Utilizzo di nuove tecniche di campionamento passivo di contaminanti prioritari nelle acque marino-costiere della Sardegna (Mediterraneo centro-occidentale)

In the coastal and marine environment a growing number of contaminants are considered dangerous for their ability to damage ecosystems and move along the food chains. The assessment of such pollution, which includes among other polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and heavy metals, is complex and subject to numerous criticisms and suggestions for improvement. The methodology for assessing the quality of surface water is based on water withdrawals on time to entrust the chemical analysis. Many of priority contaminants listed in the Directive "Marine Strategy" 2008/56/EC are however micropollutants present in very low concentrations, often below the detection limit of the methods currently available. Where the concentration of these pollutants exceeds the limits of the law, as in the sediments, it may not be dangerous because this is not bioavailable forms. In this study were tested for marine waters passive sampling techniques. Aqueous concentrations of individual PAHs and PCBs were determined in two coastal sites of marine protected areas (MPAs): Asinara and the La Maddalena Archipelago, Sardinia (Western Mediterranean Sea). The use of semi-permeable membrane devices (SPMDs) enabled the detection of dissolved PAHs and PCBs, even at very low concentrations of (pg L-1, ng L-1) in seawater. The results reveal differences between the two sampling areas related to the concentration of the individual PAHs, which provide information concerning the pollution sources affecting relatively pristine environments. The PCBs were Generally Observed at levels below the detection limits of the method utilized. The concentration of aqueous metal ions cadmium, lead, mercury, nickel, chromium and copper have been investigated in the Santa Gillalagoon (South Sardinia). The use of Diffusive Gradients in Thin Films (DGTs) showed that the concentrations of bioavailable fraction (ngL-1) of all metals monitored were below legal limits. However, the results revealed differences in the concentration of individual metals and provided information concerning the sources of pollution. The passive samplers were useful tools for the assessment of the EQSs and the prevention of pollution in sea water.