Radon is readily soluble in water, and radon exposure caused by household water consumption may pose a threat to public health. In this study, the radon concentration in the tap water of residential buildings was measured, and the average value was 543.33 mBq L−1, which was in line with the radon concentration limit recommended by USEPA (11.11 Bq L−1) and EURATOM (100 Bq L−1), and also within the range of the results of radon concentration measurements in tap water in other countries or regions. Through water bath heating at different temperatures, the radon retention curves of multiple groups of samples at different temperatures were fitted and analyzed. The results showed that the radon retention continued to decrease between 25 and 70 °C, remained stable between 70 and 85 °C, and then continued to decline slowly. Combined with the measurement results, the effective doses of α- and β-particles emitted by 222Rn and its progenies to residents respiratory and alimentary tissues and organs were calculated using the computational model provided by ICRP under two typical water scenarios of shower and drinking water, and the results show that radon exposure caused by normal water consumption will not pose a serious threat to public health.

  • The radon concentration of domestic tap water in Urumqi, Xinjiang was measured.

  • The variation trend of radon concentration in tap water with temperature was analyzed.

  • The radiation dose contributed by radon exposure to residents under different water-use scenarios was calculated based on the actual water temperature.

  • The radiation doses to human organs from the α and β decay progenies of radon were calculated.

Radon, a colorless, odorless inert radioactive gas, has four radioactive isotopes (218Rn, 219Rn, 220Rn, and 222Rn) in nature. 222Rn has received extensive attention because its parent nucleus 226Ra is abundant in soil and rock and has the longest half-life (3.82 days) (ICRP 2007). The decay of 222Rn emits α-particles and produces a series of short-lived progenies such as 218Po, 214Pb, 214Bi, and 214Po (UNSCEAR 2000). Considering the soluble readily in water, 222Rn can easily diffuse from solid materials into the water and be transported when various types of water resources in nature come into contact with soil and rocks (Zhuo et al. 2001; Yasouka et al. 2008; Jantsikene et al. 2014; Mehra et al. 2016).

Water is an important factor affecting public health (WHO 2009). The major source of domestic water for urban residents is tap water supplied through the urban water supply network. 222Rn dissolved in tap water can be transported to residential buildings far away from water supply plants in a short period through the pipe network, and then degassed from water to indoor environment in the process of domestic water use, or be ingested by residents along with drinking water or food (UNSCEAR 2000; Vinson et al. 2008). The 222Rn and progenies which enter the respiratory system of the human body through respiration cannot be completely filtered, in breathing, the inhaled 222Rn is almost exhaled again, but the progenies of decay can attach to air particles and have a certain probability in the respiratory tract tissue surface adhesion and deposition (Vinson et al. 2008; Oner et al. 2009), α- or β-particles emitted by the decay of these short-lived progenies cause genetic damage to the cells on the surface of the deposited organ or tissue and can also penetrate the mucous membrane on the surface of the tissue or organ, causing damage to stem cells deep inside those tissues or organs (Zhuo et al. 2001; Kendall & Smith 2002; Darby et al. 2005; Alghamdi & Aleissa 2014). Meanwhile, some progenies are transferred to the body fluids through which they are transported to organs other than the respiratory organs, causing radiation damage to those organs. The ingestion of tap water with a higher 222Rn concentration was also associated with an increased risk of visceral disease, especially the incidence of gastric cancer and gastrointestinal cancer. Besides causing radiation damage to surface cells in the lining of digestive organs, 222Rn can also be absorbed by the gastrointestinal tract into body fluids and cause damage to other radiation-sensitive tissues or organs in the body. Therefore, the measurement and dose assessment of 222Rn and its progenies in tap water are of great significance in preventing random biological effects and improving public health (Kulali et al. 2019).

Many previous studies have calculated the effective inhaled or ingested dose of radon exposure due to domestic water (Binesh et al. 2012; Nita et al. 2013; Sharma et al. 2019). Nevertheless, the dose calculation of α- and β-particles to specific organs and tissues in the respiratory tract and alimentary tract is rarely involved, and the effect of temperature on radon concentration in water was not considered. In the present study, 222Rn concentrations in different tap water samples were measured, and the variation trend of 222Rn concentrations in tap water at different temperatures was analyzed. Based on the measurement results, the effective doses of α- and β-particles to the public were estimated using the human respiratory and alimentary tract model the human digestive tract model provided by ICRP.

Sample collection and determination of radon concentration

Urumqi River is the water source of Urumqi City in Xinjiang. The water supply plants in the city carry out centralized filtration and purification treatment for the river water and then transport it to the residents. In the study, 400 mL glass sampling bottles were used to collect indoor tap water from six residential areas in Urumqi. After the collection, the samples were sealed and brought back to the laboratory for radon concentration measurement under a constant temperature environment. Meanwhile, the collected water samples are heated to 25, 40, 55, 70, 85, and 100 °C in a constant temperature water bath with the same water bath time, and the radon concentration in the samples was measured at different water bath temperatures. All the measurements are completed on the same day of sampling.

The concentration of radon in the sample was measured by FD216, an environmental radon measurement instrument based on the scintillation chamber method, and its principle and structure are shown in Figure 1. Detailed experimental methods and procedures are described in the previous work (Yong et al. 2020).

Figure 1

Structure and principle of FD216 environmental radon concentration measuring instrument.

Figure 1

Structure and principle of FD216 environmental radon concentration measuring instrument.

Close modal

Estimation of radon and its progenies in the air

The transfer coefficient of radon in tap water diffusing into the air is calculated as follows:
formula
(1)
where is the concentration of radon in indoor air produced by water , f is the transfer factor, is the concentration of radon in tap water () (Nazaroff et al. 1987):
formula
(2)
where W is the per capita water consumption of residents , e is the release rate of radon from tap water into the air, with a value of 0.55, the ventilation rate of the dwelling is 0.68 , and V is the volume of the dwelling (Nazaroff et al. 1987).
The concentration of partial short-lived progenies of 222Rn diffused into the air using Equations (3) and (4):
formula
(3)
formula
(4)
where = 0, 1, 2, 3, 4, is the concentration of 222Rn in air , and is the concentration of 222Rn's th progeny in air , is the disintegration constant of the th progeny, is the ventilation rate of the dwelling , is the ratio of the concentration of the attached th progeny on aerosols to the total concentration of the attached and unattached radon progenies, = 0.9 and = = = 1, and are the deposition rates of the attached and unattached progenies, , and (Planinić et al. 1997; Misdaq et al. 2012).

Estimation of the committed effective dose of radon and its progenies

Figure 2 shows the human respiratory tract model and part of human digestive tract model provided by ICRP publication (ICRP 2015).

Figure 2

Compartment model representing time-dependent particle transport from each region. The transport rates shown alongside arrows are reference values in units of d−1, the combined model of the human respiratory tract and alimentary tract refers to ICRP Publication 130 (ICRP 2015).

Figure 2

Compartment model representing time-dependent particle transport from each region. The transport rates shown alongside arrows are reference values in units of d−1, the combined model of the human respiratory tract and alimentary tract refers to ICRP Publication 130 (ICRP 2015).

Close modal

Compartment ET1: retention of material deposited in the anterior nose (region ET1); compartment ETseq: long-term retention in airway tissue of a small fraction of particles deposited in the nasal passages (region ET2); compartment ET'2: short-term retention of the material deposited in the posterior nasal passage, larynx, and pharynx (ET2 region); compartment BB': retention of particles in the bronchial (region BB), with particle transport to ET'2; compartment bb': retention of particles in the bronchiole (region bb), with particle transport to BB'; compartment BBseq: long-term retention in airway walls of a small fraction of the particles deposited in the bronchiole (region bb); compartment bbseq: long-term retention in airway walls of a small fraction of the particles deposited in the bronchiole (region bb); compartment ALV: retention of particles deposited in the alveoli. INT: long-term retention of the particles deposited in the alveoli that penetrate to the interstitium: the particles are removed slowly to the lymph nodes (ICRP 2015).

The rate of change of the th decay progeny of 222Rn in the th compartment of the respiratory tract is given by the following equation:
formula
(5)
where is the radioactive activity of the th decay progeny of 222Rn in the th compartment of the respiratory tract, is the fractional deposition in the compartmentof the respiratory tract of different members of the public, . B is the average breathing rate for different members of the public . is the radioactive activity of the th decay progeny , , where is the clearance rate from regions n to i due to particle transport. , where is the clearance rate from regions i to n due to particle transport, is the fraction dissolved into the blood relatively rapidly, at a rate , is the fraction dissolved into the blood relatively slowly, at a rate . Except for the anterior nasal passage (ET1), the deposit from other regions of the respiratory tract is absorbed into the blood at a certain rate, and the dissolution rates of different radon progenies are different, in the process of 214Pb dissolving into the blood, a certain proportion of particles will first transform into ‘bound’ state. is the radioactive constant of the th decay progeny of 222Rn (ICRP 2002a, 2015; Misdaq & Flata 2003).
The rate of change of the th decay progeny of 222Rn in the th compartment of the alimentary tract is given by the following equation:
formula
(6)
where , is the transport rate from regions i to n, and is the rate of blood absorption in organ or tissue i, for material cleared from the respiratory tract to the alimentary tract, the fractional absorption in the alimentary tract is the product of and , where is the fractional absorption in the alimentary tract for relatively soluble forms of the element (ICRP 2015).
Then the committed equivalent doses of the th decay progeny of 222Rn in the target region T are given by the following equations:
formula
(7)
formula
(8)
where is the equivalent dose rate of the th decay progeny of 222Rn, is the radioactive activity of the th decay progeny of 222Rn in the target region T of the respiratory tract , is the radiation-weighting factor, α-particle is 20, β-particle is 1. is the joule to electron volt conversion factor, is the yield of the th decay progeny of 222Rn , is the energy of the th decay progeny of 222Rn , is the specific absorbed fraction, is the exposure time of the target region (ICRP 2016).
Equations (9) and (10) are used to calculate the committed equivalent dose of the extrathoracic region and the thoracic region, respectively. Equation (11) is used to calculate the committed equivalent dose of the colon region:
formula
(9)
formula
(10)
formula
(11)
where is the committed equivalent dose of the th decay progeny of 222Rn in the ET1 region, represents the ET1 region's estimated radiosensitivity relative to that of the whole organ, = = 0.001, = 0.998, = = = 0.333, = 0.001, = = 0.4, and = 0.2 (ICRP 1994, 2002a).
The committed effective dose of the th decay progeny of 222Rn is given by the following equation:
formula
(12)
where the tissue-weighting factor for is 0.025, the tissue-weighting factor for is 0.12, for organs of the alimentary tract other than the esophagus, the tissue-weighting factor is 0.12, while the tissue-weighting factor of the esophagus is 0.04 (ICRP 2002a).

According to the gastrointestinal system provided by ICRP Publication (ICRP 1979), as shown in Figure 3, the whole gastrointestinal system comprises five regions: stomach, small intestine, upper large intestine, lower large intestine, and blood.

Figure 3

Structure of the gastrointestinal system. The model refers to ICRP Publication 30 (ICRP 1979).

Figure 3

Structure of the gastrointestinal system. The model refers to ICRP Publication 30 (ICRP 1979).

Close modal
The rate of change of 222Rn in the th compartment of the alimentary tract is given by the following equation:
formula
(13)
where is the activity of 222Rn in the th compartment of the alimentary tract, is the transport rate from regions n to i, , is the transport rate from regions i to n and is the rate of blood absorption in the organ or tissue i, and is the radioactive constant of the 222Rn (ICRP 2015).
The committed equivalent doses of 222Rn in the tissue of the alimentary tract are given by the following equations:
formula
(14)
formula
(15)
where is the equivalent dose rate of 222Rn, 0.01 is assuming that only 1% of the contents of α-particle will cause a dose to any of the walls of the gastrointestinal tract, is the radioactive activity of 222Rn in the tissue T of the respiratory tract , is the radiation-weighting factor, is the electron volt to joule conversion factor, is the branching ratio for 222Rn disintegration, is the stopping power of the tissue T for the α-particles emitted by 222Rn , is the range of the α-particles emitted by 222Rn in the tissue of the target organ, is the mass of tissue T, and is the exposure time of the tissue T (ICRP 2002b).
The committed effective dose of the th decay progeny of 222Rn is given by the following equation:
formula
(16)

Radon concentration in residential tap water

The radon concentrations of tap water in residential buildings at different temperatures are shown in Table 1. The radon concentration of residential tap water ranges from 280 to 750 mBq L−1, with an average value of 548.16 mBq L−1, among them, the radon concentration of tap water sample L5 is the highest, and that of L6 is the lowest, which is 73820.2 and 2887.6 mBq L−1, respectively. Radon concentrations in all tap water samples were consistent with the USEPA's maximum contaminant level of 11.11 Bq L−1 and the drinking water radon parameter (100 Bq L−1) set by the EURATOM Drinking-Water Directive (USEPA 1999; Council Directive 2013/51/Euratom 2013). Radon concentrations in tap water in some countries and regions are shown in Table 2, and it is obvious that the measurement results of this study are within the range of those measured in these countries and regions (Sarrou & Pashalidis 2003; Marques et al. 2004; Rusconi et al. 2004; Pagava et al. 2008; Nita et al. 2013; Ahmad et al. 2015; Erdogan et al. 2015; Fakhri et al. 2015; Le et al. 2015).

Table 1

Radon concentrations (mBq L−1) of tap water in residential buildings

Sample codeTemperature (°C)Radon concentration (mBq L−1)
L1 24.5 376 ± 23.6 
L2 24.3 456 ± 15.0 
L3 24.8 720 ± 85.4 
L4 24.0 710 ± 17.3 
L5 24.4 738 ± 20.2 
L6 24.1 288 ± 7.6 
Average  548.16 
Sample codeTemperature (°C)Radon concentration (mBq L−1)
L1 24.5 376 ± 23.6 
L2 24.3 456 ± 15.0 
L3 24.8 720 ± 85.4 
L4 24.0 710 ± 17.3 
L5 24.4 738 ± 20.2 
L6 24.1 288 ± 7.6 
Average  548.16 
Table 2

Radon concentrations (mBq L−1) in tap water in different countries or regions

LocationRadon concentration (mBq L−1)References
Konya, Turkey 870–18,340 Erdogan et al. (2015)  
Minab, Iran 200–1,710 Fakhri et al. (2015)  
Ho Chi Minh, Vietnam 30–205 Le et al. (2015)  
Sungai Petani, Kedah, Malaysia 2,390–8,010 Ahmad et al. (2015)  
Cyprus 100–2,000 Sarrou & Pashalidis (2003)  
Brazil 340–510 Marques et al. (2004)  
Transylvania, Romania 1,200–4,500 Nita et al. (2013)  
Milano, Italy 390–690 Rusconi et al. (2004)  
Tbilisi, Georgia 3,000–5,000 Pagava et al. (2008)  
Urumqi, China 280–750 Present study 
LocationRadon concentration (mBq L−1)References
Konya, Turkey 870–18,340 Erdogan et al. (2015)  
Minab, Iran 200–1,710 Fakhri et al. (2015)  
Ho Chi Minh, Vietnam 30–205 Le et al. (2015)  
Sungai Petani, Kedah, Malaysia 2,390–8,010 Ahmad et al. (2015)  
Cyprus 100–2,000 Sarrou & Pashalidis (2003)  
Brazil 340–510 Marques et al. (2004)  
Transylvania, Romania 1,200–4,500 Nita et al. (2013)  
Milano, Italy 390–690 Rusconi et al. (2004)  
Tbilisi, Georgia 3,000–5,000 Pagava et al. (2008)  
Urumqi, China 280–750 Present study 

Variation of radon concentration in tap water at different temperatures

In this study, tap water samples from different residential buildings will be gradually heated to 25, 40, 55, 70, 85, and 100 °C by water bath heating. Radon concentrations at different temperatures are shown in Table 3. The radon concentration in the six groups of tap water samples showed an obvious downward trend on the whole with the increase of the water bath temperature. The average radon concentration at 25 °C was 543.33 mBq L−1, and it decreased to 116.11 mBq L−1 at 100 °C. The variation of the radon retention rate (radon concentration at a certain water bath temperature/initial radon concentration × 100%) in tap water at different water bath temperatures is shown in Figure 4, radon retention decreases with the gradual increase of temperature too, when the temperature reaches 100 °C, the average radon retention rate in the sample group is only 21.99%. The results indicate that heating tap water can effectively reduce the concentration of radon in water and reduce the harm of radon intake to public health.

Table 3

Radon concentrations (mBq L−1) of tap water in residential buildings at different temperatures

Radon concentration (mBq L−1)
Sample code25 °C40 °C55 °C70 °C85 °C100 °C
L1 370 ± 26.5 240 ± 10.0 187 ± 11.5 110 ± 10.0 120 ± 26.4 123 ± 5.8 
L2 453 ± 15.3 306 ± 25.1 267 ± 20.8 143 ± 5.8 163 ± 20.8 133 ± 58.5 
L3 723 ± 75.1 263 ± 20.8 297 ± 73.7 180 ± 17.3 210 ± 26.5 177 ± 25.2 
L4 700 ± 75.5 287 ± 30.6 213 ± 32.1 217 ± 64.3 237 ± 32.1 137 ± 37.9 
L5 730 ± 43.6 237 ± 30.6 260 ± 55.7 213 ± 20.8 213 ± 15.2 93 ± 25.4 
L6 283 ± 11.5 190 ± 10.0 137 ± 25.2 63 ± 20.8 77 ± 25.1 33 ± 15.2 
Average 543.33 253.89 226.67 154.44 170.00 116.11 
Radon concentration (mBq L−1)
Sample code25 °C40 °C55 °C70 °C85 °C100 °C
L1 370 ± 26.5 240 ± 10.0 187 ± 11.5 110 ± 10.0 120 ± 26.4 123 ± 5.8 
L2 453 ± 15.3 306 ± 25.1 267 ± 20.8 143 ± 5.8 163 ± 20.8 133 ± 58.5 
L3 723 ± 75.1 263 ± 20.8 297 ± 73.7 180 ± 17.3 210 ± 26.5 177 ± 25.2 
L4 700 ± 75.5 287 ± 30.6 213 ± 32.1 217 ± 64.3 237 ± 32.1 137 ± 37.9 
L5 730 ± 43.6 237 ± 30.6 260 ± 55.7 213 ± 20.8 213 ± 15.2 93 ± 25.4 
L6 283 ± 11.5 190 ± 10.0 137 ± 25.2 63 ± 20.8 77 ± 25.1 33 ± 15.2 
Average 543.33 253.89 226.67 154.44 170.00 116.11 
Figure 4

Variation of radon retention rate of tap water samples at different temperatures.

Figure 4

Variation of radon retention rate of tap water samples at different temperatures.

Close modal

Despite there were two different trends, the concentration of radon in the samples decreased after water bath heating. Due to the low initial radon concentration (the average value is 368.89 mBq L−1), the radon retention rates of samples L1, L2, and L6 decrease continuously from 40 to 70 °C and then change gently. However, the radon retention rate of samples L3, L4, and L5 (with an average radon concentration of 717.78 mBq L−1) with a high initial radon concentration decreased rapidly between 25 and 40 °C, and then the change was flat. The radon concentration and retention rate of the six sample groups increased slightly from 70 to 85 °C. Statistical analysis showed that there was no significant difference in the radon concentration value and the radon retention rate between 70 and 85 °C (p < 0.05).

The radon retention rates of all samples at different temperatures were fitted by the method of locally weighted regression (LOESS), as shown in Figure 5. When the water bath heating temperature changes from 25 to 70 °C, with the increase in temperature, radon retention decreases continuously, dropping to only about 30%. With the increase of water bath temperature, the declining trend of radon retention is gentle, and the fitting curve is flat between 70 and 85 °C, followed by a slow decline between 85 and 100 °C, which possibly was because blisters appeared in the heated samples as the water bath temperature increased, accelerating radon degassing in the water.

Figure 5

(a) Fitting curve of the change of radon retention rate of tap water samples at different temperatures. (b) Boxplot of radon retention rates at different temperatures.

Figure 5

(a) Fitting curve of the change of radon retention rate of tap water samples at different temperatures. (b) Boxplot of radon retention rates at different temperatures.

Close modal

Estimation of the committed equivalent and effective dose of residential tap water

The annual committed equivalent dose and effective dose of radon and its progenies in tap water to respiratory and alimentary tract organs or tissues were estimated.

According to the actual situation of resident residence, bathroom space is about 14 m3. Meanwhile, according to the actual water consumption habits of residents, the temperature of shower water is assumed to be 40 °C, 30 min of shower three times a week, the water consumption is about 0.36 m3·h−1, and the decay progenies of radon released into the air during the shower are attached to the particles with an activity median aerodynamic diameter (AMAD) of 1 μm. The annual drinking water quantity of adult residents is 500 L, and the tap water will be boiled and cooled for drinking, ignoring the part of the indoor air radon dissolves into the tap water during cooling, the study assumes that all the radon concentrations taken in are the values at 100 °C and appear in the stomach (UNSCEAR 2000; ICRP 2002a).

The committed equivalent dose of inhalation of α decay short-lived progenies (218Po and 214Po) and β decay short-lived progenies (214Pb and 214Bi) to the respiratory tract and alimentary tract target tissues during a shower is shown in Tables 46. The committed equivalent dose contribution of α-particles to ET1, ET2, BB, bb, and AI in the respiratory tissue regions was higher than that of β-particles. The committed equivalent doses of β-particles to the target tissues of the respiratory tract are close to each other in order of magnitude, and the committed equivalent dose to LNET and LNTH regions is higher than that of the α-particles. In the alimentary tract, the committed equivalent dose of 214Pb to the target tissues of the esophagus was higher than that of 214Bi, while that to other organs of the alimentary tract was lower than 214Bi.

Table 4

Annual committed equivalent dose due to inhalation of radon decay progenies 218Po, 214Pb, 214Bi, and 214Po during the bath to adult male respiratory target tissues

Sample codeDecay progenies of 222RnAnnual committed equivalent dose (μSv a−1)
ET1ET2LNETBBbbAILNTH
L1 218Po 125.65 1.21 1.84 × 10−8 0.26 2.19 9.86 × 10−2 0.83 × 10−8 
214Pb 0.98 5.48 × 10−2 2.53 × 10−4 3.59 × 10−3 1.94 × 10−3 5.88 × 10−4 2.63 × 10−5 
214Bi 0.48 2.34 × 10−2 6.88 × 10−4 2.14 × 10−3 1.34 × 10−3 7.77 × 10−4 1.08 × 10−4 
214Po 2.68 × 10−4 2.51 × 10−6 1.13 × 10−20 7.19 × 10−7 1.02 × 10−6 5.61 × 10−8 5.14 × 10−21 
L2 218Po 160.56 1.55 2.35 × 10−8 0.34 2.80 1.26 × 10−1 1.06 × 10−8 
214Pb 1.25 7.01 × 10−2 3.23 × 10−4 4.59 × 10−3 2.48 × 10−3 7.51 × 10−4 3.36 × 10−5 
214Bi 0.61 2.99 × 10−2 8.79 × 10−4 2.73 × 10−3 1.72 × 10−3 9.93 × 10−4 1.38 × 10−4 
214Po 3.42 × 10−4 3.21 × 10−6 1.45 × 10−20 9.19 × 10−7 1.31 × 10−6 7.17 × 10−8 6.57 × 10−21 
L3 218Po 137.87 1.33 2.02 × 10−8 0.29 2.41 1.08 × 10−1 0.91 × 10−8 
214Pb 1.08 6.02 × 10−2 2.78 × 10−4 3.94 × 10−3 2.13 × 10−3 6.45 × 10−4 2.89 × 10−5 
214Bi 0.52 2.57 × 10−2 7.54 × 10−4 2.35 × 10−3 1.47 × 10−3 8.52 × 10−4 1.18 × 10−4 
214Po 2.94 × 10−4 2.76 × 10−6 1.24 × 10−20 7.89 × 10−7 1.12 × 10−6 6.16 × 10−8 5.64 × 10−21 
L4 218Po 150.09 1.45 2.20 × 10−8 0.32 2.62 1.17 × 10−1 0.99 × 10−8 
214Pb 1.17 6.55 × 10−2 3.02 × 10−4 4.29 × 10−3 2.32 × 10−3 7.02 × 10−4 3.14 × 10−5 
214Bi 0.57 2.80 × 10−2 8.21 × 10−4 2.55 × 10−3 1.61 × 10−3 9.28 × 10−4 1.29 × 10−4 
214Po 3.20 × 10−4 3.00 × 10−6 1.35 × 10−20 8.59 × 10−7 1.22 × 10−6 6.71 × 10−8 6.14 × 10−21 
L5 218Po 123.91 1.19 1.81 × 10−8 0.26 2.16 0.97 × 10−1 0.82 × 10−8 
214Pb 0.97 5.41 × 10−2 2.49 × 10−4 3.54 × 10−3 1.91 × 10−3 5.80 × 10−4 2.60 × 10−5 
214Bi 0.47 2.31 × 10−2 6.78 × 10−4 2.11 × 10−3 1.32 × 10−3 7.66 × 10−4 1.06 × 10−4 
214Po 2.64 × 10−4 2.48 × 10−6 1.12 × 10−20 7.09 × 10−7 1.01 × 10−6 5.53 × 10−8 5.07 × 10−21 
L6 218Po 99.47 0.96 1.46 × 10−8 0.21 1.73 0.78 × 10−1 0.66 × 10−8 
214Pb 0.78 4.34 × 10−2 2.01 × 10−4 2.84 × 10−3 1.53 × 10−3 4.65 × 10−4 2.08 × 10−5 
214Bi 0.38 1.85 × 10−2 5.44 × 10−4 1.69 × 10−3 1.06 × 10−3 6.15 × 10−4 0.85 × 10−4 
214Po 2.12 × 10−4 1.99 × 10−6 0.89 × 10−20 5.69 × 10−7 0.81 × 10−6 4.44 × 10−8 4.07 × 10−21 
Sample codeDecay progenies of 222RnAnnual committed equivalent dose (μSv a−1)
ET1ET2LNETBBbbAILNTH
L1 218Po 125.65 1.21 1.84 × 10−8 0.26 2.19 9.86 × 10−2 0.83 × 10−8 
214Pb 0.98 5.48 × 10−2 2.53 × 10−4 3.59 × 10−3 1.94 × 10−3 5.88 × 10−4 2.63 × 10−5 
214Bi 0.48 2.34 × 10−2 6.88 × 10−4 2.14 × 10−3 1.34 × 10−3 7.77 × 10−4 1.08 × 10−4 
214Po 2.68 × 10−4 2.51 × 10−6 1.13 × 10−20 7.19 × 10−7 1.02 × 10−6 5.61 × 10−8 5.14 × 10−21 
L2 218Po 160.56 1.55 2.35 × 10−8 0.34 2.80 1.26 × 10−1 1.06 × 10−8 
214Pb 1.25 7.01 × 10−2 3.23 × 10−4 4.59 × 10−3 2.48 × 10−3 7.51 × 10−4 3.36 × 10−5 
214Bi 0.61 2.99 × 10−2 8.79 × 10−4 2.73 × 10−3 1.72 × 10−3 9.93 × 10−4 1.38 × 10−4 
214Po 3.42 × 10−4 3.21 × 10−6 1.45 × 10−20 9.19 × 10−7 1.31 × 10−6 7.17 × 10−8 6.57 × 10−21 
L3 218Po 137.87 1.33 2.02 × 10−8 0.29 2.41 1.08 × 10−1 0.91 × 10−8 
214Pb 1.08 6.02 × 10−2 2.78 × 10−4 3.94 × 10−3 2.13 × 10−3 6.45 × 10−4 2.89 × 10−5 
214Bi 0.52 2.57 × 10−2 7.54 × 10−4 2.35 × 10−3 1.47 × 10−3 8.52 × 10−4 1.18 × 10−4 
214Po 2.94 × 10−4 2.76 × 10−6 1.24 × 10−20 7.89 × 10−7 1.12 × 10−6 6.16 × 10−8 5.64 × 10−21 
L4 218Po 150.09 1.45 2.20 × 10−8 0.32 2.62 1.17 × 10−1 0.99 × 10−8 
214Pb 1.17 6.55 × 10−2 3.02 × 10−4 4.29 × 10−3 2.32 × 10−3 7.02 × 10−4 3.14 × 10−5 
214Bi 0.57 2.80 × 10−2 8.21 × 10−4 2.55 × 10−3 1.61 × 10−3 9.28 × 10−4 1.29 × 10−4 
214Po 3.20 × 10−4 3.00 × 10−6 1.35 × 10−20 8.59 × 10−7 1.22 × 10−6 6.71 × 10−8 6.14 × 10−21 
L5 218Po 123.91 1.19 1.81 × 10−8 0.26 2.16 0.97 × 10−1 0.82 × 10−8 
214Pb 0.97 5.41 × 10−2 2.49 × 10−4 3.54 × 10−3 1.91 × 10−3 5.80 × 10−4 2.60 × 10−5 
214Bi 0.47 2.31 × 10−2 6.78 × 10−4 2.11 × 10−3 1.32 × 10−3 7.66 × 10−4 1.06 × 10−4 
214Po 2.64 × 10−4 2.48 × 10−6 1.12 × 10−20 7.09 × 10−7 1.01 × 10−6 5.53 × 10−8 5.07 × 10−21 
L6 218Po 99.47 0.96 1.46 × 10−8 0.21 1.73 0.78 × 10−1 0.66 × 10−8 
214Pb 0.78 4.34 × 10−2 2.01 × 10−4 2.84 × 10−3 1.53 × 10−3 4.65 × 10−4 2.08 × 10−5 
214Bi 0.38 1.85 × 10−2 5.44 × 10−4 1.69 × 10−3 1.06 × 10−3 6.15 × 10−4 0.85 × 10−4 
214Po 2.12 × 10−4 1.99 × 10−6 0.89 × 10−20 5.69 × 10−7 0.81 × 10−6 4.44 × 10−8 4.07 × 10−21 
Table 5

Annual committed equivalent dose due to inhalation of radon decay progenies 218Po, 214Pb, 214Bi, and 214Po during the bath to adult female respiratory tract target tissues

Sample codeDecay progenies of 222RnAnnual committed equivalent dose (μSv a−1)
ET1ET2LNETBBbbAILNTH
L1 218Po 80.83 0.71 1.86 × 10−8 0.17 1.96 7.49 × 10−2 0.85 × 10−8 
214Pb 0.82 4.64 × 10−2 4.55 × 10−5 2.89 × 10−3 1.61 × 10−3 4.75 × 10−4 1.16 × 10−4 
214Bi 0.40 1.96 × 10−2 1.36 × 10−4 1.71 × 10−3 1.02 × 10−3 6.30 × 10−4 4.41 × 10−4 
214Po 2.24 × 10−4 2.34 × 10−6 1.14 × 10−20 5.54 × 10−7 9.07 × 10−7 4.27 × 10−8 5.25 × 10−21 
L2 218Po 103.14 0.90 2.38 × 10−8 0.22 2.51 9.58 × 10−2 1.09 × 10−8 
214Pb 1.05 5.93 × 10−2 5.82 × 10−5 3.70 × 10−3 2.06 × 10−3 6.07 × 10−4 1.48 × 10−4 
214Bi 0.52 2.51 × 10−2 1.74 × 10−4 2.19 × 10−3 1.317 × 10−3 8.05 × 10−4 5.63 × 10−4 
214Po 2.86 × 10−4 2.98 × 10−6 1.46 × 10−20 7.08 × 10−7 1.15 × 10−6 5.45 × 10−8 6.72 × 10−21 
L3 218Po 88.57 0.77 2.04 × 10−8 0.18 2.15 8.22 × 10−2 0.93 × 10−8 
214Pb 0.90 5.09 × 10−2 4.99 × 10−5 3.17 × 10−3 1.76 × 10−3 5.21 × 10−4 1.27 × 10−4 
214Bi 0.45 2.16 × 10−2 1.49 × 10−4 1.88 × 10−3 1.12 × 10−3 6.91 × 10−4 4.83 × 10−4 
214Po 2.45 × 10−4 2.56 × 10−6 1.25 × 10−20 6.07 × 10−7 9.95 × 10−7 4.68 × 10−8 5.77 × 10−21 
L4 218Po 96.42 0.84 2.22 × 10−8 0.20 2.34 8.95 × 10−2 1.02 × 10−8 
214Pb 0.98 5.54 × 10−2 5.45 × 10−5 3.46 × 10−3 1.92 × 10−3 5.67 × 10−4 1.38 × 10−4 
214Bi 0.41 2.35 × 10−2 1.63 × 10−4 2.04 × 10−3 1.22 × 10−3 7.53 × 10−4 5.26 × 10−4 
214Po 2.67 × 10−4 2.79 × 10−6 1.36 × 10−20 6.61 × 10−7 1.08 × 10−6 5.10 × 10−8 6.28 × 10−21 
L5 218Po 79.60 0.69 1.83 × 10−8 0.16 1.93 7.39 × 10−2 0.84 × 10−8 
214Pb 0.81 4.57 × 10−2 4.50 × 10−5 2.85 × 10−3 1.59 × 10−3 4.68 × 10−4 1.14 × 10−4 
214Bi 0.39 1.94 × 10−2 1.34 × 10−4 1.69 × 10−3 1.01 × 10−3 6.21 × 10−4 4.34 × 10−4 
214Po 2.21 × 10−4 2.31 × 10−6 1.13 × 10−20 5.46 × 10−7 8.94 × 10−7 4.21 × 10−8 5.18 × 10−21 
L6 218Po 63.91 0.55 1.47 × 10−8 0.13 1.55 5.93 × 10−2 0.67 × 10−8 
214Pb 0.65 3.67 × 10−2 3.61 × 10−5 2.29 × 10−3 1.27 × 10−3 3.76 × 10−4 0.92 × 10−4 
214Bi 0.31 1.55 × 10−2 1.08 × 10−4 1.35 × 10−3 0.81 × 10−3 4.99 × 10−4 3.49 × 10−4 
214Po 1.77 × 10−4 1.85 × 10−6 0.91 × 10−20 4.38 × 10−7 7.18 × 10−7 3.38 × 10−8 4.16 × 10−21 
Sample codeDecay progenies of 222RnAnnual committed equivalent dose (μSv a−1)
ET1ET2LNETBBbbAILNTH
L1 218Po 80.83 0.71 1.86 × 10−8 0.17 1.96 7.49 × 10−2 0.85 × 10−8 
214Pb 0.82 4.64 × 10−2 4.55 × 10−5 2.89 × 10−3 1.61 × 10−3 4.75 × 10−4 1.16 × 10−4 
214Bi 0.40 1.96 × 10−2 1.36 × 10−4 1.71 × 10−3 1.02 × 10−3 6.30 × 10−4 4.41 × 10−4 
214Po 2.24 × 10−4 2.34 × 10−6 1.14 × 10−20 5.54 × 10−7 9.07 × 10−7 4.27 × 10−8 5.25 × 10−21 
L2 218Po 103.14 0.90 2.38 × 10−8 0.22 2.51 9.58 × 10−2 1.09 × 10−8 
214Pb 1.05 5.93 × 10−2 5.82 × 10−5 3.70 × 10−3 2.06 × 10−3 6.07 × 10−4 1.48 × 10−4 
214Bi 0.52 2.51 × 10−2 1.74 × 10−4 2.19 × 10−3 1.317 × 10−3 8.05 × 10−4 5.63 × 10−4 
214Po 2.86 × 10−4 2.98 × 10−6 1.46 × 10−20 7.08 × 10−7 1.15 × 10−6 5.45 × 10−8 6.72 × 10−21 
L3 218Po 88.57 0.77 2.04 × 10−8 0.18 2.15 8.22 × 10−2 0.93 × 10−8 
214Pb 0.90 5.09 × 10−2 4.99 × 10−5 3.17 × 10−3 1.76 × 10−3 5.21 × 10−4 1.27 × 10−4 
214Bi 0.45 2.16 × 10−2 1.49 × 10−4 1.88 × 10−3 1.12 × 10−3 6.91 × 10−4 4.83 × 10−4 
214Po 2.45 × 10−4 2.56 × 10−6 1.25 × 10−20 6.07 × 10−7 9.95 × 10−7 4.68 × 10−8 5.77 × 10−21 
L4 218Po 96.42 0.84 2.22 × 10−8 0.20 2.34 8.95 × 10−2 1.02 × 10−8 
214Pb 0.98 5.54 × 10−2 5.45 × 10−5 3.46 × 10−3 1.92 × 10−3 5.67 × 10−4 1.38 × 10−4 
214Bi 0.41 2.35 × 10−2 1.63 × 10−4 2.04 × 10−3 1.22 × 10−3 7.53 × 10−4 5.26 × 10−4 
214Po 2.67 × 10−4 2.79 × 10−6 1.36 × 10−20 6.61 × 10−7 1.08 × 10−6 5.10 × 10−8 6.28 × 10−21 
L5 218Po 79.60 0.69 1.83 × 10−8 0.16 1.93 7.39 × 10−2 0.84 × 10−8 
214Pb 0.81 4.57 × 10−2 4.50 × 10−5 2.85 × 10−3 1.59 × 10−3 4.68 × 10−4 1.14 × 10−4 
214Bi 0.39 1.94 × 10−2 1.34 × 10−4 1.69 × 10−3 1.01 × 10−3 6.21 × 10−4 4.34 × 10−4 
214Po 2.21 × 10−4 2.31 × 10−6 1.13 × 10−20 5.46 × 10−7 8.94 × 10−7 4.21 × 10−8 5.18 × 10−21 
L6 218Po 63.91 0.55 1.47 × 10−8 0.13 1.55 5.93 × 10−2 0.67 × 10−8 
214Pb 0.65 3.67 × 10−2 3.61 × 10−5 2.29 × 10−3 1.27 × 10−3 3.76 × 10−4 0.92 × 10−4 
214Bi 0.31 1.55 × 10−2 1.08 × 10−4 1.35 × 10−3 0.81 × 10−3 4.99 × 10−4 3.49 × 10−4 
214Po 1.77 × 10−4 1.85 × 10−6 0.91 × 10−20 4.38 × 10−7 7.18 × 10−7 3.38 × 10−8 4.16 × 10−21 
Table 6

Annual committed equivalent dose due to inhalation of radon decay progenies during the bath to alimentary tract target tissues

Sample codeGenderDecay progenies of 222RnAnnual committed equivalent dose (μSv a−1)
OesophagusStomachSmall intestineRight colonLeft colonRectosigmoid
L1 Adult male 214Pb 4.27 × 10−3 1.13 × 10−3 4.23 × 10−5 1.78 × 10−6 2.54 × 10−7 3.45 × 10−8 
214Bi 3.20 × 10−3 1.75 × 10−3 5.97 × 10−5 4.28 × 10−6 6.27 × 10−7 8.73 × 10−8 
Adult female 214Pb 3.38 × 10−3 0.87 × 10−3 3.62 × 10−5 1.53 × 10−6 1.37 × 10−7 2.08 × 10−7 
214Bi 2.56 × 10−3 1.33 × 10−3 4.94 × 10−5 3.45 × 10−6 2.98 × 10−7 5.60 × 10−7 
L2 Adult male 214Pb 5.46 × 10−3 1.45 × 10−3 5.55 × 10−5 2.35 × 10−6 3.32 × 10−7 4.55 × 10−8 
214Bi 4.09 × 10−3 2.24 × 10−3 7.63 × 10−5 5.48 × 10−6 8.02 × 10−7 1.11 × 10−7 
Adult female 214Pb 4.31 × 10−3 1.11 × 10−3 4.63 × 10−5 1.96 × 10−6 1.75 × 10−7 2.63 × 10−7 
214Bi 3.27 × 10−3 1.70 × 10−3 6.32 × 10−5 4.43 × 10−6 3.82 × 10−7 7.12 × 10−7 
L3 Adult male 214Pb 4.69 × 10−3 1.24 × 10−3 4.77 × 10−5 2.02 × 10−6 2.85 × 10−7 3.91 × 10−8 
214Bi 3.51 × 10−3 1.92 × 10−3 6.55 × 10−5 4.69 × 10−6 6.88 × 10−7 9.59 × 10−8 
Adult female 214Pb 3.71 × 10−3 0.95 × 10−3 3.98 × 10−5 1.68 × 10−6 1.50 × 10−7 2.26 × 10−7 
214Bi 2.81 × 10−3 1.46 × 10−3 5.33 × 10−5 3.81 × 10−6 3.29 × 10−7 6.12 × 10−7 
L4 Adult male 214Pb 5.10 × 10−3 1.35 × 10−3 5.19 × 10−5 2.20 × 10−6 3.11 × 10−7 4.25 × 10−8 
214Bi 3.82 × 10−3 2.09 × 10−3 7.02 × 10−5 5.13 × 10−6 7.49 × 10−7 1.04 × 10−7 
Adult female 214Pb 4.03 × 10−3 1.04 × 10−3 4.33 × 10−5 1.83 × 10−6 1.63 × 10−7 2.46 × 10−7 
214Bi 3.05 × 10−3 1.59 × 10−3 5.90 × 10−5 4.13 × 10−6 3.50 × 10−7 6.69 × 10−7 
L5 Adult male 214Pb 4.21 × 10−3 1.12 × 10−3 4.29 × 10−5 1.76 × 10−6 2.51 × 10−7 3.41 × 10−8 
214Bi 3.15 × 10−3 1.72 × 10−3 5.88 × 10−5 4.22 × 10−6 6.18 × 10−7 8.61 × 10−8 
Adult female 214Pb 3.33 × 10−3 0.85 × 10−3 3.57 × 10−5 1.51 × 10−6 1.35 × 10−7 2.03 × 10−7 
214Bi 2.52 × 10−3 1.31 × 10−3 4.87 × 10−5 3.41 × 10−6 2.94 × 10−7 5.53 × 10−7 
L6 Adult male 214Pb 3.38 × 10−3 0.89 × 10−3 3.43 × 10−5 1.45 × 10−6 2.05 × 10−7 2.81 × 10−8 
214Bi 2.53 × 10−3 1.38 × 10−3 4.72 × 10−5 3.39 × 10−6 4.96 × 10−7 6.92 × 10−8 
Adult female 214Pb 2.67 × 10−3 0.68 × 10−3 2.86 × 10−5 1.21 × 10−6 1.08 × 10−7 1.63 × 10−7 
214Bi 2.02 × 10−3 1.05 × 10−3 3.91 × 10−5 2.73 × 10−6 2.36 × 10−7 4.44 × 10−7 
Sample codeGenderDecay progenies of 222RnAnnual committed equivalent dose (μSv a−1)
OesophagusStomachSmall intestineRight colonLeft colonRectosigmoid
L1 Adult male 214Pb 4.27 × 10−3 1.13 × 10−3 4.23 × 10−5 1.78 × 10−6 2.54 × 10−7 3.45 × 10−8 
214Bi 3.20 × 10−3 1.75 × 10−3 5.97 × 10−5 4.28 × 10−6 6.27 × 10−7 8.73 × 10−8 
Adult female 214Pb 3.38 × 10−3 0.87 × 10−3 3.62 × 10−5 1.53 × 10−6 1.37 × 10−7 2.08 × 10−7 
214Bi 2.56 × 10−3 1.33 × 10−3 4.94 × 10−5 3.45 × 10−6 2.98 × 10−7 5.60 × 10−7 
L2 Adult male 214Pb 5.46 × 10−3 1.45 × 10−3 5.55 × 10−5 2.35 × 10−6 3.32 × 10−7 4.55 × 10−8 
214Bi 4.09 × 10−3 2.24 × 10−3 7.63 × 10−5 5.48 × 10−6 8.02 × 10−7 1.11 × 10−7 
Adult female 214Pb 4.31 × 10−3 1.11 × 10−3 4.63 × 10−5 1.96 × 10−6 1.75 × 10−7 2.63 × 10−7 
214Bi 3.27 × 10−3 1.70 × 10−3 6.32 × 10−5 4.43 × 10−6 3.82 × 10−7 7.12 × 10−7 
L3 Adult male 214Pb 4.69 × 10−3 1.24 × 10−3 4.77 × 10−5 2.02 × 10−6 2.85 × 10−7 3.91 × 10−8 
214Bi 3.51 × 10−3 1.92 × 10−3 6.55 × 10−5 4.69 × 10−6 6.88 × 10−7 9.59 × 10−8 
Adult female 214Pb 3.71 × 10−3 0.95 × 10−3 3.98 × 10−5 1.68 × 10−6 1.50 × 10−7 2.26 × 10−7 
214Bi 2.81 × 10−3 1.46 × 10−3 5.33 × 10−5 3.81 × 10−6 3.29 × 10−7 6.12 × 10−7 
L4 Adult male 214Pb 5.10 × 10−3 1.35 × 10−3 5.19 × 10−5 2.20 × 10−6 3.11 × 10−7 4.25 × 10−8 
214Bi 3.82 × 10−3 2.09 × 10−3 7.02 × 10−5 5.13 × 10−6 7.49 × 10−7 1.04 × 10−7 
Adult female 214Pb 4.03 × 10−3 1.04 × 10−3 4.33 × 10−5 1.83 × 10−6 1.63 × 10−7 2.46 × 10−7 
214Bi 3.05 × 10−3 1.59 × 10−3 5.90 × 10−5 4.13 × 10−6 3.50 × 10−7 6.69 × 10−7 
L5 Adult male 214Pb 4.21 × 10−3 1.12 × 10−3 4.29 × 10−5 1.76 × 10−6 2.51 × 10−7 3.41 × 10−8 
214Bi 3.15 × 10−3 1.72 × 10−3 5.88 × 10−5 4.22 × 10−6 6.18 × 10−7 8.61 × 10−8 
Adult female 214Pb 3.33 × 10−3 0.85 × 10−3 3.57 × 10−5 1.51 × 10−6 1.35 × 10−7 2.03 × 10−7 
214Bi 2.52 × 10−3 1.31 × 10−3 4.87 × 10−5 3.41 × 10−6 2.94 × 10−7 5.53 × 10−7 
L6 Adult male 214Pb 3.38 × 10−3 0.89 × 10−3 3.43 × 10−5 1.45 × 10−6 2.05 × 10−7 2.81 × 10−8 
214Bi 2.53 × 10−3 1.38 × 10−3 4.72 × 10−5 3.39 × 10−6 4.96 × 10−7 6.92 × 10−8 
Adult female 214Pb 2.67 × 10−3 0.68 × 10−3 2.86 × 10−5 1.21 × 10−6 1.08 × 10−7 1.63 × 10−7 
214Bi 2.02 × 10−3 1.05 × 10−3 3.91 × 10−5 2.73 × 10−6 2.36 × 10−7 4.44 × 10−7 

Due to different respiratory rates (0.54 m3·h−1 for adult males and 0.39 m3·h−1 for adult females) and SAF, the committed equivalent dose contribution of short-lived progenies to all tissue regions of the adult male respiratory tract (except region LNTH) was higher than that of the adult female. In the alimentary tract, except for the rectosigmoid, the committed equivalent dose in the target region of other organs was higher in adult males than in adult females.

The average annual cumulative effective dose of the respiratory tract and digestive tract in males was 0.125 and 6.97 × 10−4 μSv a−1, respectively, and that of females was 0.104 and 5.43 × 10−4 μSv a−1. The average total annual committed effective dose was 0.126 μSv a−1 for adult male and 0.105 μSv a−1 for an adult female (as shown in Table 7), the annual committed effective contribution of sample group L2 to residents was the highest, and that of adult male and an adult female was 0.152 and 0.127 μSv a−1, respectively, and the annual committed effective dose of sample group L6 was the lowest, 0.094 and 0.078 μSv a−1, respectively, which were all lower than the upper reference value of about 10 mSv a−1 set by ICRP (ICRP 2014).

Table 7

Annual committed effective dose due to inhalation of radon decay progenies (218Po, 214Pb, 214Bi, and 214Po) during the bath

Sample codeGenderAnnual committed effective dose (μSv a−1)
Respiratory tractAlimentary tractTotal
L1 Adult male 1.18 × 10−1 6.58 × 10−4 1.19 × 10−1 
Adult female 0.99 × 10−1 5.13 × 10−4 0.99 × 10−1 
L2 Adult male 1.51 × 10−1 8.41 × 10−4 1.52 × 10−1 
Adult female 1.26 × 10−1 6.55 × 10−4 1.27 × 10−1 
L3 Adult male 1.30 × 10−1 7.22 × 10−4 1.30a × 10−1 
Adult female 1.08 × 10−1 5.62 × 10−4 1.09 × 10−1 
L4 Adult male 1.41 × 10−1 7.86 × 10−4 1.42 × 10−1 
Adult female 1.18 × 10−1 6.12 × 10−4 1.18 × 10−1 
L5 Adult male 1.16 × 10−1 6.49 × 10−4 1.17 × 10−1 
Adult female 0.97 × 10−1 5.05 × 10−4 0.98 × 10−1 
L6 Adult male 0.93 × 10−1 5.21 × 10−4 0.94 × 10−1 
Adult female 0.78 × 10−1 4.06 × 10−4 0.78 × 10−1 
Average Adult male 1.25 × 10−1 6.97 × 10−4 1.26 × 10−1 
Adult female 1.04 × 10−1 5.43 × 10−4 1.05 × 10−1 
Sample codeGenderAnnual committed effective dose (μSv a−1)
Respiratory tractAlimentary tractTotal
L1 Adult male 1.18 × 10−1 6.58 × 10−4 1.19 × 10−1 
Adult female 0.99 × 10−1 5.13 × 10−4 0.99 × 10−1 
L2 Adult male 1.51 × 10−1 8.41 × 10−4 1.52 × 10−1 
Adult female 1.26 × 10−1 6.55 × 10−4 1.27 × 10−1 
L3 Adult male 1.30 × 10−1 7.22 × 10−4 1.30a × 10−1 
Adult female 1.08 × 10−1 5.62 × 10−4 1.09 × 10−1 
L4 Adult male 1.41 × 10−1 7.86 × 10−4 1.42 × 10−1 
Adult female 1.18 × 10−1 6.12 × 10−4 1.18 × 10−1 
L5 Adult male 1.16 × 10−1 6.49 × 10−4 1.17 × 10−1 
Adult female 0.97 × 10−1 5.05 × 10−4 0.98 × 10−1 
L6 Adult male 0.93 × 10−1 5.21 × 10−4 0.94 × 10−1 
Adult female 0.78 × 10−1 4.06 × 10−4 0.78 × 10−1 
Average Adult male 1.25 × 10−1 6.97 × 10−4 1.26 × 10−1 
Adult female 1.04 × 10−1 5.43 × 10−4 1.05 × 10−1 

Table 8 shows the annual committed effective dose and annual committed equivalent dose caused by 222Rn in tap water entering the residents' gastrointestinal tract. The annual committed effective dose of sample group L3 is the highest, and that of sample group L6 is the lowest, which is 0.2722 and 0.0514 μSv a−1, respectively. Among all the regions of the gastrointestinal tract, the lower large intestine region had the highest average annual committed equivalent dose (1.4606 μSv a−1), followed by the upper large intestine region (1.1502 μSv a−1), and the small intestine region was the lowest (0.1424 μSv a−1).

Table 8

Annual committed equivalent and effective doses of radon in tap water to adult resident gastrointestinal tracts

Sample codeAnnual committed equivalent doses of 222Rn (μSv a−1)
Annual committed effective dose (μSv a−1)
StomachSmall intestineUpper large intestineLower large intestine
L1 0.1842 0.1513 1.2217 1.5514 0.1900 
L2 0.1991 0.1636 1.3208 1.6772 0.2054 
L3 0.2638 0.2167 1.7500 2.2223 0.2722 
L4 0.2041 0.1676 1.3538 1.7191 0.2105 
L5 0.1394 0.1145 0.9245 1.1740 0.1438 
L6 0.0498 0.0409 0.3302 0.4193 0.0514 
Average 0.1734 0.1424 1.1502 1.4606 0.1789 
Sample codeAnnual committed equivalent doses of 222Rn (μSv a−1)
Annual committed effective dose (μSv a−1)
StomachSmall intestineUpper large intestineLower large intestine
L1 0.1842 0.1513 1.2217 1.5514 0.1900 
L2 0.1991 0.1636 1.3208 1.6772 0.2054 
L3 0.2638 0.2167 1.7500 2.2223 0.2722 
L4 0.2041 0.1676 1.3538 1.7191 0.2105 
L5 0.1394 0.1145 0.9245 1.1740 0.1438 
L6 0.0498 0.0409 0.3302 0.4193 0.0514 
Average 0.1734 0.1424 1.1502 1.4606 0.1789 

In this study, the radon concentration in the tap water of six residential areas was measured, and the average radon concentration was 548.16 mBq L−1. All samples were under the radon concentration limits recommended by USEPA and EURATOM (11.11 Bq L−1 and 100 Bq L−1). Compared with the radon concentration in the tap water of other countries or regions, the radon concentration in this study is within the range of other measurement results. At the same time, the radon concentration and the retention rate under different temperatures were obtained by heating tap water in the water bath, and the radon concentration generally showed a downward trend with the increase in temperature. Finally, the dose calculation model provided by ICRP was used to estimate the dose of radon exposure in some water-use scenarios. In the process of the shower, the annual committed effective dose of radon progenies to the male respiratory tract and the alimentary tract is higher than that of female, and in the respiratory tract, the committed equivalent dose caused by α activities to the respiratory tract target tissue is higher than that of β activities, while the average annual committed effective dose of radon from drinking water ingestion to the resident gastrointestinal tract is 0.1789 μSv a−1. Urban water supply plants, therefore, can reduce the concentration of radon in the water source by centralized aeration, while residents can reduce the concentration of radon in the water by heating and degassing to avoid further increase of public exposure to radon.

The work is supported by the National Natural Science Foundation of China (Project No. 32060292). The authors are thankful to the Xinjiang Hongfu Nuclear Safety Technology Co., Ltd of China for providing facilities and support.

All relevant data are included in the paper or its Supplementary Information.

Alghamdi
A. S.
&
Aleissa
K. A.
2014
Influences on indoor radon concentrations in Riyadh, Saudi Arabia
.
Radiat. Meas.
62
,
35
40
.
Binesh
A.
,
Mowlavi
A. A.
&
Mohammadi
S.
2012
Estimation of the effective dose from radon ingestion and inhalation in drinking water sources of Mashhad, Iran
.
Iran. J. Radiat. Res.
10
(
1
),
37
41
.
Council Directive 2013/51/Euratom
.
2013
Laying down requirements for the protection of the health of the general public with regard to radioactive substances in water intended for human consumption
.
Off. J. Eur. Union L.
296/12
,
12
21
.
Darby
S.
,
Hill
D.
,
Auvinen
A.
,
Barros-Dios
J. M.
,
Baysson
H.
,
Bochicchio
F.
,
Deo
H.
,
Falk
R.
,
Forastiere
F.
,
Hakama
M.
,
Heid
I.
,
Kreienbrock
L.
,
Kreuzer
M.
,
Lagarde
F.
,
Mäkeläinen
I.
,
Muirhead
C.
,
Oberaigner
W.
,
Pershagen
G.
,
Ruano-Ravina
A.
,
Ruosteenoja
E.
,
Schaffrath Rosario
A.
,
Tirmarche
M.
,
Tomášek
L.
,
Whitley
E.
,
Wichmann
H. E.
&
Doll
R.
2005
Radon in homes and risk of lung cancer: collaborative analysis of individual data from 13 European case-control studies
.
Br. Med. J.
330
(
7485
),
223
226
.
Erdogan
M.
,
Manisa
K.
&
Tel
F.
2015
The measurement of radon activity concentrations in tap water in some dwellings of Konya province-Turkey
.
Carpathian J. Earth Environ. Sci.
10
(
1
),
273
278
.
Fakhri
Y.
,
Kargosha
M.
,
Langarizadeh
G.
,
Zandsalimi
Y.
,
Rasouli Amirhajeloo
L.
,
Moradi
M.
,
Moradi
B.
&
Mirzaei
M.
2015
Effective dose Radon 222 of the tap water in children and adults people; Minab City, Iran
.
Global J. Health Sci.
8
(
4
),
234
243
.
ICRP (International Commission on Radiological Protection)
1979
Limits for Intakes of Radionuclides by Workers
.
Pergamon Press
,
Oxford
.
ICRP Publication 30, Part 1. Annals of the ICRP
.
ICRP (International Commission on Radiological Protection)
1994
Human Respiratory Tract Model for Radiological Protection
.
Pergamon Press
,
Oxford
.
ICRP Publication 66, Annals of the ICRP
.
ICRP (International Commission on Radiological Protection)
2002a
Guide for the Practical Application of the ICRP Human Respiratory Tract Model
.
Pergamon Press
,
Oxford
.
ICRP Supporting Guidance 3, Annals of the ICRP
.
ICRP (International Commission on Radiological Protection)
2002b
Basic Anatomical and Physiological Data for Use in Radiological Protection: Reference Values
.
Pergamon Press
,
Oxford
.
ICRP Publication 89, Annals of the ICRP
.
ICRP (International Commission on Radiological Protection)
2007
Nuclear Decay Data for Dosimetric Calculations
.
Pergamon Press
,
Oxford
.
ICRP Publication 107, Annals of the ICRP
.
ICRP (International Commission on Radiological Protection)
2014
Radiological Protection Against Radon Exposure
.
Pergamon Press, Oxford.
ICRP Publication 126, Annals of the ICRP
.
ICRP (International Commission on Radiological Protection)
2015
Occupational Intakes of Radionuclides: Part 1
.
Pergamon Press
,
Oxford
.
ICRP Publication 130, Annals of the ICRP
.
ICRP (International Commission on Radiological Protection)
2016
The ICRP Computational Framework for Internal Dose Assessment for Reference Adults: Specific Absorbed Fractions
.
Pergamon Press
,
Oxford
.
ICRP Publication 133, Annals of the ICRP
.
Jantsikene
A.
,
Kiisk
M.
,
Suursoo
S.
,
Koch
R.
&
Lumiste
L.
2014
Groundwater treatment as a source of indoor radon
.
Appl. Radiat. Isot.
93
,
70
75
.
Kendall
G. M.
&
Smith
T. J.
2002
Doses to organs and tissues from radon and its decay products
.
J. Radiol. Prot.
22
,
389
406
.
Kulali
F.
,
Günay
O.
&
Aközcan
S.
2019
Determination of indoor radon levels at campuses of Üsküdar and Okan Universities
.
Int. J. Environ. Sci. Technol.
16
(
9
),
5281
5284
.
Nazaroff
W. W.
,
Doyle
S. M.
,
Nero
A. V.
&
Sextro
R. G.
1987
Potable water as a source of airborne 222Rn in U.S. Dwellings: a review and assessment
.
Health Phys.
52
(
3
),
281
295
.
Nita
D. C.
,
Moldovan
M.
,
Sferle
T.
,
Ona
V. D.
&
Burghele
B. D.
2013
Radon concentrations in water and indoor air in North-West regions of Romania
.
Rom. Rep. Phys.
58
(Supplement), 196–201.
Oner
F.
,
Yalim
H. A.
,
Akkurt
A.
,
Orbay
M.
&
Faculty
A.
2009
The measurements of radon concentrations in drinking water and the Yeşilirmak River water in the area of Amasya in Turkey
.
Radiat. Prot. Dosim.
133
(
4
),
223
226
.
Pagava
S.
,
Rusetski
V.
,
Robakidze
Z.
,
Farfán
E. B.
,
Dunker
R. E.
,
Popp
J. L.
,
Avtandilashvili
M.
,
Wells
D. P.
&
Donnelly
E. H.
2008
Initial investigation of 222Rn in the Tbilisi urban environment
.
Health Phys.
95
(
6
),
761
765
.
Planinić
J.
,
Radolić
V.
,
Faj
Z.
&
Šuveljak
B.
1997
Radon equilibrium factor and aerosols
.
Nucl. Instrum. Methods Phys. Res., Sect. A
396
(
3
),
414
417
.
Rusconi
R.
,
Forte
M.
,
Badalamenti
P.
,
Bellinzona
S.
,
Gallini
R.
,
Maltese
S.
,
Romeo
C.
&
Sgorbati
G.
2004
The monitoring of tap waters in Milano: planning, methods and results
.
Radiat. Prot. Dosim.
111
(
4
),
373
376
.
Sarrou
I.
&
Pashalidis
I.
2003
Radon levels in Cyprus
.
J. Environ. Radioact.
68
(
3
),
269
277
.
UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation)
2000
Sources and Biological Effects of Ionizing Radiation
.
UNSCEAR Report to the General Assembly
,
New York
,
United Nations
.
USEPA (United States Environmental Protection Agency)
1999
Technical Factsheet: Proposed Radon in Drinking Water Rule
.
USEPA
,
Washington, DC
.
Vinson
D. S.
,
Campbell
T. R.
&
Vengosh
A.
2008
Radon transfer from groundwater used in showers to indoor air
.
Appl. Geochem.
23
(
9
),
2676
2685
.
WHO (World Health Organization)
2009
Guidelines for Drinking-water Quality
.
WHO Press
,
Geneva
.
Yasouka
Y.
,
Ishikawa
T.
,
Tokonami
S.
,
Takahashi
H.
,
Narazaki
Y.
&
Sinogi
M.
2008
A case study on the effect of water from groundwater sources on indoor radon levels
.
J. Radioanal. Nucl. Chem.
275
(
1
),
165
172
.
Yong
J. L.
,
Feng
G. W.
,
Liu
Q.
,
Tang
C.
,
Wu
B. S.
,
Hu
Y. H.
,
Cai
C. L.
&
Mao
P. H.
2020
Radon concentration measurement and effective dose assessment in different brands of commercial bottled water produced in China
.
Water Suppl.
20
(
5
),
1581
1591
.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Licence (CC BY 4.0), which permits copying, adaptation and redistribution, provided the original work is properly cited (http://creativecommons.org/licenses/by/4.0/).