Hydrogeochemical Evaluation of Groundwater Quality for Drinking and Irrigation Purposes and Integrated Interpretation with Water Quality Index Studies

Groundwater is the major source for drinking and irrigation purposes in the Central parts of Telangana. The demand for groundwater has recently increased due to intensive irrigation practices and population growth which in turn caused depletion of resource and deterioration of quality. In view of this, quality studies have been undertaken on 105 groundwater samples collected from the rock dominant semi-arid region of central Telangana and analysed for pH, electrical conductivity (EC), total dissolved solids (TDS), total hardness (TH), calcium (Ca2+), magnesium (Mg2+), sodium (Na+), potassium (K+), chloride (Cl-), sulphate (SO42-), nitrate (NO3-), and fluoride (F-). Results revealed that 51% and 71% of groundwater has more than the maximum acceptable limits of fluoride (1.5 mg/L) and nitrate concentrations (45 mg/L), respectively, thus making the groundwater unsuitable for drinking purpose. Data plotted in Gibbs diagram reveal that the groundwater chemistry is primarily controlled by rock-water interaction. According to water quality index (WQI), 60% and 36% of groundwater samples fall in excellent and good categories for drinking purpose. A majority of groundwater samples fall in deep meteoric percolation and Na+-SO42- types, but most belong to Ca2+-Mg2+-HCO3-, Na+-HCO3- facies, and few are of Ca2+-Mg2+-Cl- and Na+-Cl- facies. 90% of groundwater in the study region is well suitable for irrigation. It is advised that groundwater with high fluoride and nitrate concentration should be avoided for drinking purposes.