Studies of hexachlorocyclohexane-isomers (HCHs) and selected triazine herbicides in solution and suspension were carried out in the Pomeranian Bight in 1995. The concentrations of HCHs and triazines were determined by gas-liquid chromatography (GC) or by GC in connection with quadrupole mass spectrometry(GC/MS). Particulate and dissolved material were separated by means of an in-situ filtration/extraction system. The seasonal variability and regional distribution of the various components were investigated in January, April, July and September 1995. Their distribution in the western Pomeranian Bight is described. The concentrations of individual hexachlorocyclohexane-isomers were in the range of 100–1 000 pg l–1 in solution and 20 to 60 pg l–1 in suspension. The levels of the triazines in solution showed pronounced differences between the individual components (atrazine (2–20 ng l–1), simazine (5–30 ng l–1), terbuthylazine (< 5 ng l–1)), but they were one order of magnitude higher compared with the hexachlorocyclohexane-isomers. The concentration of triazines in suspension was low, often below the limit of detection (25 pg l–1).