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1J - Bioaccumulation (WEP/67) The role of nutrients, organic carbon, and sulfur species on mercury methylation and bioaccumulation. Bigham, Gary1, Mackay, Chris1, 1 Exponent, Bellevue, Washington, USA ABSTRACT- The concentrations of nutrients, organic carbon, and sulfur species in surface and pore waters are among the many water quality variables that have been proposed to influence the rate of mercury methylation and the efficiency of methylmercury bioaccumulation. Some previous studies have evaluated the relationships between water quality variables and bioaccumulation of mercury in fishes while other studies have examined the influence of organic carbon and sulfur species on methylation in sediment. We examine the regulation of mercury methylation in sediment by mercury sulfide species and the interaction with organic carbon. We also examine the influence of nutrients on bioaccumulation. Data from previous investigations in North America are used, with special attention to data from the Florida Everglades. We find that, of the many variables that can influence the rate of mercury methylation, sulfide and organic carbon can be significant variables. Phosphorus can have a significant influence on bioaccumulation through biodilution. In areas of the Everglades where total phosphorus in water exceeds about 16 ug/L, the biomass of primary producers is sufficient to dilute adsorbed methylmercury resulting in a lower concentration of mercury adsorbed to phytoplankton/periphyton and higher levels of the food web. Key words: Methylation, Bioaccumulation, Methylmercury, Mercury |
