Abstract:

A study of the natural external background radiation in areas affected by Naturally Occurring Radioactive Materials (NORM) has been performed in the Kingdom of Bahrain. It is known that the extraction of oil and gas enhances NORM leading to higher radiation levels. Awali and Riffa Views residential areas are located in the center of the Kingdom of Bahrain. These areas characterize by presence of extensive oil and gas operations and transportations. Awali and Riffa Views have therefore been selected as experimental areas. Two more areas namely; Isa Town and AL-Budaiya Village have been also studied in this work. Such areas, since no industrial activities are present, are expected to have natural background radiation that is not affected by such activities. A hand-held Colibri Very Low Dose (VLD) radiation survey meter with built-in GPS has been used to measure and map the natural external background radiation for the four studied areas. The meter’s GPS has been enabled and radiation measurements have been acquired manually at a distance of every 300 meters intervals and at height of one meter above the ground. Mapping of the radiation profiles of the studied areas has been performed using Google Map Macro online application. The lowest radiation dose rate acquired has been 0.02 µSv/h acquired in Isa Town while the highest has been 0.37 µSv/h occurred in Awali. It has also been found that the mean annual equivalent doses of Isa Town, Al-Budaiya, Awali and Riffa Views; 0.70 ± 0.26 mSv/y, 0.79 ± 0.35 mSv/y, 2.07± 0.66 mSv/y and 1.37 ± 0.44 mSv/y respectively. The radiation exposures in the experimental areas exceeded the maximum permissible limit 1 mSv/y as recommended by ICRP-60. Particularly in south and southwestern Awali in which the mean annual equivalent dose has reached up to 2.80 ± 0.79 mSv/y. High radiation levels in Awali and Riffa Views could be regarded to the presence of extensive oil and gas operation and installations in these areas.