EVALUATION OF MOLLUSC AS SENSITIVE INDICATIOR OF HEAVY METAL POLLUTION IN AQUATIC SYSTEM: A REVIEW

A The potential ecological effects of rising levels of heavy metals concentrations in the environment are of great concern due to their highly bioaccumulative nature, persistent behavior and higher toxicity. These chemicals biomagnify in the food chain and impose various toxic effects in aquatic organisms. Molluscs reflect the higher degree of environmental contamination by heavy metals and are the most useful bioindicator tools. Several studies and research work have been cited to establish and evaluate the relationship between metal contents of water column, sediment fractions, suspended matter and mollusc tissue concentrations. The metals body burden in molluscs may reflect the concentrations of metals in surrounding water and sediment, and may thus be an indication of quality of the surrounding environment. The objectives of this work are to gather more information on the use of different species of molluscs as cosmopolitan bioindicators for heavy metal pollution in aquatic ecosystems.