Accumulation of heavy metals by family Lymnaeidae representatives as response to anthropogenic pollution critical levels of South Ural reservoirs

Abstract

The features of heavy metals accumulation by Lymnaea fragilis and L. psilia were researched for the aerate emission polluted area of Karabash copper-smelting manufacturing (Southern Ural). These features are concluded with selective redistribution of heavy metals between soft tissues and the shell of Lymnaea. The heavy metals accumulation takes place by three independent tendencies: water soft tissues, water shell and soft tissues shell. The heavy metals content levels a thousand times exceed the physiological norm in soft tissues while in shell they exceed manifold. In the first place manganese and iron are accumulated while the cobalt, cadmium and molybdenum are finalizing the researched rank of accumulation. It has been ascertained that more biophil manganese are accumulated in mollusk soft tissues more than in other metals, while slightly less biophil iron is accumulated in shell, mainly in surface layers. For soft tissues and shell different ranks of heavy metals accumulation are observed, but these ranks are similar for different habitats, thus qualitative biogeochemical similarity is observed. The heavy metals accumulation in the system water soft tissues shell can help to estimate the extent of the metal environment pollution as well as local biophility of this metal. The adaptive response of pond snails to anthropogenic pollution is that there are more of them in less polluted reservoirs and less in more polluted reservoirs. It has been confirmed, that high heavy metals concentration and low pH level in reservoirs leads to death and absolute absence of these mollusk species.