Appraisal of groundwater quality for drinking and irrigation purposes in Central Telangana, India

Abstract

Groundwater is only an important water resources for drinking and irrigation in the central Telangana, India. Rapid growth in the population and intensive irrigation practises has become stress on groundwater, the available groundwater are being depleted and its quality has also deteriorated. For this reason, a total of 105 groundwater samples collected from semi-arid region of central Telangana, were executed in order to evaluate its suitability for drinking and irrigation purposes. Results highlighted that most of the groundwater is suitable for drinking purposes based on pH, electrical conductivity (EC), total dissolved solids (TDS), total hardness (TH) as CaCO3, calcium (Ca2+), magnesium (Mg2+), sodium (Na+), potassium (K+), chloride (Cl−), and sulphate (SO42−). About, 51% and 71% of groundwater samples were exceeded the maximum permissible limits of fluoride and nitrate, respectively. Therefore, it is suggested that groundwater with high fluoride and nitrate concentration water should be avoided for drinking purposes. Spatial distribution maps are generated using GIS platform and the dissimilar distribution pattern was noticed for nitrate and fluoride in the study region. Gibbs plots authenticate that the groundwater chemistry is controlled by rock-water interaction and geochemical scatter plots suggested that the silicate mineral dissolution play dominant role in the chemistry of groundwater. According to the water quality index (WQI) values, 60% and 36% of groundwater samples fall under excellent and good category for drinking purposes. The groundwater is Na+ - SO42−, deep meteoric percolation type, but most of it belong to Ca2+–Mg2+–HCO3−, Na+–HCO3− facies and few are Ca2+–Mg2+–Cl− and Na+-Cl- facies. Majority of groundwater samples exhibit that the alkaline earths (Ca2+ + Mg2+) exceed alkali cation (Na+ + K+) and strong acids (SO42− + Cl−) dominate over weak acid (HCO3−). Irrigational suitability of groundwater in the study area was also estimated through sodium adsorption ratio (SAR), sodium percentage (%Na), and residual sodium carbonate (RSC), magnesium hazard ratio (MHR), and Kelly ratio (KR) results shown that the majority of the groundwater samples were suitable for irrigation uses.