Toward a Comprehensive Global Emission Inventory of C4–C10 Perfluoroalkanesulfonic Acids (PFSAs) and Related Precursors: Focus on the Life Cycle of C6- and C10-Based Products

A first global emission inventory of C4–C10 perfluoroalkanesulfonic acids (PFSAs) released during the life cycle of perfluorohexanesulfonyl fluoride (PHxSF)- and perfluorodecanesulfonyl fluoride (PDSF)-based products is presented. This study complements previous research on emissions of PFSAs that focused largely on the life cycle of perfluorooctanesulfonyl fluoride (POSF) and its derivatives. It reviews and integrates existing information about the life cycle of PHxSF, PDSF, and their derivatives; the limited data available in the public domain point to potentially significant global production, uses, and releases of these substances. Between 1958 and 2015, ranges of total emissions of perfluorohexanesulfonic acid (PFHxS) and perfluorodecanesulfonic acid (PFDS) are estimated to be 120–1022 and 38–378 metric tons, respectively. With the new emission estimates as inputs in a global multimedia environmental fate model (CliMoChem), the model-derived environmental concentrations well capture the reported field concentrations, providing strong support for the plausibility of the developed emission inventories. The results highlight the ongoing environmental exposure to these substances and the need for more detailed data in the public domain about their production levels and uses.