Risks associated with PFAS in the environment and consumer products: from sources and exposure pathways to monitoring and mitigation

Abstract

Per- and polyfluoroalkyl substances (PFAS) are synthetic chemical compounds used widely in industrial and consumer products. The exceptional stability of terminal perfluoroalkyl acids (PFAAs)—including perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS)—stems from strong carbon–fluorine bonds, which render these compounds highly resistant to environmental degradation. Polyfluoroalkyl precursors, by contrast, retain at least one non-fluorinated carbon and are capable of undergoing stepwise environmental transformation, ultimately yielding the same persistent PFAAs as terminal products. This longevity has led to widespread contamination of surface waters, groundwater, soils, and drinking water globally. In 2024, the U.S. EPA established enforceable standards for six PFAS, with limits as low as 4 ng/L for PFOA and PFOS, reflecting health concerns at trace concentrations. Legacy compounds continue to persist despite regulatory phase-outs. Short-chain alternatives and polyfluoroalkyl precursors transform into stable perfluoroalkyl acids, sustaining environmental burdens. We examine PFAS chemistry, environmental fate, and management technologies across the product life cycle-from manufacturing to disposal. Transport through interconnected environmental compartments receives particular attention, with soils and sediments functioning as long-term secondary sources. Toxicity in aquatic organisms and human health implications are reviewed, with emphasis on chronic low-dose exposure and mixture effects. Analytical approaches span targeted methods, suspect screening, and fluorine mass-balance techniques. Management technologies are evaluated with a distinction between separation and destruction processes, including verification requirements. Knowledge gaps in emerging PFAS, precursor transformation, and analytical harmonization point toward the need for improved monitoring and risk-reduction strategies. Key conclusions of this synthesis are: (a) soils and sediments act as long-term PFAS reservoirs introducing multi-year lags between emission controls and exposure reductions; (b) targeted analytical methods capture only a fraction of total organofluorine burden, requiring tiered frameworks combining TOP assay and fluorine mass-balance metrics; (c) human exposure is inherently mixture-driven and demands compound-group rather than substance-by-substance risk assessment; and (d) treatment technologies must demonstrate verified destruction rather than mere phase transfer of PFAS.