Pesticide, Herbicide Concentrations Decline in Corn Belt Waterways

Published January 21, 2010

Pesticide and herbicide concentrations in the waterways of major corn-producing states are in a long-term decline, according to the U.S. Geological Survey.

The USGS National Water-Quality Assessment Program has since 1996 been tracking 11 common pesticides and herbicides in 31 waterways in Illinois, Indiana, Iowa, Nebraska, and Ohio. According to its new report, Trends in Pesticide Concentrations in Corn-Belt Streams, nine of the 11 pesticides and herbicides are declining, one is remaining steady, and one is increasing.

“Overall, combined study results indicate that trends in pesticide concentrations in Corn Belt streams and rivers during 1996-2006 were largely explained by corresponding trends in annual use and that major reductions in the use of some pesticides resulting from regulatory actions or market forces generally resulted in corresponding declines in stream and river concentrations,” the report explained.

USGS studied concentrations of many other pesticides and herbicides that were less prevalent than the 11 included in the study. All of these chemicals were below analytical detection limits in most samples, and thus no trends could be reported.

Benefits of Reduced-Till Farming

“Much of this improvement is a result of the increase in the practice of reduced tillage farming which allows previous crop residue remaining on the land to capture both water and pesticides that previously ran off the acreage into nearby water courses,” said Jay Lehr, Ph.D., science director for The Heartland Institute and an expert on groundwater issues.

“Nearly 40 percent of American farmland now utilizes either reduced or no-till practices that benefit the environment and agricultural economics. Reduced and no-till practices reduce labor, equipment maintenance, and fuel use while improving soil quality,” Lehr explained.

James M. Taylor ([email protected]) is a senior fellow of The Heartland Institute and managing editor of Environment & Climate News.

For more information …

USGS National Water-Quality Assessment Program, Trends in Pesticide Concentrations in Corn-Belt Streams: