DIETARY UPTAKE EFFICIENCY OF HCBP IN CHANNEL CATFISH - THE EFFECT OF FISH CONTAMINANT BODY BURDEN

Groups of juvenile channel catfish (Ictalurus punctatus) were exposed for 10 days to control or contaminated sediment, spiked with C-14-hexa chlorobiphenyl (HCBP, 130 mu g . kg(-1) dry weight), in order to estab lish a known body burden. At the completion of that exposure, subsampl es of fish were taken for HCBP analysis and the remaining fish were tr ansferred to clean media. Each group transferred to clean media was th en divided into two subgroups and offered either control or contaminat ed diet for 4 weeks. The contaminated diet (Tubifex worms) was spiked with C-14-HCBP (16.6 mu g . kg(-1) wet weight). Feeding rates of rubif ex were quantified as were fish growth rates and lipid levels. Fish (f ive specimens) were collected at the beginning of the dietary exposure and after 10, 20, and 30 days of exposure. Average individual growth rate constants were similar in all fish groups and ranged from 0.005 d (-1) to 0.007 d(-1). Both fish groups fed contaminated Tubifex accumul ated HCBP in an apparent linear fashion over the study period. The bio accumulation factors (BAFs) were 1.38 and 1.66 for accumulation from s ediment and uptake from food, respectively. The dietary uptake efficie ncy for HCBP was found not to be affected by contaminant present in th e fish body.