Atrazine: Frogs, Farms and Pharmaceuticals

The world’s most heavily used pesticide is turning frogs into hermaphrodites. In this program, biologist Dr. Tyrone Hayes presents his research and discusses the complicated process through which the EPA decides whether to ban a potentially dangerous compound.

Research finds that low-level exposure to a common weedkiller transforms male frogs into hermaphrodites.

Dr. Hayes, who is a professor of Integrative Biology at the University of California at Berkeley, has published studies in the journals Nature, Proceedings of the National Academy of Sciences, and Environmental Health Perspectives linking very low concentrations of atrazine in water to hermaphroditism and other serious deformities in frogs, both in controlled lab studies and in field studies across the United States.

What is especially striking about Dr. Hayes’ research with atrazine is the low levels at which the effects were observed. Data from a 2003 study in Environmental Health Perspectives show that after exposure to 0.1 parts per billion (ppb) of atrazine, over half of male frogs developed major reproductive abnormalities: approximately 20% became hermaphrodites, while an additional 36% had under-developed testes. 0.1 parts per billion is one thirtieth of EPA's allowable limit of 3 ppb in drinking water.  Low levels of atrazine are commonly found in streams, groundwater, drinking water, and even rainwater in regions of the country where atrazine is used, including North Carolina.   A ten-year study of water quality in eastern North Carolina recently conducted by the US Geological Survey found atrazine residues in over 80% of the streams sampled.

An estimated 603,000 pounds of atrazine are used in North Carolina each year on corn alone – it is also sometimes used on lawns by homeowners and lawn care companies. In agricultural regions of the country, atrazine is found in the vast majority of streams, both rural and urban. Atrazine has also been measured in drinking water supplies for the cities of Burlington, High Point, Greensboro, and Raleigh, NC. Typical drinking water treatment processes do not remove chemicals like atrazine.