Weed Killers By The Glass
September 1, 1995

Weed Killers By The Glass: Columbus, Ohio

Citizen Monitoring Results

Columbus drinking water is contaminated with cancer causing weed killers at levels that frequently exceed federal standards. Tests of city tap water found seven different pesticides or metabolites, with up to six in a single sample. The most common pesticide contaminant is atrazine, which was found in every tap water sample tested between May 15 and July 1, 1995. Cyanazine was also found in 100 percent of these same samples. During this test period approximately 3,500 infants in Columbus consumed infant formula reconstituted with water contaminated with seven toxic weed killers. (Note 1: Ershow, Abby G., and Cantor, Kenneth P. 1989. Total Water and Tapwater Intake in the United States: Population-Based Estimates of Quantities and Sources. Life Sciences Research Office; Federation of American Societies for Experimental Biology. Bethesda, MD)

Most of these weed killers are used in corn production. Since 1985, taxpayers have subsidized Ohio corn growers at a rate of $164 million per year, for a ten year total of $1.64 billion. Farmers in turn pay nothing to clean up the water. The pesticide industry claims that farmers' weed control cost would double if these polluting herbicides were banned. Assuming the industry claim is true, the added costs to farmers would amount to just 11 percent of the value of the subsidy taxpayers pay to these corn farmers each year.



Causes mammary gland cancer in female rats in repeated studies.(Note 2: Copley, Marion. 1989. Follow-up to the Third Peer Review of Atrazine. EPA. Washington, D.C.; International Agency for Research on Cancer. 1991. World Health Organization. IARC Monographs on the Evolution of Cancer Risk to Humans. Vol. 53.) Classified by the EPA as a possible human carcinogen. Federal health standard in drinking water -- 3 parts per billion (ppb), European Drinking Water Standard -- 0.1 ppb.


  • Found in 100 percent of 14 tap water samples
  • 43 percent of samples were above the federal health standard
  • Highest level found -- 8.74 ppb, nearly three times the federal health standard.
  • Average concentration -- 3.54 ppb, also above the federal health standard.



Causes mammary gland cancer in rats and birth defects in rats and rabbits in repeated studies. Causes genetic mutations. According to the EPA this makes cyanazine a potent carcinogen.(Note 3: Dykstra, William. 1991. Peer Review of Cyanazine (Bladex). EPA. Washington, D.C.) Classified by the EPA as a possible human carcinogen, required birth defects warning on the product label. Federal health guideline in drinking water -- 1 ppb. European Drinking Water Standard -- 0.1 ppb.


  • Found in 100 percent of samples
  • 79 percent of samples were above the federal health advisory.
  • Highest level found -- 4.40 ppb, more than four times the federal health advisory.
  • Average concentration -- 2.09 ppb, more than twice the federal health advisory.


Tests for Multiple Weed Killers


  • Seven pesticides or metabolites -- atrazine, cyanazine, metolachlor, alachlor, acetochlor, desisopropylatrazine, and desethylatrazine -- were found in a single sample of Columbus tap water collected on June 2, 1995.
  • These seven pesticides or metabolites include two pesticides classified by EPA as probable human carcinogens, three pesticides classified as possible human carcinogens, one pesticide that causes birth defects in animal studies, and three pesticides that disrupt the normal functioning of the hormone system.
  • Federal drinking water standards do not account for this simultaneous exposure to multiple pesticides (or other contaminants) in drinking water, and allow cancer risks from these weed killers up to 29 times higher than the federal government allows from the same chemicals in food.


Ohio Corn Farmers Used 9.55 Million Pounds Of Herbicides In 1994


Herbicide Acres Treated, 1994 Use, 1994 (lbs.)
Acetochlor 148,000 300,000
Alachlor 814,000 1,618,000
Atrazine 2,849,000 3,568,000
Cyanazine 814,000 1,704,000
Metolachlor 1,100,000 2,086,000
Simazine 259,000 275,000

(Note 4: USDA 1995. Agricultural Chemical Usage: 1994 Field Crops Summary.)