首都圈土壤气中氡环境地球化学特征

Radon environmental geochemistry in soil gas around the Capital area of China

空气中的氡大部分源于岩石和土壤氡的释放。本研究对首都圈的三河地区、延怀盆地和唐山地区土壤气中氡浓度进行检测,分析其环境地球化学特征。结果表明,所调查土壤气中氡浓度三河地区最高,平均值在2×104～2.5×104Bq·m-3,唐山地区其次,平均值在1.5×104～2×104Bq·m-3,延怀盆地最低,平均值<1.5×104Bq·m-3,整体呈现研究区的东部土壤气中氡浓度高于西部地区。根据对研究区内土壤氡浓度的环境危害分类,局部达到中等风险等级;根据国家标准,在三河地区和唐山地区,局部需要采取建筑物底层地面抗开裂措施和一级防水措施,延怀盆地基本不需要采取防氡措施。

Radon in the air is mainly released from the rock and soil radon. The geochemical characteristics of radon in soil gas around the Capital area of China were investigated based on the measurements of radon concentrations in Sanhe area,Yanhuai basin and Tangshan area. The mean radon concentrations were 2 × 10^4- 2. 5 × 10^4,1.5 ×10^4- 2 × 10^4,and less than 1.5 ×10^4Bq·m^- 3in Sanhe area,Tangshan area,and Yanhuai basin,respectively. Overall,the distribution of radon concentration was higher in the east than in the west. Based on the soil radon concentration in the international environmental hazard classification,some parts of the study areas reached to the moderate risk level. Based on China＇s standards（ code for indoor environmental pollution control of civil building engineering）,anti-cracking and waterproof measures should be taken on the ground floors of buildings in Sanhe area and Tangshan area,while no measures are needed to prevent radon in Yanhuai basin.