Hydrogeochemical characterization of groundwater in Aksum district, northern Ethiopia: Implications for drinking and irrigation uses

The Aksum district in northern Ethiopia is well-known for its water scarcity, where the water demand exceeds the available supply due to rapid urbanization, population, and economic growth. Groundwater serves as a vital freshwater source in this semi-arid region. However, its quality for drinking and irrigation consumption remains underexplored. This study examines the hydrogeochemical properties of the groundwater of the area, characterized by diverse geological formations. Eighteen groundwater samples were collected and analyzed for physicochemical properties in accordance with American Public Health Association (APHA) standards, using Atomic Absorption Spectrometry and Ultraviolet Spectrometry. The hydrogeochemical parameters were compared with the Ethiopian and World Health Organization (WHO) standards established for drinking and agricultural water. The results revealed that of the groundwater samples were unsuitable for drinking water purposes, largely due to high levels of calcium, potassium, total dissolved solids, electrical conductivity, bicarbonates, and total hardness, particularly in areas underlain by the mudstone units. These physicochemical parameters of some groundwater samples exceeded acceptable limits for drinking water, calling for physicochemical treatment before consumption. Groundwater quality indices such as sodium percentage (%Na), sodium absorption ratio (SAR), Kelly’s Ratio (KR), permeability index (PI), Potential salinity (PS), and residual sodium bicarbonate (RSBC) were evaluated to assess their suitability for irrigation uses. Findings of these indices indicate that the groundwater in the area is generally suitable for irrigation purposes and poses minimal risk. However, few samples surpassed the standards for use, suggesting that proper management of it is still essential to avoid potential problems associated with salinity. The predominant groundwater type identified was Ca-Mg-Na-HCO3, influenced by weathering processes and water-rock interactions. Therefore, this investigation underscores the urgent need for effective groundwater management strategies to address quality issues and promote sustainable use for drinking purposes, especially.