Effect of Toxicity of Cadmium on Scale Morphology in Cyprinus carpio (Cyprinidae)

Abstract

Heavy metals, as pollutants of the aquatic environment, form a m a j o r h a z a r d b e c a u s e o f t h e i r t o x i c i t y , p e r s i s t e n c e a n d bioaccumulat ion in the food chains. In this respect cadmium pollution is of global concern (Samiullah 1990). Cadmium finds its way via atmospheric transport into the environment from a number of industries, is a byproduct of fossil fuel combustion and base metal smelting. This biologically non-essential element is highly toxic to aquatic organisms. Adverse effects of cadmium on the liver and kidney of aquatic animals are well documented (Mueller 1993; Singhal and Jain 1997). However, very few studies have been made to unders tand i t s e f fec t on sca le morpho logy o f f i sh . Presently, such a study has been made in Cyprinus carpio. For a s tudy o f cadmium tox ic i ty , t h i s f i s h p r o v i d e s s o m e u n i q u e advantages such as i t s to le rance to tempera tu re var ia t ions , toughness and biennial breeding (Singhal 1995).