JCR, RIVM, BfR and BASF directly involved, with Echa on advisory board
An EU project involving Echa in an advisory capacity has developed a framework for grouping nanomaterials that is designed to be compatible with REACH, in addition to established safe-by-design processes.
In 2018, the EU made changes to the REACH annexes to increase the amount of nanomaterials data in registration dossiers, with the aim of ensuring that the data was sufficient to demonstrate safe use of all nanoforms covered. The new requirements came into force on 1 January.
While Echa has published REACH guidance on nanomaterials risk assessment – and on grouping and read-across – one of the developers of the framework said new tools are needed to bridge the gap between what this guidance says and the specific challenges facing registrants.
One of the framework’s aims is to reduce the administrative burden on companies required to submit nanomaterials data under REACH by facilitating read-across. Echa says it offers a “valuable scientific contribution” to the discussion on grouping and read-across for nanoforms, but alone would not be sufficient for constructing a dossier for nanomaterials.
The framework, which is described in a paper published in Nano Today on 8 August, is an output of the GRACIOUS project, which the EU launched in 2018 and will run until 30 June 2021.
The 22 authors of the paper include scientists at various organisations, including:
the European Commission’s Joint Research Centre (JRC);
the Dutch National Institute for Public Health and the Environment (RIVM);
the German Federal Institute for Risk Assessment (BfR); and
chemical company BASF.
The first named and corresponding author is Vicki Stone at Heriot-Watt University in Edinburgh.
The framework is built around a set of grouping hypotheses, each of which comprises one or more statements about toxicology and physicochemical properties.
For example, one hypothesis is that “non-flexible nanoforms of more than 5 nm in length … following dermal application will not penetrate (in their particle form) to viable layers of the skin above 1% of the applied dose”.
In the first step, users collect basic information about a nanomaterial, which guides selection of a hypothesis. They then test whether or not the hypothesis applies using the integrated approaches to testing and assessment (Iata) concept, which is supported by the OECD.
Iata describes how test data from multiple sources can be combined in an iterative way to answer a specific scientific question about hazard.
If the available data supports the hypothesis, with sufficient certainty for the particular decision context, read-across from similar nanomaterials to fill data gaps may be possible.
‘Scope for interpretation’
Professor Stone says that Echa guidance does not specify the “exact methods” that should be used to make read-across predictions, “so there’s lots of scope for interpretation within that guidance”.
Furthermore, the frameworks previously developed by scientists have been limited in scope by, for example, focusing on just one route of exposure.
The GRACIOUS framework builds on these, with a scope that includes “all relevant exposure routes for humans and all compartments in the environment”.
The project is developing a software application based on the framework and the aim is to share that with stakeholders for feedback by the end of the year.
Professor Stone says that the framework should be sustainable beyond the end of the project because developers of other risk-assessment and decision-support software are free to integrate it into their products and update the content as needed.
However, further work will be needed on the test methods for generating the required data.
“There will be varying levels of confidence in some of the answers,” she says. “What we’ll do is identify where there’s less confidence and that will help people to identify the method development that’s required in future.”
Chemical Watch, 20 August 2020