Bioaccumulation and assimilation efficiency of hexachlorobiphenyl (HCBP) in yellow perch as a function of both fish and diet lipid level

Evaluation of factors which control the uptake and bioaccumulation of lipophilic contaminants by fish and terrestrial animals is critical to the implementation of bioenergetics-based food web models used to ecological risk assessment. Among these factors some of the most important are feeding and egestion rates, lipid content of both an animal and its diet as well as chemical and food assimilation efficiencies. In this study, groups of juvenile yellow perch were fed lab-formulated low and high-lipid diet for a period of 3 months in order to establish a significant difference in body total lipid content. After that period fish were divided into subgroups and offered either low or high-lipid diet spiked with {sup 14}C-HCBP. Fish were fed contaminated diet for 1 month followed by 1 month of elimination period. Feeding rates during both periods were quantified. Fish (5 specimens) were collected at the beginning of the dietary exposure and every 10 days thereafter and analyzed for {sup 14}C-HCBP and lipid content. Bioaccumulation and assimilation efficiency related to the lipid level in fish and in the diets as well as to contaminant concentration in the diet will be discussed.