Chemical persistence plays a key role in the determination of environmental exposure making it an important component in risk assessment and regulation. Interest in chemical persistence has increased significantly, highlighted by concerns from per- and polyfluoroalkyl substances (PFAS), (micro)plastic pollution and persistent, mobile and toxic (PMT) substances.
Persistence assessment in the regulatory context involves comparing chemical degradation half-lives to set criteria for different environmental compartments (water, sediment and soil). Other information is also relevant for assessments (e.g. biodegradation screening tests, non-standard experiments, QSARs, field data, etc), and should be considered following a ‘weight-of-evidence’ approach. Implementation challenges remain in persistence assessments, particularly relating to guidance around the evaluation of data quality, and the weight-of-evidence determination. In addition, there are issues for substances whose properties render them difficult to evaluate using standard methods.
This project, sponsored by Concawe, Cosmetics Europe and Cefic-LRI, aims to develop a Persistence Assessment Tool (PAT) to support the evaluation of persistence under regulatory frameworks such as EU REACH. This software tool will provide clear guidance and structure to evaluate data quality, and a quantitative weight-of-evidence (qWoE) methodology to process the information input and calculate persistence conclusions. It will provide specific features to account for difficult and complex substances. The qWoE methodology will allow users to adapt assessments to specific regulatory frameworks and other purposes. A further feature will be to incorporate a multimedia fate model to allow for the determination of overall persistence.
The aim of the PAT is to provide support to practitioners responsible for undertaking persistence assessments, and to facilitate improved consistency, transparency and robustness in these assessments. This presentation will provide an overview of the tool under development, the challenges it seeks to address, and information on how interested stakeholders can participate in the development of the tool.