Colloidal Side-Chain Fluorinated Polymer Nanoparticles Are a Significant Source of Polyfluoroalkyl Substance Contamination in Textile Wastewater

Abstract

Side-chain fluorinated polymers (SCFP) are a class of per- and polyfluoroalkyl substances (PFAS) that are extensively used in functional textiles as water and stain repellents. The potential for environmental contamination through the release of SCFP into aqueous waste streams during textile manufacturing is poorly understood. In this study, SCFP in textile wastewater were characterized using targeted analysis, total oxidizable precursor (TOP) and total hydrolyzable precursor (THP) assays, ultrafiltration, and asymmetric-flow field-flow fractionation (AF4). An investigation into point sources of PFAS precursors in Burlington, NC’s wastewater treatment plant (EBWWTP) using the TOP assay revealed a significant PFAS burden stemming from textile manufacturing operations within the city’s sewershed (max: 12,000,000 ng/L after oxidation), far outweighing domestic contributions. TOP and THP profiling of textile manufacturing wastewater showed that the dominant precursors contained 6:2 fluorotelomer functionality, and ultrafiltration and AF4 showed them to be colloidal in size (hydrodynamic diameter: ∼100 nm), resulting in the determination of SCFP in textile wastewater. PFAS mass loading analysis showed that most SCFP exiting the EBWWTP were associated with sludge rather than effluent, where ∑PFAS concentrations up to 150,000 ng/g were measured using the direct TOP assay; thus, the land application of SCFP-contaminated biosolids may represent a significant route of environmental contamination.