Officials in Michigan Warn of PFAS Contamination in Fish and Wildlife


Michigan health officials have issued a warning against eating more than one serving of Lake Superior rainbow smelt a month after Wisconsin researchers discovered elevated levels of PFAS “forever chemicals” in fish taken near the Apostle Islands.

Data from the Michigan Department of Environment, Great Lakes, and Energy – Water Resources Division (EGLE-WRD) showed that PFAS contamination levels in 2,841 fish caught in the state. PFAS is short for toxic per-and-poly fluoroalkyl substances.

In Wisconsin, the fish tested had high levels of a PFAS compound known as PFOS, or perfluorooctanesulfonic acid, in their tissue. Research has linked the compound, which was once a key component in Scotchgard and other stain and water repellents, to various human disorders, including developmental problems, hormonal and immunity problems, fertility issues, and cancer.

Lake Superior Fish Is a Dietary Staple

As per the advisory, adults should eat no more than 8 ounces each month, and children should eat no more than 2 or 4 ounces, according to an announcement from the Michigan Department of Health and Human Services. The advisory comes just weeks before the start of the spring smelt run, a highly anticipated event for anglers who catch the fish in nets as they swim into Great Lakes tributaries to spawn.

The news was another blow to recreational and subsistence anglers who have already been told to limit or avoid eating fish from multiple water bodies across the state due to contamination from PFAS “forever chemicals.” It’s particularly alarming for Upper Peninsula Native American anglers, who smelt and other Lake Superior fish is a dietary staple. Most members of the Keweenaw Bay Indian Community eat far more than 8 ounces of smelt during the spring run, said Chris Swartz, the tribe’s president. Swartz said:

“We’re a fishing tribe […] that’s our way of life and the main part of our diet.”

Newfound PFAS contamination, longstanding mercury contamination, and ecosystem shifts have caused some Great Lakes fish populations to struggle, Swartz said. 

“Our way of life is being diminished as we talk.”

Do Not Eat Advisories

88% of the fish had results above 260 parts per trillion (ppt), the minimum levels reported in the study. 260 ppt is more than three times higher than the EPA’s Lifetime Health Advisory of 70 ppt for drinking water. The fish averaged 92,641 ppt of PFOS. The state issues “Do Not Eat” advisories for fish that top 300,000 ppt of PFOS, although Proud Lake is an exception. The officials said: 

“It’s OK to a eat Smallmouth Bass like this containing 307,000 parts per trillion of PFOS from Proud Lake in Michigan, while drinking water cannot exceed 16 parts per trillion of the toxins.”

The data summarizes the analyses of the edible portion samples of the fish in the EGLE database. Twenty-three species from 178 locations were analyzed. Michigan has measured contaminants in over 20,000 fish tissue samples collected since 1980. PFAS is studied because they are known to exhibit high bioaccumulation potential in fish tissue. The tiniest amounts of PFAS in surface water can result in fish tissue concentrations that pose a human or wildlife health risk.

Poisoned Lakes to Fish While There Is No Signage

PFAS is among the most toxic chemicals ever produced. It’s responsible for immeasurable death and suffering from human ingestion at microscopic levels. The substance bioaccumulates in fish and in humans, and it takes nearly forever to go away. The military, private companies and the public recklessly use the substances and discard them into the environment. The EPA still refuses to regulate the stuff.

Michigan’s fish advisories are not mandatory. They are only guidelines to help people make safer choices. Critics claim these advisories are poorly marketed while there are many areas where anglers approach poisoned lakes to fish while there is no signage. 

The advisories are somewhat like the federal Cigarette Labeling and Advertising Act of 1965, mandating that the warning “Caution: Cigarette Smoking May Be Hazardous to Your Health” be placed on one of the side panels of each cigarette package. 

In the case of hazardous fish, however, the federal government has not issued warnings on fish containing high levels of PFAS, and most states have not posted fish advisories for PFAS.

Limiting or Altogether Avoiding

High levels of the “forever chemicals” in Oscoda Township, the result of firefighting foam used on the now-shuttered Wurtsmith Air Force Base, make the Lake Huron community one of Michigan’s most contaminated sites. Along with deer, state officials warn against eating fish and any other aquatic or semi-aquatic animal living in the marsh.

Hock now fishes only catch-and-release and has come to terms with the health risk he takes by hunting. But he worries about what the chemicals are doing to the animals in Clark’s Marsh and the many other locations where state health officials recommend limiting or altogether avoiding meals of PFAS-tainted fish.

Years into Michigan’s PFAS contamination crisis, such answers remain scarce. But the state’s experience with widespread PFAS contamination has made it an early research laboratory into how the chemicals spread through the environment and what that does to the species that live anywhere near the toxic stew. 

Everything from Fish to Sediment and Algae

Research has linked PFAS exposure to developmental problems, hormonal and immunity problems, fertility issues, and cancer in humans. That’s why regulators warn against drinking water or eating food tainted with the chemicals. Effects on plants and animals are far less well-understood, leaving us without a clear picture of whether or how PFAS contamination could harm species that humans depend upon for food, clean water, crop pollination, and other benefits. 

The quest for information started in Clark’s Marsh, where a Purdue University research team has been working since 2019 to learn more about how PFAS moves through the environment. Could the sediment be a continuing source of contamination even after PFAS stops flowing in the water? Does PFAS contamination transfer from species to species as it moves through the food chain? And, importantly, what kind of harm do exposed species experience? 

Last summer, researchers from Purdue ecology professor Jason Hoverman’s lab visited Clark’s marsh, a large wetland just south of the Air Force base, to collect samples of everything from fish to sediment and algae. From there, they’ll use models to map out how various species are being exposed and whether the toxins can “transfer out” of the aquatic system by, say, a migratory bird eating a fish from Clark’s marsh or an aquatic insect leaving the water.


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