石家庄某地区大气降尘重金属污染特征与风险评价

Pollution characteristics and risk assessment of heavy metals in atmospheric dustfall in an area of Shijiazhuang

为了解石家庄某地区大气降尘中重金属的质量比及对环境和人体健康的风险水平,测定大气降尘中Cd、Hg、As、Pb、Cr、Cu、Ni、Zn的质量比,利用地累积指数评价法、潜在生态风险评价法和健康风险评价模型进行风险评价。结果显示:大气降尘重金属平均质量比由大到小依次为Zn(974.67 mg/kg)、Cu(640.28 mg/kg)、Cr(202.40 mg/kg)、Pb(91.08 mg/kg)、Ni(58.92 mg/kg)、As(19.27 mg/kg)、Cd(1.34 mg/kg)、Hg(0.11 mg/kg),重金属平均质量比超出全省土壤背景值8.26倍。重金属元素的污染程度由大到小依次为Cu、Cd、Zn、Hg、Pb、Cr、Ni、As。除了Cd为极强生态危害,Hg为很强生态危害,Cu为强生态危害外,其他元素均为轻微危害。研究区域内儿童和成人的致癌风险均在可接受范围,成人的非致癌风险可接受,但儿童的非致癌风险不可接受。

The purpose of this study is to clarify the mass ratio of heavy metals in atmospheric dust in a certain area of Shijiazhuang,and then reveal the degree of heavy metal pollution and its risk level to the environment and human health.In the study area,11 sampling points for atmospheric dustfall were set up.When setting up sampling points,factors such as the dominant downwind and upwind directions of key enterprises,and regional characteristics were taken into account comprehensively.The mass ratios of Cd,Hg,As,Pb,Cr,Cu,Ni and Zn in the fallout were measured.By using the geoaccumulation index evaluation method and the potential ecological risk evaluation method,the risk assessment of the environment was carried out.By using the health risk assessment model provided by the US EPA,the risk assessment of human health was carried out.The determination results show that the average mass ratio of heavy metals is Zn(974.67 mg/kg),Cu(640.28 mg/kg),Cr(202.40 mg/kg),Pb(91.08 mg/kg),Ni(58.92 mg/kg),As(19.27 mg/kg),Cd(1.34 mg/kg),Hg(0.11 mg/kg)in descending order.The average mass ratio of heavy metals is 8.26 times higher than the soil background value in the province,which is mainly affected by industrial and transportation activities.The calculation results of the geoaccumulation index evaluation method show that the pollution degree of heavy metal elements in descending order is Cu,Cd,Zn,Hg,Pb,Cr,Ni,As.The results of the potential ecological risk assessment of heavy metals show that except for Cd which is a very strong ecological hazard,Hg which is a strong ecological hazard,and Cu which is a strong ecological hazard,all other elements are slightly harmful.The results of the health risk assessment show that the carcinogenic risks of children and adults in the study area are within the acceptable range,the noncarcinogenic risks of adults are acceptable,but the noncarcinogenic risks of children were unacceptable.