Excessive Herbicide Levels Found in Midwest’s Water in Summer

During the peak growing season, concentrations of herbicides in middle America’s drinking water can soar to levels much higher than federal standards, says an environmental study released Thursday.

The chemical industry and local water system officials say this does not necessarily mean the water is unsafe to drink. But the Environmental Protection Agency said the findings are cause for concern.

The study by the Environmental Working Group, a nonprofit research organization, collected samples of tap water every few days in 29 communities from mid-May to July. The samples showed the presence of at least one weedkiller in all but one city: Memphis, Tenn., where drinking water comes from deep wells.

The research focused on two of the most common farm herbicides: atrazine and cyanazine. Some samples disclosed the presence, however, of up to nine weedkillers in a single glass of Midwestern water.

Concentrations of atrazine, which in high exposure levels has been linked to cancer in animals, were found to exceed federal standards at least once in 14 communities studied. Concentrations of cyanazine, another suspected carcinogen, were above the standards at least once in 18 communities.

In Danville, Ill., 94% of cyanazine samples and 88% of atrazine samples were above federal guidelines from May to July. In Kansas City, Kan., 56% of cyanazine samples and 44% of atrazine samples exceeded EPA health standards.

EPA enforcement standards permit water systems to exceed the maximum level for a herbicide--in atrazine’s case, 3 parts per billion--for less than a year.

There are no EPA enforceable standards for some herbicides, such as cyanazine. Instead, the agency has issued health advisories recommending maximum levels in drinking water and food. For cyanazine, the amount for water is 1 part per billion.

The Assn. of Metropolitan Water Agencies, which represents local water systems, said the study “incorrectly and misleadingly” failed to acknowledge that EPA standards are based on a running annual average, not single measurements.

But the environmental group said the study raises questions about those standards and the impact of repeated, periodic exposure, especially among children.