Beyond the Tip of the Iceberg: Suspect Screening Reveals Point Source-Specific Patterns of Emerging and Novel Per- and Polyfluoroalkyl Substances in German and Chinese Rivers

Only a few dozens of the several thousand existing per- and polyfluoroalkyl substances (PFAS) are monitored usingconventional target analysis. This study employed suspectscreening to examine patterns of emerging and novel PFAS inGerman and Chinese river water affected by industrial pointsources. In total, 86 PFAS were (tentatively) identified andgrouped into 18 structure categories. Homologue patterns revealeddistinct differences betweenfluoropolymer production sites of thetwo countries. In the Chinese Xiaoqing River Basin, the C8homologue was the most prevalent compound of the emergingseries of chlorinated perfluoroalkyl carboxylic acids (Cl-PFCAs)and perfluoroalkylether carboxylic acids (PFECAs). In contrast, C6and shorter homologues were dominant in the German Alz River.This indicates that the phaseout of long-chain compounds in Europe and their ongoing production in Asian countries also apply tounregulated emerging PFAS classes. Additional characteristics to differentiate the point sources were the peak area ratio ofperfluorobutane sulfonic acid (PFBS) versus the emerging compound hydro-substituted PFBS (H-PFBS) as well as the occurrenceof byproducts of the sulfonated tetrafluoroethylene-based polymer Nafion. The large number of identified unregulated PFASunderlines the importance of a grouping approach on a regulatory level, whereas the revealed contamination patterns can be used toestimate, prioritize, and minimize contributions of specific sources