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Consider Read across and grouping approaches

Read across and grouping approaches (chemical categories) can be very helpful when collecting and evaluating data also in a Weight of Evidence approach. Read across and chemical categories rely on the fact that the substances physicochemical, toxicological and ecotoxicological properties are likely to be similar or follow a regular pattern as a result of structural similarity. Data on analogous substances, if 'read across' or membership of a 'chemical category' is possible, should also be considered by contacting SIEFs with related substances.

A valuable tool to consider when building categories or considering read across is the OECD QSAR Toolbox. It facilitates the practical application of grouping and read across approaches for data gap filling. The Toolbox incorporates information and tools from various sources (including a link to the eChemPortal) into a logical workflow and also allows the prediction of a number of properties related to (eco)toxicological properties. The Toolbox software is available for download free of charge along with additional information materials and guidance for installation and use.

A public discussion forum for users of the QSAR Toolbox is also available and users can:

• Exchange experience on using the software (tips and tricks)
• Seek guidance
• Exchange databases
• Exchange user defined profilers and QSARs
• Make suggestions for improvements

Consider QSAR analyses/estimations

The collection of all available information should include the search for suitable QSAR models. QSAR predictions are assessed for adequacy and if appropriate they can be considered for risk assessment and/or classification and labelling. (Q)SAR models are non-test methods that can assist on data generation but also on data interpretation.

The international activities on (Q)SARs are coordinated by the OECD.

The Institute for Health and Consumer Protection (IHCP), a scientific institute of the European Commission's Joint Research Centre (JRC), provides additional resources with respect to QSAR tools and their use for regulatory purposes. Users of QSAR models are advised to look at these resources and use them when relevant.

Harmonised templates for summarising and reporting key information on QSAR models, QSAR model reporting formats as well access to the QSAR model database are available on the IHCP website.

Additional important information sources that relate to the QSAR models are also available on the IHCP website.
 

Assessment of information

All available information (existing data on the substance, similar substances or derived with the use of non-test methods (QSAR, read across and grouping)) should be assessed for validity and adequacy. Consider the information in a Weight of Evidence approach in order to make decisions on the need for additional information. The resources and tools used in order to gather information could also be used to decide which tests are the most appropriate for data gap filling.

When deciding what type of test is needed to fulfil REACH information requirements, in vitro tests and non-test data should be considered first in order to avoid unnecessary animal testing.
 

In vitro methods

Data generated from in vitro test methods (validated and pre-validated) can be used under REACH provided that the information for the hazard endpoint is sufficient for the purpose of classification and labelling and/or risk assessment. Such information can be used either as stand-alone to fill in a data gap or as part of a Weight of Evidence approach.

The European Centre for Validation of Alternative Methods (ECVAM) provides a database on alternatives to animal testing which has useful information on in vitro methods that could be considered during information gap analysis for REACH registration purposes. The database contains information on methods that are in use or under development as well as those validated and/or accepted for regulatory purposes.

In addition, tracking system for alternative test methods review (TSAR) is another source of information to be considered when deciding whether in vitro tests could provide the information needed for data gap filling or in a Weight of Evidence approach.
 

Additional resources

The following links provide access to products developed by the OECD and WHO for risk assessment purposes.

• OECD Environmental Risk Assessment Toolkit: Gives access to practical tools on environmental risk assessment and management of chemicals. It describes the work flow of environmental risk assessment and management with links to relevant OECD products that can be used in each step of the work flow.
• WHO Human Health Risk Assessment Toolkit: Aims to make the international tools available on chemical risk assessment more readily accessible in the form of a "toolkit" and develops related training materials including case study examples of use of the tools.