PERSISTENT ORGANOCHLORINE RESIDUES IN DOLPHINS FROM THE BAY OF BENGAL, SOUTH-INDIA

Blubber samples of 12 accidentally netted dolphins from the coastal waters of Porto Novo, southeast coast of India were monitored to assess the persistent organochlorine (HCHs, DDTs, PCBs, and HCB) contamination in these animals. SIGMADDT concentrations ranked first, followed by PCBs, SIGMAHCH, and HCB. HCHs were detected for the first time in dolphins from the tropical waters. The variations in residue levels could be attributed to the physicochemical and biochemical properties of the above compounds. International comparison of residue levels in cetaceans in the recent decade revealed that DDT concentrations in Indian dolphins were comparable to those from other localities whereas PCB levels were low. The continuing contamination by these persistent organochlorines and their toxic effects in tropical cetacean species is predicted in the future.