Assessment of surface water quality in and around Singrauli coalfield, India and its remediation: An integrated approach of GIS, water quality index, multivariate statistics and phytoremediation

Surface water present in the form of lake, reservoir, river, etc. is regarded as one of the most significant sources of freshwater. As Singrauli district is dominated by the presence of opencast coal mines, thermal power plants, chemical industries, etc., therefore, these activities are posing adverse impact on the adjoining reservoir, thereby deteriorating its quality which is ultimately used by local population for their day to day consumption. Hence, the Singrauli district of Madhya Pradesh was chosen for the current research since both Singrauli coalfield and Govind Ballabh Pant reservoir are situated in it. In this study, the impact of mining and other industries on the water quality of the reservoir was assessed. The analytical data of 12 physico-chemical parameters for examining the water quality index (WQI) of 60 sampling sites of the area along with the statistical analysis was taken into consideration. This study utilizes the maximum number of sampling locations as compared to the previous studies conducted in the area. In addition to it, the maximum possible number of statistical analytical techniques have also been taken into consideration. The results showcased a positive correlationship between TDS with EC, TDS with Mg2+, and HCO3- with SO42-, while the analysis through the principal component has recognized two major components constituting 70.9% of the datasets. The hydro-geo-chemical facies analysis indicated Ca-Mg-Cl-SO4 as the dominant type. The succession of cations was in the order of Ca2+ > Na2+ > Mg2+ > K+ and that of the anions was HCO3- > SO42- > Cl- > NO3- > F-. Evaluation of WQI concluded that 83.33% of the samples were under good category, 8.33% under excellent, and 8.33% in the poor category as per the classification. Lastly, the three clusters illustrated an amalgamation of geogenic and anthropogenic activities. Apart from this, the adoption of phytoremediation (Eichhornia crassipes and Phragmites australis) in combination with a sandstone filtration system was also performed. The phytoremediation technique has been employed for the first time in the study area through the current research. It was observed that within 15 days of treatment, there was a considerable decrease in the amount of few of the contaminants ranging from 3 to 26%. This treated water can later be used for agricultural or industrial purposes.