CADMIUM UPTAKE AND BIOACCUMULATION IN XENOPUS-LAEVIS EMBRYOS AT DIFFERENT DEVELOPMENTAL STAGES

The uptake of cadmium in Xenopus laevis embryos was studied by exposin g them to solutions containing cadmium concentrations ranging from 0.1 to 2 mg Cd2+/L at seven developmental stages for 72 h. The uptake val ues were from 0.0027 mu g Cd2+/embryo (two blastomeres stage) to 0.081 mu g Cd2+/embryo (hindlimb bud distinct stage). During early developm ental stages, a limited permeability to cadium could play a significan t role for the survival of embryos. At the last developmental stage ev aluated there was a significantly higher uptake of cadmium simultaneou sly with a very significant increase in the resistance against cadmium toxicity. The cadmium bioaccumulation factor (BF) ranged from 5 to 46 0. As a general pattern at all developmental stages the BF was higher in embryos exposed to the lower cadmium concentration, and as developm ent advanced the BF increased. (C) 1998 Academic Press.