News Coverage
Park has big fish to fry: mercury in trout
Published April 7, 2004
ESTES PARK - Unexpectedly high levels of mercury have been found in trout pulled from high-altitude lakes in Rocky Mountain National Park, researchers said Wednesday.
The most severely contaminated trout contained only half the amount of mercury that the Environmental Protection Agency considers hazardous for human consumption.
Even so, the finding was a bit of a surprise, said Donald H. Campbell, a research hydrologist with the U.S. Geological Survey in Denver.
"They're not really high levels, but perhaps higher than one would have expected at high-mountain Colorado lakes," Campbell said.
"The park is more pristine than a lot of places, but it's not totally unaffected by the activities of society," he said at the Rocky Mountain National Park Research Conference.
If mercury levels continue to rise, warning signs about fish consumption may someday have to be posted in the park, Campbell said.
Coal-fired power plants are the largest man-made source of airborne mercury, emitting about 48 tons per year in the United States. A toxin that accumulates in the food chain, mercury poses particular health risks for young children and the unborn.
But the mercury emitted by power plants has never been regulated.
That is supposed to change under Clean Air Act limits to begin in 2008. During the past two years, environmentalists and the power industry have sparred over just how tough those regulations should be.
At Rocky Mountain National Park, airborne mercury falls to the ground in rain and snow. Likely sources include power plants in the West, but pollutants crossing the Pacific Ocean from Asia may also contribute.
Colorado's mercury-deposition problem was first revealed in the 1990s at the Buffalo Pass monitoring site near Steamboat Springs, directly east of large coal-fired power plants in Craig and Hayden.
The mercury levels at Buffalo Pass were startlingly high, comparable to amounts seen in the Upper Midwest and the Northeast.
But the levels recorded in Rocky Mountain National Park during the past three years are "equal to, or more than, Buffalo Pass," Campbell said Wednesday.
Cutthroat and brook trout from eight lakes above 9,000 feet were tested for mercury.
The highest level seen in park trout was 0.15 parts per million. The EPA's guide for safe fish consumption is 0.3 ppm or less of mercury.