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>  News Releases >   2007 >   January

New studies link mercury pollution hotspots to U.S. coal-fired power plants and other sources

Dartmouth College Office of Public Affairs • Press Release
Posted 01/09/07 • Sue Knapp
• (603) 646-3661

Celia Chen
Celia Chen (Photo by Joseph Mehling '69)

A Dartmouth researcher is part of the team that has identified five known and nine suspected biological mercury hotspots in northeastern North America, and the researchers suggest that coal-fired power plants in the U.S. are major contributors. The team reports their findings in two studies published in the January issue of the journal BioScience.

The studies are the result of a three-year effort by the Hubbard Brook Research Foundation (HBRF), and Celia Chen, a research associate professor in Dartmouth's biological sciences department, was part of the 11-person team.

In the two studies, the authors say that U.S. coal-fired power plants are the major source of the problem and document new ways that airborne mercury emissions can cause biological hotspots — namely in watersheds sensitized by decades of acid rain and reservoirs manipulated for power production. The HBRF team of scientists used an extensive database of more than 7,300 samples to quantify mercury levels in fish, loons, and other wildlife from New York to Nova Scotia.

The team linked the biological mercury hotspots to sources of mercury pollution and found that mercury emissions to the air are the leading cause. The studies state that one of the biological mercury hotspots with the highest mercury levels in fish occurs downwind of a major coal-fired power plant in southern New Hampshire. Another biological mercury hotspot exists in the Upper Connecticut River area of New Hampshire and Vermont.

"These findings should be important to both environmental managers and legislators with regard to protecting human health and managing mercury emissions," says Chen. "One paper presents indicators of mercury sensitivity, which should be useful to lake managers in identifying lakes with higher mercury concentrations in fish, and the other paper defines mercury hotspots as locations on the landscape in the northeast U.S. and southeast Canada. Together these findings have important implications for the current mercury cap-and-trade programs which would allow large local sources to continue unabated resulting in the persistence of mercury hotspots."

The studies also present a new analysis showing that mercury deposition is five times higher than previously estimated by the Environmental Protection Agency (EPA) near a coal plant in the vicinity of a biological mercury hotspot spanning southern New Hampshire and northeastern Massachusetts — calling into question EPA methods and the appropriateness of the cap-and-trade policy in the EPA Clean Air Mercury Rule.

The HBRF team also determined that mercury levels in fish and wildlife can decline relatively quickly in response to decreased airborne mercury emissions within the region — a new finding for the Northeast.

Other authors on the paper include: Charles T. Driscoll, Syracuse University, Syracuse, N.Y.; Young-Ji Han, who was a postdoctoral research fellow with the Hubbard Brook Research Foundation, Hanover, N.H.; David C. Evers, BioDiversity Research Institute, Gorham, Maine; Kathleen Fallon Lambert, Hubbard Brook Research Foundation; Thomas M.Holsen, Clarkson University, Potsdam, N.Y.; Neil C. Kamman, Vermont Department of Environmental Conservation, Water Quality Division, Waterbury, Vt.; Ronald K. Munson, Tetra Tech, Inc., Mars, Penn., M. Wing Goodale, BioDiversity Research Institute; Thomas A. Clair, Environment Canada, Sackville, New Brunswick, Canada; and Thomas Butler, Institute of Ecosystem Studies and Cornell University, Ithaca, N.Y.

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