Hydrochemical processes and evolutionary mechanisms of groundwater and surface water in the Anlecun mining area: a computational study based on multivariate statistical analysis and isotope techniques

Abstract

Karst water plays a vital role in meeting daily population needs. Determining groundwater sources, understanding chemical changes, and accurately evaluating flow paths and evolution stages are essential for the protection and sustainable use of groundwater resources in mining areas.This study collected 10 sets of karst groundwater and surface water samples from the Anle Village mining area. Using multivariate statistical analysis, Piper trilinear diagrams, Gibbs diagrams, and isotopic techniques, we analyzed the hydrogeochemical characteristics of both contaminated and uncontaminated water samples.The results show that uncontaminated groundwater and surface water are slightly alkaline and dominated by Ca²⁺ and Mg²⁺ cations, along with HCO₃⁻ and SO₄²⁻ anions. Hydrochemical facies include HCO₃⁻-SO₄²⁻-Ca²⁺-Mg²⁺ and HCO₃⁻-Ca²⁺-Mg²⁺.Uncontaminated samples contain high levels of impurities, with dominance of Ca²⁺, Mg²⁺, and SO₄²⁻. These waters are mainly recharged by atmospheric precipitation and influenced by evaporation. Their chemical composition is primarily driven by the weathering and dissolution of carbonate, sulfate, and silicate rocks.Nitrate (NO₃⁻) concentrations in surface water suggest influence from agricultural fertilizers, while contaminated groundwater is closely linked to mineral resource development.These findings are significant for understanding the circulation and evolution of karst water in Anle Village and for informing the protection and utilization of local water resources.