Mercury ‘hot spot’ identified in Maine

Researchers have documented high mercury levels in wildlife in several Western Maine lakes and reported evidence of three more potential mercury “hot spots” elsewhere in the state, according to two studies released Tuesday.

A team of 11 scientists, including several from Gorham-based BioDiversity Research Institute, studied mercury levels over three years in thousands of wildlife tissue samples from New England, New York and Eastern Canada.

The results showed that while the neurotoxin was present throughout the region, five areas jumped out as “biological hotspots” with mercury contamination levels above healthy levels. While not the sole source, coal-fired power plants were blamed as the largest contributor of airborne mercury.

The upper watersheds of the Androscoggin and the Kennebec rivers – including such popular recreation spots as Moosehead and Flagstaff lakes – were grouped together in the reports as the only hot spot in Maine. High levels of mercury were found in loons and yellow perch in those waterways.

Researchers also identified nine “areas of concern” in the region – including three in Maine – where they found preliminary evidence of higher mercury levels in wildlife. The three Maine locations identified in the two reports, both published in the peer-reviewed journal BioScience, are in the lower Penobscot River, Down East and in the St. John River.

David Evers, executive director of the BioDiversity Research Institute, stressed that the studies do not mean that everyone should stop eating fish from those watersheds. Moosehead Lake, for example, is so large that loons in one area contained unsafe levels while loons on other parts of the lake were comparatively healthy.

Evers did not provide details, however, about exactly where the mercury levels were highest and the maps contained in the report are too broad to pinpoint specific areas.

But Evers said people should be aware of the health risks of eating too much fish from the identified regions and adjust their diets accordingly. Pregnant women and young children, who are most susceptible to mercury-related health problems, should potentially avoid eating any fish from the hot spot areas, he said.

“I’d be extremely careful,” Evers said.

The study group, which was organized by the Hubbard Brook Research Foundation in Hanover, N.H., argued that emissions from U.S. coal-fired power plants accounted for most of the contamination they studied. When emissions from regional coal-fired plants declined, so did mercury levels in wildlife, the reports said.

In Maine, fluctuating water levels in reservoirs also helped mercury leach out into the environment.

Mercury is dangerous because it accumulates in tissue and becomes more concentrated as it moves up through the food chain. In addition to perch and loons, the researchers studied a smaller number of samples from bald eagles, smallmouth bass, brook trout, otters and mink.

The four other hot spots identified by the reports were in New York’s Adirondack Mountains, the upper Connecticut River in Vermont and New Hampshire, the Merrimack River in Massachusetts and southern New Hampshire and in central Nova Scotia.

Samples taken from wildlife in the nine areas of concern also tested positive for high levels of mercury; however, not enough samples were taken to label the areas hotspots, Evers said.

The authors of the reports said the findings cast serious doubts on federal models for mercury contamination. In the one specific case examined in depth in the study, the authors found that mercury deposition was five times higher than Environmental Protection Agency estimates near a coal-fired plant in southern New Hampshire.

The researchers said the reports underscored the need for more monitoring of wildlife, especially fish species liable to end up on someone’s dinner plate.

They also said the findings support calls for the EPA to go beyond its current goal of a 70 percent reduction in mercury emissions by 2025. Several states, including Maine, are suing the EPA to force the agency to adopt more stringent rules.

Evers praised Maine’s mercury-reduction efforts and called on the state to continue pushing the issue nationally.

“By cleaning up our backyard we can point a finger elsewhere and push other states to clean up their backyards as well,” he said.

U.S. Sen. Susan Collins praised the reports and criticized the federal EPA’s mercury emissions rules. Collins, a Maine Republican, plans to submit legislation mandating lower emissions standards and creating a nationwide monitoring network.

“I have long argued that EPA used faulty science in order to justify an insufficient mercury rule, and these studies prove it,” Collins said in a statement. “EPA misrepresented the mercury problem based on computer data which had not been peer-reviewed, and then put out a rule which does not account for mercury hotspots and which places children and pregnant women at risk.”

EPA officials said the agency is working on a system of nationwide monitoring sites and that current rules will reduce mercury deposition in the northeastern U.S. by 80 percent.

“Under the Bush administration, the U.S. is the first nation in the world to regulate mercury emissions from coal-fired power plants,” Jessica Emond, the EPA’s deputy press secretary, said in a statement.

Copies of the reports and maps are available online at: www.briloon.org