Catskills contaminated with mercury
New research has identified as many as 14 biological mercury "hotspots" in northeastern North America and suggests that contamination in wildlife is linked to pollution from coal-fired industry.
The hotspots are areas where wildlife has excessive levels of contamination. One known hotspot occurs in the Adirondack Mountains, and another is suspected in the Catskills.
In humans, mercury can damage brain development, learning and neurological functioning, especially on developing fetuses and children. The effects documented in wildlife are similar.
The two studies were coordinated by the Hubbard Brook Research Foundation and are featured in the January issue of the peer-reviewed scientific journal BioScience.
The 11-scientist Hubbard Brook team used more than 7,300 observations to quantify mercury levels in fish, birds and other wildlife at lakes and reservoirs from New York to Nova Scotia. The results go a long way toward confirming earlier results that used computer models to predict the location of hotspots.
Mercury, a naturally occurring element, is released into the atmosphere when power plants or other industrial facilities burn coal. The largest sources of mercury in New York are Hudson Valley cement plants.
Fish are a main source of exposure
After mercury rains down and is converted into a toxic form, people and wildlife are exposed primarily from eating contaminated fish. Last year, New York expanded advisories warning the public against eating many species of wild fish throughout the entire Catskill and Adirondack re-gions — the most pristine wilderness areas of the state. Forty-three other states also warn residents against eating fish from certain waters.
"We were surprised to find that the Adirondack Mountains of New York had some of the highest mercury levels in fish and loons in the northeastern United States," said Charles Driscoll, a lead author of one of the studies, and a professor of environmental systems engineering at Syracuse University.
The average mercury levels in yellow perch were more than twice the Environmental Protection Agency's human health criterion. Blood mercury levels in 25 percent of central Adirondack loons, which eat fish, exceeded wildlife health thresholds. Catskill fish and songbirds also had excessive levels of mercury, but too few sites have been sampled to confirm the region as a "hotspot."
The scientists found that decades of acid rain have made the Adirondacks and Catskills sensitive to mercury pollution.
"The Adirondack and Catskills are getting a double-whammy from emission sources such as coal-fired power plants," Driscoll said.
The studies also found mercury deposition is five times higher at a New Hampshire hotspot near a coal plant, indicating the Environmental Protection Agency's "cap-and-trade" mercury regulation may fail to reduce the harm from some plants.
The Environmental Protection Agency's strategy for curtailing mercury pollution is to restrict the total amount of mercury emitted by all plants, but allow heavier polluters the option of purchasing credits from plants that reduce their emissions. This strategy will reduce the overall load of mercury entering the environment, but would allow for continued or increased emissions at specific plants.
"Our modeling results support a growing body of evidence that a significant fraction of the mercury emitted from coal-fired power plants in the U.S. is deposited in the area surrounding the plants," said Thomas Holsen, professor of civil and environmental engineering at Clarkson University and a co-author of the studies.
Many states — including New York — have adopted rules rejecting the federal plan to allow the trading of mercury emissions, and call for steeper and faster reductions.
Those laws should result in a cleaner environment. The scientists found that mercury levels in fish and wildlife can decline relatively quickly when emissions decline — a new finding for the Northeast.
"There is still a lot that we don't understand about mercury, but it is clear that biological mercury hotspots occur and that mercury emissions from sources in the U.S., as opposed to China and other countries overseas, are the leading cause," Driscoll said. "Mercury emissions will have to be reduced substantially from current levels if we are to see recovery in sensitive watersheds in the Northeast."