In the present work, radon concentration was measured for different types of bottled drinking water and carbonated drink samples that are available in Iraqi markets. Radon measurements were carried out using a RAD-7 electronic radon detector. Annual effective dose was also calculated. The measured radon concentration in samples of bottled drinking water ranged from 0.0354 to 0.248 Bq/l with a mean value of 0.11265 Bq/l and the measured radon concentration in the samples of the carbonated drinks lay between 0.0354 and 0.283 Bq/l with a mean value of 0.1418 Bq/l. The mean values of the effective dose in all samples of bottled drinking water and carbonated drinks were found to be 0.410844 and 1.022 μSv/y respectively. The results of this work revealed that the radon concentrations were lower than the recommended limits indicated by the World Health Organization and by the regulatory bodies of the European Union.

INTRODUCTION

Nuclear radiation naturally exists in the environment in which humans live. This means that human beings receive exposure from naturally occurring radiation in soil, water, air and food. In this context, radium-226 is the fifth decay product of uranium-238; it decays into radon-222, which is the heaviest gaseous element in the natural decay series of uranium, thorium and actinium (ICRP 1999). Radon gas is characterized by naturally emitting alpha particles. Radon is a chemically inert, colorless, tasteless and odorless gas which results from the natural radioactive decay of the uranium, radium and thorium that exist everywhere in traces in the rocks and soils of the earth's crust (Reid 1986; Gillmore & Jabarivasal 2010). Naturally, radon can be classified into three isotopes: first, 222Rn, which is produced from the decay of 238U with a natural abundance of about 99.3% of the total uranium within the earth's crust; second, thoron, 220Rn, which is produced in nature during the decay of 232Th; and finally 219Rn, which is formed during the decay of 235U (Gillmore & Jabarivasal 2010). The isotope 222Rn has a half-life of 3.8 days and is the most stable and abundant isotope of radon in nature. It decays by emitting an α-particle of (5.49 MeV) and creates radioactive daughters (Reid 1986; Gillmore & Jabarivasal 2010). The radon can be dissolved and transported into water by pores in rock and soil. The associated health hazard gives rise to a radiation dose which results from either inhalation or ingestion. In this sense, radon gas can be transmitted from water to the air, and when inhaled, this leads to the exposure of the lungs to radiation risk. From the other side, ingestion of water containing radon is considered to directly impact the stomach (Khursheed 2000). It should be noted that around 1–2% of radon in the air comes from drinking water (USEPA 1991). Therefore breathing radon increases the risk of lung cancer over the course of a lifetime. Furthermore, drinking water containing radon presents a risk of developing internal organ cancers, primarily stomach cancer (USEPA 1991). Some people believe that the dissolved minerals in the water could be good whereas others do not. There are some scientists who have recently used the RAD-7 detector to measure the concentration of radon in water (Abdalsattar & Abbas 2012; Ali 2013; Ali & Ahmed 2013; Guida et al. 2013, 2015; Ali et al. 2015a, 2015b). For this purpose, it is fundamental to have regulations regarding the natural radioactivity in bottled water and carbonated drinks. The aim of this study was to measure the radon concentrations in different types of bottled water and carbonated drinks that are commonly used in Iraq. Additionally, this study included the calculation of annual effective dose in all samples.

MATERIAL AND METHODS

Collection of samples

Thirty-three samples (i.e. 15 bottled water and 18 carbonated drinks) were collected from Iraqi markets. These samples were divided into two groups according to the trademark and the country of manufacturing as shown in Tables 1 and 2.

Table 1

Bottled water samples used in the current study

No.Sample codeTrade name of sampleProducing country
B1 Nawar Iraq (Najaf) 
B2 Sanan 
B3 Al-tour 
B4 Mazaya 
B5 Bratha 
B6 Al-saqi 
B7 Sawa Iraq (Babylon) 
B8 Alwaha 
B9 Aljanen Iraq (Baghdad) 
10 B10 Venazya 
11 B11 Mina Iraq (Kirkuk) 
12 B12 Karwan 
13 B13 Life Iraq (Zakho) 
14 B14 Zalal Iraq (Duhok) 
15 B15 Alrawdhatan Kuwait 
No.Sample codeTrade name of sampleProducing country
B1 Nawar Iraq (Najaf) 
B2 Sanan 
B3 Al-tour 
B4 Mazaya 
B5 Bratha 
B6 Al-saqi 
B7 Sawa Iraq (Babylon) 
B8 Alwaha 
B9 Aljanen Iraq (Baghdad) 
10 B10 Venazya 
11 B11 Mina Iraq (Kirkuk) 
12 B12 Karwan 
13 B13 Life Iraq (Zakho) 
14 B14 Zalal Iraq (Duhok) 
15 B15 Alrawdhatan Kuwait 
Table 2

Carbonated drink samples used in the current study

No.Sample codeTrade name of sampleProducing country
C1 Shani Iraq (Kufa) 
C2 7 Up 
C3 Frei 
C4 Diet Pepsi 
C5 Miranda apple 
C6 Miranda 
C7 7 Up Iraq (Babylon) 
C8 Akad oranges 
C9 Pepsi Cola 
10 C10 Pepsi 
11 C11 Sprite 
12 C12 Crystal Up Iraq (Karbala) 
13 C13 Crystal Pepsi 
14 C14 Shani Iraq (Kirkuk) 
15 C15 Diet Kazhoz Iraq (Arbel) 
16 C16 Sprite Turkey 
17 C17 Frida Saudi Arabia 
18 C18 Fimto Saudi Arabia 
No.Sample codeTrade name of sampleProducing country
C1 Shani Iraq (Kufa) 
C2 7 Up 
C3 Frei 
C4 Diet Pepsi 
C5 Miranda apple 
C6 Miranda 
C7 7 Up Iraq (Babylon) 
C8 Akad oranges 
C9 Pepsi Cola 
10 C10 Pepsi 
11 C11 Sprite 
12 C12 Crystal Up Iraq (Karbala) 
13 C13 Crystal Pepsi 
14 C14 Shani Iraq (Kirkuk) 
15 C15 Diet Kazhoz Iraq (Arbel) 
16 C16 Sprite Turkey 
17 C17 Frida Saudi Arabia 
18 C18 Fimto Saudi Arabia 

Laboratory procedure

The RAD-7 can be defined as a true, real-time, continuous monitoring device for radon. This means that variability in the radon concentration levels can be observed during the period of measurement. This is very useful, in the sense that one can investigate the factors influencing the radon concentration over time. These factors include changes in temperature, wind speeds, and relative humidity and may also give an insight into air movements inside a room (Durridge 2012).

Radon concentrations in the study samples were measured using a RAD-7 electric radon detector that connected to the RAD-H2O accessory for a period of 1 month. Figure 1 shows a schematic diagram of the RAD-H2O setup. The RAD-7 was used for measuring radon in water by connecting it to a bubbling kit that enabled gas to be released from the sample of water into the air existing in a closed loop. The water sample was taken into a radon-tight reagent bottle of 250 ml capacity connected to a glass bulb containing calcium to absorb the moisture and to the closed circuit of a zinc-sulphide-coated detection chamber. This chamber acted as a scintillator to detect alpha particles. The air was then circulated in a closed circuit for a period of 5–10 min until the radon was uniformly mixed with the air where the resulting alpha particles were then recorded. It should be noted that the high humidity reduced the efficiency of collection of the polonium-218 atoms that formed when radon decayed inside the chamber. However, the 3.05 min 218Po half-life indicates that almost all the decays were actually counted at the first 20 min of measurement. So, an increase in humidity above 10% across the last 10 min of the counting period would not have a considerable effect on the accuracy of the measurement. Nevertheless, if the humidity increased above 10% before the end of the first counting cycle, then there would be an error whose level is hard to define (RAD-7, RAD-H2O). This therefore gives a direct measure for the radon concentration.
Figure 1

Schematic representation of the RAD-7 instrument (Durridge 2012) for measuring radon in water.

Figure 1

Schematic representation of the RAD-7 instrument (Durridge 2012) for measuring radon in water.

The annual effective dose

The annual effective dose for an individual consumer due to the radon intake from bottled water was evaluated using the following equation (Alam et al. 1999): 
formula
1
Dw is the annual effective dose (Sv/y) due to ingestion of radionuclides from the consumption of water; Cw is the concentration of 222Rn in the ingested drinking water (Bq/l); CRw is the annual intake of drinking water (l/y) and Dcw is the ingested dose conversion factor for 222Rn (Sv Bq–1). For the purpose of effective dose calculation, a dose conversion factor of 5 × 10–9 Sv/Bq was used (UNSCEAR 1999). The annual effective dose due to intake of 222Rn from drinking water is calculated considering that an adult (age 18 years), on average, takes 730 l water annually (Cevik et al. 2006). Following ingestion of 222Rn dissolved in drinking water, mean effective doses per litre (nSv/l) and annual effective doses (mSv/y) were calculated (UNSCEAR 2000). In addition to this, the annual effective dose can be calculated from the carbonated drink samples using Equation (1); however, the annual intake of carbonated drinks (l/y) is different, and is equal to about (66 l/y) (Abdalsattar & Abbas 2012).

RESULTS AND DISCUSSION

The results for the radon concentration and the average of the annual effective dose in different types of bottled water and carbonated drink samples are shown in Tables 3 and 4. The results for radon concentration in samples of bottled drinking water varied from 0.0354 ± 0.005 Bq/l in sample code B9 (Alganaean) to 0.248 ± 0.015 Bq/l in sample code B13 (Life) with an average value of 0.11265 Bq/l. However, in sample code B14 (i.e. Zalal) no measurement was found, as shown in Table 3. All samples in Table 4 had radon concentrations except samples C5, C6, C14 and C16, which were not detected by the detector; therefore we excluded them from the results. The radon concentration varied from 0.0354 ± 0.005 Bq/l in sample code C12 (Crystal Up) to 0.283 ± 0.016 Bq/l in sample code C15 (Diet Kazhoz) with an average value of 0.1418 Bq/l.

Table 3

The concentrations of radioactive radon gas rate and the annual effective dose in samples of bottled drinking water used in the current study

Radon concentration (Bq/m3)
Radon concentration (Bq/l)
The annual effective dose rate (mSv/y)
No.Sample codeMean± ErrorsMean± ErrorsMean± Errors
B1 70.9 8.42 0.0709 0.008 0.25 0.0009 
B2 94.6 9.72 0.0946 0.009 0.34 0.0012 
B3 212.5 14.57 0.2125 0.014 0.77 0.0028 
B4 106.5 10.31 0.1065 0.010 0.38 0.0013 
B5 177.25 13.31 0.1772 0.013 0.64 0.0023 
B6 141.5 11.89 0.1415 0.011 0.51 0.0018 
B7 71 8.42 0.071 0.008 0.26 0.0009 
B8 95 9.74 0.095 0.009 0.34 0.0012 
B9 35.4 5.94 0.0354 0.005 0.12 0.0004 
10 B10 132.75 11.52 0.1327 0.011 0.48 0.0017 
11 B11 96 9.79 0.096 0.009 0.35 0.0012 
12 B12 89 9.43 0.089 0.009 0.32 0.0011 
13 B13 248 15.75 0.248 0.015 0.91 0.0033 
14 B14 BLDa – BLDa – BLDa – 
15 B15 118 10.86 0.118 0.010 0.43 0.0015 
Mean 112.65 0.11265 0.410844 
Radon concentration (Bq/m3)
Radon concentration (Bq/l)
The annual effective dose rate (mSv/y)
No.Sample codeMean± ErrorsMean± ErrorsMean± Errors
B1 70.9 8.42 0.0709 0.008 0.25 0.0009 
B2 94.6 9.72 0.0946 0.009 0.34 0.0012 
B3 212.5 14.57 0.2125 0.014 0.77 0.0028 
B4 106.5 10.31 0.1065 0.010 0.38 0.0013 
B5 177.25 13.31 0.1772 0.013 0.64 0.0023 
B6 141.5 11.89 0.1415 0.011 0.51 0.0018 
B7 71 8.42 0.071 0.008 0.26 0.0009 
B8 95 9.74 0.095 0.009 0.34 0.0012 
B9 35.4 5.94 0.0354 0.005 0.12 0.0004 
10 B10 132.75 11.52 0.1327 0.011 0.48 0.0017 
11 B11 96 9.79 0.096 0.009 0.35 0.0012 
12 B12 89 9.43 0.089 0.009 0.32 0.0011 
13 B13 248 15.75 0.248 0.015 0.91 0.0033 
14 B14 BLDa – BLDa – BLDa – 
15 B15 118 10.86 0.118 0.010 0.43 0.0015 
Mean 112.65 0.11265 0.410844 

aBLD: This refers to the detected value being less than the detection limit of the device used, which is 4 Bq/m3.

Table 4

The concentrations of radioactive radon gas rate and the annual effective dose in samples of carbonated drinks used in the current study

Radon concentration (Bq/m3)
Radon concentration (Bq/l)
The annual effective dose rate (mSv/y)
No.Sample codeMean± ErrorsMean± ErrorsMean± Errors
C1 212.5 14.57 0.2125 0.014 0.07 0.0048 
C2 176.9 13.30 0.1769 0.013 0.058 0.0043 
C3 82 9.05 0.082 0.009 0.027 0.0029 
C4 88.7 9.41 0.0887 0.009 0.029 0.0031 
C5 BLDa – BLDa – BLDa – 
C6 BLDa – BLDa – BLDa – 
C7 190 13.78 0.19 0.013 0.063 0.0045 
C8 177.2 13.31 0.177 0.013 0.059 0.0043 
C9 122 11.04 0.122 0.011 0.04 0.0036 
10 C10 106.4 10.31 0.106 0.010 0.035 0.0034 
11 C11 135 11.61 0.135 0.011 0.044 0.0038 
12 C12 35.4 5.94 0.035 0.005 0.011 0.0019 
13 C13 94.66 9.72 0.094 0.009 0.031 0.0032 
14 C14 BLDa – BLDa – BLDa – 
15 C15 283 16.82 0.283 0.016 0.093 0.0055 
16 C16 BLDa BLDa BLDa BLDa BLDa – 
17 C17 142 11.91 0.142 0.011 0.047 0.0039 
18 C18 140 11.83 0.14 0.011 0.046 0.0039 
Mean 141.98 0.1418 0.036 
Radon concentration (Bq/m3)
Radon concentration (Bq/l)
The annual effective dose rate (mSv/y)
No.Sample codeMean± ErrorsMean± ErrorsMean± Errors
C1 212.5 14.57 0.2125 0.014 0.07 0.0048 
C2 176.9 13.30 0.1769 0.013 0.058 0.0043 
C3 82 9.05 0.082 0.009 0.027 0.0029 
C4 88.7 9.41 0.0887 0.009 0.029 0.0031 
C5 BLDa – BLDa – BLDa – 
C6 BLDa – BLDa – BLDa – 
C7 190 13.78 0.19 0.013 0.063 0.0045 
C8 177.2 13.31 0.177 0.013 0.059 0.0043 
C9 122 11.04 0.122 0.011 0.04 0.0036 
10 C10 106.4 10.31 0.106 0.010 0.035 0.0034 
11 C11 135 11.61 0.135 0.011 0.044 0.0038 
12 C12 35.4 5.94 0.035 0.005 0.011 0.0019 
13 C13 94.66 9.72 0.094 0.009 0.031 0.0032 
14 C14 BLDa – BLDa – BLDa – 
15 C15 283 16.82 0.283 0.016 0.093 0.0055 
16 C16 BLDa BLDa BLDa BLDa BLDa – 
17 C17 142 11.91 0.142 0.011 0.047 0.0039 
18 C18 140 11.83 0.14 0.011 0.046 0.0039 
Mean 141.98 0.1418 0.036 

aBLD: This refers to the detected value being less than the detection limit of the device used, which is 4 Bq/m3.

The values of radon concentrations in bottled water and carbonated drink samples under study are lower than the maximum allowed concentration, which is 0.5 Bq/l (500 Bq/m3) as set by the WHO Guidelines for drinking water quality (WHO 2008) (Figures 2 and 3). The effective annual dose was calculated using Equation (1), and can be seen in Tables 3 and 4; for those people who are drinking bottled water and carbonated drinks annually the effective doses ranged from 0.12 mSv/y to 0.91 mSv/y and from 0.011 mSv/y to 0.093 mSv/y respectively. We found that all results of the effective annual dose for radon concentrations in the studied samples were lower than the reported normal limits for the world (i.e. 1 mSv/y) (UNSCEAR 2000).
Figure 2

This figure compares the mean of radon concentrations in bottled water with WHO published values.

Figure 2

This figure compares the mean of radon concentrations in bottled water with WHO published values.

Figure 3

This figure compares the mean of radon concentrations in carbonated drinks with WHO published values.

Figure 3

This figure compares the mean of radon concentrations in carbonated drinks with WHO published values.

By way of comparison, the results of this study with relevant studies conducted in Iraq are tabulated in Table 5. From this table it can be seen that the average concentrations of radon in the present study are lower in comparison with these studies.

Table 5

The mean of radon concentration in the water for some countries compared with the present research

No.Government and yearSample typeRadon concentrations (Bq/l)References
Karbala, 2012 Carbonated drinks 0.17–0.56 Abdalsattar & Abbas (2012)  
Najaf, 2013 Drinking water 0.0243–0.2255 Ali et al. (2015a, 2015b)  
Babylon, 2014 Drinking water 0.29 Wasan (2014)  
Karbala, 2015 Bottled mineral water 2.594 Abdalsattar & Rajaa (2015)  
Baghdad, 2015 Drinking water 0.012–0.283 Ali et al. (2015a, 2015b)  
Present study Bottled water 0.0354–0.248 – 
Present study Carbonated drinks 0.0354–0.283 – 
No.Government and yearSample typeRadon concentrations (Bq/l)References
Karbala, 2012 Carbonated drinks 0.17–0.56 Abdalsattar & Abbas (2012)  
Najaf, 2013 Drinking water 0.0243–0.2255 Ali et al. (2015a, 2015b)  
Babylon, 2014 Drinking water 0.29 Wasan (2014)  
Karbala, 2015 Bottled mineral water 2.594 Abdalsattar & Rajaa (2015)  
Baghdad, 2015 Drinking water 0.012–0.283 Ali et al. (2015a, 2015b)  
Present study Bottled water 0.0354–0.248 – 
Present study Carbonated drinks 0.0354–0.283 – 

CONCLUSION

According to the resulting data from this study, we can conclude that all radon concentrations and the annual effective dose which were obtained from different types of bottled drinking water and carbonated drinks are less than that allowed as the maximum concentration level according to the World Health Organization and EU Council (i.e. indicative dose, 1.0 mSv per annum; parametric value, 100 Bq/l). Finally, it may be argued that there is no significant radiological risk to inhabitants resulting from radon ingestion by way of the bottled drinking water and carbonated drinks available in Iraqi markets.

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