Professor Yuichi Onda of the Life and Environment Department of Tsukuba University, Professor Ryo Tateyamashiki of the Graduate School of Comprehensive Survival, Kyoto University, and a research group in Fukushima Prefecture have joined the river in the Abukuma River system in Fukushima Prefecture after the accident at the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Company. A follow-up study of the radioactive cesium concentration revealed that the concentration was significantly reduced in the basin affected by human activity.
According to the University of Tsukuba and Kyoto University, the research group analyzed long-term monitored data at 30 locations in the Abukuma River system.As a result, it was found that the cesium concentration decreased rapidly in one year after the accident and then continued to decrease gradually.
By the fifth year after the accident, the cesium concentration had dropped from one-third to one-twentieth of that of the Prichapi River after the Chernobyl nuclear power plant accident in the former Soviet Union, and environmental purification was carried out at a faster pace than the findings obtained in Europe. It will be progressing.
It was also revealed that the main sources of early radioactive cesium were paddy fields, cultivated land, and urban areas, which occupy 38% of the Abukuma River basin, and that cesium, which accounts for 85% of the total emission, is released from here.The research group believes that human activities are promoting purification, as there are many land-use forms such as paddy fields and urban areas where human activities have a large impact on the basins where the concentration has decreased significantly.After the third year after the accident, the effects of decontamination were confirmed at some points.
The results of this research are expected to be useful in formulating a recovery plan from possible radioactive contamination accidents in the future.
