In a recent report, the National Resources Defense Council (NRDC) found that the commonly-used herbicide atrazine has pervasively contaminated watersheds and surface water in the Midwestern and Southern US, and that the Environmental Protection Agency (EPA) is not using the best available science to detect the problem.  Atrazine, used as a weed killer on corn, sorghum, sugarcane, and lawns, is regulated under the Safe Drinking Water Act (SDWA) and the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA).  Under SDWA, EPA has determined that no more than 3 parts per pillion (ppb), as a yearly average, of atrazine may be present in drinking water.

The NRDC Report, “Poisoning the Well: How the EPA is Ignoring Atrazine Contamination in Surface and Drinking Water in the Central United States,” analyzed EPA monitoring data for surface and drinking water and found that all 40 watersheds tested had detectable atrazine levels, with more than half of those watersheds having average concentrations above 1 ppb, the amount at which aquatic vegetation is affected.  The Report also found that both watersheds and drinking water systems had one-time peak atrazine concentrations well above 3 ppb; the highest peak concentration in a drinking water system was almost 40 ppb.  Residents of many of the communities with atrazine spikes were unaware of the problem – testing is typically conducted by the chemical’s manufacturer, who reports the data directly to the EPA.  Unless the concentration is above the 3 ppb yearly average, residents are generally not warned.

(more…)