POLYCHLORINATED-BIPHENYLS IN NORTH-SEA WATER

Thirty-one individual chlorobiphenyl congeners (CBs) were analysed in water from the North Sea. Single column gas chromatographic and multidimensional gas chromatographic techniques were used to separate the constituents of the complex mixtures. Characteristic concentrations of individual CBs in off-shore water were between < 0.05 and 2 pg dm-3, and up to 40 pg dm-3 in near-coastal waters. SIGMA-CB values in off-shore waters were two to three times higher than values measured in the open Atlantic. Most concentrations in suspended matter were below the limit of detection (0.05 pg dm-3 in 100 dm3 samples). The most toxic (non-ortho-Cl substituted) CBs and their ortho-chlorine substituted derivatives were also determined. The sum of their concentrations was two to four times smaller than that of the non- or less toxic CBs. High concentrations and different compositions of the CB mixtures were found in the region where oil platforms are located. The much lower concentration levels reported here compared with older data reflect the improved measures to avoid contamination during sampling and laboratory procedures, as well as the analysis of a large volume of sea water (at least 100 dm3 for off-shore waters).