Indoor risk assessment of radon gas in the science college buildings-University of Mustansiriyah using RAD-7 detector

Ali A Ridha

doi:10.30723/ijp.v13i27.268

Abstract

In the present work, a set of indoor Radon concentration measurements was carried out in a number of rooms and buildings of Science College in the University of Mustansiriyah for the first time in Iraq using RAD-7 detector which is an active method for short time measuring compared with the passive method in solid state nuclear track detectors (SSNTD's). The results show that, the Radon concentrations values vary from 9.85±1.7 Bq.m-3 to 94.21±34.7 Bq.m-3 with an average value 53.64±26 Bq.m-3 which is lower than the recommended action level 200-300 Bq/m3 [ICRP, 2009].The values of the annual effective dose (A.E.D) vary from 0.25 mSv/y to 2.38 mSv/y, with an average value 1.46±0.67 mSv/y which is lower than the recommended the range 3-10 mSv/y [ICRP, 1993]. While the values of lung cancer cases per year per million person vary from 4.50 per million person to 42.84 per million person with an average value 24.35±12 per million person which is lower than the recommended range 170-230 per million person [ICRP, 1993].The values of the potential alpha energy concentration were found to vary from 10.18 mWL to 1.06 mWL, with an average value 5.79±2.8 mWL which is lower than the recommended value of 53.33 mWL given by [UNSCEAR, 1993].

Highlights

There are several different isotopes of Radon, the one that is of greatest concern as a potential human health threat is Radon (Rn222), where Rn-222 gas is formed naturally during a chain of radioactive disintegration reactions
The highest value was found in the storage room presented in the ground floor of the physics department which was equal to 94.21±34.7 Bq/m3, while the lowest value was found in reporter room presented in the third floor of the biology department which was equal to 9.85±1.7 Bq/m3, with an average value of 53.64±26 Bq/m3, which is less than the lower limit of the recommended action level of ICRP, 2009 (200- 300 Bq/m3) [9]. 2
The highest value again found in the storage room presented in the ground floor of the physics department which was equal to 2.38 mSv/y, while the lowest value was found in reporter room presented in the third floor of the biology department which was equal to 0.25 mSv/y, with an average value of 1.46±0.67 mSv/y

Summary

Introduction

There are several different isotopes of Radon, the one that is of greatest concern as a potential human health threat is Radon (Rn222), where Rn-222 gas is formed naturally during a chain of radioactive disintegration reactions. Some of the peculiarities of workplaces are: (a) multistoried buildings with large entrance hall; (b) presence of air conditioning or forced ventilation; (c) widespread use of ground floor or basements; (d) high probability of finding elevated temperatures and high levels of humidity, dust and aerosols Such workplace characteristics might result in large spatial and time variations of Radon, requiring an appropriate monitoring strategy [2]. As far as human dwellings are concerned the possible enhanced risk could be expected only in a rather small faction of homes depending essentially on the building materials ventilation features and soil characteristics These factors are directly responsible for enhanced input and subsequent stagnation of Rn222 in indoor air [3].

Indoor radon concentration

Lung cancer cases per year per million person

Deanery building central heatsink storeroom