Evaluation of physicochemical parameters of groundwater for drinking purposes in the Maze-Zenti catchment, Omo River Basin, Ethiopia

ABSTRACT Graphical abstract illustrating groundwater quality assessment from study-area characterization and data collection through dry- and wet-season groundwater sampling, field measurements, laboratory analysis of major ions and alkalinity, GIS-based spatial mapping, and evaluation of geogenic factors, human activities, and water quality status. Groundwater is a vital source of drinking water in the Maze-Zenti catchment, Omo River Basin, Ethiopia, yet its quality is increasingly affected by natural and anthropogenic factors. This study evaluated the physicochemical characteristics of groundwater through field measurements, laboratory analyses and spatial mapping using Geographic Information System (GIS) techniques. Samples were collected during wet and dry seasons and analyzed for pH, electrical conductivity (EC), total dissolved solids (TDS), major cations (Ca2+, Mg2+, Na+, K+), anions (HCO3−, SO42−, Cl−, NO3−, F−, CO32−), iron, and alkalinity. The results indicated that most physicochemical parameters were within the World Health Organization (WHO) and Ethiopian Standards Agency (ESA) guideline limits; however, some parameters exceeded the recommended values, indicating that the groundwater is generally suitable for drinking with localized quality concerns. Spatial distribution maps revealed seasonal and locational variations, with elevated values in densely populated and urbanized areas due to both geogenic and anthropogenic influences. Carbonate and iron contributed to water hardness and visual concerns. This study establishes a baseline for groundwater quality, highlighting the importance of ongoing monitoring to ensure safe and sustainable drinking water in the catchment.