Soil ecotoxicity standard tests for invertebrates are usually limited to the assessment of endpoints like survival and reproduction. Adverse effects may occur at other developmental stages, e.g. embryo development, hatching or growth. The species Enchytraeus crypticus is a model organism in the standard soil ecotoxicology test, where survival and reproduction are assessed. In the present study we optimized the test method to include additional endpoints. The proposed test started with synchronized age organisms', and included additionally hatching success, growth, maturation status and full life cycle. This allowed for the calculation of cocoon production and population growth rate. Results indicated that Cd is embryotoxic, main effect occurs on the embryo developmental stage and maturity. Further, the full life cycle test can discriminate between pre- and post-embryo formation. The increased sensitivity and full life cycle detail level makes it potentially useful for novel materials e.g. nanomaterials where the mode of action and hence effect target is unknown.

No abstract

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 (CuCl2) 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 (EC10, EC50), 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 EC10 exposed organisms (EC50 did not change), and transfer to clean media reset effects, whereas CuCl2 reduced toxicity for EC10 and EC50, but the transfer to clean media “revived” the initial effects, i.e. close to EC50 levels in F7. Clearly CuONMs and CuCl2 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.

Nanoparticles (NPs) such as nickel (Ni) are widely used in several applications. Nevertheless, the environmental effects of Ni NPs are still poorly understood. In the present study, the toxicity of Ni NPs and nickel nitrate (NiNO ) was assessed using the standard test species in soil ecotoxicology, Enchytraeus crypticus (Oligochaeta), in a full life cycle test, adding the endpoints hatching, growth, and time to reach maturity, besides survival and reproduction as in the standard Organisation for Economic Co-operation and Development Guideline 220 and/or International Organization for Standardization 16387. For Ni NPs, the Ni in soil and in soil solution was concentration- and time-dependent, with a relatively higher soil solution content in the lower and shorter exposure concentrations and times. Overall, NiNO was more toxic than Ni NPs, and toxicity seemed to occur via different mechanisms. The former caused reduced hatching (50% effect concentration [EC50] = 39 mg Ni/kg soil), and the negative effects remained throughout the life cycle, in all measured endpoints (growth, maturation, survival, and reproduction). For Ni NPs, hatching was the most sensitive endpoint (EC50 = 870 mg Ni/kg soil), although the organisms recovered; that is, additional endpoints across the life cycle showed that this effect corresponded to a delay in hatching because organisms survived and reproduced at concentrations up to 1800 mg Ni/kg soil. On the other hand, the lowest tested concentration of Ni NPs (100 mg Ni/kg soil) caused reproduction effects similar to those at higher concentrations (1000 and 1800 mg Ni/kg soil). The present results show that the potential implications of a nonmonotonic dose response should be considered when assessing the risks of Ni NP exposure in soil. Environ Toxicol Chem 2017;36:2934-2941. © 2017 SETAC.

General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.