Radon level and radon effective dose rate determination using CR-39 in public hospitals Iraq1 Kurdistan Region

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1 Volume 2 Issue1 pp April ISSN Radon level and radon effective dose rate determination using CR-39 in public hospitals Iraq1 Kurdistan Region Zakariya A. Hussein (1)*, Mohamad S. Jaafar (1), and Asaad H. Ismail (2)* (1) Radiation and Medical Physics, School of Physics, Universiti Sains Malaysia, 118, Pulau Penang, Malaysia (2) Medical Physics, Physics Department, Education College, Salahaddin University-Erbil, 442, Iraqi Kurdistan, IRAQ *Corresponding authors: zekishtayin@yahoo.com Abstract Environmental radiation exists as a consequence of cosmic, terrestrial and manmade sources. The measurements of radon concentration inside 8 public hospitals in the three main governorates: Erbil, Duhok and Sulaymaniya in Iraqi Kurdistan Region, during two season spring and autumn by using CR-39 nuclear track detectors. The highest average radon concentration and annual effective dose was found in the Shaheed Dr.Aso hospital (Sulaymaniy a) in autumn season (16.92±4.63Bq.m -3, 2.47±.5 msv/y ) respectively, and the lowest was found in the Erbil Teaching hospital (Erbil) in spring season (48.2±3.77 Bq.m -3, 48.2±3.77 msv/y ) respectively, this depended on the geological formation, type of building material, ventilation rate and the floor level. Therefore, the results showed that the average radon concentration and annual effective dose decreases gradually as the floor level increases. The highest and lowest of annual effective dose was found in ground and second floor, respectively. Comparing these values to the Ionizing Radiation Regulations (IRR) values which indicate that the estimated effective doses for workers in these hospitals are less than the average overall radon dose. Key words: CR-39NTDs, Indoor radon, lung cancer, ventilation and hospitals 1. Introduction Inhalation of radon and its decay products is responsible of about half of the annual average effective dose received by the human due to natural sources of radiation [1]. Outdoor radon do not represent a significant health hazard because high concentrations are never reached. However, it becomes a problem when released into a closed or poorly ventilated enclosures like dwellings, buildings and also caves and mines. Indoor concentrations of radon and its short-lived progeny depend on several factors mainly related with the entry or production rate from various sources and the ventilation rate [2]. Radon ( 222 Rn) is a radioactive noble gas emitted by the decay of 226 Ra, an element of the 238 U decay series. Radon-222 decays into a series of other radioactive elements, of which 214 Po and 218 Po are the most significant, as they contribute the majority of radiation dose when inhaled. Following a number of decay series, 218 Po transforms into 21 Po and it decays into stable 26 Pb. The 222 Rn and its decay products are reported as major causes of lung cancer [3-4]. Assessment of health effects due to exposure to ionizing radiation from natural sources requires knowledge of its distribution in the environment. The estimated global average annual dose of the population receiving natural radiation equals 2.4 msv [5]. It is well established that the inhalation of radon ( 222 Rn) and mainly its radioactive decay products, contributes more than 5% of the total radiation dose to the world population from natural sources [6]. The main natural sources of indoor radon are soil, building materials (sand, rocks, cement, etc.), water born transport, natural energy sources like (gas, coal, etc.) which contain traces of U-238 [7-8]. The half-life of radon, 3.8 days, is long enough for part of it to diffuse from the indoor radon sources to the inside of the room [9]. Therefore, in the present study, beside of measure indoor radon concentration and annual effective dose, we have measure most of important that related to estimate a risks of inhalation of radon gas by the workers inside the hospitals. As well as, and to find variation in radon concentration for three floors ground, first, and second. 2. Materials and methods Iraqi Kurdistan region consist of three main governorates; Erbil, Duhok and Sulaymaniya. These

2 Volume 2 Issue1 pp April ISSN areas are different from each other geographical location is shown in Fig. 1. Passive radon dosimeter geometry is a closed-opened chamber into which radon diffuses, and it has been calibrated by Ismail and Jaafar [9]. The schematic diagram of the chamber is shown in Fig. 2. The technique used in this survey is based on CR- 39NTDs (Moulding, UK, manufactures the detectors), it has area of cm 2 which is fixed by double-stick tape at the bottom of the dosimeter. In the cover there is a hole covered with a 5-mm thick soft sponge. The design of the chamber ensures that all aerosols and radon decay products are deposited on the soft sponge from the outside and that only radon gas. The design of the chamber ensures that the aerosol particles and radon decay products are deposited on the sponge from outside and only radon, among other gases, diffuses through it to the sensitive volume of the chamber. The dosimeters were distributed inside 8 public hospitals in three main regions (Erbil, Duhok and Sulaymaniya) in Iraqi Kurdistan region, in each hospital distributed on three floors (ground, first and second). Nuclear track detector type CR-39 (CR-39NTDs) used to measure track density of alpha particles that emitted from radon and its progeny. During for two seasons spring and autumn,144 pair of exposure chambers (opened -closed chamber) equipped with 288 pieces of CR-39NTDs installed inside 72 rooms for three floors ; 3 rooms in each floor, on the top about 2m above the floor. After for each season (9 day) of exposure, exposed detectors etched in 6N NaOH at 7 C for 1 h. The counting of alpha damage tracks was done using an optical microscope with a magnification of 4X was used. 3- Results and discussion Average value of indoor radon concentration (C Rn ) and annual effective dose (H E ) inside public hospitals in Iraqi Kurdistan Region for two seasons spring and autumn summarized in Table 1. The highest indoor radon concentration and annual effective dose was found in autumn season in Shahid Dr.Aso hospital (16.92±4.63 Bq.m -3, 2.47±.5 msv/y ) respectively, and lowest was found in spring season in Erbil Teaching hospital ( 48.2±3.77 Bq.m -3,1.54±.15 msv/y ) respectively, as shown in Fig.3 and Fig.4. However, it was observed that the values are much lower than the action levels recommended by the International Commission on Radiological Protection (ICRP) [4]. The seasonal variation of radon levels could be attributed to the meteorological conditions, since in autumn, these dwellings were poorly ventilated to save energy but they had good ventilation in spring time. This refers to the different building material, ventilation rate, and the geological formation. The geological formation of Erbil governorate different than the geological formation of Duhok and Sulaymaniya. More details about geological formation are listed in Table 2 [1]. Table 3 shows the maximum and minimum radon concentration and annual effective dose for each level. The highest average radon concentration was found in ground floor in autumn season in the Shaheed Dr.Aso hospital ( ±1.94 Bq. m -3 ) and lowest was found in second floor in spring season in the Rizgary Teaching hospital (47.4±2.61 Bq. m -3 ), as shown in Fig.5. The combination relation of annual effective dose in different floors in spring and autumn seasons shows in Fig.6. Average indoor radon concentration decreases as the floor level increases, this due to the reduced effect of radon exhalations from the ground. This variation may be attributed to how close or how far the floor is from ground since soil represents the main source of indoor radon. In addition, many other reasons such as the fact that upper floors are better ventilated than lower floors that are exposed to dust and other forms of contaminations. 4- Conclusion Indoor radon concentrations have been measured inside public hospitals in Iraqi Kurdistan region in two seasons spring and autumn. Floor levels and geological formation of the Iraqi Kurdistan hospitals affect on the concentrations of indoor radon and its progeny locations of the selected hospitals had different geological formation and located in three main governorates: Erbil, Duhok and Sulaymaniya. The effect of the geological formation on indoor radon concentration and this has been investigated. The highest radon concentration was found in autumn in the Shaheed Dr. Aso hospital (Sulaymaniya city: mountain region) and lowest in spring in the Erbil Teaching hospital (Erbil city: plains region). The average radon concentration and annual effective dose decreases gradually as the floor level increases. The highest and lowest of annual effective dose was found in ground and second floor, respectively. Acknowledgement The authors deeply thank all the staffs and patients in selected hospitals in Iraqi Kurdistan for their information and a good cooperation.

3 Volume 2 Issue1 pp April ISSN Reference 1- United Nations Scientific Committee on the effects of Atomic Radiation UNSCEAR 2 Report to the General Assembly with Annexes, New York, vol. 1: Sources, United Nations Publication, Sales No. E..IX.4. New York, Commission Recommendation of 21 February 199 on the protection of the public against indoor exposure to radon (9/143/EURATOM). 3- International Commission on Radiation Protection (ICRP), Lung Cancer Risk from Indoor Exposure to Radon Daugthers Oxford. ICRP Publication. 5 17(1). 4- International Commission on Radiological Protection ICRP, (1984). Non-stochastic Effects of Irradiation. ICRP Publication 41. Ann. ICRP Ismail A H and Jaafar M S. (211). Interaction of low-intensity nuclear radiation dose with the human blood: Using the new technique of CR- 39NTDs for an in vitro study. Applied Radiation and Isotopes. 69(3) p Ismail A H and Jaafar M S. (21). Indoor radon concentration and its health risks in selected locations in Iraqi Kurdistan using CR- 39 NTDs. The 4 th International conference on Bioinformations and Biomedical Engineering (icbbe 21) June. Chengdu-Chaina. 21 IEEE 7-7- Banman, A., Hervat, D.J., Lokobauer, N., In Vahra, K.J. et al. (Eds.), Natural Radiation Environment. WillyRastern Ltd, New Delhi, p Bigu, J., Vandrish, G., Environ. Monit. Assess 6, Steinhausler, F., Radon in the human environment a global approach. Proceedings of the Eighth IRPA Congress, Montreal, Canada, pp Kamal H. K. and Ali M.S.,(24). Geological formation in Iraqi Kurdistan : (KAJ) Kurdistan Academicians Journal, 4(1) part A p Table (1) Indoor Radon Concertration and Annual Effective dose inside hospitals in Iraqi Kurdistan Region. Annual Effective Dose Regions Hospital Radon Concentration (Bq/ m 3 ) (msv/y) Erbil Duhok Sulaymaniya Rizgary 54.4± ± ± ±.11 Emergency west 52.3± ± ± ±.8 Erbil Teaching 48.2± ± ± ±.15 Paediatric 6.38± ± ± ±.13 Azadi Teaching 65.36± ± ± ±.5 Emergency Teaching 59.5± ± ± ±.27 Shahid Dr. Aso 71.9± ± ± ±.12 Shorsh General 67.56± ± ± ±.5

4 Volume 2 Issue1 pp April ISSN Table 2: Geological formation of Iraqi Kurdistan region as related to the case study Regions Hospital Equilibrium Factor (F) Building materials Rizgary Region consists of the plains and hills. It consists of sandstone, limestone and shale Emergency west Erbil clay brick, cement Erbil Teaching concrete, gypsum Duhok Sulaymaniya Paediatric Azadi Teaching Emergency Teaching Shahid Dr. Aso Shorsh General Region consists of the plains, sediment logical and mountains. It consists of marly limestone, calcarenite shale, sandly limestone and conglomerate Region consists of the Rocky Mountains and valleys. It consists of rocks, limestone, conglomerate, biogenic limestone, pebbly, calcarenite and sandstone and gypsum bord clay brick slimestone bricks, cement gypsum and gypsum bord clay brick slimestone bricks and cement concrete gypsum Hospitals Rizgary (Erbil) Azadi Teaching (Duhok) Shahid Dr. Aso (Sulaymany) Table (3) Indoor radon concentration and Annual effective dose for different floors in inside hospitals in Iraqi Kurdistan Region. Levels Radon Concentration (Bq/m3) Annual Effective dose (msv/y) Ground 59.34±2.23 First 55.39± ± ± ± ± ± ±.3 Second 47.4± ± ± ±.5 Ground 7.22± ± ± ±.11 First 65.79± ± ± ±.18 Second 6.9± ± ± ±.6 Ground 75.53± ± ± ±.6 First 7.82± ± ± ±.5 Second 66.94± ± ± ±.1

5 Volume 2 Issue1 pp April ISSN Sponge membrane Hole 1cm CR-39 h=7cm Fig.1: Sketch Map of the area under study (Kurdistan Region) r= =3cm Fig.2: Schematic diagram of the optimum Radon. Radon Concentration (Bq/m3) Hospitals Fig. (3) Measurement of indoor radon concentration in spring and autumn inside public hospitals in Iraqi Kurdistan Region

6 Volume 2 Issue1 pp April ISSN Annual Effective dose (msv/y) Hospitals Fig. (4) Measurement of Annual effective dose in spring and autumn inside public hospitals in Iraqi Kurdistan Region Radon Concentration (Bq/m3) Ground First Second Floors Fig. (5) Variation of Radon Concentration with floor levels in spring and autumn seasons in Shaheed Dr. Aso hospital

7 Volume 2 Issue1 pp April ISSN Annual Effective dose (msv/y) Ground First Second Floors Fig. (6) Variation of Annual Effective dose with floor level in spring and autumn seasons in Shaheed Dr. Aso hospital