Radon Exhalation and radiological impact of building materials containing fly ASH (original) (raw)

The knowledge of the natural radioactivity of building materials is important for the determination of population exposure to radiations, as most of the residents spend about 80% of their time indoors, In controlling the natural radiation exposure for the residents of dwellings, it is necessary to detennine the levels of natllHI1radioactivity and radon exhalation rate from building materials, A knowledge 0[' Hldioactivity present in construction materials helps to (n) assess the possible radiological hazards to human health and (b) develop the standards and guidelines for use and management ofthe,~materials. The pr~s~nt study deals with a total of 71 samples of II dilTerent commonly used structural and covering building materials in which, six types of covering/decorative building materials (marble, granite, mosaic stone, tiles, limestone and lime powder, where, most of them are imported from different countries); four types of structural building materials (cement, brick, sand and stone) and one by-product of coal-fired power plants (fly ash) were collected from varions manufactnrers ami suppliers to measure the natural radioactivity due to the presence of :!:!uRa, 2J2.yhand 4rx.. The measurements were carried ont using gamma-ray spectrometry with an HPGe detector. The radon exhalation rate was measured by hermetically closing the sample in a contain~r and following the radon activity growth as a function of time. The specific activities of the different building materials srudied varied from 46.770101.91 to 117.770106.16 Bq.kg"l, 52.36:102.33 to 157.32"=8.55 Bq.k{l and 668,77="11.50 to 1463.3tli22.77 Bq.kg"1for 22liRa, m'lb and 4~, respectively. The results show that the lowest mean values of the specific activity of 226Ra,232Thand 4~K ar~46.77:101.91 (marble), 52.36:102.33 (marble) and 66~.77"=11.50 Bq.kg,1 (limestone), respectively while the highest mean values of the specific activity of the same radionuclides are 117.77"=6.16, 157.32"=8.55 and 1463.30"=22.77 8q.kg"l, respectively measured in fly ash. The measured activity concentrations for this radionuelide were compared with the reported data of other countries and with the typical world values. The average values of radon exhalution nlte of the studied materials varied li-om 0.010 to 0.044 Bq.kg'l.h'l. This study revealed that all the M f'itil'lltesis