Responses ofFolsomia 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 range of elevated soil copper concentrations under two different contamination histories. These results were compared with the in situ abundance of F. fimetaria 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 the experiment. Using soil from a field site contaminated with copper more than 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 juvenile clutches were also indicated. The abundance of F. fimetaria showed no change with soil copper concentrations during the first year (spring sampling) of in situ observations. During the second year (autumn sampling), a reduced number per area was observed with increasing soil copper concentrations. Both the presence and abundance of other euedaphic collembolans generally exhibited distribution patterns similar to those of F. fimetaria. Thus, the contamination history and the toxicological endpoint were very important for interpreting the outcome of the standard laboratory toxicity test. Laboratory studies to some extent reflected the in situ abundance, but this depended on the contamination history and the field sampling time. Laboratory experiments using new copper-spiked soil provided the lowest effect levels.