Mercury 'Hot Spots' Identified in U.S. and Canada
Saturday, January 6, 2007
Two newly published scientific reports suggest that mercury contamination has created at least five "hot spots" in New England and Canada, places where the neurotoxin has accumulated in fish and wildlife to such an extent that it could harm human health and local ecosystems.
The 11 scientists, who work at institutions including Syracuse University and Vermont's Department of Environmental Conservation, analyzed how mercury has accumulated in two indicator species in the northern United States and southern Canada. In both cases, they were able to identify several regions where mercury in yellow perch and common loons was above acceptable levels.
David C. Evans, who heads a Maine-based nonprofit group called the BioDiversity Research Institute and is one of the papers' lead authors, said the study shows that some areas of the country are more susceptible to mercury pollution than others.
"You need to look at the fish and wildlife to understand what areas are problematic," Evans said. "A coal-burning plant in a wetland area would have far greater impact on human health and wildlife than a coal-burning plant in a dry, grassy area."
Taken together, the two papers, published in this month's edition of the peer-reviewed journal BioScience, represent the most comprehensive ecological analysis of mercury accumulation ever conducted in the United States. They are significant because the Environmental Protection Agency has created a system requiring electric utilities to cut their mercury emissions 70 percent by 2025 but allowing power plants to trade pollution credits in reaching that target.
Under the Clean Air Mercury Rule, power plants in some regions may emit more mercury than others, which has prompted some to question whether the new system will result in mercury hot spots across the country.
One EPA official, who spoke on the condition that he not to be identified because of agency rules, said the two papers raise questions about the system, which will begin to take effect in 2010. In the 2005 federal notice announcing the rule, the agency wrote that it would "evaluate and take appropriate action" if more information emerged about mercury hot spots.
"There's a growing body of evidence that there are places where mercury deposition is a serious problem," the official said. "This is something that needs to be looked at very carefully before putting in a cap-and-trade system."
But EPA spokeswoman Jessica Emond said the agency remains committed to the rule.
"U.S. mercury air emissions have dropped by 45 percent since 1990," Emond said. "Under the Bush administration, the U.S. is the first nation in the world to regulate mercury emissions from coal-fired power plants."
Scott Segal, a lobbyist who represents electric utilities, noted that when the nation adopted a cap-and-trade system for sulfur dioxide, the largest polluters cleaned up fastest.
"Nothing in the report establishes a basis for changing course away from trading systems for mercury control like the one found in the Clean Air Mercury Rule," Segal said. "A well-designed cap-and-trade program remains the most appropriate response to dealing with mercury emissions from power plants."
But the researchers said their findings suggest that local and regional emissions can have a serious impact on local wildlife and human health. They identified five regions as "biological mercury hot spots," including New York's Adirondack Mountains, the Merrimack River in Massachusetts and New Hampshire, Maine's Androscoggin and Kennebec rivers, and central Nova Scotia.