title: Weak size dependence of resuspended radiocesium adsorbed on soil particles collected after the Fukushima nuclear accident.
abstract: Most studies of the properties of airborne radionuclides emitted from the Fukushima Daiichi Nuclear Power Plant have focused on the relatively early stages of the accident, and little is known about the characteristics of radiocesium in the long-term. In this study, we analyzed activity size distributions of airborne radiocesium collected over 5 months in Tsukuba, Japan. Radiocesium in the accumulation mode size range (0.1-2 μm in aerodynamic diameter) was overwhelming in the early aerosol samples and decreased with time, while that associated with coarse aerosols remained airborne. We examined the radiocesium adsorbed onto airborne soil particles, and found that the size dependence of137Cs surface density adsorbed on soil particles was weak. That is, radiocesium was distributed homogeneously throughout the aerodynamic diameter range of 2.1-11 μm. This characteristic may be related to the reported structure of radiocesium-bearing soil particles collected from the ground, which consisted of an aggregate of specific clay minerals and other non-cesium adsorbing particles. The resuspension factors for the first two aerosol samples collected during late April and May 2011 were close to those in European cities in the months following the Chernobyl accident, despite different soil and weather conditions.
authors.affiliation: National Institute of Advanced Industrial Science and Technology, 16-1 Onogawa, Tsukuba 305-8569, Japan. Electronic address: kane.n@aist.go.jp.
authors.forename: Naoki
authors.initials: N
authors.lastname: Kaneyasu
authors.affiliation: Tokyo University of Marine Science and Technology, 4-5-7 Kounan, Minato-ku, Tokyo 108-8477, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Ohashi
authors.affiliation: Tokyo University of Marine Science and Technology, 4-5-7 Kounan, Minato-ku, Tokyo 108-8477, Japan.
authors.forename: Fumie
authors.initials: F
authors.lastname: Suzuki
authors.affiliation: Keio University, 3-14-1 Hiyoshi, Kouhoku-ku, Yokohama 223-8522, Japan.
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Okuda
authors.affiliation: Nagoya City Institute for Environmental Sciences, 5-16-8 Toyoda, Nagoya 457-0841, Japan.
authors.forename: Fumikazu
authors.initials: F
authors.lastname: Ikemori
authors.affiliation: National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292, Japan.
authors.forename: Naofumi
authors.initials: N
authors.lastname: Akata
authors.affiliation: Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Kogure
mesh_terms: D002588:Cesium Radioisotopes / Q000032:analysis*; D062406:Fukushima Nuclear Accident; D007564:Japan; D011834:Radiation Monitoring; D012990:Soil Pollutants, Radioactive / Q000032:analysis*
chemical_list: D002588:Cesium Radioisotopes; D012990:Soil Pollutants, Radioactive
keywords: (137)Cs; Fukushima nuclear accident; Radionuclides; Resuspension; Soil dust particles; Surface density