LRI ECO70: Expanding the applicability domain of the OECD test guideline 309 for biodegradation simulation testing to address difficult-to-test properties

Description

This proposed project aims to identify, optimise, and validate non-guideline adaptations to enhance the reliability, applicability, and regulatory acceptance of OECD 309 for the assessment of the persistence of substances that are: poorly water soluble, volatile, hydrophobic, or of complex composition, e.g. Multi-Constituent Substances (MCSs) and substances of unknown or variable composition, complex reaction products or of biological material (UVCBs). Specifically, the project will: 

• Conduct a comprehensive review of relevant academic literature, guidance documents, and TGs to establish an up-to-date evidence base on the issues and opportunities associated with both guideline and non-guideline approaches to testing of difficult and complex substances (WP1).
• Establish a comprehensive set of evaluation metrics for assessing the performance, validity, and comparability of unmodified and modified test setups (WP2).
• Quantitatively or qualitatively define the applicability domain of the current TG in terms of complex composition, solubility, volatility, hydrophobicity, and combinations thereof, assessing the applicability of each to the unmodified TG 309 (WP3).
• Compile and critically assess existing and emerging dosing strategies and test system adaptations, including through consultation with the Fraunhofer-DTU project team (WP4).
• Experimentally optimise and validate a selection of these methods in two laboratories, using a representative range of difficult-to-test substances (WP5).
• Consolidate findings into a final report and two peer-reviewed publication, with dissemination of results and recommendations at relevant scientific conferences (WP6).

The project outcome will support the improvement of the TG and/or development of guidance for the accurate and standardised surface water biodegradation testing of a wide range of substance types, aligning with the work of other recent and ongoing projects aiming to improve the OECD TG 309 (e.g. ECO55) and biodegradation simulation testing guidance for difficult and/or complex substances (e.g. ECO52, ECO64, ECHA Fraunhofer/DTU project).