This study assessed the radioactivity levels and transfer factor of natural radionuclides around iron and steel smelting company located in Fashina village, Ile-Ife, Osun State, Nigeria. This was with a view to evaluate the exposure rate of the study area, determine the radionuclides present and activity concentration (238U and 232Th and 40K) in the samples and evaluate the soil-to-food transfer ratio of the radionuclides. A portable survey meter with a Global Positioning System (GPS) were used for in-situ investigation and a well-calibrated NaI(Tl) detector system was used for the radioactivity measurement of the samples. A total of 38 samples comprising soil, food and water were collected at the study area (Fashina) and control area (Opa) in Osun state, Nigeria for spectrometry analysis. The soil and food samples were oven dried, pulverized and sieved while water samples were acidified with 10 mL of 11 M HCl per litre to prevent adsorption of radionuclides with the wall of the container. All the samples were then sealed and kept for at least 28 days in radon impermeable cylindrical container so as to reach secular equilibrium. The mean exposure rates in the study area were 0.14 µSv hr-1 and 0.12 µSv hr-1 for the control environment. The mean radioactivity content obtained for 238U, Bq L-1 respectively for 238U, 232Th and 40K in water samples. The transfer factor from soil to food for 238U, 232Th and 40K were calculated from the activity concentrations of soil and food, while the means were 0.73, 0.61, and 0.39 respectively in the study area.

In order to ensure radiation monitoring and protection, an investigation and assessment of radiological risks that may be associated with the consumption of table waters commonly consumed in Ilorin, Nigeria, was carried out. The activity concentration level of 238U, 232Th, and 40K was determined using thallium activated 3˝×3˝ [NaI(TI)] detector connected to ORTEC 456 amplifier. The radiological risks due to the consumption of the samples were then estimated. The highest annual effective dose (AED) values were obtained from VW and the minimum was obtained from UW water. The AED decreases in the order VW>HW>IW>MW>DW>UW. This implies that VW water constitutes more radiation exposure followed by HW, IW, MW, DW, and then UW Water. The values estimated for MW, DW, and UW water were all lower than the world average value of 1 mSv/y and hence pose no serious radiation hazard. While the values estimated for VW, IW, and HW waters were slightly higher than the recommended threshold value, suggesting a possible risk of radiation exposure to customers. The Excess Lifetime Cancer Risks corroborated the findings of the AED, implying that the probability of developing cancer is high for most of the water samples. Since the values of the estimated hazard parameters were mostly higher than the recommended limits for all age groups, it is recommended that public water system should be monitored and efforts should be made to educate and enlighten the public on radiation exposure, its health effects, and remedial actions necessary to reduce radionuclides concentration in drinking water.