Mercury pollution is widespread in Minnesota lakes and poses a threat to our public health. Small amounts of mercury can have a destructive effect on our neurological and nervous systems and are especially detrimental to young children and pregnant women.

Exposure to mercury most often happens when people eat fish contaminated with the element. The major sources of mercury pollution in our lakes include coal-fired utilities, taconite processing, and the unintentional release of mercury used in products.  Examples of the last are municipal trash incineration, fluorescent light bulb breakage, scrapped cars, and thermometers and other gauges. Mercury released into the air or ground makes its way into lakes, where it can be converted to methyl mercury, the form that is readily taken up by fish. The methyl mercury accumulates in fish tissue, and is most concentrated in top predator fish like walleye and northern pike.

Surprisingly, mercury pollution is most severe in northeast Minnesota, where the lakes are otherwise fairly pristine. This is because many of these lakes and wetlands are higher in sulfate reducing bacteria that are largely responsible for transforming elemental mercury into methyl mercury. But it is a serious problem across the entire state. In fact, the Department of Health has warned Minnesotans about eating fish from every lake in the state.

To address this problem, the Minnesota Pollution Control Agency conducted a statewide TMDL (water quality restoration plan) for mercury and developed a plan to implement the reductions prescribed by the TMDL. MCEA was a key stakeholder in that process.

Minnesota’s mercury diet plan calls for a reduction in aggregate statewide mercury emissions of 93 percent from 1990 levels.  This translates to a goal of 789 pounds per year of mercury released in Minnesota.  A key provision in the implementation plan was a requirement that new or expanded sources of mercury be offset by additional controls beyond those needed to achieve the 789-pound goal.  These offsets are to be contained in air and water discharge permits issued by the Minnesota Pollution Control Agency. 

Unfortunately, the MPCA has propsed to issue a permit to US Steel's Keetac facility and Minntact facility. The Keetac permit will allow an additional 75 pounds of mercury emissions without requiring offsets or a compliance deadling. MCEA submitted comments and testified at the MPCA Citizens' Board hearing on the Keetac permit, objecting to the increased emissions. US EPA later weighed in and required the MPCA to make many of the changes requested by MCEA.