SEDIMENT FEATURES AND HEAVY METAL LEVELS IN FOUR AREAS OF SARDINIA DEVOTED TO BIVALVE CULTURE CARATTERISTICHE DEI SEDIMENTI E LIVELLI DI METALLI PESANTI IN QUATTRO AREE DELLA SARDEGNA IDONEE ALL’ALLEVAMENTO DEI BIVALVI

Sediment characteristics and Cd, Cu, Mn, Pb and Zn concentrations were assessed in the lagoons of Marceddì, Calich and Porto Pozzo, and in the inner part of the Gulf of Olbia. Sediment of the zones examined were quite similar, except for the Calich lagoon that showed the higher content of total organic carbon. High values of Cd, Pb and Zn were detected in the sediments of the Marceddì lagoon, while remarkable levels of Cu and Mn were found in the Calich lagoon and in the Gulf of Olbia