In 2004 and 2005, monitors reporting to the U.S. Environmental Protection Agency found potentially harmful levels of the weedkiller atrazine in the South Fabius River and Youngs Creek watersheds in northeastern Missouri. Some studies have shown that atrazine can produce hermaphroditic frogs and male frogs with ovaries and eggs, although the level of exposure has varied in those studies. One study of men who worked in a factory that produced atrazine found prostate cancer levels in those exposed to the chemical were 8.4 times higher than in the general population.

Atrazine, a white, odorless chemical used to control grasses and broad-leafed weeds, is the second most widely used herbicide in the U.S. and is especially popular among Midwest corn growers. It interrupts the photosynthesis process in plants.

“Atrazine works really well,” said Dr. John Kraemer, director of the Center for Environmental Analysis at Southeast Missouri State University.

The center has been testing wells in Dunklin and Stoddard counties for atrazine and other chemicals for the past three years. The EPA’s maximum atrazine concentration for water is 3 parts per billion. At some times of the year in those heavily farmed counties, the chemical has been found at levels of parts per million instead of parts per billion, Kraemer said. The difference is huge, basically a factor of 1,000.

Kraemer said 80 percent of the wells the center tests in those counties exceed the EPA limits for atrazine and other toxic chemicals.

The European Union, which employs a more precautionary model for regulating chemicals than the U.S., has banned atrazine. In the U.S., the EPA renewed its approval of the herbicide in 2006 while sanctioning further tests of watersheds, tests conducted by the chemical’s Swiss manufacturer, Syngenta. The EPA reviewed 19 laboratory and field studies and concluded that atrazine does not adversely affect gonadal development in amphibians and that additional testing on its effects is not necessary. The EPA is reviewing its conclusion that atrazine poses no cancer risk to humans. But drinking water containing atrazine for long periods may damage the heart and liver. The Center for Environmental Analysis often finds high levels of atrazine in combination with other chemicals, such as the insecticide malathion. When this occurs, findings at such high levels are a concern. “It is for me,” Kraemer said. “… The combination can be adverse.”

Kraemer said toxic chemicals usually are tested individually. That is all the law requires. Chemicals rarely are tested in combination with another. But he is finding other chemicals like the powerful pesticides phorate and azinophos methyl at levels as high as atrazine’s.

Kraemer thinks multiple effects need to be tested. Terry Timmons, the DNR’s groundwater monitoring section chief in Jefferson City, Mo., said that type of testing is expensive. “The chemical registrants are only worried about getting registered for their product,” he said.

But Kraemer’s findings of multiple chemicals in high concentrations in private Bootheel wells is a concern, Timmons said. “From an environmental standpoint you start to worry about the mixture he might be seeing.”

Drilling a deeper well could be the solution to the presence of chemicals but presents an aesthetic problem because deeper water contains a large amount of iron. “You would not get good quality water without an iron removal process,” Timmons said.

Forty-two percent of Missouri’s population depends on groundwater for drinking water. Municipal water systems monitor their own drinking water. The DNR tests public water supplies serving at least 25 people or 15 service connections. The state does not test private wells, although the Department of Health and Senior Services will conduct tests if there are reasons to suspect the quality of the drinking water.

Full Story: http://www.semissourian.com/apps/pbcs.dll/article?AID=/20080301/NEWS01/194896695