Pollution Characteristics and Risk Assessment of Heavy Metals in Soil in Urban Area of Tai'an.

In order to understand the characteristics of heavy metal pollution in soil in the urban area of Tai'an, the contents of 6 kinds of heavy metals in 30 soil samples were determined. The pollution status was evaluated by single factor pollution index method, Nemero comprehensive pollution index method, geological accumulation index method, and potential ecological risk index method. The results show that the average contents of As, Cd, Cu, Pb, Hg and Ni in soil are 6.72, 0.066, 20.33, 18.19, 0.031 and 19.92 mg/kg. The average contents of As, Cd, Cu, Pb and Ni are lower than the soil background value of Tai'an city and Shandong province. The average content of Hg is slightly higher than the soil background value of Tai'an city. The content of Hg is greatly affected by human activities, the spatial distribution is quite different. Except that the single factor pollution index of Hg is 1.03,the number of sampling points with serious pollution, moderate pollution, slight pollution, and no pollution accounts for 3%, 7%, 23%, and 67%, respectively. The average comprehensive pollution index of nemerol is 1.58-1.64, which belongs to the light pollution level as a whole. The accumulation of heavy metals in soil is light, and most of them are in a pollution-free state. The maximum geological accumulation index of Hg is 1.29,reaching medium pollution(grade 2). The range of comprehensive ecological risk index RI is 39.96-191.81, with an average value of 77.60. The comprehensive ecological risk level is slight, which is a low ecological risk area, and Hg is the main factor causing the risk. The content of Cu and Ni is low, and the enrichment is mainly controlled by soil parent material and natural process. Pb, Cd and As are mainly derived from natural background factors and partially affected by human activities. Hg pollution comes from the use of chemical fertilizer, plastic film and inorganic pesticides containing heavy metals, which is greatly affected by agricultural activities and residents' life. [ABSTRACT FROM AUTHOR]