Gamma spectroscopic analysis and associated radiation hazards of building materials used in Egypt

Radiation exposure of the population can be increased appreciably by the use of building materials containing above-normal levels of naturally occurring radionuclides of terrestrial origin. Using gamma-ray spectrometry, the natural radioactivity levels of 55 samples of natural and manufactured Egyptian building materials have been investigated. The samples were collected from local market and construction sites. From the measured gamma-ray spectra, activity concentrations were determined. The activities were in the ranges 11.7-35.6, 12.4-55.2 and 60-350 Bq kg(-1) for (226)Ra, (232)Th and (40)K, respectively. The activities are compared with available reported data from other countries and with the world average value for soils. The radium equivalent activity Ra(eq), the external hazard index H(ex) and the absorbed dose rate in air D in each sample was evaluated to assess the radiation hazard for people living in dwellings made of the materials studied. All building materials have shown Ra(eq) (range from 37.76 to 116.87 Bq kg(-1)) lower than the limit of 370 Bq kg(-1) adopted by the Organization for Economic Cooperation and Development (OECD). The absorbed dose rate in indoor air is lower than the international recommended value of 55 nGy h(-1) for all test samples. All the materials examined are acceptable for use as building materials as defined by the OECD criterion.