November 6, 2006
WHOI scientists and colleagues at the University of Connecticut have found the first connection between mercury levels in freshwater fish and atmospheric mercury pollution, most of which is derived from fossil fuel combustion. By comparing results from large databases for both mercury concentrations in largemouth bass, a widely distributed freshwater fish species, and atmospheric mercury deposition from monitoring efforts across the contiguous U.S., the researchers found that mercury levels are directly related to the flux of mercury from the atmosphere, which varies five-fold among the states in the analysis. Anthropogenic mercury emissions, mostly from the combustion of fossil fuels, have been estimated to have increased atmospheric mercury levels and deposition about three-fold globally since the Industrial Revolution, suggesting that concentrations of methylmercury in aquatic systems worldwide may have been lower in the pre-industrial past. Future reductions in anthropogenic mercury emissions to the atmosphere could result in proportionally lower levels of methylmercury in aquatic organisms like fish. Results will be published in the November 15 print issue of the journal Environmental Science & Technology and are available now in the online version on the journal.