POPs in key species of marine Antarctic ecosystem

Remote areas including the Polar regions were considered to be pristine until contamination was first documented in the 1970's. Given the fact that the xenobiotics detected in polar ecosystems are persistent and toxic, investigating the presence of these chemicals in a pristine environment such as Antarctica has become a priority. In specimens of the most important key species of Antarctic marine food web, Euphausia superba and Pleuragramma antarcticum sampled in the Ross Sea, we evaluated concentrations of the following persistent organic pollutants: polychlorinated biphenyls (PCBs), chlorinated pesticides such as hexachlorobenzene (HCB), and p,p'-DDE. Sampling was carried out in the framework of the Italian National Program for Research in Antarctica (PNRA) from 1999 to 2000. PCB concentrations were higher than HCB and p,p'-DDE by two orders of magnitude; levels of HCB and p,p'-DDE, in the range of 1-5 ng/g wet weight, were low compared to those reported for species in lower latitude marine environments. PCBs values were comparable to those determined in moderately contaminated areas. PCB fingerprints and patterns of isomer classes showed a predominance of low-chlorinated PCBs: tri-, tetra- and penta-CB congeners constituted more than 50% of the total residue in krill and larvae and less than 50% in adult silverfish. The pattern seems common to that of Kanechlor, a technical mixture used mostly in Japan and other Eastern Asian countries that are roughly at the same longitude of the Ross Sea. (C) 2002 Elsevier Science B.V. All rights reserved.