PFAS levels are declining in Great Lakes fish, new research shows

A new study offers hope for PFAS-tainted Great Lakes fish: Contamination levels are declining
The trend stems from manufacturers phasing out some PFAS compounds in the mid-2000s
The findings come amid uncertainty about federal PFAS oversight as the Trump administration rolls back regulations

In the years since Michigan’s PFAS crisis became public knowledge, widespread contamination has prompted a growing list of “do not eat” advisories in waterways across the state.

But a study published this month in the Journal of Great Lakes Research offers hope that, one day, the fish could be safe to eat again.

The study was conducted by researchers in the former US Environmental Protection Agency Office of Research and Development, which the Trump administration has since dismantled amid a broad push to curtail federal oversight and loosen regulations on a host of chemicals, including PFAS.

Using decades’ worth of archived lake trout and walleye samples originally collected to track older pollutants like mercury and PCBs, scientists discovered PFAS levels in Great Lakes fish have declined significantly since the late 2000s, when manufacturers began phasing out once-common compounds like PFOS and PFOA amid growing regulatory pressure.

“The ecosystem responded very quickly to these changes in industrial production,” said Sarah Balgooyen, a lead author of the study and former EPA chemist who is now a researcher at the Colorado School of Mines.

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A growing body of research has linked certain PFAS (an acronym for a class of thousands of chemicals known as per- and polyfluoroalkyl substances) to cancer, thyroid problems and developmental, fertility and immunity challenges.

The research team tested for 45 compounds, using fish taken from the Great Lakes between 1975 and 2020. They found that average contamination levels by 2020 had reached their lowest since the 1980s.

In Lake Erie, for example, PFAS levels in the freeze-dried tissue samples peaked at close to 450 nanograms per gram in 2005 but were closer to 50 nanograms per gram in 2020. In Lake Michigan, levels reached a high of about 150 nanograms per gram in 2010 before drifting down to about 80 nanograms per gram in 2020.

“We hope to see that trend continue,” Balgooyen said.

That’s welcome news to Chris Matteson, a 76-year-old from Muskegon who has been fishing in the Great Lakes since the days when factories lined the shore, spewing effluent so foul that, “if you could see a foot into the water, that was pretty good.”

“I’ve been through a lot of fish warnings,” Matteson said.

A chart showing declining levels of PFAS in Great Lakes fish — Researchers used archived fish tissue to develop a historical record of PFAS levels in Great Lakes trout and walleye, finding that levels have significantly declined since manufacturers began phasing out some PFAS compounds. (Courtesy of Sarah Balgooyen)

Although PFAS manufacturers have known their products are toxic since at least the 1970s, the public wouldn’t learn until decades later. Unregulated use of the so-called “forever chemicals” allowed them to escape into the environment, poisoning drinking water and embedding in the bodies of humans, fish and wildlife.

Only in recent years — after a series of contamination scandals — have state and federal governments begun regulating PFAS and investigating the extent of the pollution.

In 98 Michigan water bodies, some fish species are so full of PFAS that state health officials say it’s not safe to eat them. Health advisories in hundreds more water bodies call for limiting meals to anywhere from 16 servings a month to six a year.

Michigan Department of Health and Human Services spokesperson Lynn Sutfin said agency staff are reviewing the study.

For now, she said, “our advice for anglers remains the same: To learn how to choose safer fish to eat, follow the Eat Safe Fish Guides.”

Find out whether your local fishing spot is affected here.

Gary Ankley, a former EPA research toxicologist and coauthor on the study, said the declining PFAS levels are encouraging. But there is no way to know how low PFAS levels will ultimately fall.

Known as “forever chemicals” because they don’t break down readily in the environment, some amount of PFAS will remain in the lake indefinitely, Ankley predicted.

Balgooyen cautioned that the study offers only a partial picture of PFAS risks in the lakes.

While manufacturers have largely stopped using the so-called “long-chain” PFAS compounds that tend to bioaccumulate in fish, many have switched to new “short-chain” compounds that do not.

The health risks of those newer compounds have not been well-studied.

“We’re seeing decreases in these compounds that we know are harmful, which is great,” Balgooyen said. “But there’s still this unknown component of the replacement chemicals.”

Citing evidence that PFAS is more toxic than previously thought, state and federal regulators in recent years have lowered allowable PFAS levels in drinking water and taken other steps to discourage the chemicals’ use.

Seeking to make the EPA more business-friendly, the Trump administration has reversed some of those actions, announcing plans to loosen PFAS drinking water standards and requirements for manufacturers to report their PFAS use.

EPA Administrator Lee Zeldin called those “commonsense” changes that would lower costs for industries and water providers while still protecting the public.

But Matteson, the Muskegon fisherman, views the administration’s loosening of environmental regulations differently.

“The companies will go back to the easiest, cheapest way to do anything,” he said. “Most likely, it isn’t environmentally friendly.”