Quaternary Ammonium Compounds (QACs) in Textiles and Laundry Wastewater: Occurrence and Environmental Risk Assessment

Quaternary ammonium compounds (QACs) have been used as antimicrobial additives in textiles, but information on their levels in textiles and ecological impacts from laundry wastewater is scarce. Here, 119 textile products from Chinese online vendors were analyzed for traditional and emerging QACs using target and suspect screening approaches with high-resolution mass spectrometry. The total concentrations of 18 traditional QACs ranged from 7.34 to 145,000 ng/g, and 16 emerging QACs were identified with total concentrations at 5.45 to 349,000 ng/g. Under laboratory-controlled conditions, over 76% of the selected textiles exhibited QAC migration rates exceeding 50% after washing. In simulated laundry experiments, hand-washing released a ΣQAC concentration of 42.1 ng/mL, and machine-washing released 22.4 ng/mL, with differences attributed to the water volume used by different methods. Both laundry wastewater and QACs solution at equivalent concentrations caused dose-dependent immobilization of <i>Daphnia magna</i>. Combining bioassay-based risk characterization factors with environmental dilution factors across 150 countries, 7% of regions showed high risk after WWTP-treatment, increasing to 41% for direct discharge with sewage. The high migration rates suggest that QAC-treated textiles not only fail to maintain long-term antimicrobial efficacy but also contribute to continuous low-level environmental exposures, raising concerns about their essential use in nondisposable textile materials.