The Natural Resources Defense Council has issued a report that drinking water containing the herbicide atrazine could pose a greater public health risk than previously thought because regular municipal monitoring doesn't detect frequent spikes in the chemical's levels. Scientists with Syngenta, the main manufacturer of atrazine, called the NRDC report alarmist and said the spikes fall within limits that the Environmental Protection Agency considers safe.
University of Missouri Extension Water Quality Specialist Bob Broz says because atrazine has been one of the longest used and effective herbicides, it has been under close scrutiny by the EPA for years.
"After years and years of tests and looking at it and saying, 'Why is this product being used? What can we do with it? Are there other alternatives out here that are economically viable and still as effective a job?'," Broz said. "Most of the research that has come back based on what we normally look at has shown that atrazine is a very safe product."
Broz says EPA, regardless of what they see as the level that they think is dangerous, goes beyond that on the off chance that someone could have an adverse reaction and builds in a safety factor. In the case of atrazine, EPA adopted a federal lifetime drinking water standard at three parts-per-billion, a level containing a 1,000-fold safety factor.
"In most cases atrazine if used under label conditions works very effectively," Broz said. "Now what we have learned is that different soil conditions or different rain conditions can play a role in how much atrazine we're actually going to see runoff the field. The farmers don't want this coming off the field either. It it's not on the field and where we put it, it's not going to be good for weed control and in that case it's costing the farmer a lot more money."
Broz says most farmers are trying to figure out ways to keep atrazine where they put it and to make sure that the levels they use are under the label recommendations, which is the law.
"In many of the watersheds where we are actually monitoring for atrazine and atrazine use we have not seen any problem whatsoever," Broz said. "Syngenta is working very, very closely with EPA in doing monitoring in a series of watersheds where they are taking water samples every four days throughout the growing season."
Broz says this will allow them to see what level of atrazine is in the water through that whole entire period, so that what kind of runoff and its impact to people and the environment can be determined.
In 2008, none of the 122 community water systems monitored in 10 states where atrazine is used most exceeded the federal standards set for atrazine in drinking water or raw water.
"These low levels pose no threat to human health," said Tim Pastoor, principal scientist for Syngenta. "A person could drink thousands of gallons of water containing three parts per billion atrazine every day for a lifetime, and still not be affected."
Despite all of this, 43 water systems in six states recently filed a lawsuit suing atrazine's manufacturers to force them to pay for removing the chemical from drinking water.
"A lot of this I believe has to do with lawyers who are looking for a mark if life, for something they can hang their hat on and say this is an issue we need to face or look at it more closely," Broz said. "I agree, we do need to look at this more closely, but if the data we have collected over this long period of time does not demonstrate that there is a real issue I can't see where there's really a leg to stand on as far as a lawsuit would go."
Broz says that the new re-registration of different herbicides and pesticides is going to become much stricter. Even now EPA is trying to determine should be looked at. For example, is a carcinogenic situation the main issue or is there something else that needs to be looked at.