Environmental experts say the contamination of underground water supplies by runoff from farm chemicals
is now happening across broad areas of the nation's breadbasket and is more threatening to drinking water
supplies than other conventional environmental problems such as factory discharges or toxic waste dumps.
Every year since 1980 the Iowa Geological Survey has found trace amounts of agricultural chemicals in the
underground water supplies that serve hundreds of thousands of people. The survey found that 53% of the
shallow wells surveyed in Iowa contained pesticide residues. In Kansas, 28% of the farm wells sampled this
year contained high levels of nitrates, a byproduct of nitrogen fertilizers. 50 communities in Iowa have
nitrate levels in their drinking water that exceed the federal standards. Recent studies have shown that
people living in rural parts of Iowa, Nebraska and Illinois have higher than normal risks of developing
leukemia, lymphoma and other cancers. Some of the pesticides found in the water in the Middle West are
known to cause cancer or are suspected of it. A recent study said about 785,000 (27%) of residents of Iowa
drink water containing traces of one or more pesticides. The pesticides most commonly found in Iowa's
groundwater are the weed-killers alachlor, atrazine and cyanazine. Alachlor, banned in Canada, has been
shown to cause cancer in laboratory animals. Manufactured by the Monsanto Company, alachlor is
marketed under the brand name Lasso. In Aug. 1986, Iowa Governor Terry Branstad proposed spending $27
million over 3 years to reduce the amount of fertilizers and pesticides farmers put into the soil. Since 1960,
the use of nitrogen fertilizers have increased more than 5 times in Iowa. In the same time period, in some
areas the concentrations of nitrates in the groundwater have tripled. Without exposure to air and sunlight,
pesticides that would have normally broken down in two months may last 6 months to a year underground.
According to health officials, the shallow wells used by most Midwestern farm families are more prone to
contamination because the people drink the water straight whereas in industrial areas the water is treated.
According to the Iowa Department of Natural Resources, even the best treatment available is not
significantly reducing the concentration of pesticides in water and the only way to solve the problem is to
change human attitudes and behavior.
--Peter Montague, Ph.D.
Descriptor terms: water; drinking water; groundwater; ia; il; ks; ne; fertilizer; nitrate; pesticides, alachlor; atrazine;