Persistent organic pollutants in key-species of a Ross Sea pelagic trophic web

Adélie penguin (Pygoscelis adeliae) stomach contents,krill (Euphausia superba andE. crystallorophias) and silverfish (Pleuragramma antarcticum) from the Ross Sea were analysed todetermine several persistent organic pollutants (POPs). In discussing the data, the prey-predator linkagebetween these species was taken into account. Sampling was carried out during the 1995/96 and 1999/00Italian Antarctic Expeditions. Fifty four polychlorobiphenyls (PCBs) and p,p’-DDE and hexachlorobenzene(HCB) were quantified in stomach contents of penguins nesting at Edmonson Point (Victoria Land) and inwhole specimens of silverfish and krill from the Ross Sea. Xenobiotic concentrations in organisms were lowcompared to data reported for many marine species of lower latitudes and ranged from 0.22 ng g-1 wet wtp,p’-DDE in krill to 161 ng g-1 wet wt PCBs in silverfish. Fingerprints and class of isomer patterns showed apredominance of low chlorinated PCBs, mainly in pelagic organisms. Average input of these POPs throughthe diet was also evaluated. Concentrations of the most toxic non-ortho PCBs, IUPAC nos 77 (3,3',4,4'), 126(3,3',4,4',5) and 169 (3,3',4,4',5,5'), were 1.63 pg g-1, 7.31 pg g-1 and 0.23 pg g-1 wet wt, respectively, instomach content samples. Stomach contents had 0.037 pg g-1 wet wt TEQ (Toxic Equivalents) of whichpenta-CB126 accounted for most of the toxicity