title: Distribution of dissolved and particulate radiocesium concentrations along rivers and the relations between radiocesium concentration and deposition after the nuclear power plant accident in Fukushima.
abstract: This study involved measurement of concentrations of dissolved and particulate radiocesium ((134)Cs and (137)Cs) in river water, and determination of the quantitative relations between the amount of deposited (137)Cs and (137)Cs concentrations in river waters after the Fukushima Daiichi nuclear power plant accident. First, the current concentrations of dissolved and particulate (134)Cs·(137)Cs were determined in a river watershed from 20 sampling locations in four contaminated rivers (Abukuma, Kuchibuto, Shakado, and Ota). Distribution characteristics of different (137)Cs forms varied with rivers. Moreover, a higher dissolved (137)Cs concentration was observed at the sampling location where the (137)Cs deposition occurred much more heavily. In contrast, particulate (137)Cs concentration along the river was quite irregular, because fluctuations in suspended solids concentrations occur easily from disturbance and heavy precipitation. A similar tendency with dissolved (137)Cs distribution was observed for the (137)Cs concentration per unit weight of suspended solids. Regression analysis between deposited (137)Cs and dissolved/particulate (137)Cs concentrations was performed for the four rivers. The results showed a strong correlation between deposited (137)Cs and dissolved (137)Cs, and a relatively weak correlation between deposited (137)Cs and particulate (137)Cs concentration for each river. However, if the particulate (137)Cs concentration was converted to (137)Cs concentration per unit weight of suspended solid, the values showed a strong correlation with deposited (137)Cs.
authors.affiliation: National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8567, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Tsuji
authors.affiliation: National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8567, Japan. Electronic address: t.yasutaka@aist.go.jp.
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Yasutaka
authors.affiliation: National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8567, Japan.
authors.forename: Yoshishige
authors.initials: Y
authors.lastname: Kawabe
authors.affiliation: Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagito, Gifu 501-1193, Japan.
authors.forename: Takeo
authors.initials: T
authors.lastname: Onishi
authors.affiliation: Graduate School of Environmental Studies, Tohoku University, 6-6-20 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8579, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Komai
mesh_terms: D002588:Cesium Radioisotopes / Q000032:analysis*; D062406:Fukushima Nuclear Accident; D007564:Japan; D052638:Particulate Matter / Q000032:analysis*; D011834:Radiation Monitoring; D012044:Regression Analysis; D045483:Rivers / Q000737:chemistry*; D014875:Water Pollutants, Radioactive / Q000032:analysis*
chemical_list: D002588:Cesium Radioisotopes; D052638:Particulate Matter; D014875:Water Pollutants, Radioactive
keywords: Deposition; Dissolved radiocesium; Fukushima; Particulate radiocesium; Regression analysis; River water