Levels of some high molecular chlorinated hydrocarbons in sediment samples from the eastern Adriatic coastal waters

It is well documented that synthetic chlorinated hydrocarbon residues are widespread through the oceanic ecosystem. The Adriatic Sea, as semi-enclosed body of water, is of special interest for an evaluation of the entry, extent and fate of the pollution by chlorinated hydrocarbons. Sediments samples were collected from 1976 to 1990 at seven areas and over forty stations located on the eastern Yugoslav coastal waters. Concentrations of chlorinated insecticides and polychlorinated biphenyls in surface sediment samples ranged from <0.1 to 93.9 for DDTs and from <0.5 to 294 μg kg^?1 for PCBs on dry weight basis. It is very important to stress that all these samples were analyzed from a single analytical group (mostly by the same analyst), using a uniform methodology. Total DDT and PCB concentration do not exhibit Gausian distribution in the investigated area and collecting period, so it is necessary to be very careful in interpreting the concentration data using parametric statistics. Very often, the pollutant levels in sediment samples differ significantly in samples collected at the same time at nearby stations.