Farmers began phasing out the use of a particular pesticide long before a federal judge recently banned it. But chlorpyrifos could still have some long-term effects in Iowa.
Earlier this month, a federal judge ordered the U.S. Environmental Protection Agency to ban the agricultural use of chlorpyrifos within 60 days. The ruling comes after the Trump Adminstration decided to not pull it from the market in 2017, despite evidence it can pose a health risk.
Chlorpyrifos is an organophosphate used on corn, soybeans, wheat, alfalfa, as well as in orchards. The pesticide, which is also known by its trade names Dursban and Lorsban, targets the nervous systems of insects, but some researchers have also linked it to nervous system damage in humans, as well as developmental issues in fetuses and young children.
According to an analysis by the U.S. Geological Survey, chlorpyrifos is more popular in the Upper Midwest than virtually any other region in the country. Heavier applications are especially concentrated in northwest Iowa, southwest Minnesota and eastern North Dakota, where farmers are using upwards of 5.5 pounds per square mile.
But the use of the insecticide pales in comparison to the use of far more popular pesticides such as glyphosate, which Iowa farmers apply at rates of more than 88 pounds per square mile. And overall use of chlorpyrifos has been on the decline since 1994, long before the recent court ruling.
Still, one Iowa researcher said even after the insecticide is pulled from the market, there's reason to believe farmers in the state may develop long-term health effects. According to Iowa's Center for Agricultural Health and Safety, or I-CASH, in 2012 chlorpyrifos was the most common insecticide sprayed on Iowa soybeans. I-CASH's Ralph Altmeier said some farmers may already be noticing nervous damage from years of low-level exposure.
"My father would've used some of these chemicals like Lorsban, the insecticide for corn. He would've used that for decades. In his older age he had trouble with his nerves," Altmeier said. "His toes would burn."
Altmeier sees a connection between his father's decades of use of chlorpyrifos and his nerve damage.
"That’s perhaps a result of chronic exposure to this. And that’s not life-threatening, but it was uncomfortable for him at times. So there could be some long-term chronic effects that are just showing up now," Altmeier said.
Altmeier says it can be difficult to draw a direct causal link between pesticide exposure and later health conditions, but he said he'll be looking for signs of adverse health impacts in himself as well. He also used chlorpyrifos in his decades-long farming career.
“I wonder what I’ll experience in another 10 or 20 years because I used some of those same chemicals," Altmeier said. "Some of that neurotoxin effect is cumulative and non-reversible.”