The nanoGRAVUR grouping framework with 25 quantitative case studies

W. Wohlleben

Keywords: risk assessment, occupational safety, consumer safety, environmental effects, grouping


Nanomaterials are commercialized in a myriad of grades that are optimised in composition, size, shape, coating for specific applications. As the scope of the different reporting and registration schemes in EU countries, in the USA and Canada includes nanoforms of widespread materials, the need arises to evaluate if the different grades can be grouped for risk assessment purposes. Additionally, there is necessity to ensure the safe use of innovative nanomaterials early during R&D, ideally by read-across without animal testing. The project nanoGRAVUR (2015-2018) was funded by the German Federal Ministry of Research and by industry, and comprised partners from academia, regulatory agencies and industry. nanoGRAVUR developed a framework for grouping of nanomaterials. Different groups may result for each of the three distinct perspectives of Occupational, Consumer and Environmental safety. Each is assessed by a risk matrix that integrates hazard and exposure indicators. The indicators are harmonised between the three perspectives and are are based: in tier 1 on intrinsic physical-chemical properties (what they are) or GHS classification of the non-nano form (GHS human tox, GHS ecotox, GHS physical hazards); in tier 2 on extrinsic physical-chemical properties, in-vitro assays and release measurements from nano-enabled products (where they go; what they do); in tier 3 on case-specific testing, potentially including in-vivo studies to substantiate the similarity within groups or application-specific release testing The methods developed by nanoGRAVUR fill several gaps highlighted in the Steinhäuser & Sayre (2017) reviews, and are useful to implement both the ECHA concept of nanoforms as well as the EPA concept of discrete forms. The increased predictivity, especially for biodissolution, transformation, mobility and reactivity, resolves the few false positives of the ECETOC DF4nanogrouping. Case studies include families of Fe2O3, SiO2, CeO2, organic pigment, ZnO, Cu, TiO2 (nano)forms. Benchmark nanomaterials and benchmark nano-enabled products are essential to achieve reproducible groupings across different labs with slightly differing equipment (e.g. for dustiness, sanding, dispersion stability, reactivity).