New Drinking Water Standard for Arsenic
The Environmental Protection Agency (EPA) has
finalized a regulation to reduce the public health risks from arsenic in
drinking water. The Agency is revising the current drinking water standard for
arsenic from 50 parts per billion (ppb) to 10 ppb. This revision will provide
additional protection for 13 million Americans against cancer and other health
problems, including cardiovascular disease and diabetes, as well as neurological
Studies have linked long-term exposure to
arsenic in drinking water to cancer of the bladder, lungs, skin, kidney, nasal
passages, liver, and prostate. Non-cancer effects of ingesting arsenic include
cardiovascular, pulmonary, immunological, neurological, and endocrine (e.g.,
Short-term exposure to high doses of arsenic
can cause other adverse health effects, but such effects are unlikely to occur
from U.S. public water supplies that are in compliance with the existing arsenic
standard of 50 ppb.
The current standard of 50 ppb was set by EPA
in 1975, based on a Public Health Service standard originally established in
1942. A March 1999 report by the National Academy of Sciences concluded that the
current standard does not achieve EPA's goal of protecting public health and
should be lowered as soon as possible.
On June 22, 2000, EPA proposed a new drinking
water standard of 5 ppb for arsenic and requested comment on options of 3 ppb,
10 ppb, and 20 ppb. EPA evaluated over 6,500 pages of comments from 1,100
responses. Under the Safe Drinking Water Act Amendments of 1996, EPA was
required to issue a final rule by January 1, 2001 and Congress subsequently
extended this date to June 22, 2001. On
January 22, 2001 the official version of the final rule was published in the
Federal Register. The final rule can be found on the Internet at www.epa.gov/safewater/ars/arsenic_finalrule.html
The Safe Drinking Water Act, as amended in 1996, requires EPA to revise the existing drinking water standard for arsenic. The new standard will protect against possible adverse health effects from exposure to this contaminant and will reflect the statutory evaluation of whether the costs are justified by the benefits. The process for revising the standard is complex, and EPA must consider a range of scientific, economic, and programmatic factors.
In 1996, Congress established certain requirements EPA must meet in designating a new standard for arsenic. These requirements have shaped the agency's strategic approach. EPA will use peer-reviewed health effects research to meet the statutory deadlines, along with studies of treatment, analytical methods, occurrence, and cost-benefits, and will identify affordable small system technologies. Results of focused long-term arsenic research efforts will be considered in future reviews of the Maximum Contamination Level (MCL), which will be evaluated at least every six years, as appropriate, as required by the 1996 amendments.
The Safe Drinking Water Act requires EPA to set the MCL as close to a public health goal as feasible, taking into consideration treatment technology and regulatory costs and benefits. For the new standard, EPA must identify affordable small system technologies.
Currently, the arsenic MCL only applies to community water supplies, such as those supplying houses, apartments, mobile home parks, and condominiums. The new MCL would also apply to non-transient non-community systems, such as those supplying schools and office buildings.
The new standard will apply to all 54,000 community water systems. A community water system is a system that serves 15 locations or 25 residents year-round, including most cities and towns, apartments, and mobile home parks with their own water supplies. EPA estimates that roughly five percent, or 3,000, of community water systems, serving 11 million people, will have to take corrective action to lower the current levels of arsenic in their drinking water.
The new standard will also apply to 20,000
water systems that serve at least 25 of the same people more than six months of
the year, such as schools, churches, nursing homes, and factories. EPA estimates
that five percent, or 1,100, of these water systems, serving approximately 2
million people, will need to take measures to meet the new arsenic standard. Of
all of the affected systems, 97 percent are small systems that serve fewer than
10,000 people each.
Arsenic occurs naturally in rocks and soil, water, air, and plants and animals. It can be further released into the environment through natural activities such as volcanic action, erosion of rocks, and forest fires, or through human actions.
Approximately 90 percent of industrial arsenic
in the U.S. is currently used as a wood preservative, but arsenic is also used
in paints, dyes, metals, drugs, soaps, and semi-conductors. Agricultural
applications, mining, and smelting also contribute to arsenic releases in the
Higher levels of arsenic tend to be found more
in ground water sources than in surface water sources (i.e., lakes and rivers)
of drinking water. Compared
The average increase in household cost for
water that meets the new arsenic standards depends on the size of the water
system and how many people are served by that system. For small community water
systems (those serving fewer than 10,000 people), the increase in cost is
expected to range between $38 and $327. For community water systems that serve
greater than 10,000 people, annual household costs for water are expected to
increase from $0.86 to $32.
Systems may apply for financial assistance
through EPA's drinking water state revolving fund. Since 1996, EPA's drinking
water state revolving fund program has made available $3.6 billion to assist
drinking water systems with projects to improve their infrastructure. EPA has
funded over 1000 loans for projects around the country. In addition to financial
assistance, compliance period extensions of up to 9 years (resulting in a total
compliance period of 14 years) are available to small systems through an
How soon after publishing the final rule
will the changes take effect?
All community water systems and all non-transient
non-community systems that exceed the MCL of 10 micrograms per liter will be
required to come into compliance five years after the publication of the final
rule. Beginning with reports that are due by July 1, 2002, all community water
systems will begin providing health information and arsenic concentrations in
their annual consumer confidence report (CCR) for water that exceeds one-half
the new MCL.