Detecting and characterising sources of persistent organic pollutants (PAHs and PCBs) in surface sediments of an industrialized area (harbour of Trieste, northern Adriatic Sea)

A sediment sampling based on a two-dimensional mapping was performed in the harbour of Trieste (northern Adriatic Sea), considering 28 sites exposed t o pollutant inputs from harbour and industrial activities. Polycyclic aroma tic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) were determine d in surface sediments, because these very persistent pollutants seem to be responsible for the depletion of benthic populations observed in this area . The correlation matrix indicates that PAHs and PCBs are non-correlated, a nd probably have different sources. Both cluster analysis performed on the sampling sites and graphical drawing of the PAH sediment contents make it p ossible to locate along the shoreline a band of more polluted sediments, cl ustered around a site facing a steelmaking factory, to be considered as the main source point for PAHs. The evaluation of phenanthrene to anthracene ( P/AN) and fluoranthene to pyrene (FL/PY) ratios permits the assessment of t he pyrolytic, industrial origin of these PAHs, rejecting a second possible source of hydrocarbons (i.e., an oil-pipeline terminal, situated near the s teelmaking factory). Graphical drawing of the total PCB iso-concentrations reveals a different source-point for this other category of very persistent pollutants.