Mary Jane Koch stands near the site of her family’s former summer cottage on Lake Wisconsin. For decades, the Badger Army Ammunition Plant dumped its waste into the lake, an impoundment of the Wisconsin River. The Army has since removed tons of heavy metals from the lake and has proposed building a public water system to provide clean drinking water to area residents.

Costs, water pollution remain at closed Badger Army Ammunition Plant

Decades of toxic waste disposal at the Badger Army Ammunition Plant — including pouring millions of gallons a day of polluted water into Lake Wisconsin — have contaminated some nearby residents’ drinking water and raised concerns about the long-term effects on their health. But help may be on the way.

Land use is a factor boosting the level of nitrate in the water in Wisconsin. In the Upper Midwest, millions of acres of grassland — which leaches little nitrogen into aquifers — have been converted into fields of corn, soy and other crops since 2008, according to University of Wisconsin-Madison researchers. Here, a farmer harvests corn near Blair in Trempealeau County.

Nitrate in water widespread, current rules no match for it

Levels of nitrate, one of the Wisconsin’s top drinking water contaminants, are increasing. Nitrate comes primarily from fertilizers, including manure, and puts infants and expectant mothers particularly at risk. A projected 94,000 households are drinking private well water with unsafe levels of nitrate. And many of them don’t even know it since few private well owners conduct regular testing.