Terminology and Classification of Per- and Poly-Fluoroalkyl Substances (PFAS)

doi:10.1515/ci-2025-0116

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Terminology and Classification of Per- and Poly-Fluoroalkyl Substances (PFAS)

Published/Copyright: January 20, 2025

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From the journal Chemistry International Volume 47 Issue 1

Per- and poly-fluoroalkyl substances (PFAS) have become an issue of global concern. PFAS are a large and diverse set of compounds with a wide variety of physical, chemical, and toxicological properties. Some PFAS are persistent, bioaccumulate, and are highly toxic, others are not. Many commercially important agrochemicals, pharmaceuticals, polymers, and chlorofluorocarbon (CFC) replacements are PFAS. The European Commission is considering a proposal to ban all PFAS which has led to concerns being raised by industry. Several definitions of PFAS are in use. The European Chemical Agency (ECHA) defines PFAS as “substances containing at least one aliphatic CF2 or CF3 element.” The U.S. Environmental Protection Agency defines PFAS as “per- and polyfluorinated substances that structurally contain the unit R–(CF2)–C(F)(R1)R2. Both the CF2 and CF moieties are saturated carbons and none of the R groups (R, R1, or R2) can be hydrogen.”

Different definitions of PFAS lead to confusion in technical, regulatory, and public discussions. For example, it has been shown that trifluoroacetic acid (CF3C(O)OH) is a potential degradation product of many agrochemicals, pharmaceuticals, polymers, and CFC replacements. This leads to the question of do these chemicals degrade to give PFAS? Using ECHA definition the answer is “yes,” while using the U.S. EPA definition the answer is “no.” IUPAC has initiated a project to collect, and critically analyze existing information, providing a rigorous definition for PFAS, and standardizing terminology, classification, and nomenclature. The outcomes will benefit the global scientific, regulatory, and industrial communities, by means of a common terminology and a harmonized communication on PFAS. It will align with the IUPAC mission of providing a common language for chemistry and promoting free exchange of scientific information. These findings are expected to help national and global regulation and policy decisions, by filling information gaps and allowing targeted education campaigns.

Is trifluoroacetic acid a PFAS? (Structure from PUBCHEM)

For more information and comment, contact Task Group Chair T. J. Wallington <twalling@umich.edu> or P. Metrangolo <pierangelo.metrangolo@polimi.it> | https://iupac.org/project/2024-006-3-100/

Published Online: 2025-01-20

Published in Print: 2025-01-01

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