Résumé
Objective To evaluate the current situation of radioactive contamination in the soil around a decommissioned uranium mine by combined determination of 210Pb and 210Po activity concentrations. Methods Soil samples were collected around a decommissioned uranium mine. 210Po and the 210Pb decay product 210Bi were plated on a copper sheet by self-deposition at a constant temperature. Gross α and gross β counts were measured using a low-background α/β counter. The activity concentrations of 210Pb and 210Po in soil were calculated. The radioactive contamination was evaluated using geological accumulation index. Results The activity concentrations of 210Pb and 210Po in the soil around the decommissioned uranium mine were 873.7-2315.5 and 956.0-2315 Bq·kg−1, respectively. The activity concentrations of 210Pb and 210Po in nearby farmland soil were 54.2-257.8 and 59.1-234.5 Bq·kg−1, respectively. Evaluation with the geological accumulation index showed that the level of nearby farmland contamination was 0-2, indicating zero to moderate radioactive contamination of the farmland. Conclusion The relatively high radioactivity around the decommissioned uranium mine requires attention to the transfer, diffusion, and ingestion of the uranium decay products 210Pb and 210Po in the surrounding soil to avoid radioactive contamination of the environment.
Résumé
210Po and 210Pb exist widely in nature, and they have strong toxicity and strong ionization ability, which can cause continuous harm to human health. Therefore, it is of great significance to determine the activity concentrations of 210Po and 210Pb in environmental samples and to evaluate their harmful effects on human health. This article reviews the research progress in analytical methods and measurement techniques of 210Po and 210Pb in environmental samples.
Résumé
Objective Collect and analyze data of radiation level of 210Po/210Pb in cigarettes in China, evaluate the internal radiation dose caused by smoking to Chinese smokers and compare it with other countries. Methods The radiation levels of 210Po/210Pb in cigarettes in domestic and foreign countries were summarized and analyzed, and the fractions of 210Po/210Pb in mainstream smoke were recommended, and the internal radiation doses to smokers in China were estimated. Results In 2015, there were 320 million smokers among aged 15 and above in China with an average smoking amount of 15.2 cigarettes per day. The average activities of 210Po/210Pb weighted by the number of cigarette brands were 28.2 mBq per cigarette and 39.3 mBq per cigarette respectively. The mainstream smoke fraction of 20% of 210Po was used to make the does estimation which was the mean value of the experimental results of simulator and volunteers, and that of 210Pb was 10% measured by simulators. Based on the average smoking amount per day and the number of smokers in China, the annual effective dose of current smokers in China is 126 μSv·a−1, and the collective effective dose is 40746 man·Sv. Conclusion The content of 210Po/210Pb in Chinese cigarettes is about 2～3 times that of other country's cigarettes. However, the fraction of mainstream smoke and dose conversion coefficient of 210Po/210Pb adopted in this paper are different from those in other literatures. Therefore, the estimated dose of 20 cigarettes for Chinese smokers is lower than that for smokers in some countries.
Résumé
Objective To investigate radioactive nuclide 210Po content in the diet of residents and internal irradiation dose caused by them. Methods The major food distribution market is selected, more than 50 kinds of food samples such as meat, vegetables, fruits, aquatic products, cereals, milk are collected, the combined method ofwet ashingand metal deposition is used to measure 210Po content of food samples, and analysis of monitoring data and estimationof irradiationexposure dose of residents caused by 210Po and their relative contribution are made. Results In the food samples, the specific activity of 210Po was 8.34 mBq/kg· fresh～16.9 Bq/kg· fresh, and the content of 210Po in hairtail was higher, its value was16.9 Bq/kg· fresh, which was higher than other freshwater fish. According to the data, the annual intake of residents was 108 Bq/person, and the annual effective dose of adult caused by 210Po was 129 μSv/a.The relatively large contribution were from flour (15.2%), eggs (22.0%), aquatic products (17.1%) and vegetable oil (18.1%). Conclusion The annual intake of 210Po for residents is lower than the current limit for adults of which the value is 2 200 Bq.