RADIOACTIVITY CONCENTRATION AND DOSE ASSESSMENT OF SOIL SAMPLES IN CEMENT FACTORY AND ENVIRONS IN OGUN STATE, NIGERIA

Abstract

The main natural radioactive materials that contribute externally and internally to man and his environs are radionuclides emanating from gamma series of 238U, 232Th, as well as 40K isotope, alpha and beta sources. Also, human activities such as mining and milling of uranium and phosphate, tobacco smoking, oil exploration, air transportation, coal-fired power station, and so on can trigger The technologically Enhanced Naturally Occurring Radioactive Materials (TENORMs). It is imperative to monitor the terrestrial background radiation of radionuclides emanating from these sources in order maintain a safe environment for humans. This study measured the activity concentration of 238U, 40K and 232Th in soil samples from cement factory and environs using the NaI(TI) detector, in three zones in Ogun State, Nigeria. The activity concentrations obtained for the three zones are in the order 238U < 232Th < 40K respectively. The radiological parameters estimated from the activity measured were all within the recommended permissive limit except for the annual gonadal doses from the cement factory and its environs, which are higher than the global standard by the factors of 1.03 and 1.07 respectively. This study therefore concludes that people living and working in these areas might be exposed to high radiation burden as a result of cumulative effect of the emission from the factory.