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Chemistry of the Corn Belt is changing

Some pesticides less concentrated in Corn Belt rivers.
Written by Harry Fuller, Contributor

The U.S. Geological Survey (USGS) says there are less toxic pesticides in America's Corn Belt rivers. The study released today covers the decade ending 2006.

The USGS says, "Declines in concentrations of the agricultural herbicides cyanazine, alachlor and metolachlor show the effectiveness of U.S. Environmental Protection Agency (EPA) regulatory actions as well as the influence of new pesticide products. In addition, declines from 2000 to 2006 in concentrations of the insecticide diazinon correspond to the EPA’s national phase-out of nonagricultural uses."

"Scientists studied 11 herbicides and insecticides frequently detected in the Corn Belt region, which generally includes Illinois, Indiana, Iowa, Nebraska and Ohio, as well as parts of adjoining states. This area has among the highest pesticide use in the nation — mostly herbicides used for weed control in corn and soybeans. As a result, these pesticides are widespread in the region’s streams and rivers, largely resulting from runoff from cropland and urban areas.

"Elevated concentrations can affect aquatic organisms in streams as well as the quality of drinking water in some high-use areas where surface water is used for municipal supply. Four of the 11 pesticides evaluated for trends were among those most often found in previous USGS studies to occur at levels of potential concern for healthy aquatic life. Atrazine, the most frequently detected, is also regulated in drinking water."

"Only one pesticide — simazine, which is used for both agricultural and urban weed control — increased from 1996 to 2006. Concentrations of simazine in some streams increased more sharply than its trend in agricultural use, suggesting that non-agricultural uses of this herbicide, such as for controlling weeds in residential areas and along roadsides, increased during the study period."

"Glyphosate, an herbicide which has had rapidly increasing use on new genetically modified varieties of soybeans and corn, and which now is the most heavily used herbicide in the nation, was not measured until late in the study and thus had insufficient data for analysis of trends."

Monsanto markets glyphosate as Roundup. Roundup does not meet with universal acceptance with some researchers questioning its safety.

The use of herbicides and pesticides is intensive in both the food industry and the biofuel industry that uses corn to make ethanol.

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