ABSTRACT
Objective To investigate the distribution of gross α and gross β levels of centralized drinking-water of township in Beijing from 2018 to 2019, so as to carry out better monitoring and evaluating the radioactivity in water. Methods A total of 215 underground drinking water samples were collected from 12 districts of Beijing, then monitored and evaluated according to the Determination of gross alpha activity in water-thick source method EJ/T 1075—1998 and Determination of gross beta activity in water-evaporation method EJ/T 900—1994. Results The gross α level of centralized drinking water of township in Beijing was 0.050 (0.052) Bq/L, ranging from 0.001 to 0.210 Bq/L, and the gross β level was 0.048 (0.038) Bq/L, ranging from 0.002 to 0.261 Bq/L from 2018 to 2019. Gross α and gross β levels of all samples did not exceed the guidance value recommended by standards for drinking water quality. There was no significant difference in the distribution of gross α and gross β levels of samples of all districts from 2018 to 2019(P > 0.05), there were significant differences in the distribution of gross α and gross β levels of samples from different district in the same period (P < 0.05). And the levels of Miyun, Huairou and Shunyi in Chaobai River system were higher than other districts. Conclusion The distribution of radioactive background of centralized drinking-water of township in Beijing was mastered, which was in the normal range.
ABSTRACT
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.