Investigations on individual chlorobiphenyls (PCBs) were carried out in the pelagial of the western Pomeranian Bay. An in-situ filtration/extraction system was used to distinguish between the particulate and dissolved chlorobiphenyls. Multidimensional gas chromatography (MDGC) techniques were applied to the separation and identification of individual chloro-biphenyls. The regional distribution of dissolved and particle (SPM) associated individual chloro-biphenyls is presented. The investigations of chlorobiphenyls in different seasons indicate no pronounced seasonal variability in the aqueous phase. However, the concentrations of particu-late chlorobiphenyls did exhibit seasonal maxima depending on plankton productivity.