title: Historical occurrences of polybrominated diphenyl ethers and polychlorinated biphenyls in Manila Bay, Philippines, and in the upper Gulf of Thailand.
abstract: Historical trends of the accumulation of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in a typical tropical Asian environment were investigated using radio-dated sediment cores from Manila Bay, the Philippines and from the upper Gulf of Thailand. Vertical profiles indicated earlier usage of PCBs than of PBDEs which coincided with their industrial production. The increasing concentrations of total PBDEs and PCBs toward the surface suggested an increased consumption of PBDEs; and possible leakage of PCBs from old machineries into the aquatic environment in recent years. Current input of PCBs to the catchment of Manila Bay was supported by the analyses of air samples and plastic resin pellets. The vertical profiles of total PBDEs in the cores (i.e., rapidly increasing concentrations corresponding to the mid-1980s until mid-1990s, followed by a decrease until the early 2000s, and increasing again toward the surface) likely corresponded to the rapid economic growth in Asia in the 1990s, the Asian financial crisis in 1997, and the economic recovery since early 2000s. BDE-209 was predominant especially on the surface layers. BDEs 47 and 99 generally decreased toward the surface, reflecting the phase-out of the technical penta-PBDE products and the regulation by the Stockholm Convention in recent years. Increasing ratios of BDE-202/209, 206/209, 207/209 and decreasing % of BDE-209 down the core layers may provide evidence for the anaerobic debromination of BDE-209 in the sediment cores. Inventories in ng/cm(2) of total PCBs were higher than total PBDEs (92 vs. 34 and 47 vs. 11 in the Philippines; 47 vs. 33 in Thailand). However, the doubling times indicated faster accumulation of total PBDEs (6-7 years) and BDE-209 (6-7.5 years) than of PCBs (8-11 years). Furthermore, the temporal increase in BDE-209 was comparable to or faster than those reported in other water bodies around the world.
authors.affiliation: Laboratory of Organic Geochemistry, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan; Natural Sciences Research Institute, University of the Philippines Diliman, Quezon City 1101, Philippines.
authors.forename: Charita S
authors.initials: CS
authors.lastname: Kwan
authors.affiliation: Laboratory of Organic Geochemistry, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan. Electronic address: shige@cc.tuat.ac.jp.
authors.forename: Hideshige
authors.initials: H
authors.lastname: Takada
authors.affiliation: Environmental Research and Training Center, Pathumthani 12120, Thailand.
authors.forename: Ruchaya
authors.initials: R
authors.lastname: Boonyatumanond
authors.affiliation: School of Marine Science and Technology, Tokai University, Shizuoka 424-8610, Japan.
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Kato
authors.affiliation: Laboratory of Organic Geochemistry, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan.
authors.forename: Kaoruko
authors.initials: K
authors.lastname: Mizukawa
authors.affiliation: Laboratory of Organic Geochemistry, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan.
authors.forename: Maki
authors.initials: M
authors.lastname: Ito
authors.affiliation: Institute of Marine Environment and Resources, Vietnam Academy of Science and Technology, 246 Danang, Haiphong 35000, Vietnam.
authors.forename: Le Quang
authors.initials: le Q
authors.lastname: Dung
authors.affiliation: Faculty of Environmental Studies, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor Darul Ehsan, Malaysia.
authors.forename: Mohamad Pauzi
authors.initials: MP
authors.lastname: Zakaria
authors.affiliation: Natural Sciences Research Institute, University of the Philippines Diliman, Quezon City 1101, Philippines.
authors.forename: Evangeline C
authors.initials: EC
authors.lastname: Santiago
mesh_terms: D061006:Bays / Q000737:chemistry*; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000737:chemistry; D055768:Halogenated Diphenyl Ethers / Q000032:analysis*; D010679:Philippines; D011078:Polychlorinated Biphenyls / Q000032:analysis*; D013785:Thailand; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D055768:Halogenated Diphenyl Ethers; D014874:Water Pollutants, Chemical; D011078:Polychlorinated Biphenyls
keywords: Anaerobic debromination; PBDEs; PCBs; Passive air sample; Pellet watch; Sediment cores