| The residential areas, cultural and educational areas, city parks, commercial areas, urban roads, industrial zones,development zones in Hohhot were taken as the research objects, the soil samples were randomly collected by triple subsampling technique in each functional zone. To investigate and analyze the heavy metal pollution in soil in different functional zones of Hohhot, the relationship of heavy metal was analyzed with Pearson correlation analysis, the pollution of heavy metal was assessed with Nemerow comprehensive pollution index, the sources of pollution were discriminated with principal component analysis.Contents of seven kinds of heavy metals were analyzed in different functional zones of Hohhot. The mean contents of heavy metals in soil samples exceeded the related background values in Inner Mongolia Autonomous Region. The mean contents of Cu and Zn were2.33and 1.85times respectively as high as those background values in soil in Inner Mongolia Autonomous Region. Single factor pollution index shows that different levels of Cr、 Cu、 Mn、 Zn in different functional zones of Hohhot. The Zn、 Cd、 Hg pollution was the severest among different functional zones and Ni、Pb、As was no pollution or light pollution. Average pollution levels of different heavy metal element is Cu>Zn>Cr>Mn>As>Ni>Pb. The Nemerow comprehensive pollution indexes ranked as follows:Commercial areas (3.03)> Urban roads (2.12)>Residential areas (1.98)> Cultural and educational areas(1.81)> Industrial zones(1.72)> Development zones (1.36)> City parks (1.28). The commercial district was heavily polluted and city parks pollution lightest. Correlation and Principal component analysis indicated that:9samples heavy metals could be classified into3classes: Cu Pb and Zn mainly come from transportation sources of pollution; Fe、 Cr and Mn is superimposed on the results of transportation、daily life and other human activities; Al、 Ni and As mainly governed by the soil parent material. |
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