Persistence Assessment Tool Methodology backed up in journal

Ricardo, member of WSP and a global environmental, engineering and energy consultancy, has announced that its tool for measuring persistent, toxic substances found in many chemicals and chemically derived products – such as plastic – has been peer-reviewed and published in the Integrated Environmental Assessment and Management.

The free-to-access Persistence Assessment Tool (PAT), developed by Ricardo together with Concawe, ICCS (International Collaboration on Cosmetics Safety) and CEFIC-LRI (European Chemical Industry Council, Long-range Research Initiative), allows users to evaluate the degradation half‑life of substances by providing a structured and clear methodology to capture and store information on persistence; evaluate data quality; carry out a robust and transparent weight of evidence determination; and assess persistence in line with the EU REACH regulatory framework, while remaining flexible to accommodate other international regulatory practices.

The PAT tool was first launched in 2023, with an updated version released December 2025. The tool has also been cited in the latest EU Classification, Labelling and Packaging regulation, commonly known as CLP. 

Released in 2023, the model was developed by Ricardo’s in-house chemical team, who applied their over 50 years of expertise in chemical safety and legislation to develop the PAT, to improve the consistency, transparency and robustness of chemical assessments required by global regulations.

The model’s methodology was published in the Integrated Environmental Assessment and Management, a peer-reviewed journal owned by Oxford University with an impact factor of 8, reflecting its standing in the academic world. The article, which received two peer-reviews, demonstrates Ricardo’s PAT model as a reliable source for assessing substances’ persistence in the environment and argue that it should be used as part of a “systematic methodology to collate, evaluate, and integrate relevant information to reach robust, transparent and consistent conclusions for persistence assessments”.

Concerns about the persistence of chemicals – such as per-and poly fluoroalkyl substances (PFAS; "forever chemicals") and Persistent, Mobile, and Toxic (PMT) substances, and even microplastics – and their impact on human and ecological health are of growing concern. With the EU and other jurisdictions introducing regulations to limit the use of these chemicals which can linger in waterways and soil for decades, there is an increasing requirement for tools like PAT.

Simon Gutierrez, Environmental Chemistry and Toxicology Lead for Ricardo, said, “We’re delighted to have our PAT model verified in the Journal of Integrated Environmental Assessment and Management. The article itself comes at a time when the conversation around persistent, 'forever chemicals’, is growing, and we agree there should be a systematic approach to chemical assessment to ensure consistency in response and transparency for communities.”