estimated-the-concentration-of-radon-in-drinking-water-in-selected-sam

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________________________________________ Author for correspondence E-mail: anaam_haniyahoo.com Int. J. Chem. Sci.: 144 2016 2095-2104 ISSN 0972-768X www.sadgurupublications.com ESTIMATED THE CONCENTRATION OF RADON IN DRINKING WATER IN SELECTED SAMPLES FROM THE UNIVERSITY OF BABYLON / IRAQ INAAM H. KADHIM a and KHALID H. HATIF b a Department of Physics College of Education for Pure Sciences University of Babylon BABYLON IRAQ b Department of Physics College of Science University of Babylon BABYLON IRAQ ABSTRACT Radon is a radioactive noble gas of a natural origin. It is worthy to carry out the distribution of radon 222 Rn activity concentration and their annual effective dose exposure in drinking water samples from University of Babylon 100 Km south of capital Baghdad. Water samples were collected before and after winter season and analysed using RAD7 connected to a RAD-H 2 O accessory. The measured radon concentration ranges from 0.072 Bq.L -1 in W7 Physical Education to 0.325 Bq.L -1 in W2 Basic Education College with an mean value of 0.183 Bq.L -1 . The measured values of radon concentration are well in the range within the EPA’s Maximum Contaminant Level of 11.1Bq.L -1 . The total annual effective dose resulting from radon in drinking water were 1.74 μSv.y -1 significantly lower than the United Nations Scientific Committee on the Effects of Atomic Radiation UNSCEAR recommended limit for members of the public of 1 mSv.y -1 . It has been chosen this subject of the current study of the importance of water in human life and living and the lack of previous studies in the study area. The measured values for sample water from the study area suggested that the area is safe and there is no significant threat to the population as per as radon concentration is concerned. Key words: Radon concentrations Water Annual effective dose Babylon RAD7 UNSCEAR. INTRODUCTION Radon is a chemical element with symbol Rn and atomic number 86. It is a radioactive colorless odorless tasteless noble gas occurring naturally as an indirect decay product of uranium or thorium. Its most stable isotope 222 Rn has a half-life of 3.8 days 1 . Radon is one of the densest substances that remains a gas under normal conditions. It is also

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I. H. Kadhim and K. H. Hatif: Estimated the Concentration of…. 2096 the only gas under normal conditions that only has radioactive isotopes and is considered a health hazard due to its radioactivity. Intense radioactivity has also hindered chemical studies of radon and only a few compounds are known 2 . Radon is formed as one intermediate step in the normal radioactive decay chains through which thorium and uranium slowly decay into lead. Thorium and uranium are the two most common radioactive elements on earth they have been around since the earth was formed. Their naturally occurring isotopes have very long half-lives on the order of billions of years. Thorium and uranium their decay product radium and its decay product radon will therefore continue to occur for tens of millions of years at almost the same concentrations as they do now. 1 As radon itself decays it produces new radioactive elements called radon daughters. Unlike the gaseous radon itself radon daughters are solids and stick to surfaces such as dust particles in the air. If such contaminated dust is inhaled these particles can stick to the airways of the lung and increase the risk of developing lung cancer. 3 Epidemiological studies have shown a clear link between breathing high concentrations of radon and incidence of lung cancer. 2 Thus radon is considered a significant contaminant that affects indoor air quality worldwide. According to the United States Environmental Protection Agency radon is the second most frequent cause of lung cancer after cigarette smoking causing 21000 lung cancer deaths per year in the United States. About 2900 of these deaths occur among people who have never smoked. While radon is the second most frequent cause of lung cancer it is the number one cause among non-smokers according to EPA estimates. 3 Radon concentration varies widely from place to place Radon mostly appears with the decay chain of the radium and uranium series 222 Rn and marginally with the thorium series 220 Rn. The element emanates naturally from the ground and some building materials all over the world wherever traces of uranium or thorium can be found and particularly in regions with soils containing granite or shale which have a higher concentration of uranium. However not all granitic regions are prone to high emissions of radon. Being a rare gas it usually migrates freely through faults and fragmented soils and may accumulate in caves or water. Owing to its very short half-life four days for 222 Rn radon concentration decreases very quickly when the distance from the production area increases. Radon concentration varies greatly with season and atmospheric conditions 4 . The effects of radon if ingested are similarly unknown although studies have found that its biological half-life ranges from 30-70 minutes with 90 percent removal at 100

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Int. J. Chem. Sci.: 144 2016 2097 minutes. In 1999 National Research Council investigated the issue of radon in drinking water. The risks associated with ingestion was considered almost negligible. 2 Water from underground sources may contain significant amounts of radon depending on the surrounding rock and soil conditions whereas surface sources generally do not. 4 As well as being ingested through drinking water radon is also released from water when temperature is increased pressure is decreased and when water is aerated. Location of the study area The university of Babylon is one of the major Iraqi universities. Located in the province of Babylon 100 Km south of the capital Baghdad on the banks of the Euphrates River. It consists of 20 colleges within three compounds located seven kilometers south of the city of Hillah in Babylon Province at Latitude 32.392754 north longitude 44.398928 east as shown in Fig. 1. The campus was originally the Administrative Institute of Babylon. Later some of the buildings were adopted for use by the medical college of the University of Kufa before being established as a university in its own right in 1991 5 . Fig. 1: Map of University of Babylon 5 EXPERIMENTAL In this study were collected 13 samples from residential tap water selected randomly in the 13 different regions colleges of University of Babylon using the RAD H 2 O technique this device offers an accurate measurement faster reading it is portable and eliminates the need for noxious chemicals. The schematic diagram of this device is presented in Fig. 2 below. Using RAD H 2 O technique employs closed loop concept consisting of three components a the RAD7 or radon monitor on the left b the water

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I. H. Kadhim and K. H. Hatif: Estimated the Concentration of…. 2098 vial with aerator in the case near the front and c the tube of desiccant supported by the retort stand above as marked in the Fig. 6. Fig. 2: Schematic presentations of radon-in-air monitor RAD-7. Adapted from reference with permission 7 The RAD-H 2 0 method employs a closed loop aeration scheme whereby the air volume and water volume are constant and independent of the flow rate. The air re-circulates through the water and continuously extracts the radon until a state of equilibrium develops. The RAD-H 2 0 system reaches this state of equilibrium within about 5 min after which no more radon can be extracted from the water. The operation of this device is based on the following principle 1 radon is expelled from a water sample by using a bubbling kit 2 expelled radon enters a hemisphere chamber by air circulation 3 polonium decayed from radon is collected onto a silicon solid-state detector by an electric field and 4 radon concentration is estimated from the count rate of polonium 7 . On the RAD7 one among the two available protocols i.e. Wat-40 and Wat-250 will be selected depending on the size of vial 40 or 250 mL that is being used for water sampling here we used Wat-250 and sample size of 250 mL. This also decides the extraction efficiency or percentage of radon removed from the water to the air loop. For our used protocol of Wat-250 the extraction efficiency was usually very high typically 95 for a 250 mL sample vial 6 . The 250 mL sample bottle was connected to the RAD-7 and the internal air pump of the radon-monitor was used for re-circulating a closed air-loop through the water sample purging radon from the water into the air-loop. The air is re-circulated through the water continuously to extract the radon until RAD-H 2 O system reaches a state of equilibrium

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Int. J. Chem. Sci.: 144 2016 2099 within about 5 min after which no more radon can be extracted from the water. After reaching equilibrium between water air and radon progeny attached to the passivity implanted planar silicon detector the radon activity concentration measured in the air loop was used for calculating the initial radon-in-water concentration of the respective sample. The RAD-7 allows determination of radon-in-air activity concentrations by detecting the alpha decaying radon progeny 218 Po and 214 Po using passivity implanted planar silicon detector. The radon monitor RAD-7 uses a high electric field above a silicon semi- conductor detected at ground potential to attract the positively charged polonium daughters 218 Po and 214 Po which are counted as a measure of 222 Rn concentration in air 67 . The pump runs for 5 min aerating the sample and delivering the radon to the RAD7. The system will wait a further 5 min and then it starts counting. During the 5 min of aeration more than 95 of the available radon is removed from the water and the components automatically perform everything required to determine the radon concentration in the water. After 5 min it prints out a short-form report 68 . The same thing is repeated again for 5 min later and for two more 5-min periods after that. Thus radon gas is collected through the energy specific windows which eliminate interference and maintain very low backgrounds and later counted for the radon concentration. 222 Rn activities are then expressed with uncertainty down to under ± 5. At the end of the run 30 min after the start the RAD7 prints out a summary showing the average radon readings from the four cycles counted a bar chart of the four readings and a cumulative spectrum 7 . The annual effective dose to an individual consumer due to intake of radon from drinking water is evaluated using the Eq. 1 9 as shown in the Table 1. E KCKMt …1 where E is the committed effective dose from ingestion Sv K is the ingesting dose conversion factor of 222 Rn 10 -8 Sv.Bq -1 9 C is the concentration of 222 Rn BqL -1 KM is the water consumption 2 L.day -1 t is the duration of consumption 365 days 10 . The radon concentration of drinking waters decreases during storage processing etc. so by the evaluation of dose the consumption test is that of water taken directly from the tap 9 . RESULTS AND DISCUSSION Table 1 shows the results obtained in this study where the : Mean represents the value of average concentration SD represents the value of the standard deviation High highest value Low is lower value of the average radon concentration and are all measured in Bq.L -1 W refers to Water.

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I. H. Kadhim and K. H. Hatif: Estimated the Concentration of…. 2100 Table 1: Radioactive Radon gas concentrations in samples from water university of Babylon Sample point Mean Bq.L -1 High Bq.L -1 Low Bq.L -1 Effective dose mSv.y -1 W1 0.29 ± 0.23 0.579 0 0.015 W2 0.325 ± 0.13 0.435 0.145 0.017 W3 0.108 ± 0.13 0.288 0 0.005 W4 0.254 ± 0.24 0.579 0 0.013 W5 0.217 ± 0.08 0.29 0.145 0.011 W6 0.144 ± 0.16 0.29 0 0.007 W7 0.072 ± 0.08 0.145 0 0.003 W8 0.144 ± 0.11 0.29 0 0.007 W9 0.108 ± 0.07 0.145 0 0.005 W10 0.108 ± 0.13 0.29 0 0.005 W11 0.217 ± 0.18 0.435 0 0.011 W12 0.108 ± 0.07 0.145 0 0.005 W13 0.289 ± 0.2 0.576 0.145 0.015 To ensure the quality control and reliability of the sampling and measurement methods each sample was analyzed in 4 cycles where we calculated the mean of these 4 readings and finally we calculated the mean for the 13 samples means. Table 1 show there is difference in measurement results for water according to locations samples as shown in Fig. 3 where the radon concentrations ranged from 0.325 to 0.072 Bq.L -1 with a mean of 0.18 Bq.L -1 . The main Study finding points that all the readings for wells and springs were lower than the maximum contaminated level MCL of 11.1 Bq.L -1 . 311 These generally low concentration levels of radon in water tap could be explained from the geological context of the surrounding rocks. Indeed and environmental conditions 12 . From the spectra that shown in Fig. 4 and 5 for lower and higher of location sample in study area can be noted the relation between the count rate and the energy which consist of Radon daughters in A 218 Po B 214 Po and Thoron daughters D 216 Po E 212 Po.

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Int. J. Chem. Sci.: 144 2016 2101 Radon concentration Bq/L Sample number 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 1 2 3 4 5 6 7 8 9 10 11 12 13 Fig. 3: Diagram showing variation in radon concentration of the water samples Count Energy MeV 700 600 500 400 300 200 100 2 3 4 5 6 7 8 9 Fig. 4: Alpha energy spectrum of location Sample W7 Count Energy MeV 700 600 500 400 300 200 100 2 3 4 5 6 7 8 9 Fig. 5: Alpha energy spectrum of location Sample W2

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I. H. Kadhim and K. H. Hatif: Estimated the Concentration of…. 2102 As there is no absolute safe value of radiation from radon on general public. Although there are few studies on radon level in the water in Iraq 1314 no water radon level reference has been established and therefore there has been no specific safe limit value for radon until now in Iraq. Even in the neighbor countries no standard safe level has been developed and they still depend on the U.S. or European standard safe levels. In comparison with radon concentration in some countries the studies described in the Table 2 we find that the average concentration of radon in water lower as compared with these studies: Table 2: Shows the average of radon concentration in the water for some countries compared to the present research Country Radon concentration average Ref. Iraq- Nenava 1.133 Bq.L -1 13 Iraq -River Hilla 0.181 Bq.L -1 14 Present study Iraq-Uni. of Bab. 0.183 Bq.L -1 Iraq- Najaf Range 0.188 – 0.027 Bq.L -1 15 Turkey 0.091 Bq.L -1 16 Kuwait 0.74 Bq.L -1 17 Syria 13 Bq.L -1 18 Iran 0.21-3.89 Bq.L -1 19 Jordon 3.9 Bq.L -1 20 Khartoum 59.2 Bq.L -1 21 CONCLUSION i Compared with the international references our findings showed that there was no increasing in the exposure of radon in the different drinking water sources in University of Babylon. Several factors might explain the findings: radon decay and radon aeration mixture of water from different sources before pumping and the travel distance and time. ii All results for samples were less than the allowed concentration level of 11.1 Bq.L-1 As defined by the Environmental Protection Agency EPA 3 and the effective dose 1.74 μSv.y1 was less than the UNSCEAR and WHO recommended limit for members of the public of 1 mSv.y-1. 1011

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Int. J. Chem. Sci.: 144 2016 2103 REFERENCES 1. H. Cember Introduction to Health Physics Pergamon Press Inc. 1969. 2. J. M. Reid The Atomic Nucleus Manchester University Press Second Edition 1986. 3. Environmental Protection Agency United States Environmental Protection Agency A Citizen’s Guide to Radon 2009. 4. Health Effects of Exposure to Radon Committee on Health Risks of Exposure to Radon BEIR VI National Research Council 1999. 5. Map data2014 Google www.google.iq/maps/place/University of Babylon. 6. Durridge Company Inc. RAD7 Radon Detector. User Manual 2015. 7. Durridge Company Inc. RAD7 RADH 2 O Radon in Water Accessory Owners Manual 2016. 8. R. K. Somashekar and P. Ravikumar Radon Concentration in Groundwater of Varahi and Markandeya River Basins Karnataka State India J. Radioanalytical and Nuclear Chem. 285 343-351 2010. 9. Somlai S. Tokonami T. Ishikawa P. Vancsura M. Gaspar V. Jobbagy J. Somlai and T. Kovacs 222 Rn Concentrations of Water in the Balaton Highland and in the Southern Part of Hungary and the Assessment of the Resulting Dose Radiat. Meas. 42 491- 495 2007. 10. World Health Organisation WHO Third Ed. Guidelines for Drinking Water Quality World Health Organization Geneva 1 2004. 11. UNSCEAR United Nations Scientific Committee on the Effects of Atomic Radiation. Ionizing Radiation: Sources and Effects of Ionizing Radiation New York USA 1993. 12. N. U. Khattak M. A. Khan M. T. Shah and M. W. Javed Radon Concentration in Drinking Water Sources of the Main Campus of the University of Peshawar and Surrounding Areas Khyber Pakhtunkhwa Pakistan J. Radioanalytical and Nuclear Chem. 290 493-505 2011. 13. Sabah Yousif Hassan Ukla Determination of Radon Uranium and Other Radioactive Isotopes Concentration In Different Types of Natural Water in Nenava Governorate M.Sc. University of Mosul Iraq 2004.

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I. H. Kadhim and K. H. Hatif: Estimated the Concentration of…. 2104 14. Khalid H. H. Al-Attiyah and Inaam H. Kadhim Measurement and Study of Radioactive Radon Gas Concentrations in the Selected Samples of River Hilla/Iraq J. Nat. Sci. Res. 314 117-123 2013. 15. Ali Abid AboJassim and Ahmed Rahim Shitake Estimated the Mean of Annual Effective Dose of Radon Gases for Drinking Water in Some Locations at Al-Najaf City J. Kufa – Phys. 52 52-58 2013. 16. C. Canbazo ğlu M. Do ğru N. çelebi and G. Kopuz Assessment of Natural Radioactivity in Elazıg Region Eastern Turkey J. Radioanalytical and Nuclear Chem. 292 375-380 2012. 17. A. F. Maged Estimating the Radon Concentration in Water and Indoor Air Environ Monit Assess 152 195-201 2009. 18. G. Jonsson Solid State Nuclear Track Detector in Radon Measurement Indoor and Soil Nucl. Tracks Radiat. Meas. 25 335-338 1991. 19. A. Behtash A. Jalili-Majareshin and D. Rezaei-Ochbelagh Radon Concentration in Hot Springs of the Touristic City of Sarein and Methods to Reduce Radon in Water Radiation Phys. Chem. 81 749-757 2012. 20. A. T. Al-Kazwini and M. A. Hasan Radon Concentration in Jordanian Drinking Water and Hot Springs Institute of Physics Publishing J. Radiol. Port. 23 439-448 2003. 21. A. K. Sam H. Idriss and I. Salih Study of Radon in Ground Water and Physicochemical Parameters in Khartoum State J. Radioanalytical and Nuclear Chem. 290 333-338 2011. Revised : 14.07.2016 Accepted : 17.07.2016