ADAPTING OECD AQUATIC TOXICITY TESTS FOR USE WITH MANUFACTURED NANOMATERIALS: KEY ISSUES, CONSENSUS RECOMMENDATIONS, AND DATA GAPS
Elijah J. Petersen, Alan Kennedy, Greg Goss, Ho Kay, Jamie Lead, Shannon Hanna, Kerstin Hund-Rinke, Brian Mader, Nicholas Manier, Pascal Pandard, Edward Salinas, Kathrin Schwirn, Doris Voelker
The unique or enhanced properties of manufactured nanomaterials (MNs) suggest that their use in nano-enabled products will continue to increase in the future. This will result in increasing potential for human and environmental exposure to MNs, during manufacturing, use, or disposal of nano-enabled products. Scientifically based risk assessment for MNs necessitate development of reliable, standardized hazard testing methods such as those provided by the Organization of Economic Cooperation and Development (OECD). Currently, however, there is no unified guidance on how to best address testing issues specific to MN particulate, fibrous, and colloidal properties. This paper summarizes the findings from an expert workshop convened to develop a guidance document to address difficulties encountered when testing MNs using aquatic and sediment test guidelines. The 23 participants from 6 countries identified critical components of test guidelines that will require additional or modified guidance for reliable MN testing. These include preparation of MN dispersions, MN dose metric measurements, the feasibility and challenges associated with maintaining and monitoring exposure levels, and the need for reliable methods to quantify MNs in water and sediment. We include a discussion of topics for which consensus was and was not achieved, identify key knowledge gaps that hinder development of prescriptive aquatic toxicity testing guidance for MNs, and recommend research topics to mitigate these gaps to facilitate development of a broadly- applicable guidance document.