浅层地下水水化学演化特征及其形成机制研究——以蒙城县周边为例

Study on the Hydrochemical Evolution Characteristics and Formation Mechanism of Shallow Groundwater—Taking the Surrounding Area of Mengcheng County as an Example

摘要: 为揭示蒙城县周边的浅层地下水水化学演化特征及其形成机制，在研究区采集了40组浅层地下水样品，并综合运用了描述性统计分析、离子比值分析、相关性分析、主成分分析、Gibbs图以及Piper三线图等多种方法。本文探讨了研究区地下水的常规离子组成特征，明确了地下水化学类型及其形成原因，并分析了不同来源地下水水化学特征。研究结果可知，研究区域pH在6.60~7.40之间，均值为7.08，为弱碱性水；TDS介于250~1056 mg·L⁻¹，均值为426.34 mg·L⁻¹，属于淡水型。EC在249~1873 uS/cm,平均值为782.69 us/cm。阴阳离子主要以${\text{HCO}}_3^{-}$ 和Ca²⁺为主，水化学类型以HCO₃-Ca型为主导。

Abstract: In order to reveal the hydrochemical evolution of shallow groundwater around Mengcheng County, forty shallow groundwater samples were collected in the study area. The analysis methods contain descriptive statistical analysis, ion ratio analysis, correlation analysis, principal component analysis, Gibbs diagram and Piper three-line diagram. The conventional ionic composition characteristic is discussed, the chemical types of groundwater and their formation is clarified, the sources contribution of the hydrochemical properties is also explained. The results showed that the pH of the study area was between 6.60~7.40, the average value is 7.08, which is weakly alkaline water, the TDS is between 250~1056 mg·L⁻¹, and the mean value is 426.34 mg·L⁻¹, which belongs to the freshwater type. The EC is 249~1873 uS/cm, and the average value is 782.69 us/cm. The anions and cations were mainly ${\text{HCO}}_3^{-}$ and Ca²⁺, and the hydrochemical types were dominated by HCO₃-Ca.