Future Perspectives on Registration of Polymers in Europe

Background:The exemption of polymers of low concern (PLC) has been a global trend in chemical registration.EU REACH already requires the registration of monomers, but is moving toward registering polymers based on their unique hazards.Objectives: Criteria for polymers requiring registration (PRRs) as well as their groupings and read-across approaches are presented with a case example for upcoming polymer registration in REACH. Methods:The definition of polymers and PLC criteria were reviewed in the history of polymer regulations in the EU and USA based on documents from the US EPA, OECD and ECHA as well as EU Directives/ Regulation.PRR criteria were reviewed from technical reports prepared by the European Committee and documents of CASG-Polymers (CARACAL Subgroup on Polymers).Grouping approaches for PRR with a case study were summarized from technical reports prepared by the ECETOC (European Centre for Ecotoxicology and Toxicology of Chemicals). Results:As first defined in the 1984 polymer exemption rule in the US Toxic Substances Control Act, the definition of polymer features the "3n+1" rule and the "50%" rule.PRR criteria originated from the opposite concept of PLC have been suggested by the European Committee and updated by CASG-polymers, resulting in criteria including molecular weight, cationicity, surface-active properties, reactive functional groups, hazard classification, fluorination and degradation to substances of concern.Notification of polymer status such as precursor, non-PRR or PRR will be followed by PRR registration with grouping approaches.According to the ECETOC's case study on alcohol ethoxylates (AEs), a hazard-similarity approach is suitable for subgroup AEs where a read-across approach can be applied among group members.The key parameter is the hydrophilic/hydrophobic balances of AE's C-chain length and degree of ethoxylation.Conclusions: EU REACH is planning to implement PRR registration.The main strategy is on grouping polymers based on hazard similarities, registering each subgroup of polymers as a single substance, and obtaining hazard data for group members by applying read-across approaches.