Assessment of groundwater quality status by using water quality index (WQI) and geographic information system (GIS) approaches: a case study of the Bokaro district, India

One hundred two groundwater samples were collected from the Bokaro district of Jharkhand state, India, during the pre-and post-monsoon seasons of the year 2014-2015. In the present study, groundwater samples were analysed for pH, TDS, TH, Ca2+, Mg2+, Na+, K+, Cl-, SO42-, HCO3-, F- and NO3- to evaluate the suitability of the groundwater for drinking purposes through geographic information system (GIS)-based water quality index (WQI) model. For quality assessment, values of analysed parameters of the groundwater samples were compared with the Bureau of Indian standards (BIS) and World Health Organization (WHO) water quality standards. The analytical results indicate slightly acidic to slightly alkaline nature of the groundwater in the study area. Concentrations of Ca2+, Mg2+, HCO3-, F-, NO3-, TDS and TH exceeded the desirable as well as permissible limits of drinking water quality standards recommended by the BIS (Indian Standard Drinking Water Specification, 2012) and WHO (Guidelines for drinking water quality: training pack, WHO, Geneva, 2004) in the study area during the pre- and post-monsoon seasons, respectively. However, Na+, K+, Cl- and SO42- concentrations were within the permissible limits during both seasons. The hydrochemical analysis of the studied groundwater samples documented with ternary and Durov diagram revealed that most of the groundwater samples belong to HCO3- type of anions facies and no dominant type of cation facies. The GIS-based WQI maps for the study area indicate that the poor quality of water was found the maximum in the pre-monsoon season as compared to the post-monsoon season in the study area, respectively. The high values of WQI in the several groundwater samples of the Bokaro district indicate that water is not suitable for direct consumptions and it required sustainable treatment before its utilization for drinking uses.