[Hydrochemical Characteristics and Controlling Factors of Groundwater in the Leizhou Peninsula]

Groundwater resources in the Leizhou Peninsula provide a strong support for the economic and social development. Therefore, understanding the chemical characteristics and formation mechanism of groundwater in this area is necessary for the rational exploitation and sustainable utilization of water resources. In this study, 43 groundwater samples were collected, and the hydrochemical characteristics and controlling factors were analyzed by descriptive statistical analysis, Piper triangular diagrams, ArcGIS spatial interpolation, Gibbs diagram, and ion ratios. The results showed that:① The anions and cations of the groundwater in the study area were mainly HCO₃^-, Ca²⁺, and Na⁺, and the hydrochemical types were mainly HCO₃-Cl-Na-Ca, HCO₃-Cl-Na-Ca-Mg, HCO₃-Cl-Na-Mg, and HCO₃-Na. The contents of Cl^-, SO₄^2-, and Na⁺were higher in the west of Leizhou City compared to other areas. The sites with higher contents of HCO₃^-, NO₃^-, Ca²⁺, Mg²⁺, and K⁺ were mainly concentrated in the southwest and eastern coastal areas. ② The chemical evolution of groundwater was mainly affected by water-rock interaction, cation alternating adsorption, and anthropogenic activities. The sources of Na⁺ and K⁺ were mainly from evaporative and silicate rocks, Ca²⁺ and Mg²⁺ were mainly from carbonate karstification, while NO₃^- originated from anthropogenic activities.