【作者】 卜文庭； 郭秋菊；

【Author】 BU Wen-ting,GUO Qiu-ju (School of Physics,Peking University,Beijing 100871,China)

【机构】 北京大学物理学院；

【摘要】 钚（Plutonium,Pu）具有极强的化学毒性和放射性,能对人体健康造成危害,其在环境中的含量与行为是评价人类核活动对环境影响的重要内容。随着人们关注度的提高和测量方法的改进,近年来有关我国土壤中Pu的含量与分布水平的信息得到了很大的扩展。我国表层土壤不同区域Pu含量有较大差异,总体来讲^239+240Pu比活度均在1mBq/g以下。新疆核试验场上风向地区已有成果表明Pu来源于全球大气沉降,没有受到我国核试验的影响,而下风向地区有采样点表明^239+240Pu沉积通量达到了同纬度全球沉降值的5倍以上（>300Bq/m²）,但由于报道数据有限,尚不能全面评价我国核试验对下风向地区的影响大小和影响范围。我国核试验场周边以外地区Pu沉积通量均在全球沉降范围以内（10-60Bq/m²）,²⁴⁰Pu/²³⁹Pu比值也与全球沉降比值（0.18）没有显著差异。Pu在不同类型的土壤中呈现出不同的分布形式,其迁移行为受到土壤类型、气候条件等多种因素的影响。更多还原

【Abstract】 Plutonium（Pu）isotopes,being characterized as strong chemical and radiological toxicity,are high risky for human health,and study on Pu concentrations and distributions is an important part for environmental assessment of human nuclear activity.The information of Pu in the soils of China has been expanded benefiting from the improvement of measuring methods and the increasing scientific and public concern in recent years.The activity of ^239+240pu in surface soils from different areas of China varies,but typically less than 1mBq/g.It was indicated by prophase results that no influence from Chinese Nuclear Test Site（CNTS）to the upwind areas of that was observed.However,the Pu inventory of some points from downwind areas of CNTS is five times higher than that of global fallout,which was suggested to be the influence of CNTS.Further field investigations in detail are necessary to master the total figure of CNTS.For the areas far away from CNTS,Pu inventory and ²⁴⁰Pu/²³⁹Pu are both similar with global fallout.The forms of Pu vertical distribution vary for different soils,depending upon various factors（e.g.soil type,weather condition）.更多还原