TEMPORAL AND SPATIAL TRENDS OF HISTORIC MERCURY ACCUMULATION IN THE NEW YORK FINGER LAKES

Previous investigation of sediment cores from the North American Great Lakes and inland lakes in the Great Lakes airshed revealed that local and regional atmospheric emissions have been the dominant sources of mercury (Hg) to those lakes over the last 150 years. In this study, the history of Hg inputs to six New York Finger Lakes, located within the Great Lakes watershed, was reconstructed using ²¹⁰Pb-dated sediment to determine the contributions of local coal-fired power plants. We selected this region for study because two Finger Lakes have at least one coal-fired power plant on their shore: Seneca Lake and Cayuga Lake.

By the 1900s, Hg accumulation increased sharply in lakes proximal to coal-fired power plants. Changes in Hg accumulation in the other lakes is not as pronounced. Hg profiles in all six lakes mimic the history of coal combustion for residential and commercial heating in New York, Pennsylvania, Ohio, and the U.S. as a whole. The similarity in pattern emphasizes that these lakes are receiving their Hg flux from similar atmospheric sources. Hg profiles in Seneca Lake and Cayuga Lake illustrate the most dramatic changes since ~1890, perhaps due to local or watershed level factors such as proximity to the coal-fired power plant, watershed size, land use, and percentage of wetland that control export of Hg from the watershed to the lake.