Study: Mercury can cause NY loon population drop

The report summarizes field research conducted from 1998 to 2007 by the Biodiversity Research Institute, headquartered in Gorham, Maine, and the Wildlife Conservation Society. The work, sponsored by the New York State Energy Research and Development Authority, gathered baseline data to monitor mercury and support environmental regulation.

Mercury contamination in the Adirondacks comes mainly from emissions from coal-fired power plants in the Midwest and elsewhere. In December, the Environmental Protection Agency finalized standards that require coal-fired power plants to update their mercury pollution controls.

Loons are fish-eating, diving aquatic birds about the size of small geese. The study found 75 percent of loons sampled were at a moderate to high risk from mercury in their blood, said Zoe Smith, director of the Wildlife Conservation Society's Adirondack program.

Loons with high mercury levels lack the energy to incubate their eggs properly and take care of their young. As a result, a loon with a high level of mercury produces 40 percent fewer young, the report said.

The researchers studied loons at 44 Adirondack lakes, taking blood and feather samples for mercury testing and observing their nesting behavior. They also tested lake sediment, water, plankton, crayfish and fish to document mercury contamination.

The study showed mercury contamination in the aquatic food chain increased significantly from plankton and crayfish to higher-level predators including loons. Loons in the southwestern Adirondacks were more likely to have elevated mercury levels than those elsewhere in the Adirondack Park.