For individuals that enjoy a meal wild-caught freshwater fish after catching them in a Minnesota or Wisconsin body of water, a new study suggests those fish might contain high levels of ' forever chemicals'.

A study published in the most recent edition of Environmental Research (via The Hill) points to high levels of contamination in samples of wild freshwater fish across the United States - including inland bodies of water in Minnesota and Wisconsin, along with around the Great Lakes.

The study's findings point to the average single serving of fish containing the same amount of PFAs or "forever chemicals" one might be exposed to by drinking heavily contaminated water for an entire month. The average amount of contamination reportedly found is 2,400 times higher than the EPA's recommended exposure levels for humans.

What are PFAs?

The EPA describes PFAs, or polyfluoroalkyl substances, as chemicals that break down very slowly over time. These manmade chemicals have been used in a variety of industrial and consumer products and processes since the 1940s. Some uses include in certain types of firefighting foam, packaging, water-repellant clothing, stain-resistant fabrics, carpet, nonstick cookware, and other items.

What are the health effects of PFAs?

The CDC's Agency for Toxic Substances and Disease Registry (ATSDR) explains that PFAs could lead to a number of health issues. They point out that different studies have pointed to different types of impact for humans, with some including:

  • Increased cholesterol levels
  • Increased risk of kidney or testicular cancer
  • Increased risk of high blood pressure or pre-eclampsia in pregnant women
  • Small decreases in infant birth weights
  • Changes in liver enzymes
  • Decreased vaccine response in children

What do the findings for Minnesota & Wisconsin include?

The report looked at a variety of EPA data that included samplings of common game fish fillet tissue in inland waterways and on the Great Lakes. While the data from the EPA also includes the presence of other things like mercury and other chemicals, this report specifically looked at PFAs. The report says that 348 of 349 samples from a National Rivers & Streams Assessment showed detectable levels of PFAs, while all 152 samples of Great Lakes fish found PFAs.

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You can see sampling locations in the region in the map below.

An interactive map showing the presence of PFAs in freshwater fish includes samplings that indicate the presence of PFAs in waterways including the St. Louis River, Mississippi River, Rainy River, Minnesota River, St. Croix River, and others in Minnesota; along with Wisconsin River, Red Cedar River, Yellow River, Mississippi River, and others in Wisconsin. Additionally, multiple near-shore sampling locations along Lake Superior were identified.

Contamination in a variety of game fish was found in our region, including northern pike, smallmouth bass, catfish, carp, lake trout, largemouth bass, and others.

While most of Minnesota and Wisconsin's sampling included rivers and streams, the study points to the likelihood of higher concentrations of PFAs in many lakes and ponds, where "these basins don't cycle as frequently".

Of particular concern in the study was the Great Lakes, where PFA concentrations consistently report higher than other freshwater testing locations.


What should anglers do?

The very short answer is to know the risk and follow consumption guidelines.

Every state's Department of Natural Resources offers fish consumption guidance in relation to mercury and other chemicals and contaminants. In most cases, the current recommendation is to limit consumption based on certain factors.

Minnesota's guidance:

The Minnesota DNR's current guidance is broken down into a number of different categories, depending on the person eating the fish, where the fish were caught, and the type/size of fish. They do point out that not every body of water has been sampled for contaminants.

The overall statewide guidance are as follows:

You can see more specific guidance for lakes, fish, and individuals here.

Wisconsin guidance: 

The Wisconsin DNR's current broad, statewide guidance is as follows:

  • Women of childbearing years, nursing mothers, and children under 15:
    • 1 meal per week of bluegill, crappie, yellow perch, sunfish, bullhead, and inland trout
    • 1 meal per month of walleye, pike, bass, catfish, and all other species, except
    • Do not eat musky
  • Women beyond childbearing years, men:
    • Unrestricted bluegill, crappie, yellow perch, sunfish, bullhead, and inland trout
    • 1 meal per week of walleye, pike, bass, catfish, and other species
    • 1 meal per month of musky

Like in Minnesota, this varies from lake to lake. The Wisconsin DNR has a lake finder tool to offer lake-by-lake guidance for fish consumption.

The 10 Commandments Of Ice Fishing In Minnesota & Wisconsin

While these aren't the only rules to abide by (see your local Minnesota or Wisconsin DNR regulations, for example), these 10 guidelines go a long way toward making sure you and other ice anglers have an enjoyable hardwater experience.

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