摘要
临沧盆地受其基底花岗岩的影响,环境中存在天然放射性水平异常。本文测得其土壤中放射性核素226Ra、238U、232Th和40K的比活度分别为53.4(38.7-62.8)、161.2(127.3-211.7)、120.9(106.5-140.6)和632.2(521.7-707.5)Bq/kg,明显高于全国和世界平均值。花岗岩天然放射性水平较高,与土壤放射性有一定的相关性,为土壤伴生放射性提供了较好的来源。采用测得的土壤放射性核素226Ra、232Th和40K的比活度,计算了距地面1m高处空气中γ辐射吸收剂量率和年有效剂量率,并对γ辐射外照射水平进行了评价。评价结果表明,虽然该区的空气吸收剂量率较高,但是年有效剂量率在容许范围之内。因此该区属于外照射水平的安全区域,人居环境不受影响。
In Lincang basin,influenced by the granite,the level of natural radioactivity in the environment is relatively high.This work deals with the determination of natural radioactivity of soil in this area.The activity concentrations for 226Ra、238U、232Th and 40K obtained were obviously greater than the average value both countrywide and worldwide,which were 53.4(from 38.7 to 62.8),161.2(from 127.3 to 211.7),120.9(from 106.5 to 140.6)and 632.2(from 521.7 to 707.5)Bq/kg.The level of natural radioactivity of the granite was relatively high,and because having certain relevance with soil,it provided accompanying radioactivity of soil with good source.To assess the radiological hazard of the natural radioactivity in soil,the absorbed dose rate and annual effective dose rate were calculated.The results show that,although the absorbed dose rate in the study area is a little higher,the annual effective dose rate is lower than the recommended value.So Lincang basin is safe in radiological level and the dwelling environment is not affected.
出处
《中国人口·资源与环境》
CSSCI
北大核心
2011年第S1期90-92,共3页
China Population,Resources and Environment
