Each spring, the chemical herbicide atrazine is spread on corn and sorghum fields throughout eastern Kansas.

When the rains come, atrazine residue is washed away, traveling into surface water and eventually winding its way into many public water supply systems.

The chemical’s presence in drinking water has come under scrutiny from the Natural Resources Defense Council. Kansas is among the Midwestern states most at risk for contamination, the NRDC reports.

The NRDC claims the Environmental Protection Agency isn’t collecting data that take into account spikes in atrazine levels occurring during spring runoffs.

“It’s kind of worse than ignoring the spikes. They are averaging them away,” said Andrew Wetzler with the NRDC.

A report recently released from the NRDC raises concerns that peaks in atrazine levels are a health risk to some groups and they aren’t being reported to those drinking the water.

The chemical’s largest manufacturer, Syngenta, and the agriculture industry say that atrazine levels aren’t violating EPA standards. And the EPA, an agency that typically errs on the side of caution, has spent years researching the chemical’s harmful effects.

After 50 years of use and 6,000 studies, atrazine has proven to be safe, Syngenta spokesman Steven Goldsmith said.

“We know that levels of atrazine are significantly below the average set by the EPA. And on top of that, (the EPA) provides for a significant safety factor,” he said.

Important to farmers

With 60 million to 80 million pounds of atrazine applied each year, the chemical is the most widely used herbicide in the United States. Atrazine, which is applied at the start of the growing season, is used for killing broadleaf weeds.

“The only reason atrazine is so important to farmers today is that no other product has come along that replaces it,” said Jere White, executive director of the Kansas Corn Growers Association and the Kansas Grain Sorghum Producers Association.

Not using the herbicide would cost corn and sorghum farmers about $20 to $30 an acre, which would translate into a $120 million loss each year for Kansas farmers.

“There are many years where $30 an acre might be the difference between a profit and a loss. And just to lay that on the table when the science is not there to justify it should be a concern to every farmer,” White said.

Because of its wide use and classification as an endocrine disrupter, atrazine has been at the top of the list of NRDC’s concerns for a number of years, Wetzler said. Endocrine disrupters can mimic and affect the normal hormonal function of organisms, which can alter the reproductive systems.

Studies have shown that concentrations of atrazine as low as 0.1 part per billion have altered the development of sex characteristics in male frogs, causing female sex characteristics, hermaphrodites or the presence of eggs, the NRDC reported. These findings indicate that during periods of development for brain and reproductive organs, the timing of exposure to atrazine might be more critical than the amount.

“Relying on an annual running average, the EPA is essentially allowing very large spikes … of a chemical that can be very disruptive to pregnant women and young people during the stages of development,” Wetzler said. “Is it a huge cause for concern for a 70-year-old, 180-pound white man? Probably not. Would I want my pregnant wife drinking it? No.”