Hydrogeochemical and Geostatistical Evaluation of Groundwater Quality In Semi-Arid Region of Eastern Rajasthan: A PCA and Geospatial-Based Approach

The increasing demand for freshwater resources due to population growth and associated activities has exacerbated groundwater quality challenges, especially in semi-arid regions. This study evaluates the hydro-geochemical properties of groundwater in eastern Rajasthan, using geostatistical methods integrated with Principal Component Analysis (PCA) and geospatial techniques. A comprehensive field examination collected groundwater samples from 36 sites and assessed 14 hydrogeochemical parameters, including Sodium, Potassium, Calcium, Magnesium, pH, Total Hardness, TDS, Conductivity, Alkalinity, Nitrite, Bicarbonate, Fluoride, Chloride, Iron (Fe), and Depth. The majority of samples revealed Na-Cl-type characteristics with evaporation dominance. A strong positive association was observed between Na⁺ and EC (r = +0.95) and between Alkalinity and HCO3- (r = + 0.94), while a negative association was identified between HCO3- and depth (r = - 0.45) and between Ca++-Mg++ and pH (-0.43). In addition, Wilcox diagrams classified most groundwater sources as permitted to dubious. The PCA analysis identified four main components, accounting for 85.86% of the variance. Component 1 (40.41%) comprised Na⁺, EC, TDS, HCO₃⁻, and Alkalinity, whereas Component 2 (20.66%) contained TH, F⁻, Ca⁺-Mg⁺⁺, and K⁺. These findings suggest that geochemical processes affect groundwater quality and that semi-arid regions require sustainable groundwater management.