"NanoCRED: A transparent framework to assess' the regulatory adequacy of ecotoxicity data for nanomaterials – Relevance and reliability revisited", by Hartmann, et al., was released in March 2017 (Science Direct). The authors examine ecotoxicity testing and ask the question of whether or not these tests are applicable to nanomaterials. They question the standard procedures used for ecotoxicity testing being used for nanomaterials because these procedures were developed for conventional (soluble) chemicals; however, nanomaterials are often insoluble or only partly soluble in water and tend to behave differently than soluble chemicals in ecotoxicity test systems. The evaluation of nanomaterials as presented in their paper is based on an approach by Moermond et al. (2016) for conventional chemicals and involves an adaptation of the Klimisch method (Klimisch et al., 1997). By combining these approaches, the reliability and relevance of the ecotoxicity testing of nanomaterials are made equally important. Specific reliability and relevance criteria for their approach are available in the article.