A Comparative Analysis of Fluoride Contamination in a Part of Western India and Indus River Basin

Abstract

Fast-growing population, water demand, and the presence of inorganic contaminants in groundwater of arid and semiarid region have created a need for quality assurance before the domestic water supply. Altogether, 30 water samples were collected from Jaisalmer (10 samples each from Jaisalmer and Pokhran blocks) and Bhatinda (10 samples) districts of Rajasthan and Punjab, respectively, and analyzed for major ions and water quality parameters. Results suggest that most of the groundwater samples are alkaline in nature with high electrical conductivity. Based on the mean value, most of the ions such as Na⁺, ${{\text{SO}}_{4}}^{2 - }$, Cl⁻, ${{\text{NO}}_{3}}^{ - }$, and F⁻ are found to be above the WHO guideline for drinking water. Geochemical modeling and conventional graphical plots are used to decipher the groundwater chemistry. Mg–HCO₃ is found as the most dominant water type followed by Na–HCO₃ and Na–Cl in Bhatinda, while in Jaisalmer and Pokhran Na–Cl is found as the most dominant water type except one sample which shows water facies of Na–HCO₃ type. Fluoride is found as the major contaminant in all the three regions as F varied from 1.9 to 4.5 mg/L in Jaisalmer, while in Pokhran and Bhatinda it has varied between 1.1 and 6.1 mg/L and 0.8 and 4.0 mg/L, respectively. About 60% of the samples from Bhatinda, 100% samples in Jaisalmer, and 90% of the samples from Pokhran contain F > 1.5 mg/L. Most of the samples are undersaturated with fluorite and gypsum while oversaturated with calcite and dolomite suggesting dissolution of fluorite as a major contributor for high F⁻ in groundwater of the study areas.