SPEAK NOW REGARDING USEPA's RADON IN WATER PROPOSAL
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Speak Now Regarding USEPA’s Radon Proposal 1/3/2000 By Frederick W. Pontius,
P.E. On November 2, 1999, the US Environmental Protection Agency (US EPA) published
the proposed regulation for radon in drinking water. Reviewing the 132-page
federal register notice, plus hundreds of pages of supporting documents packed
full of technical detail, is a formidable task. If radon is new to you, brace
yourself. Complex technical, policy, and ethical issues await.
Radon Facts Radon is a naturally occurring radioactive gas formed from the
decay of uranium-238. It decays, emitting ionizing radiation in the form of
alpha particles. Inhalation of radon and its decay products causes lung cancer;
it enters indoor air primarily from the soil under homes. Tap water is a small
source of radon in air. Ingestion of radon in drinking water presents a small
risk of stomach cancer.
Radon in drinking water contributes a very small fraction of the total lung
and stomach cancers in the U.S. About 160,000 people—mostly smokers—die
from lung cancer each year. Some 19,000 of these deaths are attributable to
combined effect of indoor radon and smoking. Of those, USEPA estimates that
about 150 deaths result from inhaling radon that is emitted from household water.
Ingesting radon in drinking water is estimated to cause 18 of the 14,000 stomach
cancers each year.
Smoking plays an important role by compounding the health risk. Smoking cessation
programs could achieve greater reductions in terms of lung cancer. Nevertheless,
radon in drinking water is thought to pose a significant risk when compared
to other drinking water contaminants.
The proposed rule applies only to Community Water Systems (CWSs). A non-enforceable
health goal of zero is proposed for radon. The proposed enforceable standard,
or maximum contaminant level (MCL) is 300 pCi/L. At this concentration, there
is a statistical probability of two people in 10,000 contracting cancer after
a lifetime of exposure.
The best available treatment for radon is high performance air stripping. High
performance air stripping, granular activated carbon (GAC) and point-of-entry
GAC are proposed as Small Systems Compliance Technologies. Construction of air
stripping towers may be difficult in certain areas because of siting issues
(‘not in my backyard’) and strict permit limits.
An estimated 39% of community groundwater systems have radon greater than 300
pCi/L. Estimated national compliance cost for treatment is $408 million/year
at 300 pCi/L. Surface water systems are not expected to exceed the proposed
Setting the Maximum Contaminant Level Flexibility is allowed under the Safe
Drinking Water Act (SDWA) for US EPA to consider other sources of radon when
setting the MCL. The agency considers the feasible level for treating radon
in drinking water to be 100 pCi/L. The costs and benefits of control programs
for radon in soil gas compelled the agency to propose the drinking water MCL
at a less stringent level.
An Alternative MCL (AMCL) is proposed at 4,000 pCi/L, which would apply instead
of the MCL if a state or utility has a multimedia mitigation (MMM) program to
lower indoor air radon. The AMCL is based on the national average outdoor radon
level of 0.04 pCi/L.
Multimedia Mitigation Programs MMM programs must meet four criteria. First,
the public must be involved in MMM program development. Second, quantitative
goals must be set for existing homes remediated and new homes built radon-resistant.
Third, strategies are identified for achieving goals. Lastly, results are tracked
CWSs in states that have an MMM program need only meet the AMCL. In states
without an MMM program, the utility can develop their own MMM program and comply
with the AMCL. But local utility-run programs will be challenging. State MMM
programs make sense, but require commitment of resources in times of tight state
Treatment and MMM program implementation costs range from $60 million to $121
million/year, depending upon the number of states implementing MMM. Only 0.8%
of community groundwater systems exceed 4000 pCi/L. The cost of water treatment
for these systems is $43 million/year.
USEPA must finalize the radon rule by August 6, 2000. Public comments on the
proposal are required by January 3, 2000. A copy of the proposed rule, fact
sheets, and instructions on submitting comments may be obtained from USEPA’s
radon web page, http://www.epa.gov/safewater/radon/proposal.html.
To be useful to the agency, public comments must thoughtfully address a spectrum
of complex issues. But time is very short—perhaps too short. With three
major holidays (Thanksgiving, Christmas, and New Years) during the comment period,
and uncertainties regarding the affects of Y2K, extra effort will be needed
to meet the public comment deadline.
About the Author: Frederick W. Pontius, P.E., is a consultant in Lakewood,
Colorado, specializing in drinking water regulatory affairs and compliance,
and strategic planning. Fred has 20+ years in the water and wastewater industries.
He is a frequent conference and seminar speaker, was a former staffer with the
American Water Works Association from 1982 to 1999, and is a contributing editor
to the Journal of the American Water Works Association (since 1991). This is
his first monthly column for Water Online, which will appear monthly as the
“Getting the Inside Edge with Fred Pontius.” He may be reached at
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