The activity concentrations of 226Ra, 232Th and 40K infifty granite samples collected from five different quarry industries in Ondo State,Nigeria, were determined using gamma-ray spectrometry. The mean activity concentrationsfor each industry ranged from 16.7(6.4) to 85.4(23.0), 62.4(10.1) to 113.6(7.6), and1315(136) to 1551(84) Bq.kg-1 for 226Ra, 232Th and40K, respectively. The values in parenthesis are the standard deviations.When compared with results from some parts of the world, the 226Ra and232Th contents were lower, whereas the 40K content was similar.Using different approaches to estimate the potential radiological hazard of the samples,the results obtained were below the recommended maximum limits. This shows that theradiological hazards associated with the use of the granites examined in this study asbuilding material are within the acceptable limit.
