Assessment of groundwater quality for drinking and irrigation purposes in arid areas of Rajasthan, India

The quality of groundwater is poorly understood in the arid northwest part of Rajasthan, whereas it is the only source of drinking and irrigation and the residents consume it without any prior treatment. This study illustrates the qualitative analysis of groundwater and its suitability in the bulk samples collected from three different canal catchment areas. Most of the samples were identified for higher values of EC, TDS, TH and fluoride, therefore considered posing restriction to drinking use. The abundance of major ions was found in the order of Na+ > Ca+2 > Mg+2 > K+ = Cl− > HCO3− > SO4−2 > NO3− > F−. The irrigation quality parameters such as sodium adsorption ratio, %Na, residual sodium carbonate, residual sodium bicarbonate, Kelley’s index, potential salinity, magnesium hazard, Mg/Ca ratio and permeability index were calculated and discussed thoroughly in combination with Wilcox, USSL and Doneen diagrams. Most of the samples belong to predominant Cl− and Na+ in hydrogeochemical studies. According to USSL diagram, majority of the samples fall under C4S1 class. Furthermore, groundwater chemistry was found mainly influenced by evaporation–crystallization in Gibbs variation diagram. This study suggested that groundwater is unsafe for drinking purpose without purification and quality measures should be considered while cropping in its irrigation use.