A new study has found that consuming a single fish from the Great Lakes is equal to drinking a month's worth of water contaminated with high levels of "forever chemicals."
The study, which was peer-reviewed and published in the Environmental Research Journal, found that PFAS are widely detected in freshwater fish across the United States.
PFAS, or per- and polyfluoroalkyl substances, are used widely in consumer products ranging from nonstick cookware and water-repellent sports gear to stain-resistant carpets. They're also a key ingredient in fire-extinguishing foams. They can accumulate and persist in the human body for long periods, and exposure may lead to cancer and other health problems, the Environmental Protection Agency reports.
According to the study, "even infrequent freshwater fish consumption can increase serum PFOS levels," also known as perfluorooctane sulfonic acid levels.
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One fish serving was reported to be "equivalent to drinking water for a month at 48 [parts per trillion] PFOS." By comparison, the EPA issued new guidance last summer stating the concentration of chemicals in drinking water should not exceed 0.02 parts per trillion for PFOS, saying the chemicals are dangerous even at undetectable levels.
PFAS compounds have been found in all five Great Lakes — Erie, Huron, Michigan, Ontario and Superior. They don't degrade naturally in the environment and move freely in water, unlike contaminants such as PCBs that stick in sediments, Christy Remucal, associate professor of civil and environmental engineering at the University of Wisconsin, told the Associated Press earlier this month after a similar study found high PFAS levels in Green Bay.
There, a large plume of toxic chemicals produced by a plant that manufactures firefighting foam seeped through groundwater to Lake Michigan's Green Bay, scientists said.
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Groundwater and streams near the Tyco Fire Products in Marinette, Wisconsin, are contaminated with foam from the plant's testing facility.
University of Wisconsin researchers have traced movement of the chemicals in nearby groundwater and streams. In a report published last week, they said a plume had made its way into Green Bay, which extends 120 miles (193 kilometers) along northeastern Wisconsin and the south coast of Michigan's Upper Peninsula.
Water samples suggest the plume is about 2.49 miles (4 kilometers) wide but it's unknown how far it extends along the bay, said Remucal.
“A lot of PFAS from that source is going into Lake Michigan and it will be hard to contain," Remucal said in an interview. “It's really dispersed, hard to capture and treat.”
Scientists detected 17 different PFAS chemicals in the bay, one of the largest on the Great Lakes.
Thousands of different PFAS compounds have been manufactured since the 1940s.
They also far exceed the 70 parts per trillion that the U.S. Environmental Protection Agency had established as a drinking water health risk threshold for two common PFAS compounds, known as PFOS and PFOA.
Wisconsin's attorney general last year sued Tyco and Johnson Controls, with which it merged in 2016, over PFAS contamination in the Marinette area.
Tyco said in a statement it welcomed the Green Bay study, which was funded by the Wisconsin Sea Grant College Program, and that it had invested “tens of millions of dollars” to address the Marinette pollution. Those efforts include an “expansive” groundwater treatment system, soil excavation and working to deliver “long-term drinking water solutions” in the area.
Much remains unknown about how PFAS chemicals affect Great Lakes fish, a topic the Michigan State University's Center for PFAS Research is exploring, Dan Jones, associate director of the center said.
“We know that these compounds get taken up by things that live in the lakes ... including particular fish that we humans consume,” he said. “But we don't really know as much as we'd like to about which fish they accumulate in and why, and whether it's different for different compounds.”
Meanwhile, the Wisconsin Department of Natural Resources and the state's health department in October issued "consumption advisories" for several fish species in Castle Rock Lake and Lake Mohawksin, both segments of the Wisconsin River, due to elevated levels of PFOS.
Illinois' Department of Natural Resources also tracks chemical levels in freshwater fish across the state, issuing advisories of how often certain species should be consumed based on their chemical levels. But PFAS were not previously included in the testing efforts.
In 2021, the Illinois EPA "requested that IDNR conduct additional fish sampling at 17 locations where per-and polyfluoroalkyl substances (PFAS) were previously found," the department stated.
"PFOS will be added to future routine monitoring," the agency said at the time.
In addition, the U.S. EPA's Great Lakes Restoration Initiative gave the Illinois EPA a grant to purchase equipment "capable of analyzing PFOS in fish tissue." As part of that agreement, the IDNR was slated to collect fish samples from Lake Michigan through 2023 "to determine levels of PFOS in sport fish taken from Lake Michigan."
