NRDC raises concerns about MCL for atrazine because of alleged undetected spikes in concentration in drinking water

NRDC raises concerns about MCL for atrazine because of alleged undetected spikes in concentration in drinking water

Under the Safe Drinking Water Act, municipal water supplies are typically tested for chemicals, including atrazine, four times a year; atrazine acts to prevent the emergence of weed seeds. The EPA considers an annual average atrazine level below 3 parts per billion as safe for human consumption. But biweekly data collected by the EPA from 139 municipal water systems found that atrazine was present 90 percent of the time and that 54 water systems had one-time spikes above 3 parts per billion in 2003 and 2004, according to an analysis by the NRDC. One could reasonably anticipate such spikes given that in agricultural areas atrazine is applied to the vast majority of corn, sorghum and sugar cane fields.
 
NRDC argues that the EPA's limits are too lenient, given studies showing the effects of low levels of atrazine on rats and other animals and the fact that it is nearly impossible to epidemiologically trace the chemical's effects on humans. NRDC argues that atrazine is an endocrine disrupter that acts in the body at extremely low levels; as such, the so-called spikes matter.
 
Atrazine’s manufacturer Syngenta called the NRDC study alarmist and said the spikes fall within one- and 10-day limits that the EPA considers safe. Syngenta stated that "Atrazine is one of the best studied, most thoroughly regulated molecules on the planet," and that "Those momentary spikes are not going to be injurious to human health."
 
A synoptic overview of the toxicology of atrazine in humans can be found at http://toxnet.nlm.nih.gov/cgi-bin/sis/search/f?./temp/~Evsxoq:1:human. A synoptic overview of the toxicology of atrazine in animals can be found at http://toxnet.nlm.nih.gov/cgi-bin/sis/search/f?./temp/~Evsxoq:1:animal. IRIS data on atrazine, including the RfD, can be found at http://toxnet.nlm.nih.gov/cgi-bin/sis/search/f?./temp/~70Snrm:1:FULL.
 
The NRDC report can be found at http://www.nrdc.org/health/atrazine/default.asp.