RADIOLOGICAL ASSESSMENT OF GRAINS, VEGETABLES, FRUITS AND TUBER CROPS CULTIVATED IN OKEMESI TOWNSHIP, EKITI STATE, NIGERIA

Abstract

Exposure to radiation is a natural phenomenon in the human environment. This is received from naturally occurring radionuclides in water, air, soil and food. Ingestion is one of the two major pathways through which these nuclides enter the human systems. Radiological assessment of fruits, vegetables, grains and tuber crops cultivated and consumed in Okemesi township, Ekiti State has been carried out using a 76mm by 76mm lead-shielded Sodium Iodide detector (NaI(Tl)) located at the Centre for Energy, Research and Development (CERD), Obafemi Awolowo University, Ile-Ife, Nigeria. The mean activity concentration of the radionuclides in the food samples was 155.76 ± 14.22 Bqkg-1 for 40K, 8.00 ± 0.24 Bqkg-1 for 238U and 7.39 ± 0.21 Bqkg-1for 232Th.The value obtained for Annual Effective Dose due to intake of the food crops (Ding) ranged from 104.32 to 687 µSv yr-1 while values for Excess Lifetime Cancer Risks (ECLR) ranged from 0.365 t0 2.407. Although the radioactivity levels in the food crops were lower than the world-wide limits, some values obtained for the AED and the ELCR were significantly higher than the recommended limits of UNSCEAR 2000. The rank order of Ding and ELCR in the food types was tubers ? fruits ? vegetables ? grains. Consumption of food cultivated in the area over a long period of time may induce a degree of health risks which should not be overlooked.