【摘要】 2011年3月11日,日本东北海域发生9.0级地震并引发海啸,受此影响日本福岛第一核电站发生核泄漏事故。3月26日,我国黑龙江监测站首次在空气样品中监测到来自日本福岛的放射性元素Ⅰ-131,监测持续近一个月。基于我国31个省(区、市)的大气放射性浓度监测记录,综合利用Hybrid Single-Particle Lagrangian Integrated Trajectory Model(HYSPLIT)模式的扩散轨迹模拟技术和大气环流形势,分析讨论了日本福岛核事故泄漏期间我国大气放射性环境水平。整个监测期间,我国Ⅰ-131的浓度最大值位于吉林省8.01 mBq·m~3,发生在4月7日左右,与在此期间我国东部地区的持续东风紧密相关;此外,华北、东北和西北的整体Ⅰ-13l相对浓度较高。Cs-137和Cs-134的最大值均发生在新疆地区,浓度分别为1.55和1.42mBq·m~3;与此同时,其全国平均浓度呈双峰型变化。峰值分别发生在4月4日和9日左右,其结果反映了大气环流和排放速率变化的综合影响。我国西北和华北的监测浓度值较高。此外,还就Cs-137/Ⅰ-131和Cs-134/Cs-137的比值与其他国家的监测结果进行了对比分析,结果表明,我国监测到的Cs-137/Ⅰ-13l比值在0.04~0.9之间,其值变化范围较大,且整体呈上升趋势,与此同时,整个监测期间Cs-134/Cs-l 37比值在l附近摆动。更多还原

【Abstract】 On March 11,2011,the Fukushima Daiichi Nuclear Power Plant was severely damaged by the massive 9.0 earthquakes and tsunami that struck off the northeast coast of the Island of Honshu.The damage to the nuclear facility has resulted in substantial environmental releases of radioactive materials into atmosphere.As a consequence,on March 26,the radioactive material Ⅰ-131 from Fukushima Daiichi nuclear accident（FDNA）was monitored in China’s Heilongjiang air sampling for the first time.The monitoring of FDNA in China lasted for nearly a month,till April 22,the radioactive substances monitored in China mainland,which are 1-131,Cs-137 and Cs-134,were close to basic values.Based on these monitoring data and HYSPLIT’s forward and backward trajectory modeling,this paper estimates the impacts of Fukushima Daiichi accident on China’s radioactivity levels.During the monitoring period,the maximum concentration of Ⅰ-131 which is located in Jilin Province,is 8.01 mBq·m³ and occurs in April 7.This value is closely related to the prevailing eastern winds during this period.Meanwhile,relatively high 1-131 concentration is monitored in North China,the Northeast and Northwest of China.For Cs-137 and Cs134,the maximum values both are found in the Xinjiang Region,being 1.55 and 1.42 mBq·m^-3,respectively around April 4 and 9.At the same time,the trend of national averaged concentration shows two peaks around.Northwest and North China are found to have higher concentration of Cs-137 and Cs-134. Additionally,the ratios of Cs-137/Ⅰ-131 and Cs-134/Cs-137 are analyzed and compared with the measurement results by other countries.The Cs-137/Ⅰ-131 activity ratios（0.04—0.9）are observed to increase with time as expected from radioactive decay,and Cs-134/Cs-137 activity ratio is measured near the line 1.0.更多还原