نوع مقاله : مقاله پژوهشی
نویسندگان
دانشگاه اراک، دانشکده علوم پایه، گروه فیزیک، اراک
چکیده
در این پژوهش، فعالیت ویژۀ عناصر پرتوزای طبیعی و مصنوعی برای 50 نمونۀ رسوبی جمع آوری شده از سرتاسر تالاب میانکاله در شمال ایران در ضلع جنوب شرقی دریای خزر با استفاده از آشکارساز فوق خالص ژرمانیومی اندازه گیری شد. همچنین کمیتهای پرتوشناختی و شاخصهای خطر ناشی از تابشهای گامای محیطی ناشی از این ویژه هستهها محاسبه و نقشۀ توزیع فعالیت معادل رادیوم و دز جذبی برای سرتاسر تالاب میانکاله با استفاده از نرم افزار GIS ترسیم شد. میانگین فعالیت ویژۀ Ra226 ، Th232، K40 و Cs137 به ترتیب8/17±312/37، 1/46±21/19، 1/65±16/06 و 270±4/81 بکرل بر کیلوگرم به دست آمد که برای ویژه هسته های پرتوزای طبیعی کمتر از مقدار میانگین جهانی است. بالاترین غلظت برای Ra226 مربوط به رسوبات مصب رود گلوگاه است. نتایج نشان دهندۀ رسوبگذاری سریع Th232 بلافاصله پس از ورود به تالاب است. بیشترین غلظت K40 و Cs137 به ترتیب در ناحیۀ دهانۀ رود گز و بخش آرام در ناحیۀ مرکزی تالاب مشاهده شد. میانگین فعالیت معادل رادیوم و دز جذبی به ترتیب 4/37±70/42 بکرل بر کیلوگرم و 1/94±32/73 نانوگری بر ساعت محاسبه شد که کمتر از مقدار میانگین جهانی است. نقشۀ توزیع فعالیت معادل رادیوم و دز جذبی میزان بالای این دو کمیت در رسوبات نواحی جنوبی و شرقی تالاب را نشان میدهد که دلیل آن ورود ویژه هستههای پرتوزا توسط جریان آب رودهای حوزۀ این تالاب است. به طور کلی میزان پرتوزایی کلی بر حسب معادل رادیوم در تالاب در نزدیکی دهانۀ رودخانه های با آبدهی بالاتر بیشتر است. مقدار میانگین برای کمیت های AEDEout، ELCR، AGDE، Iγ و Hex در تالاب میانکاله کمتر از مقدار مجاز آن است و به طور کلی نتایج این پژوهش نشان میدهد که میزان پرتوزایی ناشی از ویژه هسته های پرتوزای موجود در تالاب میانکاله، خطرات پرتوشناختی را برای سلامتی ساکنین این منطقه ایجاد نمی کند.
کلیدواژهها
موضوعات
عنوان مقاله [English]
Absorption dose distribution pattern and radiological risk assessment in sediments of Miankaleh international wetland, north of Iran
نویسندگان [English]
- Reza Pourimani
- Seyyedmohsen Mortazavishahroudi
- Roushanak Ghorbani
Department of Physics, Faculty of Science, Arak University, Arak, Iran
چکیده [English]
In this study, the specific activity of natural and artificial radioactive elements was measured for 50 sediment samples collected from throughout Miankaleh wetland in northern Iran on the southeastern side of the Caspian Sea using a High-Purity Germanium detector. Also, radiological parameters and hazard indicators due to environmental gamma radiation caused by these nuclei were calculated and a distribution map of Radium equivalent activity and absorbed Dose for the whole Miankaleh wetland was drawn using GIS software. The mean specific activity of 226Ra, 232Th, 40K and 137Cs respectively were 16.06±1.65, 21.19±1.46, 312.37±8.17 and 4.81±0.27 Bqkg-1 that for natural radioactive nuclei are less than the global average. The highest concentration of 226Ra is related to the sediments of the estuary of the Galougah River. The results show rapid deposition of 232Th immediately after entering the lagoon. The highest concentrations of 40K and 137Cs were observed in the mouth of the Gaz River and the calm part in the central area of the wetland, respectively. The mean values of Raeq and D respectively were 70.42±4.37 Bqkg-1 and 32.73 nGyh-1, which are less than the global average. The distribution map of Raeq and D shows the high amount of these two parameters in the sediments of the southern and eastern parts of the wetland, which is due to the entry of radionuclei by the water flow of rivers of this wetland basin. In general, the amount of radioactivity expressed in terms of radium equivalent in the wetland is higher near the mouth of rivers with higher water flow. The average value for AEDEout, ELCR, AGDE, Iγ and Hex in this wetland is less than the allowable value and, in general, the results of this study show that the amount of radiation due to the radionuclei in Miankaleh wetland does not pose radiological hazards to the health of the inhabitants of this area.
کلیدواژهها [English]
- Miankaleh international wetland
- environmental radiation
- dose distribution pattern
- radiological map
- United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), 2008, “Sources, effects and risks of ionizing radiation", New York: Report to the General Assembly with annexes.
- International Commission on Radiological Protection (ICRP), 2012. Compendium of dose coefficient based on ICRP Publication 119, 41(1).
- Y F Ali, et al., Front. Phys. 8 (2020) 234.
- M E Wrenn, et al., Phys. 48 (1985) 601.
- K Sankaranarayanan, Res. 429 (1999) 45.
- K M Miller, J L Kuiper, and I K Helfer, Environ. Radioact. 12, 1 (1990) 23.
- M J Frissel, and R Pennders, “Models for the accumulation and migration of 90Sr, 137 Cs, 239,240Pu and 241Am in the upper layer of soils”, Blackwell, Oxford (1983).
- Q He, and D E Walling, Radiat. Isot., 48 (1997) 667.
- J C Ritchie, and J R Mchenry, Environ. Qual. 19 (1990) 215.
- W Davidson, P Spezanno, and J Hilton, Environ. Radioact., 19 (1993) 109.
- United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), 1993, “Sources and effects of ionizing radiation”, New York: Report to the General Assembly with annexes.
- M A K AbdelHalim and A El-Taher, Radioanal. Nucl. Chem. 299 (2014) 1949.
- G Suresh, et al., Environ. Radioact., 102 (2011) 370.
- Geographic information system version 10.3 (GIS10.3) [Computer software], 2014, Retrieved from: https://www.esri.com
- S H Habibi, Dissertation, Islamic Azad University of Tehran-North (2001) (In persian).
- M Gharibreza, et al., Catena., 166 (2018) 339.
- A M MofidiKhajeh, et al. “Soil Conservation and Watershed Management Research Institute”, Tehran (2008).
- Civil Research Consulting Engineers (CRCE), 2008, “Identification studies of water resources of Miankaleh Peninsula., Mazandaran Regional Water Company” (In persian).
- L Parsaie, and A M MofidiKhajeh, “Paper presented at the Fifth National Conference on Watershed Management Science and Engineering of Iran” (2009) (In Persian).
- T Sufi, et al., “Iran Fisheries Science Research Institute” (2006) (In Persian).
- International Atomic Energy Agency (IAEA), 2003, “Collection and Preparation of bottom sediment sample for analysis of radionuclides and trace element”, (IAEA-TECDOC-1360, Vienna).
- R Pourimani, and S M Mortazavi Shahroodi, J. Med. Phys. 15, 2 (2018) 126.
- J D S Paiva, E E Farias, and E J D Franca, Assessment of the equilibrium of Th-228 and Ra-228 by gamma-ray spectrometry in mangrove soils, 2018 https://inis.iaea.org/search/search.aspx?orig_q=RN:47013750.
- A Shahrokhi and T Kovacs, Sci. Eur. 33 (2021) 66.
- R Pourimani and F Anoosheh, J. Med. Phys. 12, 3 (2015) 189.
- R Pourimani and M Mohebian, J. Sci. Technol. Trans. A Sci. 45 (2021) 733.
- R Pourimani and S Rahimi, J. Med. Phys. 13, 4 (2016) 269.
- Organization for Economic Cooperation and Development (OECD), 1979, “Exposure to radiation from the natural radioactivity in building materials”, Report by a Group of Experts, Nuclear Energy Agency (Paris, France).
- European Commission (EC), 1999, Radiological protection principles concerning the natural radioactivity of building material, In EC radiation protection, 112, Directorate General Environment, Nuclear Safety and Civil Protection.
- International Commission on Radiological Protection (ICRP), 1990, Recommendations of the ICRP Publication 60, (Oxford: Pergamum Publication).
- J Beretka and P J Mathew, Health Phys. 48, 1 (1985) 87.
- R Pourimani and F Asadpour, Arak. Uni. Med. Sci. 19, 107 (2016) 9.
- R Pourimani and S M Mortazavi Shahroodi, “Paper presented at the Third National Conference on Biotechnology Innovation and Technology, Iranian Chemistry”, Tehran (2021).
- J S Chae, et al., Radioanal. Nucl. Chem. 319 (2019) 783.
- R Pourimani, R Fardad, and M Mirzaei, Environ. Sci. Technol. 23 (2021) 47.
- United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), 2000, “Sources and effects of ionizing radiation”, New York: Report to the General Assembly with annexes.
- H A Al-Trabuls, A E Khater, and F I Habbani, Phys. Chem. 80 (2011) 343.
- N M Fahmi, et al., “Paper presented at the Tenth Radiation Physics and Protection Conference”, Nasr City–Cairo, Egypt, November (2010) .
- A Shahrokhi, et al., Marine Pollution Bulletin, 163 (2021) 112009. https://doi.org/10.1016/j.marpolbul.2021.112009
- M R Abdi, M Kamali, and S Vaezifar, Pollut. Bull. 56, 4 (2008) 751.
- M R Abdi, et al., Pollut. Bull. 58, 5 (2009) 658.