The Environmental Protection Agency (EPA) has proposed a new drinking water standard that would lower the acceptable level of arsenic in drinking water from 50 parts per billion to five parts per billion.
Critics of the proposal contend such a reduction is not justified by the science and would impose severe costs on municipal water departments across the country.
A National Academy of Sciences panel determined last year that the current 50 parts per billion standard places Americans at an unacceptable risk of bladder cancer, lung cancer, and other skin, heart, and lung ailments. The illnesses were linked to arsenic in drinking water by studies of contamination in Taiwan, Argentina, and Chile. Long-term exposure has also been linked to skin and prostate cancer, anemia, nerve damage, and circulatory problems.
Arsenic occurs naturally in rocks and soil, and is used in industrial processes to make paints, dyes, drugs, soaps, and semiconductors. The proposed new standard would be especially burdensome on water systems in the West, which rely heavily on groundwater and wells for drinking water supplies.
The 50 parts per billion limit was set in 1942, before arsenic was known to be toxic, and water suppliers have not disputed the need to lower the standard. But the industry strongly opposes the five-parts-per-billion limit, arguing the science is too incomplete to justify setting the limit that low.
EPA contends that lowering the national standard to five parts per billion—the equivalent of five drops of water in an Olympic swimming pool—could prevent between 65 and 125 cancers in the general population each year. Critics say the agency overestimated cancer risk by ignoring a Utah study that showed insignificant increases in illness in a county where arsenic is present at levels most common throughout the U.S.
The uncertain benefits associated with dramatically lowering the arsenic standard would come at a substantial cost, industry sources say. According to the American Water Works Association, meeting the standard would require an estimated $14 billion in capital investments and $1.5 billion in annual operating costs.
State officials in Idaho estimate that one in five community water systems in the state would not meet the proposed standard. Falls Water Co., which provides water to suburban Idaho Falls, has four wells with arsenic levels between five and seven parts per billion, slightly higher than would be allowed by the new standard. Building a treatment plant to remove arsenic would cost between $4.4 million and $12.4 million, company officials say.
The company estimates its customers would see cost increases of between $279 and $643 a year—a high price to pay for a health standard based on questionable science, said Falls Water Co. Manager Scott Bruce.
“We’re not averse to doing what we need to do to provide the safest water possible, but we want the regulators in Washington to realize you’re going to have an impact on people financially that may not be able to handle that,” Bruce said.
EPA disagrees on the costs, estimating the new rule would cost the average homeowner served by a small water system an additional $85 a year.
After taking public comment on the new rule, EPA is expected to announce its decision early next year. Small water systems would have three years to comply with the regulations.
Tom Bell is editor of U.S. Water News, Halstead, Kansas.
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