焦作市道路灰尘中重金属的污染评价与源解析

Pollution Assessment and Source Analysis of Heavy Metals in Road Dust in Different Functional Areas of Jiaozuo City

为深入了解该城市不同功能区道路灰尘中重金属的污染行为和污染源,该研究采用电感耦合等离子体质谱仪(ICP-MS)测定了焦作市住宅区、文教区、商业区和工业区4个功能区道路灰尘中重金属Cr、Ni、Cu、Zn、As、Cd和Pb的含量,并用直接测汞仪(DMA-80)测定4个功能区道路灰尘中Hg的含量。采用地累积指数法和潜在生态风险指数法评价重金属污染水平和潜在风险,进一步用正定矩阵因子分解法研究其污染源。结果表明,灰尘中不同重金属的平均含量分别为142.96、60.32、63.02、288.48、45.71、3.89、129.68和1.84mg/kg,分别是河南省土壤背景值的2.26、2.20、3.15、4.62、4.66、59.85、5.82、73.60倍。各功能区的重金属含量存在显著差异性,工业区明显高于住宅区、文教区和商业区。根据地累积指数I_(geo)值大小,焦作市道路灰尘中重金属的整体污染水平为Hg>Cd>Pb>Zn>As>Cu>Ni>Cr,Cd和Hg的污染程度远高于其他元素,达到极强污染程度。不同功能区灰尘中重金属综合潜在生态风险指数RI依次为工业区>商业区>文教区>住宅区,均已达到极强生态风险。PMF模型解析道路灰尘有4个污染源:工业生产、交通运输、复杂生活源和干湿沉降,其贡献率分别为33.61%、23.48%、27.80%和15.11%。

In order to gain insight into the pollution behavior and source analysis of heavy metals in road dust in different functional areas of cities,the concentrations of(Cr,Ni,Cu,Zn,As,Cd,and Pb)in road dusts were determined by inductively coupled plasma mass spectrometry(ICP-MS)in four different functional areas(residential district,cultural and educational district,business district,and industrial district)of Jiaozuo City,and the concentrations of Hg in road dusts were determined by direct mercury measurement(DMA-80).The pollution levels and potential ecological risk of heavy metals were assessed by the soil accumulation index and potential ecological risk index.The possible sources of heavy metals measured in the dust were identified by positive definite matrix factorization method.The results showed that average concentrations of Cr,Ni,Cu,Zn,As,Cd,Pb,and Hg in road dusts from different functional areas of Jiaozuo City were 142.96,60.32,63.02,288.48,45.71,3.89,129.68,and 1.84 mg/kg,which were 2.26,2.20,3.15,4.62,4.66,59.85,5.82 and 73.60 times of the soil background value in Henan Province,respectively.Heavy metal concentrations varied greatly in different functional areas,and industrial district had the highest total contents and the heaviest pollution.According to the values of I_(geo),the overall pollution level of heavy metals in road dust in Jiaozuo is Hg>Cd>Pb>Zn>As>Cu>Ni>Cr.The pollution levels of Cd and Hg are much higher than other elements,reaching a very strong pollution level.The comprehensive potential ecological risk index(RI)of heavy metals in dust in different functional areas all reached very strong levels,with an order of industrial district>business district>cultural and educational district>residential district.PMF model showed that there were four pollution sources of road dust:industrial production,transportation,complex living sources and dry and wet deposition,with contribution rates of 33.61%,23.48%,27.80%and 15.11%,respectively.