Per- and Polyfluoroalkyl Substances (PFAS) in aquatic sediments: Partitioning behavior, ecological consequences and policy gaps

Per- and polyfluoroalkyl substances (PFAS) are persistent organic pollutants, accumulate across aquatic compartments, including sediments, pore water, surface water, and suspended particle matter (SPM), causing long-term ecological impacts. This review analyzes PFAS partitioning behavior across these media, emphasizing the roles of molecular structure, functional groups, and site-specific conditions. SPM consistently retains higher PFAS levels than sediments, while porewater concentrations exceed those of surface water, revealing overlooked exposure pathways. Sediment-bound PFAS expose benthic organisms through dermal contact, ingestion, and trophic transfer, with bioaccumulation influenced by organism traits, sediment properties and environmental factors. Although ecological risk quotient (RQ) values are generally low, localized hotspots and species-specific sensitivities highlight the need for site-specific monitoring. Regulatory frameworks in the EU and US remain focused on drinking and surface waters, lacking sediment-specific standards and leaving a critical policy gap. This review also evaluates emerging remediation strategies, underscoring the need for scalable field-deployable technologies, ecotoxicological studies, and regulatory thresholds to mitigate persistent PFAS exposure and protect aquatic ecosystems.