DETERMINATION OF RADIOACTIVITY LEVELS IN BLACK AND WHITE SANDS USED FOR BUILDINGS AND ESTIMATION OF RADIATION HAZARDS IN THE NORTH-WEST REGION OF ETHIOPIA.

This article focuses on assessing the natural radioactivity levels and associated radiological hazards of black and white sand samples used as building materials from rivers flowing into Lake Tana in the north-west region of Ethiopia. Using gamma-ray spectrometry, the study measured activity concentrations of radionuclides radium-226 (^226Ra), thorium-232 (^232Th), and potassium-40 (^40K), finding significantly higher levels in black sands compared to white sands, with black sand values exceeding international safety limits for radium equivalent activity and hazard indices. Radiological parameters such as absorbed gamma dose rate, annual effective dose equivalent, and internal and external hazard indices were calculated, indicating potential health risks from black sand use in construction, while white sands generally remained within safe limits. The findings highlight the need for regulatory controls and continuous monitoring of sand materials to ensure safe use in building practices in the region.