Assessing the significance of Ruditapes philippinarum as a sentinel for sediment pollution: Bioaccumulation and biomarker responses

The present study assessed whether the bivalve Ruditapes philippinarum may be appropriately deployed as a bioindicator in monitoring transitional environments, in terms of bioaccumulation potential and biomarker responses. The concentrations of trace metals, PAHs and PCBs were determined in sediments and clam tissue, and biomarkers were estimated at various levels of biological complexity (i.e. metallothioneins, lipofuscins, survival-in-air and reburrowing behaviour). Sediments and clams were collected biannually in 2004 and 2005 at eight sites within Venice lagoon, which were influenced differently by natural and anthropogenic impacts. Results highlighted that the broad variations of pollutant concentrations in sediments were not consistent either with the body residuals or with the biomarker responses. Consequently, on the basis of the observed weak responsiveness and sensitivity to anthropogenic stressors we suggest a more cautious use for R. philippinarum as sentinel organism, at least in estuarine sediments in the north Adriatic transitional areas. - Highlights: ► Clams were collected biannually at eight sites in the Venice lagoon for two years. ► Heavy metals, PAHs and PCBs were evaluated in sediments and clam soft tissues. ► Biomarkers were estimated at various biological levels from biochemical to organism. ► Contaminant levels in sediments were not consistent with body residuals and biomarkers. ► A cautious use for R. philippinarum as a sentinel organism is suggested. - Biological and chemical results on Ruditapes philippinarum used as a bioindicator suggested its cautious use in biomonitoring transitional environments.