Evaluation of hydrogeochemical processes and groundwater quality for water usage in Sütçüler District, Isparta, Turkey

The present study aims to determine the hydrogeochemical properties, quality, and usage areas of groundwater used by the public, particularly for drinking and utility purposes, in Sütçüler district center of Isparta province. For this purpose, 10 samples were taken from drinking water sources in the region. The physicochemical parameters of these source waters, including major cation and anion compositions, pH, total dissolved solids (TDS), and electrical conductivity (EC) analysis results, were compared to WHO and Turkish drinking water standards (TSI266). The LAWA index was used to evaluate the suitability of groundwater quality for drinking purposes, whereas total dissolved solids (TDS), sodium adsorption rate (SAR), sodium percentage (% Na), residual sodium bicarbonate (RSC), permeability index (PI), magnesium hazard (MH), US Salinity diagram and Wilcox diagrams were used to evaluate the suitability for irrigation. In this study, it was determined that the groundwater samples are in the Ca-Mg-HCO₃ water facies. Various graphs and multivariate statistical analysis (Pearson correlation analysis and Principal Component Analysis) methods were used to determine the formation of geochemical processes constituting the hydrogeochemical facies. Given the results achieved, the dominant geochemical processes in the water were determined to be ion exchange and mineral disintegration processes originating from rock-water interaction related to limestone, dolomite, and dolomitic limestones spreading over large areas in the study area. In addition, the geochemical modeling approach was used in this study to calculate the saturation level of some selected minerals explaining the dissolution and precipitation reactions occurring in the groundwater. Accordingly, the saturation rate of all groundwater anhydrite, gypsum, and halite minerals was determined to be low. On the other hand, they were found to be oversaturated in terms of aragonite, calcite, and dolomite minerals. Considering the LAWA index, most samples are in the “Lightly polluted” class in terms of NO₃ values. Although the presence of NO₃ pollution in groundwater was reported using this method, it has not exceeded the limit values yet. According to WHO and TSI266, all the water samples are drinkable. Evaluating the usability of groundwater for irrigation purposes, it was determined that the water was suitable for irrigation. As a result, it is thought that this study will form an important basis for the sustainable quality management of groundwater resources in the study area.