This study represents recent efforts by the OECD/UNEP Global PFC Group between
January 2017 and February 2018 in updating the OECD “Lists of PFOS, PFAS, PFOA,
PFCA, Related Compounds and Chemicals That May Degrade to PFCA”, which was last
updated in 2007, to provide a comprehensive list of per- and polyfluoroalkyl substances
(PFASs) that may have been on the global market. In particular, it focuses on those
PFASs, including perfluorocarbons, that contain a perfluoroalkyl moiety with three or
more carbons (i.e. –CnF2n–, n ≥ 3) or a perfluoroalkylether moiety with two or more
carbons (i.e. –CnF2nOCmF2m−, n and m ≥ 1). The study utilises publicly accessible
information sources, including (1) two lists of PFASs (and other highly fluorinated
substances) by national or international regulatory bodies, (2) nine public
national/regional inventories of chemicals, (3) two public national/regional inventories of
chemicals in specific uses, (4) four public national/regional inventories of chemicals
subject to specific regulations, and (5) one scientific database.
In total, 4730 PFAS-related CAS numbers have been identified and manually categorised
in this study, including several new groups of PFASs that fulfil the common definition of
PFASs (i.e. they contain at least one perfluoroalkyl moiety) but have not yet been
commonly regarded as PFASs. The identified PFASs are diverse in terms of structure and
other categorisation elements. In addition, the number and type of identified PFASs vary
considerably across sources. Several limitations, gaps and challenges were identified,
including (1) information gaps within the information sources searched, (2) gaps
associated with information sources that were included, (3) limitations associated with the
format of the study (as a snap shot of the situation when the study was done, while
information may continuously evolve), and (4) challenges associated with the vague
description of some PFASs identified, the currently used terminology of PFASs, and the
current state of knowledge about certain aspects such as the degradability of many
PFASs. As such, it should be noted that while this list is comprehensive, it is not an
exhaustive list.
Based on lessons learned from identified limitations, gaps and challenges, opportunities
for future improvement have also been identified. In particular, there is a need for an
intensified dialogue and cooperative actions across regions and sectors, designing and
fostering new types of public-private partnerships to facilitate effective and efficient
information exchange between public and private sectors within the field of PFASs.
Additional recommendations include (1) expansion of the current terminology of PFASs
to reflect all substances and resolve issues identified (e.g., no clear cut-off values between
some substance groups), (2) development of a web-based knowledge base to share up-todate information on PFASs across sectors and regions, and (3) continuous support to
address critical knowledge gaps including the degradability of many non-studied PFASs.
