STUDIES OF GLOBAL BASE-LINE POLLUTION .17. LEVELS OF POLYCHLORINATED-BIPHENYLS IN THE LOWER TROPOSPHERE OF THE NORTH-ATLANTIC AND SOUTH-ATLANTIC OCEAN

Fourteen polychlorinated biphenyl (PCB) congeners were quantified in air samples of the tropospheric boundary layer of the Atlantic Ocean. The samples were taken on the German research vessel ''Polarstern'' during north-south cruises across the Atlantic Ocean (1990, 1991), and on the Capo Verde islands in the North Atlantic Ocean (1992). Values for the sum of PCB were between 48 pg/m(3) (values for the seven indicator congeners were [in pg/m(3)]: PCB 28: 1.3; PCB 52: 5.0; PCB 101: 3.0; PCB 118: less than or equal to 0.5; PCB 138: 1; PCB 153: 1; PCB 180: <0.2) in the Westwind Belt of the eastern North Atlantic and 22 pg/m(3) (values for the seven indicator congeners were [in pg/m(3)]: PCB 28: 2.3; PCB 52: 3.4; PCB 101: less than or equal to 0.5; PCB 118: <0.2; PCB 138: <0.2; PCB 153: <0.2; PCB 180: <0.2) in the Westwind Belt of the central South Atlantic. Up to 385 pg/m(3) (values for the seven indicator congeners were [in pg/m(3)]: PCB 28: 2.6; PCB 52: 11.7; PCB 101:28.4; PCB 118: 9; PCB 138: 21; PCB 153: 18; PCB 180: 5.5) were measured of the coast of South Patagonia. A difference depending on latitude and on terrestrial influenced air masses between the lower and the higher chlorinated congeners was observed. The levels of three- and tetrachlorinated congeners were highest in the Trade Wind regions. The contents of the higher chlorinated congeners had maxima in samples influenced by continental air masses. A correlation of the levels of the lower chlorinated congeners in air over the South Atlantic with the surface water temperature and thus with the temperature dependent gas/water partition coefficient K-gw was observed.