Mobile Short- and Ultrashort-chain PFAS in Korean Aquatic Systems: Matrix-specific Profiles, Industrial Signatures, and Sum-based Monitoring Implications.

This study investigated the occurrence and compositional characteristics of short- and ultrashort-chain per- and polyfluoroalkyl substances (PFAS) across tap water, surface water, and wastewater in South Korea. Targeted quantification of 11 PFAS was combined with high-resolution mass spectrometry (HRMS)-based suspect screening to evaluate matrix-specific profiles and monitoring implications. A total of 36 water samples were analyzed, and total concentrations of target PFAS ranged from 169.3 to 5,046.8 ng/L. Trifluoroacetic acid (TFA) was ubiquitous and dominant across all matrices, whereas elevated concentrations of trifluoromethanesulfonic acid (TFMS; up to 4,858.8 ng/L) and perfluoropropionic acid (PFPrA; up to 744.6 ng/L) were observed in surface waters adjacent to industrial complexes, consistent with possible localized industrial influence. Principal component analysis (PCA) suggested partially distinct compositional tendencies among industrially influenced surface waters, wastewater, and tap water samples. In addition, HRMS-based suspect screening tentatively annotated six PFAS beyond the predefined target list, providing qualitative insight into potentially broader PFAS diversity. Screening-level comparisons with sum-based benchmark frameworks indicated that cumulative PFAS burdens may be environmentally relevant even when individual compounds remain below available reference values. This study provides multi-matrix assessment of short- and ultrashort-chain PFAS in aquatic systems of South Korea, and matrix-specific occurrence profiles, compositional tendencies associated with industrially influenced waters, and the contribution of ultrashort-chain PFAS to cumulative PFAS burdens.