Hydrochemical Characteristics and Quality Assessment of Stream Water in Parts of Gadag, Koppal and Ballery Districts of Karnataka, India

Abstract

Seventeen water samples were collected from various streams in parts of Gadag, Koppal and Ballery districts of Karnataka and analyzed for major ions and heavy metals to determine the processes controlling surface water chemistry and suitability of water for drinking, livestock uses and irrigation purposes. The water samples are moderately alkaline to alkaline in nature and soft to moderately hard. The order of cations is Na>Ca>Mg>K, of anions is HCO3>Cl>SO4>CO3>NO3 and heavy metals Sr>Fe>V>Ba>Zn>Ni>Mn>As>Cu>Cr>Pb>Co. According to Gibbs diagram, the water samples fall in the dominant rock-water interaction area, suggesting chemical weathering of the rock forming minerals as the main process contributing ions to the surface water. Scatter plots of Ca + Mg vs HCO3 + SO4 and Ca/Na vs HCO3/Na clearly indicate the silicate weathering playing a dominant role on water chemistry. The evolution of surface water into Ca-Na-HCO3 and Ca-HCO3 water types is due to easy dissolution of silicate minerals and less time for water-rock interaction. Surface water samples are characterized by Na-Ca-HCO3-Cl the principal water type of schoeller’s plot, which can be related to the weathering of the silicate rocks along with some anthropogenic input. The physical parameters, major ions and heavy metals are within the permissible limits of WHO and BIS standards except for two samples, suggesting the water as suitable for domestic and livestock uses. The stream water is suitable for irrigation as per the quality parameters and plots including EC, sodium percent, sodium adsorption ratio, Wilcox and USDA classification diagrams.