Beyond the foam: The overlooked PFAS pathway from textiles, landfills, and wastewater treatment plants to drinking water

PFOS contamination in U.S. drinking water has been predominantly attributed to aqueous film-forming foam (AFFF) releases, but process-level evidence indicates that electrochemical fluorination (ECF)-derived textile chemistry, entering water supplies through municipal landfills and wastewater treatment plants (WWTPs), is an underexamined contributor. EPA’s UCMR 5 dataset shows 12% of large public water systems exceed the 4 ppt PFOS maximum contaminant level, yet current attribution frameworks focus disproportionately on AFFF. This perspective makes a claim about pathway plausibility and process-level evidence, not quantitative source attribution. The evidence demonstrates that: (1) ECF-based stain-resistant textile treatments applied to consumer products for decades represent a PFAS source pathway independent of firefighting foam; (2) municipal landfills containing ECF-treated textiles generate PFOS through precursor transformation, with leachate ∑PFAS of 3,200–96,000 ng/L and comparable primary and secondary leachate concentrations at studied facilities; (3) WWTP biological treatment converts sulfonamide precursors to terminal PFOS, with post-treatment increases up to 1,335% at studied facilities; and (4) the pathway operates at national scale, with over 60% of PFAS mass from carpets and cosmetics accumulating in landfills. A preliminary mass balance places cumulative textile/consumer-product fluorochemistry within the same order of magnitude as cumulative AFFF fluorochemistry. Five research gaps are identified, and existing EPA infrastructure (Method 1633 A, Method 1621) provides the technical foundation. Mixed-source scenarios are likely the norm; apportionment that defaults to the most familiar pathway risks technical inaccuracy and misallocated remediation investment.