The activity concentrations of 226Ra, 232Th and 40K in
fifty granite samples collected from five different quarry industries in Ondo State,
Nigeria, were determined using gamma-ray spectrometry. The mean activity concentrations
for each industry ranged from 16.7(6.4) to 85.4(23.0), 62.4(10.1) to 113.6(7.6), and
1315(136) to 1551(84) Bq.kg-1 for 226Ra, 232Th and
40K, respectively. The values in parenthesis are the standard deviations.
When compared with results from some parts of the world, the 226Ra and
232Th 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 the
radiological hazards associated with the use of the granites examined in this study as
building material are within the acceptable limit.