Terrestrial organisms react differently to nano and non-nano Cu(OH) forms.

The application of nanomaterials in agriculture is deemed as a promising strategy to increase the sector's sustainability. Nanopesticides are expected to improve solutions for pest/disease management, while reducing adverse effects to ecosystems, in accordance with the European Green Deal strategy. Hitherto, nanopesticide research has mostly focused on assessing effects to target species or crops, and less attention has been devoted to non-target soil species. In this study, we explored whether three copper hydroxide-based forms (nano and non-nano) show different toxicity and accumulation patterns in two terrestrial invertebrates, the isopod Porcellionides pruinosus and the mealworm larvae Tenebrio molitor. Toxicity and bioaccumulation experiments were performed and time-course toxicity and toxicokinetics analyzed and modelled. We found important differences in copper sensitivity and accumulation: T. molitor was more resistant and able to eliminate copper compared to P. pruinosus. The nanopesticide mostly elicited lower effects for both species. Slower toxicokinetics by the nanopesticide and lower bioaccumulative potential to P. pruinosus must be partially responsible for the differences in toxicity. Although no toxicokinetics differences were found in T. molitor between Cu forms, distinct negative effects on growth must reflect different energetic costs for copper regulation. Even though effects on toxicity and bioaccumulation are species-specific, copper hydroxide-based nanopesticides may cause less adverse effects to soil organisms than conventional products, being a good solution for reducing the environmental impact. CAPSULE: Copper hydroxide-based nanopesticide was less toxic and bioaccumulative to soil organisms than conventional copper hydroxide products, being a good solution for reducing the environmental impact.