2021年西北地区某市饮用水中3种金属及类金属的暴露状况及健康风险评估

Exposure condition and health risk assessment of three metals and metalloids in drinking water of a city in Northwest China in 2021

目的掌握西北地区某市饮用水中3种金属及类金属的暴露状况及通过饮用水途径对人体造成的健康风险,为饮用水的健康风险管理提供科学依据。方法根据2021年西北地区某市集中式供水工程供水范围设置114个监测点并分别于枯水期、丰水期各采集114份水样开展水质监测,按照GB 5749—2006《生活饮用水卫生标准》对水中3种金属及类金属的浓度进行达标评价,应用美国环境保护局(U.S.Environmental Protection Agency,US EPA)推荐的健康风险评价方法进行致癌风险评估。结果共监测水样228份,达标率为100.00%。3种金属及类金属的浓度中位数As为0.50×10^(-5)mg/L、Cd为0.25×10^(-5)mg/L、Cr^(6+)为2.00×10^(-5)mg/L,致癌健康风险水平从大到小依次为Cr^(6+)>As>Cd,Rc为3.77×10^(-5)。As的浓度水平和健康风险水平枯水期>丰水期,Cr^(6+)的浓度水平和健康风险水平丰水期>枯水期;As、Cr^(6+)的浓度水平和健康风险水平均为二次供水>末梢水>出厂水;Cd的浓度水平和健康风险水平地表水>地下水。不同水样类型、不同水期之间Cd的浓度水平和健康风险水平差异均无统计学意义(均P>0.05);不同水源类型之间As、Cr^(6+)的浓度水平和健康风险水平差异均无统计学意义(均P>0.05)。结论西北地区某市饮用水中3种金属及类金属含量均达标,致癌总风险值为10-5数量级,处于可接受范围。致癌健康风险最高的为Cr^(6+),其次是As,提示某市在今后的饮用水污染防治中要重视Cr^(6+)、As对人群健康的潜在危害,加强饮用水监测和评价。

Objective To master the exposure of three metals and metalloids in drinking water in a city in Northwest China,assess the health risks to human body through drinking water,so as to provide scientific basis for health risk management of drinking water.Methods According to the water supply scope of a centralized water supply project in a city in Northwest China in 2021,114 monitoring points were set up and 114 water samples were collected in the dry season and the wet season respectively for water quality monitoring.The three metals and metalloids in drinking water were evaluated according to the GB 5749-2006 Sanitary Standards for Drinking Water.The health risk assessment method recommended by U.S.Environmental Protection Agency(US EPA)was used for the carcinogenic risk assessment.Results A total of 228 water samples were monitored,and the standard-reaching rate was 100.00%.The median concentrations of the three metals and metallids were As 0.50×10^(-5) mg/L,Cd 0.25×10^(-5)mg/L,Cr^(6+)2.00×10^(-5)mg/L,and the carcinogenic health risk levels were Cr^(6+)>As>Cd,Rc was 3.77×10^(-5).The concentration level and health risk level of As in the dry season were higher than those in the wet season.The concentration level and health risk level of Cr^(6+)in the wet season were higher than those in the dry season.The concentration level and health risk level of As and Cr^(6+)were secondary water supply tap water>factory water.The concentration level and health risk level of Cd in surface water were higher than those in groundwater.There were no statistically significant differences in the concentration level and health risk level of Cd among different water sample type and water period(all P>0.05).There were no statistically significant differences in the concentration level and health risk level of As and Cr^(6+)among different water sources(all P>0.05).Conclusions The contents of three metals and metalloids in drinking water in a city in Northwest China is up to standard,and the total carcinogenic risk value is 10-5 orders of magnitude,which is in the acceptable range.The highest risk of carcinogenic health is Cr^(6+),followed by As,suggesting that the city should pay attention to the potential harm of Cr^(6+)and As to human health in the future prevention and control of drinking water pollution,and strengthen the monitoring and evaluation of drinking water.