Hydrochemical Characteristics and Evolution Mechanisms of Shallow Groundwater in the Alluvial–Coastal Transition Zone of the Tangshan Plain, China

作者：Shiyin Wen, Shuang Liang, Guoxing Pang, Qiang Shan, Yingying Ye, Jianan Zhang, Mingqi Dong, Linping Fu, Meng Wen · 发表于：Water · 年份：2025 · DOI：10.3390/w17192810 · 被引用次数：12 · 研究领域：Groundwater and Isotope Geochemistry、Hydrocarbon exploration and reservoir analysis、Groundwater flow and contamination studies

To elucidate the hydrochemical characteristics and evolution mechanisms of shallow groundwater in the alluvial–coastal transitional zone of the Tangshan Plain, 76 groundwater samples were collected in July 2022. An integrated approach combining Piper and Gibbs diagrams, ionic ratio analysis, multivariate statistical methods (including Pearson correlation, hierarchical cluster analysis, and principal component analysis), and PHREEQC inverse modeling was employed to identify hydrochemical facies, dominant controlling factors, and geochemical reaction pathways. Results show that groundwater in the upstream alluvial plain is predominantly of the HCO3–Ca type with low mineralization, primarily controlled by carbonate weathering, water–rock interaction, and natural recharge. In contrast, groundwater in the downstream coastal plain is characterized by high-mineralized Cl–Na type water, mainly influenced by seawater intrusion, evaporation concentration, and dissolution of evaporite minerals. The spatial distribution of groundwater follows a pattern of “freshwater in the north and inland, saline water in the south and coastal,” reflecting the transitional nature from freshwater to saline water. Ionic ratio analysis reveals a concurrent increase in Na+, Cl−, and SO42− in the coastal zone, indicating coupled processes of saline water mixing and cation exchange. Statistical analysis identifies mineralization processes, carbonate weathering, redox conditions, and anthropogenic inputs as t...