Estimation of Naturl Radioactivity Levels in Some Food Spices Commonly Used in Nigeria and Its Radiological Risks

Abstract

A spice is a vegetable substance of indigenous or exotic origin, which has a hot pigment taste that could be used to enhance taste of food or add to food some necessary stimulant ingredients. Knowledge of radioactivity levels in human diet is of particular concern for the estimation of possible radiological hazards to human health. In this study, the radioactivity concentrations of 40K, 238U and 232Th in some selected natural food spices commonly used in Nigeria were determined using gamma spectrometry and the ingested doses via food consumption were also assessed. The average activity concentration of 40K, 238U and 232Th in the samples are 729.85±1.44 Bqkg-1, 2.19±1.38 Bqkg-1 and 46.73±0.27 BqKg-1 respectively. The highest activity concentration of 40K, 238U and 232Th was recorded in Tatashey (2097.17±183) for 40K, Tomatoes (21.90±4.8) for 238U and Red onions (176.38±19) for 232Th. The estimated total annual effective dose received from 40K, 238U and 232Th due to consumption of natural (fresh) spices by the inhabitants of Port Harcourt  ranges from 0.85 to  46.76 µSvy-1and this is far below the average radiation dose of 290 µSvy-1 received per caput worldwide due to ingestion of natural radionuclides in food spices. The results indicate insignificant radiological health hazard to the public due to the consumption of spices via foods. The excess lifetime cancer risk due to ingestion of radionuclide in fresh food spices were evaluated and the values obtained were compared with standards. Based on these results it can be concluded that the foods spices analyzed in this study do not present any significant radiological concerns.