By Graham Scher – R & J Broadcasting | August 9, 2025

North Woods, MINN. – Hundreds of lakes across the North Woods are contaminated with mercury, including those in protected areas like the Boundary Waters. That contamination is worsening now despite years of efforts to close coal-fired power plants and scrub industrial emissions.

Minnesota has reduced the amount of mercury it spews into the atmosphere by nearly two-thirds since 2005. Yet the level of mercury found in walleye and northern pike in many of the state’s lakes has continued to slowly but steadily rise for the past 30 years. 

In the Boundary Waters, more than 100 lakes are considered impaired because of mercury levels that lead to limits on fish consumption.

Anglers are warned against eating more than one fish per month, while children and pregnant women are warned to not eat any.