Assessment of substance Persistence, Bioaccumulation and Toxicity (PBT) properties is required under different regulations, for industrial chemicals (REACH), veterinary medicines, plant protection products and biocides.

The evaluation of PBT/vPvB properties requires the use of all available screening and assessment information available for a substance, which is then considered using a weight of evidence approach. This means that all relevant data from in vitro tests, data from human and animal studies, QSAR and read across, and monitoring and modelling studies should be included. The quality and consistency of the data are given appropriate weight and then considered together in a single weight of evidence determination.

wca have conducted PBT assessments for a range of substances including chemical substances of Unknown or Variable Composition, Complex Reaction Products and Biological Materials (UVCBs), and are experienced in responding to questions from ECHA on this topic. Our scientists have also influenced the recent updates to the PBT/vPvB guidelines and the weight of evidence approach by contributing to key recent publications on this topic. For further information, see our blogs on the PBT weight of evidence approach and terrestrial bioaccumulation.

Our services include:

• Determination of the relevant compartment of concern for a substance
• Data gap assessment.
• Proposal of testing strategies following the general approach of concluding on “P”, then “B” and finally on PBT / vPvB.
• Commissioning of relevant testing, study monitoring and interpretation of the results in the context of PBT assessment.
• Weight of evidence assessment for PBT properties.

For further information on our PBT and vPvB assessment capabilities, please contact us.