Effective Dose of Radon 222 Bottled Water in Different Age Groups Humans: Bandar Abbas City, Iran

Radon 222 is a natural radioactive element with a half-life of 3.8 days. It is odorless and colorless as well as water-soluble. Consuming waters which contain high concentration of 222Rn would increase the effective dose received by different age groups. It would also be followed by an increased prevalence of cancer. In this research, 72 samples of the most commonly used bottled water in Bandar Abbas were collected in 3 consecutive months, May, June and July of 2013. Concentration 222Rn of was measured by radon-meter model RTM166-2. The effective dose received by the 4 age groups, male and female adults as well as children and infants was estimated using the equation proposed by UNSCEAR. The results revealed that the mean and range concentration of 222Rn in bottled waters were 641±9 Bq/m3 and 0-901 Bq/m3, respectively. The mean concentration of 222Rn in the well-known Marks followed this Zam Zam>Bishe>Koohrng>Dassani>Christal>Polour>Damavand>Sivan. Infants were observed to receive a higher effective dose than children. The highest and lowest effective dose received was found to belong to male adults and children, respectively.


Introduction
Radon 222 ( 222 Rn) is a natural radioactive element with a half-life of 3.8 days. It is colorless and odorless. By emission alpha particles during its decay, it can cause lung, blood and gastric cancer in the long run (Colmenero Sujo et al., 2004;Nagaraja et al., 2003;Smith, Zhang, & Field, 2007). Due to a high ionization power and in terms of internal radiation, an alpha particle is at the top list of hazards as compared to all other particles (Hamanaka, Shizuma, Wen, Iwatani, & Hasai, 1998). 222 Rn and its daughters, Po214 and Po218 are among the main and final products of the decay of Uranium 235 ( 235 U) chain, which can spread out of different sources such as surface and groundwater water, soil, igneous or sedimentary rocks (Kam & Bozkurt, 2007;Oner, Yalim, Akkurt, & Orbay, 2009). In the USA, 222 Rn is considered as the second cause of mortalities due to lung cancer, smoking being the first (Thompson, Nelson, Popkin, & Popkin, 2008). 222 Rn has a high water-solubility. A decrease in water temperature would lead to a rise of its solubility (Kam & Bozkurt, 2007). Due to the more contact of groundwater water with igneous and sedimentary rocks, concentration of radioactive contents in these waters can be higher than surface water sources (Akawwi, 2014;Ali, Khan, Akhter, Khan, & Waheed, 2010;Kam & Bozkurt, 2007;Rangela et al., 2002). Moreover, concentration 222 Rn in groundwater water sources is two to three times as high as other radioactive contents (Forte, Rusconi, Cazzaniga, & Sgorbati, 2006). People are constantly either externally or internally exposed to radioactive materials especially 222 Rn through respiration and drinking water (M.Rožmaric, Rogic, Benedik, & M.Štrok, 2012; United Nations Scientific Committee on the Effects of Atomic Radiation, 2000). A body of research has indicated that consuming waters which contain high concentrations of 222 Rn would raise the received effective dose and also the probability of affliction with lung and gastric cancer (Rožmarić, Rogić, Benedik, & Štrok, 2012). The standard set by World Health Organization (WHO) for the 222 Rn of drinking water is 100,000 Bq/m 3 (Risica & Grande, 2000). The same standard limit set by the United States Environmental Protection Agency (EPA) is 11,000 Bq/m 3 (K. Somlai et al., 2007). WHO and the European Committee have proposed the annually received effective dose of 222 Rn to be 0.1 mSv/y (K. Somlai et al., 2007). Consumption of bottled water has been on the rise in the last 30 years (Karamanis, Stamoulis, & Ioannides, 2007). Bottled waters are divided in two groups of mineral water and bottled water (Bharath et al., 2003). A great many research has indicated that the radioactive contents of bottled water especially mineral water are much more than that of the public distribution network (J. Somlai et al., 2002). According to world statistics, Iran ranks 14 th as for the consumption of mineral water (Kiliari & Pashalidis, 2008). Knowledge about the radioactive content of drinking water especially bottled water is minimal in Iran. In Bandar Abbas due to its hot and humid climate and less trust to the quality of tap water, people vastly rely on bottled drinking water. Therefore, the present research attempted to measure concentration of 222 Rn in 8 of the most famous Marks of bottled water in Bandar Abbas. Eventually, the effective dose received from drinking water was measured across male and female adults, children and infant age groups. These values were later compared with the standard limits.

Number of Samples and Measurement Concentration of 222 Rn
Samples were selected in three stages and within three months: May, June and July of 2013. Each month corresponded to one stage of data collection. In each stage, samples of the 8 most famous and widely-used bottled water Marks in Bandar Abbas city were randomly collected from stores: Dassani, Bishe, Polour, Zam-Zam, Damavand, Chrystal, Sivan and Koohrang. From each Marks, three 1.5-liter bottles were collected and kept at the temperature of 4 to 6°C in a chemistry lab of Bandar Abbas Water and wastewater Company (Binesh, Mohammadi, Mowlavi, & Parvaresh, 2010). On the whole in the three stages, 72 bottled water samples were selected as from among the most widely-used Marks of the city.

Figure 1. Location of Bandar Abbas city in Hormozgan province and Iran
Considering the effect of temperature on the radiation of 222 Rn, before the measurement the temperature of all samples was made uniform (12 °C) (Ishikawa, Tokonami, Yoshinaga, & Narazaki, 2005;K. Somlai et al., 2007). Concentration of 222 Rn was measured by Radon meter model RTM166-2 made by the sarad company ( Figure 2). www.ccsenet.org/gjhs Global Journal of Health Science Vol. 8, No. 2;2016 Sensitivity of this instrument in 150 minutes of constant measurement was 6.5 cts (min×KBq/m 3 ) (Ursulean, Coreţchi, Chiruţă, & Virlan, 2012). High sensitivity along with a spectral analysis of alpha can cut down on the response time even in low concentration. The measurement concentration of 222 Rn in the samples was done following the instructions provided by Sarad Company. Similarly, the 2 hour mean concentration of 222 Rn was recorded and analyzed for all the samples (GmbH, June 2007).

Estimating the Annually Effective Dose
Once an individual consumes a water containing 222 Rn, the alpha spread out during its decay can damage the DNA of the inner-gastric cells. On the other hand, by penetrating the gastric membrane, it can enter blood and can spread all throughout the body (Organization, 2004). Therefore, in order to estimate the annually received effective dose of 222 Rn through drinking bottled water, an equation is proposed by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) (J. Somlai et al., 2002): In this equation: E is the annually received effective dose (in mSv/y), K; the conversion coefficient concentration of 222 Rn to effective dose (Sv/Bq), G; the daily consumed water (l/d), C; the concentration of 222 Rn (Bq/l); T; the time span of water consumption (365 days) and 1000; the conversion coefficient of Sv to mSv.
K coefficient of male and female adults (17-65 years of age), children (4-14 years of age) and infants (younger than 2 years of age) is: 18×10 -9 Sv/Bq, 26×10 -9 Sv/Bq and 35×10 -9 Sv/Bq, respectively (Binesh et al., 2010; United Nations. Scientific Committee on the Effects of Atomic Radiation, 2009; K. Somlai et al., 2007). There is a limited world information about the daily amount of water consumed. A myriad of research has indicated that the amount of people's consumed water is less than 2 liters a day. It varies across different age groups. The daily amount of water consumption is a function of climate, physical activity, culture, economics etc. The daily amount of water consumed by male adults, female adults, children and infants was 2.723, 2.129, 0.431 and 0.327 l/p-d, respectively (Agency, October, 2004). The mean and range concentration of 222 Rn in all Marks were 641±9 and 0-901 Bq/m 3 , respectively. The range concentration of 222 Rn in bottled waters used in Bandar Abbas is much lower than other cities of Iran and other countries. As mentioned previously, this concentration of 222 Rn difference could be due to differing water source, temperature, and processing and storage time ( Table 2) (Ishikawa et al., 2005). Concentration 222 Rn of follows this order among the Marks: Zam-Zam>Bishe>Koohrang>Dassany>Crystal>Polour>Damavand>Sivan. Mean concentration of 222 Rn in all the Marks was observed to be lower than the standards set by WHO (100×10 -3 Bq/m 3 ) and EPA (11×10 -3 Bq/m 3 ) (Figure 3).

Conclusion
Mean concentration of 222 Rn in all bottled water Marks was found to be less than the standard limits set by WHO and EPA. The highest and lowest concentration belonged to Zam-Zam and Sivan Marks. The highest and lowest proportion of effective dose to the standard effective dose was found to belong to male adults (Zam-Zam) and children (Sivan). The highest and lowest effective dose received was found to belong to male adults and children, respectively (p value <0.05). Also Infants were observed to receive a higher effective dose than children. The annually received effective dose through the 222 Rn of bottled water in Bandar Abbas was lower than the standard limit (0.1 mSv/y) in all age groups.