Contamination par les organochlorés des dauphins de Commerson des îles Kerguelen

Top predators like marine mammals have been intensively used for monitoring the contamination of the marine environment, particularly in industrialized coastal areas of the Northern Atlantic Ocean. Such data concerning contamination in the Southern hemisphere are very scarce. Samples were taken in the fatty protuberance of the forehead (melon) from eleven Commerson's dolphins (Cephalorhynchus commersonii, Lacépède, 1804) caught in the coastal waters of the Kerguelen Islands (Southern Indian Ocean). They were analyzed for DDT, PCB and HCB, using capillary gaz chromatography. The levels of contamination [DDT= 1 150 ± 650, PCB = 1 150 ± 770, HCB=500±300ng/g of extracted matter (lipids)] are between ten and a hundred times Jess than those found in similar species from polluted areas of the Northern hemisphere. In this material, the contamination pattern is characterized by the enhancement of the most persistent components in the PCB group, the presence of high levet of HCB and the occurrence of unidentified compounds.