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Rossella Di Leonardo, University of Palermo (Italy)
Adriana Bellanca, University of Palermo (Italy)
Andrew Cundy, University of Brighton (United Kingdom)
Salvatrice Vizzini, University of Palermo (Italy)
Rodolfo Neri, University of Palermo (Italy)
Antonio Mazzola, University of Palermo (Italy)
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The urban/industrial area of Palermo (NW Sicily) is an example of contaminated coastal environment with a relatively high influx of unregulated industrial and domestic effluents. Sediment investigation is one useful approach to evaluate the poorly known effect of these inputs on the Palermo Gulf. Two sediment box-cores were collected within the Palermo Gulf in water depths of 100?750 m. The samples were dated by 210Pb and 137Cs, and analysed for concentration of major/trace elements, total polycyclic aromatic hydrocarbon (PAH), total organic carbon (TOC) and for organic carbon and nitrogen isotopic composition. At the coastal station, the heavy metals and PAHs vs depth profiles show a clear increase in concentration with decreasing depth, indicating an increasing contamination over the last 80 years. Concentrations of PAHs and some trace metals (notably Pb, Hg, As, and Cr) appear to be potentially hazardous, grossly exceeding national and international regulatory guidelines. In this site, TOC concentrations are relatively high (0.96-1.17%) and increasing upcore. Organic carbon to total nitrogen (C/N) ratios indicate a dominantly marine origin supporting eutrophication, rather than direct land runoff, as principal carbon source. An increase in primary productivity fuelled by nutrient input is consistent with organic δ13C values increasing over time and showing a positive correlation with C/N ratios. In the same samples, a decrease in δ15N values might imply some contribution of nitrogen-fixing cyanobacteria to the marine productivity. Despite the consistent anthropogenic chemical input into the Palermo Gulf, in a previous work no significant impact was observed on the foraminiferal population. On the whole, results suggest that eutrophication of coastal waters might have reduced the bioavailability of contaminants buried within the sediment.
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