Assessment of radiological hazards due to soil and building materials used in Mirpur Azad Kashmir; Pakistan

Background: Health hazards associated with exposure due to the natural radioactivity which is a part of our physical environment are of great concern. In order to assess the risks associated with exposure due to the natural radioactivity in soil and building materials, extensive studies have been carried out all over the world. The most commonly encountered radionuclide's are U-238, Th-232, their decay products and K-40. Materials and Methods: In order to study the concentration of these radionuclides soil, sand, gravel aggregates, bricks and marble, samples were collected from different sites and local suppliers of the district Mirpur, Azad Kashmir (Pakistan). Ra-226, Th-232, and K-40 activities in the collected samples were measured using HPGe detector. The measured specific radioactivity concentration of Ra-226, Th-232 and K-40 in the studied samples ranged from 10 +/- 1 to 47 +/- 2, 18 +/- 1 to 75 +/- 4 and 40 +/- 3 to 683 +/- 3 Bq. kg(-1), respectively. Results: From the measured activity concentration, radium equivalent activity, external and internal hazard indices, gamma and alpha indices, terrestrial absorbed dose and annual effective dose were calculated. Maximum value of radium equivalent activity of 197.1 +/- 9 Bq. kg(-1) was observed in soil sample whereas minimum value of 45.9 +/- 2 Bq. kg(-1) was found in gravel aggregates. Relatively higher mean values of hazard indices were found in brick samples. Annual effective dose varied from 0.06 +/- 0.01 to 0.47 +/- 0.02 mSv. y(-1). Conclusion: Current values of annual effective dose, radium equivalent activity and hazard indices have been found to be within the recommended limits. Iran. J. Radiat. Res., 2011; 9(2): 77-87