PILOT STUDY OF NATURAL RADIOACTIVITV IN VEGETABLES IN SE,LECTEDLOCATIONS IN ONDO STATE, NIGERIA.

Abstract

The activity concentrations of 40K, 238U and 232Th in some vegetables commonly consumed in Jegele, Idanre and Agbabu have been measured using the gamma ray spectrometer consisting of a lead shielded 76mm by 76mm Nal (Tl) detector crystal coupled to a Canberra series 10 plus multichannel analyzer. Preset counting time of 10 hours (36,000s) was used for each sample. Results showed that the concentrations of radionuclides varied from one location to another. The highest radioactivity concentration of 2459.73Bqkg-', 97.57Bqkg-' and 1844Bqkg-1 4oK, 21l!U and 232Th, respectively was obtained from Talium Triangulare. Talium Triangulare and African Spinach respectively all in Idanre. The lowest concentration of 721.86Bqki', 236Bqkg-'and 623Bqkg-140K, 238U and 232Th respectively was obtained from Telfairia Occidentalis, Solanium Macncarpon and Corchorous Olitorious in Jegele and Agbabu. The equivalent dose rates due to intake of the vegetables were determined. The mean effective dose equivalent for Jegele, ldanre and Agbabu were O.59mSvyrl, 0.73mSvyr" and O.64mSvyrl. These translate to collective doses of 2.95x102manSvyr-l, :1.46xlO'manSvYI--1 and 1.28xlOimanSvyr'I for Jegele, Idanre and Agbabu respectively. All these values are lower than the recommended 2.4mSvyr-' (UNCEAR, ] 993) for normal background. The results presented here serve as reference for future radioactivity monitoring especially in Agbabu after the scheduled exploitation of the bitumen.