title: (134)Cs and ¹³⁷Cs levels in a grassland, 32 km northwest of the Fukushima 1 Nuclear Power Plant, measured for two seasons after the fallout.
abstract: We measured the levels of radioactive caesium (RACs; ¹³⁴Cs and ¹³⁷Cs) in plants and soil in a grassland, 32 km northwest of the Fukushima 1 Nuclear Power Plant, from June 2011 to October 2012. In 2011, the highest RACs levels (¹³⁴Cs + ¹³⁷Cs) in plants and in the 0-5 cm soil layer were approximately 80 kBq per kg dry weight (DW). Forage grasses and clovers in this grassland showed similar RACs levels. On a DW basis, the levels of RACs in these plants tended to increase with increasing biomass over both years, but the absolute levels decreased in 2012. The RACs levels in the soil decreased sharply with soil depth; the RACs level in the 5-10 cm soil layer was only 3 % of that in the 0-5 cm layer. The transfer factor (ratio of radioactivity in plant parts on DW basis to that in the 0-10 cm soil layer) was 0.5 and 1.0 for the aboveground and belowground plant parts, respectively, in 2011, and these values decreased by approximately 50 % in 2012. We discuss the possible mechanisms underlying these trends, and strategies to decrease the level of RACs in plants to the permissible level for forage.
authors: Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan, itera@biol.s.u-tokyo.ac.jp.
authors: Ichiro
authors: I
authors: Terashima
authors: Masae
authors: M
authors: Shiyomi
authors: Hiroo
authors: H
authors: Fukuda
mesh_terms: D001673:Biodegradation, Environmental; D002588:Cesium Radioisotopes / Q000032:analysis / Q000378:metabolism*; D062406:Fukushima Nuclear Accident; D007564:Japan; D029902:Medicago / Q000737:chemistry / Q000378:metabolism; D055848:Nuclear Power Plants; D035261:Plant Components, Aerial / Q000737:chemistry / Q000378:metabolism; D010944:Plants / Q000737:chemistry / Q000378:metabolism*; D006109:Poaceae / Q000737:chemistry / Q000378:metabolism; D011834:Radiation Monitoring; D011847:Radioactive Fallout / Q000032:analysis; D012621:Seasons; D012987:Soil / Q000737:chemistry*; D012990:Soil Pollutants, Radioactive / Q000032:analysis / Q000378:metabolism; D013045:Species Specificity; D013997:Time Factors
chemical_list: D002588:Cesium Radioisotopes; D011847:Radioactive Fallout; D012987:Soil; D012990:Soil Pollutants, Radioactive