METAALCIUS: A Whole Ecosystem Experiment to Study the Environmental Fate of Mercury
- 907 Downloads
Atmospheric mercury depositions have increased approximately by a factor of three since industrialization, which also led to increase of methylmercury (MeHg) levels in fish, spawning a large number of health advisories. Mercury is now the most common contaminant responsible for fish consumption advisories in the United States and Canada. Almost all US states have regulations against fish consumption due to high mercury levels. Unacceptable fish mercury concentrations exist in all Canadian provinces, including remote “pristine” lakes. Because of the many human and environmental health risks associated with mercury exposure via fish consumption, implementation of effective Hg emission control regulations is discussed in many nations. However, such measures are expected to be very costly and at the same time, safe emission levels are difficult to establish because the available science is still not able to answer if and to which degree reductions in atmospheric mercury deposition translate into changes in fish mercury concentrations. This relationship cannot be understood by examining historical or regional data, mainly because of confounding effects of other environmental factors. Laboratory experiments provide good control over test conditions, but fail to simulate the complex links in the real world that connect atmospheric mercury deposition and fish mercury. To overcome this conundrum two unique experimental approaches were combined in the Mercury Experiment To Assess Atmospheric Loading In Canada and the United Sates (METAALICUS). This experiment is carried out at he whole ecosystem scale by loading an entire lake and its watershed with isotopically labeled mercury providing full-scale realism plus the control necessary to examine the effects of one critical factor: mercury loading. The overriding question METAALICUS set out to answer is: What happens to fish mercury concentrations when there is a change in atmospheric mercury deposition?
KeywordsSphagnum Moss Peat Core Mercury Isotope Environmental Health Risk Experimental Lake Area
Past and present funding for METAALICUS includes support from the Canadian Department of Fisheries and Oceans, the National Sciences Engineering and Research Council of Canada, Environment Canada, the Canadian Forest Service, the Electric Power Research Institute, the US Environmental Protection Agency, the US Geological Service, the Wisconsin Department of Natural Resources, and the U.S. Department of Energy.
- Harris, R.C., J.W.M. Rudd, M. Amyot, C. Babiarz, K. Beaty, P. Blanchfield, R.A. Bodaly, B. Branfireun, C.C. Gilmour, J. Graydon, A. Heyes, H. Hintelmann, J. Hurley, C.A. Kelly, D. Krabbenhoft, S. Lindberg, R. Mason, M. Paterson, C. Podemski, A. Robinson, K. Sandilands, G. Southworth, V. St. Louis, and M. Tate, 2007: Whole-ecosystem study shows rapid fish-mercury response to changes in mercury deposition. Proc. Nat. Acad. Sci. 104, 16586–16591CrossRefGoogle Scholar
- Hintelmann, H., and N. Ogrinc, 2003: Determination of stable mercury isotopes by ICP/MS and their application in environmental studies, in: Biogeochemistry of environmentally important trace elements, Y. Cai and C.O. Braids, Editors. ACS Symposium Series Vol. 835, Washington, DC. pp. 321–338Google Scholar
- Hintelmann, H., R.D. Evans, and J.Y. Villeneuve, 1995: Measurement of mercury methylation in sediments by using enriched stable mercury isotopes combined with methylmercury determination by gas chromatography – inductively coupled plasma mass spectrometry. J. Anal. Atom. Spectrom. 9, 619–624CrossRefGoogle Scholar
- Hintelmann, H., R. Harris, A. Heyes, J.P. Hurley, C.A. Kelly, D.P. Krabbenhoft, S. Lindberg, J.W.M. Rudd, K.J. Scott, and V.L. St.Louis, 2002: Reactivity and mobility of new and old mercury deposited in a Boreal forest ecosystem, during the first year of the METAALICUS study. Environ. Sci. Technol. 36, 5034–5040CrossRefGoogle Scholar
- Paterson, M.J., P. Blanchfield, C. Podemski, H. Hintelmann, R. Harris, N. Ogrinc, J.M.W. Rudd, and K.A. Sandilands, 2006: Bioaccumulation of newly-deposited mercury by fish and invertebrates: An enclosure study using stable mercury isotopes. Can. J. Fish Aquat. Sci. 63, 2213–2224CrossRefGoogle Scholar