Lake’s falling oxygen levels concerning

Oxygen levels are declining in Lake Coeur d’Alene, raising concerns about the heavy metals buried in the mud at the bottom of the lake. The lake is a repository for 75 million tons of sediment polluted with lead and other heavy metals that washed downstream from more than a century of mining activity in Idaho’s Silver Valley. For 25 years, scientists have monitored the lake’s water chemistry, charting trends in oxygen levels that act as a cap on the metals. “Deep down here at the bottom of the lake, the oxygen levels are decreasing. The changes we’re seeing are subtle and slow, but they are real,” said Craig Cooper, a lake scientist for the Idaho Department of Environmental Quality/ Becky Kramer , SR. More here.