Radiological characteristics of NORMs and transfer factor in an agricultural farm in Ondo Nigeria

Naturally occurring radionuclides in agricultural soils presents considerable public health concerns due to the capability of the radionuclides transfer from soil to plants. The study determined the radionuclide activity in the soil and food crop samples collected in the extensively cultivated Teaching and Research Farm, Adeyemi Federal University of Education, Ondo, Nigeria. A total of forty-five samples (30 soil samples and 15 food crops samples) were collected and the activity concentrations were measured by employing gamma ray spectrometry. The measured activity concentrations were subjected to radiological indices: Radium Equivalent (Ra eq ), Internal hazard index (H in ), External hazard index (H ex ), Gamma index (I γ ), Absorbed Dose (D), Annual Effective Dose Equivalent (AEDE) and Excess Life Cancer Risk (ELCR) to estimate the radiological risks and the soil-to-plant transfer factor were also estimated. The average activity concentrations of 238 U, 232 Th and 40 K for soil samples were 3.74, 10.03 and 1021.59 BqKg −1 , respectively. The average values of Ra eq , H in , H ex , I γ , D, AEDE and ELCR were 96.74 BqKg −1 , 0.27, 0.26, 0.81, 6.93, 69.08 nGyh −1 , 53.10 µSvy −1 and 1.86 × 10 –4 . The values of radiological indices were lower than the recommended safety limit for public protection from adverse radiation implications. The results of the transfer factor were slightly greater than 1 for most crops samples. The availability of radionuclides in the farm crops showed a possibility of food chain contamination. This study contributes to environmental radiation assessment and public health awareness by providing radiological data and associated soil to plant transfer in an agricultural setting. A continuous monitoring of NORMs in agricultural setting is recommended to ensure radiological safety and to protect public health from undue exposure to natural radionuclides.