Concentrations of Fe, Mn, Cu, Zn, Pb, Ni, Cd, and Co in molluscan shells and associated surface sediments from four sites on the Gulf of Aqaba and Red Sea coasts, Egypt, were measured by using atomic absorption spectrophotometer. The results revealed an apparent difference in the ability of each species regarding accumulating heavy metals in its shell. These results showed that Tridacna squamosa has the highest accumulation ability for Pb, Ni, and Zn, and Chama pacifica has the highest accumulation capability for Co and Cd, whereas Periglypta reticulata has the highest accumulation ability for Cu. The results also showed that there is a positive correlation between the concentration of Cu, Zn, Pb, and Ni and the size of shell. Simultaneously, there is a negative correlation with Fe, Mn, Co, and Cd. The results of bio-accumulation of molluscan species were consistent with the enrichment factors for sediments, where the Hurghada site was extremely enriched with Pb and very enriched with Cu, Zn, and Ni. Moreover, the Quseir site was extremely enriched with Cd and very enriched with Pb. The Um al-Sid site was severe enriched with Cd and Pb. Meanwhile, the Ras Mohamed site was severe enriched with Pb and nearly unpolluted with other metals. Heavy metals can enter the studied ecosystem by terrigenous and anthropogenic sources as a weathering process of the nearby beaches and mountains, ship maintenance, industrial activities, wastewater, and traffic exhaust.
Keywords: Bio-accumulation; Environmental indicators; Molluscan shells; Trace elements.