DETERMINATION OF ABSORBED DOSE RATE AND EFFECTIVE DOSE EQUIVALENT DUE TO NATURAL RADIONUCLIDE PRESENT IN SOIL IN OYO AND OSUN STATE, SOUTH-WESTERN NIGERIA

ABSTRACT There has been great concern about the health risks associated with exposure to natural radioactivity present in soil, thus in this work, the natural radioactivity contents in surface soil of Oyo and Osun state in South-Western Nigeria; which is commonly used as building material and farming were analyzed. The analysis was carried out by means of gamma ray spectrometry using NaI(TI) scintillation as the detector coupled to PGT, multichannel analyzer 2100R. The radioisotopes identified in the samples of the materials include those of the series headed by 238U and 232Th as well as the singly occurring isotope 40K. The mean activity concentrations of these radionuclides were found to be 23.39±3.20, 19.37±2.60 and 165.14±7.10 Bq/kg for 226Ra, 232Th and 40K respectively. The mean absorbed dose rate, annual effective dose equivalent and the collective effective dose equivalent were determined from the measured activity concentration of the radionuclide respectively. The results obtained are lesser than the requirement for materials used in bulk amounts