Bioconcentration and depurationof of copper, cadmium, and zinc mixtures by the freshwater amphipod Hyalella azteca

The uptake and elimination of copper (Cu), cadmium (Cd), and zinc (Zn) by the arnphipod Hyalella azteca during exposure to the metals singly and in various combinations was examined in controlled laboratory experiments. In single metal exposures the accumulation of all metals was rapid and increased with exposure time. Copper elimination was slower compared to that for zinc and for cadmium no elimination was detected after 5 days in clean water. In the two-metal mixtures it appears that the presence of one metal influenced the bioconcentration of the other, since the bioconcentration factor (BCF) for copper was higher in the presence of cadmium than in the presence of zinc and in the case of cadmium, the decrease of K-1 values from cadmium single exposure :to the binary and tertiary mixtures suggests possible inhibition of cadmium uptake by the bother metals. In the,case of the three-metal mixture the situation is less clear, with both increased and decreased BCFs recorded, in comparison to single-metal,and two-metal mixtures, suggesting both stimulation and inhibition of metal accumulation. (c) 2006 Elsevier Inc. All rights reserved.