| Accompanied by rapid economic development, China’s urbanization and industrialization had led to a series of social and ecological problems, and these problems are becoming an obstacle to restrict the urban development. So urbanization and urban issues had become the one of the hot issues of geography, sociology, economics,urban planning and many other subjects.Chinese soil by the heavy metal pollution became the growing phenomenon, thereby endangering human health. Carrying out the study of urban soils can effectively control the deterioration of the urban soils’quality, improve the urban ecosystem function, and have the important practical significance for improving the quality of living environment.This paper aimed to discuss Yongkang city soil. Based on the element testing of169soil samples in suburban, with qualitative and quantitative method, this research comprehensively analysis the content, spatial distribution, affecting factors about heavy metal elements in Yongkang city, evaluate the pollution levels and the potential ecological hazards of heavy metals, and preliminary analyze the possible sources of heavy metal contamination of urban soils. The main conclusions are as follows:(1) The average content of heavy metal elements Mn, Cr, Co, Ni, Cu, Pb, Ti, Fe was670.35mg/kg,55.78mg/kg,12.44mg/kg,17.82mg/kg,34.62mg/kg,36.09mg/kg,4294.99mg/kg,31.8g/kg. The degree of dispersion of heavy metals was in a strong variation, especially Cu (the coefficient of variation of152.93%), the other elements were also in medium variation. Compared with the soil background of Jinhua and Quzhou Basin, the order of heavy metal elements concentration was Cu>Mn>Co>Fe>Cr>Pb>Ni>Ti, and the enrichment of heavy metals in the industrial zone samples revealed a higher degree in Yongkang City. According to element enrichment status and the National Soil Environmental Quality Standards, the heavy metal pollution levels were overall light, but the local was in serious trend in Yongkang city.(2) Geostatistical module analysis revealed that the heavy metal content showed some spatial variation in Yongkang City:Mn decreased from west to east; of Ti decreased from northeast to west south; Co was slightly higher in the northeast and southwest than the other regions; Pb had multiple high-value,such as in xibei industrial zone, steel sea group industrial zone and so on; Fe had a number of high-value areas, which were located along the jiuling middle road, Hardware City; the high value of the Cr content was located in the Xishan Tau industrial area, and the overall showed the trend which decreased frow west to east; the high value of the Ni content distributed in the the Xishan Tau industrial area and the Hardware City, but the trend was light in the whole; the high value of the content of Cu is located in the Xishan Tau industrial area, the overall showed the trend which increased frow northeast to southwest.(3) Through the correlation analysis between the soil properties and heavy metals showed that pH and Mn content showed highly significant positive correlation; Fe, Ti mainly enriched in the soil clay section, and part of them in the fine sand component; magnetic susceptibility had a good indication to Cu, Cr, Pb and other heavy metal pollutions.(4) Using the index method (single-factor pollution index and Nemerow pollution index method), the potential ecological risk index assessment method and factor analysis analyzed the degree of soil pollution, pollution sources in Yongkang city. The pollution evaluation showed Yongkang city soil had been polluted to different degrees and had the potential ecological risk of moderate-intensity, Cu pollution as the most serious. Factor analysis results showed that Cr, Ni, Cu, Pb, Mn were from the local hardware manufacturing and transportation, the contribution rate of41.002%; Fe, Ti, Co were mainly from the process of soil accumulated contributions, the contribution rate of28.507%, but Fe had mixed sources, partly from metal production. |
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