DISTRIBUTION OF PERSISTENT ORGANOCHLORINES IN THE OCEANIC AIR AND SURFACE SEAWATER AND THE ROLE OF OCEAN ON THEIR GLOBAL TRANSPORT AND FATE

Concentrations of organochlorines such as hexachlorocyclohexanes (HCHs), DDTs, chlordanes, and PCBs were determined in the air and surface water from various oceans in 1989-1990, for understanding their recent distribution and the role of ocean in the long-range atmospheric transport and fate on global terms. The atmospheric concentrations were found to be still higher in the Northern Hemisphere than in the Southern Hemisphere, although the distribution pattern suggested the shift or expansion of their major sources from the mid to low latitudes during the last decade. In surface water, HCHs showed a considerable contamination over 40-degrees-N, whereas DDTs were higher near tropical Asia. Chlordanes and PCBs exhibited rather uniform distributions in both the hemispheres. Estimations of fluxes by gas exchange across the air-water interface gave insight into the dispersal of organochlorines through oceanic atmosphere depending on their Henry's law constants and the tendency of more transportable ones to deposit into the cold waters as an ultimate sink.