Laundry fibers as vectors for PFAS in U.S. wastewater treatment: Challenges and policy considerations

Per- and polyfluoroalkyl substances (PFAS) represent persistent environmental contaminants of increasing regulatory concern, yet pathways for their transport through urban water systems remain incompletely characterized. This study investigates the role of laundry-derived textile fibers as vectors for PFAS in U.S. wastewater treatment systems. Analysis of literature from some geographically diverse wastewater treatment plants revealed substantial quantities of synthetic fibers (8,200-27,400 fibers/L) in influent, with 87.3% of analyzed fibers containing detectable PFAS concentrations (0.8-34.7 ng/g fiber). Polyester fibers demonstrated the highest PFAS affinity, with concentrations positively correlated with fiber hydrophobicity and surface weathering. Treatment efficacy varied significantly across technologies, with conventional activated sludge processes removing 74.2% of fibers but only 42.1% of fiber-bound PFAS mass, while membrane bioreactor systems achieved 96.3% fiber removal and 67.8% PFAS removal. Mass balance calculations indicated 53-72% of removed fiber-bound PFAS accumulated in biosolids, with the remainder partitioning to the dissolved phase or undergoing transformation. Effluent analysis confirmed breakthrough of both fibers (320-1,450 fibers/L) and fiber-associated PFAS to receiving waters, representing 14-27% of total PFAS discharge from studied facilities. Regional variations in fiber characteristics and PFAS loading reflected socioeconomic patterns in textile consumption. These findings identify laundry fibers as a significant and previously under quantified vector for PFAS transport through wastewater systems, with implications for treatment design, biosolids management, and regulatory frameworks. Current U.S. policies inadequately address this pathway, highlighting the need for coordinated interventions spanning textile manufacturing, wastewater treatment technologies, and biosolids application practices.