Effect of Metal Mixtures (Cd and Zn) on Body Weight in Terrestrial Isopods

Abstract

The aim of this study was to determine the effect of exposure to cadmium and zinc mixtures on the weight of terrestrial isopods. Experiments were conducted using uncontaminated specimens of P. laevis. The isopods were exposed to various concentrations of cadmium and zinc sulfate in single- and mixed-metal experiments. The mean weight of the unexposed isopods in the control group increased over the 6 weeks of observation. It was concluded that cadmium and zinc, administered separately, had a negative effect on the weight of P. laevis. The weight change (gain or loss) of P. laevis in the exposures to mixtures of cadmium and zinc sulfate were different from those of woodlice where Cd and Zn were administered separately. Combination of the lowest concentrations of Cd and Zn (20 and 1000 mg · kg^-1) produced a stimulating effect compared to the control. Weight changes of the other two combinations of Cd and Zn (80/4000 and 160/8000 mg · kg^-1) showed no differences from those of the control, and weight changes of woodlice exposed to Cd and Zn mixtures were mostly the same as those of the control over the 6-week exposure period. It can thus be concluded that mixtures of Cd and Zn have an antagonistic effect on each other in terms of weight of P. laevis.