Situation Analysis And Source Identification Of Heavy Metals Pollution In The Urban Topsoil Of Yongkang City

As the foundation of human life and product,the urban soil was one of the most important parts of the urban ecosystem. Hourly human activity leaded distinguishing degree contamination in urban soil, which has had the negative influence to the stability of urban ecosystem and human health.In this paper, the research object was the topsoil of Yongkang City, which was divided into seven zones based on its survey region. 203 urban soil samples were collected, and 10 kinds of heavy metal elements were analyzed to assess the pollution characteristics and the pollution degree of heavy metals and to discuss their probable sources.The results of the study showed:1) The concentration characteristics of heavy metals in the urban topsoil of Yongkang city were analyzed using the statistical software Excel and SPSS. The results showed that the mean concentrations of heavy metalsAs, Co, Cr, Cu, Mn, Ni, Pb, Ti, V, Znwere6.569, 10.566, 119.552, 22.968, 528.506, 22.445, 37.669, 5751.805, 84.365, 90.246 mg/kg. The heavy metals distribution were not uniform in the study area, and the dispersion degree was large.2) weemployed the single factor evaluation and the Nemerow integrated pollute indexto investigate the pollution characteristics of heavy metal in Yongkang urban topsoil. The results showed that the contamination levelof heavy metals in study areas was slight in total, but it was heavy in local areas. The single factorintegrated pollute index order of different heavy metals was Cr>Ni>V>Co>Ti>Cu>Zn>Mn>Pb>As. And the Nemerow integrated pollute index order of different function zones was industrial zone > traffic zone >parkland zone>residential zone> woodland zone> municipal zone>cultivated land.3) Using the potential ecological harm index, the potential ecological harm of urban topsoil in Yongkang was estimated in the paper. Just pay close attention to the perspective of the potential ecological harm index of heavy metal elements, the potential ecological harmof heavy metals in study areas was slight in total,thepotential ecological harm indexorder of different heavy metals was As>Ni>Co>Cu>Pb>Cr>V>Ti>Zn>Mn. Focus on the perspective of the potential ecological harm index of different function zones, the topsoil heavy metal in Yongkang belonged to medium ecological harm, the ecological risk index was 50.173. And the ecological risk index order of different function zones was industrial zone >parkland zone> residential zone> traffic zone > municipal zone> woodland zone> cultivated land.4) The correlation analysis, principal component analysis and cluster analysiswere used to predicate the potential sources of heavy metals in the urban topsoil of Yongkang City. The results showed that Cr, Cu, Ni, Pb, Zn were mainly contributed fromhardware manufacturing industry and local transportation. As and V were derived from industrial and natural soil forming processes, while Co and Ti were mainly originated from hardware manufacturing industry.