Upadhyay Devendra Raj, Phuyal Anish, Tajudin Suffian Mohamad, Khanal Raju
Central Department of Physics, Tribhuvan University, Kirtipur, Kathmandu, Nepal.
Department of Physics, Amrit Campus, Tribhuvan University, Kathmandu, Nepal.
Heliyon. 2024 May 10;10(10):e30822. doi: 10.1016/j.heliyon.2024.e30822. eCollection 2024 May 30.
The evaluation of primordial radionuclide concentrations in rapidly urbanized and concrete-laden areas through the importation of construction materials from various regions of Nepal is both important and essential. This study utilized a portable gamma-ray spectrometer (PGIS 2) to analyze the distribution of three natural radionuclides: uranium (U), thorium (Th), and potassium (K) in Tarakeshwor Municipality, Kathmandu, Nepal. The measured dose rates ranged from 70.22 nSv hr to 163.66 nSv hr, with an average of 124.65±20.29 nSv hr, surpassing the global average of 59 nSv hr. The activity concentrations of K, U, and Th exceeded global averages, indicating relatively higher natural radioactivity concentrations in the region. Specifically, the average values for K, U, and Th were 935.26±172.30 Bq kg, 80.47±15.53 Bq kg, and 80.44±18.58 Bq kg, respectively. The calculated radium equivalent () ranged from 132.26 to 351.22 Bq kg, and the annual gonadal equivalent dose () varied from 372.61 to 1028.81 Sv yr. The annual effective dose rates for indoor and outdoor environments were 0.54±0.09 mSv yr and 0.15±0.03 mSv yr, respectively, both exceeding the global average. The representative level index () within the study area averaged 1.96±0.32, indicating an elevated radiation risk. The excess lifetime cancer risk () values for outdoor and indoor environments were 0.52 ±0.09 and 1.87 ±0.31, respectively, surpassing the world average. Additionally, external hazard indices () ranged from 0.36 to 0.59, while internal hazard indices () ranged from 0.38 to 1.20, both indicating values higher than UNSCEAR recommendations. These findings underscore the necessity for further experimental analysis employing ex-situ equipment. The data generated in this study can provide a valuable baseline for future assessments and interventions in radiation risk management guidelines within the country.
通过从尼泊尔不同地区进口建筑材料来评估快速城市化且混凝土密布地区的原生放射性核素浓度，这一工作既重要又必要。本研究利用便携式伽马射线光谱仪（PGIS 2）分析了尼泊尔加德满都塔拉凯什沃市三种天然放射性核素：铀（U）、钍（Th）和钾（K）的分布情况。测量得到的剂量率范围为70.22纳希沃特/小时至163.66纳希沃特/小时，平均为124.65±20.29纳希沃特/小时，超过了59纳希沃特/小时的全球平均值。钾、铀和钍的活度浓度超过了全球平均值，表明该地区天然放射性浓度相对较高。具体而言，钾、铀和钍的平均值分别为935.26±172.30贝克勒尔/千克、80.47±15.53贝克勒尔/千克和80.44±18.58贝克勒尔/千克。计算得到的镭当量（）范围为132.26至351.22贝克勒尔/千克，年性腺当量剂量（）范围为372.61至1028.81希沃特/年。室内和室外环境的年有效剂量率分别为0.54±0.09毫希沃特/年和0.15±0.03毫希沃特/年，均超过了全球平均值。研究区域内的代表性水平指数（）平均为1.96±0.32，表明辐射风险有所升高。室外和室内环境的超额终生癌症风险（）值分别为0.52±0.09和1.87±0.31，均超过了世界平均值。此外，外部危险指数（）范围为0.36至0.59，而内部危险指数（）范围为0.38至1.20，两者均表明数值高于联合国原子辐射效应科学委员会的建议值。这些发现强调了采用异地设备进行进一步实验分析的必要性。本研究生成的数据可为该国未来辐射风险管理指南的评估和干预提供有价值的基线。
