Accumulation and distribution of polychlorinated dibenzo-p-dioxin, dibenzofuran, and polychlorinated biphenyl congeners in atlantic salmon (Salmo salar)



Adult Atlantic salmon (Salmo salar) were fed on four diets containing polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) for 30 weeks. Lipid-normalized concentrations showed that all congeners were equally partitioned between whole-fish and fillet samples. Skinned fillet accumulated approximately 30% of the total PCDD/F and PCB content in fish. Accumulation efficiencies in whole fish were 43% for 2,3,7,8-chlorinated dibenzo-p-dioxins and dibenzofurans, 83% for dioxin-like PCBs, and 78% for other PCB congeners. Among PCDD/Fs, tetra- and pentachlorinated congeners were preferentially accumulated in salmon, whereas hepta- and octachlorinated dibenzo-p-dioxins were excreted in the feces. Substitution patterns that were associated with a preferential accumulation of PCBs in salmon included non-ortho substitution and tetrachlorination. Accumulation efficiencies and lipid-normalized biomagnification factors (BMFs) were not influenced by the PCDD/F and PCB concentrations of the diets. Biomagnification (BMF > 1) of tetra- and pentachlorinated dibenzo-p-dioxins and dibenzofurans and of all the PCBs was observed. Differences in the behavior of PCDD/F and PCB congeners resulted in a selective enrichment of the most toxic congeners in salmon.