engleski

Relationship between mercury species and solid sulfides in aquatic sediments

Distributions of total and methylmercury in sediment and porewater, as well as speciation of reduced sulfur species were investigated in different kinds of aquatic sediments (freshwater, estuarine and marine), characterized with a large range of mercury contamination level. Total mercury was found to be better correlated with CRS (chrome reducible sulfur), than with AVS (acid volatile sulfides). Methylmercury, both in sediments and porewater, was related to AVS and AVS/CRS ratio, as maximums of these species were obtained at the same sediment depths in the investigated sediment cores. Relationships obtained between mercury species (total and methylmercury) and reduced sulfur species in investigated sediments suggest that mercury in sediment is related to solid sulfides in several ways. Concentration of mercury species in the solid phase can be regulated by adsorption onto inorganic and organic reduced sulfurs in sediments. It is also possible that redox conditions and sulfur concentration/speciation where AVS are stabilized favorite methylation over demethylation process resulting in maximums of theses species at the same sediment depths.

mercury; methylmercury; sediment; solid sulfides

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