Considering Safe and Sustainable by Design alternatives – Environmental Hazards of an agriculture Nano-enabled pesticide to non-target species

Abstract

Nanopesticides (Npes) offer improved efficacy compared to their conventional forms while reducing the usage/application rates, hence being more sustainable options. However, there is still a knowledge gap on the Npes environmental impacts. To support the safety of nano-enabled pesticides, the present study aimed at assessing the toxicity of the commercial Npe NUCOP-M and the active substance copper oxychloride, using the ecotoxicological soil model Enchytraeus crypticus and LUFA 2.2 soil. Bioassays were performed to assess various endpoints within short- to longer-term exposures: avoidance behaviour (2 d), hatching (13 d), survival, reproduction and organisms' size (based on the standard OECD test (28 d), the OECD extension (56 d), and the Full Life Cycle test - FLCt (46 d)). Based on the standard OECD test and its extension, NUCOP-M had a similar level of toxicity as copper oxychloride without indications of increase in toxicity over time (28 versus 56 d). The shorter-term exposures (2 and 13 d) showed higher toxicity for copper oxychloride. The exposure from cocoon stage (FLCt) seemed to provide an adaptative advantage (reduced toxicity) to NUCOP-M. The differences might be related to a slower release of Cu2+ ions from NUCOP-M, which seems to account for the toxicity at longer-term. Based on the recommended application doses (ca. 1.72 mg NUCOP-M kg-1, i.e. 0.62 mg Cu kg-1 in the topsoil) there is no unacceptable risk of NUCOP-M on the enchytraeid population.