典型金属冶炼城市降尘中重金属污染特征及风险评价

2021年1-3月,采集湖南省某典型金属冶炼城市不同功能区的降尘样品,分析测定了17种重金属元素含量,其中15种重金属元素含量超出了湖南背景值,分别为Ag、Fe、Cd、Ti、Sb、Tl、Pb、As、Zn、Cu、Mo、Ni、Cr、Ba、Mn。采用地累积指数法、潜在生态危害指数法和健康风险评价模型对大气降尘中重金属可能造成的生态风险和健康风险进行评价。结果表明:受长期的有色金属冶炼影响,Ag、Cd、Fe、Sb、Ti、Tl 6种重金属达到了极重度污染,Pb、As、Zn、Cu、Mo在中度污染程度以上。工业区的综合生态危害指数远高于工业居民混合区、工业农业混合区、居民区和交通区,达到了极强生态危害级别。健康风险评价结果显示:大气降尘中As和Pb存在非致癌风险,As、Cd和Ni存在致癌风险,且经口摄入是最主要的暴露途径。与青少年和儿童相比,大气降尘中重金属对成人造成的风险较高,且成年女性面临的风险高于成年男性。

Pollution Characteristics and Risk Assessment of Heavy Metals in Atmospheric Deposition from a Typical Metal Smelting City

Atmospheric deposition samples were collected from different functional areas of a typical metal smelting city in Hunan Province from January to March in 2021.The contents of 17 heavy metals were measured.Compared with the background values of Hunan Province,15 heavy metals,such as Ag,Fe,Cd,Ti,Sb,Tl,Pb,As,Zn,Cu,Mo,Ni,Cr,Ba,Mn exceed the standards.Geo-accumulation index,potential ecological hazard index and health risk assessment for the heavy metal pollution in atmospheric deposition were carried out.The results showed that Ag,Cd,Fe,Sb,Ti and Tl were seriously polluted,while Pb,As,Zn,Cu and Mo were moderately polluted,which might be influenced by the smelting activities.The comprehensive ecological hazard index of industrial area was extremely strong ecological hazard,which was much higher than the industrial-residential area,industrial-agricultural area,residential area and transportation area.The health risk assessment results showed that As and Pb in atmospheric deposition posed non-carcinogenic risk,and As,Cd and Ni had carcinogenic risk.Among the three exposure pathways,oral ingestion was the main exposure pathway.Compared with teenagers and children,the risk of heavy metals in atmospheric dust was higher for adults,and females were more sensitive than males.