SPRINGFIELD, Ill. (WMBD) – The state will stop testing for organochlorine pesticides, such as DDT, in fish from Illinois lakes and rivers.

The Illinois Department of Public Health, in conjunction with the Illinois Environmental Protection Agency and the Illinois Department of Agriculture, made the announcement on Monday and noted such chemicals have been banned for decades.

Illinois has been testing for them since 1974 because they are “environmentally persistent” and can build up in the tissue of fish and other animals. But as levels have diminished to nearly zero over the past 50 years, the agencies opted to stop testing.

Testing for other contaminants in fish, including methylmercury and polychlorinated biphenyls (PCBs), will not be affected by these changes.

“The progress made in improving the safety of fish found in Illinois waterways is an incredible victory for public health and a testament to the success of sensible health and safety regulations,” said IDPH Director Sameer Vohra. “Banning dangerous pesticides like DDT has made our water cleaner, our food safer, and our state healthier.”

DDT and other organochlorine pesticides were in widespread use across America dating back to the 1940s. Concerns about the impact of DDT on wildlife and on people led to its ban for agricultural use in the U.S. in 1972 with bans on other organochlorine pesticides following a decade later.

In the early 1970s, the state implemented the Illinois Fish Contaminant Monitoring Program, a protocol of testing fish from the state’s lakes, rivers, and streams. Lake Michigan is sampled annually, with samples drawn from rivers and large streams every five years, along with periodic testing of other public lakes. The testing measures whether fish samples contain pesticides, metals, or other dangerous chemicals at a level that would render them unsafe to eat.

In its early days, testing from state waterways indicated concerning levels of DDT, chlordane, and dieldrin in bottom feeding fish such as carp and catfish. Levels of chlordane were detected at rates making the fish unsafe to eat until the mid-1970s; DDT was found at unsafe levels until the early 1980s. Dieldrin, another organochlorine pesticide, was detected in levels deemed to be unsafe to eat as recently as the early 1990s.

Since then, however, the pesticides are no longer found in unsafe amounts. With those chemicals no longer in use, continuation of the testing program for those pesticides is no longer necessary, saving both time and money.