Evaluation of wastewater and street runoff as sources of perfluorinated surfactants (PFSs)

Abstract

Perfluorinated surfactants (PFSs) in wastewater and street runoff in Japan were measured to determine their pathways of travel and utility as indicators of each to water environments. Among PFS species, perfluorooctanesulfonate (PFOS), perfluorooctanoate (PFOA), and perfluorononanoate (PFNA) were dominant in wastewater. PFS concentrations were higher in secondary effluents than in influents, possibly because of biodegradation of their precursors. This was supported by a significant correlation between concentration increases of PFOA and PFNA. Biodegradation of the same precursors probably produced mainly PFOA and secondarily PFNA. Concentrations of perfluorocarboxylates (PFCAs), especially longer- and even-chain PFCAs, in street runoff were equal to or higher than those in wastewater influents and secondary effluents, but PFOS concentrations were lower in street runoff. This result suggests that street runoff potentially contaminates water environments with PFCAs. In street runoff, perfluorodecanoate (PFDA), perfluoroundecanoate (PFUA), and perfluorododecanoate (PFDDA) were abundant along with PFOA and PFNA. PFS profiles in street runoff were significantly different from those in wastewater samples, suggesting that relative proportions of PFSs can be useful as indicators. Four ratios – PFOA/PFOS, PFNA/PFOS, long-chain/(short-chain + long-chain), and even-chain/(even-chain + odd-chain) – were proposed to evaluate the contributions of PFSs from wastewater and street runoff to water environments.