en Radiation Biology Radiation Biology تحقيق بديع Original Research <span style="font-weight: bold"> Background:</span> Some Particular areas contain natural radionuclide at levels much higher than those usually present in earth's crust. The radiological impact of the use of zirconium ore in zirconium industry is due to internal exposure of the lung by alpha particles and external exposure of the body by the gamma rays. The result of gamma spectrometry measurement of the concentrations of the natural radionuclide in zirconium industry is described. <span style="font-weight: bold">Materials and Methods:</span> Gamma spectrometry system with a shielded high pure germanium (HPGe) detector connected to multi channel analyzer (MCA) was used to determine concentrations of natural radionuclide in about 45 samples of imported zirconium minerals, tiles, stone ware and waste sludge's of Iranian ceramic industry. <span style="font-weight: bold">Results:</span> The 238U concentration in the samples, ranging from 3000 to 10000 Bq Kg-1, is higher than the concentration of both 232Th (500-1800 Bq Kg-1), and 40K (50-800 Bq Kg-1). The measured specific activities in the mineral showed that specific activity of baddeleyite is higher than that of zircon. The results of ceramic tiles show that the tiles usually contain small amount of zirconium compound. <span style="font-weight: bold">Conclusion:</span> Due to relatively high concentration level of uranium in imported zirconium samples, specific regulations is necessary for zirconium compound used in ceramic industry. Iran. J. Radiat. Res., 2007 4 (4): 201-204 Natural radioactivity, ceramic industry, gamma spectrometry, zirconium mineral. 201 294 http://ijrr.com/browse.php?a_code=A-10-1-224&slc_lang=en&sid=1 A.A. Fathivand afathivand@yahoo.com 79003194753284600684 79003194753284600684 Yes J. Amidi 79003194753284600685 79003194753284600685 No S. Hafezi 79003194753284600686 79003194753284600686 No