title: Spatial distribution and importance of potential perfluoroalkyl acid precursors in urban rivers and sewage treatment plant effluent--case study of Tama River, Japan.
abstract: Production and use of perfluorooctane sulfonate (PFOS) is regulated worldwide. However, numerous potential precursors that eventually decompose into PFOS and other perfluoroalkyl acids (PFAAs) such as perfluorooctanoic acid (PFOA) are still being used and have not been studied in detail. Therefore, knowledge about the levels and sources of the precursors is essential. We investigated the total concentration of potential PFAA precursors in the Tama River, which is one of the major rivers flowing into the Tokyo Bay, by converting all the perfluorinated carboxylic acid (PFCA) and perfluoroalkyl sulfonic acid (PFSA) precursors into PFCAs by chemical oxidation. The importance of controlling PFAA precursors was determined by calculating the ratios of PFCAs formed by oxidation to the PFAAs originally present (ΣΔ[PFCAC4-C12]/Σ[PFAAs]before oxidation) (average = 0.28 and 0.69 for main and tributary branch rivers, respectively). Higher total concentrations of Δ[PFCAs] were found in sewage treatment plant (STP) effluents. However, the ratios found in the effluents were lower (average = 0.21) than those found in the river water samples, which implies the decomposition of some precursors into PFAAs during the treatment process. On the other hand, higher ratios were observed in the upstream water samples and the existence of emission sources other than the STP effluents was indicated. This study showed that although the treatment process converting a part of the PFAA precursors into PFAAs, STPs were important sources of precursors to the Tama River. To reduce the levels of PFAAs in the aquatic environment, it is necessary to reduce the emission of the PFAA precursors as well.
authors.affiliation: Faculty and Graduate School of Environment and Information Sciences, Yokohama National University, Yokohama 240-8501, Japan. Electronic address: ye-feng-fy@ynu.jp.
authors.forename: Feng
authors.initials: F
authors.lastname: Ye
authors.affiliation: Faculty and Graduate School of Environment and Information Sciences, Yokohama National University, Yokohama 240-8501, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Tokumura
authors.affiliation: Faculty and Graduate School of Environment and Information Sciences, Yokohama National University, Yokohama 240-8501, Japan.
authors.forename: Md Saiful
authors.initials: MS
authors.lastname: Islam
authors.affiliation: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Zushi
authors.affiliation: Faculty and Graduate School of Environment and Information Sciences, Yokohama National University, Yokohama 240-8501, Japan.
authors.forename: Jungkeun
authors.initials: J
authors.lastname: Oh
authors.affiliation: Faculty and Graduate School of Environment and Information Sciences, Yokohama National University, Yokohama 240-8501, Japan.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Masunaga
mesh_terms: D017738:Alkanesulfonic Acids / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D002947:Cities; D004784:Environmental Monitoring / Q000379:methods / Q000706:statistics & numerical data*; D005466:Fluorocarbons / Q000032:analysis*; D005843:Geography; D007564:Japan; D010084:Oxidation-Reduction; D045483:Rivers / Q000737:chemistry*; D053719:Tandem Mass Spectrometry; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D017738:Alkanesulfonic Acids; D005466:Fluorocarbons; D014874:Water Pollutants, Chemical; C076994:perfluorooctane sulfonic acid
keywords: Effluent; Oxidation; Perfluorinated; Perfluoroalkyl acid precursor; Sewage treatment plant; Tama River