Hanoi University of Mining and Geology, No 18, Vien Street, Bac Tu Liem District, Hanoi, Viet Nam.
Institute of Research and Development, Duy Tan University, Danang, 550000, Viet Nam.
Chemosphere. 2021 May;270:128671. doi: 10.1016/j.chemosphere.2020.128671. Epub 2020 Oct 28.
Ra, U, K, and Th (Ra) activity concentrations of 61 soil samples distributed surrounding the rare earth element mine (NORM), MH, Lao Cai, Vietnam have been measured by HPGe detector. The activity concentrations of Ra, U, K, and Th (Ra) range from 1179 to 6291 Bq/kg, from 1024 to 8351 Bq/kg, from 260 to 3519 Bq/kg, and from 1476 to 35546 Bq/kg in the ore body and from 21.3 to 964 Bq/kg, from 23.4 to 1635 Bq/kg, from 124 to 3788 Bq/kg, and from 40.9 to 6107 Bq/kg outside the ore body in respective. The study area is considered as the high local natural background radiation with the concentration of Ra, U, K, and Th (Ra) of 156, 254, 647, and 908 Bq/kg in respective. Regarding the spatial distribution, the measured radionuclide concentrations are independent of the distance from measured points to the ore body. With regard to the hazard indices, the average calculated radiological hazard indices, including absorbed gamma dose rate, effective dose equivalent, and excess lifetime cancer risk significantly exceed the global average values. There is a disequilibrium between U/Ra concentrations in studied soil samples. The results also found that the Th (Ra) concentration and total absorbed gamma dose rate show a strong positive correlation (coefficient of determination, R = 1).
对越南老街省奠边府稀土元素矿（NORM）周围 61 个土壤样本的 Ra、U、K 和 Th（Ra）活性浓度进行了测量，使用 HPGe 探测器。矿体中 Ra、U、K 和 Th（Ra）的活性浓度范围为 1179 至 6291 Bq/kg、1024 至 8351 Bq/kg、260 至 3519 Bq/kg 和 1476 至 35546 Bq/kg，而矿体外的 Ra、U、K 和 Th（Ra）的活性浓度范围分别为 21.3 至 964 Bq/kg、23.4 至 1635 Bq/kg、124 至 3788 Bq/kg 和 40.9 至 6107 Bq/kg。研究区域被认为是高局部天然本底辐射区域，Ra、U、K 和 Th（Ra）的浓度分别为 156、254、647 和 908 Bq/kg。就空间分布而言，所测量的放射性核素浓度与测量点距矿体的距离无关。就危害指数而言，计算得出的平均辐射危害指数，包括吸收伽马剂量率、有效剂量当量和过量寿命癌症风险，显著超过全球平均值。在所研究的土壤样本中，U/Ra 浓度存在不平衡。结果还发现，Th（Ra）浓度和总吸收伽马剂量率之间存在很强的正相关关系（决定系数 R=1）。
