Hydro-chemical Survey and Quantifying Spatial Variations of Groundwater Quality in Dwarka, Sub-city of Delhi, India

Abstract

Hydrological and geological aspect of the region play vital role for water resources utilization and development. Protection and management of groundwater resources are possible with the study of spatio-temporal water quality parameters. The study was undertaken to assess the deterioration in groundwater quality, through systematic sampling during post monsoon seasons of the year 2008 by collecting water samples from thirty bore wells located in Dwarka, sub-city of Delhi, India. The average concentrations of groundwater quality parameters namely Calcium (Ca2+), Magnesium (Mg2+), Nitrate (NO3−), Chloride (Cl−), sulphate (SO42−), total hardness (TH), total dissolved solids (TDS), and electrical conductivity were 300, 178, 26.5, 301, 103, 483, 1042 mg/l and 1909 μS/cm respectively. Estimated physico-chemical parameters revealed that 7 % of the groundwater samples shown nitrate concentrations higher than safe limit prescribed by World Health Organization (WHO). Groundwater quality the in study region was poor due to come out result that NO3− concentration exceeding the threshold value of 50 mg/l, and main cause is disposal of sewage and animal wastes to Najafgarh drain. Dominant cations are Mg2+, Ca2+ and anions are SO42− and Cl−. The abundance of the major ions in groundwater is in the order: Ca2+ > Mg2+ and Cl− > SO42− > NO3. TH have strong correlation with Ca2+ (r = 0.81), Mg2+ (r = 0.82), Cl− (r = 0.86) but poor correlation with TDS (r = 0.52). Knowledge of correlation values between water quality parameters is helpful to take decision of appropriate management strategy for controlling groundwater pollution.