title: Temporal trends for inflow of perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) to Tokyo Bay, Japan, estimated by a receptor-oriented approach.
abstract: We estimated inflow rates of perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) to Tokyo Bay, Japan, between February 2004 and February 2011 by a receptor-oriented approach based on quarterly samplings of the bay water. Temporal trends in these inflow rates are an important basis for evaluating changes in PFOS and PFOA emissions in the Tokyo Bay catchment basin. A mixing model estimated the average concentrations of these compounds in the freshwater inflow to the bay, which were then multiplied by estimated freshwater inflow rates to obtain the inflow rates of these compounds. The receptor-oriented approach enabled us to comprehensively cover inflow to the bay, including inflow via direct discharge to the bay. On a logarithmic basis, the rate of inflow for PFOS decreased gradually, particularly after 2006, whereas that for PFOA exhibited a marked stepwise decrease from 2006 to 2007. The rate of inflow for PFOS decreased from 730kg/y during 2004-2006 to 160kg/y in 2010, whereas that for PFOA decreased from 2000kg/y during 2004-2006 to 290kg/y in 2010. These reductions probably reflected reductions in the use and emission of these compounds and their precursors in the Tokyo Bay catchment basin. Our estimated per-person inflow rates (i.e., inflow rates divided by the estimated population in the basin) for PFOS were generally comparable to previously reported per-person waterborne emission rates in Japan and other countries, whereas those for PFOA were generally higher than previously reported per-person waterborne emission rates. A comparison with previous estimates of household emission rates of these compounds suggested that our inflow estimates included a considerable contribution from point industrial sources.
authors.affiliation: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan. Electronic address: tsakurai@nies.go.jp.
authors.forename: Takeo
authors.initials: T
authors.lastname: Sakurai
authors.affiliation: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan.
authors.forename: Shigeko
authors.initials: S
authors.lastname: Serizawa
authors.affiliation: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan; Faculty of Environmental & Symbiotic Sciences, Prefectural University of Kumamoto, 3-1-100 Tsukide, Kumamoto, Kumamoto 862-8502, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Kobayashi
authors.affiliation: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan.
authors.forename: Keita
authors.initials: K
authors.lastname: Kodama
authors.affiliation: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan; Southeast Sea Fisheries Research Institute, National Fisheries Research and Development Institute, Tongyeong, Gyeongnam 650-943, Republic of Korea.
authors.forename: Jeong-Hoon
authors.initials: JH
authors.lastname: Lee
authors.affiliation: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Maki
authors.affiliation: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan; National Institute of Advanced Industrial Science and Technology, 16-1 Onogawa, Tsukuba, Ibaraki 305-8569, Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Zushi
authors.affiliation: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan.
authors.forename: Janice Beltran
authors.initials: JB
authors.lastname: Sevilla-Nastor
authors.affiliation: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Imaizumi
authors.affiliation: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Suzuki
authors.affiliation: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Horiguchi
authors.affiliation: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Shiraishi
mesh_terms: D017738:Alkanesulfonic Acids / Q000032:analysis*; D061006:Bays / Q000737:chemistry*; D002210:Caprylates / Q000032:analysis*; D004784:Environmental Monitoring; D005466:Fluorocarbons / Q000032:analysis*; D014041:Tokyo; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D017738:Alkanesulfonic Acids; D002210:Caprylates; D005466:Fluorocarbons; D014874:Water Pollutants, Chemical; C023036:perfluorooctanoic acid; C076994:perfluorooctane sulfonic acid
keywords: Catchment basin; Emission source; Inflow rate; Perfluoroalkyl substances; Receptor-oriented analysis; Surface water