Mercury is a neurotoxin and can be harmful to human health. We know that mercury can accumulate in fish, especially game fish, which people can eat and expose themselves to mercury. However, only a certain kind of mercury, called methylmercury, will accumulate in fish. We know this kind of mercury is produced in the environment by bacteria, but still don't know why some places have more methylmercury in them than others. One example of this is the St. Louis River Estuary in Duluth, Minnesota. We know the fish that eat in the Estuary have more mercury in them than fish that eat upstream or downstream, and are trying to find out why. Check out video below or this article from the Duluth News Tribune for more information!