某铀矿周围与对照区饮用水的放射性水平及其健康风险评估

Radioactivity levels and health risk assessment of drinking water around a uranium mine and control area

目的调查某铀矿周围与对照区(察布查尔县和乌鲁木齐市)饮用水的放射性水平并进行健康风险评估。方法完全随机采集2020—2022年某铀矿周围(51份)和对照区[(察布查尔县(73份)和乌鲁木齐市(52份)]的饮用水样品共176份,测定其总α和总β放射性水平及放射性核素238U、232Th、226Ra、40K的浓度。比较不同区域(铀矿周围、察布查尔县和乌鲁木齐市)、不同水源来源(地表水、地表水+地下水、地下水)、距铀矿不同距离(5、10、15、20、25 km)的饮用水的总放射性水平。采用美国国家环境保护局(USEPA)、国际放射防护委员会和WHO推荐的方法分别估算饮用铀矿周围和对照区饮用水所致成年人的年有效剂量;采用USEPA提出的致癌风险因子评估居民终身致癌风险。对不同区域、不同水源、距铀矿不同距离的饮用水样品的总放射性水平进行单因素方差分析,若分析显示差异存在统计学意义时,进一步采用最小显著性差异法进行多重比较。结果不同区域饮用水样品中总α和总β放射性水平差异均有统计学意义[(0.13±0.04)Bq/L对(0.12±0.08)Bq/L对(0.08±0.03)Bq/L,F=9.854,P<0.01]、[(0.17±0.06)Bq/L对(0.13±0.10)Bq/L对(0.10±0.03)Bq/L,F=10.522,P<0.01]。不同水源来源的饮用水样品中总α和总β放射性水平差异均无统计学意义(F=2.849、1.352,均P>0.05)。距铀矿不同距离的饮用水样品中总α和总β放射性水平差异均有统计学意义[(0.16±0.02)Bq/L对(0.07±0.02)Bq/L对(0.11±0.02)Bq/L对(0.15±0.03)Bq/L对(0.14±0.03)Bq/L,F=21.720,P<0.01]、[(0.24±0.04)Bq/L对(0.09±0.01)Bq/L对(0.19±0.01)Bq/L对(0.17±0.03)Bq/L对(0.13±0.04)Bq/L,F=46.364,P<0.01)。距铀矿5 km处的饮用水样品中总α和总β放射性水平均值均最高。176份饮用水样品的总α放射性水平均值为(0.11±0.06)Bq/L,0.5%的饮用水超过国家标准限值(0.5 Bq/L)。通过饮用水样品中总α放射性水平估算饮用该饮用水所致年有效剂量平均值为(0.040±0.003)mSv/年。通过饮用水样品中放射性核素238U、232Th、226Ra、40K浓度估算饮用该饮用水所致年有效剂量平均值分别为(0.030±0.004)、(0.018±0.003)、(0.084±0.04)、(0.005±0.003)mSv/年。饮用该饮用水所致居民终身致癌风险为1.75×10^(-13)~4.35×10^(-11)。结论某铀矿周围和对照区(察布查尔县和乌鲁木齐市)的饮用水放射性水平较低,饮用该区域饮用水所致年有效剂量和终身致癌风险较低,不会造成可观测到的不良健康效应,对周围居民所造成的健康风险较低。

Objective To investigate radioactive levels in drinking water around a uranium mine and control areas(Chabuchar County and Urumqi City)and conduct health risk assessment.Methods A total of 176 drinking water samples were randomly collected from the vicinity of a uranium mine(51 samples)and the control area(73 samples from Chabuchar County and 52 samples from Urumqi City)from 2020 to 2022.The radioactive levels of totalαand totalβand the concentrations of radionuclides 238U,232Th,226Ra,40K were determined.The total radioactive levels of drinking water from different areas(around the uranium mine,Chabuchar County,and Urumqi City),different water sources(surface water,surface water+groundwater,groundwater)and different distances from the uranium mine(5,10,15,20,25 km)were compared.Methods recommended by the United States Environmental Protection Agency(USEPA),the International Commission on Radiological Protection,and the World Health Organization were used to estimate the annual effective dose of adults exposed to drinking water in the vicinity of the uranium mine and control areas.Carcinogenic risk factors proposed by the USEPA were used to assess the lifelong carcinogenic risk of residents.Total radioactive levels were compared among drinking water samples from different regions,water sources,and distances from uranium mines through one-way ANOVA.Results that had statistically significant differences were further subjected to least significant difference test for multiple comparisons.Results The difference of totalαand totalβradioactive levels in drinking water samples from different regions were statistically significant((0.13±0.04)Bq/L vs.(0.12±0.08)Bq/L vs.(0.08±0.03)Bq/L,F=9.854,Ρ<0.01),((0.17±0.06)Bq/L vs.(0.13±0.10)Bq/L vs.(0.10±0.03)Bq/L,F=10.522,Ρ<0.01).There were no significant difference in totalαand totalβradioactive levels in drinking water samples from different water sources(F=2.849,1.352;bothΡ>0.05).The differences of totalαand totalβradioactive levels in drinking water samples with different distances from uranium deposits were statistically significant((0.16±0.02)Bq/L vs.(0.07±0.02)Bq/L vs.(0.11±0.02)Bq/L vs.(0.15±0.03)Bq/L vs.(0.14±0.03)Bq/L,F=21.720,Ρ<0.01),((0.24±0.04)Bq/L vs.(0.09±0.01)Bq/L vs.(0.19±0.01)Bq/L vs.(0.17±0.03)Bq/L vs.(0.13±0.04)Bq/L,F=46.364,Ρ<0.01).The average values of totalαand totalβradioactive levels in drinking water samples 5 km away from the uranium deposit are the highest.The average values of totalαradioactive level in 176 drinking water samples was(0.11±0.06)Bq/L,and 0.5%of drinking water exceeded the national standard limit(0.5 Bq/L).The average annual effective dose caused by drinking water is estimated to be(0.040±0.003)mSv/years according to the totalαradioactive level in drinking water samples.According to the concentrations of radionuclides 238U,232Th,226Ra,40K in drinking water samples,the average annual effective dose caused by drinking water were estimated to be(0.030±0.004),(0.018±0.003),(0.084±0.04),(0.005±0.003)mSv/years.The lifelong carcinogenic risk among residents caused by drinking this water ranged from 1.75×10^(-13)to 4.35×10^(-11).Conclusions The radioactive level of drinking water around a uranium mine and the control area(Chabuchar County and Urumqi City)is low,and the annual effective dose and lifelong carcinogenic risk caused by drinking water in this area are low,which will not cause observable adverse health effects,the health risk to the surrounding residents is low.