Per- and polyfluoroalkyl substances (PFAS) are a group comprised of thousands of diverse chemical structures. According to the Organisation for Economic Cooperation and Development (OECD), “to date, research has primarily focused on understanding the identity, life cycle, hazard, occurrence and exposure, and risk of non-polymeric PFASs…To ensure the sound management of the entire class of PFASs, it is equally important to understand polymeric PFASs.” Polymeric PFAS are polymers (e.g., plastics and silicones) with components of their chemical structure that meet the OECD PFAS definition. This group of substances are called side-chain fluorinated polymers (SCFPs).
In December 2022, the OECD published a report summarizing the publicly available information on SCFPs. Due to the growing attention towards regulating PFAS around the world, there is some discussion over whether SCFPs should be excluded from recent and proposed blanket PFAS bans. Bringing evidence to the debate, the OECD found that many non-polymer PFAS, which would likely be included in any ban, are present in SCFPs. The report authors stated, “it is well expected that SCFPs can degrade and form non-polymeric PFAS… Thus, many SCFPs are acting as long-term significant sources to the global burden of non-polymeric PFAS.”
The report inventories over 100 SCFPs and 42 monomers of interest that have been on the global market. The substances are divided into four groups based on their chemical structure: acrylates and urethanes; oxetanes; silicones; and ethoxylates. Each group gets a dedicated chapter that includes “production and use of respective SCFPs, presence of other PFASs in the commercial formulations, degradation of SCFPs during use and end-of-life treatment, environmental releases of SCFPs, and other PFASs present in the commercial formulations, [and] a summary of critical knowledge gaps and options for a way forward.”
The report concludes that “in parallel to action on critical knowledge and data gaps, concerted action may be taken to develop, facilitate and promote national and international stewardship programmes and regulatory approaches to reduce emissions of SCFPs and related PFASs and to work toward global elimination, where appropriate and technically feasible.”
In August 2022, researchers concluded that “PFAS define a new planetary boundary that has been exceeded,” based on the substances’ ubiquity, difficult removal, and disruption to vital Earth systems (FPF reported). In January 2023, five European nations submitted a proposal to the European Chemicals Agency to restrict all PFAS in the EU (FPF reported). The Food Packaging Forum’s dashboard on migrating and extractable food contact chemicals (FCCmigex) includes a button to filter results to only the PFAS studied in food contact materials.
References
OECD (2022). “Synthesis report on understanding side-chain fluorinated
polymers and their life cycle.” (pdf)
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