The battle over the use of atrazine is largely contained between the Midwest farmers versus the Environmental Protection Agency (EPA). But its impact is sending ripples throughout our environment and water supply.

Anyone with a garden knows that weeds are the peskiest of plants. Midwest farmers—like the corn famers in Iowa and Kansas—rely heavily on the herbicide called atrazine to control broadleaf and grassy weeds.

The farming industry journal Farm Futures reports that: “atrazine increases crop yields and enables no-till farming and conservation tillage, which help keep aquatic systems healthy by dramatically reducing soil runoff into rivers and streams.” (

However, in June, the EPA released an ecological risk assessment published in the Federal Register ( that said atrazine “has a high probability of impacting aquatic plant community primary productivity, structure and function.”

While this herbicide isn’t commonly available to the general population it’s prominence in cornfields has the potential to contaminate drinking water by ending up in streams, rivers, lakes, and wells.

Common problems cited in the EPA report are water drift and runoff with chemical concentrations in water at or above 5 grams per liter or a 60-day average of 3.4 grams per liter.

According to The Center for Disease Control and Prevention, ( “atrazine may affect pregnant women by causing their babies to grow more slowly than normal. Birth defects and liver, kidney, and heart damage has been seen in animals exposed to high levels of atrazine.”

Most of the studies of damage by atrazine have been observed with animals that were left with permanent damage to the liver, kidneys, and the heart after exposure to the chemical.

In humans atrazine is part of a group of toxins listed as endocrine-disrupting chemical. These chemicals have been studied worldwide. The World Health Organization has issued warning about how these chemicals can alter reproductive functions; increase the chances of developing breast cancer, abnormal growth patterns and neurodevelopmental delays in children, as well as changes in immune function. (

Manufactured by agro-chemical giant Syngenta, atrazine is banned in Europe. While this herbicide isn’t commonly available to the general population it is one of the most widely-used used herbicides in US agriculture.

Environmental and food advocates are applauding the EPA report, citing it as an acknowledgment of the dangers posed by atrazine. Many are calling for an all-out ban on its use. But since the release of the report farmers have pushed back.

The Cedar Valley Business Monthly, reported: “the Iowa Corn Growers cited a 2012 study from the University of Chicago that said a ban on atrazine would cost corn growers up to $59 per acre more in input costs.”

The article also cited Iowa Agriculture Secretary Bill Northey: “The stakes are high for Iowa farmers. It is widely used across many crops because it is one of the most reliable herbicides on the market in managing tough-to-control weeds and has helped us increase yields,” he said. “It has allowed farmers to use less chemicals, making fewer passes in the field which means fewer carbon emissions.”

Media coverage of the EPA report has triggered many articles that point to the wide-spread evidence of harm, including this one from Mother Jones. (

Journalist Tom Philpott spoke to the integrative biologist from the University of California-Berkeley, Tyrone Hayes. Hayes was the one who discovered that “miniscule amounts of the chemical can trigger sex changes in frogs”.

The EPA paper cited several studies by Hayes as evidence for its conclusion.

Philpott spoke to him about what’s next in terms of banning the chemical: “The science has been settled for a long time,” Hayes told me. “Now it’s politics and economics.”

While the EPA is aware of the dangerous environmental consequences posed by atrazine, the assessment report won’t be finalized until 2017. That means the next administration will decide if any regulatory action toward a permanent ban or more stringent rules for its use will happen.