【摘要】 采集了甘肃西北地区（酒泉市和嘉峪关市）10个表层土壤，采用高分辨电感耦合等离子体质谱仪（HR-ICP-MS）测量土壤中^239+240Pu活度浓度和²⁴⁰Pu/²³⁹Pu原子比值。结果表明，^239+240Pu的活度浓度范围为0.072～0.202 Bq/kg,平均值为（0.114±0.039） Bq/kg,与全国表层土壤中钚活度浓度（0.01～0.83 Bq/kg）处于同一水平。²⁴⁰Pu/²³⁹Pu原子比范围为0.150～0.245,平均值为（0.200±0.025）,处于全球大气钚沉降的²⁴⁰Pu/²³⁹Pu比值平均值0.10～0.35范围内，初步判断，甘肃西北地区表层土壤中钚主要来源于全球大气钚沉降。更多还原

【Abstract】 Ten topsoils in northwest of Gansu provine（Jiuquan city and Jiayuguan city） were collected, and high resolution inductively coupled plasma mass spectrometry（HR-ICP-MS） was used to measure the activity concentration of ^239+240Pu and the atomic ratio of ²⁴⁰Pu/²³⁹Pu in the soil. The results showed that the activity concentration of ^239+240Pu ranged from 0.072 to 0.202 Bq/kg, with an average value of（0.114±0.039） Bq/kg, which was at the same level as the plutonium activity concentration in the topsoil of China（0.01 to 0.83 Bq/kg）. The atomic ratio of ²⁴⁰Pu/²³⁹Pu ranged from 0.150 to 0.245, with an average value of（0.200±0.025）, which was in the range of the average ²⁴⁰Pu/²³⁹Pu ratio of global atmospheric plutonium deposition from 0.10 to 0.35. It was preliminarily judged that the plutonium in the topsoil of northwest of Gansu province mainly came from the world atmospheric plutonium deposition.更多还原