Health Risk Assessment of Natural Radionuclides Ingestion from Selected Edible Crops in Farmlands Around Limestone Excavation Area in Ewekoro, Ogun State

Abstract

: Natural radionuclides are found in the air, water and soil. They are introduced to the plants through the leaves and absorption of nutrients and water from the soil by the roots. The presence of radionuclides in plants can affect directly humans through the consumption of the plant or indirectly through the food chain. The concentrations of natural radionuclides in some crops from farms around Ewekoro limestone excavation area in Ewekoro town, Ogun State in Nigeria, were determined and the annual committed effective dose to the consumers was also determined. In addition, soil samples from the farms where each crop was planted were collected to determine the transfer factor and the radiological safety of people on the farms. The gamma spectrometry method was used for the analysis. The highest concentrations of ⁴⁰K, ²³⁸U and ²³²Th in crops were 856.13 ± 32.25Bqkg^-1, 35.27 ± 5.91Bqkg^-1 and 13.39 ± 2.75Bqkg^-1 respectively. The average annual committed effective dose of the natural radionuclides to the consumers was calculated to be 0.9214mSvyr^-1, which was below the limit of 1.0mSvyr^-1 recommended globally. The average excess lifetime cancer risk of the radionuclides consumption to the consumers was determined to be 3.225 x , which was below the recommended limit of 1.45 x  and therefore indicated that the ingestion of these radionuclides through the consumption of these crops has no significant radiological health hazard to the consumers. However, the average annual effective dose equivalent of the radionuclides from soils within the investigated farms showed an average value of 0.0458 mSvyr^-1, which was below the limit of 1 mSvyr^-1. Average excess lifetime cancer risk was determined to be 0.1547 x  which was below the recommended limit, indicating that the farmers and the people in the environs were not exposed to radiological health hazards