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Debating How Much Weed Killer Is Safe in Your Water Glass

The New York Times, By CHARLES DUHIGG, August 23, 2009
http://www.nytimes.com/2009/08/23/us...agewanted=1&hp

For decades, farmers, lawn care workers and professional green thumbs have relied on the popular weed killer atrazine to protect their crops, golf courses and manicured lawns.

But atrazine often washes into water supplies and has become among the most common contaminants in American reservoirs and other sources of drinking water.

Now, new research suggests that atrazine may be dangerous at lower concentrations than previously thought. Recent studies suggest that, even at concentrations meeting current federal standards, the chemical may be associated with birth defects, low birth weights and menstrual problems.

Laboratory experiments suggest that when animals are exposed to brief doses of atrazine before birth, they may become more vulnerable to cancer later.

An investigation by The New York Times has found that in some towns, atrazine concentrations in drinking water have spiked, sometimes for longer than a month. But the reports produced by local water systems for residents often fail to reflect those higher concentrations.

Officials at the Environmental Protection Agency say Americans are not exposed to unsafe levels of atrazine. They say that current regulations are adequate to protect human health, and that the doses of atrazine coming through people’s taps are safe — even when concentrations jump.

But some scientists and health advocates disagree. They argue that the recent studies offer enough concerns that the government should begin re-examining its regulations. They also say that local water systems — which have primary responsibility for the safety of drinking water — should be forced to monitor atrazine more frequently, in order to detect short-term increases and warn people when they occur.

The E.P.A. has not cautioned pregnant women about the potential risks of atrazine so that they can consider using inexpensive home filtration systems. And though the agency is aware of new research suggesting risks, it will not formally review those studies until next year at the earliest. Federal scientists who have worked on atrazine say the agency has largely shifted its focus to other compounds.

Interviews with local water officials indicate that many of them are unaware that atrazine concentrations have sometimes jumped sharply in their communities. But other officials are concerned. Forty-three water systems in six states — Illinois, Indiana, Iowa, Kansas, Mississippi and Ohio — recently sued atrazine’s manufacturers to force them to pay for removing the chemical from drinking water.

Representatives of the E.P.A. and Syngenta, the company that manufactures most of the atrazine sold, say that current federal standards are based on hundreds of studies showing Americans are safe. In a written statement, the E.P.A. said that it applied large safety buffers in regulating atrazine and continued to monitor emerging science.

“The exposure that the agency allows under its atrazine drinking water regulations is at least 300 to 1,000 times lower than the level where the agency saw health effects in the most sensitive animal species tested,” the statement said. New studies, while raising important issues, do not “suggest a revision to E.P.A.’s current regulatory approach, which has been built on the review and consideration of hundreds of studies, including animal toxicity and human epidemiological studies dealing with atrazine,” the agency said.

Syngenta said the lawsuits were baseless.

But the head of another government agency voiced apprehension. “I’m very concerned about the general population’s exposure to atrazine,” said Linda S. Birnbaum, director of the National Institute of Environmental Health Sciences, a division of the Department of Health and Human Services. “We don’t really know what these chemicals do to fetuses or prepubescent children.”

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Also,

Toxic Waters Disputed Science

Articles in this series will examine the worsening pollution in American waters and regulators’ response.
Document Viewer:
Documents"N.R.D.C. Report: Poisoning the Well
Documents Holiday Shores v. Syngenta

Graphic of Atrazine Levels Across the Nation
Down left column: http://www.nytimes.com/2009/08/23/us...agewanted=1&hp