Hydrogeochemical characteristics and groundwater quality assessment in the Asutifi North District, Ahafo Region, Ghana

This study examined twenty-three (23) groundwater samples to determine the hydrogeochemistry of water in Ghana’s Asutifi North District. The primary objective was to characterize and assess the groundwater quality in the district, which is underlain by Paleoproterozoic supracrustal and intrusive rocks of the Birimian Supergroup. This was accomplished by employing a multi-method approach that included geochemical analysis, multivariate statistical analysis, water quality assessment, and geochemical modeling. Unlike previous studies in the district that examined geochemical mechanisms without assessing water potability, this study integrates hydrogeochemical analysis with water quality assessment for both drinking and agricultural use of groundwater in the district. The pH (6.2–7.6) of groundwater is moderately alkaline owing to aquifer chemistry. The major ion concentrations fall within the World Health Organization guidelines for potable water. The cationic composition followed the order Na+ >Mg2+ >K+ >Ca2+, while the anionic composition was HCO3− >NO3− >Cl− >F−. The NO₃⁻ concentrations ranged from 0.20 to 95.6 mg/L with ~ 9% of the samples exceeding the guideline value of 50 mg/L. Piper diagram identifies Na-HCO3 as the dominant water type, with other mixed water types also present. Factor Analysis (FA) identified five factors with eigenvalues greater than 1, explaining 85.56% of the total variance in the hydrochemical parameters. The FA results highlight natural processes, such as the dissolution of silicate and carbonate minerals, and anthropogenic activities, including the use of phosphate and nitrate fertilizers, as key contributors to the aquifer’s chemical composition. The computed water quality index ranged from 11.8 to 47.5 for the sampled groundwater, indicating that the groundwater is of excellent quality and fit for human consumption. However, the high magnesium ratio (> 50) and sodium percent values (> 60%) show that the water is not suitable for irrigation usage.