Assessment of natural radionuclides in a fertilized farmland in Abeokuta, Nigeria: Implications for environmental radioactivity evaluation and monitoring

In this study, the concentrations of radionuclides were determined for soil samples obtained from a fertilized farm soils in Abeokuta, southwestern Nigeria. On the average, seven soil samples were obtained and keptin a sealed polythene bags. Then later dried and pulverized. Two hundred grams of each of the pulverized samples was held in a standard plastic container and left for about thirty days to allow for secular equilibrium between radium and its progenies. Radionuclides activity concentrations within the collected samples were measured using a calibrated NaI-based gamma-ray spectrometer. The detected natural radioactivity of soil samples are presented and radiological attributes for effective radiological hazards detection and monitoringfor the study location are equally estimated. The results revealed that the specific activity for K-40 radionuclides at location L7 is higher than the world average concentration of 420 Bq/kg. This is not unconnected to the fertilizer within that portion of the farm. However, the estimated radiological attributes in the farmland are relatively lower that the threshold standards, which implies that the soils in the farmland are free of any radiation hazards and pose no threat to farmers and the residents of that area. It is however recommended that organic manure should be used in the farmland rather than fertilizer and routine check on environmental radioactivity of the farmland should be done regularly for adequate monitoring. (paper)