What is atrazine?

Atrazine is an herbicide used to control broadleaf and grassy weeds.  Atrazine is mainly applied to corn and soybean crops, but is also used on sorghum, sugarcane, pineapple, and Christmas tree farms.  This pesticide is a white crystalline solid organic compound that is available in many forms as a dry flowable, flowable liquid, water dispersible granular liquid, and a wetable powder.  Trade names for atrazine include aatrex and atratol, and atrazine is in the family of triazines.4,5

What is the distribution of atrazine?

Atrazine is one of the most heavily used herbicide in the United States.4  In 1990, over 64 million acres of cropland were treated with atrazine. This herbicide is used mainly in Indiana, Illinois, Indiana, Iowa, Kansas, Missouri, Nebraska, Ohio, Texas and Wisconsin.  In 1997 in Portage County, WI, atrazine was applied to 21,318 acres at 0.75 lbs/A/yr (total-15,988 lbs) for field corn, and 5,200 acres at 0.78 lbs/A/yr (total-4,056 lbs) for sweet corn.3

Atrazine is carried by water into the soil and other water bodies.  Microbial activity and other chemicals breakdown atrazine in soil and water, especially in alkaline conditions.  Occasionally, atrazine may bind to soil particles, but it generally leaches to groundwater.  Sunlight and evaporation do not reduce or affect atrazine.4,5


What is the drinking water regulation?

The Safe Drinking Water Act of 1974 requires that the EPA (Environmental Protection Agency) set safe drinking water standards for chemicals in drinking water.  Atrazine has entered surface water and groundwater mainly through runoff from herbicides used in row crops and wastewater from manufacturing facilities.  This potential for water contamination prompted the regulation of atrazine in 1992 with both the Maximum Contaminant Level Goal (MCLG) and Maximum Contaminant Level (MCL) being set at 3 parts per billion (ppb).  Between 1993 and 1995, public water supplies were required to collect water samples every three months for one year and test for atrazine.  If atrazine was above 1ppb, then testing had to be continued every three months.  If atrazine was above 3ppb, then the water was treated with granular activated charcoal.  Since its regulation, only licensed applicators may purchase and apply atrazine.4


Atrazine Levels in Portage County Well Water Samples

Where is the water contaminate?

Despite restrictions, atrazine has contaminated groundwater.   In fact, it was the second most frequently detected pesticide in the EPA’s National Pesticide in Drinking Water Wells Survey.4  Atrazine exceeds the MCL of 3ppb in the following states: Delaware, Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, New York, and Wisconsin.4  

In Portage County, 40% of the private wells tested have a detection of atrazine (small red dots on map)Of this 40%, 3% exceed the Drinking Water MCL of 3 ppb for atrazine (large red dots on map).1,2  The pink shaded areas on the map indicate moratorium areas where the use of atrazine is banned.

What are the health impacts?

Studies have shown atrazine to be slightly to moderately toxic to humans and animals, especially aquatic life.  Atrazine can be absorbed orally, through the skin, and inhaled.  The symptoms mimic many other illnesses.  They include abdominal pain; diarrhea; vomiting; and irritation to the eye, skin, and mucus membranes.  Short-term exposure can result in congestion of heart, lungs, kidneys; low blood pressure; muscle spasms; weight loss; and damage to adrenal glands.   A short-term exposure is defined as exposure above the MCL for short periods of time.  Long term exposure can result in weight loss; cardiovascular damage; retinal and some muscle degeneration; and cancer.  A long-term exposure is defined as a lifetime exposure above the MCL.4,5


How do we treat the water?


References and More Information

1.       Kraft, George & Mechenich, Dave.  (2000, January 1).  Portage County Groundwater Conditions.  Stevens Point, WI: Groundwater Management Subcommittee and Public Involvement/Education Subcommittee of the Portage County Groundwater Citizens Advisory Committee for Portage County Planning and Zoning Department.












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