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Illinois Stops Testing Fish for DDT

Lance Merry
Missouri Department of Conservation

Illinois will discontinue testing freshwater fish for pesticides like DDT.

That’s because the chemicals, called organochlorine pesticides, are no longer being found at unsafe levels in the state’s waterways.

Brian Koch is the manager of the environmental toxicology program at the Illinois Department of Public Health.

“We really haven’t been finding them at levels of concern for decades. We’ve been monitoring for these pesticides for nearly 50 years," he said. "It’s been over 30 years since we detected these pesticides at a level that would warrant a ‘do not eat’ advisory.”

Organochlorine pesticides were banned in the U.S. in 1972. Illinois began testing for them in 1974. Due to the long half-life of the pesticides, the chemicals can build up in fish tissue, and pose a risk to humans who eat those fish.

“It takes many years for them to break down. Once they get into the aquatic environment, they tend to be found in the sediment, which means bottom-feeding fish, such as carp and channel catfish, tend to be at greater risk," Koch said. "In Illinois, we found that fish contamination was a problem mainly in large reservoirs and large rivers."

"The human health effects were mainly related to the liver, some of these also were known to be carcinogens, so there was a cancer risk.”

Koch says the state still might test fish for these pesticides sporadically. The decision won’t affect the state’s testing for other contaminants, like mercury.

Rachel graduated from Michigan State University's J-School and has a background in broadcast and environmental journalism. Before WVIK, she worked for WKAR Public Media, Great Lakes Now, and more. In her free time, she likes to cook, hike, and hang out with her cat.