RÉSUMÉ
Objective To investigate the radioactivity levels of total α and total β in drinking water in nine districts of Chongqing City from 2019 to 2021, and to provide reference for the risk monitoring of drinking water in the metropolitan areas of Chongqing. Methods The total α and total β radioactivity levels in water samples were determined by the comparative measurement method and the thin source deposit method in GB/T5750.13-2006 “Standard Examination Methods for Drinking Water-Radiological Parameters”. The monitoring results were assessed according to GB5749-2006 “Standards for Drinking Water Quality” and the fourth edition of the WHO Guidelines for Drinking Water Quality. Results From 2019 to 2021, the total α activity concentration of the water samples measured in the nine districts of metropolitan Chongqing ranged from 0.002 to 0.039 Bq /L, and the total β activity concentration ranged from 0.015 to 0.190 Bq /L. There was no significant difference in the activity concentration (tα=0.545, Pα=0.591; tβ=-1.438, Pβ=0.163>0.05). From 2019 to 2021, the average value of total α radioactivity decreased year by year and its activity value was relatively low, indicating a low health risk. However, the average value of total β radioactivity increased year by year, which should be paid attention to. Conclusion The total α and total β radioactivity in water samples measured in the present study are lower than the standard recommended limits. The estimated annual average effective dose of radiation caused by drinking water is 0.005-0.010 mSv, which is lower than the limit of 0.1 mSv recommended by WHO, and this radioactivity level will not have an impact on the health of residents. However, the total β radioactivity level of the monitoring points in Banan and Shapingba is relatively high compared to other jurisdictions, and further tracking and monitoring should be carried out.
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Objective:To investigate and analyze the level of the gross radioactivity, and its variation trend, in surrounding drinking water since the second phase expansion project at Qinshan Nuclear Power Plant was officially put into operation.Methods:From 2010 to 2022, the source water, factory water and tap water within 30 km of Qinshan Nuclear Power Plant were collected in the flood season (May) and dry period (October) every year. The total α and total β radioactivity concentrations in drinking water was measured and analyzed. The levels of total radioactivity in drinking water around different nuclear power plants in China and around non-nuclear power plant areas was compared.Results:The mean radioactivity concentrations of total α and total β were (0.021±0.019) and (0.204±0.058) Bq/L in source water, (0.010±0.005) and (0.185±0.056) Bq/L in factory water , and (0.012±0.007) and (0.170±0.058) Bq/L in tap water, respectively, all lower than the limits stipulated in the Sanitary Standards for Drinking Water. There were no significant differences in the monitoring result of betweem the three types of water samples both in the flood and dry periods ( P> 0.05). The total radioactivity level in drinking water around Qinshan Nuclear Power Plant site was close to that in drinking water around different nuclear power plants in China and around areas without nuclear power plants. Conclusions:Following the second phase of the expansion project officially being put into operation, the total α and β radioactivity level in drinking water around the Qinshan Nuclear Power Plant has been in a stable trend and lower than the guidance level given in national standard.
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Objective:To investigate the levels of gross radioactivity in drinking water in Hangzhou city before and after Qiandao Lake as the water source to the main urban area of Hangzhou.Methods:Since 2012, water samples were collected from water source, factory water and peripheral water in rainy and dry seasons, respectively, to determine their gross α and β activity concentrations for comparison and analysis.Results:The gross radioactivity levels in drinking water in Hangzhou are lower than the limits specified in the national standard "Standards for drinking water quality" (GB 5749-2006), without statistically significant difference for these water sources between the rainy and dry season ( P>0.05). The gross α(0.008±0.000)and gross β(0.034±0.013)levels in Qiandao lake were both less than those in Qiantang river ( Z=-3.235, -4.058, P<0.05), with significant difference ( Z=-2.181, -4.577, P<0.05). There was no significant difference in gross α and gross β in factory water and peripheral water before and after the operation of Qiandao Lake water supply project ( P>0.05). Conclusions:The gross radioactivity in drinking water in downtown Hangzhou are low from 2012 to 2020. The gross radioactivity levels in Qiandao Lake are lower than in the lower reaches of Qiantang river and Dongtiao steam. No impact was generated on radioactivity levels in drinking water after Qiandao lake supplied water to Hangzhou.
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Objective:To evaluate the impacts of radioactivity in foods since begining of the operation of the Hongyanhe Nuclear Power Plant (HNPP).Methods:The levels of radioactivity in foods collected within 30 km of HNPP from 2013 to 2020 were analyzed by comparison of the control samples and those collected before the operation. The impacts on the operation of the HNPP on foods were evaluated.Results:The man-made radionuclides such as 131I, 134Cs, 60Co, 58Co, 110Ag m were not found in food samples. The nautral radionuclides such as 238U, 226Ra, 232Th, 40K were at the normal levels, with the average levels of (0.088±0.053), (0.155±0.178), (0.314±0.388)and(81.3±18.1)Bq/kg(fresh weight)in foods, respectively. The average levels of man-made nuclide 137Cs in foods were (0.013±0.010) Bq/kg (fresh weight). There was no increase in radionuclide levels compared with the control samples and the samples before the operation. Conclusions:The impacts on foods due to the operation of HNPP was not found.
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Objective To investigate the food radioactivity levels in areas around the Xudabao nuclear plant before operation. Methods The food radioactivity levels were achieved by detecting samples collected within 30 km around the Xudabao nuclear power plant with a HPGe detector. Results The major radionuclides in food were 238U, 226Ra, 232Th, 40K and the man-made radionuclide of 137Cs. The average activity levels of natural 238U、226Ra、232Th、40K were(1.2 × 10−11 ± 2.6 × 10−11)、(9.2 × 10−12 ± 1.6 × 10−11)、(3.6 × 10−11 ± 6.5 × 10−12)、(9.0 × 101 ± 5.8 × 101)Bq/kg respectively. The average level of 137Cs in food was (1.2 × 10−12 ± 9.0 × 10−13)Bq/kg. Conclusion The man-made radionuclides were not detected except 137Cs in the collected food. The radioactivity concentrations were lower than the national standards. The effective dose for local residents by ingestion of 137Cs was around 6.0 × 10−12 µSv/a.
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Objective To investigate the radioactivity levels in foods in environmental protection area around a decommissioned uranium mine in Yunnan province,in order to timely discover the release of radioactive substances and to provide accumulated baseline data.Methods Radioactivity levels in grains,vegetables and fresh tea at 20 sampling points were measured in the environmental protection area within 3 km of a decommissioned the uranium mine.After field pretreatment and laboratory preparation,the radionuclides in samples were analyzed by means of γ spectrometry.Results Radionuclides in foods in the area mainly include natural radionuclides (238 U,232Th,226Ra,40 K) and man-made radionuclide (137 Cs).Radioactivity level of 238U,232Th,226Ra and 40K was (0.17 ± 0.05),(0.25 ± 0.17),(0.43 ±0.28)and (103.49 ±25.10)Bq/kg(fresh weight),respectively.Radioactivity levels of 232Th,226Ra,40K and 137Cs in fresh tea were all higher than those in grains and vegetables.Conclusions Radioactivity levels in foods around the area are lower than the relevant national limits.No man-made radionuclide other than 137Cs was found in the area.