What contaminants are found in Minnesota fish?
In Minnesota, mercury is the contaminant in fish that causes the most concern. Air pollution is the major source of mercury that contaminates the fish in Minnesota’s lakes and rivers—see Sources of Mercury Pollution and the Methylmercury Contamination of Fish in Minnesota (PDF: 29KB/2 pages). About 70 percent of the mercury in the air is the result of emissions from coal combustion, mining, incineration of mercury-containing products and other human sources. Over time, fish can accumulate relatively high mercury concentrations. That’s why it’s important to make wise choices about the fish you eat and how often you eat it. Fish in Lake Superior and major rivers such as the Mississippi River may contain PCBs. These synthetic oils had many uses and are found in electrical transformers, cutting oils, and carbonless paper. Although they were banned in 1976, they do not easily break down and remain in the water and lake sediments for years. PCB levels in Minnesota waters are slowly decreasin
