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Cs in organic layer and mineral soil in Japanese forests; Four-year observation and model analysisMuto, Kotomi; Atarashi-Andoh, Mariko; Matsunaga, Takeshi*; Koarashi, Jun
Journal of Environmental Radioactivity, 208-209, p.106040_1 - 106040_10, 2019/11
Times Cited Count：16 Percentile：43.09(Environmental Sciences)Vertical distributions of Cs in the soil profile were observed at five forest sites with different vegetation types for 4.4 years after the Fukushima Dai-ichi Nuclear Power Plant accident, and Cs migration in the organic layer and mineral soil was analyzed based on a comparison of models and observations. Cesium-137 migration from the organic layer was faster than that observed in European forests, suggesting that the mobility and bioavailability of Cs could be suppressed rapidly in Japanese forests. The diffusion coefficients of Cs in the mineral soil were estimated to be 0.042-0.55 cm
y
, which were roughly comparable with those of European forest soils affected by the Chernobyl Nuclear Power Plant accident. Model predictions indicated Cs mainly distributed in the surface mineral soil at 10 years after the accident. It suggest that the Cs deposited onto Japanese forest ecosystems will be retained in the surface layers of mineral soil for a long time.
C, Cs and stable carbon composition in forest soil and its implicationsGuo, J.; Atarashi-Andoh, Mariko; Amano, Hikaru
Journal of Radioanalytical and Nuclear Chemistry, 255(1), p.223 - 229, 2003/01
Times Cited Count：7 Percentile：44.43(Chemistry, Analytical)Soil organic matter content, 
C, C and Cs radioactivity were determined in 3 undisturbed forest soil profiles in Ibaraki prefecture, Japan to estimate C migration in surface environment. The Cs data illustrate that no disturbance has occurred during past years in 3 soil profiles. The peak values are observed in the top 10 cm of the soil profiles. C activities were determined with fast bomb combustion-liquid scintillation counting method. C determination shows that C also has peak values in the top 10 cm of the soil profiles ascribed to the highest bomb C level in 1960's.C values continuously decreased with increasing soil depth. Enrichment of deeper soils in isotope ratio probably results from discrimination against C during mineralization and loss of isotopically lighter carbon from soils due to root uptake, leaching etc.It shows that C is an excellent indicator of soil carbon turnover and belowground process.
Atarashi-Andoh, Mariko; Amano, Hikaru
Environmental Radiochemical Analysis II, p.273 - 279, 2003/00
Because of the long radioactive half-life of C-14, fallout C-14 from former nuclear weapon-tests still remains in soil, and there is a C-14 flux from the soil surface to the atmosphere [1]. Patterns of C-14 enrichment in soil profiles provide important information for estimating carbon turnover and carbon flux from soil. A simple analytical method of C-14 measurement has been developed for measuring C-14 distribution in the terrestrial environment. C-14 specific activities in plants and soils in a forest and a cultivated field were measured by this method. The data were made available to assess the behavior of fallout C-14 in the surface environment.
Iijima, Kazuki; Funaki, Hironori; Oyama, Takuya; Niizato, Tadafumi; Sato, Haruo*; Yui, Mikazu
no journal, ,
Goal of the project is to develop mechanistic models to predict transport behavior of radioelements strongly adsorbed on soil particles from forests to sea through river systems, evaluate evolution of dose, and propose methods to constrain the transport. This study overviewed the behavior of radioactive caesium through one of the river systems in the coastal area of Fukushima. Concequently, caesium is considered to be strongly adsorbed on the soil particles in the transport through the river water system since more than 90% of caesium has still remained within 5 cm from the surface of topsoil in the forest, and the concentration of caesium in the lake water was extremely low. The difference of concentrations of caesium in the sediments in the river water system can be explained by the effect of particle size on the adsorption site density of caesium.
Ishii, Yasuo; Watanabe, Takayoshi; Oyama, Takuya; Sasaki, Yoshito; Abe, Hironobu; Mitachi, Katsuaki; Niizato, Tadafumi
no journal, ,
Mountainous forest is currently one of the most important sources of radioactive cesium released from the Fukushima Daiichi Nuclear Power Plant accident in Fukushima prefecture, which was covered approximately 70% of the land area by the forest. This study reports the changes in concentrations of radioactive cesium in sediments outflowed from the steep mountainous forest of the Abukuma Mountains, Fukushima, during September - December 2015.
