RESUMO
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.
RESUMO
Objective:To investigate the total radioactivity in drinking well water around the Bayanwula uranium mine.Methods:Totally 174 samples of drinking well water and 5 samples of filtered well water from residential houses were collected during dry and wet seasons in 2020 around the Bayanwula uranium mine. Total α and total β radioactivity in dry season and wet season were analyzed for detrmining whether there were differences between them and the relation between total radioactivity with different locations away from the uranium center. The radioactivity in filtered drinking well water used in residential houses was also investigated. Radioactivity were measured and analyzed using low background alpha and beta radioactivity meters, and the data were analysed using SPSS analytical statistical method.Results:In the drinking well water around Bayanwula uranium mine, the activity concentrations of total α and β measured in dry season were 0.024-2.468 Bq/L with a mean of (0.605±0.507) Bq/L and 0.125-1.395 Bq/L with a mean of (0.420±0.235) Bq/L, respectively. The values measured in wet season were 0.049-2.988 Bq/L with a mean of (0.825±0.605) Bq/L for total α and 0.059-1.623 Bq/L with a mean of (0.506±0.265) Bq/L for total β, respectively. The average value of total radioactivity in water samples was lower within 10, 30 and 20 km of the uranium mine in the descending order.Conclusions:The radioactivity in well water around the Bayanwula uranium mine is high, with the total α and β in samples greater in wet season than in the dry season and without elevated levels as compared to the pre-mining background.