Recent review of natural and artificial background radiation dosimetry studies in Saudi Arabia

This paper includes a review of the natural background radiation of the Kingdom of Saudi Arabia. The review deals with natural radioactivity measurements conducted in the past few decades in the Kingdom. The numerous research works reviewed refer to different materials soils processed building material, terrestrial (dwellings) and mining sites. For the measurements, different experimental techniques were adopted. The highest mean specific activity of U-238, Th-232 and (40) K in soil samples was found to be 39.0, 25.6, and 343.0 Bq/kg, respectively. While the world average values are 33, 45 and 420 Bq/kg, respectively. For building materials, the highest mean values for Ra-226, Th-232 and (40) K were 89, 106 and 773 Bq/kg, respectively. The mean indoor and outdoor dose rates were 455 mu Gy/y (Riyadh City) and 883 mu Gy/y (Al-Khamis City), respectively. For the mining sites the mean values for U-238, Ra-226, Ra-228, gross alpha and gross beta, were 0.12, 0.33, 21, 0.78 and 2.44 Bq/kg, respectively. Based on the available data it is concluded that most of the natural background radiation levels in the measured locations were within acceptable limits, while a few isolated locations showed elevated dose rates. This review suggests that new improved radiological survey methods be employed to cover the entire country, and that areas identified with comparably high dose rates be re-assessed, especially, in dwellings and mining sites.