闽北570铀矿区周围大气环境氡浓度水平研究

对闽北570铀矿区的大气氡环境地球化学进行了研究。矿区废渣和坑道口释放出来的氡气对周围大气形成了一定的氡污染,特别是在矿区周围0.5～1km范围内的污染较严重。但是空气中的氡污染随着离矿区的距离增大而迅速减弱,矿区周围居民室内氡的浓度较高,是福建省室内氡浓度平均值的1～8倍左右。在进行调查的28个居室中,有6个(占21%)居室内氡浓度超过我国住房内氡浓度控制标准GB/T16146-1995中已建住房的室内氡浓度上限值(200Bq/m3)和国际辐射防护委员会制定的200Bq/m3的上限值。居室中氡浓度的升高,除了受矿区释放出来的氡污染外,还因为本地区属高本底辐射区,房基下的土壤、岩石和建筑材料中的铀、镭等放射性元素的含量高,其放射性衰变产生的氡释放出来进入室内。

ATMOSPHERIC RADON IN NO.570 URANIUM DEPOSIT AREA,NORTH FUJIANG PROVINCE

Environmental geochemistry of radon in the No. 570 uranium deposit area, North Fujian Province, shows that the air within the bounds of 0.5～1km around this area has been seriously contaminated by radon released during uranium exploitation and mining, but the contamination level of radon tends to rapidly reduce with increasing distance away from this (area.) The indoor radon concentrations in this area are high, about 1～8 times the average value reported from Fujian Province. Of all the 28 dwellings surveyed, 6 dwellings (21%) have indoor radon levels above 200 Bq/m~3, a limit value of indoor radon laid down by China Environmental Protection Agency. The main reason for the high indoor radon concentrations is that this area belongs to a high background radiation area, so the soil and rocks in house basement have high contents of U and Ra with an amount of radon produced.