Hydra's scenes of per- and polyfluoroalkyl substances (PFAS): Occurrence and removal across environments

and polyfluoroalkyl substances (PFAS) have been widely utilized across various industrial and consumer applications due to their exceptional chemical and thermal stability, as well as combined hydrophobic-oleophobic properties. Representative applications include non-stick cookware coatings, water-repellent textile agents, industrial lubricants, and high-temperature sealing materials. Despite their functional advantages, the extreme environmental persistence of PFAS has raised growing concerns regarding their adverse impacts on ecosystems and human health. Owing to strong C–F bonds, PFAS exhibit extreme resistance to degradation, environmental persistence, and bio accumulative potential, leading to widespread ecological consequences.Human exposure to PFAS is associated with multiple health risks, including immunosuppression, endocrine disruption, hepatotoxicity, nephrotoxicity, and increased cancer risk, primarily through the ingestion of contaminated water and food. Current removal strategies mainly include adsorption, chemical degradation, membrane separation, and microbial degradation.However, these approaches often face significant challenges under real-world environmental conditions due to the complexity of environmental matrices. Natural aquatic systems typically contain a variety of coexisting constituents, such as inorganic salts, heavy metals, and natural organic matter, which compete for adsorption sites or interfere with degradation pathways, thereby reducing PFAS removal efficiency. Although numerous laboratory-scale studies have demonstrated high removal efficiencies, their applicability to complex environmental settings remains uncertain. Hence, tailoring PFAS removal strategies to specific environmental contexts is imperative. In situ evaluation of both removal mechanisms and environmental variables will be critical for identifying optimal remediation pathways. This review comprehensively examines the major sources, environmental distribution, and potential risks of PFAS.It focuses on comparative analysis of removal technologies and underlying mechanisms under various environmental conditions, with particular emphasis on the impact of environmental factors on PFAS removal efficiency.Furthermore, the review explores strategies to leverage these environmental variables to optimize remediation processes, thereby achieving more efficient and sustainable PFAS remediation. • This review focuses on the effects of specific factors (ionic species, intensity, organic matter) in different scenarios (marine, industrial wastewater, agricultural water) on the removal and degradation mechanisms of PFAS. • This review not only provides precise guidance for the technical selection in specific scenarios (e.g., in waters with high cation concentrations, the adsorption method can be more efficient), but also promotes the research to evolve from "generalization" to "scenario customization". • This review comprehensively examines the sources, occurrence, and risks of prevalent PFAS, as well as their removal techniques and mechanisms under diverse environmental conditions. • Particular emphasis is placed on the influence of environmental factors on PFAS