Study On Heavy Metal Pollution Of Road Dust In The Main Urban Area Of Harbin

Taking the road dust in the main urban area of Harbin as the research object,this paper investigated the heavy metals（Cu,Zn,Pb,Cr,Cd）and organic matter content.The spatial distribution of heavy metals was analyzed by spatial interpolation,and the sources of heavy metals were evaluated by correlation analysis and principal component analysis.By measuring the p H value of road dust,the physical and chemical properties of the dust in the study area were analyzed,and the collected road dust was divided into three particle size segments of 75-150μm,150-850μm,and 850-2000μm according to the particle size,and the differences in different functional areas were analyzed.The spatial distribution of particle size dust and its particle size effect were discussed.Finally,environmental pollution and ecological risk assessments are carried out for each functional area and road dust and heavy metals by using the land accumulation pollution index method and the potential ecological hazard index method.The following conclusions are drawn:（1）The content of heavy metals in road dust in each functional area of Harbin（green space,commercial area,residential area,main road,secondary road,and industrial area）is significantly higher than the environmental background value of heavy metals in soil in Harbin,and the average content is Pb(354.92 mg·kg^-1),Cr(220.29 mg·kg^-1),Zn(206.42 mg·kg^-1),Cu(200.18 mg·kg^-1),Cd(9.95 mg·kg^-1).（2）There is a significant positive correlation between heavy metal Cu,Zn and Pb,indicating that Cu and Zn are homologous and mainly come from traffic pollution sources.Industrial emissions and traffic activities have become the main sources of heavy metals in road dust in Harbin.（3）The p H value of road dust in Harbin is generally alkaline.The p H value of road dust in different functional areas has little difference in general.The highest p H value is located at the gas station,which is 8.01,and the p H value of green space is the lowest,which is 7.21,which is weakly alkaline.（4）The average pollution levels of heavy metals Cu,Zn,Pb,Cr,and Cd in road dust in Harbin are moderate/severe pollution,no/moderate pollution,heavy pollution,moderate pollution,and severe pollution levels,respectively.The order of accumulation pollution level of heavy metals is:Cd>Pb>Cu>Cr>Zn.The average value of the comprehensive potential ecological hazard index RI of different functional areas is:industrial area（2449.56）>green space（1948.73）>main road（416.13）>gas station（333.64）>commercial area（288.88）>residential area（222.15）>secondary road（214.38）.