AbstractsBiology & Animal Science

Polymetal contamination is found throughout the environment. Though studies on single metal uptake are thorough and complex, taking into account different uptake routes and species, they do not take into account the effect trace metals may have on each other. It is the aim of this study to add to this pool of knowledge. The focus of this investigation is zinc, cadmium and copper. To understand why these trace metals were chosen another important aspect is included: uptake channels which zinc and cadmium share but copper does not, leading to competitive and non-competitive uptake. This was investigated by designing and performing an uptake experiment on the species Gammarus pulex collected from a stream near Østrup. 24 hours mixed trace metal exposures were carried out to find the effect of cadmium and copper on zinc uptake. Tissue burdens were measured in the AAS facility at Roskilde University in order to obtain uptake rates. The results were analyzed using statistical software SPSS to perform an ANOVA, which showed there is no significant competition between any of the metals in mixture. While this was expected in mixtures containing copper, due to great variance in the data the result was similar for cadmium. However, when comparing the slopes of the regression lines, and therefore their uptake rate constants, it could indicate that zinc competes with cadmium. The uptake rate constant of zinc when in mixture with cadmium is zero, and therefore it can be seen that cadmium inhibits the accumulation of zinc. The uptake rate constant of zinc when in mixture with copper showed to be almost equal to that of zinc alone, suggesting no competition between the two metal ions. The mortality noted in the experiment is believed to be caused by the overestimation of the copper LC50, but curiously, high concentrations of zinc seem to have an antagonistic effect on copper toxicity.