Published May 03, 2011, 12:00 AM

Big walleye lakes in Minnesota free of chemical repellant

A chemical once found in stain repellants and firefighting foam wasn’t found in high levels in fish from Minnesota’s most popular walleye lakes, according to the Minnesota Department of Health.

By: John Myers, Duluth News Tribune

A chemical once found in stain repellants and firefighting foam wasn’t found in high levels in fish from Minnesota’s most popular walleye lakes, according to the Minnesota Department of Health.

The state on Monday reported that fish taken from nine of the state’s

10 largest walleye lakes had only tiny amounts or no perfluorooctane sulfonate, or PFOS, suggesting those lakes have very little or no contamination from the chemical.

That means the state won’t issue new fish consumption advisories related to PFOS for those lakes — although all the lakes still are listed under various advisories because of mercury contamination in fish, said Pat McCann, fish advisory program manager for the state health department.

The walleye lakes tested for PFOS were Kabetogama, Rainy, Vermilion, Mille Lacs, Lake of the Woods, Leech, Winnibigoshish, Cass and Upper Red Lake. They account for about 40 percent of the statewide walleye harvest and usually are among the most popular lakes with sport anglers. The results mirrored those released in 2010 from 54 other Minnesota lakes outside the Twin Cities.

Minnesota’s walleye fishing opener is May 14.

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

PFOS-related chemicals previously were found in Lake Calhoun in Minneapolis and in Lake Pepin on the Mississippi River, the 10th-largest walleye lake, where fish consumption advisories already have been listed because of PFOS.

PFOS also has been found in fish from Rice Lake and Fish Lake reservoirs near Duluth, and the state has issued an advisory to limit meals of fish from those lakes to once per week for most people, although the lake already had the same restrictions because of mercury contamination. State officials believe those lakes were contaminated from runoff from aircraft firefighting training at the Duluth air base in years past.

Perfluorochemicals are a family of manmade chemicals that have been used for decades to make products that resist heat, oil, stains, grease and water — including nonstick cookware, stain-resistant carpets and fabrics, fire-fighting foam and other industrial applications. Minnesota is one of the few states in the U.S. where these chemicals were manufactured.

The U.S. Environmental Protection Agency? began investigating perfluorinated compounds in 1999 after receiving data that the chemical was showing up worldwide. 3M, which manufactures Scotchguard, announced in 2000 that it had stopped producing PFOS-related chemicals in the U.S.

Studies by 3M show no apparent impact on people. According to the state, high concentrations of PFOS and related compounds cause harmful changes in the liver and other organs in laboratory animal studies. Developmental problems have been seen in the offspring of rats and mice exposed to the chemicals. PFOS in high concentrations over a long period of time also cause cancer in lab animals.

After related chemicals were discovered in fish from metro lakes in 2007 and 2008, state officials began to look for the chemical in fish from rural areas. PFOS is the perfluorochemical that accumulates most in fish.

State officials continue to encourage residents and visitors to eat fish caught in Minnesota lakes because of its many health benefits. But they also caution people to follow the state’s guidelines on limiting meals of fish because of mercury contamination.

Children and pregnant women are most at risk, and some lakes have fish with more mercury than others. Smaller fish have less mercury, which is a potent neurotoxin, and smaller species such as panfish have less contamination.

Minnesota will release an update version of its Fish Consumption Advisory in June with more than 1,300 of the state’s lakes and rivers now tested for mercury levels. For more information, go to