Radon exhalation rate and Radionuclides in soil, phosphate, and building materials

Abstract

In the present study, The natural radioactivity in soil, phosphate, and building materials (sand, granite, marble, and limestone) were determined by using gamma ray spectrometer NaI (Tl) and MCA 1024. AlphaGUARD was used for radon exhalation rate. The data analyses were performed to determine 226 Ra, 232 Th and 40 K activity concentrations as well as 222 Rn exhalation rate. The radium equivalent activity (Raeq), external hazard index (Hex), absorbed dose rate and annual effective dose were varied from 71.66 to 9048.94 Bqkg -1 , 0.19 to 24.45, 34.48 to 4172.34 nGyh -1 and 0.04 to 5.12 mSvy -1 respectively in all samples. The mass and area exhalation rates were increased from 1.31±0.09 Bqkg -1 h -1 and 23.09±0.33 Bqm -2 h -1 , at 30 0 C, to 7.98±0.56 Bqkg - 1 h -1 and 141.11±1.52 Bqm -2 h -1 , at 60 0 C, respectively, for phosphate samples (grain size<80m). decay progeny) and the primordial radionuclide 40 K. The samples, were air dried at room temperature in open air to ensure that any residual moisture was removed from the samples. The samples were put in an oven for 48 h at 105 0 C. The soil, granite, marble and limestone samples were initially broken into coarse parts using a manual hammer. These parts were mixed using electrical sieves (FRITSCH-Germany) to obtain a homogenized material of particle size 1mm. Each samples were placed in a plastic container (250 ml), which was sealed to avoid the escape of Rn-222 and Rn-220 from the samples and left for four weeks to achieve equilibrium between 226 Ra, 232 Th and their daughter products before radiometric analysis (9).