mother. At the time of rental, the owner’s mother, sister, and letting agent (a friend of the sister) were aware that the property had formerly been used to manufacture methamphetamine, but the tenant was not informed. The owner cleaned the property and replaced curtains prior to letting. Neither the police nor the local council had knowledge of the property in relation to the manufacture of methamphetamine. The tenant became aware of potential methamphetamine contamination as a result of conversations with neighbours, who told them about the former tenant, who received a prison term for methamphetamine manufacture. The tenant was also suspicious of contamination as the tenant’s son’s behaviour was significantly different when living at home compared with times when he spent at least a week out of the home. The tenant had the property tested. Once contamination was discovered and was found to be higher in the lower level (basement) where the tenant’s son resided, the family moved out without their possessions. The local council was notified of the results and they issued a clean-up notice to the owner.

CS03: This case study related to the purchase of a home in an urban area, which was occupied by a single adult. The home was not known to have been formerly used for the manufacture of methamphetamine at the time of purchase, as there was no notification on any searches undertaken during the sale of the property. When the property was purchased, the owner started renovation works and became unwell very soon after commencing these works. The owner became concerned about the property when she saw a newspaper article about police seizing manufacturing equipment and arresting the occupant of another property. She recognised the arrested individual as the former occupant of her property. The owner also notified the local council and was informed that the council was aware the home was formerly used to manufacture methamphetamine, but this information was not provided at the time of property sale. There was also information that the property had some level of remediation (details unknown), however testing after renovations were undertaken indicated that the property had been re-contaminated as a result of renovations.

CS04: This case study involved a short-term private rental of an urban property by a family with 2 adults and 2 young children. Within days of moving into the property the neighbours told them the previous tenant had been involved in manufacturing methamphetamine in another house across the road and was currently involved in court proceedings. The neighbours did not know whether their home had been used to manufacture methamphetamine or whether the tenant had only used methamphetamine in the house. The tenant contacted the owner, who refuted the claim of manufacture and stated the house had been professional cleaned prior to occupancy. In addition, the tenant bleached the walls on moving in. The children were unwell whenever spending time in the house, so the tenants organised to get the property tested. The property was found to be contaminated and the tenants moved out.

CS05: This case study involved the rental of an urban public housing property with a known drug use history by 2 adults and 1 child. The property was initially tenanted by the family’s mother who had a history of drug use, including heavy use (primarily smoking) of methamphetamines. During her time living at the property (more than 10 years), she took in a number of boarders, some of whom were also drug users. The property was affected by methamphetamine contamination primarily as a result of the long-term smoking of the drug. However, there was a suspicion that the property may have also been used for the manufacture of methamphetamine by boarders staying at the property. After moving into the home, all occupants experienced health problems. After suspicions about contamination were raised, the property owner tested the property and determined it was not suitable for occupancy. The family were told to leave the property by the public housing authority, leaving all their personal property in the house.

CS06: This case study involved the rental of an urban public housing property by a single adult for a period of 7 years. Within a few weeks of moving into the home the occupant experienced a range of health problems, which persisted when she was in the home. She became suspicious of the presence of contamination in the home after becoming aware that exposure to methamphetamine contamination can result in similar health effects as being experienced. The property was tested for contamination and found to have levels in excess of the relevant guideline. The tenant vacated the property once the results were received by the owner. When the occupant originally moved in, she noted the presence of drug bags and needles hidden in cupboards and under rugs and loose floor tiles, and people would often approach the house looking to buy drugs. There was no evidence or suspicion of manufacture. This suggested the property had a prior history of drug use (and potentially supply) but not manufacture. It is noted that the property is located directly adjacent to a major motorway where elevated levels of noise and vehicle exhaust fumes are also noted to be an issue. The tenant had significant levels of stress during and after discovering the property was contaminated due to the way in which the issue was handled. Some of the health effects were resolved on moving out, however a number of health effects have remained unchanged for years, in particular eye damage and chronic fatigue.

CS07: This case study involved the rental of an urban home by an adult and one child for a period of 2 years. While living in the home, the daughter’s behaviour changed significantly and the cause could not be identified by her family doctor or from teachers from her school (who had also noted the changes in behaviour). Discussions with neighbours about these problems identified that the previous tenants had a history of drug use and drug dealing behaviour. The landlord had to do a number of repairs to the home before renting it out again, however no assessment or remediation of contamination was undertaken. Subsequent testing of the property identified the presence of methamphetamine contamination, after which time the tenants vacated the property.

CS08: This case study involved a house on the urban outskirts of a major city that was purchased by a family of 2 adults and 3 children. The property was vacant for a number of months prior to the sale. During the sale of the property, access into the property was restricted and the purchasers were advised to change the locks once moved in for their safety. Information from some of the neighbours indicated that the previous occupants used methamphetamine and there was also some suggestion of drug manufacture. Other neighbours refuted the manufacture but confirmed that the previous owners used drugs in the property. Discussions with police did not identify any drug-related reports. After the family moved in, they started renovations, and given the potential drug history at the property they became concerned about contamination and had the property tested. They had noticed some health issues and sleep issues with one of their children. The testing showed the property was contaminated. They lived in the property for 4 months prior to discovering it was contaminated. They could not afford to move out so lived in a caravan on the property until the remediation was completed.

CS09: This case study involved the rental of an urban unit by 2 adults for a period of approximately 5 months. Following concern about the condition of the property being rented, contamination testing was undertaken, which identified the presence of methamphetamine contamination. The tenants were issued with an order to vacate from the owner, citing the property was unsafe for occupancy. The couple renting the property left without their possessions. No health effects were reported by the couple living in the property, however they were expecting a baby and were very concerned about the health of their unborn child, as well as the condition their property would be returned in after remediation (which was proposed). They did not want to have any possessions returned that had any potential for methamphetamine to be present, as many of the items were new baby items. This couple had to take legal action to recover some costs associated with possessions that had to be destroyed. After moving out the couple had a healthy baby.

CS10: This case study involved the rental of a unit in a rural town by a single adult for 3 years. While not a public housing unit, the property was from a charity rental group. The occupant was a victim of domestic violence and needed urgent accommodation, so the property was rented sight unseen. The property was in poor condition and a neighbour indicated that the unit had been used to cook methamphetamine. The occupant became unwell, although she was not aware that exposure to contamination from former methamphetamine cooking could cause health issues until she saw a media article on the issue. Some of the health issues experienced related to mood, anxiety, and depression, and at times she thought she was going mad and attempted suicide. She asked the landlord about the presence of contamination, who initially offered to pay her and fix the outstanding repairs on the property, however this was not accepted, and the landlord ultimately tested the property. The property was found to be contaminated and the occupant moved out without any possessions. Many of the health effects were resolved when the tenant moved out of the property.

CS11: This case study involved the rental of a home by a single adult in a large country town for approximately 7 months. The occupant’s previous rental property had been sold and she was given 30 days to vacate. She had pets, meaning rental options were limited, and this was the only property that would allow pets, so she felt she had no choice with the property. She cleaned the home on moving in but felt unwell whenever in the home. The real estate agent she was dealing with had started testing some rental properties for methamphetamine, so she requested that her property be tested given how unwell she had been. The testing confirmed that the property and her possessions were contaminated and she had to move out, leaving her property behind. The source of contamination (manufacture or use) is not known. The issue had to go through a tenancy tribunal to sort out personal property and get compensation for property that had to be destroyed.

CS12: This case related to the rental of an urban house by a family of 2 adults and 3 children for approximately 4.5 months. The family moved from a rural area to a major city due to a change in employment and rented a property. When they moved into the property, they found a syringe. Neighbours indicated that the previous tenant had 2 large guard dogs and there was often unusual activity at night. The children were noticeably unwell and behaved differently within the house. With this information and awareness of the potential for methamphetamine contamination to be of concern, the tenants had their property tested. The testing showed that the property was contaminated and they moved out of the home, leaving their possessions behind. It is not known whether the contamination was the result of manufacture or use.

CS13: This case study involved exposure by an adult with diagnosed multiple chemical sensitivity to contamination in an urban home. The participant had been living in community housing for the past 20 years and was required to move due to the need for major renovations. He moved into a new community housing property that was observed to be very rundown. Every time he visited the property for short periods of time (up to 40 min duration) while taking possessions to the property, he felt unwell. This only occurred when entering the home, even for short periods of time, with the effects lasting after exiting the property for up to a few days. The adverse health effects tended to become continuous with repeated entry into the home. He was suspicious of past activities in the home, believed to be heavy drug use, based on discussions with neighbours. Awareness of potential methamphetamine contamination prompted him to get the property tested. This identified that the property was contaminated. He never completed moving in, however he had to deal with his possessions that had already been moved in and were found to be contaminated.

CS14: This case study involved exposure of a young child to residues in the mother’s home in an urban area during visitation over a period of just over 2 years. The mother and father were separated and the child was spending equal time between the mother and father. The mother was known to be using methamphetamine in the home when the child was not present. The father was on a methadone program. The father was concerned about the child being exposed to methamphetamine in the home whenever he was residing with the mother. He noticed that the health and behaviour of the child was different or poor whenever the child had spent time at the mother’s property. Testing of the child’s hair identified trace levels or methamphetamine. The presence of methamphetamine in the child’s hair was of concern to the mother and father, and resulted in the mother ceasing methamphetamine use and moving out of the contaminated property. The child’s health has improved significantly.

CS15: This case study involved a mother and child renting an urban community housing unit for approximately 3 years. The family had been living in community housing for a while and transferred to this property following a domestic violence incident. When moving into the unit she noticed that both she and her son’s health were impaired, and initially thought it may be the result of exposure to mould. Discussions with neighbours indicated that the police had arrested the previous tenant (6 months prior to her moving in) on drug-related charges (specifics unknown). The housing authority did not inform her of the previous drug and police history. After thoroughly cleaning the house, heightened awareness through media reports of the potential presence of methamphetamine contamination made her suspicious. Her son’s health was problematic, with significant asthma and constant respiratory infections resulting in him missing a lot of school. This, in turn, made it difficult for the mother to secure employment. She had the property tested, and while methamphetamine was detected, it was not above the relevant guideline. She insisted that the properly be remediated to remove the methamphetamine contamination. The property was remediated, and both her and her son’s health have improved since remediation was completed. The family remains living in the property.

CS16: This case study involved the rental of an urban unit by a single female adult with previously diagnosed multiple chemical sensitivity. She was previously living in a property that was contaminated with mould that made her unwell. She had to move out of that property and leave most of her possessions behind due to the effect it was having on her health. She moved into a different unit that was clean as a short-term rental in order to help her recover from the effects of living in the mould-affected home. A more permanent rental unit became available in the same building and she was told it was the same as the unit she was in and was also clean. She moved out of the short-stay and into the rental property. When she moved into the property, she became unwell again. She experienced a wide range of significant health problems in the unit. She became suspicious of drug activities in the building and in her unit based on the dirt and dust, noting strange smells and items found in the unit (e.g., a bag of pseudoephedrine under tiles on deck). She suspected another unit close to hers was being used for manufacture. As her health declined, her partner had to leave his job to become a fulltime carer. She contacted police with her suspicions of manufacture. She had the property tested for methamphetamine contamination and elevated levels were found. She moved out, leaving her possessions behind. Initially she had to live in her car as she had no money for alternate accommodation. Her health improved over time, taking around 6 months for most of the effects to be resolved.

CS17: This case study involved the rental of a home in a suburban area by a single male adult for a period of approximately 5 months. The property was rented through a rental agency, with no issues identified. The property was clean and tidy. Not long after moving in, a car arrived and the occupants informed him that the property had a drug history. Further discussions with neighbours also indicated that the property had a drug history. Enquiries with the property manager indicated that they knew the previous tenants were methamphetamine users. The real estate agency stated that they were only aware of methamphetamine use and no manufacture was suspected. However, manufacture could not be precluded. Subsequent enquiries with the agent indicated that the agent had previously found a knife taped to the back door, and during a previous inspection they found a table full of drugs and paraphernalia in the garage. On further inspection, the tenant found a packet of red powder hidden in the roof space and the property had a number of unusual water connections in the bathroom, laundry, and kitchen. There were also indications that the windows and some doors had been previously screwed or bolted shut. The tenant worked from home and became generally unwell. The property was tested for methamphetamine contamination, was found to be contaminated, and he moved out of the property without his personal possessions.

CS18: This case study involved the rental of a suburban home by a family of 2 adults and 2 children for a period of approximately 8 months. The family had moved from another city and the availability of rental properties was limited. They rented the property without an inspection, but were told by the estate agency that the property was clean and tidy, which was found not to be the case. The property was in poor condition and messy when they moved in. After they had moved in a sacked staff member from the real estate agency approached them and told them the previous tenant at their rental property was evicted for methamphetamine manufacture, and that the estate agency knew this was the case at the time the property was rented. No cleaning or remediation had been undertaken on the property. All members of the family were unwell in the property, with the mother and younger son more significantly affected. In particular, the mother was hospitalised three times due to severe headaches. Once the tenants were aware of the former drug history of the property, they had the property tested and it was found to be contaminated. They moved out without their possessions.

CS19: This case study involved a family of 2 adults and 2 children who purchased a suburban residential home 8 years ago and subsequently discovered it was contaminated with methamphetamine. Both their children were born while living at the property. Shortly after they had moved into the property, a neighbour told them the property had a drug history, however they dismissed this as unsubstantiated. The property had been well maintained and cleaned over the years. In addition, much of the property had been renovated and painted. Recent awareness of the potential presence of methamphetamine contamination from manufacture or use prompted the family to get the property tested. The initial sampling identified the property was contaminated and they moved out. The family found a newspaper article published about their home prior to their purchase of the home that indicated it was busted by police as a clandestine drug laboratory. The initial testing focused on timber that had not been painted or renovated, although this was not in areas that the family would come into contact with regularly. Further testing of surfaces that the family regularly touched, which had been repainted or were composed of new materials from renovations, was undertaken and little to no contamination was found. This case study did not find that the methamphetamine contamination was mobile or transferable within the property, which differs from many other properties presented here and may be due to the nature of the building materials in the home.

CS20: This case study involved the purchase of a rural property by a couple as a place for retirement. Renovations were being undertaken and the owners stayed in the property for only a few days at a time over a period of approximately 2 years. The property was purchased from a deceased estate. The previous owners had built the home, which was very well presented and clean. The new owners undertook a number of renovations, including painting. Once these works were complete, they spent more time at the home. When they had purchased the house, they asked the real estate agent about any former drug history and were told there was no history. Once they moved in, neighbours informed them that the previous owners were troublesome and involved with drug activities (potentially dealing), and the property was found to have been known to police. Both owners had a number of unexplained health effects since taking possession of the property, in particular the adult male. Once the property was known to be contaminated, they no longer entered the property without PPE. They organised to get the property tested and remediated. The initial testing focused on surfaces that were not renovated or painted by the owners. Further testing was then undertaken on all other surfaces in the property, including some areas where the paint was sanded back to identify levels of contamination beneath the freshly painted surface. This property had a significant number of samples collected from a range of surfaces and areas that the owners would come into direct contact.

CS21: This case study involved the rental of an urban residential home by a family of 2 adults and 1 teenage child for a period of approximately 4 weeks. The property owners indicated that the previous tenants had broken the lease. When vacated by the previous tenant, the property was very messy and required a lot of cleaning of the yard, kitchen, walls, doors, and windows, as well as repair and painting of the walls by the owner. The property had carpet cleaning undertaken, however stains remained on the carpet. The family rented the property, and not long after living in the home they noted an odour and were concerned that the odour may affect their health. This was initially assumed to be mould or damp from recent storms. An inspection was undertaken and there was no evidence of mould or damp indoors, however the inspection noted that the odour increased when windows and doors were shut and was “overwhelming” in rooms with carpet. The source of the odour was unknown and a mould treatment (fogging) was undertaken on the property. The odour remained and the tenants requested further testing, in particular for evidence of illicit drugs. A presumptive test was positive for methamphetamine and they moved out without their possessions prior to further testing being undertaken due to health issues, particularly for the son. Detailed testing was undertaken and the property was found to be contaminated with methamphetamine, assumed to be resulting from use. The tenants went to a tenancy tribunal to attempt to get compensation, however the state in which they reside only requires “clean” premises to be provided to tenants, and the tribunal interpretation of “clean” does not include contamination that is not visible, such as methamphetamine.

CS22: This case study involved the purchase of a suburban home approximately 11 years ago by 2 adults, who then rented the property out for 1 year prior to moving in, after which they discovered the home had been used to grow marijuana. The cleaning of the property for damage caused by hydroponics was covered by the landlord’s insurance. The family moved in and lived at the property for 10 years, with both of their children being born while living at the property. They conducted a number of significant renovations on the property. The children had never been without health problems while living at the property and the owners became suspicious that there might be other drug contamination present. They also discovered that police were aware that the tenant was a drug offender (specifics unknown). The owners had their property tested, which showed that the property was contaminated, so they moved out without their possessions. They regularly visit the property to let the kids play outside and sometimes enter the property. They undertook further testing of the property and possessions, all of which were found to be contaminated. The highest level of contamination was on the air conditioning unit. It is not known whether the property had been used for manufacture at the time when the hydroponics was grown, however the contamination levels that remain in the home are considered too high to be resulting from former use alone. The owners tried to get their insurance company to cover the costs of the methamphetamine contamination from the earlier tenant, however this has been unsuccessful. Since being out of the property the children’s health and behaviour have significantly improved.

CS23: This case study involved a family of 2 adults, 2 children, and their fulltime nanny, who lived in a family-owned suburban home. The father was found to be using methamphetamine over a number of years. The parents were in the process of separation at the time of this study, with the father having moved out of the home. The mother was concerned about the health of the children living in the property, with a number of behavioural issues observed in the children whenever living at the property. The property was tested and was found to be contaminated. Contamination was also found in the boot of the car, suggesting methamphetamine was used in the family car. The levels of contamination reported in the initial testing were found to be higher than would be expected for use alone, however there is no evidence or indication that manufacture ever occurred. The family moved out of the home, leaving possessions behind.

CS24: This case study involved the rental of a suburban home by a family of 2 adults and 3 children for approximately 6 weeks. When they moved into the property, they noticed that the property had been repainted (poorly) and there was a lot of rubbish and building rubble in the garden areas. One of their children, who had pre-existing asthma, was noticeably more unwell when in the home. Discussions with neighbours indicated that the previous tenants may have been using, dealing, or manufacturing drugs. Police were never involved with the property. Based on the suspicious of drug behaviour, they purchased a presumptive test, which returned a positive result. They then organised more detailed testing of the property, which found that the property was contaminated. The testing targeted locations in the home that were not recently painted. The family moved out once contamination was confirmed.

CS25: This case study involved the rental of a house through the public housing authority in a large township by a single older male for approximately 13 months. The first public housing home he rented was found to be located next to a methamphetamine laboratory, which was subsequently seized by police. While living at that property he had a number of issues with vapours and gases from the neighbouring property. After the police seized the laboratory, he was moved to a second rental property in the same town. He noticed an odour in the property and was unwell within days of moving in. Given his experience at the previous property he requested that the property be tested for methamphetamine contamination. Testing was undertaken in the home and it was found to be contaminated in a number of areas, including the bedroom and kitchen. He spent most of the day in the home and reported a number of health issues (including headaches that have required visits to the hospital). He noticed that the health issues resolved whenever he was away from the home for any period of time. He continues to reside in the property at the time of this study, as alternate accommodation is difficult to find.

The 25 case studies included in this study cover a broad range of properties and situations that resulted in exposure to methamphetamine contamination in the property. The duration of exposure in the properties varies significantly. Most had the opportunity to move out as soon as possible after discovering the presence of methamphetamine contamination, however there are some where it was not possible to move out of the home immediately. The broad range of properties outlined above is a snapshot of a complex issue that is often ignored or dismissed, as it has the potential to result in financial, emotional, and physical stress.

3.2. Property Details

Table 1 and Table 2 present a summary of the key characteristics of the properties and the contamination status of these properties from each of the case studies. The case studies included in this study are predominantly in urban or suburban areas (22/25 = 88%), most commonly detached houses rather than units (20/25 = 80%), and the majority were rented (18/25 = 72%) rather than owned (7/25 = 28%). Of the properties rented, 33% (6/18) were public or community housing. A wide range of exposure durations occurred, ranging from intermittent visits while moving in to 10 years living in the home. In total, 65 people (37 adults and 28 children) were included in the case studies.

Summary of key aspects associated with case studies.

R = Rural; U = Urban; H = House; A = Apartment or unit; O = Own; T = Tenant or rental; PH = Public housing (or similar).

Contamination status of properties included in case studies.

* Average level of contamination based on an arithmetic average of all samples collected, from all locations sampled in each property. It is noted that the sample locations differed for each property. Where contamination was reported as not detected, the analytical limit of reporting as stated by the laboratory was used. NA = data not available. For CS03, the available wipe sample results were provided as a minimum and maximum, and due to the historical nature of the contamination issues further testing was not possible. For CS14, the contamination status of the property was not available as access to the property was not possible.

All but one of the case studies relate to properties that were not seized by police as places of manufacture of methamphetamine. Of the properties, 8 (32%) were known or highly suspected to have been used for manufacture only, while 10 (40%) were known to have only been used for the smoking of methamphetamine. In 7 properties (28%), the source of contamination is not clear from the available information and may be from the manufacture or smoking of methamphetamine.

The level of methamphetamine contamination present in the home was characterised on the basis of surface wipe data (presented in Table 2 ). This information was collected on a property-by-property basis for the purpose of determining the presence of contamination, and in some cases informed remediation actions. As a result, the locations and types of surfaces sampled differed between homes. In addition, the data provided does not always represent surfaces that residents would only come into regular contact with. In some cases, the sampling of surfaces targeted areas where higher levels of contamination may be present, which often include surfaces that are not regularly touched. Such sampling protocols are likely to have biased the results (estimates might be higher than what would be found in more random sampling). Some case studies included a mix of surfaces, while others focused on the surfaces where higher levels were expected.

Exposure in a property may occur via direct contact, resulting in incidental ingestion of residues from hands and items, as well as dermal absorption [ 24 , 25 , 26 ]. The inhalation of methamphetamine present in dust and in the vapour phase is also expected to occur [ 1 , 27 ]. Hence, all data collected from all surfaces may contribute to the level of exposure. However, as the number of samples and surface types varied between each case study, the average residue level reported in Table 2 should only be considered as indicative.

3.3. Data from Individual Participants

From the 25 case studies included in this study, informed consent was obtained from all participants (63 in total), comprising 30 males and 33 females. Of these participants, 34 were adults aged 21 years and older, while 29 were children or adolescents, 22 of whom are aged under 12 years of age. A health survey was completed for all 63 participants, with hair samples collected and analysed from 36 participants. Behavioural assessment forms were completed for 18 of the 29 children and adolescents, all of which returned valid data for evaluation.

In relation to health effects, 6 participants did not report any health effects that specifically related to the time spent in the property. All other participants reported some health effects that were either unique to the time spent living in the property or were exacerbated by living in the property, regardless of the duration of exposure in the property. Of these participants, 67% provided doctors or school reports supporting the health effects or changes in health effects while residing in the property. Where health effects were identified for most participants, these resolved within weeks to months of moving out of the property. One participant, an adolescent, developed a more chronic liver issue that was unchanged after moving out.

The adverse health effects identified have been grouped based on common effects reported: skin irritation or rashes; eye irritation (sore or watering eyes); respiratory effects (persistent cough, asthma or asthma-like symptoms); immune effects (persistent and recurring respiratory infections); sleep issues (difficulty sleeping and unusual dreams); headaches; and behavioural effects (fatigue or tiredness; increased aggression or irritability; depression, anxiety or moodiness; vagueness or not thinking clearly; memory issues). The prevalence of these health effects for the participants included in this study is summarised in Table 3 .

Prevalence of health effects reported by study participants when exposed in contaminated properties.

Less commonly reported health effects included dental issues, particularly the delayed development of teeth in young children; speech delay in children; weight loss; appetite loss; loss of hair; having extra or excess energy; visual changes; dizziness and nausea; and increased blood pressure and tachycardia.

It is noted that two of the participants involved in this study reported health effects that were so severe that an ambulance was called or hospitalisation was required. This related to headaches in an adult and asthma in a child. In addition, one adult with significant cognitive effects that only occurred while living in the contaminated property had attempted suicide.

Where behavioural assessment forms (BASC-2 or BASC-3) were completed by parents for their children—4 of these reported behaviours that were within the normal range for children of their age, with no indication of any potential clinically significant finding. Most (78%) identified some behavioural indicators that were categorised as “at-risk” or “clinically significant”. One of the children for whom a behavioural assessment form was completed had pre-existing ADHD. The results for this child were excluded from further analyses. For the remaining assessments, behavioural indicators suggested a number of potential clinical issues. These include issues where the behaviours are significantly different to the normal or control population. The results identified mood disorders, principally depressive and anxiety related disorders, as being most common (47%), followed by ADHD (41%) and somatisation and anxiety disorders (23%). This can be compared with the prevalence of anxiety disorders (9.6% for ages 4 to 11 and 7% for ages 12 to 17) and major depressive disorders (1.1% for ages 4–11 years and 5% for ages 12–17 years) in Australian children [ 28 ], and the rate of ADHD rates in school-aged children worldwide of around 5% [ 29 ], with data from Australia indicating 8.2% for ages 4 to 11 and 6.3% for ages 12 to 17 [ 28 ]. Of note is that two of the children, both males who were born and raised in different contaminated properties, have behavioural indicators suggestive of autism spectrum disorder or have been clinically diagnosed with autism spectrum disorder. Based on data from Australia for 2005, autism spectrum disorder affected 0.6% of children aged 6 to 12 years [ 30 ].

The analysis of hair samples collected from participants recently exposed in contaminated properties found methamphetamine above the quantitation limit (5 pg/mg) in 20 of the 36 participants sampled. Table 4 presents a summary of the results for each participant for methamphetamine and amphetamine, alongside the average level of methamphetamine contamination identified in the property in which they were living.

Results of hair analysis for participants.

M = environmental contamination as a result of known or suspected manufacture; U = environmental contamination as a result of known or suspected use (smoking). * = Sample code relates to the case study number, gender of participant and age of participant, e.g., CS12M3 is a participant from CS12, is male, and aged 3 at the time of the study. ** = Indicative average level of MA in properties, noting that the data for each property are variable in terms of the number of samples collected and the type of surfaces sampled.

The highest levels of methamphetamine and amphetamine in the hair samples were from the single female occupant in case study 16 (CS16F47). This situation involved exposure in a residential unit suspected to have been formerly used for manufacture, but it is also suspected that methamphetamine was continuing to be manufactured in adjacent units, meaning exposure was likely to be from both residual contamination and from active manufacture in an adjacent unit.

The hair analysis data showed higher levels of exposure occurring in younger children, which is consistent with the expectation that younger children will have higher levels of exposures due to more common floor play, poorer washing of hands, and mouthing of hands and objects [ 8 , 31 ]. In addition, young children have more porous hair than adults, which would make the hair more susceptible to environmental contamination [ 32 , 33 ].

4. Discussion

4.1. disclosure.

In many of the case studies, issues relating to the lack of disclosure in relation to the presence or potential presence of methamphetamine contamination in a property as a result of known or suspected drug activity were raised as significant issue and stressors. A number of individuals renting properties identified that they felt deceived by the actions of owners or real estate agents, and that this deception resulted in their family being placed in a potentially harmful situation. This was particularly evident where health effects were reported in individuals and family members who moved into these properties, where the deception was considered the cause of the health problems occurring in the property. Once the contamination was discovered, many of these individuals reported increased levels of stress and anxiety.

For one property, CS01, where police discovered it was a former methamphetamine laboratory and the local council had issued a clean-up notice, the property was able to be sold without clean-up due to lack of disclosure of the council notice during the property transaction checks. In addition, the local council continued misleading the new owners about the issue, resulting in the family residing at the property for two years. This affected the health of the family and created significant levels of stress and anxiety, as well as financial loss.

Where contaminated properties have not been identified as former drug laboratories by police but there is knowledge of methamphetamine contamination in a property, there are currently no mechanisms available in Australia to ensure that drug contamination is disclosed to current or future tenants or purchasers. In addition, when property purchasers try to obtain information on potential drug history at the property with police, this information is not disclosed due to privacy laws. These barriers to disclosure have the potential to result in public health risks.

4.2. Health Effects

This study has identified a range of health effects that are associated with living in methamphetamine-contaminated properties. These are properties that have been contaminated as a result of former manufacture or use. Exposures responsible for these health effects are environmental or third-hand exposures, not use or second-hand exposures during use or manufacture. Further, these exposures are unwitting and range from short-term to chronic.

The identification of health effects relied on self-reported health effects. The focus of the reported health effects related to those that occurred while living in a contaminated home that were exacerbated or different from the participant’s health status before moving into the property. Health effects were reported in 67% of participants. The identified change in health was verified on the basis of medical reports and school reports. The school reports were of particular assistance, as these logged changes in visits to the school nurse, as well as behavioural and academic changes reported by teachers. Many of the identified health effects resolved after moving out of the property, further supporting the idea that the source of the reported health effects related to residing in the contaminated property.

There is no one health effect that all study participants consistently reported. The most commonly reported health effects were behavioural effects or issues (79% of children and 65% of adults); sleep issues, such as difficulty sleeping and unusual dreams (72% of children and 68% of adults); and respiratory effects, such as a persistent cough or asthma-like symptoms (62% of children and 53% of adults).

Skin effects, such as rashes or irritation; and eye effects, such as sore or watering eyes, were also commonly reported in both children (55% for skin and 55% for eye effects) and adults (56% for skin and 59% for eye effects).

Headaches were more commonly reported in adults (47%) than children (7%).

The effects were reported in individuals exposed within the properties over a range of durations, varying between infrequent visits to 10 years. The average duration of exposure for all case studies was 2 years and 2 months, with 47% of individuals exposed for less than 1 year. There were no differences in the frequency or type of health effects reported based solely on the duration of exposure.

Once out of the property, these health effects resolved, as noted in Table 3 . Effects on eyes resolving within hours to days, while effects on skin, respiratory system, headaches, and sleep resolving within days to weeks. In some case studies, the resolution of health effects when out of the property while on holidays was one of the first indicators that the home was the cause of their own or family’s health problems, triggering investigation into what was in the home. Behavioural changes also appear to resolve; however, these issues take longer (months to a year). For three participants, depression continued for longer, likely due to prolonged issues in dealing with the contaminated property. In addition, some parents reported ongoing anxiety about their children’s health in the long term.

A common issue relating to the health effects reported for third-hand exposure from methamphetamine-contaminated properties relates to a perception that the health effects commonly reported by individuals are not consistent with those reported from situations with higher levels of exposure, such as during use or exposures by first responders to clandestine drug laboratories. For the key health effects reported in this study, the following provides further supporting evidence of these effects in higher exposure situations.

Skin problems : A number of participants involved in this study identified skin rashes, dry skin patches, and irritation or redness as a health issue that related to being exposed in the contaminated property. The prevalence of these effects was similar for both adults (56%) and children (55%). Within the literature, there are numerous reports of skin issues, including burns, associated with manufacture for first responders [ 34 , 35 , 36 , 37 ] and children exposed during manufacture [ 12 , 38 ]. The use of methamphetamine results in the picking of skin, and in some cases infections [ 39 ]. However, the skin issues reported here are not related to known chemical contact, as would be the case with manufacture, or to skin picking behaviour related to drug-induced psychosis. The skin effects reported in this study related to rashes and hives, and potentially related to contact irritation from residues.

Eyes : Sore and watering eyes were commonly reported in this study in both adults (59%) and children (55%). Eye irritation is also commonly reported by first responders to methamphetamine drug laboratories in the US [ 34 , 35 , 36 , 40 ]. For methamphetamine drug users, vision loss has been reported, likely due to ischaemic optic neuropathy secondary to methamphetamine-induced vasospasm and methamphetamine-associated vasculitis (or inflammation) [ 39 ].

Respiratory effects : A number of participants reported respiratory effects, including a persistent cough, asthma, or asthma-like symptoms (which include shortness of breath and wheezing). In this study, these effects were more commonly reported in children (62%) than adults (53%). Respiratory effects are known to be of key concern for individuals exposed during the manufacture and for first responders, including breathlessness, coughing, sore throat and nose, wheezing, and lung damage [ 34 , 35 , 36 , 37 , 41 , 42 ]. Exposures by first responders have resulted in chronic respiratory effects, including asthma and significantly decreased lung function [ 41 , 42 , 43 , 44 ]. Short-term methamphetamine abuse is associated with an increased rate of breathing and constriction in blood vessels, while long-term abuse is associated with decreased lung function and pulmonary hypertension [ 45 ].

In addition, the effects of accidental ingestion of methamphetamine by children include acute respiratory problems [ 46 ].

In relation to environmental exposures, there are some other reports of respiratory effects. Exposures in former methamphetamine drug laboratories include breathing difficulties reported in a 1 year old child [ 12 ] and asthma reported in another child [ 46 ] in the US. Respiratory effects (sinus problems in all members of the family and breathing difficulties in a newborn baby) were reported in a family who lived for 5 months in a former methamphetamine drug laboratory in Utah [ 47 ].

Immune issues : Immune issues, particularly chronic or recurring respiratory and sinus infections, were reported by 32% of adults and 24% of children. It is noted that for some case studies where occupation in the home was for a short period of time, it was more difficult to determine whether the recurring infections were related to exposure in the contaminated property or caused by being in the cold and flu season. However, it was clear from the interviews undertaken that in some case studies participants were more significantly affected by respiratory or sinus infections while living in the contaminated property. Exposures by first responders to methamphetamine laboratories have resulting in effects on the immune system [ 41 , 42 , 43 , 44 ].

Headache : A number of participants, particularly adults (47%), reported an increase in the number or severity of headaches while living in the contaminated property. For two of the participants from two different case studies, the severity of headaches was so severe that it required hospitalisation and investigation. Other than the changed exposure environment, no other cause of the headaches was identified in either case. On moving out of the property these headaches improved significantly. Headache has been reported as an issue for first responders to methamphetamine laboratories [ 12 , 34 , 35 , 36 , 42 ], as well as properties suspected as former clandestine laboratories [ 12 ]. Headaches are also reported in methamphetamine users [ 48 , 49 ].

Sleep issues : Difficulty sleeping, including regularly waking up, and unusual dreams were commonly reported in both adults (68%) and children (72%). In a number of case studies, ongoing sleep issues resulted in participants reporting that they were constantly fatigued or tired. When staying out of the contaminated home, most participants reported that their sleep improved within days. This was also reported by parents for children, with sleep improving when out of the home, even where the new location was unfamiliar. Methamphetamine as a single acute dose or repeated administration is known to disrupt sleep in users, even when administered 12 h of more prior to a sleep assessment [ 50 ], with low doses used in clinical settings resulting in arousal [ 49 ].

Behavioural and cognitive effects : A number of participants reported behavioural changes or cognitive effects when living in or visiting the contaminated properties. Overall, this included 65% of adults and 79% of children. A range of different types of behavioural and cognitive effects were reported.

In adults, the most common effects reported related to tiredness and fatigue, which likely resulted from sleep issues, as well as increased moodiness, depression, and anxiety. In some participants with pre-existing depression issues, exposure in the contaminated property significantly exacerbated their symptoms. In relation to the cognitive effects, some participants reported feeling vague and not thinking clearly, as well as memory issues. Effects on memory [ 42 ] and mood swings have been reported by first responders to methamphetamine laboratories in the US [ 34 , 35 ]

In children, the most significant effect reported related to increased levels of aggression or irritability, along with increased levels of tiredness and fatigue. These may also be related the sleep issues reported in children living in these properties. For a number of children exposed in these properties, a behavioural assessment was undertaken using a standardised test (BASC-2 or BASC-3). The behavioural issues reported in these case studies are consistent with many of those reported in children removed from methamphetamine drug laboratories [ 51 , 52 , 53 , 54 , 55 ], where there is the assumption that the level of exposure is higher. More specifically, these common behavioural issues include internalising (depression, anxiety, and somatisation) problems, externalising (acting out and hyperactivity) problems, attention problems, and aggressive behaviour [ 51 , 52 , 53 , 54 , 55 ]. However, unlike the behavioural issues reported in children removed from methamphetamine drug laboratories, the effects reported in these case studies are not confounded by other risk factors associated with drug use, criminal behaviour, abuse, and neglect. Another common behavioural issue reported by case study participants was the change in sleep patterns, in particular trouble sleeping. A lack of sleep or significant changes in sleep patterns can also result in changes in behaviour (in particular depression, anxiety, and mood disorders) and a lack of concentration [ 56 ].

In general, exposures to amphetamines have been associated with neurochemical changes in areas of the brain that are associated with learning, potentially affecting cognitive function, behaviour, motor activity, and changes in avoidance responses [ 45 ]; and physiological, behavioural, and developmental effects, including psychosis, violent behaviour, depression, irritability, hallucinations, mood swings, paranoia, and sleep disorders [ 45 , 57 , 58 , 59 , 60 , 61 ], with the available data also suggesting cognitive decline or deficits [ 62 , 63 ]. Limited studies on the effects of methamphetamine in adolescents [ 64 ] indicate increased levels of depression, anxiety, and risky sexual behaviours, with animal studies indicating impaired cognitive function [ 65 ].

Other effects : While cardiac effects are considered to be one of the major health effects associated with methamphetamine use [ 61 ], effects associated with significant cardiac changes were only reported by one adult participant in this study. One other participant also provided evidence of increased blood pressure and the requirement to double the dose of medication controlling blood pressure while living in the contaminated property. Another commonly reported adverse effect in methamphetamine users relates to dental issues [ 39 ]. A child from one of the case studies reported problems with the development of all four molars, which was unusual and could not be explained by their dentist.

An observation provided by one adult participant who was a former drug user is that the effects experienced while living in a contaminated property were consistent with the adverse effects of methamphetamine drug withdrawal. Methamphetamine withdrawal syndrome is characterised by disturbed sleep, including insomnia; depressed mood and anxiety; craving and cognitive impairment; along with agitation, vivid, or unpleasant dreams and reduced energy [ 49 ]. A number of these health effects are consistent with those reported in the presented case studies.

4.3. Hair Analysis

Not all study participants provided a hair sample for analysis. In a number of cases, this was due to the time period during which they were involved in the study, i.e., they were involved too long after exposure had ceased for any exposure to be able to be detected in the hair (particularly for males with short hair), or the period of exposure in the contaminated property was too short to be able to reliably detect exposure. In some circumstances, hair samples were collected from participants where short-term exposures occurred.

The detection of methamphetamine, and in some cases amphetamine, in the analysis of hair samples from exposed participants, as presented in Table 2 , indicates that for some situations environmental exposure was sufficient to be able to be detected in the hair. This is not the case for all situations, as there were a number of participants for whom analysis of a hair sample could not detect methamphetamine.

Amphetamine is the major metabolite of methamphetamine, and the detection of both methamphetamine and amphetamine is generally considered to be indicative of systemic absorption of methamphetamine [ 66 , 67 ], however amphetamine is noted to also be present from the manufacture of methamphetamine in clandestine drug laboratories, which can complicate interpretation of the data.

Amphetamine was detected in the hair analysis of five participants. Where detected, the methamphetamine-to-amphetamine (MA/AMP) ratio was calculated to range between 11 and 23. For CS16F47, methamphetamine was not fully quantified due to the high level detected (>2500 pg/mg), meaning a MA/AMP ratio was not calculated. The range of MA/AMP ratios reported in this study is consistent with the range of 5.7 to 69 and the mean value of 21 reported for hair samples collected from children removed from clandestine drug laboratories [ 66 ]. This range was also consistent with the range of 8.6 to 59 and the mean value of 26 recorded for drug-exposed children from the manufacture and use of methamphetamine [ 67 ]. For drug users, the MA/AMP ratio is typically around 10 [ 68 ], with a reported range of 3 to 50 [ 69 ]. This ratio has been found to increase with the duration of drug abuse [ 70 ], and presumably environmental exposures.

Based on the MA/AMP ratio from this case study, an estimate of the level of amphetamine that may have been present in the hair of other participants (where methamphetamine was detected) found that the level of AMP in hair for these samples would be below the detection limit of the analysis method.

In relation to the hair washing results, for six participants methamphetamine was detected. The ratio of methamphetamine in the washed hair was in the range of 0.2 to 0.47. Ratios greater than 0.1 have been suggested [ 71 ] as indicative of some external contamination. The ratios reported in this study range up to 0.5, a level above which it is suggested that external contamination is significant [ 71 ]. This suggests that external contamination of the hair occurred when living in the home, potentially via deposition from the air and direct contact of the hair with hands and surfaces, such as couches and bedding. Where personal possessions were analysed in the case studies included in this study, this data indicated the presence of methamphetamine contamination of possessions brought into the property, supporting the potential for contaminant mobility and external contamination to occur, supporting our previous findings [ 6 ].

For adults, methamphetamine was detected in hair in case studies where the mean environmental methamphetamine concentration was in the range 7.8 to 49 µg/100 cm 2 , which predominantly involved properties where clandestine drug manufacture was known or suspected to have occurred. The concentrations of methamphetamine detected in adult hair ranged from 5 pg/mg to 80 pg/mg, with one individual result reported as >2500 pg/mg. The property where the average contamination level was 7.8 µg/100 cm 2 may have been related to manufacture or use. There were some properties with contamination levels in this range where no detectable levels of methamphetamine were reported in hair. This variability is expected to reflect individual exposure patterns. Higher levels of methamphetamine were reported in hair where the participant was the primary cleaner for the property, spent more time at home, or had a habit of chewing fingernails. The highest level of methamphetamine reported in hair (>2500 pg/mg) related to a situation where there were co-exposures with a neighbouring active manufacturing operation, which also resulted in the highest average level of methamphetamine contamination in the property (49 µg/100 cm 2 ).

In relation to children, methamphetamine was detected in hair for case studies where the mean environmental methamphetamine concentration was in the range of 2.8 to 30.7 µg/100 cm 2 . The concentration of methamphetamine detected in the hair of children ranged from 6 to 980 pg/mg. This included properties contaminated as a result of both use and manufacture.

Concentrations of methamphetamine detected in hair above the quantitation limit (5 pg/mg) were plotted against the average concentration of methamphetamine reported in the premises these individuals resided in, which are presented in Figure 1 for all individuals (adults and children) and separately for children. While it is noted that there are limitations in the data relating to the characterisation of methamphetamine residues in each property, the figures show a linear relationship between the environmental exposure levels in the premises and the hair concentrations, with the relationship being stronger for all individuals where hair samples were collected (r 2 of 0.44) than for the samples collected from only the children (r 2 of 0.22).

Relationship between environmental methamphetamine (MA) in individual premises and in hair samples collected from individuals exposed in these properties.

Three of the case studies (CS01, CS22, and CS23) included families exposed in contaminated properties where methamphetamine was detected in hair in both adults and young children. The concentrations of methamphetamine reported in these case studies are shown in Figure 2 . For these case studies, the level of methamphetamine reported in hair follows a pattern consistent with what is expected for environmental exposures, with higher levels reported in younger children who have higher levels of exposure to surfaces, objects, and materials in the home. The exception is CS23, where one of the adults, the children’s nanny, had higher levels of methamphetamine than the mother. This may be due to exposures that occur during close play with young children. The highest levels were reported in the youngest children. Figure 3 shows the concentrations of methamphetamine by age in all participants from exposure to methamphetamine residues in all properties, which shows the decreasing levels of methamphetamine detected in hair with increasing age of the participants exposed.

Methamphetamine levels (pg/mg) in hair for families from three case studies (note different scale on the y axes).

Methamphetamine levels (pg/mg) detected in hair by age for all participants exposed to environmental methamphetamine residues in case studies.

The levels of methamphetamine found in hair in this study, particularly in the children’s hair from CS01 and CS22, were at the lower end of the range reported in adults and children from properties where methamphetamine was actively used or manufactured [ 66 , 67 ] and the range reported for adult drug users [ 72 , 73 ]. The ranges of methamphetamine reported in hair in these studies were 100–131,000 pg/mg for children and 100–128,100 pg/mg for adults, noting that a reporting cut-off of 100 pg/mg was adopted in these studies. A study of passive exposures by children in families where one or both parents used drugs reported detectable levels of levels of amphetamines (MA + AMP) in 80% of the situations where these drugs were used by the parents, with concentrations of 140 to 890 pg/mg reported in the hair of children aged 7 to 10 years [ 33 ]. These studies also showed that the higher levels of methamphetamine in hair were reported for children aged 5 years and younger, with a decreasing trend with increasing age. This is consistent with the behaviours of young children, including increased floor play, a higher potential for touching walls and other surfaces in the home, a higher potential for placing hands and objects in the mouth, less frequent washing of hands prior to eating, and more time spent indoors, all of which may result in higher levels of exposure. It is also suggested that the finer and more porous nature of the hair of children aged up to around 3 years may facilitate incorporation from external contamination [ 33 ]. Where children are exposed to residues in contaminated properties, as is the case for this study, incorporation from external contamination is expected to be a contributing factor in the levels reported in hair.

4.4. Use vs. Manufacture

While some data are available relating to health effects and exposures that occur during and post manufacture of methamphetamine, data are lacking in relation to health effects and exposures that occur as a result of residues derived from the smoking of methamphetamine.

This study has included data collected from properties and participants exposed to methamphetamine residues as a result of either known or suspected manufacture or use alone. For some case studies, the source of contamination was not clear, and hence manufacture and use were both been considered. The information provided on the likely source came from police reports, media reports of police activity, observations of property owners in relation to evidence of manufacture or use, and information from neighbours on the behaviour of previous occupants and presence of unusual odours. As a result, while this evidence has been used to categorise the contamination as being derived from manufacture or use, it cannot be confirmed. Both manufacture and use by previous occupants are illegal activities, and hence it is not possible to be more accurate in determining the most likely source of contamination.

Figure 4 presents a summary of the data collected from contaminated premises and participants, separated into the three different exposure situations: manufacture; manufacture and/or use; and use. This figure shows the range of average methamphetamine environmental levels reported in properties—the results of hair samples collected encompass higher levels for manufacture compared with use. Despite the reduced range of methamphetamine environmental levels reported in properties contaminated from use, it is not possible to preclude contamination from manufacture simply on the basis of the lower levels of environmental contamination reported, as the lower levels of environmental contamination were also reported in properties where manufacture was known, suspected, or cannot be precluded. The presence of higher average methamphetamine environmental levels could be used to identify properties associated with former manufacture.

Summary of exposure and health data by exposure situation for manufacture and use.

Similarly, the range of methamphetamine concentrations reported in hair was lower for participants exposed in properties contaminated from use. However, lower levels, including levels below the detection limit, were also reported in properties where contamination from manufacture was known, suspected, or could not be precluded.

In terms of health effects reported by participants exposed in contaminated properties, these were consistently reported regardless of the source of the methamphetamine contamination. The only key difference in the health effects reported was a higher prevalence of eye and respiratory issues in properties known or suspected to have been contaminated from manufacture. The presence of contamination and public health risks from use are generally poorly addressed in guidelines, which predominantly focus on contamination from manufacture. The data presented in this study indicate that contamination from exposure alone is a potential significant public health issue.

4.5. Guidelines

Guidelines for the assessment of methamphetamine-contaminated properties are currently available in Australia and internationally. In Australia, guidelines are available for methamphetamine in residential homes, as well as commercial or industrial premises [ 74 ]. These are risk-based guidelines that adopt a range of assumptions about the way in which people are exposed to methamphetamine in a property via dermal absorption and ingestion only, which involve published quantitative toxicity reference values [ 75 ]. As a result, the guidelines are intended to be protective of the health of individuals exposed in methamphetamine-contaminated properties. Any such guidelines should have a margin of safety such that observable health effects would not be expected with exposure in premises where methamphetamine contamination is at or just above the guideline.

The data presented here cannot be used to identify an average level of environmental methamphetamine exposure below which no health effects are reported. This is principally due to the reporting of health effects associated with exposure in the contaminated properties over a wide range of contamination levels, including case studies where the average methamphetamine level was less than or close to the current Australian residential guideline of 0.5 µg/100 cm 2 . There were three case studies where the average environmental methamphetamine levels were below this guideline.

CS15 was exposed to the lowest average environmental methamphetamine contamination level of 0.063 µg/100 cm 2 . Health effects were reported in this case study for both participants—an adult with a pre-existing illness and a 13-year-old child with pre-existing asthma. The reported health effects included skin and eye irritation, persistent cough, exacerbation of asthma, sleep issues, headaches, and behavioural changes, including increased depression and anxiety in the child and vagueness in the adult. In this case study, medical and school reports were provided showing evidence of the health effects reported during occupancy of the property. The property was remediated by the owner despite the environmental methamphetamine levels being below the Australian guideline for residential properties. Following remediation, the reported health effects resolved as the family continued to live in the property post-remediation.

CS06 was exposed to an average environmental methamphetamine contamination level of 0.31 µg/100 cm 2 . This case study included one adult participant for whom health effects were reported. These health effects included skin and eye irritation, persistent cough, depression, fatigue and vagueness, dizziness, nausea, and weight loss. Medical reports were provided to support the reported health effects. Apart from depression, the health effects resolved on moving out of the property. The persistent depression was likely exacerbated by ongoing issues related to resolving financial losses that occurred when living in and moving out of the contaminated property.

CS21 was exposed to an average environmental methamphetamine contamination level of 0.36 µg/100 cm 2 . This case study included one 16-year-old participant for whom health effects were reported, which included skin rashes, persistent cough, and vagueness. Medical reports were provided to support the reported health effects. These health effects resolved after moving out of the property.

None of the three case studies discussed above included analysis of a hair sample.

For the case studies where hair analysis was undertaken, the lowest average environmental methamphetamine level that resulted in a detection of methamphetamine in hair was CS05. This property had an average environmental methamphetamine level of 2.8 µg/100 cm 2 and trace levels of methamphetamine were reported in the 13-year-old participant residing in the property. This property is suspected to have been contaminated as a result of use only. Other case studies with lower levels of average environmental methamphetamine that were up to approximately 10 times above the Australian guideline, CS18 and CS12, also reported trace levels of methamphetamine in the hair of children residing in these properties. Methamphetamine was not detected in the hair samples collected from adults in these properties. These data demonstrate that environmental methamphetamine exposure and intake is occurring at properties more commonly considered to have low levels of methamphetamine contamination.

One of the key issues identified with the data reported in this study is the use of environmental methamphetamine data collected by other parties or investigators, which resulted in the sampling of different surfaces and materials in each case study. Hence, there is the potential that higher levels of methamphetamine contamination may be present in the properties in unsampled areas where participants may be regularly exposed. This is, however, a real issue, as decisions in relation to contamination levels and remediation are based on the same types of assessments undertaken by investigators that were used in this study. While it is accepted that some of these assessments will have considered property-specific aspects, the variability in the numbers of samples collected and the types of materials sampled is significant. This complicates the review of the data presented in this study; however, this study has relied on the same data that participants, regulators, and industry would rely on when making decisions about the property. This suggests that more robust training may be required for investigators to minimise the potential to underestimate, or even overestimate, environmental methamphetamine levels in properties [ 76 ].

4.6. Study Limitations

This study has included data from opportunistic case studies only. The issues addressed relate to contamination from former illegal activities, and hence information is limited or unavailable in relation to the source of contamination (manufacture or use) and locations of the properties where such activities may have occurred.

Data provided in relation to environmental methamphetamine levels in the properties were from investigations undertaken by others for the purpose of characterising contamination. As a result, the data were mixed in terms of those collecting the samples, the number of samples collected, as well as the surfaces that were sampled within each property. While these are the same data that are relied on for making decisions about the contamination status of a property, the variability in the sampling makes it more difficult to compare results between properties.

This study relied on self-reported health effects for participants. This information specifically focused on health issues that were different while residing in the contaminated property, rather than just the participants’ current health status. Participants were asked to provide health information in relation to exposures prior to their knowledge or confirmation that the property was contaminated. In addition, this study obtained or cited medical and school reports supporting these observations for 67% of the participants. While all attempts were made to limit reporting bias from participants, it is expected that this will be present. It is also not possible to preclude other issues inside each property that may have contributed to or affected participant health.

5. Conclusions

This study has identified a range of health effects that occur while residing in contaminated properties, which include behavioural effects or issues, sleep issues, respiratory effects, skin and eye effects, and headaches. In addition, methamphetamine was also detected in the analysis of hair samples collected from a number of individuals, including children exposed at these properties. In general, higher levels of methamphetamine were reported in hair samples from individuals exposed in properties with higher levels of environmental methamphetamine contamination. The exposures and health effects reported occurred following exposure to properties contaminated as a result of known or suspected manufacture or use over a wide range of environmental methamphetamine levels in the property, which included levels close to the current Australian guideline of 0.5 µg/100 cm 2 . There were no discernible differences in exposures or health effects reported in properties contaminated from former manufacture or use.

The characterisation of contamination at these types of properties is complex, as are the situations in which exposure has occurred in each of the case studies evaluated, with the majority of these properties not being known to have had a drug history prior to occupancy. This study has demonstrated that these properties have the potential to be a significant public health risk. It is, therefore, important that these properties are properly identified and cleaned up and that procedures are developed to ensure that clean-up occurs. Additionally, properties known to be contaminated but not cleaned up need to be disclosed to future occupants.

Acknowledgments

Donations in kind for analysis of hair samples by Forensic Science SA. Donations in kind for travel costs by Environmental Risk Sciences Pty Ltd.

Author Contributions

Conceptualisation and methodology, J.W., K.R., and S.W.; investigation, formal analysis, and writing—original draft preparation, J.W.; methodology and hair analysis, M.K.; writing—review and editing; K.R., M.K., and S.W. All authors have read and agreed to the published version of the manuscript.

This research received no external funding.

Conflicts of Interest

The authors declare no conflict of interest.