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Objective:To explore whether or not radioactive wastewater leakage or overflow exists in the nuclear medicine decay pool after the 7·20 extraordinary rainstorm disaster and to analyze its causes, so as to provide scientific basis for the design, construction and maintenance of the nuclear medicine decay pool and the radiation protection management of nuclear medicine in the future.Methods:Three hospitals A, B and C where 131I therapy are being performed were selected in Zhengzhou city, Henan province. Sampling points were set based on the monitoring result of the environmental radiation level around the nuclear medical decay pool in line with the relevent standard method. Soil samples were collected at different depths. The 131I radioactivity level in the soil was measured using HPGe gamma spectrometer, with the measured result being processed and analyzed. Results:Except for Hospital B where no 131I was detected, different 131I activity concentrations were detected in the soil samples collected around the nuclear medicine decay pool at Hospitals A and C. The 131I activity concentrations ranged from 16.4 to 98 111.8 Bq/kg at Hospital A and from 10.6 to 7 176.6 Bq/kg at Hospital C. After a time period of decay, the repeated detection has shown that the 131I activity concentrations ranged from 1.3 to 17.0 Bq/kg at Hospital A and from 3.9 to 7.1 Bq/kg at Hospital C. The 131I activity concentration in the soil at the depth of 0-5 cm was higher than that at the depth of 5-10 cm soil at the same sampling point. The ratios of activity concentration of 131I between different depths ranged from 1.3 to 13.1, with the median value of 5.9. Conclusions:After the 7·20 extraordinary rainstorm disaster, the surrounding environment of nuclear medicine decay pools at a few hospitals was contamminated by 131I to some extent. To prevent the risk of leakage of radioactive wastewater, the safety evaluation and management of radiation protection should be made better with increased awareness during the design, evaluation, construction and use of nuclear medicine decay pools.
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Objective To investigate the content of thorium (Th) in surface water in Sichuan Province, China, and to evaluate Th-associated health risk via water intake for residents. Methods Twenty-three monitoring sections were set in main surface water bodies in Sichuan Province. From 2016 to 2021, the Th radioactivity level in the water bodies was measured during dry and normal-water seasons. The health risk of residents was evaluated by calculating radioactive Th intake from the surface water bodies combined with the use of a health risk assessment model. Results The Th radioactivity level of the surface water bodies in Sichuan Province was 0.02-0.67 μ./L. There was no significant difference in the Th radioactivity level of different years or different surface water bodies (P > 0.05). A significant difference was observed in the Th radioactivity level of different water seasons (P < 0.05). The total mean annual committed effective doses of Th in all age groups caused by drinking water and water immersion ranged from 3.14 × 10−8 to 8.75 × 10−7 Sv, all lower than the World Health Organization (WHO)-recommended reference level of 0.1 mSv. The overall carcinogenic risks for residents in all age groups ranged from 3.93 × 10−10 to 1.09 × 10−8, all below the most rigorous control limits issued by WHO and International Commission on Radiological Protection. Conclusion The Th-associated health risk via direct water intake and water immersion in main surface water bodies of Sichuan Province is at an acceptable level. Th in main surface water bodies of Sichuan Province is safe for all age groups.
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Objective To investigate the radionuclide content in food in Chongqing, China by conducting a survey on the radioactivity in food. Methods A total of 114 samples of vegetables, grain, milk powder, and tea were collected in Chongqing. The samples were dried, pulverized into powder, added into Marinelli beakers, and then measured for radionuclides using a high-purity germanium gamma spectrometer (GEM40P4-765). Results The mean activity concentrations of natural radionuclides 238U, 232Th, 226Ra, and 40K in food in Chongqing were (0.396 ± 0.510), (0.199 ± 0.296), (0.140 ± 0.209), and (119.250 ± 105.470) Bq/kg, respectively. The contents of radionuclides in different foods were significantly different (P < 0.05). The mean activity concentration of the artificial radionuclide 137Cs was (0.091 ± 0.308) Bq/kg, and the mean activity concentration of 90Sr measured in nine tea samples was (1.243 ± 0.860) Bq/kg. Conclusion The contents of radionuclides in food in Chongqing are lower than the national standard limits, but the safety of radioactivity in food still needs to be taken seriously, and long-term surveillance of radioactivity in food is needed.
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Objective To analyze the radionuclide levels in food and the committed effective dose due to food intake in residents around the Shidaowan Nuclear Power Plant (SNPP). Methods Daily food samples were collected within 30 km radius around the nuclear power plant in 2019—2022. The radioactivity levels before and after the operation of SNPP were determined. The data were combined with the dietary consumption of residents in Shandong province, China to estimate the committed effective dose. Results The radionuclides 238U, 232Th, 226Ra, and 40K in food were at normal background levels, and the average radioactivity was (0.062 ± 0.004), (0.121 ± 0.007), (0.162 ± 0.010), and (92.4 ± 5.5) Bq/kg fresh weight. Trace 137Cs and 90Sr were detected in some food samples and the average radioactivity was (0.047 ± 0.003) and (0.193 ± 0.200) Bq/kg fresh weight. The levels of radionuclides did not increase after the operation of SNPP compared with that before operation. The estimated committed effective dose in residents due to food intake was 0.205 mSv. Conclusion The radioactivity of food in the area around SNPP shows no difference before and after operation, and the dose burden is low in local residents.
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Objective To investigate and evaluate the changes in total α and total β radioactivity levels in drinking water in Beijing, China, 2012—2021. Methods The test results of total α and total β radioactivity levels at 14 monitoring sites from 9 groundwater sources and 5 surface water sources in Beijing, 2012—2021 were collected. The radioactivity levels in the two types of water sources were compared. Statistical charts were used to show the monitoring situation at sampling sites in different regions during different periods, and related issues were explored. Results The total α and total β activity concentrations measured at monitoring sites from some water sources in Beijing, 2012—2021, were less than the total α and total β guideline values specified in the Standards for Drinking Water Quality (GB 5749—2006) (total α: 0.5 Bq/L, total β: 1.0 Bq/L). The mean total α activity concentration in the groundwater was significantly higher than that in the surface water. The total α and total β radioactivity levels in the reservoir D in the surface water were slightly higher than those in the other surface water. Conclusion In the past decade from 2012 to 2021, the total α and total β radioactivity levels in some water sources in Beijing were generally in a good condition and fluctuated within the range of environmental background values, without significant changes on the whole.
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Objective:To investigate and analyze the radioactivity level of 90Sr in offshore seawater and seafood therein around Sanmen nuclear power plant (NPP) and to estimate the annual committed effective dose to local population from ingestion of 90Sr in seafood from 2015 to 2019. Methods:From 2015 to 2019, the offshore seawater and 3 kinds of marine products grown locally in Sanmen and consumed by local residents were collected for measurement of the level of 90Sr radioactivity. The committed effective doses to the local population were estimated based on monitoring result and consumption data on seafood in Zhejiang offshore. Results:The radioactivity concentrations of 90Sr ranged from 2.4 to 4.1 mBq/L in the seawater, close to the natural radioacrive background level and from 6.7×10 -2 to 1.3 Bq/kg in seafood, lower than the standard values specified in the "Limited concentrations of radioactive materials in foods" (GB 14882-94). Annual committed effective dose to the local population from 90Sr attributable to consumption of seafood in Sanmen County from 2015 to 2019 were 2.2×10 -4-4.2×10 -4mSv, respectively, far lower than the worldwide committed effective dose result ing from internal exposure. Conclusions:From 2015 to 2019, the radioactivity concentration of 90Sr in seawater and seafood are stable, with neglectable dose burden to the local population.
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Objective To understand the radioactivity level of food surrounding a uranium mine in Xinjiang, to supplement the baseline database of food radionuclides in Xinjiang, to analyze the content of radionuclides and to estimate the internal exposure dose of residents caused by dietary intake. Methods The specific activity of 238U, 232Th, 226Ra, 40K and 137Cs of interest nuclides was measured, statistically analyzed by high purity germanium γ spectrometer, and the annual effective dose of these nuclides was estimated. Results No nuclide 238U was detected in food samples from 2018 to 2020. The average activity concentration and detection rate of other radionuclides were 232Th: 0.428 ± 0.038 Bq/kg (18.3%)、226Ra: 0.477 ± 0.063 Bq/kg (38%)、40K: 162 ± 7 Bq/kg (100%)、137Cs: 0.071 ± 0.011 Bq/kg (29.6%). The annual effective dose of residents due to food radionuclides was about 0.198 mSv. Conclusion The radioactivity level of food in the vicinity of a uranium mining mountain in Xinjiang is within the national standard limit, and the average annual effective dose caused by the diet of residents is consistent with the report of UNSCEAR in 2000. The content of artificial radionuclide 137Cs detected in food samples will not cause harm to the health of residents.
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The investigation of environmental radioactivity level is an important basic work of ecological environment protection. It can provide basic data and scientific basis for the evaluation of radioactive environment quality and the formulation of radiation safety regulations and standards. Based on many years of practical experience of environmental radioactivity level investigation, combined with relevant regulations and standards, this paper summarizes the common investigation methods in the investigation and research of environmental radioactivity level at home and abroad, summarizes a set of environmental radioactivity level investigation scheme with strong applicability, and gives detailed suggestions on the ideas, methods, technical routes and other key points of the investigation scheme. The research results of this paper can provide a reference for the preparation of environmental radioactive level investigation scheme.
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Objective To investigate radioactivity levels in the main agriculture products around a uranium mine in Northern Guangxi.Methods The agriculture products and soil samples were collected and analyzed by using HPGe gamma ray spectrometer.Results The specific activity of 226Ra in radish (including leaf),radish leaves and radish,collected in one place,were 45.0,66.7 and 32.3 Bq/kg,respectively.Those of 226Ra and 23SU in the radish soil collected in the same place were 19 672 and 85 917 Bq/kg,respectively.The transfer coefficients of soil-to-radish and soil-to-leaves were 1.61 × 10-3 and 3.40 × 10-3,consistent with those reported in relevant literature.Radioactivity levels in agricultural products in another survey was in consistence with those in the national survey for food products.Radioactivity levels in soil elsewhere near the radish site was consistent with the results of the national soil radioactivive background survey.Conclusions The soil in this place has been contaminated by the nearby uranium mine.It is important to investigate this place further and take the necessary measures.