Atrazine: Poisoning the Well

Banned in the European Union and clearly linked to harm to wildlife and potentially to humans, the pesticide atrazine provides little benefit to offset its risks. In a new report, NRDC brings together for the first time the results of surface water and drinking water monitoring required by the U.S. EPA to create a more comprehensive analysis of atrazine pollution across the Midwestern and Southern United States. Approximately 75 percent of stream water and about 40 percent of all groundwater samples from agricultural areas tested in an extensive U.S. Geological Survey study contained atrazine. NRDC found that the U.S. EPA's inadequate monitoring systems and weak regulations have compounded the problem, allowing levels of atrazine in watersheds and drinking water to peak at extremely high concentrations.

In watersheds the presence of high one-time peak concentrations of atrazine is just as important as the concentration averaged over a few months or a year. Under the Safe Drinking Water Act (SDWA), the EPA has determined that no more than 3 parts per billion (ppb) of atrazine (as a running annual average) may be present in drinking water. Because it is an average, high maximum concentrations of atrazine contamination during spring runoff may not result in a violation of the standard if the remainder of the year has low or no atrazine contamination.

The toxicity associated with atrazine has been documented extensively. The adverse reproductive effects of atrazine have been seen in amphibians, mammals, and humans-even at low levels of exposure. Concentrations as low as 0.1 ppb have been shown to alter the development of sex characteristics in male frogs. When exposure coincides with the development of the brain and reproductive organs, that timing may be even more critical than the dose. Also of great concern is the potential for atrazine to act synergistically with other pesticides to increase their toxic effects.

Given the pesticide's limited usefulness and the ease with which safer agricultural methods can be substituted to achieve similar results, NRDC recommends phasing out the use of atrazine, more effective atrazine monitoring, the adoption of farming techniques that can help minimize the use of atrazine and prevent it from running into waterways.

NRDC recommends that consumers concerned about atrazine contamination in their water use a simple and economical household water filter, such as one that fits on the tap. Consumers should make sure that the filter they choose is certified by NSF International to meet American National Standards Institute (ANSI) Standard 53 for VOC (volatile organic compounds) reduction and therefore capable of significantly reducing many health-related contaminants, including atrazine and other pesticides. Learn more about choosing the right water filter. Help NRDC learn more about water treatment in your area by calling your utility, asking these questions about water treatment in your area and submitting this online form.