Measurement of environmental trace-metal levels in Mediterranean coastal areas with transplanted mussels and DGT techniques

Mussels (Mytilus galloprovincialis) and diffusive gradients in thin films (DGT) devices were deployed together for three one-month periods in coastal waters of Sardinia (Italy), in order to assess the levels of Cd, Cu, Ni, and Pb in areas differently affected by anthropogenic activities. DGT devices were more sensitive than mussels in detecting differences in metal concentrations between sites, while interpretation of the biomonitoring data revealed difficulties related to the biotic and abiotic factors that can influence the measurements. Regression analysis showed a significant correlation between Cd and Pb concentrations measured in the mussel tissues and bioavailable metal levels in seawater. Moreover transplanted mussels did not accumulate Cu and Ni following pre-exposure, although DGT showed significant concentrations of bioavailable forms of these metals in seawater. The results provided an estimate of the water quality with respect to dissolved metals and pointed out the usefulness of a combination of biomonitoring and DGT techniques for a better understanding of trace metal availability in coastal waters.