Environmental behaviors, biotransformation, and toxicological risks of PFPiAs: A comprehensive review of an emerging PFAS

As long-chain per- and polyfluoroalkyl substances (PFASs), such as perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkane sulfonic acids (PFSAs), are gradually phased out due to regulatory restrictions, attention has increasingly shifted to emerging alternatives. Among them, perfluoroalkyl phosphinic acids (PFPiAs) have been commercialized since the 1970s, primarily as wetting agents in consumer products and as components in defoaming agents and pesticide formulations. Despite their long-term use and widespread occurrence in environmental and biological media, comprehensive knowledge of their environmental fate—particularly their transport, transformation, and toxicological impacts—remains limited. Evidence suggests that restrictions on legacy PFASs have altered pollution profiles, and that concentrations of emerging compounds such as GenX may surpass those of conventional PFASs in some contexts. Although currently detected at relatively low concentrations, the continuous production, environmental persistence, and bioactivity potential of PFPiAs indicate a need for closer scrutiny. Given their increasing role as possible replacements for regulated PFASs, a thorough assessment of PFPiAs is critical for informed risk management. This review compiles and synthesizes current research on PFPiAs, focusing on their physicochemical characteristics, environmental and biological behaviors, and toxicological effects, to support future scientific evaluation and regulatory development. Synopsis: This review systematically examines the physicochemical characteristics, environmental behavior, and toxicological implications of PFPiAs, aiming to advance scientific understanding and support evidence-based regulatory frameworks.