Mercury in Aquatic Ecosystems

Mercury occurs naturally in the environment and cycles among the atmosphere, water, and sediments. Human activities such as coal burning power plants and waste incineration increase the amount of mercury cycling in the environment. Since the industrial revolution, anthropogenic mercury emissions have increased atmospheric mercury levels about threefold, causing corresponding increases in mercury levels in terrestrial and aquatic ecosystems.

Mercury that is released into the atmosphere can be transported long distances and deposited in aquatic ecosystems, where it is methylated to methylmercury. Mercury is a neurotoxicant, to which the human fetus is very sensitive. Methylmercury is an organic form of mercury, the most toxic form, and the form that bioaccumulates in fish. Wildlife and humans are exposed primarily through consumption of contaminated fish. The factors that make some aquatic ecosystems susceptible to this bioaccumulation, however, are unknown, making protection of human health and the health of fish-eating wildlife a challenge.

Research focuses on the processes of mercury methylation and accumulation in aquatic ecosystems, factors that determine ecosystem susceptibility, and investigation of whether reduced emissions will reduce mercury accumulation in susceptible ecosystems.

• National and Regional Assessments of Mercury Occurrence and Cycling in the Environment
• Mercury Experiment to Assess Atmospheric Loading in Canada and the United States (METAALICUS)
• Mercury Cycling in Aquatic Ecosystems

Aquatic ecosystems across the Nation are being studied to identify the factors that control where and when mercury accumulates to toxic levels in the food chain

Program Headlines Related to Mercury Research

• Some Ecosystems will Respond to Reductions in Mercury Emissions
• Mercury from Yellowstone's Geysers
• A New Source of Methylmercury Entering the Pacific Ocean
• Fish in Some Streams Accumulate Mercury
• Mercury Found to Migrate Horizontally from Landfill
• USGS Contributes to the Design of a Proposed National Mercury Monitoring Network (MercNet)
• A New Source of Methylmercury Entering the Pacific Ocean
• Mercury Concentrations in Streams Found to Go Through Daily Cycles
• USGS Mobile Atmospheric Mercury Laboratory Makes an Impact
• National Fish Mercury Model Available On-Line
• OSTP Report on Methylmercury in the Gulf of Mexico
• Glacial Ice Cores Reveal the History of Global Mercury Contamination
• Mercury-Contaminated Fish--Is it Old or New Mercury?

Fact Sheets

• Are Walleye from Lake Roosevelt Contaminated with Mercury?: USGS Fact Sheet FS-102-97
• Glacial Ice Cores Reveal a Record of Natural and Anthropogenic Atmospheric Mercury Deposition for the Last 270 Years: USGS Fact Sheet FS-051-02
• Mercury Contamination of Aquatic Ecosystems: USGS Fact Sheet FS-216-95
• Mercury Contamination from Historic Gold Mining in California: USGS Fact Sheet FS-061-00

More information on Mercury Research

• Mercury Research in the USGS, Provides information on mercury research across a wide spectrum of U.S. Geological Survey science programs
• USEPA Mercury Page
• Fish Consumption Advisories (USEPA)

New Publications

Upcoming Publications

• Litterfall mercury dry deposition in the Eastern USA: Risch, M.R., DeWild, J.F., Krabbenhoft, D.P., Kolka, R.K., and Zhang, L., Environmental Pollution, doi:10.1016/j.envpol.2011.06.005 (IN PRESS).
• Methylation of Hg downstream from the Bonanza Hg mine, Oregon: Gray, J., Hines, M.H., Krabbenhoft, D.P., and Thoms, B., Applied Geochemistry, p. 9 (IN PRESS).
• Mercury export from the Yukon River Basin and potential response to a changing climate: Schuster, P., Striegl, R., Aiken, G., Krabbenhoft, D., DeWild, J., Butler, K., Kamark, B., and Dornblaser, M., Environmental Science and Technology (IN PRESS).
• Mercury distribution and lipid oxidation in fish muscle--Effects of washing and isoelectric protein precipitation: Yuansheng, G., Krabbenhoft, D.P., Liping, R., Egelandsdal, B., and Richards, M.P., Journal of Agricultural and Food Chemistry (IN PRESS).

Newly Published

• Formation of nanocolloidal metacinnabar in mercury-DOM-sulfide systems: Gerbig, C.A., Kim, C.S., Stegemeier, J.P., Ryan, J.N., and Aiken, G.R., 2011, Environmental Science and Technology, doi:10.1021/es201837h (Advanced Web release).
• Spatial and seasonal variability of dissolved methylmercury in two stream basins in the eastern United States: Bradley, P.M., Burns, D.A., Murray, K.R., Brigham, M.E., Button, D.T., Chasar, L.C., Marvin-DiPasquale, M., Lowery, M.A., and Journey, C.A., 2011, Environmental Science and Technology, v. 45, no. 6, p. 2048-2055, doi:10.1021/es103923j.
• Source identification of Florida Bay's methylmercury problem--Mainland runoff versus atmospheric deposition and in situ production: Rumbold, D., Evans, D., Niemczyk, S., Fink, L., Laine, K., Howard, N., Krabbenhoft, D., and Zucker, M., 2011, Estuaries and Coasts, v. 34, no. 3, p. 494-513, doi:10.1007/s12237-010-9290-5.
• Diurnal trends in methylmercury concentration in a wetland adjacent to Great Salt Lake, Utah, USA: Naftz, D.L., Cederberg, J.R., Krabbenhoft, D.P., Beisner, K.R., Whitehead, J., and Gardberg, J., 2011, Chemical Geology, v. 283, no. 1-2, p. 78-86, doi:10.1016/j.chemgeo.2011.02.005.