Per- and Polyfluoroalkyl Substances in Representative Fluorocarbon Surfactants Used in Chinese Film-Forming Foams: Levels, Profile Shift, and Environmental Implications

China is among the largest producers and consumers of aqueous firefighting foams that contain fluorocarbon surfactants. Despite global phase-out initiatives of long chain “C8” perfluoroalkyl chemicals, perfluorooctanesulfonate is not banned yet in China. However, some manufacturers are voluntarily developing and producing short chain alternative fluorosurfactant products for foreign markets. Quantification of perfluoroalkyl substances and their precursors (by total oxidizable precursor assay) in fluorosurfactants used for the preparation of aqueous film-forming foams in China demonstrates that perfluorooctanesulfonate and perfluorooctanoate are still significantly present in certain domestic products. However, such compounds, as well as the other long chain homologues, are not detected in alternative products (produced in China for use abroad). In particular, such products are based on telomerization and seem to evolve toward smaller amounts of fluorinated chemicals and shorter chain fluoroalkyl compounds...