贵州赫章含煤岩系地层放射性水平调查

Investigation of Radioactive Level of Coal-bearing Strata in Hezhang,Guizhou Province,China

选取贵州赫章含煤岩系地层为研究对象,研究γ辐射剂量率、土壤氡气析出率,原煤、煤渣、土壤和水体(238U、232Th、226Ra、40K)的分布特征。结果表明,研究区γ辐射剂量率为43.10~323.24 nGy/h,小于520 nGy/h;原煤、煤渣和土壤的最大外照射指数Iγ分别为0.65、0.74和0.82,均未超过剂量限值1;赫章达依乡和六曲乡土壤氡浓度平均值分别为6 810 Bq/m^3和7 150 Bq/m^3,绝大多数小于20 000 Bq/m^3;区内含煤岩系地层的放射性核素和土壤氡析出率对环境影响较小。赫章含煤岩系地层原煤、煤渣和土壤样品中放射性核素238U、232Th、226Ra、40K多数低于贵州省土壤放射性核素背景值和我国土壤放射性核素背景值。通过单因子指数法对研究区放射性水平进行评价,多属无污染状态,水体放射性水平多数低于我国自来水标准。

Distribution characteristics of gamma radiation dose rate, gas release rate of radon in soil, and 238U, 232Th,226Ra and 4~K in coal, 0cinder, soil and water were studied in the coal-bearing strata in Hezhang, Guizhou Province. Results show that the dose of gamma radiation ranges from 43.10 to 323.24 nGy/h, lower than 520 nGy/h. The maximum external radiation index Iγ of coal, cinder and soil are O. 65, 0.74 and O. 82 respectively. The average radon concentrations in two villages of Hezhang are 6 810 Bq/m3 and 7 150 Bq/m3 , respectively and the majority is lower than 20 000 Bq/m3.The radion nuclides and soil radon exhalation rate have little effect on the environment. The radion nuclides23Su,232Th,226Ra, and 40K in coal, cinder and soil samples in Hezhang coal-bearing strata are lower than those in Guizhou Province and the background values of soil radion nuclides in China. The radioactive pollution level of the study area was evaluated by single factor index method, and the results are mostly pollution-free. Most of the radioactivity in water is lower than the standard of tap water in China.