Estimation of the Radiation Hazards Indices of Organic Fertilizers Using NaI(Tl) Gamma Spectrometer

Recently the use of organic fertilizers is increased to raise the agricultural products and reclaim land for cultivation in the world. These fertilizers contain many natural radionuclides, such as Uranium series (U-238), Thorium series (Th-232), and Potassium (K-40). Organic fertilizers can be considered as one of the natural sources of radiation in the soil. The specific activities of natural radionuclides U-238, Th-232, and K-40 in organic fertilizers were measured using a gamma-ray spectrometer NaI(Tl) detector and Rad Eye-B20 portable detector. Results of NaI(Tl) detector showed that the mean value of activity concentrations of U-238, Th-232, and K-40 was 2.101 Bq/kg, 0.329 Bq/kg, and 95.791 Bq/kg, respectively, were less than the recommended limits. The mean value of radiometric parameters Raeq, Hin, Hex, Iγ, Iɑ, DƔ, and AEDE were also calculated (9.398 Bq/kg, 0.0355, 0.0249, 0.037, 0.0123, 4.959 nGy/h, 0.0065 mSv/y). But the maximum and minimum values of activity concentration were found in sample O.2 and O.4, respectively. The results of Rad Eye-B20 portable detector showed that the maximum (0.415 Bq/cm2, 0.17 µSv/h, and 1.055 Cps) and the minimum (0.255 Bq/cm2, 0.13 µSv/h, and 0.485 Cps) values of surface contamination, Dose Rate, and General Count Rate per second were respectively found in samples O.2 and O.4; all they were slightly higher than background measurements (0.21 Bq/cm2, 0.12 µSv/h, and 0.44 Cps). Measurements of NaI(Tl) detector were matched and confirmed by Rad Eye-B20 detector. All measurements of the radiological hazard to consumers were less than the recommended limits.