CONCENTRATIONS OF SYNTHETIC ORGANICS IN THE ATMOSPHERE OF THE NORTH AND SOUTH PACIFIC OCEAN.

As part of a program to study the geochemical cycles and air-sea exchange of natural and anthropogenic chemicals, samples of air and rain were taken at remote island sites in the North and South Pacific Oceans. The compounds chosen for analysis included hexachlorobenzene (HCB), hexachlorocyclohexanes (HCH), polychlorobiphenyls (PCBs), DDT and related compounds, dieldrin, and chlordane. Concentrations of organics were very consistent between the sites in the Southern Hemisphere. Comparison of data on selected chlorinated organics in the atmosphere shows that concentrations are from 2 to 10 times lower in the Southern Hemisphere. Furthermore, compounds with long atmospheric residence time (such as HCB) have less of an interhemispheric gradient compared to shorter-lived compounds (such as HCH).