The Red River is one of the largest rivers that plays an important role in the economic development of North Vietnam. There are many radionuclides bearing rare earth, uranium ore mines, mining industrial zones and magma intrusive formations along this river. The contamination and accumulation of radionuclides could exist at high concentration in surface sediments of this river. Thus, the present investigation aims to study the activity concentrations of ²²⁶Ra, ²³²Th (²²⁸Ra), ⁴⁰K, and ¹³⁷Cs in Red River surface sediments. Thirty sediment samples were collected, and their activity concentration was calculated using high-purity germanium gamma-ray detector. The observed results ranged from 51.0 ± 2.1 to 73.6 ± 3.7 for ²²⁶Ra, 71.4 ± 3.6 to 103 ± 5.2 for ²³²Th, 507 ± 24.0 to 846 ± 42.3 for ⁴⁰K, and ND (not detected) to 1.33 ± 0.06 Bq/kg for ¹³⁷Cs, respectively. In general, the natural radionuclides concentration of ²²⁶Ra, ²³²Th (²²⁸Ra), and ⁴⁰K is higher than the average world average values. This indicated that the natural radionuclides could contribute from similar and principal sources surrounding the upstream of Lao Cai where distributed uranium ore mines, radionuclide bearing rare earth mines, mining industrial zones and intrusive formations. Regarding the radiological hazard assessment, results of the indices computed such as absorbed gamma dose rate (D), the excess lifetime cancer risk (ELCR), and the annual effective dose equivalent (AEDE) were nearly two times higher than world average values.

红河是最大的河流之一，在北越的经济发展中发挥着重要作用。沿河分布着许多含有放射性核素的稀土矿、铀矿、采矿工业区和岩浆侵入地层。该河表层沉积物中可能存在高浓度的放射性核素污染和积累。因此，本次调查旨在研究红河表层沉积物中²²⁶ Ra、²³² Th ( ²²⁸ Ra)、⁴⁰ K 和^{137 Cs 的活度浓度。}采集沉积物样品30个，利用高纯锗γ射线检测器计算其活度浓度。观察到的结果范围为：²²⁶ Ra 为 51.0 ± 2.1 至 73.6 ± 3.7，232 Th 为 71.4 ± 3.6 至 103 ± 5.2，40 K 为⁵⁰⁷ ± 24.0 至 846 ± 42.3 ^， ND（未检测到）至 1.33 ± 0.06 Bq/ ¹³⁷ Cs 分别为 kg 。^{总体而言， 226} Ra、²³² Th（²²⁸ Ra）和⁴⁰ K天然放射性核素浓度高于世界平均水平。这表明天然放射性核素可能来自老街上游周围的相似且主要来源，那里分布着铀矿、含放射性核素的稀土矿、采矿工业区和侵入岩层。在放射危害评估方面，吸收伽马剂量率（D）、超额终生癌症风险（ELCR）、年有效剂量当量（AEDE）等指标计算结果比世界平均水平高出近两倍。