Regassa Tadele Negash, Raba Gelana Amente, Kpeglo David Okoh
Ethiopian Technology Authority-ETA (Formerly ERPA), P.O. Box 20486, Addis Ababa, Ethiopia.
Department of Physics, College of Natural and Computational Sciences, Haramaya University, P.O. Box 138, Haramaya, Ethiopia.
Environ Monit Assess. 2024 Dec 27;197(1):107. doi: 10.1007/s10661-024-13568-0.
Excavation of terrestrial surface of the Earth could enhance the chance of exposure to radon while gases in the underground get access to escape. This study was aimed to assess the level of radon concentration from soil samples of quarrying sites at Hakim Gara in Ethiopia using CR-39 detectors in sealed container technique. The results of the measured radon concentration level were ranging from 164.3 to 494.0 Bq/m with average value of 295.7 ± 87.09 Bq.m. The activity concentration value of radium ranging from 0.63 to 2.74 Bq.kg with average value of 1.59 ± 0.55 Bq.kg. The radon surface exhalation rate ranging between 0.95 to 4.1 Bqm h with mean value of 2.38 ± 0.83 Bqm h. The mass exhalation rate ranging between 0.01 and 0.11 Bqkg h with average 0.06 ± 0.03 Bqkg h. The AED and ELCR values for the study area were calculated and the mean value of the quarry area were determined on the basis of altitude variation and found to be different for individual and group sample locations. Compared to values recommended by WHO for outdoor radon exposure, the measured levels of radon concentration were observed to be higher in the study area. But residential areas under construction in the area need further studies since the measured and calculated values were high for indoors in some soil samples.
挖掘地球陆地表面会增加氡暴露的机会，因为地下气体有机会逸出。本研究旨在使用密封容器技术中的CR - 39探测器，评估埃塞俄比亚哈吉姆加拉采石场土壤样本中的氡浓度水平。测得的氡浓度水平范围为164.3至494.0 Bq/m，平均值为295.7±87.09 Bq·m。镭的活度浓度值范围为0.63至2.74 Bq·kg，平均值为1.59±0.55 Bq·kg。氡表面析出率范围在0.95至4.1 Bq·m²·h之间，平均值为2.38±0.83 Bq·m²·h。质量析出率范围在0.01至0.11 Bq·kg⁻¹·h之间，平均为0.06±0.03 Bq·kg⁻¹·h。计算了研究区域的年有效剂量（AED）和平衡当量浓度（ELCR）值，并根据海拔变化确定了采石场区域的平均值，发现个体和组样本位置的平均值有所不同。与世界卫生组织推荐的室外氡暴露值相比，研究区域测得的氡浓度水平较高。但该地区正在建设的居民区需要进一步研究，因为在一些土壤样本中，室内的测量值和计算值都很高。
