Composti organostannici

The southern Venice lagoon has been affected by an increase of several anthropogenic activities (dockyards, harbours and marina) which have contributed to enrich sediments with metals in the recent years. The contamination of metals in the surface sediments along with their accumulation in the gastropod Nassarius reticulatus were investigated. Highest metal concentrations of Cu, Zn, Pb and Cr found in the dockyards and marina sites suggest their possible past and recent use as biocides in the antifouling paints. The enrichment factor (EF) showed highest values (EF410) near the dockyards, harbour and marina sediments for Cu, where the use of the antifouling tin free paints has been more relevant. High levels of metals were also found in the target gastropods. Biota-Sediment-Accumulation-Factor and correlation analyses pointed out a significant mobilization of metals, particularly Cu, from sediments and their accumulation in the gastropods.

The release of tributyltin (TBT) from maritime traffic represents one of the main problems of direct, diffuse, and continued contamination of the marine environment. In the present survey, the concentrations of TBT and dibultytin (DBT) in brackish waters, sediments, and the gastropods Nassarius nitidus were evaluated in order to estimate the contamination of the southern part of the Venice lagoon. TBT and DBT were determined by GC–MS/MS. Recent contamination of TBT was found in brackish waters near marinas, whereas the highest concentrations of TBT and DBT were observed in surface sediments at dockyards and harbours. High content of organotin in the gastropods sampled near the dockyards, harbours, and marinas showed a mobilisation from the sediments through the food web. The present study allowed assessment of whether, despite the ban on the use of TBT paints, waters, sediments, and biota were still being contaminated by organotin compounds in the southern Venice lagoon.