title: Distribution and characteristics of methylmercury in surface sediment in Minamata Bay.
abstract: This study was carried out to evaluate the present-day chemical properties of methylmercury in surface sediment in Minamata Bay where a dredging project was completed 28years ago. Present-day sediment from Minamata Bay consists of sandy silt, and the average loss-on-ignition in surface sediment was 7.0±2.3%. The average methylmercury concentrations in the upper sediment layers were significantly higher than those in the lower sediment layers. Currently, the concentrations in sediments in Minamata Bay do not exceed the Japanese regulatory standard value for mercury. The average concentration of methylmercury in Minamata Bay surface sediment was 1.74±1.0ng/g on a dry weight basis (n=107). The methylmercury concentration in Minamata Bay surface sediment was almost 16 times higher than that in surface sediment from Isahaya Bay surface sediment, which was 0.11±0.045ng/g on a dry weight basis (n=5).
authors.affiliation: Environmental Chemistry Section, Department of Environmental Science and Epidemiology, National Institute for Minamata Disease, 4058-18 Hama, Minamata, Kumamoto 867-0008, Japan. Electronic address: matsuyam@nimd.go.jp.
authors.forename: Akito
authors.initials: A
authors.lastname: Matsuyama
authors.affiliation: Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan. Electronic address: yano@civil.kyushu-u.ac.jp.
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Yano
authors.affiliation: Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Hisano
authors.affiliation: Environmental Chemistry Section, Department of Environmental Science and Epidemiology, National Institute for Minamata Disease, 4058-18 Hama, Minamata, Kumamoto 867-0008, Japan.
authors.forename: Michiaki
authors.initials: M
authors.lastname: Kindaichi
authors.affiliation: Environmental Chemistry Section, Department of Environmental Science and Epidemiology, National Institute for Minamata Disease, 4058-18 Hama, Minamata, Kumamoto 867-0008, Japan.
authors.forename: Ikuko
authors.initials: I
authors.lastname: Sonoda
authors.affiliation: Environmental Chemistry Section, Department of Environmental Science and Epidemiology, National Institute for Minamata Disease, 4058-18 Hama, Minamata, Kumamoto 867-0008, Japan; Faculty of Engineering, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan. Electronic address: atada@nagasaki-u.ac.jp.
authors.forename: Akihide
authors.initials: A
authors.lastname: Tada
authors.affiliation: International Mercury Laboratory Inc., Minamata, Kumamoto 867-0034, Japan. Electronic address: h610akagi@ybb.ne.jp.
authors.forename: Hirokatsu
authors.initials: H
authors.lastname: Akagi
mesh_terms: D061006:Bays / Q000737:chemistry; D019015:Geologic Sediments / Q000737:chemistry*; D007564:Japan; D008628:Mercury; D008767:Methylmercury Compounds; D014874:Water Pollutants, Chemical
chemical_list: D008767:Methylmercury Compounds; D014874:Water Pollutants, Chemical; D008628:Mercury
keywords: Isahaya Bay; Methylmercury; Minamata Bay; Sediment; Spatial distribution