Evaluation of groundwater quality in West Tripura, Northeast India, through combined application of water quality index and multivariate statistical techniques

Groundwater is one of the major resources of civilization which cannot be visualized directly in day to day life. Scarcity of groundwater is an alarming threat to the ecosystem. The present study was conducted to evaluate water quality and interrelated environmental impact of 38 groundwater samples applying the water quality index (WQI) method and multivariate statistical tools. This investigation includes some techniques like weighted arithmetic and entropy weight WQI, principal component analysis (PCA), correlation analysis (r), cluster analysis (CA), and spatial mapping. The data required for these tools were used after the estimation of physicochemical parameters of each sample. Calculated WQI values identified iron (Fe) followed by turbidity and dissolved oxygen (DO) as the most influencing parameters for non-potability of groundwater samples. Fe contamination in 34 samples exceeded WHO standard limit (0.3–1 mg/L) and the maximum value was recorded as 15.23 mg/L. Findings of correlation matrix (r) suggest all ions have a common source and geochemical processes. Outcomes of PCA followed by a scree plot diagram extracted three major factors with a total variance of 84.5% clarifying the explanations behind water quality deterioration. Based on data ranges of all parameters, the spatial distribution map has been procured following the methods for identification and management. CA investigated three major groups using Ward’s method of either sampling locations or analyzed parameters and showing through dendrogram plots. Considering all the above, it is suggested that physicochemical parameters should be monitored periodically to preserve water resources and provide emphasis on management practices to maintain water quality.