Characterisation of Nanomaterials with Focus on Metrology, Nanoreference Materials and Standardisation

Abstract

Nanomaterials (NMs) may be seen as a particular group of chemicals that are defined by their size. This chapter provides an overview of NMs and requirements under the Cosmetic Products Regulation (CPR), which was the first piece of EU legislation that explicitly defined NMs. A publicly available “catalogue of nanomaterials used in cosmetic products placed on the EU market” by the European Commission provides an overview of NMs used in cosmetic products. The CPR introduced legal requirements for NMs to ensure their safety, including data for physicochemical characterisation, and labelling of cosmetic products for their content of NMs. The Scientific Committee on Consumer Safety (SCCS) evaluates the safety of NMs in cosmetic products and their ingredients, and the SCCS has issued two guidance documents supporting the assessment of NMs. Those documents include listings of physicochemical properties proposed by the SCCS for identification and characterisation of NMs. In general, physicochemical characterisation of a NM is essential to precisely identify and characterise that material. Furthermore, this information is needed prior to further testing for assessing potential toxicological effects to ensure that conclusions from (eco)toxicological tests will be relevant for other experimental contexts and possibly allow linking the NM’s physicochemical properties with identified adverse effects. Characterisation along the life cycle is desirable as some physicochemical properties depend on the immediate surroundings. Different datasets for physicochemical characterisation of NMs have been suggested both in a regulatory and research context, and an overview of datasets is presented here. They all include properties that are beyond the standard dataset for chemicals and are thought to be of particular relevance for NMs. To achieve a comprehensive characterisation and to compensate for the weaknesses of individual methods, the measurement of a property should, where possible, be made using several methods. The chapter highlights the need to develop and agree on methods for physicochemical characterisation; regulatory methods are developed by the OECD test guidelines programme and ISO complements such methods by providing standardised measurement techniques.