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Radon
More Dangerous In Air Than In Water
Experts are well aware
of the risks of breathing radon gas, but what about
water-borne radon?
The National Research
Council asked this same question recently and concluded
that radon in drinking water poses few risks to humans by itself.
But it can increase one’s overall risk when the gases are released
in the air and are inhaled.
Radon, an odorless,
colorless, tasteless gas formed from the breakdown of
subsurface uranium, disperses quickly when exposed to open air. As
radon decays, it produces damaging particles that stick to dust and
smoke that are inhaled, causing cell damage to the lungs that
ultimately may lead to cancer.
Of the more than 160,000
people who die from lung cancer each year, it’s believed 19,000 of
these deaths stem from a combination of smoking and exposure to
radon. Exposure to 4pCi/l of radon over a 24 hour period is equal to
two cigarettes a day. However, there is only a comparatively small
risk associated with inhaling escaped radon from water. Of the
19,000 lung cancer deaths associated with smoking and radon
exposure, it’s believed only 160 of these deaths stem from water.
Radon exposure normally
is associated with seepage of the gas from the soil into
unventilated areas such as crawlspaces and basements.
Waterborne radon would
be especially risky in homes where soil-borne radon emissions are
near or exceed the action level of 4 picocuries per litter. A common
source of such exposure is from showers, where radon vaporizes from
the water, increasing the concentration of air in the home.
While waterborne radon
has been detected in at least one public drinking water supply in
Alabama, it is not considered a serious problem in Alabama, says Dr.
Harry Strawn, Alabama Cooperative Extension System program
coordinator.
The most likely threat
stemming from radon exposure from water is stomach cancer. But even
this number is small: the Council estimates only about 20 of the
13,000 stomach-cancer deaths occurring in the United States each
year can be attributed to exposure to radon-contaminated water.
While most water
supplies in the United States don’t contain enough radon to pose
a serious health risk, the Environmental Protection Agency set a
standard for radon in drinking water in 1991 not to exceed 300
picocuries per liter.
The agency estimates
that only 1 in 14 Americans routinely consumed water with radon
concentrations exceeding the maximum levels established by EPA. Of
more than 60,000 water systems each serving 25 customers or more,
27,000 were estimated to be above the proposed standards.
To receive more
information on radon or radon testing,
please contact Dr. Harry Strawn, Extension Radon Program director,
at (334) 844-3688, or Susan Roberts, assistant director, at (334)
844-3686.
In Madison County,
contact Sabrina Lyle, Extension radon education technician, at the
Madison County Extension office at (256) 532-1578, Ext. 11.
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