After decades of diligent monitoring, the state of Illinois has decided to discontinue testing fish in its lakes and streams for organochlorine pesticides, notably the infamous DDT. This decision comes as a result of reassuring findings indicating that these banned chemicals, which were once pervasive in the environment, no longer pose a significant threat to aquatic ecosystems.
The state of Illinois initiated fish testing for organochlorine pesticides in the 1970s, shortly after the well-known pesticide DDT was banned in the United States. Prior to this ban, organochlorine pesticides had been extensively utilized since the 1940s.
The Illinois Department of Public Health (IDPH) explained in a news release that the testing was initially undertaken because these chemicals exhibited high environmental persistence, accumulating in the tissues of fish and other wildlife.
Brian Koch, a representative from IDPH, emphasized that levels of these chemicals have not reached hazardous concentrations for over three decades. “It’s been over thirty years since we’ve detected these pesticides at levels that would warrant a Do-Not-Eat advisory for Illinois fish,” Koch stated. “So really, there’s little chance that these pesticides are going to be detected at levels of concern in the near future, if at all.”
Historical testing revealed concerning levels of DDT, chlordane, and dieldrin in bottom-feeding fish like carp and catfish. However, over time, levels of all three chemicals steadily decreased and reached safe thresholds. Dieldrin was the last to fall below unsafe levels in Illinois fish, a milestone achieved sometime in the 1990s.
Despite ceasing organochlorine pesticide testing, Illinois continues to monitor fish for other contaminants, such as mercury and polychlorinated biphenyls (PCBs). Additionally, the Illinois Environmental Protection Agency is gearing up to assess per- and polyfluorinated alkyl substances (PFAS), commonly known as “forever chemicals,” which are prevalent in various products.
Brian Koch remarked on the significance of PFAS testing, stating, “It’s really a hot-button issue throughout the nation right now.” He added, “Illinois EPA has recently received some laboratory equipment so they can go ahead and actually analyze PFAS in fish tissues.”
The Illinois Department of Public Health maintains an advisory page on its website, offering guidance on the safety of consuming fish from different lakes and streams across the state in light of chemical pollution concerns.
