High mercury levels found in Idaho reservoir Nevada gold mines located downwind of Salmon Falls Creek could be source Researchers have detected levels of mercury in a southern Idaho reservoir 150 times higher than found in lakes in the northeast United States.
Salmon Falls Creek Reservoir south of Twin Falls lies downwind from four Nevada gold mines that emit into the air more mercury annually than 25 average coal-fired power plants. Until 2002, the mines released more than triple the mercury.
Idaho environmental regulators say they don't have conclusive proof the gold mines caused the mercury pollution in the popular fishing reservoir. But they haven't found other possible sources of mercury, which could cause neurological damage, especially in young children, even at low levels.
An Idaho National Laboratory scientist found this summer that mercury levels in the air rose 30 to 70 percent higher than normal levels when winds blew from the southwest, where the mines are located. This is the first time anyone has monitored the air or the reservoir for mercury.
"The mines are the only sources big enough to cause those peaks," said Michael Abbott, an INL atmospheric scientist.
Since 2002, Idaho Department of Health and Welfare officials have warned anglers at Salmon Falls Creek Reservoir to limit how much fish they eat after discovering the fish had high levels of mercury.