title: Characteristics of the abundance of polychlorinated dibenzo-p-dioxin and dibenzofurans, and dioxin-like polychlorinated biphenyls in sediment samples from selected Asian regions in Can Gio, Southern Vietnam and Osaka, Japan.
abstract: The levels of polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/PCDFs), and dioxin-like polychlorinated biphenyls (DL-PCBs) were determined in sediment samples from Can Gio, South Vietnam, and Osaka, Japan. Can Gio is known for the defoliation of its mangrove forests by aerial spraying with Agent Orange during the Vietnam War, whereas Osaka is renowned for a PCDD/PCDF pollution accident at a municipal solid-waste incinerator. For comparison, we also analyzed PCDD/PCDFs and DL-PCBs in sediment samples from Hue and Hanoi, Vietnam. The toxic equivalent quantity (TEQ) values in Can Gio were as high as those in Hue, Hanoi, and suburban areas of Osaka, but much lower than those in urban areas of Osaka. The proportion of the World Health Organization (WHO)-TEQ value contributed by 2,3,7,8-tetrachlorinated dibenzo-p-dioxin (TCDD) in Can Gio was approximately 30%, higher than the values in the other sample areas. These data suggest that residual sedimentary TCDD that originated from aerial spraying of Agent Orange occur in only low concentrations in Can Gio. The main contributors to WHO-TEQ values in Can Gio are natural sources, as in Hue. In contrast, commercial PCBs are the dominant contributors to WHO-TEQ values in Hanoi. In Osaka, agrochemicals used in rice cultivation, the incineration of solid waste, and commercial PCBs equally contributed to WHO-TEQ values at suburban locations. The dumping of incinerator-related materials and/or the inadequate management of commercial PCBs have resulted in significantly elevated WHO-TEQ values of 240-370 ng kg(-1)dw at urban locations in Osaka.
authors.affiliation: Research Institute for Environment, Agriculture, and Fisheries, Osaka Prefectural Government, 1-3-62 Nakamichi, Higashinari-ku, Osaka 537-0025, Japan. kishida82477@iris.eonet.ne.jp
authors.forename: Masao
authors.initials: M
authors.lastname: Kishida
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Imamura
authors.forename: Norimichi
authors.initials: N
authors.lastname: Takenaka
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Maeda
authors.forename: Pham Hung
authors.initials: PH
authors.lastname: Viet
authors.forename: Akira
authors.initials: A
authors.lastname: Kondo
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Bandow
mesh_terms: D015085:2,4,5-Trichlorophenoxyacetic Acid / Q000737:chemistry; D015084:2,4-Dichlorophenoxyacetic Acid / Q000737:chemistry; D000075182:Agent Orange; D001208:Asia; D001572:Benzofurans / Q000032:analysis* / Q000737:chemistry; D019015:Geologic Sediments / Q000032:analysis* / Q000737:chemistry; D017745:Incineration; D007564:Japan; D011078:Polychlorinated Biphenyls / Q000032:analysis* / Q000737:chemistry; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry; D011108:Polymers / Q000032:analysis* / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis* / Q000737:chemistry; D014744:Vietnam
chemical_list: D001572:Benzofurans; D000072317:Polychlorinated Dibenzodioxins; D011108:Polymers; D012989:Soil Pollutants; C016068:polychlorodibenzofuran; D015084:2,4-Dichlorophenoxyacetic Acid; D000075182:Agent Orange; D015085:2,4,5-Trichlorophenoxyacetic Acid; D011078:Polychlorinated Biphenyls