Heavy Metal Concentrations in Water, Sediments and Mollusc Tissues

The highest concentrations of heavy metals (Cu, Pb, Zn, Mn, Co, Ni, Cd, and Cr) were found in water, sediment and molluscs of the Malkų Bay and the Smeltelė River. It was determined that after dredging the toxic sediment there was a noticeable decrease of heavy metals in sediment and molluscs from the Malkų Bay. However, low concentrations of heavy metals were found in the Vilhelmo Channel near Klaipėda waterworks. In the same channel near Dreverna the concentrations of heavy metals were much higher and that was associated with the presence of silt in the sediment. This study shows that bioaccumulation of heavy metals in mollusc tissues is dependent not only on their concentration in water but on many other factors as well.