The uptake and elimination of copper (Cu), cadmium (Cd), and zinc (Zn) by the amphipod 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 other 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.
Hyalella azteca (Crustacea: Amphipoda), water and sediments from 12 circum-neutral lakes between Sudbury and North Bay in Ontario, Canada were sampled in August 1998 and analyzed for 10 metals including Cu, Zn, Cd, Ni, Pb, Co, Mo, V, Ba and Ti. Statistical analyses showed that concentrations of the metals in H. azteca, water and sediment differed significantly (ANOVA, P<0.05) among lakes (except for Zn and Pb in H. azteca and Mo in water). There was a trend of declining metal concentration, especially for Cu, Ni and Co (in water, Hyalella and sediment), with distance from the smelters indicating the reduced impact of atmospheric pollution. Metal concentrations of lakes (water) in the Sudbury area were found to be lower compared to data from the 1970s and 1980s indicating an improvement in water quality. Metal concentrations in field-collected amphipods compared favorably with those measured in the laboratory in animals exposed to deep-water sediments, provided metal concentrations were not extremely low (e.g., Pb) and that water chemistry differences (e.g., pH) were taken into account for some metals (especially Cd). In general bioaccumulation of metals in H. azteca was predicted better from surface water than from sediment total metal.