title: Vertical distribution of radiocesium in coniferous forest soil after the Fukushima nuclear power plant accident.
abstract: This study deals with the description of the vertical distribution of radiocaesium ((137)Cs and (134)Cs) in a representative coniferous forest soil, investigated 10 months after the Fukushima radioactive fallout. During soil sampling, the forest floor components (understory plants, litter (Ol-) and fermented layers (Of)) were collected and treated separately. The results indicate that radiocesium is concentrated in the forest floor, and high radiocesium transfer factor observed in the undergrowth plants (3.3). This made the forest floor an active exchanging interphase for radiocesium. The raw organic layer (Ol + Of) holds 52% (5.3 kBq m(-2)) of the Fukushima-derived and 25% (0.7 kBq m(-2)) of the pre-Fukushima (137)Cs at the time of the soil sampling. Including the pre-Fukushima (137)Cs, 99% of the total soil inventory was in the upper 10 cm, in which the organic matter (OM) content was greater than 10%, suggesting the subsequent distribution most likely depends on the OM turnover. However, the small fraction of the Fukushima-derived (137)Cs at a depth of 16 cm is most likely due to the infiltration of radiocesium-circumscribed rainwater during the fallout before that selective adsorption prevails and reduces the migration of soluble (137)Cs. The values of the depth distribution parameters revealed that the distribution of the Fukushima-derived (137)Cs was somewhat rapid.
authors.affiliation: Center for Research in Isotopes and Environmental Dynamic, University of Tsukuba, Tennodai 1-1-1, Tsukuba shi, Ibaraki 305-8572, Japan. Electronic address: teramaget@yahoo.com.
authors.forename: Mengistu T
authors.initials: MT
authors.lastname: Teramage
authors.affiliation: Center for Research in Isotopes and Environmental Dynamic, University of Tsukuba, Tennodai 1-1-1, Tsukuba shi, Ibaraki 305-8572, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Onda
authors.affiliation: Center for Research in Isotopes and Environmental Dynamic, University of Tsukuba, Tennodai 1-1-1, Tsukuba shi, Ibaraki 305-8572, Japan.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Patin
authors.affiliation: Center for Research in Isotopes and Environmental Dynamic, University of Tsukuba, Tennodai 1-1-1, Tsukuba shi, Ibaraki 305-8572, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kato
authors.affiliation: Department of International Environmental and Agriculture Science, Tokyo University of Agriculture and Technology, Fuchuu, Tokyo 183-8509, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Gomi
authors.affiliation: Department of International Environmental and Agriculture Science, Tokyo University of Agriculture and Technology, Fuchuu, Tokyo 183-8509, Japan.
authors.forename: Sooyoun
authors.initials: S
authors.lastname: Nam
mesh_terms: D002588:Cesium Radioisotopes / Q000032:analysis* / Q000378:metabolism*; D029780:Chamaecyparis / Q000378:metabolism*; D065928:Forests; D062406:Fukushima Nuclear Accident; D007564:Japan; D011834:Radiation Monitoring; D012990:Soil Pollutants, Radioactive / Q000032:analysis* / Q000378:metabolism*; D013051:Spectrometry, Gamma
chemical_list: D002588:Cesium Radioisotopes; D012990:Soil Pollutants, Radioactive
keywords: (134)Cs; (137)Cs; Deposition; Forest floor; Migration; Radiocesium