Distribution and sources of polycyclic aromatic hydrocarbons (PAHs) in surface sediments of some Italian lagoons exploited for aquaculture and fishing activities

Abstract

The concentrations of 16 PAHs in surface sediments collected from four Italian
\nlagoons, exploited for aquaculture and fishing activities, during the period
\n2004–2007, were analysed. Some molecular ratios and Pearson correlations were
\nused in order to estimate the origin of the pollution and similar transport of PAH
\nsources. Principal Component Analysis (PCA) and Cluster Analysis were used in
\norder to highlight dissimilarities among sampling sites. Concentrations of total
\n16 PAHs varied significantly among the lagoons as well as within the same basin.
\nSediments of Orbetello lagoon showed the highest level of contamination
\n(mean of 98.78 ng g1), followed by that in Santa Giusta (48.15 ng g1), Lesina
\n(31.06 ng g1) and Varano (25.19 ng g1). These results were linked to the greater
\nindustrialisation and urbanisation of the catchment area of both Orbetello and
\nSanta Giusta compared with Lesina and Varano. A considerable predominance
\nof 4-rings PAHs was observed for Lesina (52%,), Varano (77%), Orbetello (50%)
\nand Santa Giusta (57%) and Pyrene was the dominant compound. On the other
\nhand, phenanthrene is the dominant compound of low molecular weight
\ncontaminants for all the studied lagoons. A meaningful pyrolytic contribution
\nto pollution was found in the sediments of Lesina lagoon, dominated by
\nbenzo[a]pyrene (7.27 ng g1) and benz[a]anthracene (4.14 ng g1), due to intensive
\ntraffic. For Varano, an evident petrogenic contamination was observed along the
\nwestern area, due probably to accidental oil spillage. All 16 PAHs were found to
\nbe correlated in Orbetello and Santa Giusta lagoons and the compounds present
\nin Santa Giusta sediments, near the urban centre, were shown to be mainly
\nof pyrolytic origin. A much more complex situation was observed in Orbetello,
\nwhere a mixed pattern of pyrolytic and petrogenic inputs was observed.