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
Burning coal for energy production contributes large amounts of mercury to the atmosphere. Photo Credit: Phillip J. Redman, USGS.
Program Science Feature Articles on Mercury Research
More information on Mercury Research
- Environmental origins of methylmercury accumulated in subarctic estuarine fish indicated by mercury stable isotopes: Li, M., Schartup, A.T., Valberg, A.P., Ewald, J.D., Krabbenhoft, D.P., Yin, R., Balcom, P.H., and Sunderland, E.M., 2016, Environmental Science and Technology, v. 50, no. 21, p. 11559-11568, doi:10.1021/acs.est.6b03206.
- Effects of mercury and thallium concentrations on high precision determination of mercury isotopic composition by Neptune plus multiple collector inductively coupled plasma mass spectrometry: Yin, R., Krabbenhoft, D.P., Bergquist, B.A., Zheng, W., Lepak, R.F., and Hurley, J.P., 2016, Journal of Analytical Atomic Spectrometry, v. 31, p. 2060-2068, doi:10.1039/C6JA00107F (Advanced Web release).
- Microbial mercury methylation in antarctic sea ice: Gionfriddo, C.M., Tate, M.T., Wick, R.R., Schultz, M.B., Zemla, A., Thelen, M.P., Schofield, R., Krabbenhoft, D.P., Holt, K.E., and Moreau, J.W., 2016, Nature Microbiology, v. 1, p. 16127, doi:10.1038/nmicrobiol.2016.127 (Supplementary Information).