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Determination of Radon Concentration and the Annual Effective Dose in Karbala University Campus, Karbala, Iraq

Abbas J. Al-saadi

Karbala Journal of Medicine مجلة كربلاء الطبية
ISSN: 19905483 Year: 2013 Volume: 6 Issue: 1 Pages: 1591-1599
Publisher: Kerbala University جامعة كربلاء

Abstract

determination of radon gas concentrations in multistory buildings and outdoor in the Karbala University campus (Karbala-Iraq) were carried out by using Solid-state nuclear track detector (CR-39).The detectors were distributed over 20places(14 indoor and others outdoor). The area of the study includes College of Medicine, College of Dentistry, College of Pharmacy, College of Sciences, student's residence and the Central Library. The dosimetric measurements were made over a period of 3 months.(from 15 September to 14 December 2012). After exposure, the detectors were etched in a (NaOH) solution of normality (6.25 N) at temperature of 70 oC for 3 hours. The tracks were counted by the microscope track-counting system. The indoor radon gas concentrations were found to vary from 41.881 ± 2.463Bq/m3 to 95.642 ± 5.730 Bq/m3 with an average value and standard deviation of 70.358 Bq/m3and14.367Bq/m3 respectively. The outdoor air radon concentrations are ranged from 25.134 ± 1.783Bq/m3 to 28.594 ± 2.854Bq/m3 with an average value of 26.974 Bq/m3and standard deviation 1.155 Bq/m3. In the survey of radon concentration in multistory buildings was observed that the upper floor have lower radon concentration than the ground floor. It has found that, in general, the radon level in lower floors is higher than that in upper ones in all buildings. The annual effective dose to the population from the inhalation of radon was also estimated and this varied from 1.056 ± 0.062mSv/ y to 2.412 ± 0.144mSv/ y, with an average of1.774 mSv/y and standard deviation is 0.362mSv/ y. The ratio between indoor and outdoor radon concentration (mean value) in this study was about 3.The radon concentrations were found to be lower than the higher level recommended by ICRP ( 200 Bq/m3) and thus are within safe limits.

Keywords

Natural radioactivity --- Radon --- indoor air --- Radon outdoor air --- Annual effective dose --- CR-39track detector --- environment --- Karbala University