Implementation Of Water Quality Index For Measuring Groundwater Quality

Abstract

Groundwater is one of the major sources of water consumption in developing countries. The aim of the study was to investigate the variations in physicochemical characteristics and metal content and to calculate the Water Quality Index (WQI) to assess the groundwater quality of seven districts (Central, East, West, South, Malir, Korangi, and Kemari) of Karachi City, Pakistan. A stratified sampling approach was used to collect groundwater samples and turbidity, pH, Electrical Conductivity (EC), Total Dissolved Solids (TDS), Total Suspended Solids (TSS), Nitrate-N, and arsenic concentrations were investigated to profile WQI. The physicochemical parameters from districts South, West, Korangi, and Kemari were as per APHA standards and found suitable for drinking purposes. EC and TDS were in ranges of (2660-3870μS/cm) and (1596-2322mg/L) exceeding the standard limits resulting in poor drinking water quality respectively in districts Central, Malir, and East. These districts fail to meet the APHA standards and become unfit for human consumption on the WQI scale. However, TSS and arsenic was not detected in any of the collected samples. The correlation matrix for the[1] correlation coefficient (R-value) of tested parameters with WQI indicated significant linear and high R-value among tested parameters. The statistical analysis showed that turbidity, pH, EC, TDS, and Nitrate-N have significant effects on WQI. EC and TDS showed a direct correlation with WQI (R=1.0) whereas turbidity significantly correlates with the presence of nitrate in drinking water (R=0.64). These findings help the decision makers to plan mitigation strategies for comprehensive water quality monitoring of the respective areas and ensure the availability of clean and safe drinking water to the public.