Accumulation of heavy metals in freshwater molluscs with special emphasis on utilizing them as biomonitors in the aquatic environments

Abstract

A field study was conducted to evaluate the potential of using some of the freshwater moluscan species as a bioindicator for the heavy metals in Mit Yazid Canal and Belay Drain, Gharbia Governorate. Based on the field visit, six of moluscan species were collected from Mit Yazid Canal, namely; Mutela sp., Coelatura aegyptiaca and Corbicula fluminea (filter feeder bivalves) and Melanoides tuberculata, Bellamya unicolorand Lanistes carinatus (bottom feeder gastropod snails). On the other hand, only one species of L. carinatus was collected from the polluted drain (Belly Drain). In the unpolluted canal (Mit Yazid Canal), the present result showed that there were statistical differences between concentrations of the heavy metals (aluminum, barium, cadmium, cobalt, copper, iron, manganese and vanadium) among the soft tissues of moulscan species. But, the heavy metals (chromium, lead, nickel and zinc) were uniformly distributed. Also, the present result showed that aluminum, copper, nickel, zinc, iron and lead were highly accumulated in the soft tissues more than the other metals. In addition, the present result showed that the bioaccumulation of all trace metals in both adult and juvenile, Bellamya unicolor was statistically the same except for vanadium. In the polluted drain, the bioaccumulation of the investigated heavy metals in the soft tissues of L. carinatus tended to be high when it compared with their bioaccumulation in the soft tissues of the same species in the unpolluted canal except for the vanadium. Furthermore, the present result showed a positive correlation between the accumulations of trace metals in different moluscan species with their concentration in the sediments.