Atrazine is an herbicide commonly used to protect crops like corn and sugarcane from broadleaf weeds. It is also an endocrine disruptor, found to cause a variety of health problems if ingested, including weight loss, heart damage, and muscle spasms.
Despite these health effects, the U.S. EPA has a history of dismissing atrazine as a cause for concern in water. The agency’s conclusions in 2006, 2007, and 2009 were that either the pesticide did not pose a legitimate threat to human health or that protections were robust enough to dismiss that threat. It currently regulates atrazine at a Concentration Equivalent Level of Concern of 10 ppb, though a draft risk assessment this year concluded that the herbicide may pose a high risk to plants and animals on land and in the water.
The concerns around atrazine in drinking water appear to be most serious in Wisconsin, a state in the top 10 nationally for its number of farms and one where a severe case of probable atrazine poisoning was recently highlighted by the Wisconsin Center for Investigative Journalism (WCIJ).
“Wisconsin controls the use of atrazine more than any other state,” said Bill Cosh, the communications director for the Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP).
DATCP is tasked with flagging areas with wells contaminated by atrazine above the state’s enforcement standard of 3 ppb, deeming them “prohibition areas.” It has flagged 101 such areas and Cosh estimates that these areas total about 1.2 million cropland acres of the state’s 9 million total.
“Beyond the prohibition areas, we limit atrazine use in the rest of the state, requiring lower application rates than the federal label does and restricting the times when atrazine may be applied,” Cosh said.
So if DATCP feels it’s necessary to impose such strict regulations, and even those have apparently not been enough to protect every consumer, should other state and federal regulators be compelled to do the same?
“We don’t have statistics for every state,” said Cosh, regarding the national prevalence of atrazine. “The EPA gathers info about pesticides in general from all the states annually and publishes it in the POINTS [pesticides of interest] database. This report suggests that atrazine is a concern in 60 percent of all states in the U.S., but the degree of concern is likely related to the types of crops that predominate in any given state.”
There’s reason to believe that Wisconsin’s stricter stance on atrazine is a good model for other states that decide federal regulations are not enough. In a PhD dissertation for the University of California, Santa Cruz on the environmental impacts of atrazine, Joanna Ory lauded Wisconsin’s stance. She compared over 3,000 samples from 610 wells and found that atrazine contamination decreased steadily from 1992 to 2013, from an average of 3 ppb to .67 ppb.
“The atrazine rule in Wisconsin is a policy that has contributed towards strong improvements in water quality protection, and it can be seen as a first step in the types of policies that are needed nationwide,” she wrote.
According to WCIJ, the EPA’s most recent look at the dangers of atrazine has led to a recommended 3.4 ppb maximum in surface waters, closer to the DATCP limit than its current rule. The possibility of a stricter limit is still being debated, with agricultural groups opposed to its adoption.
Opponents argue that if atrazine is limited it will not only hurt farmers’ ability to protect their crops, but also encourage the use of even harsher chemicals that could end up in water sources.
It’s hard to know if a chain reaction for limiting atrazine would make drinking water quality worse, harder still to say whether or not that means it shouldn’t be done. Ory’s research found that decreased atrazine use has led to increased use of other herbicides and the jury is still out on their effects on human health. In her dissertation, she draws the natural conclusion that only stronger pesticide regulations across the board could guarantee safer water.
“A holistic policy approach that sets overall health standards for total pesticides in water as well as a plan for reducing overall pesticide use would be the strongest way forward in ensuring cleaner environments and lower human health risk from agriculture,” she wrote.
Image credit: "Corn field," Oregon Department of Agriculture © 2009, used under an Attribution 2.0 Generic license: http://creativecommons.org/licenses/by/2.0