Radon in Drinking Water
Radon is a naturally-occurring radioactive gas that may
cause cancer, and may be found in drinking water and indoor air. Some
people who are exposed to radon in drinking water may have increased risk
of getting cancer over the course of their lifetime, especially lung
cancer. Radon in soil under homes is the biggest source of radon in indoor
air, and presents a greater risk of lung cancer than radon in drinking
water. As required by the Safe Drinking Water Act, EPA has developed a
proposed regulation to reduce radon in drinking water that has a
multimedia mitigation option to reduce radon in indoor air.
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Reference:
"Radon," Ground Water & Drinking Water.
U.S. Environmental Protection Agency. July 5, 2004.
<http://www.epa.gov/safewater/radon.html>.
Radon and Drinking Water from Private Wells
What is
radon?
Radon is a radioactive gas. It occurs naturally and is produced by the
breakdown of uranium in soil, rock, and water. It can also dissolve into
our water supply.
How can I
be exposed to radon?
Radon typically moves up from the ground to the air and into your home
through cracks in the foundation. Radon gas can also enter the home
through well water. As you shower or use your well water for other
household tasks, the gas can be released from the water into the air.
Where and
how does radon get into drinking water?
While most radon-related deaths are due to radon gas accumulated in houses
from seepage through cracks in the foundation, 30 to 1,800 deaths per year
are attributed to radon from household water. Showering, washing dishes,
and laundering can disturb the water and release radon gas into the air
you breathe.
What are the
symptoms of radon exposure?
Drinking water that has high levels of radon may be a health risk, but
breathing air high in radon concentration is more harmful to your health.
Breathing in radon gas over a long period of time can increase your risk
of getting lung cancer. Drinking water contaminated by radon may increase
your chances of developing stomach cancer.
What should I
do if I have concerns about radon exposure?
See your health care provider to discuss your concerns.
How is radon
exposure diagnosed?
Before you test your water for radon, you should test the air. If the
indoor radon level is high and you use groundwater, test your water. If
the radon level is low in the air, there is no need to test your water.
Test results are expressed in picocuries of radon per liter of water (pCi/l).
In general, 10,000 pCi/l of radon in water contributes roughly 1 pCi/l of
airborne radon throughout the house. The U.S. Environmental Protection
Agency (EPA) currently advises consumers to take action if the total
household air level is above 4 pCi/l.
What is
the treatment for radon exposure?
For waterborne radon, a simple step is to make sure your bathroom, laundry
room, and kitchen are well ventilated. If your well water only has
moderate levels of radon, this may adequately reduce your exposure to
waterborne radon. However, if your well has high levels of radon, you may
need to use water treatment devices such as granular activated carbon (GAC)
units and home aerators.
How do I
remove radon from my drinking water?
Radon can be removed from water by using one of two methods:
-
Aeration treatment—spraying water or mixing it with
air and then venting the air from the water before use, or
-
GAC treatment—filtering water through carbon. Radon
attaches to the carbon and leaves the water free of radon. Disposing the
carbon may require special handling if it is used at a high radon level
or if it has been used for a long time.
In either treatment, it is important to treat the water
where it enters your home (point-of-entry device) so that all the water
will be treated. Point-of-use devices such as those installed on a tap or
under the sink will only treat a small portion of your water and are not
effective in reducing radon in your water. It is important to maintain
home water treatment units properly because failure to do so can lead to
other water contamination problems. Some homeowners use a service
contract from the installer to provide carbon replacement and general
system maintenance.
Revised Summer
2003
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Reference:
"Radon
and Drinking Water from Private Wells,"
Drinking Water. Division of Parasitic Diseases. Centers for Disease and
Control Prevention. July 5, 2004.
<http://www.cdc.gov/ncidod/dpd/healthywater/factsheets/radon.htm>. |
