ASSESSMENT OF NATURAL RADIOACTIVITY LEVELS AND RADIATION HAZARDS IN THE TERTIARY INSTITUTIONS IN MINNA, NIGER STATE, NIGERIA.

Abstract

Activity concentrations of natural radionuclides in 30 surface soil samples collected across the three campuses of the two tertiary institutions in Minna, Niger State, Nigeria, were studied and evaluated. This survey was carried out using gamma spectrometric technique which employs NaI(Tl) gamma detector at the Center for Energy Research and Training (CERT), Ahmadu Bello University, Zaria, Nigeria. The mean values for the activity of 226Ra, 232Th and 40K were found to be 7.8±1.3Bqkg-1, 29.4±0.9Bqkg-1 and 229.4±1.8Bqkg-1 respectively. The activity profile of the primordial radionuclides in the soil samples investigated showed the existence of low level activity across the three campuses. The mean value of the annual effective dose equivalent obtained from this study is 0.04mSvyr-1, with mean external hazard index of 0.2. These average values fall within the internationally provided safety range for outdoor radiation exposure. The values obtained from this investigation for all the radiation parameters for the studied soil samples showed that none of the campuses investigated pose any significant radiological threat to the public.