Atrazine: What Farmers Might Not Know

April 26, 2011 By Stephen Peyton, Guest Commentary

This is the sixth of an eight-part series on environmental policy in conjunction with Macalester College's Environmental Studies Department.

Within the last decade, University of California, Berkeley scientists have done a series of tests using a product that chemically castrated 75 percent of male frogs and turned 10 percent into females.

It would seem a chemical linked to these types of outcomes should either be banned or only utilized in top-secret military operations. However, this chemical is all around us: it’s used to make some of the food we eat and it’s in water we drink.

The chemical is called atrazine, a widely used herbicide in Minnesota, especially among corn growers. Several studies suggest that exposure to atrazine in drinking water has been linked to abnormal infant development, low birth weights, and decreased fertility in humans.

Research by Theo Colborn, esteemed author of Our Stolen Future, has discovered that hormone-disrupting chemicals like atrazine affect children in critical stages of development much more adversely than adults. Unborn babies are especially vulnerable while still in the womb.

Animals exposed to atrazine before birth may become more vulnerable to cancers. Atrazine has been known to inhibit testosterone production and increase rates of prostate cancer in rats. It also causes hormone imbalances in exposed rats’ female offspring. According to Tyrone B. Hayes at the University of California Berkeley, atrazine is affecting populations two generations down.

Even though several scientists have recently shown links to negative health effects in humans, Minnesota and federal officials have been slow to ban or issue new health warnings for this substance.

Atrazine’s a popular weed-killer because it’s relatively inexpensive and highly effective. Economically, it is a great product. Unfortunately, many farmers do not realize the adverse effects associated with it.

More than six years ago, the European Union banned atrazine. However, its system for banning substance is much more stringent. Last year, Minnesota Congressman Keith Ellison introduced a bill that would ban atrazine in the U.S. On the state level, Minnesota made an attempt to ban the weed-killer in 2005, but that legislation died.

While there are health concerns and warnings for people who work directly with the chemical, Atrazine’s main cause for concern is its presence in groundwater. While Missouri, Nebraska, Iowa, Ohio, and Maryland, have significantly higher levels, more than eight percent of Minnesotans are exposed to Atrazine in their drinking water, according to a 2009 New York Times article.

Even more disconcerting is atrazine’s long term impact on farming practices. Although the product is very effective at killing weeds, no herbicide is 100% effective. Even after spraying, a small atrazine-resistant population of the weed is likely to survive and repopulate. Farmers are then faced with a more powerful weed and the only method of control is more spraying. This “treadmill” could lead to higher and higher concentrations of toxic chemicals in groundwater.

Part of the controversy around atrazine is that the EPA has been saying its 2003 regulations governing it are adequate to protect human health. “Doses of atrazine coming through people’s taps are safe,” the New York Times attributed to official EPA statements. However, researchers criticize the EPA for weak regulations. Furthermore, new research also shows that even in EPA approved concentrations, atrazine can be harmful to humans, especially the unborn, the Times article points out. The EPA is now re-examining its standards regarding the weed killer in light of several reports linking it to serious health concerns.

Complicating the matter for Minnesota ban advocates is that several state agencies, including the Department of Agriculture, declined to change the regulations governing Atrazine use. However, they did leave the door open for stricter rules when issuing their November 2010 ruling. “Elements of atrazine registration and regulation may need revision if emerging science or EPA evaluations reach new conclusions about human health and environmental impacts of atrazine.”

Many Minnesota environmental groups disagreed with the decision and call for stricter atrazine regulations. The National Research Defense Council has identified unacceptably high spikes in atrazine concentrations in the Midwest during early summer months due to its farm application.

Farmers have been using this chemical for half a century under a regulatory framework that led them to believe it was safe to humans. Now that there is more research available suggesting that might not be the case, it’s time to reexamine our use of this product.

With well-respected, peer-reviewed researchers suggesting a list of hazards from this potent chemical, why are we even risking the long-term health impacts? Shouldn’t we stop using this until the EPA reviews the research, conducts further testing, and makes a recommendation?

Short of even a temporary ban, more funding needs to be made available for local communities to more adequately test their water supplies. In the meantime, consumers can send a message by purchasing foods that don’t use harmful herbicides or pesticides.

Stephen Peyton is a Macalester College Environmental Studies major.

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