Isotope-geochemical characteristics of groundwater in the southern part of Western Siberia and factors controlling uranium mobilization

IF 5.8 Q2 ENGINEERING, ENVIRONMENTAL

Groundwater for Sustainable Development Pub Date : 2026-08-01 Epub Date: 2026-07-30 DOI:10.1016/j.gsd.2026.101674

D.A. Novikov, A.N. Pyryaev, F.F. Dultsev, L.G. Vakulenko, N.I. Yandola, A.A. Khvashevskaya, Y.V. Fomina

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引用次数: 0

Abstract

This study presents integrated isotope-geochemical data on groundwater from the southern part of Western Siberia to identify the factors of uranium mobilization. Groundwater within the multi-aged, complex rock aquifer system is predominantly of HCO₃–Mg–Ca type, whereas waters hosted in granitoid units (the Priobsky and Barlak complexes) exhibit SO₄–HCO₃–Na–Mg–Ca characteristics. Measured ²²²Rn activity ranges from 1 to 1161 Bq/L. This study systematically evaluated the disequilibrium state of uranium isotopes (²³⁴U/²³⁸U) across contrasting hydrogeological settings: granitoid massifs, contact zones, and sedimentary complexes of different ages. Maximum ²³⁴U excess occurs in granitoid-hosted groundwater, confirming the Priobsky and Barlak complexes as the primary uranium sources in the region. Stable isotope signatures (δ²H, δ¹⁸O) confirm the meteoric origin of the groundwater, with recharge of the Paleozoic bedrock aquifer complex being unaffected by short-term seasonal variations. Thermodynamic modeling classifies all studied waters as a single geochemical type: siliceous-Na (Ca–Mg–K). Elevated uranium concentrations are directly linked to granitoid lithologies hosting accessory minerals (e.g., uraninite, monazite, zircon, bastnäsite) that accumulate uranium, thorium, and rare earth elements. Radionuclides are released into groundwater as a result of mineral weathering. Under oxidizing conditions, uranium remains mobile in the form of uranyl ion (UO₂²⁺), whereas thorium is immobilized via adsorption onto mineral surfaces or precipitation. Subsequent uranium precipitation at redox boundaries may contribute to the formation of paleovalley-type infiltration uranium deposits. These findings advance the understanding of uranium mobilization pathways and support targeted assessments of groundwater safety and mineral potential in crystalline terrains.

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西西伯利亚南部地下水同位素地球化学特征及铀运移控制因素

本文利用西西伯利亚南部地下水同位素地球化学综合资料，探讨了铀的运移因素。多年龄复杂岩石含水层系统中的地下水以HCO3-Mg-Ca型为主，而花岗岩单元（Priobsky和Barlak杂岩）中的水则表现出SO4-HCO3-Na-Mg-Ca的特征。测得的222Rn活度范围为1至1161 Bq/L。本研究系统地评估了不同水文地质背景下铀同位素（234U/238U）的不平衡状态：花岗岩块体、接触带和不同年龄的沉积复合体。最大的234U过量发生在花岗岩类地下水中，这证实了Priobsky和Barlak杂岩是该地区的主要铀源。稳定的同位素特征（δ2H, δ18O）证实了地下水的大气来源，古生代基岩含水层复合体的补给不受短期季节变化的影响。热力学模型将所有研究的水分类为单一的地球化学类型：硅-钠（Ca-Mg-K）。铀浓度升高与花岗岩岩性直接相关，花岗岩岩性含有辅助矿物（如铀矿、独居石、锆石、bastnäsite），这些矿物会积聚铀、钍和稀土元素。由于矿物风化，放射性核素被释放到地下水中。在氧化条件下，铀以铀酰离子（UO22+）的形式保持移动，而钍通过吸附在矿物表面或沉淀而固定。随后在氧化还原边界处的铀沉淀可能有助于古山谷型浸润铀矿床的形成。这些发现促进了对铀运移途径的理解，并支持有针对性地评估地下水安全和结晶地形的矿物潜力。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Groundwater for Sustainable Development Social Sciences-Geography, Planning and Development

CiteScore

11.50

自引率

10.20%

发文量

152

期刊介绍： Groundwater for Sustainable Development is directed to different stakeholders and professionals, including government and non-governmental organizations, international funding agencies, universities, public water institutions, public health and other public/private sector professionals, and other relevant institutions. It is aimed at professionals, academics and students in the fields of disciplines such as: groundwater and its connection to surface hydrology and environment, soil sciences, engineering, ecology, microbiology, atmospheric sciences, analytical chemistry, hydro-engineering, water technology, environmental ethics, economics, public health, policy, as well as social sciences, legal disciplines, or any other area connected with water issues. The objectives of this journal are to facilitate: • The improvement of effective and sustainable management of water resources across the globe. • The improvement of human access to groundwater resources in adequate quantity and good quality. • The meeting of the increasing demand for drinking and irrigation water needed for food security to contribute to a social and economically sound human development. • The creation of a global inter- and multidisciplinary platform and forum to improve our understanding of groundwater resources and to advocate their effective and sustainable management and protection against contamination. • Interdisciplinary information exchange and to stimulate scientific research in the fields of groundwater related sciences and social and health sciences required to achieve the United Nations Millennium Development Goals for sustainable development.