Integration of multivariate statistics and water quality indices to evaluate groundwater quality and its suitability in middle Gangetic floodplain, Bihar

摘要

This study is conducted along the middle Gangetic floodplain, to investigate the hydrogeochemical characteristics andsuitability of groundwater for irrigation and human consumptions. Altogether 65 groundwater samples were collectedand analyzed for major ions and water quality parameters. pH of all the samples except 1 is found > 7, which suggestsalkaline aquifer condition. Groundwater samples predominately belong to Ca-Mg-HCO_3 water type followed by Na-HCO_3, Mg-HCO_3 and Mg-SO_4 water types. Hierarchical cluster analysis (HCA) combines groundwater into two distinctgroups, Group 1 is found as less mineralized as the average EC value is found 625.3 μS/cm, while it is found 1375 μS/cm for Group 2. The results of correlation analysis and PCA suggest influence of natural and anthropogenic activitieson groundwater. PCA extracts four major PCs which describes 71.7% of total variance. PC1 indicates influence of bothlithogenic and anthropogenic activities on groundwater quality. PC2 and PC3 infer natural factors, and PC4 suggestsinfluence of anthropogenic activities on groundwater. Exceeding concentration of F−,Fe and Mn above WHO guidelinesare found as major public health concern. WQI of all except 4 groundwater samples suggests excellent to good waterquality; however, 23% of the samples are not suitable based on WPI values. Irrigation indices suggest that groundwateris mostly suitable for irrigation; however, 10.7%, 12.3% and 3% samples for RSBC, MAR and KR, respectively, exceed therecommended limits and are unsuitable for irrigation. A proper management strategy and quality assurance is recommendedbefore groundwater consumption and use in the study area.