radon case study answer key

Environmental Medicine: Integrating a Missing Element into Medical Education (1995)

Chapter: case study 38: radon toxicity.

14 Radon Toxicity

This monograph is one in a series of self-instructional publications designed to increase the primary care provider’s knowledge of hazardous substances in the environment and to aid in the evaluation of potentially exposed patients. See pages 21 to 23 for further information about continuing medical education credits and continuing education units.

U.S. DEPARTMENT OF HEALTH & HUMAN SERVICES

Public Health Service

Agency for Toxic Substances and Disease Registry

Chronic cough and weight loss in a nonsmoking 56-year-old woman

A 56-year-old housewife seen at your office has a 3-month history of chronic, nonproductive cough, which has recently become unresponsive to over-the-counter liquid cough suppressants. She denies having shortness of breath, wheezing, chest pain, hemoptysis, fever, chills, sore throat, hoarseness, or postnasal drip. Her cough is independent of time of day, physical activity, weather conditions, and exposure to dust or household cleaning agents. Furthermore, her daughter’s cigarette smoke does not seem to aggravate the cough. She notes that she has been feeling fatigued and, without dieting, has lost 18 pounds over the past 6 months.

Her past medical history is noncontributory. She is a nonsmoker and nondrinker and does not come in contact with any known chemical substances or irritants other than typical household cleaning agents. Her father died at age 65 of a myocardial infarction, and her mother had breast cancer at age 71. Her first husband died of a cerebrovascular accident 3 years ago. Newly remarried to a retired shipyard worker, she and her current husband live with her 28-year-old daughter and 9-year-old grandson in their New Hampshire home. She has not been outside the New England area for the last 5 years.

Results of the physical examination, including HEENT and chest examination, were normal. There is no cyanosis or clubbing of the extremities, and there are no palpable lymph nodes. Blood tests, including a complete blood count and chemistry panel, are normal, with the exception of a total serum calcium level of 12.7 mg/dL (normal range: 9.2 to 11.0 mg/dL). However, a chest radiograph reveals a noncalcified, noncavitary 3.5-cm mass located within the parenchyma adjacent to the right hilum. There are no other radiographic abnormalities. Results of a PPD skin test for tuberculosis are negative. Urinalysis results are normal.

(a) What is the differential diagnosis for this woman’s condition?

_________________________________________________________________

(b) What further testing might you order?

(d) What treatment options might you consider?

Answers can be found on page 18.

Exposure Pathways

Sources of radon exposure.

❑ Radon, a colorless, odorless gas, is both chemically inert and imperceptible; it decays into a series of progeny, some of which are short-lived and emit bursts of harmful alpha particles.

❑ Soil is the main source of indoor radon; however, building materials and water supply can also be sources.

Radon gas is derived from the radioactive decay of radium, a ubiquitous element found in rock and soil. The decay series begins with uranium-238 and goes through four intermediates to form radium-226, which has a half-life of 1600 years. Radium-226 then decays to form radon-222 gas. Radon’s half-life, 3.8 days, provides sufficient time for it to diffuse through soil and into homes, where further disintegration produces the more chemically and radiologically active radon progeny (“radon daughters”). These radon progeny, which include four isotopes with half-lives of less than 30 minutes, are the major source of human exposure to alpha radiation (high-energy, high-mass particles, each consisting of two protons and two neutrons). This alpha radiation is responsible for cellular transformation in the respiratory tract, which results in radon-induced lung cancer.

Radon itself is imperceptible by odor, taste, and color, and causes no symptoms of irritation or discomfort. There are no early signs of exposure. Only by measuring actual radon levels can persons know whether they are being exposed to excessive levels of radon gas. Radon seeps from the soil into buildings primarily through sump holes, dirt floors, floor drains, cinder-block walls, and through cracks in foundations and concrete floors ( Figure 1 ). When trapped indoors, radon can become concentrated to dangerous levels. When radon escapes from the soil to the outdoor air, it is diluted to levels that offer relatively little health risk.

Radon gas can enter a building by diffusion, but pressure-driven flow is a more important mechanism. Negative pressure in the home relative to the soil is caused by exhaust fans (kitchen and bathroom), and by rising warm air created by fireplaces, clothes dryers, and furnaces. In addition to pressure differences, the type of building foundation can affect radon entry. Basements allow more opportunity for soil gas entry, but slab-on-grade foundations (no basement) allow for less. In most cases, the slight increase of indoor radon due to home “tightening” for energy conservation is small in comparison with the amount of radon coming from the soil.

❑ Although slab-on-grade foundations allow for less soil gas entry than do basements, both types of foundations could permit entry of radon.

Normally, construction materials do not contribute significantly to indoor radon levels. In rare cases, however, building materials themselves have been the main source of radioactive gas. Building materials contaminated with vanadium mill tailings in Monticello, Utah, and uranium mill tailings in Grand Junction, Colorado, were an important source of radon. (Tailings consist of the sand-like material remaining after minerals are removed from ore.) Also, concrete made from phosphate slag in Idaho and Montana and insulation from radium-containing phosphate waste from the state of Washington have been found to emit high levels of radon.

Figure 1 . Sources of radon and common entry points

Radon may be carried into some homes via the water supply. With municipal water or surface reservoirs, most of the radon volatilizes to air or decays before the water reaches homes. However, water from private wells may be another matter. Groundwater that comes from deep subterranean sources and passes over rock rich in radium, such as that found in northern New England, may dissolve some of the radon gas produced from radium decay. As the water splashes during showering, toilet flushing, dishwashing, and laundering, radon is released into the air and may result in inhalation exposure. Radon may also be present in natural gas supplies.

Hazard Assessment

Respiratory dose and units of measure.

❑ Radon can be detected only by testing.

Since the health effects of radon are insidious and have a long latency period, it is important to measure exposure to the gas empirically. Techniques for measuring radon are discussed below, in the subsection entitled Radon Detection (p. 11). Included here is a review of the basic unit of radon measurement and the factors that affect the risk associated with radon exposure.

The relationship between exposure to radon and the dose of decay products that reaches target cells in the respiratory tract is complex. Some factors that influence the pulmonary radiation dose include the following:

❑ EPA recommends remediation for homes with radon levels at or above 4 pCi/L.

characteristics of the inhaled air —free or unattached radon progeny deposit more efficiently than progeny attached to dust or other particles; of the attached progeny, only those adhering to the smallest particles are likely to reach the bronchi

amount of air inhaled —the amount and deposition of inhaled radon decay products vary with the flow rate in each airway segment

breathing pattern —the proportion of oral to nasal breathing will affect the number of particles reaching the airways

architecture of the lungs —sizes and branching pattern of the airways affect deposition; these patterns may differ between children and adults, and between males and females

biologic characteristics of the lungs —the dose increases as the mucociliary clearance slows and diminishes with increasing thickness of the mucous layer

It is possible, therefore, that two environments with the same radon measurement (e.g., a dusty mine and a home environment) may deliver different doses of alpha radiation to a person’s lungs. Likewise, two persons in the same environment may receive differing doses of alpha radiation to the target cells of their lungs because of differing breathing patterns and pulmonary architecture.

The concentration of various progeny is ultimately related to lung injury and thus might be the most appropriate measure of respiratory exposure. On the basis of both animal and human data, it can be assumed, however, that the higher the radon level a person experiences, the more likely it is that the person will develop lung cancer. For convenience, indoor air measurements, therefore, usually measure radon gas itself. These measurements are expressed in picocuries per liter (pCi/L) of air, where a picocurie is equivalent to 0.037 disintegrations per second. The U.S. Environmental Protection Agency (EPA) has recommended that remedial action be taken to lower the amount of radon in homes if the measured level is 4 pCi/L or greater.

Risk Estimates

❑ For a lifetime exposure at EPA’s recommended guideline of 4 pCi/L, EPA estimates that the risk of developing lung cancer is 1% to 5%, depending on whether a person is a smoker, former smoker, or nonsmoker.

Even conservative estimates based on current knowledge suggest that radon is one of the most important environmental causes of death. EPA estimates that approximately 14,000 deaths annually in the United States are due to lung cancer caused by indoor radon exposure. It has also been estimated that approximately 14% of all current cases of lung cancer are attributable to radon.

For a lifetime exposure to radon at 4 pCi/L, EPA estimates that the risk of developing lung cancer is 1% to 5%. The National Research Council estimates the risk at 0.8% to 1.4%.

❑ The overall risk of radon exposure is related not only to its level in the home, but also to the occupants and their lifestyles.

Many factors influence the risk of lung cancer due to radon exposure; among these are age, duration of exposure, time since initiation of exposure, and cigarette smoking ( Figure 2 ). In assessing the risk of radon in a home, one must consider not only the level of radon, but also the occupants and their lifestyles. Are there any smokers? Any children? How much time is spent in the home? Where do occupants sleep? The highest radon levels are typically found in the lowest level of the house. If well water is the major source of radon, upper floors can be affected more than lower floors. In colder climates, radon levels are often higher in the winter and lower in the summer.

Figure 2 . Radon risk evaluation chart

RADON RISK IF YOU SMOKE

RADON RISK IF YOU’VE NEVER SMOKED

Who’s at Risk

❑ Miners in uranium and other types of underground mines may have increased radon exposure.

❑ Approximately 6 million homes in the United States have radon levels above 4 pCi/L.

❑ Exposure to excessive radon levels increases the already elevated risk of lung cancer for smokers.

As early as the 16th century, Paracelsus and Agricola described a wasting disease of miners. In 1879, this condition was identified as lung cancer by Herting and Hesse in their investigation of miners from Schneeberg, Germany. Radon itself was discovered some 20 years later by Rutherford. Subsequently, an increase in the incidence of lung cancer among miners was linked to radon exposure in mines. Underground uranium mines found throughout the world, including the western United States and Canada, pose the greatest risk because of their high concentration of radon. Iron ore, potash, tin, fluorspar, gold, zinc, and lead mines also have been found to have significant levels of radon, often due to radium in the surrounding rock. In the past, it was not uncommon to use the tailings from these mines as fill on which to build homes, schools, and other structures.

Indoor radon has been widely recognized as a potential problem in Europe and the Scandinavian countries since the 1970s. Public awareness in the United States was heightened in December 1984, when Stanley Watras, a worker at the Limerick nuclear plant in Pennsylvania, began setting off radiation alarms when he entered the plant. The cause was traced to excessive radon levels in his home, which were found to be 500 times the level at which EPA currently recommends remediation (4 pCi/L).

In 1987, the federal government allotted $10 million to the states to determine the extent of radon contamination in homes and schools and subsequently amended the Toxic Substances Control Act to assist the states “in responding to the threat to human health posed by exposure to radon.” In 1988, EPA and the Office of the Surgeon General jointly recommended that all U.S. homes below the third floor be tested for radon. In 1990, Congress appropriated $8.7 million for grants to states to develop and enhance programs to reduce radon risk in homes and schools. It has become standard practice in some states to measure radon levels in homes at the time of real estate transactions.

The amount of radon emanating from the earth and concentrating inside homes varies considerably by region and locality. Nearly every state in the United States has dwellings with measured radon levels above acceptable limits. EPA estimates that 6% of American homes (approximately 6 million) have concentrations of radon above 4 pCi/L. In Clinton, New Jersey, near a geologic formation high in radium called the Reading Prong, all 105 homes tested were above the recommended guidelines; 40 had levels exceeding 200 pCi/L. In the Stanley Watras home, levels of 2700 pCi/L were found in the basement.

Areas of the country that are likely to have homes with elevated radon levels are those with significant deposits of granite, uranium, shale, and phosphate—all high in radium content and, therefore, potential sources of radon gas. Some homes in these areas, however, may not have elevated levels of radon. Due to the many determinants of indoor radon levels, local geology alone is an inadequate predictor of risk.

Currently, the only way to determine indoor radon concentration is by testing. A home located 100 feet away from the Watras’ home did not have measured radon concentrations that required remediation, yet both houses are located on the same geologic formation. Other factors found to predispose homes to elevated levels of radon include soil porosity, foundation type, location, building materials used, entry points for soil gas, building ventilation rates, and source of water supply. Further research is being conducted on ways to predict which homes are most likely to have significant levels of radon.

Several studies have shown that smokers exposed to radon are at greater risk for lung cancer than nonsmokers similarly exposed. It is generally believed that exposure to radon and cigarette smoking are synergistic; that is, the combined effect exceeds the sum of their independent effects. The risk of lung cancer from radon exposure is estimated to be 10 to 20 times greater for persons who smoke cigarettes in comparison with those who have never smoked. According to the EPA Office of Radiation Programs, a breakdown of the contribution of smoking and radon exposure to lung cancer deaths in the United States illustrates that of every 100 persons who have died of lung cancer, approximately 70 were current smokers, 24 were former smokers, and 6 had never smoked. It is estimated that radon contributed to 20% of the deaths in each category.

Data on the effects of radiation in children are limited, and even less is known about the effects of radon exposure in this age group. Cancer development in Japanese atomic bomb survivors suggests an increased susceptibility to radiation in children compared with that in adults. Children also have different lung architecture, resulting in a somewhat more concentrated dose of radiation to the respiratory tract, and children have a longer latency period ahead of them in which to develop cancer. However, there are currently no conclusive data on whether children are at greater risk than adults from radon.

Physiologic Effects

❑ The primary adverse health effect of exposure to radon is lung cancer.

❑ The synergistic mechanism(s) of cigarette smoking and radon exposure are not known, although the adverse health effects of the combination are clear.

Radon exposure causes no acute or subacute health effects, no irritating effects, and has no warning signs at levels normally encountered in the environment. The only established human health effect currently associated with residential radon exposure is lung cancer. Epidemiologic studies of miner cohorts have reported an increased frequency of chronic, nonmalignant lung diseases such as emphysema, pulmonary fibrosis, and chronic interstitial pneumonia, all of which increased with increasing cumulative exposure to radiation and with cigarette smoking.

Epidemiologic studies and a recent study of groundwater radon and cancer mortality have found no association with extrapulmonary cancers, such as leukemias and gastrointestinal cancers. There is also no evidence that environmental radon exposure is causally associated with adverse reproductive effects.

❑ Radon progeny can be inhaled either as free particles or attached to dust. Free progeny preferentially deposit in the bronchi, the site of most lung cancers.

Due to their charged state and solid nature, radon progeny rapidly attach to most surfaces they encounter, including walls, floors, and airborne particulates. They can be inhaled, therefore, either as free, unattached particles or attached to airborne dust. The smaller dust particles can deposit the radon progeny deep in the lungs. Being ionized, the progeny tend to attach to the respiratory epithelium. Through mucociliary action, the progeny are eventually cleared from the respiratory tract, but because of their short half-life, they can release alpha particles before being removed. The total amount of energy deposited by the progeny is approximately 500 times that produced in the initial decay of radon. When these emissions occur within the lungs, the genetic material of cells lining the airways can be damaged, resulting in lung cancer.

The risk of lung cancer due to radon exposure is thought to be second only to that of smoking. The synergism between cigarette smoking and radon places the large population of current and former smokers at particularly high risk for lung cancer. Although the net consequence of cigarette smoking and exposure to radon decay products has been clearly demonstrated in smokers, the mechanism of interaction is still unclear.

Most of the lung cancers associated with radon are bronchogenic, with all histologic types represented. However, small cell carcinoma occurs at a higher frequency among both smoking and nonsmoking populations of underground miners in the initial years following exposure compared with the pattern of histologic types in the general population. Other types of lung cancers seen in radon-exposed miners are squamous cell carcinoma, adenocarcinoma, and large cell carcinoma.

Treatment and Management

❑ Generally, the most effective methods to reduce the risk of lung cancer are smoking cessation and radon mitigation.

❑ The risk of cancer due to radon is often underestimated by the public; this bias may discourage assessment and abatement measures in the home.

Currently, no effective communitywide screening methods are available for medical prevention or early diagnosis and treatment of lung cancer (radon-induced or otherwise). Routine chest radiographs and sputum cytology are ineffective for lung cancer screening associated with cigarette smoking and would presumably be ineffective for lung cancer associated with radon as well. The most effective methods of prevention are reduction of radon exposure and modification of other simultaneous risk factors for lung cancer, such as smoking. Smoking cessation coupled with detection and mitigation of high radon levels is currently the only long-term solution for reducing the risk of lung cancer.

Several studies have noted optimistic biases in the public’s assessment of the risk due to radon. A New Jersey study found that this bias may discourage testing and subsequent implementation of control measures. In Maine, homeowners were found to greatly underestimate the risk, and abatement behavior was not significantly related to the actual risk.

Primary care physicians and public health professionals should promote public awareness so that the radon problem is seen in the proper perspective, leading to appropriate mitigation action when indicated. Physicians and public health officials should therefore test their own homes to relate their experience to others and to provide guidance on how to carry out the testing.

Radon Detection

❑ Radon levels cannot be predicted; they must be measured.

Radon levels cannot be accurately predicted solely on the basis of factors such as location, geology, home construction, and ventilation. A recent survey of Connecticut homes indicates that the age of the house and the presence of a cinder-block foundation have a statistically significant, positive correlation with radon levels. Measurement is the key to identifying the problem. Radon detection kits are available in most hardware stores.

Short-term testing (lasting a few days to several months) is the quickest way to determine if a potential problem exists. Charcoal canisters, charcoal liquid scintillation detectors, electret ion detectors, alpha-track detectors, and continuous monitors are currently the most common short-term testing devices. Short-term testing should be conducted in the lowest inhabited area of the home, with the doors and windows shut.

❑ The most common methods of radon measurement are charcoal canisters, charcoal liquid scintillation detectors, electret ion detectors, alpha-track detectors, and continuous monitors.

Long-term testing (lasting up to 1 year) will give a better reading of a home’s year-round average radon level than will a short-term test. Alpha-track detectors and electret ion detectors are the most common long-term testing devices. Exposed devices are sent via mail to a certified laboratory for analysis. These devices measure radon gas levels, rather than radon progeny; thus, the units reported are in picocuries of radon per liter of air (pCi/L).

The charcoal canister is a small can containing charcoal and a filter to keep out radon progeny. It is inexpensive ($10 to $25) and is generally used for short-term testing (3 to 7 days). The alpha-track device contains a small piece of plastic in a filtered container. As the radon gas that has entered the container decays, the alpha particles form etch tracks. These tracks can be counted using a special technique. The cost of the alpha-track device is roughly twice that of the charcoal canister, and it may be used to measure cumulative exposure over a longer period (several weeks to a year).

Radon Abatement

❑ The cost of remediation to reduce radon levels in the average home is about $1200.

❑ Available procedures to lower indoor radon levels are, dollar for dollar, very effective in saving lives.

❑ Subslab depressurization is one of the most effective methods of lowering radon levels in many homes.

How cost-effective is radon mitigation compared to other investments in health protection? The Swedish government plans to spend approximately $1000 per home reducing high radon levels, resulting in about $10,000 of cost per life spared. EPA estimates that the cost of remediation in most homes is less than $1500. The cost of radon testing and mitigation per life saved compares favorably with that of other government programs.

If excessive levels of indoor radon are found in a structure, low-cost, quick-fix methods should be implemented first. These include limiting the amount of time spent in contaminated areas and increasing ventilation. It is wise to consult with the state radiation protection office before implementing major abatement projects. Methods of reduction can be obtained from several sources listed in the Suggested Reading List and in the Sources of Information section.

Besides increasing ventilation, radon control measures include sealing the foundation, subslab depressurization (creating negative pressure in the soil), pressurizing the home, and using air-cleaning devices. Methods of increasing ventilation include opening windows, ventilating basements and crawl spaces, ventilating sumpholes and floor drains to the outside of the house, and increasing air movement with ceiling fans. Ventilation must be modified properly, however, since increased ventilation can depressurize the house in some cases, causing an increase of soil gas entry to the home. Heat exchangers provide away of bringing fresh air indoors without major heat loss, but these must be properly balanced or they can make the problem worse.

Preventing soil gas entry is more important than increasing whole-house ventilation. The former involves sealing the foundation and depressurizing the soil. Using vapor barriers around the foundation, sealing cracks and holes with epoxies and caulks, and sealing the crawl space from the rest of the house are all methods with some application. Subslab depressurization can reduce radon levels by as much as 99%. Suction puts the soil at a lower pressure than the inside of the home, preventing inward migration of soil gas. It involves sinking ventilation pipes below the foundation and continuously pumping out air ( Figure 3 ). The cost to install subslab depressurization in an existing home is approximately $1000 to $2500 and about $100 annually for utility costs. The state radon office can be consulted to obtain a listing of radon mitigation contractors that have passed EPA’s Radon Contractor Proficiency (RCP) program (see page 17). If the equipment is installed during construction of the home, however, the cost of subslab depressurization is considerably less; it is much easier to install pipes during construction than to retrofit later. Physicians and other health professionals can perform a public service by becoming acquainted with local building codes and urging local jurisdictions to include the installation of capped pipes terminating in a space under the foundation to allow for later subslab depressurization if it is needed.

Figure 3 . Subslab depressurization

Standards and Regulations

❑ Currently, there are no enforceable regulations to control indoor radon levels, only guidelines and a national goal.

❑ The national goal is for indoor radon levels to be as low as those outdoors. About 0.4 pCi/L of radon is normally found in outside air.

Currently, no regulations mandate specific radon levels for indoor residential and school environments. There are only guidelines for remediation, such as the EPA recommendations and a national goal. EPA based its guidelines not only on risk considerations, but also on technical feasibility. There is thought to be no level at which the risk of exposure to alpha emitters is zero. An EPA drinking water standard is being developed. Many standards and guidelines for radon are currently being reviewed ( Table 1 ), and changes may occur over time. EPA or state health departments should therefore be consulted for the most up-to-date standards.

Table 1 . Standards and regulations for radon

In October 1988, the Indoor Radon Abatement Act was passed. This Act states that the “national long-term goal of the United States with respect to radon levels in buildings is that the air within buildings in the United States should be as free of radon as the ambient air outside of buildings.” The Act mandates that EPA update its publication, A Citizen’s Guide to Radon, and provide a series of action levels indicating the health risk associated with these various levels. The Guide will also provide information on the risk to sensitive populations, testing methods, and the cost and feasibility of mitigation techniques. Currently, EPA recommends remediation for homes and other buildings with levels above 4 pCi/L, with the caveat that corrective action be taken below this level on a case-by-case basis.

Sources of Information

More information on the adverse effects of radon and the treatment and management of radon-exposed persons can be obtained from ATSDR, your state and local health departments, and university medical centers. Physicians and other health professionals may obtain materials from EPA for display. The federal EPA maintains an Office of Radiation Programs, 401 M Street SW, Washington, DC 20640, telephone (202) 260–9600.

Case Studies in Environmental Medicine: Radon Toxicity is one of a series. For other publications in this series, please use the order form on the back cover. For clinical inquiries, contact ATSDR, Division of Health Education, Office of the Director, at (404) 639–6204.

State Radon Contacts

Congress has mandated that each state set up an office to deal with requests for assistance.

(800) 582–1866

(800) 478–4845

(602) 255–4845

(501) 661–2301

(800) 745–7236

(800) 846–3986

CONNECTICUT

(203) 566–3122

(800) 554–4636

DISTRICT OF COLUMBIA

(202) 727–5728

(800) 543–8279

(800) 745–0037

(808) 586–4700

(800) 445–8647

(800) 325–1245

(800) 272–9723

(800) 383–5992

(913) 296–1560

(502) 564–3700

(800) 256–2494

(800) 232–0842

(800) 872–3666

MASSACHUSETTS

(413) 586–7525

(517) 335–8190

(800) 798–9050

MISSISSIPPI

(800) 626–7739

(800) 669–7236

(406) 444–3671

(800) 334–9491

(702) 687–5394

NEW HAMPSHIRE

(800) 852–3345 x4674

(800) 648–0394

(505) 827–4300

(800) 458–1158

NORTH CAROLINA

(919) 571–4141

NORTH DAKOTA

(701) 221–5188

(800) 523–4439

(405) 271–5221

(503) 731–4014

PENNSYLVANIA

(800) 237–2366

PUERTO RICO

(809) 767–3563

RHODE ISLAND

(401) 277–2438

SOUTH CAROLINA

(800) 768–0362

SOUTH DAKOTA

(605) 773–3351

(800) 232–1139

(512) 834–6688

(801) 538–6734

(800) 640–0601

(800) 468–0138

(800) 323–9727

WEST VIRGINIA

(800) 922–1255

(608) 267–4795

(800) 458–5847

Answers to Pretest and Challenge Questions

The Pretest questions are on page 1.

The differential diagnosis for the patient’s radiographic solitary pulmonary nodule would include

primary pulmonary malignancy

metastatic malignancy

granulomatous disease (for example, tuberculosis, coccidioidomycosis, histoplasmosis, nocardiosis)

AV malformation

pulmonary hamartoma

bronchial adenoma

pulmonary abscess

pseudonodule (e.g., nipple shadow, superficial skin lesion)

sarcoidosis

The following factors increase the likelihood of her having a pulmonary malignancy: radiographic appearance of the lesion (size and lack of calcification), age, symptoms of cough and weight loss, hypercalcemia, absence of residence in or travel to an area endemic for coccidioidomycosis (southwest United States) or histoplasmosis (Ohio/Mississippi Valley), absence of fever or evidence of infectious disease, and negative PPD skin test. The latter does not rule out tuberculosis but makes it less likely.

Initially, one or more of the following might be ordered:

search for previous chest radiographs for comparison

sputum studies for cytology and cultures (standard pathogens, fungus, acid-fast bacilli)

fiber-optic bronchoscopy with bronchial brushings and specimens for cytology and culture

Additional tests would follow, depending on results of these initial studies. If a primary lung cancer is detected, a metastatic workup (scans of the brain, liver, adrenals, and bones) may be indicated.

Environmental causes of lung cancer include

chloromethyl ethers

ionizing radiation (alpha, beta, gamma, or X-radiation)

polynuclear aromatic hydrocarbons (PAHs)

tobacco smoke

The treatment issues for this patient are beyond the scope of this monograph, and treatment would not be recommended until further studies are completed. The patient should be referred to an oncologist and chest surgeon (if she is a surgical candidate) for evaluation before treatment. Depending on histologic type, local extension into adjacent anatomical structures, presence of metastases, and the general health of the patient, treatment options would include surgical excision, radiation, chemotherapy, and possibly immunotherapy.

Challenge questions begin on page 4.

In addition to building location, the factors that influence radon gas entry into a home are

type and condition of the foundation

pressure differences between the soil and the inside of the home

building materials used

air exchange rate or ventilation

Anyone who spends a significant amount of time in the home would be at risk. Data are inadequate to assess individual susceptibility to radon-induced lung cancer; however, possible reasons to be additionally concerned about members of this family include that the patient’s daughter is a smoker, her grandson is still a child, and her husband has a past history of shipyard work with possible asbestos exposure. The amount of time spent at home by each family member should be considered. You might be concerned about her husband because exposures to both asbestos and radon may increase his risk of lung cancer significantly. Because he is retired, he may spend more time at home indoors, thus increasing his duration of exposure to radon.

No. Everyone in the community will not be exposed to the same radon level. Regional geologic differences such as granite deposits and soil structure are major determinants of indoor radon concentration; however, local variations can be great. Even assuming all homes in the community are built on the same geologic formation, the radon level in each home cannot be predicted. The only way to determine a home’s radon level is to test. The construction and condition of each house and the source of water supply may vary. Even if the neighbors were exposed to the same radon levels, they would not be at equal risk of health effects. The risk of lung cancer to each occupant does not depend only on the radon level, but also on the occupants themselves and their lifestyles.

The actions of radon and cigarette smoke are probably synergistic. For your patient’s daughter, who is a smoker, the risk of dying from lung cancer is 10 to 20 times greater than if she did not smoke. It is presently unknown how passive exposure to cigarette smoke affects the risk of developing lung cancer in relation to radon exposure.

No, it is unlikely that the fetus would be affected by airborne radon because alpha emitters act locally on the respiratory tract, and there are no firmly established systemic effects.

It is unlikely that radon would play any role in the development of mesothelioma because this is a malignancy of the pleural lining, not the lung. The risk for mesothelioma among asbestos workers is also not increased by smoking.

The test kit should be placed in the lowest lived-in level of the home (for example, the basement if it is frequently used, otherwise the first floor). It should be put in a room that is used regularly (like a living room, playroom, den or bedroom) but not your kitchen or bathrooom. Place the kit at least 20 inches above the floor in a location where it won’t be disturbed—away from drafts, high heat, high humidity, and exterior walls.

As a health professional, you can (a) motivate all smokers to quit smoking; (b) educate and act as a resource to patients regarding radon risks; (c) help families rank the risks of the many environmental pollutants they encounter; (d) refer the family to the health department, state radon office, or EPA for more information and relate to others your experiences in testing your own home; (e) encourage detection and mitigation of radon when indicated, and encourage appropriate building techniques for new construction.

There are currently no enforceable regulations to control indoor radon levels; therefore, there is no legal recourse. EPA recommends mitigation if the radon level indoors is above 4 pCi/L; the national goal is to reduce indoor radon levels to outdoor levels, about 0.4 pCi/L. Clearly the school’s classrooms exceed these levels. Education and persuasion of the citizenry are methods that may motivate the community to take remedial action.

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Case Studies in Environmental Medicine (CSEM)

Environmental health and medicine education, radon toxicity.

Table of Contents
How to Use This Course
Initial Check
What is Radon?
Where Is Radon Found?
What are the Routes of Exposure to Radon?
Who Is at Risk of Radon Exposure?
Standards and Regulations
Potential Health Effects
Clinically Assess a Patient
How Should Patients Be Treated and Managed?
Instructions Given to Patients
Sources of Additional Information
Assessment and Posttest
Literature Cited
Tables and Figures
Annex I: Methods of Detection and Mitigation
Patient Education and Care Instruction Sheet

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Radon Toxicity What are the Routes of Exposure to Radon?

Course : CB/WB1585 CE Original Date : June 1, 2010 CE Renewal Date : June 1, 2012 CE Expiration Date : June 1, 2014 Download Printer-Friendly version [PDF - 809 KB]

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Health Effects of Radon

Author: Kristopher Kohut

This case study is part of a collection of pages developed by students in the 2012 introductory-level Geology and Human Health course in the Department of Earth Sciences, Montana State University. Learn more about this project .

Introduction to Radon

Radon is a naturally occurring chemical element and is number 86 on the periodic table. Radon found in your home and the environment comes in the form of a gas. It is odorless, colorless and tasteless. Radon's dangerous nature comes from its radioactivity. Radon emits alpha particles which can be damaging to human tissues. In nature radon is produced by the radioactive decay of the elements uranium and thorium. Radon radioactively decays itself and has a relatively short half life. Radon produces other radioactive elements as products of its decay. These decay products, or "radon daughters" as they are commonly referred to, are dangerous as well.

Sources of Radon

Radon is produced naturally by chemical processes originating from local geology. As stated earlier radon is naturally produced by the radioactive decay of the elements uranium and thorium found within the soils and rocks of the Earth. Natural geologic sources of uranium include uranium ores and rocks of various types such as shales, granites, metamorphic rocks such as gneiss and schist, and less commonly in sandstone. Granites and shales are noted as more common sources due to their higher comparative levels of uranium in their composition. However, not all rocks of these types are prone to high levels of radon emission. So don't swear off granite counter tops, just get them tested first.

Geography of Radon

Radon is found in almost all soils around the world. These concentrations, however, are generally of low amounts. In the United States there are areas of high levels of radon. These areas reflects the type of bedrock underlying the country. Areas of higher radon levels are indicative of certain rock types in the bedrock mentioned previously as common sources of radon. The Northern states show overall higher levels than other states from the Eastern seaboard throughout the Midwest.

Natural Transportation of Radon

Radon, as a gas, flows freely in the environment. As radon is produced by minerals and certain rocks it is introduced into the soils and air around those sources. Despite its high density for a gas radon permeates upward through the soil. This is the point where radon can start to come in contact with humans. As radon moves upward through the soil it can enter a pathway to humans one of two ways. Radon can either permeate into underground water wells. Radon can also, and more commonly, rise upward into the foundation of homes and buildings. Radon can easily travel through cracks and faults in foundations which allow it to enter buildings. Once in a building radon, being dense, generally stays in the lowest level.

Bioavailability

Due to radon's gaseous state the gas mostly enters the body through inhalation. The radon gas can be directly inhaled and so can the "radon daughter" elements radon produces. These daughter elements are solids unlike radon itself. The solid elements often bind themselves to dust particles in the air allowing inhalation of these elements to take place. The airborne particles and the gas itself, when inhaled, are deposited within the lungs. Ingestion of radon through contaminated water also occurs, however it has not been found to affect human health. Contaminated water can, under certain temperatures and pressures, release radon as a gas. This occurs most often during showers.

Impacts on Human Health

Due to radon's radioactivity it is a mutagen. This means that when radon enters the body the body is now exposed to constant radiation. Radon enters the body through inhaltion and settles in the lungs. These radon molecules constantly emit alpha particles. These particles bombard the tissues of the lungs and can physically damage the DNA of the affected cells. This most notably manifest itself as lung cancer. According to the United Nation's World Health Organization radon is the second leading cause of lung cancer after smoking in many countries.

Prevention, Detection and Remediation

Prevention methods for radon are relatively simple. While not completely stopping radon entry, sealing cracks in the foundation, sealing seams in basement walls and floor, and sealing utility junctions as much as possible can greatly reduce the amount of radon that can freely enter your house. Installing ventilation for your basement can also reduce the amount of radon that is able to accumulate in your home. There are multiple options for testing for radon in your home. Acitvated charcoal kits are a simple, at home, option to test for radon. The charcoal acts as an absorber of free particles. This charcoal can be later sent in and tested for radon. Other tests aim to detect the alpha particles emmitted by radon. Most remediation techniques are designed around ventilation. There are two common ventilation options to remediate high levels of radon. One is simple mechanical ventilation of the room/level of the builiding to remove excess build up and prevent it from happenning again. Another option is what is callled active soil depressurization. In this method a pipe is lead from beneath the foundation, up through the building and terminates in an exhaust fan at the top of the building. This process alleviates air pressure under the foundation to lmit the amount of radon freely flowing upward. The fan at the terminus of the system also facilitates mechanized ventilation.

Radon—The Element of Risk. The Impact of Radon Exposure on Human Health

Anna grzywa-celińska.

1 Chair and Department of Pneumonology, Oncology and Allergology, Medical University of Lublin, 20-090 Lublin, Poland; moc.liamg@39kada

Adam Krusiński

Jadwiga mazur.

2 Institute of Nuclear Physics, Polish Academy of Sciences, 31-342 Krakow, Poland; [email protected] (J.M.); [email protected] (K.K.)

Katarzyna Szewczyk

3 Chair and Department of Pharmaceutical Botany, Medical University of Lublin, 20-093 Lublin, Poland; [email protected]

Krzysztof Kozak

Lung cancer is a heterogeneous group of diseases with multifactorial aetiology. Smoking has been undeniably recognized as the main aetiological factor in lung cancer, but it should be emphasized that it is not the only factor. It is worth noting that a number of nonsmokers also develop this disease. Radon exposure is the second greatest risk factor for lung cancer among smokers—after smoking—and the first one for nonsmokers. The knowledge about this element amongst specialist oncologists and pulmonologists seems to be very superficial. We discuss the impact of radon on human health, with particular emphasis on respiratory diseases, including lung cancer. A better understanding of the problem will increase the chance of reducing the impact of radon exposure on public health and may contribute to more effective prevention of a number of lung diseases.

1. Introduction

While many known factors contribute to carcinogenesis, the tumorigenic process is usually the result of a combination of genetic and environmental factors. The effects of some of them are modifiable, while the exposure to others is barely manageable. The harmful effects of tobacco smoke, environmental pollution, poor diet, abnormal weight and low physical activity are commonly known. Other factors are yet to be thoroughly recognized, and therefore the measures to eliminate them are less common.

The purpose of our work is to draw attention to environmental exposure to radon as an aetiological factor in respiratory diseases, including lung cancer, especially in nonsmokers.

This review answers several important questions about the impact of radon exposure on human health. It brings up a topic of partially modifiable risk factor of lung cancer, exposure to radon, which is the second largest risk factor of lung cancer for smokers and first in nonsmokers.

2. Chemical Properties of Radon

Radon is an odorless and colorless noble gas. There are four known natural isotopes including the most stable and also the isotope most significant to health, Rn-222. Its radioactivity is a characteristic feature of this element. Radon comes from the uranium decay chain (U-238), arising directly from radium decay (Ra-226). Radon decays into further radioactive elements, up to a stable lead isotope Pb-206. Its half-life is only 3.82 days. It is worth emphasizing that among radon decay products are also alpha and beta radioactive isotopes. When combined with dust and aerosol particles present in the air, they can be aspired and deposited in the human respiratory system where they decay and become a source of significant radiological exposure [ 1 , 2 ]. Radon derivatives do not deposit evenly in the respiratory system: the depth of penetration of a particle depends on its size.

Alpha (α) particles are made up of two protons and two neutrons, so they have the structure of helium nuclei. They ionize and damage the DNA found in the cells of living organisms. This radiation has a very small range and is blocked by human skin, but it can be a carcinogen if it enters the body, e.g., the respiratory tract as radon can be easily inhaled. Beta (β) and gamma (γ) radiation penetrate deeper into the body and can also cause damage to genetic material, leading to the development of a malignant tumor [ 3 , 4 ].

Radon is a noble gas and is generally chemically inactive. It is quite mobile and can migrate both in the Earth’s crust and in the air. Radon concentrations are measured in becquerels per cubic meter of air. One becquerel (1 Bq) is one disintegration per second, which is a very small unit, so units such as the curie (Ci) are used; 1 Ci is 37 GBq. For example, the activity of one gram of Rn-222 equals 1.538 × 10 5 Ci [ 5 ]. The dose of ionizing radiation absorbed by the body is expressed in Gy (gray) units and one gray is the energy of one joule absorbed by one kilogram of body weight (J/kg). The assessment of the actual effect of radiation on the human body requires the use of doses equivalent which account for the type of organ and the type of radiation. The lungs, stomach and bone marrow have a weight ratio of 0.12, and the skin ratio is 0.01. The multiplier for α radiation is 20, and that of electrons and photons is only 1 [ 6 ]. The unit of dose equivalent is the sievert (Sv), which, like the gray, is a joule of absorbed energy per kilogram of body weight. A 1 J/kg dose poses a threat to human health [ 7 ].

3. Natural Sources of Radon

Radon is responsible for approximately 40% of radiation to which humans are exposed [ 4 ] and is the main source of natural radiation [ 8 , 9 ]. It comes primarily from the soil, building materials, water and natural gas [ 10 , 11 , 12 ].

The source of radon in the air is the Earth’s crust, which contains the direct predecessor of radon in the radioactive chain, i.e., radium (Ra-226), whose decay leads to the formation of radon (Rn-222). Radon from the decay of radium in geological formations is transported to the Earth’s surface as a result of diffusion and convection. The amount of radon exhalation (extraction) depends on the location (soil type, soil geology) and atmospheric conditions (pressure, wind strength and direction, humidity, snow cover, etc.). The extent of exhalation is also closely correlated with the occurrence of tectonic faults. Such faults are an excellent path for radon migration even from deep geological layers [ 13 , 14 , 15 ].

Granite soils show high uranium content, while the content in sedimentary rocks is low. Active seismic zones, tectonic movement areas, volcanic zones and geothermal fields are significant sources of radon.

In Poland, radon occurs primarily in the Sudetes and Sudeten Foothills, where granitoid massifs and metamorphic rocks with increased uranium and thorium contents are found. The second area of the high occurrence of radon is Upper Silesia, in particular its coal-mining region. In addition to granites, large amounts of radium may contain shale and phosphate rock.

Sudeten rocks, mainly igneous, contain large amounts of uranium and radium even at low depths, reaching up to 200 m. They have a mosaic geological structure, with a lot of cracks, brittle rocks and tectonic dislocations, which make it easy for the gas to move upwards. This movement is also facilitated by flowing groundwater and carbon dioxide [ 16 , 17 ].

Radon is found in groundwater, which is associated with its flow through rocks rich in this element and showing a high emanation coefficient. In the Sudetes, the most radon is found in low-mineralized waters with a short groundwater flow period of several years. The concentration of the radioactive element reaches up to 2000 Bq/L [ 18 , 19 ]. Similarly, the content of radon in natural gas results from the fact that they occur in soil rich in elements of the uranium chain.

The concentration of radon in atmospheric air in the open is usually low. In Poland, it varies from a few to several dozen Bq/m 3 . In houses, this concentration can be much higher: from several dozen to several thousand Bq/m 3 [ 20 ].

Geographic Distribution of Radon

Data covering the 27 European countries [ 21 ] show that radon is responsible for around 8% of lung cancer deaths. In the UK, the proportion is estimated at 3.3% (0.2% of all deaths). The US Environmental Protection Agency (EPA) estimates that 1 in 15 homes in the U.S. (about seven million) have elevated radon levels [ 22 ].

The 2009 WHO report shows the arithmetic mean of indoor radon concentrations in many countries, e.g., 140 Bq/m 3 in the Czech Republic and Mexico, 49 Bq/m 3 in Poland, 46 Bq/m 3 in the USA, 28 Bq/m 3 in Canada, 20 Bq/m 3 in the UK, 16 Bq/m 3 in Japan and 11 Bq/m 3 in Australia. The global average was 39 Bq/m 3 [ 23 ].

Since 2006, research has been carried out in Europe to create an atlas with average indoor radon concentrations in rooms at ground level. In 2014, these studies were already conducted in 24 countries. The distribution of results correlates with the geological conditioning of the site. High radon concentrations were observed in the granitic areas, for example, the Bohemian Massif, the Iberian peninsula, the Massif Central, the Baltic shield, Corsica, Cornwall, the Vosges mountains, in the Central Alps, the Swiss Jura, the Dinarides, north Estonia and in volcanic parts of Italy. The arithmetic mean for Europe was 98 Bq/m 3 , and the median was 63 Bq/m 3 , but there were large differences between different countries—for example, in the Czech Republic over 90% of the country’s area had an average indoor radon concentration above 100 Bq/m 3 , while in Lithuania this percentage did not exceed 10%. For the entire examined area of Europe, the percentage of the studied area with indoor radon concentration exceeding 100 Bq/m 3 was approximately 25, and for concentrations over 300 Bq/m 3 , about 5% [ 24 ].

Research conducted in the USA shows large differences in radon levels, with the highest concentrations in the Northeast and Upper Midwest. The highest radon concentrations were recorded in Pennsylvania (844 Bq/m 3 ), and the lowest in Florida, Louisiana and California (11.1 Bq/m 3 ) [ 25 ].

4. Radon in Buildings

Radon escaping from the Earth’s crust and into atmospheric air can penetrate buildings. The share of radon in the air inside a statistically representative building, assuming full air exchange every hour, is as follows: the subsoil accounts for nearly 80% of the radon source, the second source is in building materials responsible for 12% of radon, and the third is atmospheric air—9.3%. Water and natural gas together account for less than 1% [ 11 , 12 ].

Radon is much heavier than air (7.6 times) and should remain in the basement layer but the foundation of the building changes this situation. Building a house requires “penetrating” the soil surface and reaching deeper layers, where radon concentrations are much higher due to the content of 226 Ra radium isotope. The basic mechanism for the entry of this gas into houses is always the pressure difference between the inside and the outside—the pressure inside is a few pascals lower than outside the building. This phenomenon is caused by devices, such as those for sewage or ventilation, which work in a house and “pump out” the air. Another reason is the fact that the house has a higher temperature than outside. Warmer air is lighter and thinner, it produces less pressure and causes radon to escape from the soil and rise. Radon is also suctioned from the lower rooms and building walls ( Figure 1 ). The main ways in which radon penetrates inside buildings are leaks in the building, such as cracks and crevices of the concrete screed, structural gaps and cracks in the building, cracks in the walls which have direct contact with the ground, cracks in the walls and leaks around sewage pipes.

An external file that holds a picture, illustration, etc.
Object name is toxics-08-00120-g001.jpg

Radon pathways into buildings.

Another source of radon in houses is its escape from walls and ceilings made of materials which always contain some amount of radium. Generally, it can be stated that radon from the ground dominates on the lower floors of the building, and the higher the floor, the greater the share of radon coming from building materials used in the construction. Higher levels of radioactivity are found in industrial raw materials: fly ash, slag, phosphogypsum and concrete [ 26 ].

Another source of radon is water because radon is released from it when domestic sanitary facilities (e.g., showers, baths) are used.

The concentration of radon inside buildings shows high daily and seasonal variability. In autumn and winter, when temperatures are low outside, doors and windows remain closed most of the time and radon concentrations in rooms reach much higher values.

Research carried out in Switzerland by Kropat and coauthors identified a number of factors affecting indoor radon concentrations (IRC). Less radon was found in newer buildings. It was noted, however, that radon concentrations remained at a higher level in single-family houses as compared to flats [ 27 ]. In a single-family house, the transport of radioactive radon from the ground can reach 15 kBq/h. This is mainly through advection, which depends on the difference between the outside and inside temperatures, and the movement of air over radon-rich soil [ 28 ]. Yu et al. investigated typical Hong-Kong buildings and found that radon release from the concrete walls of older buildings was smaller [ 29 ]. However, it is worth noting that building materials are a secondary source of radiation. Research in the UK has revealed a strong correlation between radon concentration and socioeconomic status. It turned out that lower levels of radon are detected in the houses of less affluent people. Factors considered to be the causes include the inferior insulation and lower temperature prevailing in such houses. The exposure to radiation generated by radon is lower but less affluent people smoke statistically more cigarettes, which is an indisputable risk factor for lung cancer [ 30 ].

The content of radon in the interior of the house is also affected by the exchange of air with the external environment. This occurs by diffusion and convection - the latter, like advection, depends on temperature and increases with its gradient [ 28 , 31 ]. Airing the apartment facilitates those processes. It is estimated that a tilted window can reduce radon levels in an interior by up to 70% [ 32 ].

Building materials are a less important source of radiation than the soil on which the building is erected. They contain radon, which is naturally produced, much like other radioactive elements of the uranium chain, thorium chain and the K-40 potassium isotope. In addition to α radiation, building materials also emit γ radiation. Some of this radiation also enters buildings from space. In practice, building materials are assessed with the use of two activity indicators, f1 and f2 [ 33 ]. The f1 index is related to the whole body exposure to γ radiation from K-40 (potassium), Ra-226 (rad), Th-228 (thorium) and should not exceed 1.2. The f2 index denotes the content of Ra-226, thus indirectly Rn-222 and its α radiation, and should be max. 240 Bq/kg. Cement and autoclaved aerated sand concrete have low f1 and f2 indexes [ 34 ]. Wooden buildings usually do not have as solid foundations as brick ones, which promotes the diffusion of radon from the ground to the building.

Taking all of the above into consideration, the awareness of the varying radon content in the soil depending on the region could contribute to least partially influencing the radon concentration in houses. The next factor is the selection of building materials, the type of the building and quality of workmanship. It seems more favorable to live in a house with tight concrete foundations. In everyday practice, frequent ventilation of an apartment remains the most important. Unfortunately, it is not always possible due to outdoor air pollution such as smog. Moreover, some energy conservation interventions can influence the indoor radon concentration. An example of such a phenomenon is thermomodernisation of buildings which results in worsening ventilation, leading to an increase in radon concentration. In France, Czech Republic and Russia the concentration of radon after sealing the buildings increased by 1.6 times, and in England, 1.7 times [ 35 ]. The US Environmental Protection Agency (EPA) recommends that every house be tested for radon concentration [ 36 ].

5. Legal Regulations

The level of risk awareness is essential for the expansion of preventive programs. Perception of risk raises concerns and causes individuals to make proactive decisions to mitigate risks. Polish and international law to some extent regulates the exposure to radon.

Baeza et al. in their research work focused on the relationship between the architectural style of single-family houses built between the 18th and 21st centuries and the concentration of radon inside them. The old, traditional houses made mainly of wood and granite; houses from 1940–1980, which were characterized by the presence of concrete, thinner walls and modernized air conditioning systems; as well as new houses, subject to the requirements of construction law, with a predominance of cement and brick and waterproof foundations, were considered. The study showed a higher concentration of indoor radon in new and traditional renovated houses, which is probably related to their increased airtightness, reducing air exchange with the external environment. On the other hand, the current building policy tries to minimize the concentration of radon in new buildings [ 37 ]. The Italian National Institute of Health in this year’s report also emphasizes the implementation of legal solutions limiting the concentration of radon in already existing buildings [ 38 ]. Such a solution was introduced by the Norwegian authorities in 2009, with the goal of reducing the radon concentration in all buildings. The specific radon prevention measures is usually a radon membrane over the entire base area of the building in combination with a passive radon sump system, activated at indoor radon concentrations above 100 Bq/m 3 . The assumed maximum level of indoor radon was 200 Bq/m 3 [ 39 ].

The United States Environmental Protection Agency advises home buyers to either take radon measurements or verify that the home has been tested for radon, and verify that the home meets the structural conditions that protect against radon exposure. According to the EPA, a homeowner should strive to reduce radon if its concentration is 4 pCi/L or more. In such a situation, it may be helpful to use a fan or a vent pipe. It may be a good idea to hire a specialist (radon-reduction contractor). The EPA places emphasis on controlling radon concentration after every change in the apartment, when changing floors, and carrying out periodic control measurements. The EPA recommends that the water supplied to the home be tested if it comes from a private well and the indoor radon level in the air is increased, as water may be the source of radon in the air. In this case, you can use either point-of-entry or point-of-use filter systems. The target indoor radon concentration should be 2 pCi/L or less [ 40 ].

An analysis carried out in Great Britain [ 21 ] shows the economic and health benefits of reducing indoor radon concentration below 200 Bq/m 3 , especially in new homes, but also in existing ones.

The European Commission has imposed an obligation on its member states to define geographic areas with a higher risk of high levels of indoor radon (“radon prone areas”) [ 41 ].

The Centers for Disease Control and Prevention’s (CDC’s) National Comprehensive Cancer Control Program (NCCCP) emphasizes the role of education and radon control [ 22 ].

Polish regulations require periodic testing of drinking water if the concentration of radon activity in water exceeds 10 Bq/L. Exposure is considered to be low between 10 and 100 Bq/L [ 42 ]. However, it is not always possible to ensure compliance with such norms, for example, the concentration of radon tested in Jelenia Góra was elevated, which may be associated with the presence of uranium-rich rocks. It was related to estimated exposure to an annual radiation dose of 0.9 mSv from drinking water alone, which corresponds to an average concentration of 200 Bq/L [ 43 ]. Potable waters are also tested for radium and tritium [ 44 ].

Council Directive 2013/59/EURATOM of 2013 and the Atomic Law Act amended in 2019 specifies the average annual reference level of radon concentration in residential buildings and workplaces, assuming the threshold of 300 Bq/m 3 [ 6 , 45 ]. Under the Directive, Member States are obliged to plan actions to reduce exposure to radon from soil, water and building materials in buildings, apartments, workplaces and public spaces. In many countries, the norm is 200 Bq/m 3 , although even this amount can double the risk of developing lung cancer [ 4 ]. The guidelines of the International Atomic Energy Agency (IAEA) specifies the acceptable average annual radon concentrations for residential and public buildings at 300 Bq/m 3 and 1000 Bq/m 3 for workplaces [ 46 ]. In public buildings, in special cases, the average annual radon concentration may reach a maximum of 1000 Bq/m 3 [ 6 ].

Also, the ordinance of the Council of Ministers on the limit doses of ionizing radiation specifies the effective dose limits, which should not exceed 1 mSv per year for pregnant women and the general population, and 20 mSv for employees [ 47 ].

However, awareness-raising programs are also important. The key point of policies of many countries is the need for a wider coverage of residents with information about the risk of radon exposure and how to reduce it. Efforts to improve public awareness have had some success in some countries [ 48 ]. Recent studies show that low-income rural citizens are unaware of the harmful consequences of radon exposure due to lack of access to adequate information [ 49 ]. Disagreement also exists between experts and the secular cult over the severity of the risk of radon exposure. In turn, it is easier for public health authorities to encourage testing and remediation when homeowners are convinced that their property and its residents are at increased risk [ 50 ]. Radon exposure risk management should include broader prevention actions at population level, which could be expanded to maximize benefits [ 48 ].

Within the project “Radon Prevention and Remediation” (2011) of the European Union, the intercomparison of various European public awareness surveys of the risk caused by radon exposure was performed [ 48 , 51 ]. Based on these results, it can be stated that the society in countries with an established national radon strategy possesses better information about radon than in countries without such of strategy. Throughout all the polls it was perceived that radon can be harmful to health, given the harm radon is quite underestimated compared to other risks. In general, it seems that the knowledge of the possibility of taking action to measure and control radon is also positively correlated with the existence of strategies communication of established risks. General remarks from the results of the implementation of the RADPAR project are the following: risk communication increases the level of information and helps to change the behavior of the society; the information about radon must be communicated continuously; possible measures to reduce radon concentrations should be adopted to local conditions and a stakeholder approach should focus on doctors, pharmacists, home inspectors and architects [ 48 , 51 ].

The risk of radon exposure for public health is summarized in much scientific evidence to substantiate political decisions and demonstrate the need for multilevel interventions. The political strategies of the various countries provide effective recommendations of these actions. They include cost-effective measures for the population, which can be promoted by developing a national program of radon exposure control under the auspices of ministries health, and proposals, which can be applied directly to households with different income levels. The key point of these policies is the need for a wider coverage of residents with information on the risk of radon exposure and how to diminishing it. Some more recent evaluations of the control programs of radon exposure concluded that efforts to inform the population has been successful in raising awareness the public and in encouraging the testing of houses at concentrations of radon. However, it is still difficult to convince populations of the importance of radon exposure control and the obligation taking measures to mitigate the consequences of this phenomenon. Public health policy in the field of risk of exposure to radon should take into account the attitude of the government and a resident in solving this problem [ 48 , 52 , 53 ].

6. Application of Radon as a Method of Treatment

Historically, radon was part of a dangerous trend involving the use of radioactivity in medicine. In the United Kingdom, devices for adding radon to drinking water were sold, and radon compresses were used in the arthritis therapy. What is more, radioactive compounds were administered intravenously. That route of administration caused malignant tumors in patients, mainly bones [ 54 ]. The era of universal radon availability ended with the accumulation of evidence of its association with miners’ lung cancer. To this today, however, so-called radon waters have been used in spa and wellness treatments. This is due to the coexistence of two conflicting theories about the impact of radiation on human health.

The National Academy of Sciences Biologic Effects of Ionizing Radiation (BEIR VII) report, based on the available scientific evidence, supports the linear no-threshold theory (LNT), indicating a linear relationship between the radon dose and the adverse health effect [ 55 ]. Similarly, according to International Commission on Radiological Protection (ICRP), there is no dose of radon so low that it does not pose a risk of lung cancer [ 35 ]. Even the smallest dose of radiation has a carcinogenic potential if it hits the DNA of a cell and causes a genetic mutation.

In opposition to LNT, there is the radiation hormesis hypothesis, whose proponents believe that low doses of radiation are useful for health [ 56 ]. This theory is based on the validity of the use of radioactive sources in balneology, specifically in healing waters and inhalations. Radon water is categorized as specific water because it has a specific component, in this case, radon, whose concentration should not be lower than 74 Bq/L [ 57 , 58 ]. Some Polish wellness towns which use radon water include Jedlina Zdrój, Lądek Zdrój, Przerzeczyn, Szczawno Zdrój, Świeradów Zdrój, Długopole Zdrój and Duszniki Zdrój [ 59 ]. Radon baths are recommended by the Polish national consultant on balneology and physiotherapy [ 60 ].

Radon waters appear to be analgesic and anti-inflammatory and regulate the activity of the autonomic nervous system. Radon probably influences the neuroendocrine system, affecting the adrenal glands via the pituitary gland. Subsequent hormonal changes modulate T-cell function. Radon water therapy is recognized primarily by dermatologists and rheumatologists. Treatments are offered for rheumatoid arthritis, scleroderma, fibromyalgia, infectious joint diseases, neuralgia, chronic post-traumatic pain, potency disorders, menopause symptoms, endocrine disorders, sinusitis and peripheral vascular diseases. They are also recommended in the treatment of allergic diseases, such as atopic dermatitis and allergic rhinitis, as well as in lung diseases—asthma and chronic bronchitis [ 57 ]. Research indicates the effect of radon on Langerhans cells, an increase in enkephalin levels and a reduction in the amount of free oxygen radicals in phagocytes [ 61 ].

Treatments using radon media increase the synthesis of adrenal cortex hormones, as well as female and male sex hormones. Radon waters have a positive effect on the carbohydrate metabolism, increase the production of B and C vitamins. Radon also has a positive effect on the skin as an anti-inflammatory, antipruritic and analgesic, and also accelerates the regeneration process of the epidermis [ 62 ]. Radon treatments improve blood circulation and skin elasticity [ 63 ]. A one-time fifteen-minute radon bath increases blood flow through the tissues by about 400%. This congestion lasts over 60 min from the end of the bath. Treatment with radial waters has a positive effect on the parameters of lipid metabolism [ 62 ]. Radon also accelerates the regeneration of damaged nerve fibers. The likely mechanism of this action is to cause local overheating and intensify the synthesis and secretion of neurohormones. Radon therapy is also effective in the treatment of peripheral vascular diseases, however, it is recommended to use waters with high radon content, such as in the waters of Lądek Zdrój or Świeradów Zdrój in Poland [ 64 ].

Kojima et al. provided case reports of two patients with pemphigus and type I diabetes who benefited significantly from radiotherapy that employed low doses of nontargeted α-radiation and its associated β- and γ-radiations, delivered by the inhalation of radon (in a typical radon spa). Radon therapy, properly delivered, has been shown to induce important remedies that provide relief from severe suffering and the possibility of return to normal living. Moreover, the authors did not observe any side effects after this therapy [ 65 ].

Due to exposure to low doses of radiation and the potential risk of induction of carcinogenesis, from the very beginning of treatment with radon media, the question of their dosage is the most controversial. The first problem is the daily and seasonal variability of the radioactivity of natural radon sources, which decreases both during long-term precipitation and in its absence and increases with increasing atmospheric pressure. Often, the measurements of the activity of radial waters are limited to the determination of the radial activity of the healing water source itself, ignoring the changes that occur in the water during the preparation of baths or pools. Heating the radon water during the preparation of the bath reduces the solubility of radon, which depends on temperature and pressure. Heating the radon water causes an average loss of radon content of 50–70% [ 62 ].

The legitimacy of using the potentially dangerous treatment methods in the light of the availability of many other therapies with proven effectiveness remains debatable. The potential risk/benefit ratio should be carefully assessed due to the strong evidence indicating the health-threatening effects of radiation emitted by radon.

7. Impact of High Doses of Radiation on Human Health

Natural sources such as radon emit small doses of radiation. Therefore, their negative health effects do not manifest as the classic radiation sickness caused by contact with man-made high-energy radiation. Such radiation would be emitted as a result of an atomic bomb explosion or a nuclear power plant disaster. In nearly three-quarters of century since the Hiroshima and Nagasaki bombings and a quarter of a century since the explosion at the Chernobyl nuclear power plant, many studies have been carried out on the effects of high doses of radiation on living organisms [ 66 , 67 , 68 , 69 , 70 ].

Depending on the intensity of the absorbed radiation, the area of the body exposed to the radiation and the duration of exposure, the biological effects will vary. Unfortunately, in extreme situations, they can lead to immediate death. The survivors may develop various types of complications, starting from the molecular level and ending with the systemic one.

Acute radiation syndrome can occur in a person after when the dose is at least one gray (Gy), or one joule of energy per kilogram of body weight. The most sensitive element of the human body are mature lymphocytes, the number of which decreases as soon as one day after exposure. Subsequently, bone marrow is damaged. At a dose of about 5 Gy, the disease affects other organs, in particular the digestive system, followed by the skin and central nervous system. The prodromal symptoms of the acute illness include nausea, vomiting, diarrhea and abdominal pain, which can be caused by transient activation of the autonomic system. Chronic radiation sickness can develop even at doses lower than 1 Gy. It affects similar organs as the acute disease [ 7 , 71 ]. An additional long-term effect of radiation exposure is a malignant tumor. This phenomenon can occur even as a result of exposure to elevated concentrations of radon originating from natural sources.

8. Radon Is an Aetiological Factor in Cancer and Noncancerous Diseases

8.1. cancer diseases.

Radon is considered a carcinogenic agent [ 72 ]. Carcinogenesis is a multifactorial process leading to the formation of cancer. It is a long-term process that disturbs the balance between proliferation, apoptosis, differentiation and aging of cells, and its course depends on the type of tumor and the tissue in which it occurs [ 73 ]. The causes of the carcinogenesis process are hereditary and spontaneous mutations induced by chemical and physical factors. They concern genes responsible for the control of the life cycle: suppressor genes, proto-oncogenes and regulatory genes. Changes in the nucleotide sequence in the DNA chain result in uncontrolled fragmentation of the mutated cell, which leads to neoplastic transformation [ 74 ]. In studies that were carried out on an animal model, it was found that there are three basic stages in the process of carcinogenesis: initiation, promotion and progression. In the initiation stage, an irreversible change of a genotypic nature occurs, which consists in DNA damage caused by the interaction with a reactive form of a carcinogen [ 74 ]. The second phase of carcinogenesis is promotion, which is the result of the incorporation of promoting carcinogens (promoters). At the stage of promotion, epigenetic changes take place, and there is a selective clonal growth of the initiated cells by increasing proliferation or inhibiting apoptosis. As a result, phenotypic changes occur, preneoplastic damage to the mutant cell occurs, and specific functions are lost and connectivity with other cells occurs. The last stage of carcinogenesis is progression, which is an irreversible stage, including invasion of adjacent tissues and metastasis to distant organs [ 75 ]. A carcinogen is a mutagen that causes DNA damage. Depending on the nature and way of action of carcinogens, they can be divided into two groups: genotoxic and epigenetic. Genotoxic carcinogens, which bind to DNA, initiate and cause the progression of mutations necessary for tumor development. Any exposure to genotoxic carcinogens may carry a risk of inducing cancer as they are nonthreshold factors. This means that it is not possible to define a safe concentration (threshold) that does not cause any changes in the body. The genotoxic carcinogen class includes direct factors that do not require metabolic activation, and indirect factors (carcinogens) whose metabolites are direct carcinogens. Epigenetic carcinogens, which do not bind to DNA, activate proto-oncogenes as a result of disturbed signaling pathways and accelerate the process of carcinogenesis by promotion or immunosuppression [ 76 ].

The pathogenic effect of radon (and above all its decay products remaining in the respiratory system) is associated with the emission of ionizing radiation. Such radiation may, directly and indirectly, damage the genetic material contained in the cell nucleus DNA. It breaks the DNA double-strand [ 77 ]. The indirect effects are based on water radiolysis and the generation of reactive oxygen species. DNA damage causes mutations leading to cell carcinogenesis, resulting in the development of tumors. The European Code Against Cancer announced twelve principles for cancer prevention in 2015. One recommendation was to reduce exposure to high levels of radon [ 78 ]. In Europe, it is estimated that radon present in houses is responsible for 2% of deaths from malignant neoplasms [ 79 ]. The correlation of radon with the incidence of lung cancer has been proven beyond doubt, however, that this element can probably also cause kidney cancer, melanoma, as well as haematological cancers and primary brain tumors [ 80 , 81 ]. The relationship between radon and cancer of the stomach, liver and pancreas is unresolved [ 82 ], while no such correlation has been proven for throat and oral cancer [ 83 ].

Radon has little potential for penetration into systems other than the respiratory system, and therefore its association with diseases other than respiratory diseases is uncertain. There is still no scientific evidence to relation of radon to diseases other than lung cancer. The available data are conflicting even in the best-studied diseases such as leukemia. WHO suggests treating the results of such research with caution as it may be misleading [ 23 ]. Moreover, even finding a significant statistical correlation does not explain the mechanism of carcinogenesis. Taking into account the kinetics of radon, its place of action should be primarily the bronchi and lungs, and in the case of drinking water with increased content of the gas, the digestive system.

8.1.1. Occupational Radon Exposure

It is estimated that millions of people are currently working underground, and their exposure to radon is significantly higher because it is not diluted in the atmosphere. It is worth remembering that its concentration underground can be reduced through ventilation systems and radon-proof barriers [ 84 ]. Most of the research on the effects of radon on human health was carried out on miners who were exposed to higher doses of radon in their work environment than ordinary people in their place of residence. Pooled data from eleven studies conducted on miners [ 85 ] did not show a significant association between cumulative radon exposure and mortality from nonlung cancer. While there are studies showing such correlations, miners’ exposure to numerous environmental factors other than radon does not reliably link radon exposure to lung diseases other than lung cancer [ 86 ].

A statistically significant correlation was found in miners with a greater incidence of leukemia, especially chronic lymphocytic leukemia (CLL), while a positive correlation was not significant in the case of Hodgkin’s lymphoma and myeloid leukemia considered separately [ 87 ]. Colorado miners showed a higher incidence of non-Hodgkin’s lymphoma and multiple myeloma [ 82 ]. However, another study [ 88 ] conducted on a population of miners did not confirm the relationship between radon and leukemia, but showed a significant increase in mortality associated with cancer of the liver, gallbladder and extrahepatic bile ducts, but it was not possible to demonstrate a causal relationship between exposure to radon and the occurrence of these events. Similarly, a higher incidence of liver and stomach cancer was observed in miners from Kazakhstan’s uranium mines [ 53 ]. Morrison et al. found a relationship between radon and oropharyngeal cancer, but the number of cases detected was too small to be reliable [ 89 ]. In the case of miners examined in Silesia, an increase in the incidence of lung and larynx cancer was noted, and miners who came to work from another region suffered more often [ 90 ]. The relationship between radon and central nervous system (CNS) neoplasms observed in miners remains uncertain [ 91 ].

8.1.2. Indoor Radon Exposure

Initially, the results of research conducted on miners were extrapolated to other populations, which was associated with a high risk of error. The first large studies attempting to show the relationship between radon in the living environment and cancer were based mainly on average radon concentrations obtained from databases, and not measured by researchers, which limited the credibility of these studies [ 92 ]. Other environmental studies have provided inconsistent and often statistically insignificant data on the relationship of radon to hematological malignancies [ 93 , 94 ]. Many other environmental studies have been dedicated to leukemia, especially among children, but the results are contradictory.

Some ecological studies have shown a relationship between mean radon levels and childhood leukemia incidence and mortality rates [ 95 , 96 , 97 , 98 ]. Recently, a newly prediction model was used in a large nationwide Danish study to calculate indoor radon levels in the homes of children with cancer and control children. The authors found a significant relationship between cumulated radon exposure and risk for acute lymphoblastic leukemia in children [ 95 ]. Also, dosimetric calculations done in the UK have indicated that about 6% of childhood leukemia’s might be due to domestic radon [ 99 ]. Statistical associations of radon with thyroid, skin and kidney cancer have been observed, however, other overlapping causes of these diseases cannot be excluded, and therefore the relationship remains uncertain [ 91 ].

Some studies have been done on the association between skin cancer and radon. The American Cancer Prevention Study II cohort noticed hazard ratios of 1.08 (95% CI: 0.88, 1.33) and 0.70 (95% CI: 0.42, 1.19) per 100 Bq = m 3 in mean county-level residential radon for malignant melanoma and nonmelanoma skin cancer mortality, respectively [ 100 ]. Wheeler and co-authors revealed an association between radon and occurrence of squamous cell carcinoma, but not basal cell carcinoma or malignant melanoma, in southwest England. Moreover, they didn’t found an association with occurrence of nonmelanoma skin cancer at the national level [ 101 ]. In another study, the authors found a statistically significant association between basal cell carcinoma and radon, but not for malignant melanoma or squamous cell carcinoma in a Danish cohort research [ 102 ]. Vienneau et al. found an increased risk of skin cancer mortality in association with household radon levels in Switzerland. Their study supports the hypothesis that radon exposure is a relevant risk factor for skin cancer independent of residential erythemal-weighted radiation exposure. The authors found a statistically significant increased risk of death from malignant melanoma and skin cancer in general, independent of erythemal-weighted radiation, in adults associated with exposure to radon. Switzerland has amongst the highest skin cancer incidence that may be related to the wealth and behavior of the population leading to recreational UV radiation exposure. In addition, natural UV levels are also relatively high owing to the elevation in the alpine regions. Moreover, certain areas of Switzerland have elevated radon levels because of the underlying geology, which leads to high doses of radon [ 100 ].

8.2. Noncancerous Diseases

Radon can also cause noncancerous diseases and affect their course. A relationship is observed between radon exposure and chronic obstructive pulmonary disease (COPD) development and the frequency of hospitalizations, especially in women [ 103 ]. Miners exposed to radon were more likely to die from silicosis and pulmonary fibrosis, but also end-stage renal disease in diabetic nephropathy [ 82 ]. Schubauer-Berigan and coauthors found that cumulative silica exposure is related to cumulative radon exposure, because they are correlated with duration of mine employment. The authors observed a strong gradient between silicosis standardized mortality ratios and radon exposure. This finding suggests that miners with high radon exposures also had raised silica exposures, likely during early time periods when silica exposures were not controlled [ 47 ]. Alternatively, radon-related pulmonary diseases may have been misattributed as silicosis, leading to elevations in the silicosis standardized mortality ratios for the higher working level month (WLM) groups. A relationship between exposure to higher radon concentrations and the occurrence of congenital malformations such as cleft lip and palate and cystic lymphangioma has also been shown [ 104 ]. Correlation with radon exposure was also sought in patients with neurodegenerative diseases, in particular multiple sclerosis, however, studies by Groves-Kirkby et al. showed no statistically significant relationship [ 105 ].

Research conducted on the population living in the region of Kazakhstan, rich in uranium mines, showed a greater number of women with impaired fertility and children with urinary tract diseases and chronic bronchitis [ 53 ]. Seo et al. also studied a relation between radon exposure and heart disease, but research results are uncertain [ 91 ]. Blomberg and coauthors observed higher mortality due to cardiovascular and respiratory diseases with the simultaneous occurrence of increased concentrations of PM2.5 and radon. The authors indicate that PM2.5 can act as a vector for radon, transporting it to the bronchial tree [ 25 ].

It should be remembered that water is an important source of radon. Radon can pass from water to air, and in the case of drinking water, it can also reach the digestive tract. The National Research Council estimates that approximately 30% of the radon-222 reaching the stomach enters the stomach wall, suggesting its potential to cause stomach cancer [ 106 ]. Several studies have been conducted between the concentration of radon in drinking water and the occurrence of gastrointestinal malignancies, but their results are contradictory [ 107 , 108 ].

9. Radon and Lung Cancer

The special relationship of radon with lung cancer, as well as with other pulmonary diseases, results from its physicochemical properties. As a gas contained in atmospheric air, it can easily be inhaled into the bronchial tree, where it is deposited especially in bronchial bifurcations [ 109 ]. Its labile radioactive derivatives, i.e., polonium, bismuth and lead (Po-218, Pb-214, Bi-214, Po-214), reach the lungs. Po-218, which deposits in the bronchial tree and emits α and β radiation, is particularly dangerous [ 4 ]. α-radiation has a short-range and can be easily shielded, but in the lungs, it has direct access to epithelial cells and can damage genetic material. The dose dependence of radon carcinogenic potential has been demonstrated, and a marked increase in lung cancer risk has been observed at long-term exposure to 100 Bq/m 3 [ 23 , 110 ].

Vahakangas and coauthors detected mutations in the p53 protein gene in miners exposed to high doses of radon [ 111 ]. The p53 protein is coded by tumor suppressor gene TP53 localized in on chromosome 17p13.1 [ 112 ]. The p53 protein gene is the site of the most common inactivating mutations in patients with lung cancer [ 4 ]. Experimental studies of Liu et al., involving high-dose radon irradiation of bronchial epithelium, showed its effect on p53-related metabolism, particularly apoptosis and glycolysis [ 113 ]. In studies conducted by the same author on miners from a tin mine, attention was also paid to the synergistic effect of radon with arsenic in inducing bronchial epithelial mutations [ 114 ]. Experiments performed by Chen et al. on rats and human bronchial epithelial cells showed an increase in the production of reactive oxygen species, down-regulation of let-7 microRNA and an increase in the expression of the KRAS oncogene [ 4 , 115 ]. Similarly, no differences were found in the frequency of EGFR gene mutations, while ALK rearrangement was slightly more frequent at higher radon concentrations [ 116 ]. Taga et al. raised the hypothesis that the EGFR mutations can be related to residential radon or second-hand smoking. Although they observed a high frequency of EGFR mutations (41%) in lung tumors in never smokers or long-term former smokers, but no association between EGFR mutations with neither secondhand smoking nor exposure to residential radon was found [ 117 ]. On a large group of patients with non-small-cell lung cancer, Mezequita investigated the relationship between the intensity of radon exposure and the occurrence of specific types of mutations such as EGFR, BRAF, KRAS and HER2, as well as ALK and ROS1 rearrangements. It was observed that the occurrence of EGFR, BRAF, HER2 and ROS1 was significantly higher in areas with high radon exposure, while KRAS mutations were more frequent in areas with low exposure [ 118 ]. More recent research of Mezquita et al. tried to answer the question if there is any link between the genetic diversity of non-small-cell lung cancer and exposure to indoor radon, Although it was conducted in a small group of patients the research led to the conclusion that indoor radon concentrations exceeded those recommended by WHO, and despite the fact that there were no differences between groups with EGFR, ALK, and BRAF patients, the concentrations above the WHO recommendations were most common with ALK rearrangement and BRAF mutation [ 119 ].

It should be noted that EGFR mutations and ALK rearrangements offer the possibility of targeted therapy in patients with inoperable lung cancer [ 120 ]. Miners exposed to radon showed elevated levels of interleukin 6, which is secreted by pulmonary fibroblasts and may contribute to both cancer and COPD [ 121 , 122 ].

The main aetiological factor in lung cancer is smoking, which can account for up to 90% of deaths from this cancer. Lung cancer patients are often stigmatized due to the indisputable effect of smoking on lung cancer [ 123 ]. It should be emphasized, however, that lung cancer also occurs in people who have never smoked.

Work-related factors account for 9–15% of deaths and radon accounts for 10%, while the impact of air pollution is at a level of 1–2% [ 4 ]. The synergistic effect between smoking and radon is indisputable. As many as 86% of deaths from lung cancer associated with radon exposure occurred in smokers and former smokers [ 124 ]. Therefore, it seems that actions taken to discourage smoking would be more beneficial than just lowering radon levels in the human environment. However, it should not be forgotten that radon remains the second independent lung cancer risk factor after smoking, and therefore the first aetiological factor in the population of never smokers [ 4 , 23 , 121 ].

In the US, 15–21 thousand deaths a year from lung cancer are associated with radon [ 4 , 124 ]. Radon is associated with all histological types of lung cancer. It most frequently causes adenocarcinoma. It also contributes to squamous cell carcinoma [ 122 , 125 ]. It has been shown that miners in uranium (radon precursor) mines die even three times more often from lung cancer [ 4 ]. An analysis of eleven studies carried out on miners showed an increased risk of death from lung cancer per working level month (WLM), and the relationship between this risk and the cumulative dose was almost linear [ 23 ]. In one study, radon was responsible for 40% of deaths from lung cancer among miners, including 39% in smokers and 70% in never-smokers. For the sake of comparison, the value for houses was 10% of deaths, including 11% in smokers and 30% in never-smokers [ 126 ]. In the UK, 1100 deaths are reported annually from lung cancer related to exposure to indoor radon [ 21 ]. Research has shown that there is a clear relation between radon in concentrations typical for residential buildings and the risk of developing lung cancer [ 23 ].

Some studies show an additive or even hyperadditive effect of simultaneous smoking and radon exposure on the risk of lung cancer. It has been shown that, with the same radon exposure, smokers have a greater risk of developing lung cancer than nonsmokers [ 127 ]. It has been suggested that this effect occurs at high radon concentrations. A greater risk of lung cancer associated with radon exposure has been shown in nonsmokers, but the absolute risk is greater in smokers due to the predominant influence of cigarettes on carcinogenesis [ 92 , 128 ].

The research conducted on rats comparing the synergic effects of exposure on radon and other airborne pollutants, for example, tobacco smoke, beta-naphthoflavone, mineral fibers and diesel exhausts. The strongest link was shown between the combined effect of radon and tobacco smoke and the incidence of lung cancer. This effect decreased as exposure to tobacco smoke was limited [ 129 ].

A similar effect was also shown in humans. In the matched case-control study conducted in Korea it was proved that exposure to residential radon and smoking had a synergistic effect increasing the risk of developing lung cancer [ 130 ].

10. Conclusions

In the light of modern knowledge, the relationship between lung cancer and radon exposure remains undeniable. It is known that radon is the second most common cause of lung cancer in smokers and the most common one in nonsmokers. Even though WHO deemed radon exposure as carcinogenic, knowledge about this threat remains incomplete and superficial. The need to inform the medical professionals and the public about the carcinogenic effect of radon exposure has been indicated by the work of American authors who conducted a systemic review of 20 studies on public understanding of the impact of radon exposure on lung cancer development [ 131 ]. It has been shown that even in a group of people confirming that they have heard of radon, only slightly more than 20% are aware of the relationship between radon and lung cancer. Even in the group of people who conducted radon tests at home, only 50% have such understanding. This work also drew attention to the problem of misunderstanding the issue of radon exposure and mistaking the symptoms associated with radon exposure for symptoms corresponding to carbon monoxide poisoning.

Our article is part of the process of popularizing the issue of radon exposure and its carcinogenic effect.

This research received no external funding.

Conflicts of Interest

The authors declare no conflict of interest.

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

R. WILLIAM FIELD, PhD, MS, University of Iowa College of Public Health, Iowa City, Iowa

Am Fam Physician. 2018;98(5):280-282

Author disclosure: No relevant financial affiliations.

Protracted exposure to radon decay products is the leading environmental cause of cancer mortality in the United States. 1 , 2 Family physicians play a key role in informing their patients about the health risks posed by radon exposure and in recommending proactive actions to reduce radon exposure.

How Does Radon Enter a Home?

Radon, with a radioactive half-life of 3.8 days, is a tasteless, colorless, and odorless radioactive noble gas formed from the radioactive decay of radium, a globally occurring natural component of soil and bedrock. Radon naturally occurs outdoors, but it is generally found at higher concentrations indoors because most houses are not built to be radon resistant. Building ventilation and stack effects cause lower air pressure in a house as compared with the air pressure in the soil around the foundation and basement slab. This pressure differential draws radon into the house through floor-wall joints, cracks in the foundation, and other openings in the building's substructure. Radon released from well water and building materials (e.g., concrete) also represents a potential secondary source of radon in a house.

Elevated residential radon concentrations are found in all types of houses in every U.S. state, regardless of the age of the home or the socioeconomic status of the neighborhood. Therefore, the U.S. Environmental Protection Agency (EPA) recommends that all houses be tested for radon and that action be taken to reduce radon concentrations that are equal to or exceed the EPA's radon action level of 4 pCi per L (150 Bq per m 3 ). 3 The EPA also suggests lowering the radon concentrations to less than 4 pCi per L to further reduce lung cancer risk because there is no safe level of radon. 3

Radon testing is inexpensive ($15 to $25) and can easily be completed using do-it-yourself radon test kits, which are available at most hardware stores or by calling 800-SOS-RADON (800-767-7236). If elevated radon concentrations are detected, radon mitigation costs generally range from $800 to $1,500 and are eligible health savings account or flexible spending account expenses.

Additional information about radon testing and mitigation is provided in the EPA's Citizen's Guide to Radon 3 and other EPA publications ( https://www.epa.gov/radon ). In collaboration with the EPA, the Conference of Radiation Control Program Directors (a nonprofit organization) also recently released a new Radon Guide for Health Care Providers 2 that provides clinicians with guidance to help their patients reduce exposure to radon ( http://canceriowa.org/BreathingEasier.aspx ).

What Is the Evidence of Radon's Carcinogenicity?

Overwhelming evidence of radon's carcinogenicity comes from 11 large epidemiologic studies of underground miners exposed to radon and from the 1999 National Research Council's pooled analysis of those studies. 4 , 5 In addition, pooled analyses of residential radon studies performed in China, Europe, and North America have also demonstrated that protracted exposure to radon (and radon decay products), even below the EPA's action level, significantly increases lung cancer risk. 6 – 8 The National Research Council's lung cancer risk projections to the general public from protracted radon exposure closely agree with the risk estimates reported from these three pooled analyses. 1 , 2 , 5 Based on the National Research Council's findings from the pooled underground miner studies 4 and further supported by the findings of the residential radon case-control studies, 6 – 8 the EPA estimates that 21,000 people die from radon-induced lung cancer each year in the United States, which represents about 13% of annual U.S. lung cancer deaths. 9 If treated as an individual disease category, radon-induced lung cancer would rank among the top 10 causes of cancer mortality. 2 The combined health effects of radon and tobacco exposure are synergistic rather than additive, so reducing either of the exposures substantially reduces lung cancer risk. 2 , 5 Table 1 presents the lifetime risk of lung cancer death from radon exposure in homes based on smoking status and radon level. 2

How Does Radon Induce Lung Cancer?

Radon decays into a series of solid radioactive products that can be inhaled and then deposited onto the pulmonary epithelium. Two of the alpha-emitting decay products, polonium-214 and polonium-218, deliver the majority of the radiogenic dose to the lungs and have been identified as the primary cause of radon-induced lung cancer. 2 – 5 These decay products cause single- and double-strand DNA breaks as well as indirect genotoxic and nongenotoxic effects on cells, which can lead to malignancy. 2 , 4 , 5

Does Radon Present a Substantial Risk to Individuals Who Have Never Smoked?

In the United States, up to 20% of lung cancer deaths each year occur in individuals who have never smoked, which translates to about 30,000 Americans in 2017. 10 Protracted radon exposure is considered the leading cause of lung cancer in this population. 1 – 5

Is a History of High Radon Exposure An Eligible Criterion for Low-Dose CT Screening?

The U.S. Preventive Services Task Force states that the benefit of low-dose computed tomography (CT) screening varies because individuals who are at higher risk of developing lung cancer because of smoking history and other risk factors, such as high radon exposure, are more likely to benefit than individuals who have no risk factors. 11 Furthermore, the National Comprehensive Cancer Network guidelines recommend low-dose CT screening beginning at 50 years of age for individuals with at least a 20 pack-year smoking history and documented high radon exposure. 12 Interviews to assess eligibility for low-dose CT screening present an opportunity to educate patients about the risks posed by smoking and radon exposure, even if the individual is not eligible for low-dose CT screening. It is important to note that the American Academy of Family Physicians concludes that the evidence is insufficient to recommend for or against screening for lung cancer with low-dose CT in persons at high risk based on age and smoking history. 13

Field RW, Withers BL. Occupational and environmental causes of lung cancer. Clin Chest Med. 2012;33(4):681-703.

Conference of Radiation Control Program Directors. Reducing the risk from radon: information and interventions. A guide for health care providers. http://www.radonleaders.org/sites/default/files/HealthCareProfessionalsGuide_Radon_2018_FINAL_CRCPD%20E-18-2.pdf . Accessed June 27, 2018.

U.S. Environmental Protection Agency. A citizen's guide to radon: the guide to protecting yourself and your family from radon. https://www.epa.gov/sites/production/files/2016-12/documents/2016_a_citizens_guide_to_radon.pdf . Accessed June 28, 2018.

National Research Council. Health Effects of Exposure to Radon: BEIR VI . Washington, DC: The National Academies Press; 1999. https://www.nap.edu/read/5499/chapter/1 . Accessed June 28, 2018.

World Health Organization. WHO handbook on indoor radon: a public health perspective. http://apps.who.int/iris/bitstream/10665/44149/1/9789241547673_eng.pdf . Accessed June 28, 2018.

Lubin JH, Wang ZY, Boice JD, et al. Risk of lung cancer and residential radon in China: pooled results of two studies. Int J Cancer. 2004;109(1):132-137.

Darby S, Hill D, Auvinen A, et al. Radon in homes and risk of lung cancer: collaborative analysis of individual data from 13 European case-control studies. BMJ. 2005;330(7485):223.

Krewski D, Lubin JH, Zielinski JM, et al. Residential radon and risk of lung cancer: a combined analysis of 7 North American case-control studies. Epidemiology. 2005;16(2):137-145.

U.S. Environmental Protection Agency. EPA assessment of risks from radon in homes. https://www.epa.gov/sites/production/files/2015-05/documents/402-r-03-003.pdf . Accessed June 28, 2018.

Simon S. Lung cancer risks for non-smokers. November 6, 2017. American Cancer Society. https://www.cancer.org/latest-news/why-lung-cancer-strikes-nonsmokers.html . Accessed June 28, 2018.

Moyer VA. Screening for lung cancer: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2014;160(5):330-338.

National Comprehensive Cancer Network. NCCN quick guide: lung cancer screening. https://www.nccn.org/patients/guidelines/quick_guides/lung_screening/files/assets/basic-html/page-1.html# . Accessed June 28, 2018.

American Academy of Family Physicians. Clinical preventive service recommendation: lung cancer. https://www.aafp.org/patient-care/clinical-recommendations/all/lung-cancer.html . Accessed June 28, 2018.

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After smoking, residential radon is the second risk factor of lung cancer in general population and the first in never-smokers. Previous studies have analyzed radon attributable lung cancer mortality for some countries. We aim to identify, summarize, and critically analyze the available data regarding the mortality burden of lung cancer due to radon, performing a quality assessment of the papers included, and comparing the results from different countries. We performed a systematic scoping review using the main biomedical databases. We included original studies with attributable mortality data related to radon exposure. We selected studies according to specific inclusion and exclusion criteria. PRISMA 2020 methodology and PRISMA Extension for Scoping Reviews requirements were followed. Data were abstracted using a standardized data sheet and a tailored scale was used to assess quality. We selected 24 studies describing radon attributable mortality derived from 14 different countries. Overall, 13 studies used risk models based on cohorts of miners, 8 used risks from residential radon case-control studies and 3 used both risk model options. Radon geometric mean concentration ranged from 11 to 83 Becquerels per cubic meter (Bq/m 3 ) and the population attributable fraction (PAF) ranged from 0.2 to 26%. Studies performed in radon prone areas obtained the highest attributable mortality. High-quality publications reported PAF ranging from 3 to 12% for residential risk sources and from 7 to 25% for miner risk sources. Radon PAF for lung cancer mortality varies widely between studies. A large part of the variation is due to differences in the risk source used and the conceptual description of radon exposure assumed. A common methodology should be described and used from now on to improve the communication of these results.

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This research was funded by Instituto de Salud Carlos III grants ISCIIII/PI21/01081 and ISCIII/PI19/01081 co-funded by the European Union.

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Lucia Martin-Gisbert, Alberto Ruano-Ravina, Leonor Varela-Lema, Marina Penabad, Alexandra Giraldo-Osorio, Cristina Candal-Pedreira, Julia Rey-Brandariz, Nerea Mourino & Mónica Pérez-Ríos

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LM-G has participated in the formal analysis, investigation, methodology, writing of the individual draft and visualization. AR-R has participated in the conceptualization, methodology, supervision, writing-review & editing and visualization. LV-L performed formal analysis, investigation, methodology, supervision, project administration and writing-review & editing. MP has participated in the conception, investigation, methodology, writing-review & editing. AG-O has participated in the conception, investigation, methodology, writing-review & editing. CC-P has participated in the conception, investigation, and writing-review & editing. JR-B has participated in the conception, investigation, and writing-review & editing. NM has participated in the conception, investigation, and writing-review & editing. MP-R has participated in the conceptualization, formal analysis, investigation, methodology, supervision, project administration, writing-review & editing and visualization.

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Martin-Gisbert, L., Ruano-Ravina, A., Varela-Lema, L. et al. Lung cancer mortality attributable to residential radon: a systematic scoping review. J Expo Sci Environ Epidemiol 33 , 368–376 (2023). https://doi.org/10.1038/s41370-022-00506-w

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DOI : https://doi.org/10.1038/s41370-022-00506-w

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Indoor radon: a case study in risk communication

Affiliation.

1 Radon Division, U.S. Environmental Protection Agency, Washington, DC 20460.
PMID: 7917448

Two key questions have influenced the development and implementation of the Environmental Protection Agency (EPA) program to reduce the public health risks of indoor radon gas; the answers may also apply to other preventive health care programs. First, how can we best communicate risk? Risk communication research indicates that simple message, persuasion, and prescriptive guidance will best encourage citizens to protect themselves from voluntary risks (within the control of the individual), such as radon. However, scientists expect technical information, logical and unemotional appeals, and detailed explanations of uncertainty. An appropriate balance between the persuasive and the technical will encourage public action and assuage the scientific community. Second, what environmental health care problems should we focus on? Public concern with involuntary risks imposed by an external force, such as hazardous waste dumps, drive our environmental health agenda. Consequently, because government decision-makers respond to public perceptions and pressures, which they frequently support, the largest fraction of the government's resources and the most aggressive protection programs are typically reserved for environmental health problems that pose involuntary risks. The experience of the EPA's Radon Program suggests that major gains in public health protection could be achieved through communication that effectively persuades people to accept personal responsibility for preventing voluntary risks, such as radon, and a more informed dialogue between the scientific community and the public concerning national priorities for environmental health protection.(ABSTRACT TRUNCATED AT 250 WORDS)

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Comparative Study
Air Pollution, Indoor / adverse effects*
Air Pollution, Radioactive / adverse effects*
Communication*
Environmental Health
Preventive Medicine
Radon / adverse effects*
United States
United States Environmental Protection Agency

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Case Study: The Lung Cancer Mystery Mark as Favorite (34 Favorites)

ACTIVITY in Radiation , Alpha/Beta/Gamma Decay , Radioactive Isotopes . Last updated January 29, 2024.

In this activity, students will analyze a scenario about the sudden spike of lung cancer cases in a specific neighborhood. They will take on the role of an investigative reporter in order to examine important information related to the crisis. The activity will provide students the opportunity to learn about radon gas, radiation, and radioactive isotopes. The activity will culminate with the creation of a poster in the form of a public service announcement, where students will focus on the decay of radon and bring awareness to the hazardous radiation that is emitted.

Grade Level

High School

NGSS Alignment

This activity will help prepare your students to meet the performance expectations in the following standards:

HS-PS1-8: Develop models to illustrate the changes in the composition of the nucleus of the atom and the energy released during the processes of fission, fusion, and radioactive decay.
Asking Questions and Defining Problems
Engaging in Argument from Evidence
Obtaining, Evaluating, and Communicating Information

By the end of this activity, students should be able to:

Describe one of the three main types of nuclear radiation, alpha radiation.
Evaluate textual and graphic evidence to support that energy released in the process of nuclear decay may result in the incidence of cancer in human patients.
Identify the composition of the nucleus before and after nuclear decay.
Identify the emitted particles resulting from nuclear decay.

Chemistry Topics

This activity supports students’ understanding of:

Nuclear Chemistry
Radioactive Isotopes

Teacher Preparation : 10-20 minutes Lesson : 120 minutes

A copy of student handouts (printed or digital)
Poster Paper
Poster-making materials like paper, pencils, coloring markers
No special safety considerations are needed.

Teacher Notes

Students should work in groups of 3-4 to answer the case study. Within the group, students will pick jobs: reader, ambassador, investigator and writer. The duties of each are outlined in the supplemental PowerPoint presentation.
The timing for each task is suggested on the PowerPoint presentation. This is editable, and you can change the suggested times for tasks as you see fit.
Students should be provided with part 1 of the case study first. It contains four links for the students to research the causes of lung cancer, so you may want to consider providing an electronic copy as well.
Case study is based on the original case study for medical students found in: Environmental Medicine: Integrating a Missing Element into Medical Education, 1995 – Case #50 .
When students are done with the tasks and work from part 1, they are provided with part 2. I suggest that while each student should have their own copy (this could be in electronic form), each group can turn in one completed case study by the end of a 60-minute class period.
The public service announcement poster activity is important for students to make a model of the nuclear decay of radon. I suggest this is done individually, but you student can work in pairs as you see fit.
The poster portion of the activity can be omitted if time does not allow for it.
While not ideal, the case study could be used as a substitute lesson plan with some modification and assigned as an individual activity.

For The Student

It was 1982 when Mr. and Mrs. Jones moved into their new home. They had 2 children and lived a relatively healthy and active life, except that Mr. Jones had been an avid smoker for many years. He quit smoking after 20 years. They resided in California and lived through an earthquake in 1994 of a magnitude of 6.7. In 1999 Mrs. Jones was diagnosed with lung cancer and died in 2000. Mr. Jones decided to quit smoking when his wife was diagnosed. Neither of the children ever smoked. Mr. Jones went to the doctor because he had a cough for 3 months that would not go away, even after taking cough medicine. He also lost 20 pounds.

Mrs. Perez moved to the same neighborhood 3 years before. Around the time Mr. Jones went to the doctor, Mrs. Perez who never smoked, found that she was also losing weight and had a cough that would not go away. Both Mr. Jones and Mrs. Perez were eventually diagnosed with lung cancer. Over the next 2 years their neighborhood had 20 total cases of lung cancer. Is this a coincidence?

Websites for research

American Cancer Society:
https://www.cancer.org/cancer/lung-cancer/causes-risks-prevention/what-causes.html
Mayo Clinic:
https://www.mayoclinic.org/diseases-conditions/lung-cancer/symptoms-causes/syc-20374620
John Hopkins Medicine:
https://www.hopkinsmedicine.org/health/conditions-and-diseases/lung-cancer/lung-cancer-risk-factors
American Lung Association:
https://www.lung.org/lung-health-diseases/lung-disease-lookup/lung-cancer/learn-about-lung-cancer/what-is-lung-cancer/what-causes-lung-cancer
What are some causes of lung cancer? Mention at least 3 different causes.
Imagine you are a reporter for the local newspaper. Write down 3 key details about this medical mystery that a reporter would need to investigate.
Imagine you are a reporter for the local newspaper. Mr. Jones, his children and Mrs. Perez have all agreed to be interviewed by the media. Which patient will you interview, and why?
Write down 3 questions you would ask the patient.

Mrs. Perez joined an online lung cancer support group. They had a lot of links that explain the many causes of lung cancer. She found an article about radon. With this new knowledge, she tested her house and found that the average amount of Radon in her home was above recommended levels. She started to urge neighbors and the community in general to be tested for Radon. The U.S. Environmental Protection Agency (EPA) recommends that homes need inspection and repair to lower the amount of radon if the measured level is 4 pCi/L or higher. pCi refers to picocuries . According to the EPA each year about 14,000 deaths in the United States are due to lung cancer caused by indoor radon exposure.

Background Information

Summary : Large quantities of isotope Radon-222 inside homes is the main cause of exposure to ionizing radiation in most of the world. This type of radiation is emitted by radioactive isotopes, like Rn-222, and has enough energy to remove electrons from atoms. The removal of electrons from atoms results in the production of ions. Ionizing radiation cannot be seen or smelled. However, it can be detected with specialized instruments like a Geiger counter or a film badge, usually worn by X-ray technicians. Exposure to radon gas does not cause immediate irritation and for this reason there are no obvious signs of discomfort in patients until symptoms appear. Symptoms include a cough that will not go away for months and weight loss. In addition, not everyone in a home is affected the same way by Radon-222 and some people may not develop symptoms, or may develop symptoms at different times. The only way to know if a home is contaminated with Rn-222 is to test and measure radon levels in homes.

What is Radon? Radon is a gas with no detectable color or smell. The main source of radon in homes is soil, but sometimes the source can be building materials or underground water. Radon can concentrate inside a home in a few different ways. It can diffuse into a home through cracks, dirt floors or cinder block walls. While in the open air, radon gas will cause little risk. But inside a home, radon gas can become concentrated because of how airflow is regulated when homes have temperature controlled systems, exhaust fans, dryers, fire places, and other appliances that affect how air moves.

Radon gas is the result of the radioactive decay of radium, an element that is often found in rock and soil. Radon’s half-life is 3.8 days. While this is a relatively short time, it is enough time for the gas particles to move through the soil and building materials and concentrate inside homes. The gas is then inhaled by people living inside the home. Radon-222 can undergo radioactive decay inside the respiratory system, expose the patients to alpha radiation and result in the incidence of lung cancer. The decay of radon produces four isotopes with half-lives of less than 30 minutes.

Alpha Radiation : Alpha radiation (⍺), is a type of radioactive emission characterized by a Helium nuclei. It contains two protons, two neutrons and a net positive charge of +2. When an alpha particle is released it can penetrate 0.05 mm into body tissue. With constant exposure this particle can eventually result in cellular damage. Here is an example of the emission of alpha radiation:

Are other members in the homes of the patients at risk for lung cancer as a result of elevated radon levels?
What are 4 main topics that you need to research to understand how Radon’s radioactive decay causes lung cancer?

Instructions

In your group, assign one topic (from question 2 above) to each group member. Set a timer for 10 minutes. Each member must research their own topic and find 2-3 important/noteworthy details. Record the information from each group member in the table below.

Radon Mystery Poster

You will create a public health announcement that must include a model of the decay of Radon.

Using an 8x10 sheet of paper create a poster to serve as a public health service announcement.
Radon’s half-life and decay reaction
Explain all parts of the decay reaction
What type of radiation is emitted from radon decay
Ways we can identify radon contamination in our homes
The consequences of radon contamination in a home
Symptoms of lung cancer

IMAGES

Quiz & Worksheet
Assessment and Mitigation of Indoor Radon Problem: A Case Book for
why buildings have high radon
What every homeowner should know about radon
Case Study 38: Radon Toxicity
The 5 W's (and 1 H) Every Homeowner Should Know About Radon Testing

VIDEO

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The Opportunities and Risks of RRNC
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IMPLEMENTING THE CYCLE OF SUCCESS A CASE STUDY ANSWER KEY

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PDF ATSDR Case Studies in Environmental Medicine Radon Toxicity
Radon is a radioactive element. Two of its isotopes (radon-220 and radon-222) are progeny in two decay chains that begin with naturally occurring thorium and uranium, respectively, in rock, soil, water, and air. Because radon is a noble gas, it is colorless, odorless, tasteless, and imperceptible to the senses.
In the radon case study
discussion post on radon case study in four parts in the radon case study, it was concluded that there was need for policy that would be useful to tenants and. Skip to document. University; ... A national radon effort—led jointly by the federal government and key national partners—will fundamentally change home builder, buyer and owner ...
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Radon is a radioactive element. Two of its isotopes (radon 220 and radon-222) are progeny in two decay chains that begin with naturally occurring thorium and uranium, respectively, in rock, soil, water, and air. • Because radon is a noble gas, it is colorless, odorless, tasteless, and imperceptible to the senses.
Case Study 2.0 Radon SO Student Edition Updated 3.1.21.pdf
Case Study 2.0: Radon by Chris Kling Section Editor: Jay Herrigel Introduction Radon gas is a byproduct of the underground decay of the radioactive element radium, which is found in uranium and thorium ores. As these radium deteriorates, radon gas is released and eventually works its way to the surface of the ground and into the air we breathe. This radioactive gas can leach through the soil ...
Case Study 38: Radon Toxicity
Radon gas is derived from the radioactive decay of radium, a ubiquitous element found in rock and soil. The decay series begins with uranium-238 and goes through four intermediates to form radium-226, which has a half-life of 1600 years.
Health effects of radon
Generally, these associations has been confirmed in a high-quality case-control or cohort study, either in radon-exposed miners or in the general population, although several such studies have been carried out (Laurier et al. 2001, Möhner et al. 2006). As with the studies of radon exposure and lung cancer, these ecological studies are prone to ...
Radon Toxicity Case Study: What are the Routes of Exposure to Radon
This educational case study document is one in a series of self-instructional modules designed to increase the primary care provider's knowledge of hazardous substances in the environment and to promote the adoption of ... Key Points: For the U.S. general public, radon is second only to medical radiation as the principal ionizing-radiation ...
Radon Toxicity: Cover Page
Key Concepts. The U. S. Environmental Protection Agency estimates that indoor radon exposure may result in 21,000 lung cancer deaths annually in the United States. Radon may be second only to smoking as a cause of lung cancer. Increased use of medical radiation also contributes to the annual radiation dose. The combination of smoking and radon ...
Health Effects of Radon
This means that when radon enters the body the body is now exposed to constant radiation. Radon enters the body through inhaltion and settles in the lungs. These radon molecules constantly emit alpha particles. These particles bombard the tissues of the lungs and can physically damage the DNA of the affected cells.
Indoor Radon: A Case Study in Risk Communication
Two key questions have influenced the development and implementation of the Environmental Protection Agency (EPA) program to reduce the public health risks of indoor radon gas; the answers may also apply to other preventive health care programs. First, how can we best communicate risk? Risk communication research indicates that simple message, persuasion, and prescriptive guidance will best ...
Radon—The Element of Risk. The Impact of Radon Exposure on Human Health
3. Natural Sources of Radon. Radon is responsible for approximately 40% of radiation to which humans are exposed [] and is the main source of natural radiation [8,9].It comes primarily from the soil, building materials, water and natural gas [10,11,12].The source of radon in the air is the Earth's crust, which contains the direct predecessor of radon in the radioactive chain, i.e., radium ...
Atmosphere
People are mainly exposed to radon in their homes and workplaces. Radon is a serious health risk, and the second most prevalent cause of lung cancer after tobacco smoking [].Radon exposure may contribute to approximately 21,800 lung cancer deaths annually in the United States [].Some case-control studies of residential radon in North America showed a direct association between prolonged ...
Radon: A Leading Environmental Cause of Lung Cancer
Protracted exposure to radon decay products is the leading environmental cause of cancer mortality in the United States. 1, 2 Family physicians play a key role in informing their patients about ...
Indoor Radon: A Case Study in Risk Communication
Indoor Radon: A Case Study in Risk Communication Stephen D. Page, MPA Two key questions have influenced the development and implementation of the Environmental Protection Agency (EPA) program to reduce the public health risks of indoor radon gas; the answers may also apply to other preventive health care programs.
PDF Teacher™s Guide to Indoor Air Quality
When Class Begins: 1. Explain to students the importance of good air quality in your classroom and why schools present a unique indoor air quality situation. 2. Ask children to use their knowledge of sources of indoor air pollutants in the home to point out possible sources of indoor air pollutants in the classroom.
Radon
Radon is a naturally occurring radioactive gas which may be found in high concentrations in indoor environments, such as homes and workplaces. Radon is one of the leading causes of lung cancer. Radon is estimated to cause between 3% to 14% of all lung cancers in a country, depending on the national average radon level and smoking prevalence.
Lung cancer mortality attributable to residential radon: a systematic
That is the case of Canada, as first study published on 2005 used a very low radon exposure from a 1978 national radon survey available at that time and latter studies used more complete radon ...
Indoor Radon: A Case Study in Risk Communication
Results: The overall prevalence of residential radon testing among respondents was 18%, 2- to 6-fold higher than any estimate of residential radon testing in the general population. The strongest relationship with radon testing observed through logistic regression was with marital status; age, ethnicity, and region of residence were also related.
PDF Radon Testing and Home Sales
Radon Testing and Home Sales A Case Study In 2015, Montgomery County, Maryland became the first jurisdiction in the nation to pass a law requiring that homes for sale be tested for radon, an invisible odorless radioactive gas that causes lung cancer. ... The American Lung Association sought to answer two questions: 1. Was there any significant ...
Indoor radon: a case study in risk communication
Risk communication research indicates that simple message, persuasion, and prescriptive guidance will best encourage citizens to protect themselves from voluntary risks (within the control of the individual), such as radon. However, scientists expect technical information, logical and unemotional appeals, and detailed explanations of uncertainty.
Classroom Resources
Students should work in groups of 3-4 to answer the case study. Within the group, students will pick jobs: reader, ambassador, investigator and writer. The duties of each are outlined in the supplemental PowerPoint presentation. The timing for each task is suggested on the PowerPoint presentation.
ATSDR Clinician Brief: Radon
Radon is a chemically and biologically inert noble gas produced when naturally occurring uranium and thorium undergo radioactive decay. Radon undergoes further radioactive decay into daughters (progeny) until reaching a stable form of lead. Two isotopes of radon (radon-220 and radon-222) are the daughters in two decay chains that begin with ...
Unfolding Case Study (by rmdaquin) Flashcards
Study with Quizlet and memorize flashcards containing terms like PART 1: Jason, a 12-year-old boy, has been sick for the last 3 days with flulike symptoms: pallor, fatigue, loss of appetite, muscle aches, and a 101° F to 102° F fever. His parents have been giving him over-the-counter cough and cold medications as well as Tylenol to control his fever. His parents take him to his pediatrician ...