One of the three goals of the United Nations for sustainable food security is to ensure that all people have access to sufficient, nutritionally adequate, and safe food. The south-west area of Nigeria especially Osun State is home to some of the most important minerals, which include bitumen, gold, kaolin, salt limestone, tantalite, coal and phosphate. As a result of the mineral occurrence, some parts of Osun State have become associated with significant levels of natural radioactivity. The exploration and exploitation of these minerals are known to have enormous consequences on the environment. This work is to measure the baseline radioactivity levels in some major food crops in Osun State and hence predict the potential radiological health effects. The study area (Osun State) has a total land mass of about 12820 km2, with a projected population of 5.1 million inhabitants. Osun State lies within latitudes 07o00 N and 08o25 N and longitudes 04o00 E and 05o11 E. Maize, Yam and cassava tubers that constitute the major food nutritive requirements were collected directly across farmlands in the State. The sampling locations were purposely chosen by considering the possibility of mineral resources, water resources, industry and farmlands. In order to have a total coverage of the study area, Osun State was divided into eight zones comprising the thirty local government areas in the State. Maize, yam and cassava were dried at room temperature until a constant weight was achieved. They were ground, homogenized and 250 g sealed in 1-liter Marinelli beaker and kept for 28 days in order to attain secular equilibrium before the gamma counting. The activity concentrations of Ra-226, Th-232, and K-40 were determined in the food samples using γ-ray spectrometry in the Centre for Energy Research and Development, Obafemi Awolowo University, Ile-Ife. The mean activity concentration of Ra-226, Th-232 and K-40 for yam were 1.72 ± 0.10 Bqkg-1, 2.24 ± 0.21 Bqkg-1 and 37.84 ± 2.40 Bqkg-1 respectively. The content of the radionuclides in maize gave a mean value of 2.49 ± 0.48 Bqkg-1 for Ra-226, 2.12 ± 0.06 Bqkg-1 for Th-232 and for K-40, the mean value is 30.92 ± 2.15 Bqkg-1 . The mean specific radionuclide concentrations in cassava is 2.00 ± 0.41 Bqkg-1 for Ra-226, 1.81 ± 0.12 Bqkg-1 for Th-232 and 40.35 ± 3.94 Bqkg-1 for K-40. The committed effective doses were 0.66 µSvy-1 for the consumption of yam, 0.54 µSvy-1 for maize, and 0.66 µSvy-1 for cassava which are lower than the annual dose guideline for the general public. Therefore, the values obtained in this work show that there is no radiological contamination of foodstuffs consumed in Osun State.

The environmental risks connected to the operations of Ife Iron and Steel Nigeria Limited, Ile-Ife, located in Osun State, are examined in this paper. According to reports, the soot and other particles the company's operations release are bad for the locals' health and threaten their sources of income. In order to calculate the absorbed dose, external hazard index, and annual effective dose for the estimation of the potential biological risk/damage to the community, the radionuclides present in soil taken from the area around the industry have been identified and their activity concentrations measured. Gamma ray spectrometry with a NaI detector was used to identify the radionuclides and determine the activity content in soil samples taken from the Fashina community. The absorbed dose rates due to the terrestrial gamma rays at 1.0m above the ground in the study area are in the range of 28.85 nGy/h to 37.05 nGy/h with an average of 33.30 nGy/h which is lower than the world average value of 59 nGy/h. The external hazard index ranges from 0.167 to 0.220 with an average of 0.194 which is less than 1.0. The outdoor annual effective doses are in the range of 0.035 mSv/y to 0.045 mSv/y with an average value of 0.041 mSv/y which is lower compared with the world average value of 0.07 mSv/y. The results show that the annual effective dose from natural radioactivity around the industry has an average value lower than the natural world recommended value.