Weed Killers By The Glass
September 1, 1995

Weed Killers By The Glass: Minneapolis, Minnesota

Citizen Monitoring Results

Minneapolis drinking water is contaminated with cancer causing weed killers at trace levels. Tests of city tap water found at least two different pesticides in a single sample. The most common pesticide contaminant is atrazine, which was found in 58 percent of tap water sample collected between May 25 and July 1, 1995. Cyanazine was also found in 17 percent of these same samples. During this test period approximately 3,150 infants in Minneapolis consumed infant formula reconstituted with water contaminated with trace levels of 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 Minnesota corn growers at a rate of $278 million per year, for a ten year total of $2.78 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 58 percent of 11 tap water samples
  • Highest level found -- 0.24 ppb.
  • Average concentration -- 0.11 ppb.



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 17 percent of tap water samples
  • Highest level found -- 0.31 ppb.
  • Average concentration --0.05 ppb.


The Presence of Multiple Weed Killers


  • Atrazine and cyanazine were both found in Minneapolis tap water.
  • 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.


In 1994, Minnesota Corn Producers Used 9.7 Million Pounds of Herbicides


Herbicide Acres Treated, 1994 Use, 1994 (lbs.)
Acetochlor 910,000 1,841,000
Alachlor 770,000 1,394,000
Atrazine 2,520,000 1,787,000
Cyanazine 910,000 1,439,000
Metolachlor 1,470,000 3,277,000
Simazine 0 0

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