Guidance Document on Aquatic and Sediment Toxicological Testing of Nanomaterials, Second Edition

This document provides guidance for aquatic (including sediment) ecotoxicity testing of manufactured nanomaterials (MNs) to determine their hazard. The definition of MNs as having one dimension between 1 and 100 nm is generally adopted. However, the guidance provided here should also be relevant for colloidal (nano) particles (e.g. 1 to 1000 nm) with primary or aggregate or agglomerate sizes greater than the range for MNs. The guidance focuses on freshwater aquatic and sediment toxicity test methods described in the OECD Test Guidelines. More specifically, this guidance document addresses practical aspects of carrying out valid tests with MNs including the interpretation and reporting of the results, and addresses specific issues. It also addresses modifications or additions to OECD TG procedures intended to incrementally improve the accuracy, intra-laboratory repeatability and inter-laboratory reproducibility of test results. While the focus was specifically on adapting the OECD TGs for reliable MNs testing, the methods and principles discussed herein are likely more widely applicable to aquatic toxicity test methods published by other organisations. This is the second edition of the guidance document originally published in 2020 (No. 317 in the Series on Testing and Assessment), which has been enriched with annexes specific to the conduct of TG 201, TG 202 and TG 203, and based on experience gained from testing MNs.