Groundwater Quality Assessment through Water Quality Index (WQI) in New Karachi Town,Karachi,Pakistan

The aim of present study is to evaluate the groundwater quality of New Karachi Town using water quality index (WQI) measured through physico-chemical parameters. For this purpose, a total of 25 groundwater samples were randomly collected through boring wells at a depth range of 9-61 metres from the study area. Data revealed that TDS content of groundwater is very high (mean: 4781.6 mg/L) which far exceeded the WHO limit for drinking purpose. Highly elevated concentrations of Na (mean: 1397 mg/L), K (mean: 39.72 mg/L), Ca (mean: 308.7 mg/L), Mg (mean: 1408.65 mg/L), Cl (mean: 2502.345 mg/L), HCO₃ (mean: 441 mg/L) and SO₄ (mean: 332.4376 mg/L) are reported in more than 85% wells which also exceed the WHO guideline for drinking water. Very high concentration of these major ions (Mg, K, Ca, Na, Cl, SO₄ and HCO₃) indicates the sewage mixing with groundwater in the study area. The calculated value of water quality index (WQI = 189) indicated that groundwater in New Karachi Town is not suitable for drinking and for irrigation or industrial purpose. Thus, proper treatment of the available groundwater is required before its any public use in the area.