Effects of temperature on the relative toxicities of Cd, Cu, Pb, and Zn to Folsomia candida (Collembola)

EC50s for cadmium, copper, lead, and zinc were determined for juvenile production of Folsomia candida Willem, 1902, at 25, 20, and 15 degrees C in a standard laboratory test system. Juvenile production of F. candida was too low at 25 degrees C for reliable EC50-reproduction values to be determined. The EC50-reproduction values (micrograms g-1) for cadmium, copper, and zinc were similar at both 20 and 15 degrees C (20 degrees C: Cd, 590; Cu, 700; Zn, 900; 15 degrees C: Cd, 540; Cu, 640; Zn, 590). Corresponding values for lead were considerably higher (20 degrees C: Pb, 2790; 15 degrees C: Pb, 1570). In aerially contaminated field sites adjacent to primary zinc smelters, zinc is invariably present in surface soils at concentrations of at least 50 times those of cadmium. The similarity of the EC50-reproduction values for cadmium and zinc in F. candida at 20 and 15 degrees C determined in this study strongly suggests that deleterious effects of mixtures of these metals on populations of Collembola in such sites can be attributed to zinc rather than cadmium.