In 1950, less than 10 percent of cornfields were chemically treated. Fifty-five years later, 98 percent were sprayed with pesticides. The most abundantly used is the weedkiller atrazine, which in 2005 was applied to 81 percent of Illinois cornfields—nearly 10 million acres of soil. With so much acreage now planted in field corn, fungus, which breeds on corn stubble, has emerged as a significant pest. The use of fungicides is now sharply up, refamiliarizing rural folk with an icon of the past: the low-flying crop duster droning above the fields in midsummer.

Pesticides do not always stay on the fields where they are sprayed. They evaporate and drift in air. They dissolve in water and flow downhill into streams and creeks. They bind to soil particles and rise into the air as dust. They migrate into glacial aquifers and thereby enter groundwater. They fall in the rain. They are found in snowflakes. And fog. And wind. And clouds. And backyard swimming pools. Little is known about how much goes where. By 1993, 91 percent of Illinois’s rivers and streams showed pesticide contamination. Ten years later, the streams and rivers within my childhood watershed contained 31 different pesticides, and atrazine was in all samples. These chemicals travel in pulses: pesticide levels in surface water during the months of spring planting—April through June—are sevenfold those during winter and often contain levels of atrazine that exceed legal limits for drinking water. Even less is known about pesticides in ground-water. About 18 percent of all samples of groundwater surveyed in Illinois in 2006 contained atrazine byproducts, while a 1992 study found that one-quarter of private wells tested in central Illinois contained agricultural chemicals of some type. Drinking water wells in the Havana Lowlands region of Mason County showed some of the most severe contamination. A 2009 report identified two public drinking water systems in Illinois with running annual averages for atrazine in tap water that exceeded legal limits. In the same year, the wind blowing across my home county was so full of weedkiller that the air itself withered grape vines in a local vineyard.

Sandra Steingraber. Living Downstream: An Ecologist’s Personal Investigation of Cancer and the Environment. Da Capo Press. Kindle Edition. Pg. 4-5.