Natural radioactivity and associated radiation hazards of some commonly used building materials in southwest Nigeria

Abstract

The activity concentrations of primordial radionuclides ( 40 K, 226 Ra and 232 Th) in five different types of commonly used building materials in southwest Nigeria were measured using a low-background NaI(Tl) detector coupled to an IBM-compatible multichannel analyzer. The highest mean concentration of 40 K, which was 887.5 ± 101.3 Bq.kg -1 , was obtained in gravel. Also, the highest mean concentrations of 226 Ra and 232 Th were obtained, respectively, in sand and brick samples. The lowest mean concentrations of 40 K, 226 Ra and 232 Th, respectively, were obtained in brick and cement sample. The annual gonadal effective dose (AGED) and other radiological parameters were estimated from the activity concentrations of the radionuclides. The highest mean values of the AGED and radium equivalent activity concentration obtained were 359.1 μSv.y -1 and 110.9 Bq.kg -1 , respectively. All these radiological parameters were below the maximum permissible levels recommended for safe use of materials in building construction. It can therefore be concluded that these materials do not pose any radiological hazard to the dwellers of buildings constructed with them.