Chlorinated hydrocarbons in the Southern Ocean

• Main Authors: Shinsuke Tanabe, Ryo Tatsukawa
• Format: Report
• Language: English
• Published: Department of Environment Conservation, Ehime University 1983
• Subjects: Antarctic; Antarctic Ocean; Indian; Pacific; Southern Ocean; The Antarctic; Antarc*; Memoirs of National Institute of Polar Research; Polar Research
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=1434; http://id.nii.ac.jp/1291/00001434/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=1434&item_no=1&attribute_id=18&file_no=1

PCBs and chlorinated hydrocarbon pesticides such as DDT and HCH (BHC) were measured in air and water samples taken from the Antarctic, western Pacific and eastern Indian Oceans. Chlorinated hydrocarbons are widely distributed in the open ocean environment over the northern and southern hemispheres. The most striking fact was their presence in the Antarctic Ocean. ΣDDT (sum of p, p'-DDE, p, p'-DDT and o, p'-DDT) and ΣHCH (sum of α, β and γ isomers) concentrations in air and surface water were found to be relatively high in the mid-latitudes of the northern hemisphere. In addition, fairly high concentrations of ΣDDT were observed in the tropical regions and in the mid-latitudes of the southern hemisphere, but ΣDDT levels between the two hemispheres were not much different. HCH isomer compositions found in the northern hemisphere were in the order of α-HCH>γ-HCH>β-HCH, while in the southern hemisphere γ-HCH was apparently dominant. DDT compound compositions were rather uniform in all locations surveyed, where p, p'-DDT occupied more than 50%. These results indicate that the environmental pollution by these persistent chemicals spread all over the earth, and that the world situation regarding PCB and pesticide use and the atmospheric circulation seem to account for their global distribution. Chlorinated hydrocarbons were also found in the subsurface water as deep as several thousand meters. The vertical profiles of PCBs and ΣDDT were rather uniform, while ΣHCH concentrations decreased systematically with depth. These profiles seem to be associated with the sinking particles in the water column. A rapid downward transport of chlorinated hydrocarbons is expected in the Antarctic Ocean where primary productivity is very high.