Interactions of Soil Species Exposed to CuO NMs are Different From Cu Salt: A Multispecies Test.

Although environmental effects are mostly assessed via standard individual species the ecological relevance of multispecies testing is well-recognized and highly recommended. Hence, the effect of copper oxide nanomaterials (CuONM) and CuCl2 were assessed using the validated soil multispecies system (SMS). Besides the individual species (IS) "standard" tests for all, a predation study was done. Toxicity was higher in the SMS than in the IS, and longer exposure showed increased toxicity. The predator ( Hypoaspis aculeifer) preyed most on smaller species, but the net biomass consumed was similar across species. Internal Cu in Folsomia candida reached ca. 140 μg Cu/g dry weight, fluctuating over time, especialy for CuCl2. Copper was mostly bound to soil components for both Cu forms (<0.2% of the total Cu in soil solution, < 0.007% on the ionic form, but the soil solution content increased with the total added concentration). Hazard Concentrations (HC5) showed higher toxicity and more similarity between Cu forms at longer-term exposure. Risk of NMs is relatively limited at present (IS based instead of SMS) with short exposure times (i.e., longer is required) and too few IS tested. The impact of species interactions is highlighted and is of key importance to include in ecosystem hazard prediction.