Present Situation And Evaluation Of Heavy Metal Pollution In The Soils Of Nanning City

In this thesis, the present situation of heavy metals (Cu, Zn, Cd, Pb,Cr, As,Ni) pollution in the soils of Nanning city was investigated and evaluated. The results were showed as follows:1 .The paper discussed the pollution of Pb, Cd, As, Ni, Cr, Cu and Zn in the soil of Nanning city through field investigation method. The results showed that: Except pollution of Cr, Cu and Zn is clean or still clean, the soil was polluted by Cd, As, Ni and Pb.The pollution of Cd is the most serious, Cd which is middle degree is 23.91 percent of total soils, and Cd which attained low-degree is 41.31 percent of total soils. The next pollution is As. Attaining middle-degree is 10.87 percent of total soils and attaining low-degree pollution is 19.57 percent of total soils. The last is Ni, Attaining middle-degree pollution is 2.17 percent of total soils and attaining low-degree pollution is 4.35 percent of total soils. And Pb attaining low-degree is 2.17 percent of total soils.2.The fuzzy comprehensive assessment showed that attaining low-degree pollution is 45.65 percent of total soils, and the soils of Nanning city had been widely polluted by heavy metals.3.The fuzzy comprehensive assessment of the soils in different land use showed that the heavy metals pollution of the soils, which is the most serious, is industrial zone, and the next is agricultural zone, living zone and commercial zone; the last is preserved scenic zone.4.Through single factor assessment it can be showed that industrial soil had been completely polluted by Cd, and some soils of preserved scenic zone had been polluted by Cd. Most soil of industrial zone had been polluted by As. Some soils of agricultural zone and living zone had been polluted by As, and the soil of commercial zone and preserved sceniczone had not been polluted by As. Some soils of industrial zone had been polluted by Ni, and other soils of different land use had not been polluted. Only Naming smelted plant of industrial zone had been polluted by Pb, and others had not been polluted. The soil of different land use had not been polluted by Cu,Zn and Cr.5.Correlation analysis indicated that there were significant or highly significant positive correlations between Pb,Cu and Zn; Cu and As; Pb and Cd; Zn, As and Cr; Ni and As; Cr and Cu in soils except that of Ni and Pb or Pb and Cr. There were highly significant positive correlations between available and total contents of heavy metals except Zn and As.