Using AOP-Wiki to support the ecotoxicological risk assessment of nanomaterials: first steps in the development of novel adverse outcome pathways

Abstract

Currently, the development of adverse outcome pathways (AOPs) that are relevant for nanomaterials (NMs) is focusing mainly on their human toxicity. However, there is an additional component of nanosafety that needs to be considered in the context of the risk assessment of this class of materials – their ecotoxicity. Assessment of the environmental impact of a substance is as important as that of the impact on humans, as there is a risk of NM release into the environment throughout the entire life cycle of a product. For this reason, it is necessary to also conduct ecotoxicological studies aimed at developing environmentally relevant AOPs. Here, we have made an effort to integrate data and knowledge available in the AOP-Wiki and scientific publications aimed at making the first step towards developing an AOP-based strategy for assessing the ecotoxicity of NMs. We have identified AOPs for which the most nano-relevant information is available and recommended it as a starting point for the development of ecotoxicological AOPs for NMs, and for the organisation of the existing pathways into adverse outcome networks (AONs), thereby identifying KEs that are points of convergence or AOs for which there are multiple pathways. AONs may also help in focusing future research, highlighting where targeted assays are needed to discriminate between different potential pathways/mechanisms of toxic action.