Hydrogeochemical characterization and integrated groundwater quality assessment using CCME-WQI, multivariate...

The current study examines hydrogeochemical characteristics along with suitability of groundwater quality using Canadian Council of Ministers of the Environment Water Quality Index (CCME WQI) and multiple irrigation indices in Ambedkar Nagar region, India. A total of 36 groundwater samples and 16 physicochemical parameters were analysed. The concentrations of some variables such as turbidity, TDS, Ca²⁺, Mg²⁺, Hardness, SO₄²⁻ Alkalinity and Iron were exceeded WHO recommendations at a few sites, signifying severe water quality concerns and remaining were within the acceptable limit. The CCME WQI findings quantify that the majority of groundwater samples, 97.2% assessed as excellent to fair, poses no threat to human health and found appropriate for drinking uses meanwhile, remaining 2.8% of samples required minor treatment before use. Based on correlation analysis, significant strong positive correlations including TDS-EC (r = 1.0), TDS-Cl (r = 0.72), TDS-TH (r = 0.83), EC-Cl (r = 0.72), and EC-TH (r = 0.83), emphasizing a common source while, Turbidity, TDS, EC, Alkalinity, TH, and Fe possessed negative correlations with CCME WQI, signifying that higher concentration of these variables correspond to lower groundwater quality. HCA classified based on CCME WQI scores: Cluster-I categorized 06 (16.7%) site, as excellent, Cluster-II 21 (58.3%) sites, as good, Cluster-III 08 (22.2%) sites, as fair, and Cluster-IV 01 (2.8%) site, as marginal class. Based on Piper plot, 94.5% of samples were classified as Ca-Mg-Cl-SO₄^- facies, while 5.5% samples denote Ca-Mg-HCO₃^- facies, majorly signifying rock-water interactions and anthropogenic influence. Furthermore, Gibbs plot showed a most of the samples belong to the rock dominance types, are only the governing factor of groundwater chemistry. Principal component analysis, with sufficient KMO (0.645) with important Bartlett's test data (p < 0.001), revealed the essential factors impacting groundwater chemistry. Based on irrigational indices (EC, SAR, RSC, SSP, MH, PS, KR, and Wilcox and USSL diagrams), it has been confirmed that the majority of the samples are suitable for irrigation uses.