2016—2020年四川省五市饮用水源地放射性水平监测与分析

Monitoring and analysis of radioactivity levels in drinking water sources in five cities of Sichuan province from 2016 to 2020

目的了解四川省成都、宜宾、绵阳、广元、乐山五个重点市水源地的放射性水平,评价其水源地辐射水平的安全性。方法于2016—2020年间对成都、宜宾、绵阳、广元、乐山五市饮用水源地进行布点、采样,并分析水中总α[参照《水中总α放射性浓度的测定厚源法》(EJ/T 1075-1998)]、总β[《水中总β放射性测定蒸发法》(EJ/T 900-1994)]、^(90)Sr[参照《水和生物灰中锶-90的放射化学分析方法》(HJ 815-2016)]、^(137)Cs[参照《水和生物样品样品灰中铯-137放射化学分析方法》(HJ 816-2016)]、^(226)Ra[参照《水中镭-226的分析测定》(GB 11214-1989)]、U[参照《环境样品中微量铀的分析方法(3激光荧光法)》(HJ 840-2017)]、Th[参照《食品安全国家标准食品中放射性物质检验天然钍和铀的测定》(GB 14883.7-2016)]的放射性水平。结果五市饮用水源地的总α放射性浓度范围值为0.011~0.076 Bq/L,总β放射性浓度范围值为0.027~0.098 Bq/L,^(137)Cs的放射性浓度范围值为0.21~0.45 mBq/L,^(90)Sr的放射性浓度范围值为1.0~2.4 mBq/L,^(226)Ra的放射性浓度范围值为6.1~16.0 mBq/L,Th的放射性浓度范围值为0.06~0.21μg/L,U的放射性浓度范围值为0.73~3.3μg/L。不同水源地、不同年份之间的总α、总β、^(90)Sr、^(137)Cs、^(226)Ra、U、Th放射性浓度之间的差异均无统计学意义(P>0.05),不同水期的总α、总β、^(90)Sr、^(137)Cs、^(226)Ra放射性浓度之间的差异均无统计学意义(P>0.05)。不同水期的U放射性浓度差异有统计学意义(H=16.53,P<0.05),不同水期的Th放射性浓度差异有统计学意义(H=15.61,P<0.05)。结论本次调查显示四川省成都、宜宾、绵阳、广元、乐山五个重点市饮用水源地的总α、总β、^(90)Sr、^(137)Cs、^(226)Ra、U、Th放射性水平,与1995年国家环境保护局发布的《中国环境天然放射性水平》中的相关数据处于同一水平,均在生态环境部辐射环境监测技术中心发布的2013—2021年全国辐射环境监测质量报告的数据范围内,五个重点市的水源地放射性水平处于安全水平。

Objective To understand the radioactivity levels of water source in five key cities of Chengdu,Yibin,Mianyang,Guangyuan,Leshan in Sichuan province,and evaluate the radiation safety of these water sources.Methods From 2016 to 2020,the measuring site selection,sampling and analysis were made for measuring the radioactivity levels of total alpha,total beta,^(90)Sr,^(137)Cs,^(226)Ra,U,Th in drinking water sources in these five cities.Reference was made,respectively,to the national standards Determination of totalαradioactivity concentration in water thick source method(EJ/T 1075-1998),Determination of totalβradioactivity in water evaporation method(EJ/T 900-1994),Radiochemical analysis method of strontium-90 in water and biological samples ash(HJ 815-2016),radiochemical analysis of cesium-137 in the ash of water and biological samples(HJ 816-2016),Analysis and determination of radium-226 in water(GB 11214-1989),Analysis of trace uranium in environmental samples-3 laser fluorescence law(HJ 840-2017),and Food safety in the test of radioactive substances in food determination of natural thorium and uranium(GB 14883.7-2016).Results The activity concentration ranges from 0.011 to 0.076 Bq/L for total alpha,0.027 to 0.098 Bq/L for total beta,0.21 to 0.45mBq/L for ^(137)Cs,1.0 to 2.4 mBq/L for ^(90)Sr,6.1 to 16.0 mBq/L for ^(226)Ra,0.06 to 0.21μg/L for Th,and 0.73 to 3.30μg/L for U.There were no significant differences in the concentrations of total alpha,total beta,^(90)Sr,^(137)Cs,^(226)Ra,U and Th in different water sources and different years(P>0.05).There were no significant differences in the concentrations of total alpha,total beta,^(90)Sr,^(137)Cs and ^(226)Ra during different water periods(P>0.05).There were statistical differences in U activity concentration in different water periods(H=16.53,P<0.05),and statistical differences in Th activity concentration in different water periods(H=15.61,P<0.05).Conclusions The survey showed that the total alpha,total beta,^(90)Sr,^(137)Cs,^(226)Ra,U and Th radioactivity levels in drinking water sources in Chengdu,Yibin,Mianyang,Guangyuan and Leshan of Sichuan province were at the same level as the relevant data in the Natural environmental radioactivity level in China published by the State Environmental Protection Bureau in 1995.All of there values were within the data range released by the 2013-2021 National Radiation Environment Monitoring Quality Report issued by the Radiation Environment Monitoring Technology Center of the Ministry of Ecology and Environment.The radioactivity level in water sources in the five key cities was at a safe level.