ECHA and the EU Member State competent authorities are conducting screenings of the registered substances to find potential PBT or vPvB substances. Authorities also carry out preparatory assessments of selected substances mainly originating from the screenings to clarify which of the formal decision processes under the REACH Regulation described above is appropriate and necessary to clarify the concern, if any. Voluntary engagement of registrants is also considered as an option. ECHA's PBT Expert Group provides an informal forum for discussing and coordinating the activities related to the search and assessment of suspected PBT/vPvB substances.
The PBT/vPvB assessment is a challenging task as it generally contains an assessment of four fate/hazard endpoints (persistence, bioaccumulation, ecotoxicity and toxicity). Furthermore, most substances that are likely to fulfil the PBT/vPvB criteria have such physical-chemical properties that they are very difficult to test and to assess.
Standard information in the registration dossiers may not be sufficient for concluding the assessment and additional standard or non-standard testing, or other studies may need to be tailored to answer the specific needs case-by-case. The assessors (authorities, registrants) are often confronted with complex questions regarding how to conduct the PBT/vPvB assessment or how to test the substance in the most efficient manner. Therefore, best practices of assessment need to be developed further. An optimal preparation is, before initiating any of the formal decision processes under the REACH Regulation, to clarify the suspected PBT/vPvB concern in line with the guidance and to seek advice from relevant experts. The PBT Expert Group serves these needs for provision of informal scientific advice to authorities and ECHA.