The uranium (238U) decay series provides the most important isotopes of elements radium (226Ra), radon (222Rn), and polonium (210Po) with half-lives of about 1600 years, 3.8 days, and 140 days, respectively.
Although the chemical structure of radium is very similar to calcium, the fact that it produces a radioactive gas (radon) complicates its handling in the laboratory and natural environment. In this study, we used the average concentrations of naturally occurring radionuclide 226Ra in drinking water at different parts of Iran to estimate the annual effective dose. In the other part of the study, we measured the concentrations of 210Po in Iranian cigarettes to estimate the internal intake of this radionuclide and its concentration in the
lung tissues of smokers. The results indicate that the average concentration of 226Ra in Iranian drinking water was below the 100 mBq L-1 recommended by the World Health Organization while the average concentration of 210Po and 210Pb in Iranian cigarettes was relatively high in comparison with other cigarettes found on the market.Uranijev (238U) radioaktivni niz obuhvaća najvažnije izotope radija (226Ra), radona (222Rn) i polonija (210Po), a poluvijek raspada im je 1600 godina za prvi element, 3,8 dana za drugi te 140 dana za treći. Premda je radijeva kemijska struktura vrlo slična kalcijevoj, rukovanje njime u laboratoriju i prirodnome okolišu otežano je činjenicom da proizvodi radioaktivni plin radon.
S pomoću prosječnih koncentracija prirodnoga radionuklida 226Ra u pitkoj vodi izračunali smo njegovu godišnju efektivnu dozu u različitim dijelovima Irana. U drugome smo istraživanju izmjerili koncentracije 210Po u iranskim cigaretama i izračunali njegov unos i koncentracije u plućnome tkivu. Naši rezultati upućuju na to da je prosječna koncentracija 226Ra u pitkoj vodi niža od 100 mBq L-1 koju preporučuje Svjetska zdravstvena organizacija, dok je prosječna koncentracija 210Po i 210Pb u iranskim cigaretama relativno visoka u odnosu na druge cigarete dostupne na tržištu

A. Khater

A. Peres

B. Skwarzec

C. Colangelo

C. Ziegelheim

J. Emsley

J. Shapiro

P. Kotrappa

Saeed Mohammadi

Y. Parfenov

Elements of Natural Radioactive Decay Series in Iranian Drinking Water and CigarettesThe uranium (238U) decay series provides the most important isotopes of elements radium (226Ra), radon (222Rn), and polonium (210Po) with half-lives of about 1600 years, 3.8 days, and 140 days, respectively. Although the chemical structure of radium is very similar to calcium, the fact that it produces a radioactive gas (radon) complicates its handling in the laboratory and natural environment. In this study, we used the average concentrations of naturally occurring radionuclide 226Ra in drinking water at different parts of Iran to estimate the annual effective dose. In the other part of the study, we measured the concentrations of 210Po in Iranian cigarettes to estimate the internal intake of this radionuclide and its concentration in the lung tissues of smokers. The results indicate that the average concentration of 226Ra in Iranian drinking water was below the 100 mBq L-1 recommended by the World Health Organization while the average concentration of 210Po and 210Pb in Iranian cigarettes was relatively high in comparison with other cigarettes found on the market.</jats:p

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Archives of Industrial Hygiene and Toxicology

Elements of Natural Radioactive Decay Series in Iranian Drinking Water and Cigarettes

Uranijev (238U) radioaktivni niz obuhvaća najvažnije izotope radija (226Ra), radona (222Rn) i polonija (210Po), a poluvijek raspada im je 1600 godina za prvi element, 3,8 dana za drugi te 140 dana za treći. Premda je radijeva kemijska struktura vrlo slična kalcijevoj, rukovanje njime u laboratoriju i prirodnome okolišu otežano je činjenicom da proizvodi radioaktivni plin radon.

S pomoću prosječnih koncentracija prirodnoga radionuklida 226Ra u pitkoj vodi izračunali smo njegovu godišnju efektivnu dozu u različitim dijelovima Irana. U drugome smo istraživanju izmjerili koncentracije 210Po u iranskim cigaretama i izračunali njegov unos i koncentracije u plućnome tkivu. Naši rezultati upućuju na to da je prosječna koncentracija 226Ra u pitkoj vodi niža od 100 mBq L-1 koju preporučuje Svjetska zdravstvena organizacija, dok je prosječna koncentracija 210Po i 210Pb u iranskim cigaretama relativno visoka u odnosu na druge cigarete dostupne na tržištu.The uranium (238U) decay series provides the most important isotopes of elements radium (226Ra), radon (222Rn), and polonium (210Po) with half-lives of about 1600 years, 3.8 days, and 140 days, respectively.

Although the chemical structure of radium is very similar to calcium, the fact that it produces a radioactive gas (radon) complicates its handling in the laboratory and natural environment. In this study, we used the average concentrations of naturally occurring radionuclide 226Ra in drinking water at different parts of Iran to estimate the annual effective dose. In the other part of the study, we measured the concentrations of 210Po in Iranian cigarettes to estimate the internal intake of this radionuclide and its concentration in the

lung tissues of smokers. The results indicate that the average concentration of 226Ra in Iranian drinking water was below the 100 mBq L-1 recommended by the World Health Organization while the average concentration of 210Po and 210Pb in Iranian cigarettes was relatively high in comparison with other cigarettes found on the market

Mohammadi, Saeed

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235DOI: 10.2478/10004-1254-61-2010-1989ObservationELEMENTS OF NATURAL RADIOACTIVE DECAY SERIES IN IRANIAN DRINKING WATER AND CIGARETTESSaeed MOHAMMADIPayame Noor University, Physics Department, Mashad, IranReceived in July 2009Accepted in March 2010The uranium (238U) decay series provides the most important isotopes of elements radium (226Ra), radon (222Rn), and polonium (210Po) with half-lives of about 1600 years, 3.8 days, and 140 days, respectively. Although the chemical structure of radium is very similar to calcium, the fact that it produces a radioactive gas (radon) complicates its handling in the laboratory and natural environment. In this study, we used the average concentrations of naturally occurring radionuclide 226Ra in drinking water at different parts of Iran to estimate the annual effective dose. In the other part of the study, we measured the concentrations of 210Po in Iranian cigarettes to estimate the internal intake of this radionuclide and its concentration in the lung tissues of smokers. The results indicate that the average concentration of 226Ra in Iranian drinking water was below the 100 mBq L-1 recommended by the World Health Organization while the average concentration of 210Po and 210Pb in Iranian cigarettes was relatively high in comparison with other cigarettes found on the market.KEY WORDS: annual effective dose, polonium, radium, radon, uraniumMohammadi S. RADIOACTIVE DECAY ELEMENTS IN IRANIAN WATER AND CIGARETTESArh Hig Rada Toksikol 2010;61:235-239Uranium is a naturally occurring primordial radionuclide; it was one of the elements created right after the Big Bang (1). It is the last naturally occurring element in the periodic table. The decay products of uranium pass over 10 elements, all with very different chemical properties. These elements are transported by groundwater, and their composition in the solution varies with the surrounding rock/soil minerals. Different elements migrate at different rates due to their different chemistries, dissolving in some areas and precipitating in others (1). In the 238U decay series 8 alpha-particles are emitted from 238U to 206Pb. Alpha particles cause extensive ionisation in matter.The uranium decay series provide the most important isotopes of elements radium, radon, and polonium, which are all radioactive and alpha emitters. Although the chemistry of radium is relatively simple, the fact that it produces a radioactive gas (radon) complicates its handling in the laboratory and natural environment. The decay of radon produces radioactive atoms of At, Po, Bi, and Pb (1).The radioactive noble gas 222Rn is produced continuously from the decay of radium in the ground. It dissolves in groundwater, which often carries it in high concentrations and releases it to areas inhabited by humans. It diffuses readily through soil and into the atmosphere. Thus it is always present in the air and water at levels which are determined by local geology and meteorology. Its main target organ is the lung.The relatively high activity concentrations of 210Po in cigarettes increase the intake of this radionuclide and its concentration in the lung tissues adding to overall internal radiation dose among smokers (1).The aim of our study was to estimate the annual effective dose based on average concentrations of naturally occurring radionuclide 226Ra measured in 236drinking water in different parts of Iran. In the other part of research, we measured the concentrations of 210Po in Iranian cigarettes to estimate the internal intake of this radionuclide and its possible concentration in the lung tissues of Iranian smokers.MATERIALS AND METHODS226Ra determinationIn the winter and the summer between June 2003 and June 2004, we gathered samples of bottled drinking water (N=100) available in supermarkets from the northwest, northeast, west, central and south Iran (parts with highest population density) , and determined 226Ra activity in each. 226Ra activity was measured using the radon emanation method (2) with a minimum detection limit of 2 mBq L-1.Briefly, 226Ra in drinking water sample was concentrated and separated by co-precipitation on barium sulphate (Merck, Germany). The precipitate was dissolved in ethylenediaminetetraacetic acid (EDTA) (Merck, Germany), placed in a sealed bubbler and stored for ingrowths of 222Rn. After ingrowths, the gas was purged into a scintillation cell. After 4 hours, when the short-lived 222Rn daughters were in equilibrium with the parent, counted alpha-particle activity.The annual effective dose of 226Ra in drinking water was calculated according to the following formula:D = CRa x Ua x Dfwhere CRa is the concentration of 226Ra (Bq L-1), Ua is the annual adult intake of drinking water, which is about 40 L, and Df is a conversion factor of radioactivity to the absorbed dose (or dose equivalent per Bq) in μSv Bq-1. The United Nations Scientiﬁ c Committee on the Effects of Ionizing Radiation (UNSCEAR) recommended Df for the intake of 226Ra is 0.28 μSv Bq-1 (3).210Po and 210Pb determinationFor this experiment we used the method suggested by Saito (4). Several Iranian brands of cigarettes were selected from the market. We homogenised the content of three cigarette packs for each analysis and did it in triplicate. From each mixture, we allocated 15 g for 210Pb determination and another 15 g for 210Po determination.To each sample of 5 g of dry tobacco we added 1 mL of 208Po tracer (Merck, Germany). The sample was leached with 40 mL of concentrated nitric acid (Merck, Germany) heated at temperature not exceeding 70 °C in order to avoid losses of polonium by volatilisation. When the sample was close to the dryness, it was added another 30 mL of nitric acid. This procedure was repeated once more.Then we added 10 mL of hydrogen peroxide (Merck, Germany) to destroy organic matter and 10 mL of nitric acid (8 mol L-1) under heating. To a nearly dry sample, we added another 10 mL of nitric acid (8 mol L-1). The sample was filtered directly into a separation funnel containing 5 mL of tributylphosphate (TBP; Merck, Germany). The mixture was then shaken for ﬁ ve minutes. After 10 minutes at rest, the polonium was found in the aqueous phase. The extraction was repeated twice with 10 mL of nitric acid (8 mol L-1). Then the aqueous phase was nearly dried by heating in order to eliminate nitric acid. Then we added 20 mL of concentrated hydrochloric acid (Merck, Germany) under heating. When the sample was almost dry we added another 20 mL of hydrochloric acid (2 mol L-1).Iron was complexed by adding L-ascorbic acid (Merck, Germany) until the solution changed colour from yellow to colourless. The solution was then transferred to a plating cell, where 208Po and 210Po were spontaneously deposited onto a copper disc after 4 h of continuous agitation and heating at temperature below 70 °C. The disc was then washed with deionised water and left to dry at room temperature. The alpha spectrum was obtained by counting in a surface barrier detector.The counting efﬁ ciency was determined using an electrodeposited source of 241Am. The value obtained was 0.125±0.001. The yield of the process ranged from 23 % to 67 % and the typical lower limit of detection of this method was 5x10-5 mBq g-1 for 1,000 minutes of counting time.RESULTS AND DISCUSSIONNatural radioactivity from drinking waterAll waters in the biosphere have impurities. Successful monitoring, protection, and rational use of water from rivers and mountains requires complex and systematic studies of space-time distribution and migration of heavy elements such as 226Ra. Radium is a decay product of uranium and is generally in Mohammadi S. RADIOACTIVE DECAY ELEMENTS IN IRANIAN WATER AND CIGARETTESArh Hig Rada Toksikol 2010;61:235-239237radioactive equilibrium with it on a global basis. It is much more soluble in water than uranium and therefore more readily leached by groundwater, making its way to drinking water and food. At high concentrations, this route of exposure becomes very important (1).Table 1 shows 226Ra average activity concentrations in drinking water in different parts of Iran. They do not exceed the 1,000 mBq L-1 recommended by the World Health Organization (5) for drinking water. The concentration of 226Ra present in groundwaters used by people in the northwest and northeast Iran for medical purposes. Only in the southern part of Iran, 226Ra was relatively high in comparison to other parts.Table 1  Radioactivity of bottled water in different parts of Iran(N=100 samples)LocationAverage 226Ra concentration / mBq L-1North-West 2.1±0.1North-East 2.6±0.2Center 2.3±0.2West 2.1±0.1South 6.2±0.7Concentrations of 226Ra vary greatly from location to location (1). Radium in the body becomes incorporated in bone, where it remains virtually indeﬁ nitely. The protection standard for radium was originally based on a maximum level in the body (maximum body burden).Radium decays to 222Rn, which is an inert noble gas and the immediate daughter product of 226Ra. Natural radiation accounts for the majority of human exposure to radiation, and 222Rn and its short-lived daughter products are the largest contributors to this radiation dose. Because of the radon health concern, several methods have been developed to monitor for radon and its daughters in air (6).Natural radioactivity from cigarette smokeThe relatively high activity concentrations of 210Po that are usually found in cigarettes increase internal intakes of this radionuclide and its concentration in the lung tissues of smokers. Polonium is a reactive, silvery-gray metal that dissolves in dilute acids. It is fairly volatile and about half will evaporate within two days if kept at 55 °C. A gram capsule of Polonium will reach 500 °C because of the intense alpha-radiation (7). That might contribute signiﬁ cantly to an increase in the internal radiation dose among smokers.In addition to 210Po, 210Pb with a half-life of 22 years is found in cigarettes as well. Since the burning temperature of a cigarette is around 700 °C and 210Pb is supposed to volatilise at temperature over 500 °C, the percentage of 210Pb effectively inhaled will be an additional source of 210Po for the lungs. The annual effective doses were calculated on the basis of 210Po and 210Pb intake with the cigarette smoke.Virtually all soils contain radium, a radioactive element that decays into 210Pb and 210Po. In addition, phosphate ore used to make fertilisers used on tobacco ﬁ elds contains these isotopes in relatively high concentrations. While tobacco plants can absorb 210Pb and 210Po through their roots, relatively little enters this way (1). When 226Ra, as a component of soil and fertiliser, decays, it gives rise to 222Rn, a gas that escapes into the air. This radon decays into its daughters, which have high electric charges that make them attach to dust particles. These dust particles stick to the tips or heads of the hairs of Tobacco leaves. Almost all the radioactivity of tobacco comes from this air deposition process. During processing of tobacco to cigarettes, this radioactivity is not removed from the tobacco leaves (1).Equivalent doses resulting from a single disintegration of 210Po (alpha-particle decay) are a thousand times greater than in the case of 210Pb decay (beta-particle decay) (8). The concentrations of 210Po in cigarettes range between 3 Bq kg-1 and 37 Bq kg-1 and vary with cigarette brand, due to different varieties of tobacco and manufacturing procedures (9).Our results show that the average activity concentration of 210Po in Iranian cigarettes was 26 mBq per cigarette. Assuming that 50 % of 210Po and 210Pb activity contained in a cigarette is inhaled during smoking, the annual activity concentration of 210Po intake by smoking of one pack (20 cigarettes) per day during one year is 94.9 Bq [(26 mBq per cigarette) x (20 cigarettes per day) = 520 mBq per day x 50 % = 260 mBq per day x 365 days per year = 94900 mBq per year = 94.9 Bq per year].By applying the dose conversion factor for adults of 4.3 μSv Bq-1 for 210Po and 5.6 μSv Bq-1 for 210Pb (10), the average annual committed effective dose is 408 μSv (94.9 Bq x 4.3 μSv Bq-1) and 532 μSv (94.9  Bq x 5.6  μSv Bq-1) or approximately 0.4 mSv to 0.5 mSv due to cigarettes smoking for 210Po and 210Pb, respectively.Table 2 shows an activity comparison between Iranian cigarettes and those from other countries that are mostly found on the Iranian market and reported Mohammadi S. RADIOACTIVE DECAY ELEMENTS IN IRANIAN WATER AND CIGARETTESArh Hig Rada Toksikol 2010;61:235-239238in literature (11, 12). As it can be seen, the average concentration of 210Po in Iranian cigarette is relatively high in comparison to other cigarette brands.Table 2  The average activity concentrations of 210Po in Iranian and foreign cigarettes (9, 10).CountryAverage 210Po concentration /mBq per cigaretteIran 26France 23Brazil 19Russia 14Egypt 14Turkey 14Poland 13CONCLUSIONS226Ra in bottled drinking available in supermarkets of Iran mBq L mBq Lwere well below the threshold level of 100 mBq L-1 recommended by the WHO for drinking water. On the other hand, the average activity concentration of 210Po in tested Iranian cigarettes (26 mBq per cigarette), was relatively high in comparison with foreign cigarette brands found on the market, suggesting an increase in internal radiation dose and possible health risks for the exposed smokers from 210Po and 210Pb contained in cigarette tobacco.REFERENCES1. Shapiro J. Radiation Protection: A Guide for Scientists, Regulators, and Physicians. 4th ed. Cambridge (MA): Harvard University Press; 2002.2. Kotrappa P, Stieff LR. Application of NIST 222Rn emanation standards for calibrating 222Rn monitors. Radiat Prot Dosim 1994;55:211-8.3. United Nations Scientiﬁ c Committee on the Effects of Atomic Radiation (UNSCEAR). UNSCEAR Report 2000, Vol. 1 [displayed 29 March 2010]. Available at http://www.unscear.org/unscear/en/publications/2000_1.html.4. Saito RT. Determination of 210Po and 210Pb in sea samples and aerosols [Determinação de 210Po and 210Pb em amostras marinhas e aerossóis, in Portuguese]. [MA thesis]. Sao Paulo, Brazil: Institute of Energy and Nuclear Research; 1996.5. World Health Organization (WHO). Radiological aspects. In: Guidelines for drinking water quality. 3rd ed. 2004 [displayed 29 March 2010]. Available at http://www.who.int/water_sanitation_health/dwq/en/gdwq3_9.pdf.6. Ziegelheim CJ, Busigin A, Phillips CR. Development of a continuous monitor for 226Ra in water. Health Phys 1982;42:317-27.7. Emsley J. The Elements. 3rd ed. Oxford: Oxford University Press; 2000.8. Parfenov YD. Polonium-210 in the environment and in the human organism. At Energy Rev 1974;12:75-143.9. Skwarzec B, Struminska DI, Ulatowski J, Golebiowski M. Determination and distribution of 210Po in tobacco plants from Poland. J Radioanal Nucl Chem 2001;250:319-22.10. Khater AEM. Polonium-210 budget in cigarettes. J Environ Radioact 2004;71:33-41.11. Peres AC, Hiromoto G. Evaluation of 210Po and 210Pb in cigarette tobacco produced in Brazil. J Environ Radioact 2002;62:115-9.12. Colangelo CH, Huguet MR, Palacios MA, Oliveira AA. Levels of 210Po in some beverages and in tobacco. J Radioanal Nucl Chem 1992;166:195-202.Mohammadi S. RADIOACTIVE DECAY ELEMENTS IN IRANIAN WATER AND CIGARETTESArh Hig Rada Toksikol 2010;61:235-239239SažetakELEMENTI NASTALI RASPADOM IZ PRIRODNIH RADIOAKTIVNIH NIZOVA U PITKOJ VODI I CIGARETAMA U IRANUUranijev (238U) radioaktivni niz obuhvaća najvažnije izotope radija (226Ra), radona (222Rn) i polonija (210Po), a poluvijek raspada im je 1600 godina za prvi element, 3,8 dana za drugi te 140 dana za treći. Premda je radijeva kemijska struktura vrlo slična kalcijevoj, rukovanje njime u laboratoriju i prirodnome okolišu otežano je činjenicom da proizvodi radioaktivni plin radon.S pomoću prosječnih koncentracija prirodnoga radionuklida 226Ra u pitkoj vodi izračunali smo njegovu godišnju efektivnu dozu u različitim dijelovima Irana. U drugome smo istraživanju izmjerili koncentracije 210Po u iranskim cigaretama i izračunali njegov unos i koncentracije u plućnome tkivu. Naši rezultati upućuju na to da je prosječna koncentracija 226Ra u pitkoj vodi niža od 100 mBq L-1 koju preporučuje Svjetska zdravstvena organizacija, dok je prosječna koncentracija 210Po i 210Pb u iranskim cigaretama relativno visoka u odnosu na druge cigarete dostupne na tržištu.KLJUČNE RIJEČI: polonij, radon, radionuklidi, uranijCORRESPONDING AUTHOR:Saeed Mohammadi, PhDPayame Noor University, Physics DepartmentP.O. Box 91735-43371 Moallem Boulevard, Mashad, IranE-mail: mohammadi@pnu.ac.irMohammadi S. RADIOACTIVE DECAY ELEMENTS IN IRANIAN WATER AND CIGARETTESArh Hig Rada Toksikol 2010;61:235-239

Elements of Natural Radioactive Decay Series In Iranian Drinking Water and Cigarettes

Elementi nastali raspadom iz prirodnih radioaktivnih nizova u pitkoj vodi i cigaretama u Iranu

Elementi nastali raspadom iz prirodnih radioaktivnih nizova u pitkoj vodi i cigaretama u Iranu

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