Responses of Folsomia fimetaria (Collembola : Isotomidae) to copper under different soil copper contamination histories in relation to risk assessment

The collembolan Folsomia fimetaria L. was exposed in the laboratory to a ra nge of elevated soil copper concentrations under two different contaminatio n histories. These results were compared with the in situ abundance of F. f imetaria in a copper-contaminated field site. In the laboratory studies, an EC10 of 337 mg Cu/kg was observed for soil spiked with copper 1 d before t he experiment. Using soil from a field site contaminated with copper more t han 70 years previously, no effect was observed at concentrations as great as 2911 mg Cu/kg. Reproduction was threefold more sensitive than mortality or growth. Differences in copper sensitivity between sexes and between juve nile clutches were also indicated. The abundance of F. fimetaria showed no change with soil copper concentrations during the first year (spring sampli ng) of in situ observations. During the second year (autumn sampling), a re duced number per area was observed with increasing soil copper concentratio ns. Both the presence and abundance of other euedaphic collembolans general ly exhibited distribution patterns similar to those of F. fimetaria. Thus, the contamination history and the toxicological endpoint were very importan t for interpreting the outcome of the standard laboratory toxicity test. La boratory studies to some extent reflected the in situ abundance, but this d epended on the contamination history and the field sampling time, Laborator y experiments using new copper-spiked soil provided the lowest effect level s.