Grouping and Read-Across Approaches for Risk Assessment of Nanomaterials

Abstract

Physicochemical properties of chemicals affect their exposure, toxicokinetics/fate and hazard, and for nanomaterials, the variation of these properties results in a wide variety of materials with potentially different risks. To limit the amount of testing for risk assessment, the information gathering process for nanomaterials needs to be efficient. At the same time, sufficient information to assess the safety of human health and the environment should be available for each nanomaterial. Grouping and read-across approaches can be utilised to meet these goals. This article presents different possible applications of grouping and read-across for nanomaterials within the broader perspective of the MARINA Risk Assessment Strategy (RAS), as developed in the EU FP7 project MARINA. Firstly, nanomaterials can be grouped based on limited variation in physicochemical properties to subsequently design an efficient testing strategy that covers the entire group. Secondly, knowledge about exposure, toxicokinetics/fate or hazard, for example via properties such as dissolution rate, aspect ratio, chemical (non-)activity, can be used to organise similar materials in generic groups to frame issues that need further attention, or potentially to read-across. Thirdly, when data related to specific endpoints is required, read-across can be considered, using data from a source material for the target nanomaterial. Read-across could be based on a scientifically sound justification that exposure, distribution to the target (fate/toxicokinetics) and hazard of the target material are similar to, or less than, the source material. These grouping and read-across approaches pave the way for better use of available information on nanomaterials and are flexible enough to allow future adaptations related to scientific developments.

Application of Bayesian networks for hazard ranking of nanomaterials to support human health risk assessment

“…BN allows combination of material and bio-physical interaction properties in a quantitative manner and can be applied as a stand-alone concept. The unique feature of BN to fill data gaps of NMs of which little data is available (e.g., read across) can also be utilized to strengthen other approaches such as the grouping concept (Arts et al, 2015;Oomen et al, 2015). Therefore, the main role BN can have in risk assessment is to rapidly identify those NMs that have the highest human hazard risk ranks and focus these NMs.…”

Regulatory ecotoxicity testing of nanomaterials – proposed modifications of OECD test guidelines based on laboratory experience with silver and titanium dioxide nanoparticles

“…Avoiding animal testing altogether with in silico or in-vitro approaches may also alleviate workload concerns. There is also scientific value in these approaches for grouping and ranking (Oomen et al, 2015) and for efficient concern-driven testing strategies (Oomen et al, 2014). Such modifications are currently not considered in the scope of the OECD test guidelines.…”

Immunotoxicity, genotoxicity and epigenetic toxicity of nanomaterials: New strategies for toxicity testing?

“…Recently, a research strategy was proposed for the development of an intelligent testing strategy for NMs (Stone et al, 2014) based on several steps: identification of the biological mechanism underlying the toxic effect and the physicochemical properties of the NMs that drive the toxic effects; design of in vitro and HTS screening tools that target these key biological processes; development of robust in silico approaches for risk assessment (Oomen et al, 2015;Dekkers et al, 2016). An important aspect of impact assessment of NMs is the grouping and ranking of NMs and NM-containing products according to their inherent toxicity.…”