Mercury in the environment tends to accumulate in certain geographical areas, new research suggests.
In a pair of related studies, David C. Evers of the BioDiversity Research Institute in Gorham, Maine, and his colleagues analyzed mercury concentrations in yellow perch and common loons in the northern United States and southern Canada. Those species provide indicators of ecosystems’ overall exposure to the contaminant, say the researchers.
The team identified five “hot spots” where perch and loon populations showed heavy mercury contamination. These are the Androscoggin and Kennebec rivers in Maine, the Merrimack River that runs through Massachusetts and New Hampshire, the Adirondack Mountains in New York, and central Nova Scotia.
Typically, mercury enters the atmosphere from coal-burning power plants. The researchers determined that an ecosystem’s proximity to such sources had a greater effect on mercury pollution than past studies had indicated.
Air currents, rainfall patterns, and topography also conspire to deliver mercury to the hot spots, Evers and his colleagues report in the January BioScience.