Hydrogeochemical evolution and quality assessment of groundwater in the Voltaian aquifer, Krachi East Municipality, Ghana using chemometric and geochemical modeling approaches

Groundwater quality in the Voltaian aquifer of Krachi East Municipality, Oti Region, remains poorly understood, creating a gap in sustainable water resource management. Therefore, this study aimed to characterize groundwater chemistry, identify controlling processes, and assess its suitability for domestic and agricultural use. Sixteen groundwater samples were analyzed using hydrochemical parameters, spatial mapping, Gibbs diagrams, bivariate plots, and multivariate statistical techniques (factor analysis, correlation matrix, and cluster analysis). Results show slightly alkaline pH (6.85–7.87; mean = 7.32), low electrical conductivity (403–708 μS/cm, mean = 489 μS/cm), and low total dissolved solids (276–388 mg/L, mean = 363 mg/L). The dominant hydrochemical facies (81.25% of samples) was Na–HCO3 type. The WQI values ranged from 22.4 to 57.1, with an average of 33.4, confirming excellent quality for drinking. However, Na% ranged from 49.9 to 98.4% (average 81.6%), signalling high sodicity risk for irrigation. Spatial maps revealed heterogeneity in major ions, while Gibbs plots and saturation indices indicated that rock weathering, carbonate and silicate dissolution, and ion exchange are the primary geogenic processes. Anthropogenic influences, notably agriculture, also contribute to groundwater chemistry. These findings highlight that while the Voltaian aquifer provides safe drinking water, elevated sodium and magnesium levels pose challenges for long-term agricultural sustainability. The findings constitute the first integrated chemometric and geochemical modeling assessment in the Krachi East segment of the Voltaian Basin, clarifying dominant processes and revealing irrigation sodicity risks that are critical for sustainable groundwater management. The study offers critical insights into hydrogeochemical evolution and informs strategies for sustainable groundwater management in Krachi East Municipality.