13:45 〜 15:15
[MAG34-P05] 大気放射性セシウムの植物による吸収とその全体に占める寄与
キーワード：放射性セシウム、大気、植物吸収
Absorption of radio-cesium as 137Cs by plants is interested for the understanding of its translation in the environment and for the risk assessment in the agriculture.
Our group has been observed the atmospheric activity concentration of 137Cs increased in heavily polluted areas in Fukushima, and found the concentration increased in summer, and its major career particle is supposed to be bioaerosols, especially fungal spores, emitted from the surrounding vegetation. In this study, possibility of radio-cesium absorption by vegetation (herbaceous plants) from the atmosphere (aerosol particles), and evaluation of its contribution in the total radio-cesium absorption including absorption from soil and litter.
Experiment 1:
The aerosol samples were collected on quartz fiber filters with high-volume air samplers at heavily-polluted area in Fukushima. Water solubility of 137Cs in the sample aerosol was measured by pure-water extracting experiment, and 50-70% of 137Cs in the aerosols is water-soluble in summertime samples obtained between July and September. 48-hour hydroponics experiment of rice was conducted by using solution obtained the water-extracting experiment, and almost all of 137Cs extracted was absorbed/adsorbed with the rice in the summertime samples. These results indicated that major part of the aerosol 137Cs in summertime can be absorbed by the vegetation via water.
Experiment 2
In order to evaluate the contribution of absorption from the atmosphere (aerosol) in the total radio-cesium absorption by plants including absorption from soil and litter, some herbaceous plants were cultivated in a field in the polluted area site in Fukushima from May to September, 2022. They cultivated in 9 blocks of higher and less contaminated soils with/without litter inside/outside of forest. 137Cs concentration in soil in each block and those in litter added into 3 blocks were measured with Ge detector. Rain water inside/outside of forest were collected and 137Cs deposition flux was measured. Aerosol was also sampled near cultivation experiment blocks and soluble 137Cs concentration was measured by the water extraction experiment. By applying multiple regression analysis, contribution of soil, litter, rain, and atmospheric in the 137Cs absorbed by cultivated herbaceous plants. Outside of forest, about 90% of 137Cs was absorbed from soil including humus, and contribution of the atmosphere including rain was less than 10%. More than 60% of 137Cs was absorbed from throughfall in forest.
Our group has been observed the atmospheric activity concentration of 137Cs increased in heavily polluted areas in Fukushima, and found the concentration increased in summer, and its major career particle is supposed to be bioaerosols, especially fungal spores, emitted from the surrounding vegetation. In this study, possibility of radio-cesium absorption by vegetation (herbaceous plants) from the atmosphere (aerosol particles), and evaluation of its contribution in the total radio-cesium absorption including absorption from soil and litter.
Experiment 1:
The aerosol samples were collected on quartz fiber filters with high-volume air samplers at heavily-polluted area in Fukushima. Water solubility of 137Cs in the sample aerosol was measured by pure-water extracting experiment, and 50-70% of 137Cs in the aerosols is water-soluble in summertime samples obtained between July and September. 48-hour hydroponics experiment of rice was conducted by using solution obtained the water-extracting experiment, and almost all of 137Cs extracted was absorbed/adsorbed with the rice in the summertime samples. These results indicated that major part of the aerosol 137Cs in summertime can be absorbed by the vegetation via water.
Experiment 2
In order to evaluate the contribution of absorption from the atmosphere (aerosol) in the total radio-cesium absorption by plants including absorption from soil and litter, some herbaceous plants were cultivated in a field in the polluted area site in Fukushima from May to September, 2022. They cultivated in 9 blocks of higher and less contaminated soils with/without litter inside/outside of forest. 137Cs concentration in soil in each block and those in litter added into 3 blocks were measured with Ge detector. Rain water inside/outside of forest were collected and 137Cs deposition flux was measured. Aerosol was also sampled near cultivation experiment blocks and soluble 137Cs concentration was measured by the water extraction experiment. By applying multiple regression analysis, contribution of soil, litter, rain, and atmospheric in the 137Cs absorbed by cultivated herbaceous plants. Outside of forest, about 90% of 137Cs was absorbed from soil including humus, and contribution of the atmosphere including rain was less than 10%. More than 60% of 137Cs was absorbed from throughfall in forest.