Increasing Levels and Biomagnification of Persistent Organic Pollutants (POPs) in Antarctic Biota

This dataset reports a study carried out on the Weddell seal (Leptonychotes weddellii), and southern elephant seal (Mirounga leonine), feeding at higher levels in the food web on fish and cephalopods, and reports that they biomagnified most compounds by up to 2 orders of magnitude relative to krill. In these top predators p,p'-DDE attained the highest concentrations with 0.2 μg g-1 EOM (extractable organic matter). However, hexachlorobenzene (HCB) was the predominant pollutant in all other animals studied. It is noteworthy that HCB levels in Weddell seals and 60 in southern elephant seals were considerably lower than in their dominant prey, the pelagic fishes Pleuragramma antarcticum and Gymnoscopelus nicholsi and the squid Psychroteuthis glacialis . The same result was found for ringed seals (Phoca hispida), and harbour seals (Phoca vitulina), in the northern hemisphere. Since the physical and chemical properties of HCB leave no doubt that pinnipeds absorb this compound from their food, an exceptional capacity to eliminate HCB by biotransformation must be postulated in these mammals. Top predators are generally thought to represent indicators of biomagnified POPs. However, the selective elimination of hexachlorobenzene in pinnipeds demonstrates that biomonitoring should not be confined to single taxa.
The example of extremely low HCB levels in seals and experimental evidence on PCB patterns being related to PCB elimination in marine animals of different systematic position showed that changes in POP composition between various species of the same community are also controlled by elimination capacities. Hence, a cluster analysis classifying the investigated species on the basis of their POP concentrations revealed groups of similar ecological and systematic status. Pelagic fish (Trematomus eulepidotus, G. nicholsi, P. antarcticum, C. gunnari) and squid (P. glacialis) were in the same set as their prey, Antarctic krill, whereas Adelie penguins and the seals were separated in two further groups.