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摘要
Common building materials collected from Aden, Yemen were analyzed for the natural radioactivity of Ra-226, Th-232 and K-40 using gamma-ray spectroscopy. The average activity concentrations of Ra-226, Th-232 and K-40 in the studied building materials range from 20.78 to 68.6, from 15.48 to 95.08 and from 116.7 to 2636.68 Bq kg(-1), respectively. The measured activity concentrations for these radionuclides were compared with chemical data obtained by XRF analysis and with the reported data of other countries and compared also with the worldwide average activities. The radium equivalent activities of the studied samples that range from 69 to 369.3 Bq kg(-1) are below the internationally accepted values (370 Bq kg(-1)), except those of Hapach hard rock (407.6 Bq kg(-1)). The external and internal hazard indices that range from 0.2 to 1.1 and from 03 to 1.3, respectively, of all analyzed building materials are less than unity, except those of Hapach hard rock (H-ex = 1.1 and H-in = 1.3) and hard rock of Crater (H-in = 1.2). The mean values of indoor absorbed dose rate for all building materials range from 30.7 to 199.8 nGy h(-1) except those for cement, macadam, hard rock of Habaylin and hard rock of Abyan which are higher than the world population-weighted average of 59 nGy h(-1) and the total annual effective dose values of building materials that range from 0.15 to 0.98 mSv y(-1) are lower than 1 mSv y(-1) except for the samples of Hapach hard rock (0.98 mSv y-1) which have the closed value (the limit of accepted value (1 mSv y(-1)) reported in the UNSCEAR (2000)). The study shows that the measured radioactivity for building materials does not pose as significant source of radiation hazard and is safe for use in the construction of dwellings, while when using Hapach hard rock and hard rock of Crater for construction, their natural radioactivity level should be monitored.
- 出版日期2014-5
