European Observatory for Nanomaterials

Case study successfully applies grouping and read-across for nano titanium dioxide

The Organisation for Economic Co-operation and Development (OECD) has published a case study by the European Union Joint Research Centre (JRC) on grouping and read-across for the genotoxicity of nano titanium dioxide. The case study explores the practical application of the European Chemicals Agency’s Read-Across Assessment Framework to nanoforms.

Helsinki, 26 September 2018 – The case study applied the workflow for grouping and read-across proposed in ECHA’s REACH guidance update for nanomaterials. It explored the extent to which ECHA’s Read-Across Assessment Framework (RAAF) is applicable to nanoforms for identifying sources of uncertainty associated with the read-across. The purpose of the read-across exercise was to determine the genotoxic hazard potential of two nano-TiO2 target substances based on in vitro comet assay results from other TiO2 nanoforms.

Although the case study successfully evaluated the confidence in read-across argumentation for nanomaterials, some nanospecific issues were identified for further clarification. In particular, the concept of similarity which, according to the study, cannot be based solely on the structural similarity of nanomaterials.