Per and Polyfluoroalkyl Substances (PFAS) are a family of thousands of chemicals widely used in industrial and consumer applications since the 1950s, most often where extremely low surface energy or surface tension and/or durable water and oil repellency is needed (e.g. in various fire-fighting foams and for surface treatment of textiles). Some PFASs have been produced and used on a scale of thousands of tonnes or greater annually. Numerous efforts have been made to assess the risks associated with PFASs, with a focus on so-called “long-chain” perfluoroalkyl acids. Consequently, long-chain PFASs have been widely recognized as contaminants of high global concern due to their high persistence, bioaccumulation potential, toxicity, and ubiquitous distribution in the global environment, biota and humans (GCO II, UNEP 2019).
The OECD maintains a global database of PFASs. To date, more than 4,700 Chemical Abstracts Service (CAS) numbers have been identified which can be associated with a large variety of PFASs that may have been on the global market and in the environment. Meanwhile, a complete account is still lacking due to an absence of transparent, quantitative information on the production and use of PFASs, and lack of analytical standards in the public domain.
While substantial progress has been made in understanding the hazards, exposure, risks and treatment of some long-chain PFASs, other PFASs and non-fluorinated alternatives have received limited attention. Information on the hazards of many non-fluorinated alternatives to PFASs is lacking; hence scientists, regulators and civil society organizations are increasingly calling for effective and efficient assessment and management of overlooked and novel PFASs and for research on non-fluorinated alternatives to PFASs (GCO II, UNEP 2019). Recent studies suggest that many overlooked and novel PFASs possess some of the same properties as structurally similar long-chain PFASs, including toxicity, high persistence, mobility in the environment and modes of action (Scheringer et al. 2014; Birnbaum and Grandjean 2015; Blum et al. 2015; Wang et al. 2015; Wang et al. 2016; Gomis et al. 2018). In addition, recent studies show that many PFASs, particularly those with short perfluoroalkyl(ether) chains, cannot be removed from contaminated water by using conventional and many advanced treatment technologies
Widespread efforts have been made to phase out and replace long-chain PFASs with alternatives. In 2009, at the second session of the ICCM, “Perfluorinated chemicals and the transition to safer alternatives” was recognized as an issue of concern under SAICM.