Soil –plant transfer factors of radionuclide in cassava (Manihot esculenta) around a cement factory in Kogi State, Nigeria

Abstract

Mathematical models are typically used to predict how naturally occurring radionuclides migrate from soil to plants. A transfer factor (TF) is the ratio of radionuclide concentration (Bq kg−1) of plant to soil in dry weight. This research aimed at determining the soil to plant transfer factor of radionuclide, in order to access the level of migration of natural radionuclide from soil to a selected cultivated crop (cassava), due to cement production activity around a cement factory. Soil and cultivated plant samples were collected randomly at different locations around the factory. The collected samples were analyzed using NaI (Tl) gamma (γ) spectroscopy. The average transfer factor (TF) from soil to plant was found to be 0.428, 0.531 and 0.398 for 226Ra, 232Th and 40K, respectively. The TF indicates that about 42.8%, 53.1% and 39.8% of 226Ra, 232Th and 40K, respectively, were transferred from soil to cassava and varies in the order of 232Th (0531) > 226Ra (0.428) and 40K (0.398). All the transfer factors were below the world standard of unity. There exists a positive Pearson correlation among the three radionuclides in the soil and plant samples. The three radionuclides were detected in soil and food samples, and a positive correlation between them suggests that they originated from the same source for each environmental matrix. The results determined the value of TF of soil to cassava (Manihot esculenta) is at a safe level to the farmland around the cement factory and have no immediate radiological health implications due to cement production.