ECHA literature review on uses and risks of nanomaterials as pigments
For many nanopigments, not enough data is available to assess the risks and therefore, no conclusions on safety can be drawn at this point in time. There are however some general observations which can be derived.
The study, based on a literature research, intends to investigate the safe use of nanopigments in the occupational setting as well as consumer products on the European market. For this purpose, an inventory of all clearly declared nanopigments which are definitely defined as such, was created. This list included 81 substances in total. The authors highlight that, due to an agreement to include new requirements for the reporting of nano-scale substances, a more comprehensive inventory of nanomaterials, including pigments, will arise in the near future. The hazard and exposure assessments were made difficult by a lack of data on toxicology and exposure, respectively. In both cases, this stems mostly from the wide variations of different nano-sized pigments and their unique properties, as much as the lack of standardized testing for such a broad variety of materials. There are however some substances that have been well investigated, such as TiO2, ZnO or Carbon Black, among others. The use of these nanomaterials reaches further than pigments however.
As for exposure assessment, there is only very little experimental data available in the literature. The overall risk assessment and accompanying decision-making is complicated by the lack of available data. The authors identify this as the most important finding, urging for more research in this direction. As general rules, the study concludes that dry pigments are of highest concern because of easy ingestion or inhalation, whereas pigments integrated in matrices are not thought to be a significant risk, unless treated by abrasion. The general conclusion, potential exposure being a potential risk to humans, draws on the precautionary principle.