Hydrochemical Characterization and Groundwater Quality Assessment under Natural and Anthropogenically Influenced Areas of Lower Gangetic Plains, West Bengal

A study was conducted in the Murshidabad district of West Bengal to examine the water quality and mechanism responsible for hydro-geochemistry of the groundwater falling under the natural and anthropogenically intervened areas. For this purpose, twenty-five groundwater samples were collected from the tube wells in April 2022. Samples are analyzed for various hydrochemical parameters such as pH, EC, Total hardness, TDS, major cations and anions NO3, F, and Fe. The hydrochemical parameters were tested for drinking purposes and based on these hydrochemical parameters, the water quality index (WQI) was calculated. The analytical results revealed that groundwater is alkaline in nature and hard. TDS, EC, Mg, K, HCO3, NO3, and Fe of the groundwater exceeded the desirable drinking limits. All groundwater samples show iron contamination. Ca+ Mg-HCO3 is the pre-dominant hydro chemical facies. The WQI showed that 8, 28, 36, 20, and 8% of the samples of the research region lie in the “Excellent,” “Good,” “Poor,” “Very poor,” and “Unfit for drinking” categories. The Gibbs, other bivariate plots and Durov diagram indicated that the silicate weathering processes with reverse ion exchange governing the water chemistry. Correlation and land use/land cover analysis indicate the significant contribution of anthropogenic influence. These contaminants are mainly due to the contamination from a landfill site, drains and nalas carrying domestic sewage, and the excessive application of synthetic/organic fertilizers. The results of this study not only reflect the geogenic and anthropogenic influences on groundwater quality; they are also helpful in identifying the potential sources of contaminants.