Multivariate Statistical Approach to Deduce Hydrogeochemical Processes in the Groundwater Environment of Begusarai District, Bihar

摘要

This work gives us an overview of the groundwater quality and problems pertaining to the occurrence of arsenic (As) and other chemical contaminants in the groundwater of Begusarai district of Bihar, India. The total As concentration in the analyzed water samples varies between 21.5–94.3 μg/L. Through the saturation index using PhreeqC, it was found that most of the samples are saturated for mineral goethite, calcite and dolomite. It was observed that mobilization of arsenic from the alluvial aquifers is mainly affected through the means of reductive dissolution of the iron oxyhydroxides within the sediments. Reductive dissolution of iron oxyhydroxide present as coatings on and around clay layer seems to be the main process responsible for the release of As into groundwater. Close to the Gangetic flood plain most of the tube wells (shallow aquifers) are affected. Groundwater is characterized by slightly alkaline pH with a moderate to strong reducing nature. The water type mainly falls in two categories i.e. Ca–HCO₃ and Ca–Cl (with contribution of 75 and 25% of total water type, respectively). Enrichment of NO₃-mathrm{NO}_{3}^{-} at few locations is an indicator of agriculture practice well supported by effluent leaching.