Mercury chemically defined species

Mercury has been found in seawater in a variety of operationally characterized particulate (> 0.4 or > 0.45 jum) and dissolved ( ionic , colloidal , gaseous , reactive , easily reducible , labile , organically associated , non-reactive ) forms. In addition, chemically defined species have been determined, such as elemental (H, monomethyl- (MMHg) and dimethylmercury (DMHg) Bloom et aL, 1995 Coquery and Cossa, 1995 Iverfeldt, 1988 Leermakers et al, 1995 Mason et aL, 1995). The relationship between the different species of Hg and its total concentration (Hgx) is highly variable in space (with sea area and water depth) and time (daily and seasonal changes). The procedure described here applies to the determination of total mercury . A brief outline, however, is also given on the determination of some of the major species for which more or less standardized methods are in common use. 

To convert the various species of mercury which occur even in strongly acidified seawater Cossa and Courau, 1984) into a well-defined and more easily detectable chemical form, oxidation to labile Hg ions is needed. This is carried out at room temperature with either BrCl Bloom and Crecelius, 1983) or KMn04 (Briigmann et al., 1985). 

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