Health officials find unsafe mercury levels at 5 more lakes

Health officials find unsafe mercury levels at 5 more lakes

By Todd Hartman, Rocky Mountain News

January 25, 2007

State health regulators have discovered unsafe mercury levels in fish in five more Colorado water bodies, including popular Horsetooth Reservoir west of Fort Collins, prompting new warnings for anglers.

The new data show mercury accumulations in four species of fish at levels greater than one-half part per million, the level at which regulators say people should limit their consumption. Pregnant women and children should heed even tighter limits or avoid the fish altogether, officials say.

The latest mercury warnings are in addition to advisories already posted at nine other Colorado lakes and reservoirs, the bulk of them in the state's southwestern quadrant near a cluster of large coal-fired power plants in the Four Corners region that many believe are a key contributor to the problem.

The five new sites are Horsetooth, Totten Reservoir near Cortez, Purdy Reservoir near Grand Junction, Horseshoe Reservoir west of Walsenburg and Trinidad Lake near Trinidad. Fish species affected are walleye, saugeye, wiper and largemouth bass.

A key source of the mercury is most likely airborne deposits of emissions from coal-burning power plants. But determining from which plants - or which states or nations - the pollution originates is controversial, as industry, environmentalists and scientists often disagree on the matter.

"We certainly have coal-fired plants in this state and some in adjoining states - there are a whole lot of coal-fired plants across the whole Northern Hemisphere," said Steve Gunderson, director of Colorado's Water Quality Control Division. "There are questions about contributions North America is receiving from Asia and China."

The new mercury warnings come amid contentious debate in Colorado and nationally over proposals requiring power plants to control mercury emissions. A state air-quality board was to rule on the matter Wednesday, but interest groups asked for more time to reach a consensus.

"I think this is a wake-up call to Colorado that the problem of mercury from coal-fired power plants is real, and we have to find a solution quickly," said Will Coyne of Environment Colorado. "This is a serious problem, with serious ramifications that will require serious solutions."

Once deposited in water, natural processes can transform mercury into a highly toxic form known as methylmercury, which accumulates in fish and animals, including humans, that eat fish. Exposure is of greatest concern for unborn babies and young children, where it may harm the developing nervous system, affecting a child's ability to think and learn.

The news could force the Colorado Division of Wildlife to alter the way it manages some fisheries. At Horsetooth Reservoir, for example, mercury warnings will discourage people from taking the largest fish, as they'd likely have the highest levels.

"We need to adjust our management of that reservoir so it doesn't become top-heavy with big, top-predator fish," said Tyler Baskfield, a DOW spokesman.

Jim Sanderson, an attorney representing utilities, said he doesn't believe the elevated mercury levels are linked to Colorado facilities, but he added: "That doesn't mean nothing should be done. The utilities I'm working with are willing to make reductions over time, as the program calls for."

hartmant@RockyMountainNews.com or 303-954-5048