Scholarlink

<p>Daihai Lake, a typical closed inland lake in the arid and semi-arid region of Inner Mongolia, has been subject to two consecutive years of ecological water replenishment to mitigate its severe ecological degradation. While the lake water level has risen and wetland ecosystems have been gradually restored, existing studies have predominantly focused on changes in lake water quality, leaving a critical research gap regarding the hydrochemical evolution, formation mechanisms, and drinking water safety risks of groundwater in the plain area of the Daihai Lake Basin under the dynamic conditions of ongoing water replenishment. To fill this gap, this study systematically analyzed the hydrochemical characteristics and formation mechanisms of groundwater in the study area, and conducted a comprehensive groundwater quality assessment. A suite of representative groundwater samples were collected from the study area after two years of ecological water replenishment, and analyzed using an integrated set of methods including Self-Organizing Map (SOM) clustering, hydrochemical graphical analysis, ion ratio analysis, multivariate statistical analysis, and the Entropy-weighted Water Quality Index (EWQI) method. The results show that: (1) Groundwater is divided into three clusters via SOM, with distinct ion sources from carbonate/silicate weathering and halite dissolution across clusters; some samples have excess SO₄<sup>2−</sup> and HCO₃<sup>−</sup>, requiring additional cations for charge balance. (2) Groundwater evolution is jointly controlled by water-rock interaction and evaporative concentration, with limited influence from atmospheric precipitation. (3) Three high-fluoride enrichment mechanisms are identified: mineral dissolution under weakly alkaline conditions, evaporative concentration-driven F⁻ enrichment, and accelerated dissolution of fluorine-bearing minerals induced by acidic mining wastewater. (4) 89% of Cluster-3 groundwater meets drinking standards (EWQI &lt; 50), while 70% of groundwater samples from Cluster 1 and Cluster 2 are of poor quality, mainly distributed in the southwestern lakeshore. This study systematically elucidates the hydrochemical characteristics and formation mechanisms of groundwater in the Daihai Lake Basin under continuous ecological water replenishment, identifies key risk zones for groundwater quality, and provides a solid scientific basis for the protection and sustainable utilization of regional groundwater resources, as well as the optimization of ecological water replenishment strategies in similar arid and semi-arid inland lake basins.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Hydrochemical evolution and formation mechanisms of groundwater in the Daihai Lake Basin plain under ongoing ecological water replenishment

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2026年5月2日

查看全文
  • Juanjuan Zhang,
  • Lewei He,
  • Tengfei Ma,
  • Haozhong Yuan,
  • Wenxin Liu,
  • Liqun Sun,
  • Zihao Yan

摘要

Daihai Lake, a typical closed inland lake in the arid and semi-arid region of Inner Mongolia, has been subject to two consecutive years of ecological water replenishment to mitigate its severe ecological degradation. While the lake water level has risen and wetland ecosystems have been gradually restored, existing studies have predominantly focused on changes in lake water quality, leaving a critical research gap regarding the hydrochemical evolution, formation mechanisms, and drinking water safety risks of groundwater in the plain area of the Daihai Lake Basin under the dynamic conditions of ongoing water replenishment. To fill this gap, this study systematically analyzed the hydrochemical characteristics and formation mechanisms of groundwater in the study area, and conducted a comprehensive groundwater quality assessment. A suite of representative groundwater samples were collected from the study area after two years of ecological water replenishment, and analyzed using an integrated set of methods including Self-Organizing Map (SOM) clustering, hydrochemical graphical analysis, ion ratio analysis, multivariate statistical analysis, and the Entropy-weighted Water Quality Index (EWQI) method. The results show that: (1) Groundwater is divided into three clusters via SOM, with distinct ion sources from carbonate/silicate weathering and halite dissolution across clusters; some samples have excess SO₄2− and HCO₃−, requiring additional cations for charge balance. (2) Groundwater evolution is jointly controlled by water-rock interaction and evaporative concentration, with limited influence from atmospheric precipitation. (3) Three high-fluoride enrichment mechanisms are identified: mineral dissolution under weakly alkaline conditions, evaporative concentration-driven F⁻ enrichment, and accelerated dissolution of fluorine-bearing minerals induced by acidic mining wastewater. (4) 89% of Cluster-3 groundwater meets drinking standards (EWQI < 50), while 70% of groundwater samples from Cluster 1 and Cluster 2 are of poor quality, mainly distributed in the southwestern lakeshore. This study systematically elucidates the hydrochemical characteristics and formation mechanisms of groundwater in the Daihai Lake Basin under continuous ecological water replenishment, identifies key risk zones for groundwater quality, and provides a solid scientific basis for the protection and sustainable utilization of regional groundwater resources, as well as the optimization of ecological water replenishment strategies in similar arid and semi-arid inland lake basins.