ABSTRACT
Mercury is one of the most toxic elements impacting on human and ecosystem health and therefore is one of the most intensively studied environmental pollutants. Mercury exists in a large number of physical and chemical forms with a large variety of properties that affect its complex distribution, biogeochemical transformation and toxicity. Table 10.1 lists common mercury species in environmental and biological samples. All mercury species are toxic, and organic mercury compounds generally are more toxic than inorganic species. In addition, the toxic effects of methylmercury (MeHg) can be signifi cant due to its tendency to bioaccumulate or biomagnify within the aquatic food chain. Moreover, inorganic Hg2+ can undergo biomethylation, resulting in the formation of MeHg and dimethylmercury (DMeHg). These reactions are reversible
1State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China, 430074. aEmail: zhuzl03@gmail.com; zlzhu@cug.edu.cn 2Faculty of Earth Sciences, China University of Geosciences, Wuhan, China, 430074. *Corresponding author
with demethylation facilitated by microorganisms and/or photolytic decomposition. Figure 10.1 illustrates the potential biotic and abiotic reactions, transformations, exchanges within and among reservoirs, and biological uptake of the primary Hg species in marine systems (Fitzgerald et al. 2007).
