2.2.2. Methods

In this study, the hydrochemical characteristics of groundwater were analyzed from four aspects: the concentration characteristics of hydrochemical indices, spatial distribution, hydrochemical facies and correlation analysis among hydrochemical indices. Second, the hydrochemical evolution mechanisms were further studied by applying hydrochemical methods. Then, the main source of groundwater was recognized by using the D–18O isotope technique. Based on the evaluation of groundwater quality, the main sources of nitrate in groundwater were identified by integrating the hydrochemical and isotopic data. The methodology flowchart (Figure 2) is shown below.
