Hydrogeochemical Assessment of Groundwater for Drinking and Agricultural Use: A Case Study of Rural Areas of Alwar, Rajasthan.

Groundwater contributes substantially to the development of arid and semi-arid regions around the globe. The present study integrates groundwater quality and its suitability for drinking and irrigation around Alwar city of Rajasthan state, where agriculture is the major land use. The application for drinking was assessed by comparing the observed value with prescribed standards of WHO. Groundwater was found suitable for drinking at most of the locations. The suitability of groundwater for irrigation was determined by calculating ion-based ratios and comparing them against the suggested ratios and indices for agricultural quality. Suitability for irrigation was assessed against electrical conductivity (EC), percentage sodium (%Na), residual Na2CO3 (RSC), per cent soluble sodium (SSP), sodium adsorption ratio (SAR), Mg hazard and permeability index (PI) etc., and the quality was compromised for EC, %Na and Mg Hz. Since the soil was sandy, the groundwater was found suitable for irrigation over long-term use, with the only problem of magnesium hazard. Based on the different ratios of anions and cations, silicate weathering was observed to be regulating groundwater chemistry, and the groundwater belonged to mixed CaMgCl and CaHCO3- type based on Piper's classification and relative abundance of ions. Further, meteoric genesis classification showed that the groundwater in the study region had direct base exchange and shallow meteoric water percolation. Presence of kaolinite and quartz minerals in soil confirmed that silicate weathering is the major process controlling groundwater chemistry.