Polycyclic aromatic hydrocarbons in surficial coastal sediments of the Ligurian Sea

Surface sediment was collected from 75 sites all along the coast of the Ligurian Sea and analysed for the 14 polycyclic aromatic hydrocarbons (PAHs) listed as priority pollutants by the US EPA plus 2 alkilated congeners. Total PAH concentrations varied widely, from lower than detection limits to 26247 ìg kg-1. Maximum values correspond to the transects of Genova Punta Vagno, Finale Ligure, Genova Polcevera, in the order. The spatial distribution of PAHs suggested that they derive predominantly from urban and industrial wastes and that discrete point sources are responsible for the highest contamination. The relative abundance of individual PAH compounds suggests that high temperature combustion processes are the predominant source of PAH contamination, even though at some sites the presence of a petrogenic component is significant. The distribution appears sometimes dependent on sediment characteristics, but not on a general scale. Comparison with numerical effects-based sediment quality guidelines indicate that most of the sites have levels of PAH which are predicted not to be harmful. Acute biological effects may occur only in one case, where ERM guidelines are exceeded.