The content of this website is no longer being updated. For information on current assessment activities, please visit http://www.globalchange.gov/what-we-do/assessment

The Chemical Cycle and Bioaccumulation of Mercury

TitleThe Chemical Cycle and Bioaccumulation of Mercury
Publication TypeJournal Article
Year of Publication1998
AuthorsMorel, F. M. M., A. M. L. Kraepiel, and M. Amyot
JournalAnnual Review of Ecology and Systematics
Volume29
Pagination543-566
Date Published1998
ISBN Number0066-4162
KeywordsANTHROPOGENIC INFLUENCES, biomagnification, DESULFOVIBRIO-DESULFURICANS LS, DISSOLVED GASEOUS MERCURY, DIVALENT MERCURY, ELEMENTAL MERCURY, FOOD-CHAIN STRUCTURE, HUMIC SUBSTANCES, INORGANIC MERCURY, methylation, microbial uptake, NATURAL-WATERS, solubility, speciation, VOLATILE MERCURY
Abstract

Because it is very toxic and accumulates in organisms, particularly in fish, mercury is an important pollutant and one of the most studied. Nonetheless we still have an incomplete understanding of the factors that control the bioconcentration of mercury. Elemental mercury is efficiently transported as a gas around the globe, and even remote areas show evidence of mercury pollution originating from industrial sources such as power plants. Besides elemental mercury, the major forms of mercury in water are ionic mercury (which is bound to chloride, sulfide, or organic acids) and organic mercury, particularly methylmercury. Methylmercury rather than inorganic mercury is bioconcentrated because it is better retained by organisms at various levels in the food chain. The key factor determining the concentration of mercury in the biota is the methylmercury concentration in water, which is controlled by the relative efficiency of the methylation and demethylation processes. Anoxic waters and sediments are an important source of methylmercury, apparently as the result of the methylating activity of sulfate-reducing bacteria. In surface waters, methylmercury may originate from anoxic layers or be formed through poorly known biological or chemical processes. Demethylation is effected both photochemically and biologically.

Reference number

565

Short TitleThe Chemical Cycle and Bioaccumulation of Mercury
Citation Key565