Cadmium bioaccumulation studies in the freshwater molluscs Anodonta cygnea and Unio elongatulus

Abstract

1. The effects of cadmium exposure have been studied in two freshwater bivalves, A. cygnea and U. elongatulus. 2. Cadium exposure induces an unremarkable cadmium uptake in the tissues of both the organisms. Thus the low metal concentration in the tissues together with the absence of suffering seem to indicate the presence of some kind of regulation. 3. Cadmium exposure has little effect on copper and zinc levels and distribution indicating in these organisms the presence of little interaction between cadmium and divalent essential metals. 4. The percentage distribution of cadmium, copper and zinc between the two main fractions obtained from Sephadex G-75 varies with metal, organism and tissue suggesting that high molecular weight metal chelating compounds are actually present in the organisms. 5. The detoxication capabilities of different organisms are discussed in relation to the differences found in two closely related freshwater animals.