The assessment of the radiation hazard indices due to uranium and thorium in some Egyptian environmental matrices

摘要

The estimation of exposures of humans to the various sources of radiation is important. Instrumental neutron activation analysis has been used for the determination of uranium and thorium in environmental samples such as Toshki soil, Aswan iron ore, gold vein deposits and phosphate samples from Upper Egypt. The specific activities due to U-238 and Th-232 have been measured and the radiation hazard to the workers, the Radium equivalent activities, representative level index and dose rates were also estimated. The lowest external gamma-radiation dose received by the workers is 33.15 +/- 6.06 mu Sv y(-1) which comes from gold samples and the highest one was 315.65 +/- 7.98 mu Sv y(-1) which comes from phosphate samples which is far below the worldwide allowed dose of 20 mSv y(-1) for workers (ICRP-60 1990).