牦牛坪稀土矿区土壤天然放射性水平评价  

Evaluation of soil natural radioactive level in Maoniuping REE deposit

作　　者：张琮[1,2] 施泽明[1,3] 阚泽忠[4] 杨伟河[1] 张峻基 魏菲[1] 

机构地区：[1]成都理工大学核技术与自动化工程学院,成都610059 [2]平顶山市瑞平煤电有限公司德平热电厂,河南平顶山467000 [3]四川省地学核技术重点实验室,成都610059 [4]四川省地质调查院,成都610059

出　　处：《辐射防护》2015年第2期123-128,共6页Radiation Protection

基　　金：四川省地勘基金"四川省安宁河流域湖泊及矿山生态地球化学环境调查";四川高等学校科技创新重大培育项目"四川省西昌市邛海湖泊沉积速率及环境演化研究"

摘　　要：利用γ能谱仪对牦牛坪稀土矿区土壤的天然放射性核素进行了现场测量,计算了γ射线空气吸收剂量率和年有效剂量,并与白云鄂博稀土矿区以及广东下庄铀矿田进行对比。研究结果显示,该地区土壤中放射性核素238U、232Th和40K的含量,分别为52.36(5.55~201.06)Bq/kg、122.33(38.04~723.70)Bq/kg、1 010.09(125.20~1 705.85)Bq/kg;γ射线空气吸收剂量率平均值177.16 Gy/h,高于全国(81.50 n Gy/h)和世界(80.00 n Gy/h)的平均值,也高于白云鄂博稀土矿区(120.00 n Gy/h)以及广东下庄铀矿田(124.00 n Gy/h)的平均值。但γ外照射有效剂量在国家标准限量控制的范围内,因此,研究区天然放射性水平尚属正常范围内。该地区稀土的开采利用造成土壤天然放射性水平较高;大面积出露上三叠统冕西花岗岩体,导致研究区土壤的天然放射性水平高于白云鄂博稀土矿区以及广东下庄铀矿田。The natural radioactivities of radionuclides in the soil of Maoniuping REE deposit were measured using gamma ray spectroscopy with its internal and external exposure index,γ exposure rate and γ external exposure effective dose calculated accordingly and then compared with that of the Baiyun Obo rare earth mining area and Xiazhuang uranium ore field in Guangdong. Results show that the main value of γ exposure rate( 177. 16 Gy / h) is higher than the national reference value( 81. 50 n Gy / h),international reference value( 80. 00 n Gy / h),Baiyun Obo rare earth mining area reference value( 120. 00 n Gy /h) and Xiazhuang uranium ore field reference value( 124. 00 n Gy /h) in Guangdong as well. The natural radioactivity level of study area still lies within normal range because its internal and external exposure index,γ exposure rate and gamma external exposure effective dose are within the national referenced range. Rare earth mining contributes to the higher soil natural radioactivity level of the study area; Large area exposed in Triassic crown west granite rock mass in the study area also leads to a higher natural radioactivity level of soil than Baiyun Obo rare earth mining area and Xiazhuang uranium ore field in Guangdong.

关 键 词：能谱 γ射线空气吸收剂量率 年有效剂量 放射性水平 

分 类 号：X825[环境科学与工程—环境工程] X837