Multigenerational effects of copper nanomaterials (CuONMs) are different of those of CuCl(2): exposure in the soil invertebrate Enchytraeus crypticus

Nanomaterials (NMs) are recommended to be tested in longer term exposures. Multigenerational (MG) studies are scarce and particularly important because effects can be transferred to the next generation. The current risk assessment framework does not include MG effects and this is a caveat for persistent materials. Here, the effects of copper NMs (CuONMs) and copper salt (CuCl(2)) were assessed in a MG exposure (4 generations in spiked soil + 2 generations in clean soil, F1 to F7 generations in total), with the standard soil model Enchytraeus crypticus, using relevant reproduction test effect concentrations (EC(10), EC(50)), monitoring survival and reproduction. This represented ca. 1 year continuous exposure tests. MG effects varied with effect concentration and test materials: CuONMs caused increased toxicity for EC(10) exposed organisms (EC(50) did not change), and transfer to clean media reset effects, whereas CuCl(2) reduced toxicity for EC(10) and EC(50), but the transfer to clean media “revived” the initial effects, i.e. close to EC(50) levels in F7. Clearly CuONMs and CuCl(2) cause different mechanisms of toxicity or response in the long term, not predictable based on short term or one generation studies. The present contributes for the improvement of risk assessment, adding important information for the long term exposure and effects.