EPA Finds Widely-Used Weed Killer Could Threaten Animals


Atrazine is the second-most widely used herbicide in the United States. Manufactured by the chemical giant Syngenta, farmers have sprayed, on average, 70 million pounds of the weed killer on cropland across the country for the last twenty years. Half of the corn grown in the United States — some tens of millions of acres — is treated with atrazine.

Anyone who cares about wildlife, people and the environment should be deeply troubled by this finding

The sheer volume of atrazine applied to United States cropland has made it an easy target for the scientific and environmental communities, who have long worried that atrazine could be linked to birth defects in humans and contamination of groundwater. Now, a new EPA draft assessment released Thursday, looking at ecological risked posed by atrazine, backs up those claims. The assessment found that heavy use of the herbicide could be dangerous to fish, mammals, birds, reptiles, and plants.

“Anyone who cares about wildlife, people and the environment should be deeply troubled by this finding,” Nathan Donley, a scientist with the Center for Biological Diversity, said in a press statement. “When the government’s own scientists say there’s enough atrazine in streams and rivers right now to kill frogs and other imperiled wildlife, we should be worried.”


The EPA’s draft assessment — which looked at toxicity studies, 20 years of water monitoring, and aquatic exposure models — is hardly the first scientific assessment to link atrazine to dangerous health impacts for both animals and humans. Previous studies have linked the chemical to delayed timing of menopause, reproductive problems for men, birth defects, and cancer. Tyrone Hayes, a biologist at the University of California, Berkeley, has been publishing studies on the impacts of atrazine for years, and has long argued that the chemical can act as an endocrine disruptor, impeding the sexual development of amphibians like frogs. Following the publication of his first study into atrazine — which was actually funded by Syngenta — Hayes accused the company of trying to strong-arm his research, saying it organized a public relations campaign to discredit his reputation as a scientist.

Hayes is not Syngenta’s only vocal adversary in the debate over the safety of atrazine. A 2009 New York Times investigation found that in some towns — especially those in the Midwestern United States, where concentration of atrazine use is highest — the concentration of atrazine in drinking water could be dangerously high. These instances of contaminated water led 43 water systems across six Midwestern states to file a lawsuit against Syngenta, hoping to force the company to pay for removing the chemical from their water supplies. In 2012, Syngenta settled with the water utilities in the Midwest for $105 million. By that time, the lawsuit had expanded to cover 2,000 utilities serving more than 52 million Americans.

In 2010, the EPA began reviewing atrazine, convening panels of independent scientists to examine the chemical. Technically, the EPA is supposed to review all registered pesticides at least every fifteen years, to make sure that regulations still match up with current information about the pesticide. But EPA regulations, especially when it comes to chemicals, are tricky. As the New Yorker profile of Hayes points out, the EPA depends largely on a system of cost-benefit analyses when deciding whether or not to regulate a chemical — and because it’s so tricky to put a price on ecological impacts, or even human health impacts, it can be difficult for the EPA to make a case that a specific chemical needs to be regulated.

The draft assessment released Thursday, if finalized, would be a major step towards regulating atrazine at a federal level (atrazine is already banned in the European Union, over concerns that it could contaminate groundwater). That would be a big win for environmentalists, and a serious blow to agricultural groups and the chemical industry, which have labeled the EPA study as error-ridden.

3 Pesticides Are Putting Nearly All U.S. Endangered Species At RiskClimate by CREDIT: AP Photo/Wilfredo Lee, File A few widely-used pesticides have the ability to harm nearly all the…“We’re troubled the draft assessment discounted several rigorous, high-quality scientific studies and didn’t adhere to EPA’s own high standards,” Marian Stypa, head of product development for Syngenta in North America, said in a press statement. “The draft report erroneously and improperly estimated atrazine’s levels of concern for birds, fish, mammals and aquatic communities that are not supported by science.”


The EPA, however, stands by the science used in its draft assessment, telling Politico that it “considered all available data on atrazine — including studies submitted to the agency in support of registration, as well as scientific open literature.”

The assessment will be open for public comment after it is published in the Federal Register, which the EPA plans to do soon. The EPA will then consider public comments and will convene another scientific advisory panel sometime in 2017 before finalizing the rule.

Atrazine is not the first widely-used agricultural chemical to come under scrutiny for its potential impacts on public and environmental health. Last year, the World Health Organization found that glyphosate — the most popular weedkiller in the world — was “probably carcinogenic to humans.” Shortly thereafter, the EPA placed restrictions on the chemical, requiring producers that use it to come up with a weed resistance management plan.