Atrazine

Summary

Atrazine is the second most widely used herbicide in U.S. agriculture, with the Environmental Protection Agency estimating that about 70 million pounds are applied to crops every year. 

Atrazine-laced runoff from farm fields pollutes streams, rivers and groundwater, which many communities depend on for drinking water. It resists degradation from heat and sunlight, so it remains in the environment for a long time. Atrazina has long been banned in Europe due to concerns about groundwater contamination and harm to wildlife.

EWG research shows that atrazine is the most commonly detected pesticide in tap water.  It can be found at  concentrations higher than the Environmental Protection Agency’s legal limit of 3 parts per billion, or ppb, of atrazine in treated tap water.

Water utilities struggle to remove the chemical, particularly in the spring, when millions of pounds  are applied to corn and other crops.

In 2012, Syngenta, the herbicide’s sole manufacturer, settled for $105 million a lawsuit filed by more than 1,000 Midwestern water providers over the cost of removing atrazine from drinking water. Some utilities said this amount doesn’t begin to cover the cost of removal.

California’s legal maximum for atrazine in tap water is 1 ppb, stricter than the federal standard. In 1999, the state’s Office of Environmental Health Hazard Assessment set a public health goal of just 0.15 ppb for atrazine in drinking water, based on a study finding increased rates of mammary tumors in rats exposed to the chemical. Public health goals are not legally enforceable.

As scientists continue to study endocrine disruptors – chemicals that interfere with the body’s hormones – more information becomes available that shows that these contaminants are harmful even at very low levels. EWG’s health guideline of 0.1 ppb for atrazine is based on epidemiological studies of exposure to atrazine in drinking water. This health guideline protects against hormone disruption and harm to the developing fetus and the reproductive system.

Click here to see the nationwide testing results for atrazine.

How does atrazine get into tap water?

Atrazine is used to control broadleaf and grassy weeds. It is sprayed on row crops, especially corn, and in some areas is used on residential lawns. It can enter waterways in agricultural runoff. 

What are the toxic effects of atrazine in drinking water?

Atrazine is a hormone disruptor that even at low doses affects the human reproductive system, posing the greatest risk during pregnancy and early childhood. Research suggests it acts by depressing a hormone known as LH, which leads to increased production of estrogen and prolactin in females and to changes in testosterone levels in males.

A University of California, Berkeley study has reported that low-level exposures can disrupt frogs’ hormone systems.

In 2011, the EPA Scientific Advisory Panel reviewed the human health effects of atrazine and concluded that there is suggestive evidence showing that atrazine can increase the risk of ovarian cancer, non-Hodgkin lymphoma, hairy-cell leukemia and thyroid cancer.

Other studies suggest human health may be affected by low levels of atrazine in drinking water:

• In 2017, a University of Illinois study reviewed data for more than 130,000 births, reporting a statistically significant association between preterm births and atrazine in drinking water. The average concentration of atrazine was one-seventh of the EPA’s limit.
• A 2013 University of Nebraska–Lincoln study detected an elevated risk of non-Hodgkin lymphoma for people who had both atrazine and nitrate in their drinking water.
• A 2011 study from a Vermont state agency compared the menstrual cycles of women drinking atrazine-contaminated water in Illinois to those of women in rural Vermont, where atrazine is used sparingly. The Illinois women reported more menstrual cycle irregularity and a higher likelihood of reduced levels of reproductive hormones.
• A 2011 study from the French National Institute of Health and Medical Research reported an increase in fetal growth restriction and small head circumference in French babies whose mothers drank atrazine-contaminated tap water during the first trimester of pregnancy. Atrazine levels were below the EPA’s limit.

What can be done to reduce exposure to atrazine in drinking water?

The only long-term solution to keep atrazine and other pesticides out of drinking water is to minimize pesticide use and to eliminate farm runoff that contains pesticides. 

Keeping contaminants out of water in the first place is more cost effective than removing them year after year. Measures such as establishing and maintaining buffer zones of grasses along rivers and streams can do a lot to cut farm pollution entering sources of drinking water.

Some states, including Kansas and Nebraska, have published guidance for farmers to reduce atrazine pollution of water. EWG believes that Congress should fully fund incentives to adopt conservation practices that reduce pesticide runoff and make drinking water protection a priority.

To protect yourself, get more information about whether your drinking water contains atrazine. You can:

• Use EWG’s Tap Water Database to see whether your water system has tested and detected atrazine. If your utility doesn’t appear in our database, or if you want to learn more about its tests, contact the utility directly, a nearby water utility or your local public health department.
• Consider getting your water tested independently if you live near cornfields or other agricultural lands; make sure to consult with local water experts about the best time to collect a water sample.
• Install a filter certified to remove atrazine if it has been detected in your water.

References

Associated Press, Syngenta Pays Millions in Settlement to Farming States. The Topeka Capital-Journal, 2013. Available at cjonline.com/news/2013-01-25/syngenta-pays-millions-settlement-farming-states

California Office of Environmental Health Hazard Assessment, Public Health Goal for Atrazine in Drinking Water. 1999. Available at https://oehha.ca.gov/media/downloads/water/public-health-goal/atrazf.pdf 

C. Chevrier et al., Urinary Biomarkers of Prenatal Atrazine Exposure and Adverse Birth Outcomes in the PELAGIE Birth Cohort. Environmental Health Perspectives, 2011, 119(7):1034–1041.

L.A. Cragin et al., Menstrual Cycle Characteristics and Reproductive Hormone Levels in Women Exposed to Atrazine in Drinking Water. Environmental Research, 2011, 111(8):1293–1301.

E. Mendez, Presentation to the Scientific Advisory Panel. Atrazine Re-Evaluation: Scientific Considerations in Potential Sensitivity of Infants & Children. Environmental Protection Agency, Office of Pesticide Programs, Health Effects Division, July 26–29, 2011.

Environmental Protection Agency Science Advisory Panel, Meeting Minutes of the FIFRA Scientific Advisory Panel meeting held July 26–28, 2011 on the Re-Evaluation of the Human Health Effects of Atrazine: Review of Non-Cancer Effects, Drinking Water Monitoring Frequency and Cancer Epidemiology. Oct. 26, 2011.

EPA, Office of Pesticides, Environmental Fate and Effects Division. Refined Ecological Risk Assessment for Atrazine. April 2016. Available at www.regulations.gov/document?D=EPA-HQ-OPP-2013-0266-0315.

European Commission, Review Report for the Active Substance Atrazine. Finalized in the Standing Committee on the Food Chain and Animal Health at its meeting on Oct. 3, 2003 in support of a decision concerning the non-inclusion of atrazine in Annex I of Directive 91/414/EEC and the withdrawal of authorisation for plant protection products containing this active substance. European Commission Health and Consumer Protection Directorate-General, 2003, SANCO/10496/2003-final.

T. Hayes et al., Demasculinization and Feminization of Male Gonads by Atrazine: Consistent Effects Across Vertebrate Classes. Journal of Steroid Biochemistry and Molecular Biology, 2011, 127:64-73.

M.G. Rhoades et al., Atrazine and Nitrate in Public Drinking Water Supplies and Non-Hodgkin Lymphoma in Nebraska, USA. Environmental Health Insights, 2014, 7:15-27.

L.T. Stayner et al., Atrazine and Nitrate in Drinking Water and the Risk of Preterm Delivery and Low Birth Weight in Four Midwestern States. Environmental Research, 2017, 152:294-303.