These are developed to help you plan what fish to keep as well as how often and how much sport fish to eat. In Wisconsin, copies of the Health Guide are available at any DNR office. PCBs, were once used in such products as electrical transformers, cutting oils and carbonless paper and hydraulic fluid. Although banned in 1976, PCBs do not decompose easily and, therefore, remain in the environment. PCBs accumulate in sediments at the bottom of the river.
Fish can absorb the PCBs from the water, suspended sediments or food.
The good news is that the levels of PCBs in the Mississippi River are slowly decreasing because the PCBs already in the sediment are being buried as the river deposits new clean sediment. PCBs are a health concern because they are suspected to be cancer causing, and research has shown they impair reproduction in some animals. PCB's have also been linked to developmental and growth problems in children born to women who regularly ate Great Lakes fish. The amount of PCBs in a fish taken out of the Mississippi River is dependent upon many factors. The kind of fish, its size, age, fat content, diet and location all can influence the amount of PCBs.