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News Release
March 24, 2026

Contact information

New fish consumption guidelines aim to limit exposure to mercury and PFAS

Analysis of fish tissue, previously outsourced to Canada, now takes place at Minnesota’s own Public Health Lab

After analyzing data showing the presence of mercury and per- and polyfluoroalkyl substances (PFAS) in the tissue of some fish from certain Minnesota waterbodies, the Minnesota Department of Health (MDH) has updated its fish consumption guidelines.

The updates include new length-based guidelines for walleye and northern pike, more protective guidelines for Northeast Minnesota, and new guidelines for the Vermillion River in Dakota and Scott counties.

“Generally speaking, fish are a good part of a healthy diet,” said Angela Preimesberger, MDH’s fish consumption guidance program lead. “Fish can be a source of important omega-3 fatty acids, which help with heart health and brain function. However, based on our analyses, we advise limiting how many servings of certain fish you eat from certain locations.”

Mercury remains a concern, particularly in Northeast Minnesota

For the first time since 2020, scientists in the Fish Consumption Guidance program undertook a comprehensive review of all available mercury data going back to 1967, using new analysis methods. Their findings led them to develop:

• Specific Northeast Fish Consumption Guidelines for Cook, Lake and St. Louis counties. Fish from waterbodies in Northeast Minnesota generally have higher mercury concentrations than fish from waterbodies in other regions of the state. More information, including a map showing estimated mercury concentrations by region, can be found on the MDH webpage, Updated Mercury Analyses for Fish Consumption Guidelines. The updated guidelines are based not on a significant increase in the amount of mercury in these areas, but on the need to be more protective of sensitive groups and improve the clarity of the guidelines by reducing the need for many waterbody-specific guidelines.
• Length-based guidelines for sensitive populations in the Waterbody-specific, Northeast, and Statewide Fish Consumption Guidelines for walleye and northern pike. These guidelines apply statewide, because larger fish tend to have higher mercury concentrations. Adding fish-lengths allows for more fish consumption by recommending people eat smaller fish. Certain industrial processes emit mercury into the air, which then settles in water and accumulates in fish. If people regularly eat fish with elevated mercury, the mercury can damage their kidneys, liver and nervous system. It also can impact understanding and learning in young children.

Additional information about mercury and health can be found on MDH’s website: Contaminants and Minnesota Fish.

PFAS found in fish from the Vermillion River

For the past few years, MDH has issued fish consumption guidelines related to PFAS in fish from the Mississippi River and other Minnesota waterbodies. This year, MDH added the Vermillion River from headwater streams in Scott and Dakota counties, including the South Branch of the river, to the Hastings Dam. See Fish Consumption Guidance Updates for Minnesota Waterbodies.

PFAS are human-made chemicals that do not break down over time and have been widely used for decades to make products that resist heat, oil, stains, grease and water. PFAS may accumulate in a person’s body over time and may become a health concern. They are linked to developmental effects, including low birth weight in infants and a weaker immune system in children. Exposure to some PFAS may also cause changes in liver function and increase cancer risks.

Eating fish is just one way that people are exposed to PFAS. For example, PFAS are present in many of the products found in people’s homes, including nonstick cookware, stain-repellant carpet and waterproof clothing. Minnesota has been taking action to eliminate PFAS for many years, and current recommendations can be found in the state’s PFAS Blueprint.

How MDH develops its fish consumption guidelines

Fish consumption guidelines are based on three factors:

• Who you are. Fish consumption guidelines differ for sensitive groups (children under age 15 years and people age 15 and older who are or could become pregnant, those who are breastfeeding or plan to breastfeed) and general populations (everyone else).
• The species and length of the fish. The maximum number of servings recommended per week or month may vary among fish species caught in the same waterbody. Longer fish tend to have higher mercury levels, so MDH has included length-based guidelines for sensitive groups.
• Where you caught the fish. Some waterbodies have lower levels of contaminants than others. To find out what the guidelines are for a waterbody where you plan to fish, check the DNR’s LakeFinder (for lakes) or MDH’s Waterbody-specific, Northeast, and Statewide Fish Consumption Guidelines webpage (for rivers and creeks). MDH’s Fish Consumption Guidance Program works with other programs at the Minnesota Department of Natural Resources (DNR) and the Minnesota Pollution Control Agency (MPCA) through the Fish Contaminant Monitoring Program to select lakes and rivers to monitor for contaminants.

Since 1974, MDH has used data from these monitoring activities to advise anglers on fish consumption when levels of mercury or polychlorinated biphenyls (PCBs) are elevated to keep exposure low for people eating Minnesota fish. The Fish Contaminant Monitoring Program added PFAS in 2004.

In 2024, MDH received funding through the Clean Water Fund to build internal capacity through state-of-the-art lab equipment and expert personnel to analyze the tissue of fish for contaminants. PFAS testing capacity is very low across the U.S., so Minnesota previously had to outsource its testing to a lab in Canada. Approximately 500 samples of Minnesota fish tissue are now analyzed in MDH’s Public Health Lab each year.

“Analyzing fish tissue for contaminants is just one of the many ways we conduct surveillance to protect public health,” said Sara Vetter, director of MDH’s Public Health Lab. “Having local testing capacity is more cost-effective and provides us with the flexibility to test for other emerging contaminants in Minnesota waters as they are identified and become important to track.”

-MDH-

For more information, contact:
Amy Barrett
MDH Communications
651-201-4993
Amy.Barrett@state.mn.us

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