A large amount of radioactivity was released into the environment after the Fukushima nuclear accident （FNA） in Japan in 2011. This radioactivity had a significant impact on the global environment, and there was muc...A large amount of radioactivity was released into the environment after the Fukushima nuclear accident （FNA） in Japan in 2011. This radioactivity had a significant impact on the global environment, and there was much public concern about its effects. The subsequent assessment of the FNA and the environmental remediation required are proving to be long and complicated tasks. The assessments are based on the radioactive source terms for the FNA, which determine the level of damage caused by the nuclear accident. We investigated the radioactive source terms from three aspects： the amount and composition of the radionuclides; the activity and atomic ratio of the radionuclides; and comparison with other historical events. The total amount of radioactivity, excluding the radioactive noble gases （85Kr and 133Xe）, released by the FNA was about 10% of that released by the Chernobyl nuclear accident in 1986 and 〈1%o of the global fallout from the atmosphere nuclear explosion. However, the FNA was the most serious nuclear accident in terms of radioactive pollution of the marine environment. The recovery actions carried out after the FNA have been evaluated and the environmental impacts of the FNA are discussed.展开更多
Evaluation of soil erosion in agricultural fields is valuable to develop conservation practices for reducing agricultural nonpoint source pollution. Soil erosion rates were quantified using the fallout radionuclide tr...Evaluation of soil erosion in agricultural fields is valuable to develop conservation practices for reducing agricultural nonpoint source pollution. Soil erosion rates were quantified using the fallout radionuclide tracer technique in Mojiagou Basin located on the outskirts of Changchun in Northeast China. The calculated soft erosion rates in the study area were 1.99 and 1.85 mm year-1 using 137Cs and excess 210pb （210Pbex） measurements, respectively. Both fallout radionuclides showed a similar tendency at downslope sites. All measured sites have experienced net erosion during the past 50 to 100 years. 137Cs and 210Pbex measurements were useful to quantify soil erosion rates on field and small basin scales. At this rate of erosion, the current fertile topsoil layer would be entirely removed within 70 years.展开更多
基金China Polar Science Strategy Foundation(Grant No.20120316)Tsinghua University Initiative Scientific Research Program(Grant No.20111080965)the National Natural Science Foundation of China(Grant Nos.11205094&41106167)
文摘A large amount of radioactivity was released into the environment after the Fukushima nuclear accident （FNA） in Japan in 2011. This radioactivity had a significant impact on the global environment, and there was much public concern about its effects. The subsequent assessment of the FNA and the environmental remediation required are proving to be long and complicated tasks. The assessments are based on the radioactive source terms for the FNA, which determine the level of damage caused by the nuclear accident. We investigated the radioactive source terms from three aspects： the amount and composition of the radionuclides; the activity and atomic ratio of the radionuclides; and comparison with other historical events. The total amount of radioactivity, excluding the radioactive noble gases （85Kr and 133Xe）, released by the FNA was about 10% of that released by the Chernobyl nuclear accident in 1986 and 〈1%o of the global fallout from the atmosphere nuclear explosion. However, the FNA was the most serious nuclear accident in terms of radioactive pollution of the marine environment. The recovery actions carried out after the FNA have been evaluated and the environmental impacts of the FNA are discussed.
基金Supported by the National Basic Research Program(973 Program)of China(No.2007CB407205)the Knowledge Innovation Program of the Chinese Academy of Sciences(No.KSCX1-YW-09-13)+1 种基金the National Key Technology R&D Program of China during the 12th Five-Year Plan Period(No.2011BAD31B00)the National Major Science and Technology Program of China for Water Pollution Control and Treatment(No.009ZX07106-03-01)
文摘Evaluation of soil erosion in agricultural fields is valuable to develop conservation practices for reducing agricultural nonpoint source pollution. Soil erosion rates were quantified using the fallout radionuclide tracer technique in Mojiagou Basin located on the outskirts of Changchun in Northeast China. The calculated soft erosion rates in the study area were 1.99 and 1.85 mm year-1 using 137Cs and excess 210pb （210Pbex） measurements, respectively. Both fallout radionuclides showed a similar tendency at downslope sites. All measured sites have experienced net erosion during the past 50 to 100 years. 137Cs and 210Pbex measurements were useful to quantify soil erosion rates on field and small basin scales. At this rate of erosion, the current fertile topsoil layer would be entirely removed within 70 years.
