July 1999 |
ToxFAQs™ |
for |
Radon |
(Radón) |
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This fact sheet answers the most frequently
asked health questions about radon. For more information,
you may call the ATSDR Information Center at 1-888-422-8737.
This fact sheet is one in a series of summaries about hazardous
substances and their health effects. This information is important
because this substance may harm you. The effects of exposure
to any hazardous substance depend on the dose, the duration,
how you are exposed, personal traits and habits, and whether
other chemicals are present.
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HIGHLIGHTS: Radon is an odorless,
radioactive gas formed from the breakdown of uranium.
Exposure to high levels results in an increased risk of
lung cancer. This chemical has been found in at least
5 of the 1,177 National Priorities List sites identified
by the Environmental Protection Agency (EPA). |
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What
is radon? |
Radon is a naturally occurring radioactive
gas that is odorless and tasteless. It is formed from the
radioactive decay of uranium. Uranium is found in small amounts
in most rocks and soil. It slowly breaks down to other products
such as radium, which breaks down to radon.
Radon also undergoes radioactive decay.
It divides into two parts-one part is called radiation, and
the other part is called a daughter. The daughter, like radon,
is not stable, and it also divides into radiation and another
daughter. The dividing of daughters continues until a stable,
nonradioactive daughter is formed. During the decay process,
alpha, beta, and gamma radiation are released. Alpha particles
can travel only a short distance and cannot travel through
your skin. Beta particles can penetrate through your skin,
but they cannot go all the way through your body. Gamma radiation
can go all the way through your body.
Radon is no longer used in the treatment
of various diseases including cancer, arthritis, diabetes,
and ulcers. Radon is used to predict earthquakes, in the study
of atmospheric transport, and in exploration for petroleum
and uranium.
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What
happens to radon when it enters the environment? |
- Radon enters the environment from the soil, from uranium
and phosphate mines, and from coal combustion.
- Radon has a radioactive half-life of about 4 days; this
means that one-half of a given amount of radon will decay
to other products every 4 days.
- Some of the radon produced in the soil will move to the
surface and enter the air.
- Radon daughters attach to dust and other particles in
the air.
- Most of the radon will remain in the soil.
- Radon also moves from the soil and enters the groundwater.
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How
might I be exposed to radon? |
- Radon is found at very low levels in outdoor air.
- It is found at higher levels in indoor air in homes, schools,
and office buildings.
- Cracks in the basement or foundation of a home may allow
higher levels of radon inside the home.
- Indoor radon levels are affected by the radium and uranium
levels in soil, the porosity of the soil, the composition
and condition of the foundation materials, and the ventilation
rate of the room.
- Miners, particularly those who mine uranium and hard rock,
are exposed to higher levels of radon.
- Radon is found in drinking water and may be higher in
well water.
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How
can radon affect my health? |
Exposure to high levels of radon may
result in an increased incidence of lung diseases, such as
emphysema and pulmonary fibrosis. These diseases have been
seen at a higher rate than normal among underground miners
who were also exposed to arsenic, silica dust, diesel fumes,
and cigarette smoke. Lung disease has been reported to increase
with increasing exposure to radon and cigarette smoking.
Effects on the lung have also been seen
in animals exposed to radon.
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How
likely is radon to cause cancer? |
People exposed to high levels of radon
have an increased incidence of lung cancer.
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Is
there a medical test to show whether I've been exposed to radon? |
Radon in human tissues is not detectable
by routine medical testing. However, several of its decay
products can be detected in urine and in lung and bone tissue.
These tests cannot tell how much radon you were exposed to,
nor can they be used to predict whether you will develop harmful
health effects.
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Has the federal government made recommendations to protect human health? |
The EPA has set a guideline for radon
in air inside homes of 4 picocuries per liter (4 pCi/L) of
air.
The EPA has also set a standard of 20
picocuries per square meter per second (20 pCi/m²/sec)
for emissions of radon-222 (a radon daughter) to the air from
uranium mill tailings in non-operational piles.
The federal recommendations have been
updated as of July 1999.
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Glossary |
CAS: Chemical Abstracts Service.
Emphysema: A lung disease.
Millirem (mrem): A unit used to measure
radiation dose.
National Priorities List: A list of the
nation's worst hazardous waste sites.
Picocurie (pCi): A unit used to measure
the quantity of radioactive material.
Pulmonary fibrosis: Formation of fibrous
tissue in the lung.
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References |
Agency for Toxic Substances and Disease
Registry (ATSDR). 1990. Toxicological Profile for radon. Atlanta, GA: U.S. Department of Health
and Human Services, Public Health Service.
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Where can I get more information? |
ATSDR can tell you where to find occupational
and environmental health clinics. Their specialists can recognize,
evaluate, and treat illnesses resulting from exposure to hazardous
substances. You can also contact your community or state health
or environmental quality department if you have any more questions
or concerns. For more information, contact:
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Agency for Toxic Substances and Disease Registry
Division of Toxicology
1600 Clifton Road NE, Mailstop F-32
Atlanta, GA 30333
Phone: 1-888-42-ATSDR (1-888-422-8737)
FAX: (770)-488-4178
Email: ATSDRIC@cdc.gov
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