News release: State's largest walleye lakes test ‘clean' for PFCs in fish

News Release
May 2, 2011
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State's largest walleye lakes test 'clean' for PFCs in fish

New mercury data will be included in updated fish consumption guidelines in June

Fish taken in 2010 from nine of Minnesota's 10 largest walleye lakes had levels of perfluorooctane sulfonate (PFOS) that were either very low or undetectable, suggesting those lakes have very little or no contamination from perfluorochemicals (PFCs). That is one of the early findings from new data for fish contamination recently received by the Minnesota Department of Health (MDH) from the Minnesota Department of Natural Resources (DNR) and the Minnesota Pollution Control Agency (MPCA).

The results of the PFC testing mean that advice on how much fish can be eaten safely from those walleye lakes will not be impacted by perfluorochemicals. That's good news for Minnesotans who like to catch and eat fish from those waters, said Pat McCann, MDH fish advisory program manager.

"Minnesotans can continue to enjoy the benefits that come from eating fish from some of their favorite lakes without concern for PFCs," McCann said. "People should continue to follow the existing consumption advice for those lakes, which is based on mercury."

The walleye lakes tested were Kabetogama, Rainy, Vermilion, Mille Lacs, Lake of the Woods, Leech, Winnibigoshish, Cass and Upper Red Lake. The 10th largest walleye lake is Lake Pepin, part of the Mississippi River, which had been previously tested and had levels of PFCs that led to recommendations to limit consumption for some species. Perfluorochemicals are a family of man-made chemicals that have been used for decades to make products that resist heat, oil, stains, grease and water.

Minnesota's 10 largest walleye lakes are the most important fishing waters in the state, according to the DNR. They account for about 40 percent of the statewide walleye harvest and are usually among the most popular lakes with sport anglers.

After PFCs were discovered in fish from Lake Calhoun in the metro area in 2007, state officials began to look for PFCs in fish from other waters of the state. PFOS is the perfluorochemical that accumulates most in fish.
Under the 2010 round of testing, state scientists retested some of the waters, or connected waters, that had higher levels of PFCs in fish from previous testing. The levels found were similar to previous measurements. New waters tested for PFCs included several rivers in Greater Minnesota and some additional metro area lakes. Results from the testing indicate no need for advice to limit consumption in any new areas based on PFCs. Those waters may have existing advice to limit consumption based on mercury or PCBs.

The 2010 collections of PFC data will be included, along with new data on mercury and PCBs from 2009 and 2010 collections, when MDH updates its fish consumption guidelines in June. The DNR collects fish for testing by the Minnesota Department of Agriculture. MDH then analyzes the test data and establishes the consumption advisories. The guidelines provide consumers and anglers with information to help them make choices about the fish they eat.

"Most people can benefit from including more fish in their diet," said McCann. "Fish are a great source of low fat protein. Eating fish contributes to brain and eye development in the growing fetus. The omega-3 fatty acids found in fish may promote heart health for adults. We strongly encourage Minnesota residents to follow the advice in the guidelines and eat fish that are low in contaminants."

For more background on perfluorochemicals in Minnesota, go to

The updated advice will include data on mercury in fish from over 250 lakes and about 50 rivers. About 50 of these waters have never been tested and will bring the total number of waters tested in the state to nearly 1,300. Funding from the Legacy Amendment and its precursor over the last five years has allowed an increase in the number of waters with fish tested for mercury.

MDH will announce when the site-specific advice is updated through its Twitter and Facebook accounts and its fish advisory email notification list. To subscribe, go to: and click on the envelope icon in the right sidebar. The statewide advice remains the same. Statewide safe eating guidelines are available online at

The fish consumption advice can also be accessed through a new Department of Natural Resources application for Android smartphones at


For more information, contact:

Doug Schultz
MDH Communications

Pat McCann
Environmental Health