| This thesis focuses its research on geochemical characteristics of soil environment in some region of Panzhihua of 900 square kilometers. At the same time, the author also determines geochemical baseline, and defines the geochemical indicators which are used to tell the influence of nature from that of human being on environment, on the basis of above, environmental analysis of heavy metal pollution is made. The main researching results are as follows: (1) With the use of Scan Electronic Microscope and X-ray diffraction analysis, it is determined that Xigeda formation clay of Panzhihua area is mainly composed of loamy sand and sandy loam, and that the main part of weathering pedogenesis of Xigeda formation petite, calcareous siltstone, and siltpelite is mechanical break. (2) A geochemical baseline for an element refers to its natural variations in concentration in the surficial environment and is the basis of environmental pollution analysis. With the use of normalization approach and statistically analyzing method, the environmental geochemical baseline of heavy metal elements such as As, Cd, Co. Cr, Cu, Ni, Pb, and Zn in topsoil (0-5cm ) and subsoil(3Ocm) of Panzhihua Xigeda formation clay is ascertained; at the same time, with the use of stratum comparison approach, the geochemical baseline of above elements in deep layer of Xigeda formation is also determined. It is shown that there exists some different among those geochemical baseline which is determined in different layer and in different approach. (3) The index of geoaccumulation is important parameter to assessing heavy metal pollution in soil and sediments. Through the Geoaccumulation Index calculation of elements such as Cr, Co, Ni, Cu, Zn, As, Cd, Pb in topsoil in Panzhihua region, it is shown that most elements are in contamination level of 1 to 2, uncontaminated/slightly contaminated; some elements are in contamination level of 2 to 3, slightly contaminated/moderately contaminated. According to the Geoaccumulation Index, the contamination degree from strong to weak in topsoil is: Cd> As> Zn> Pb> Co > Ni > Cr> Cu. Though the Geoaccumulation Index in deep stratum is greater than that in topsoil, the contamination level is roughly same, and the related order from strong to weak is: Ni > Zn> Pb> Cd> As> Co> Cu> Cr. In addition, selecting different geochemical baseline may influence the Index of Accumulation. (4) The Enrichment Factor of As, Cd, Co, Cr, Cu, Ni, Pb, Zn in uneven ground topsoil in Panzhihua region is greater in Baoding coal mine, Taiping coal mine, Panzhihua iron mine, Panzhihua smelting factory, Panzhihua tailing dam, which demonstrates the above regions are more seriously influenced by human activity, while at the same site, enrichment factor of farmland is greater than that of uneven ground, which shows that the elements in farmland is much influenced by human activity. (5) The total contamination degree of soil heavy metal in Panzhihua uneven ground is ?.09-?-2.35, most of parts is -2---2. The total contamination degree is greater than 0, which means that this region has been polluted, while the main polluted areas are centered on industrial and mining area such as Baoding coal mine, Taiping coal mine, Panzhihua iron mine, Panzhihua smelting factory, and Panhizhua tailing dam. The total contamination degree of heavy metal in topsoil of farmland is ?.97?-l .94, which is under...
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