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Yang, B.*; 恩田 裕一*; 脇山 義史*; 吉村 和也; 関本 均*; Ha, Y.*
Environmental Pollution, 208(Part B), p.562 - 570, 2016/01
被引用回数：5 パーセンタイル：55.17(Environmental Sciences)In this study, we investigated the temporal changes of radiocesium in soil, irrigation water, and rice plant in two adjacent rice paddies, with and without surface-soil-removal practice, in Fukushima Prefecture for over three years (2012 to 2014). Our results showed that radiocesium migrated into 24-28 cm soil layers and that the concentration and inventory of radiocesium in paddy soils generally decreased. The newly added radiocesium to paddies through irrigation water contributed only the maximum values of 0.15% and 0.75% of the total amount present in normal and decontaminated paddies, respectively, throughout the study period. The change trend of radiocesium concentration in suspended sediment in irrigation water exponentially decreased. Radiocesium accumulation in rice plant also decreased with time in both paddies. However, the transfer factor of radiocesium for rice plant in the decontaminated paddy increased compared with normal paddy.
脇山 義史*; 恩田 裕一*; 吉村 和也; 中村 典子*; 馬目 凌*
no journal, ,
This study shows approximately three years observation results of plot-scale Cs-137 wash-off at various land uses in Kawamata town after the accident of FDNPP. Soil erosion rate were positively correlated with vegetation cover on undisturbed soils, whereas high erosion rate were found on cultivated farmlands even with similar vegetation cover to uncultivated farmlands. Annual Cs-137 wash-off rate ranged from 0.003 to 9.3 %/year and the largest was from uncultivated farmland followed by cultivated farmlands. Decreasing trends of Cs-137 concentration were found on uncultivated farmlands, whereas no trend was found on other plots. Our results suggest that the active soil erosion results in decrease in Cs-137 concentration of sediments on uncultivated slopes, while cultivation resulted in the no trend of temporal decrease in Cs-137 concentration due to constant vertical distribution of Cs-137.
吉村 和也; 脇山 義史*; 恩田 裕一*; 高瀬 つぎ子*
no journal, ,
This study presents Cs-137 wash-off observations on various land uses including decontaminated lands in Fukushima. We established rectangle soil erosion plots on six landscape; uncultivated farmland (UFL), cultivated farmland (CFL), grassland (GL), forest (F), uncultivated and cultivated farmlands on a decontaminated land (D-UFL and D-CFL). The D-UFL and DCFL were established after the decontamination of erosion plots. Mean Cs-137 concentrations on decontaminated lands decreased down to approx. 10 to 40 % of values observed before decontamination. No significant difference in amount of eroded sediment was found between contaminated and decontaminated lands, suggesting that decontamination works decrease total Cs-137 wash-off.
