Geological and Climatic Influences on Natural Radioactivity in Drinking Water and Their Health Impacts: A Study of Dassie and Kombolcha Towns, Ethiopia

This study investigates geological and climatic influences on natural radioactivity levels in drinking water from Dassie and Kombolcha towns in Ethiopia’s northern plateau. The basaltic and sedimentary mudrock formations of the region contain elevated natural radionuclide levels, while climatic factors such as precipitation, soil moisture, and humidity enhance their mobility and transport into water sources. Kombolcha, located at a lower altitude, shows higher radionuclide concentrations due to runoff and downward transport along the Borkena River, intensified by rainfall. Uranium’s greater solubility compared to thorium results in higher activity levels across both towns, with consistently elevated uranium and thorium values in Kombolcha. Radiation dose assessments reveal significant health risks, particularly in spring and headwater sources, where uranium concentrations exceed safe limits. These findings highlight the combined role of geology and climate in shaping natural radioactivity patterns, with important implications for long-term health risks, monitoring, and mitigation strategies.