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Cs transfer from soils contaminated by resuspended particles to Japanese mustard spinach in difficult-to-return zone of Fukushima辰野 宇大*; 二瓶 直登*; 吉村 和也; 大手 信人*
Journal of Radioanalytical and Nuclear Chemistry, 332(6), p.1677 - 1686, 2023/06
This study investigated the transfer of Cs to crops and soil contamination by resuspended particles derived from airborne and ground surface. We conducted the cultivation test of a Japanese mustard spinach in pot placed at study fields. The soil in pots might be mainly contaminated by soil particles derived from the ground surface, and Cs transferred to the spinaches was observed. However, the proportion of water-exchangeable and organic fractions of Cs in the resuspended particles derived from airborne was greater than that from ground surface, resulting in the greater Cs transfer factor. Therefore, it is important to grasp the source of resuspended particles.
辰野 宇大*; 脇 嘉理*; 角間 海七渡*; 二瓶 直登*; 高瀬 つぎ子*; 和田 敏裕*; 吉村 和也; 中西 貴宏; 大手 信人*
Journal of Environmental Management, 329, p.116983_1 - 116983_13, 2023/03
被引用回数：0 パーセンタイル：0(Environmental Sciences)This study investigated the effect of radioactive cesium-rich microparticles (CsMPs) on the radiocesium (RCs) concentration and distribution coefficient (Kd) in two rivers, Takase River and Kami-Oguni River, flowing in the watersheds with different radioactive contaminated conditions in Fukushima Prefecture. Unlike RCs adsorbed on to the suspended solids (SS), there was no correlation between the RCs concentration derived from CsMPs and the SS concentration in both rivers. Inflow of CsMPs to the targeted rivers was contingent. CsMPs were detected only in some samples during rainfall. Furthermore, the proportion of RCs concentration derived from CsMPs in the average RCs concentrations per unit mass of SS in both rivers during rainfall were not large, which were 10% or less. As a results, CsMPs did not significantly increase particulate RCs concentration and had little effect on Kd in both river water flowing the watershed with different RCs contaminated condition.
辰野 宇大*; 脇 嘉理*; 角間 海七渡*; 二瓶 直登*; 和田 敏裕*; 吉村 和也; 中西 貴宏; 大手 信人*
Radiation Protection Dosimetry, 198(13-15), p.1052 - 1057, 2022/09
被引用回数：1 パーセンタイル：62.84(Environmental Sciences)Cesium-rich microparticles (CsMPs) with high cesium-137 (Cs) concentrations were released and deposited in surface soil after the Fukushima Daiichi Nuclear Power Plant accident. Radioactive materials on the soil surface layer enter rivers owing to soil erosion during rainfall. In this study, we investigated CsMPs runoff through the river via soil erosion during rainfall in the Takase River watershed in Namie Town, Fukushima Prefecture, Japan. CsMPs were rarely detected in suspended solids (SS) in water samples collected during four rainfalls between February and July 2021. Furthermore, the proportion of Cs concentration derived from CsMPs to Cs concentration in the form of SS (particulate Cs) in the water was 
6% on average, which suggests that Cs runoff in the form of CsMPs from the forest to the Takase River was not large.
二瓶 直登*; 吉村 和也; 奥村 大河*; 田野井 慶太朗*; 飯島 和毅; 小暮 敏博*; 中西 友子*
Journal of Radioanalytical and Nuclear Chemistry, 318(1), p.341 - 346, 2018/10
被引用回数：2 パーセンタイル：24.05(Chemistry, Analytical)Komatsuna (
) was cultivated in pots using non-contaminated soil and water, and the pots were arranged 30, 60, and 120 cm above the ground surface. The experiment site was located 4.5 km from the Fukushima Daiichi Nuclear Power Plant and had an ambient dose rate of approximately 1.4 
Sv/h. The radiocesium concentration in the above ground parts without washing ranged from 22 to 333 Bq/kg (dry weight). The radiocesium concentration in the washed plants was predominantly lower than in the un-washed plants. Komatsuna cultivated lower to the ground tended to have a higher radiocesium concentration. Therefore, it can be posited that radiocesium detected in Komatsuna leaves was derived from ground surface.
二瓶 直登*; 吉村 和也; 中西 友子*
no journal, ,
The purpose of this study was to assess radiocesium migration to crops caused by external adsorption and internal absorption and to analyze the fallout matter to show the cause of the radiocesium migration. Japanese mustard spinach was cultivated using noncontaminated soil and water in a pot at six sites in Fukushima prefecture in 2018. The plants were washed with water after havesting, and then measured radiocesium concentration which was supposed to indicate internal absorption. Fallout matter was also collected using basins filled with water during the cultivation. The radiocesium concentrations in spinach varied with the cultivation place and time. Most radiocesium in the fallout matter was in the suspended phase, but the radiocesium concentration in the spinach was highly correlated with the dissolved radiocesium in the fallout matter. Internal absorption is considered to absorb dissolved radiocesium in the fallout matter from leaves directly or from roots indirectly.
二瓶 直登*; 吉村 和也
no journal, ,
本研究は、再浮遊した放射性Csの作物への移行量とその要因を検討した。供試作物としてコマツナを用い、大熊町, 富岡町で非汚染土壌、非汚染水を用いてポット栽培した。併せて大気降下物中の放射性Cs量を評価するためポット脇に容器に入れた水も設置した。コマツナ地上部の放射性Cs濃度は4-57Bq kg
(乾物重)、降下物は15-370Bq m
であり、同場所においても季節により変動した。収穫後水洗浄したコマツナの放射性Cs濃度は洗浄前に比べて低下した。更に、地際30cmで栽培したコマツナの放射性Cs濃度は120cmで栽培したコマツナに比べて高く、地表面からの再浮遊物の影響が想定された。
辰野 宇大*; 脇 嘉理*; 角間 海七渡*; 二瓶 直登*; 村上 正志*; 中西 貴宏; 吉村 和也; 大手 信人*
no journal, ,
森林における高濃度放射性セシウム含有微粒子(CsMPs)の(鉛直)分布や土壌中Cs濃度への寄与を評価すると共に、降雨時の河川へのCsMPs流入と懸濁態Cs濃度,分配係数に与える影響を評価することを目的とし、高瀬川流域を対象に調査を行った。調査の結果、CsMPsは森林土壌の表層に多くがとどまるが、表層の土壌中Cs濃度への寄与は数%程度であった。また、河川水中の懸濁態Cs濃度や分配係数に及ぼす影響は限定的であることが示された。
