Hydrogeochemical investigation of groundwater quality in west Delhi, India

Abstract

The hydrogeochemical parameters for groundwater of west Delhi were studied to evaluate the major ion chemistry and solute acquisition processes controlling water composition, scaling potential and permeability of groundwater. Ninety three groundwater samples were collected randomly from dug wells and hand pumps in west Delhi and analyzed for various chemical parameters. The concentrations of major cations and anions were in the order of Na > Mg > Ca > K and Cl > SO > HCO > NO , respectively. The main hydrochemical facets of +--- -- 433 water were Na-K-Cl-SO and Ca-Mg-SO -Cl types. The electrical conductivity (EC) represents a clear sign of groundwater contamination from drain water and 44 salts of unused agrochemicals. The Gibbs diagram indicates that evaporation is the dominant mechanism that control groundwater ion chemistry. Chloride distribution in the study area showed that, groundwater with chloride -1 concentration of < 30 meq L is originated naturally, but the origin of higher concentration is anthropogenic in nature. 86% of the samples have scale forming ability and only 14% are showing corrosive tendency. The encrustation tendency is due to CaCO precipitation and hence need for treatment of water to prevent 3

scaling. In general, the permeability index indicate good to permissible use of water for irrigation, and only a few locations demand remedial measures for better crop yields. USSL and Wilcox diagram showed that nearly 60% of the groundwater samples are not suitable for irrigation. Thus, this kind of investigation can create suitable management plans to protect aquifer as well as remedial measures for contaminated groundwater by natural and manmade activities.