Detection of trace elements in the bivalve Ruditapes decussatus from Sardinian coastal lagoons: effects on food safety and pathological findings in target organs

Shellfish can bioaccumulate toxic metals due to their ability to concentrate inorganic contaminants. Since biomonitoring by using bivalve molluscs is currently considered one of the most effective approaches for assessing the degree of pollution of brackish environments, the aims of this PhD thesis were: a) to detect the content of trace elements in the Grooved carpet shell Ruditapes decussatus collected in Sardinian coastal lagoons (Italy) and their effects on food safety; b) to evaluate the pathological findings in its target organs. The concentration of 16 trace elements (Al, Ag, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, Sn, Tl and Zn) was quantified. The legal limits set by European Regulations for Cd, Hg and Pb were never exceeded. Unexpectedly high values for Al and Fe were found. A total of six histopathological alterations were analysed in the digestive gland, gills and kidney following a weighted condition indices approach. Gills show the highest prevalence of lesions than digestive gland, followed by kidney. The clam R. decussatus confirmed the capacity of bivalves as suitable bioindicators of trace elements pollution.The determination of trace elements combined with histopathological analysis, should be a powerful tool in environmental monitoring plans. It is useful for understanding directly the health status of the marine organisms and indirectly the impact which different anthropogenic activities have on shellfish harvested in coastal environments.