Per- and polyfluoroalkyl substances in fish: A review of bioaccumulation, trophic transfer, and environmental health risks

• Synthesizes PFAS bioaccumulation across marine and freshwater fish globally • PFOS dominates fish tissues with levels up to 3900 ng/g (liver) • Liver shows a higher PFAS burden due to protein-binding behavior • Freshwater fish often exhibit higher PFAS than marine species • Fish intake may reach PFOS exposure of 29.5 ng/kg/day Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants widely detected in freshwater and marine ecosystems, where they accumulate in aquatic organisms and may pose ecological and human health risks. This review provides a mechanism-oriented synthesis of PFAS occurrence, internal accumulation processes, and trophic transfer in fish across diverse aquatic environments. Rather than relying solely on concentration-based summaries, this study integrates physicochemical properties, protein-binding behavior, organismal physiology, and environmental drivers to explain variability in reported PFAS burdens. Compiled data reveal substantial variability in PFAS concentrations among species, tissues, and geographic regions, reflecting both environmental heterogeneity and methodological differences in analytical approaches and reporting bases. Among individual compounds, perfluorooctane sulfonate (PFOS) consistently emerges as a dominant PFAS, likely due to its historical production, environmental persistence, and strong affinity for protein-rich tissues. The highest reported concentration was observed in fish liver from Lake Halmsjön, Sweden (3900 ± 500 ng/g wet weight). Tissue-specific accumulation patterns, particularly elevated concentrations in metabolically active organs, are primarily governed by protein-binding interactions rather than lipid partitioning. While higher PFAS levels in fish are generally associated with elevated aqueous concentrations, this relationship reflects environmentally mediated exposure rather than definitive trophic magnification. Moreover, inconsistent relationships between fish morphometrics and contaminant burdens can be explained by competing physiological processes, including cumulative exposure and growth dilution. From a human health perspective, fish consumption represents a relevant exposure pathway for certain PFAS; however, risk characterization remains sensitive to assumptions regarding dietary intake, tissue selection, and regulatory benchmarks. Future research should prioritize standardized trophic metrics, harmonized reporting practices, improved analytical coverage of emerging PFAS, and integration of physiological and environmental drivers to strengthen ecological and human health risk assessments.