Less sulfate, less methylmercury, safer fish harvests

St. Louis River estuary

March 8, 2023:  There’s another benefit to sulfate remediation in freshwater ecosystems: less sulfate also bodes well for healthier fish and wildlife. That’s because in these settings, sulfate boosts the conversion of mercury to methylmercury, the substance that makes fish unsafe to eat and has neurotoxic effects on birds and animals. One example is the St. Louis River, which flows into Lake Superior. Taconite processing in northern Minnesota produces both sulfate and mercury, which find their way to the river by air and by watershed drainage. Especially in these river estuaries, methylization is a big problem. Read Stephanie Hemphill’s Agate article “Trying (again) to tackle mercury in the St. Louis River” online or as a PDF.  Photo source: USGS