For more than 75 years, mercury contamination from Badger Army Ammunition Plant has poisoned fish and aquatic life in Lake Wisconsin, placing public health at risk. Safe removal of contaminated sediments is desperately needed to protect human health from ongoing exposures.
Current mercury levels
Despite two previous dredge actions, approximately 16 acres of Gruber’s Grove Bay of Lake Wisconsin still contains mercury-impacted sediment. Mercury concentrations in certain areas of the bay are as high as 6.3 milligrams per kilogram (mg/kg), far above the cleanup goal of only 0.36 mg/kg established by Wisconsin DNR.
Consumption of fish
The primary public health concern associated with mercury in the bay is contamination of fish tissue, according to the Wisconsin DNR. Mercury accumulates in fish tissue as methylmercury. This form of mercury presents the greatest risk to human health through consumption of contaminated fish.
Testing by the U.S. Army has confirmed that mercury levels in game fish caught in Gruber’s Grove Bay are higher than found in fish in the rest of the Wisconsin Riverway.
Infants in the womb can be exposed to methylmercury when their mothers eat fish and shellfish that contain methylmercury. This exposure can adversely affect unborn infants’ growing brains and nervous systems. These systems may be more vulnerable to methylmercury than the brains and nervous systems of adults are.
History of Wastewater Discharge to Gruber’s Grove Bay
During active production years, Badger Army Ammunition Plant discharged wastewater to Gruber’s Grove Bay of Lake Wisconsin resulting in the contamination of lake bottom sediments. Sediment contaminants include lead, copper, arsenic, ammonia, nitroglycerine, PCBs and methylmercury – the most toxic form of mercury. Mercury is a highly toxic element and there is no known safe level of exposure. Ideally, neither children nor adults should have any mercury in their bodies.
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