Estimation of Environmental Impacts of NORM from Some Raw Materials Used in Ceramic Industry

摘要

Common raw materials used in ceramic industry in Egypt have been collected from different ceramic factories. The samples were tested for their natural radioactivity contents by using HPGe high-resolution y-ray spectrometer. Various radionuclides of the samples have been identified quantitatively based on their characteristic spectral peaks. The natural radioactivity due to the presence of ~(238)U, ~(226)Ra, ~(232)Th, and ~(40)K and the radiological parameters for 15 raw materials were measured. The three raw materials with the highest radioactivity were quantitatively analyzed using X-ray fluorescence (XRF). The most abundant oxides measured were generally SiO_2, ZrO_2, ZnO, Fe_2O_3, and CaO. The highest mean values of ~(238)U, ~(226)Ra, and ~(232)Th activities were 394 ± 6, 428 ± 8, and 61.1 ± 1.5 Bq kg~(-1) (in zircon), and the highest ~(40)K activity was 283 ± 4 Bq kg~(-1) (Aswan clay). The radium equivalent activities and some hazard indices were also calculated to assess the radiation hazards. The maximum mean value of the radium equivalent activity Ra_(eq) is 516 ± 10 Bq kg~(-1) (in zircon). The highest radioactivity level and dose rate in air were also obtained for zircon. The total absorbed dose rates in air, calculated from the concentrations of the three radionuclides, range from 4.29 ± 0.18 to 461 ± 9 nGy h~(-1); the external annual effective dose rates were determined to be between 0.03 ± 0.003 and 4.35 ± 0.23 mSv.