Researchers say insecticides called neonicotinoids, which are used often in corn and soy fields, are leaching into Midwestern waterways and are not only contributing to an alarming decline of bee colonies, they are potentially harming marine life.
The European Union placed a moratorium on the chemicals’use and environmentalists are calling on corn farmers to do the same.
In a study published July 24, researchers at the U.S. Geological Survey found that these chemicals are also leaching into streams and rivers in the Midwest —including the Missouri and Mississippi rivers. And that could be bad news for aquatic life in the region, the scientists say.
"We did the study because the use of the neonicotinoids has been increasing dramatically, especially in the Midwest," Kathryn Kuivila, an environmental organic chemist with the USGS, told National Public Radio.
Since these chemicals are highly water soluble, it made sense to investigate whether they were present in the region's streams and rivers, Kuivila said.
These pesticides coat the seeds of many agricultural crops, but still end up in the soil and then in the water that runs off farms.
Runoff transports the chemicals from the field to streams and rivers, and since they don't break down easily in the environment, they can stick around in these bodies of water for long periods of time, the USGS study notes.
And while they're not especially toxic to humans, they can harm a wide variety of insects. At certain concentrations, they can hurt other animals as well.
Recent research suggests that lower levels of these chemicals could also be toxic to aquatic life —including aquatic insects. And a study published in Nature found a correlation between these insecticides and declining bird populations, perhaps because the chemicals are killing off insects that the birds eat, or because the birds are eating insecticide-coated seeds.
The National Corn Growers Association says the chemicals are “critically important”to growers because they protect seeds from disease and pests.
Corn ethanol production has increased the amount of corn grown in the United States since 2006.
Researchers are increasingly pointing to the chemicals used in the increased corn production as culprits for the decline in honey bees, which have historically been crucial plant pollinators.
Beekeepers, environmental and consumer groups took a historic step filing suit in federal court against the Environmental Protection Agency over the government permitting the use of the pesticides, according to the Washington Times. The suit didn’t seek money, but asked the EPA to follow the law.