Characteristics of Heavy Metals in Street Dust from Typical Functional Zones of Nanjing and Their Potential Ecological Risk

Four typical functional zones ,i.e. traffic zone, commercial zone, industry zone and residential zone were selected in Nanjing city for street dust sampling .In each zone and site, dust samples were randomly collected for five times. The total heavy metals were determined by atomic absorption spectrometry. And the concentration enrichment ratio (CER) was used to assess the degree of heavy metal contamination affected by man-made pollution in the street dust. The results showed that the heavy metal pollution of street dust was evidently, especially for Cu, Pb and Zn. Heavy metals of street dust in Nanjing cause the middle potential ecological risk. The ecological risk assessment of Cu reveals a serious situation The ecological risk of these functional zones decrease with traffic zone > industry zone > commercial zone > residential zone. Heavy metals of street dust in traffic zone show good mixed progress. But those in commercial zone reveal distinct diversities.