BayCEER Workshop 2008

Sub-chronic effects of cadmium exposure on its bioaccumulation and calcium metabolism in the bivalve Anodonta anatina (Linnaeus 1758)

The sub-chronic exposure of freshwater mussels to Cd at low levels may influence their growth, survival, reproduction and population dynamics. Mussels were exposed to algae- and water-borne ¹¹¹Cd for 35 days and allowed to depurate for 120 days. Body fluids and tissue samples were taken during both phases to determine total Cd²⁺, the ¹¹⁴Cd/¹¹¹Cd ratio and Ca²⁺. Bioaccumulation and distribution of Cd²⁺ as well as its effects on Ca metabolism in the freshwater bivalve Anodonta anatina, both tissue-specific and time dependent, were examined. Increase of exogenous Cd, i.e. newly incorporated Cd due to exposure experiment, occurred in all tissues during the exposure period, with the highest levels in kidneys, accompanied by altered Ca²⁺ profiles in all body compartments. Exogenous (kidney and mantle) and endogenous Cd²⁺ (kidney) increased during depuration due to its redistribution between organs. This shows the potential of using the stable isotope ¹¹¹Cd in studying Cd kinetics and dynamics. Loss of exogenous Cd during depuration was low, mainly from the digestive gland. Correlations between Ca²⁺ and exogenous as well as total Cd²⁺ in kidney together with the alteration of Ca profiles in all compartments suggest that derangement of Ca metabolism is the major primary effect of low-level Cd toxicity in A. anatina.