Bioaccumulation patterns of polychlorinated biphenyls and chlorinated pesticides in Northwest Atlantic pilot whales

Abstract Contaminant exposure is widespread among marine mammals but is of unknown significance. This study characterized organochlorine bioaccumulation in pilot whales, and these bioaccumulation patterns are proposed as representative of Northwest (NW) Atlantic cetacea. Samples were collected from whales stranded in Massachusetts and caught in nets. Polychlorinated biphenyl (PCB) and chlorinated pesticide concentrations were determined via GC/ECD and found to be similar to those reported for other NW Atlantic odontocetes. The organochlorine in highest concentration was 4,4′-DDE, followed by trans-nonachlor, 4,4′-DDD, dieldrin, cis-chlordane, Cl4(52), Cl5(95), Cl5(101), Cl5(118), Cl6(138), Cl6(149), Cl6(153), Cl7(180), and Cl7(187). The concentration of 19 pesticides was higher in blubber (21 ± 26 μg/g lipid “ppm”) than liver (5.0 ± 7.1 ppm). The concentration of 26 PCB congeners was also greater in blubber (7.6 ±7.1 ppm) than liver (0.4 ± 7.3 ppm). Principal component analysis and ANOVA indicated that blubber accumulated proportionately more of the most recalcitrant compounds, such as 4,4′-DDE and nonmetabolizable PCBs, compared to liver. Whales that stranded together had more similar bioaccumulation than animals of the same gender or maturity. The high variation among individuals in tissue concentrations and the similarity within a stranding group suggest that pilot whale pods are exposed to a large range of pollutant sources, such as through different prey and feeding locations.