Mercury threat studied
BOISE – Some Nevada gold mines should be monitored for possibly leaking mercury pollution across the border into Idaho, a handful of Idaho environmental officials said.
Gold mines are among the nation’s largest sources of mercury pollution, federal environmental regulators say.
But the mines remain unregulated and officials with the Idaho Department of Environmental Quality say they did not learn about the pollution until last year, when they began writing rules to protect Idaho water from mercury pollution.
Even at low levels, mercury pollution can case neurological damage, especially in young children.
The department officials hope to get air scientists from the Idaho National Engineering and Environmental Laboratory to monitor snow and air for mercury in the Jarbidge Mountains along the state line.
Meanwhile, the environmental advocacy group Idaho Conservation League is threatening to sue the U.S. Environmental Protection Agency if the EPA does not begin to regulate mercury from gold mines. Justin Hayes, the group’s conservation director, said the state Department of Health and Welfare should also study health records across southern Idaho. Health officials have already warned anglers, pregnant women and children not to eat fish from some lakes in the region because of high levels of mercury.
“We need to go into these communities and determine if gold mining in Nevada is poisoning children in Idaho,” Hayes said.
Instead of requiring mines to install the maximum pollution control technologies available – a process that would have taken years to complete and cost millions of dollars – the Environmental Protection Agency opted to offer mining companies a voluntary reduction program, hoping it would bring immediate benefits, said David Jones, associate director for the agency in San Francisco.
Overall, the voluntary program is a huge success, Jones said. The mining companies are expected to exceed the goal of cutting emissions by half this year, down to at least 4,000 pounds, he said.
Gary Goodrich, environmental manager for the Jerritt Canyon mine near Elko, Nev., said until the federal program required miners to report emissions in 1998, he didn’t know the extent of mercury pollution they were sending into the air. That year the mine reported emitting 9,400 pounds – the largest source in the nation.
“I guess it was a testament to the value of the program,” Goodrich said.
Jerritt has cut its mercury emissions to 800 pounds this year, but it remains one of the nation’s largest mercury polluters.
“We’re still trying to work on reducing that 800 pounds,” Goodrich said.
No unusual levels of mercury have been detected in the air by University of Nevada researchers, who began a monitoring program in 2003, but they note that emissions dramatically dropped last year due to the voluntary program with the EPA.
Glenn Miller, a chemistry professor heading the monitoring effort, said their work doesn’t show how much mercury may have been deposited in the decade the mines operated before monitoring began.
“We may never know if that mercury in southern Idaho is from Nevada mining,” Miller said.
Mercury has long been known to be a deadly poison in higher doses, delaying walking and talking and reducing learning ability in children, according to EPA reports. Agency officials say there is growing evidence that mercury exposure can damage the heart and increase blood pressure in adults.
Methylmercury is the organic form that is the most toxic. In rivers and lakes, it moves up the food chain to concentrate at high levels in the flesh of fish.
But most of the mercury emitted from the mines is the less-toxic elemental mercury. However, elemental mercury can mix in the atmosphere with other chemicals and oxidation can transform it into methylmercury once it is deposited on land.
“The question is how quickly does it oxidize?” said Don Essig, water quality standards manager for the Idaho Department of Environmental Quality. “That’s what we need to know to determine if these sources are affecting Idaho.”