Geochemical Characteristics And Significance Of Soil Environment In Anning River Area,Panzhihua,Sichuan Province

Based on the large-scale land quality geochemical survey project in anning river area of panzhihua,this paper analyzed and studied 8 heavy metal elements including As,Cd,Cr,Cu,Hg,Ni,Pb and Zn in the research area,providing valuable reference for agricultural production and environmental protection.In panzhihua anling river area as the research area,this paper comprehensive study area geology,geomorphology,hydrology,soil type,etc,and use of the software of the test data are analyzed,in-depth study of the surface soil geochemical characteristics,the source of heavy metal,land quality,and provides the crops as the study area planning.The results of this paper are as follows:The average concentrations of As,Cd,Cr,Cu,Hg,Ni,Pb and Zn in the study area were 4.29,0.19,119.34,59.81,0.032,46.36,19.05 and 91.5mg/kg,respectively.The coefficient of variation of Ni,Cr,Cu,Zn and Pb in the geochemical index is between 0.6-1,indicating that these elements are evenly distributed in the soil.The change coefficients of geochemical indexes of As and Hg were between 1?1.5,indicating that the above geochemical indexes were not evenly distributed in the soil.The change coefficient of Cd geochemical index was greater than 1.5,indicating that Cd was not evenly distributed in the soil,and the concentration clark value was as high as 5.135,indicating a high concentration of elements.Eight kinds of heavy metal element geochemical map in the study area shows that heavy metal anomaly distribution without rules,but anomaly distribution of heavy metals and PH has a high degree of correlation,anomaly appeared in the PH of the alkaline region,soil alkaline region in the evolution process of heavy metals to remain in place,so most of the heavy metals in the study area anomalies related to soil organic;The correlation analysis showed that cr-ni-cu-as heavy metal elements had strong correlation,mainly inherited the basic properties of soil parent material.Some of the heavy metal elements of Zn-Pb-Cd come from human activities.Hg is mainly derived from atmospheric deposition.The principal component analysis showed that Cu,Cr,As and Ni in the surface soil were from the parent material of soil,and pb-znwas formed by tailings pollution near the smelting plant.The results of r-type cluster analysis showed that Cr-Ni-Cu was mainly controlled by the parent material of soil.As,Cd,Zn and Pb are mainly residual in surface soil after weathering of carbonate rocks under supergene conditions.The evaluation results of soil heavy metal pollution were As follows: the single-factor index method showed that the content of the single-factor index of As,Cd,Hg,Pb and Zn was almost all clean and pollut-free at Pi?1,and Cr,Cu and Ni were the three heavy metal elements.The percentage of single-factor evaluation index is almost all between 1 Moderate pollution and severe pollution of eight heavy metal elements are very few and almost none.According to the comprehensive pollution index method of nimerow,80.68% of the surface soil had no pollution,12.71% of the surface soil was mildly polluted,4.55% of the surface soil was moderately and 2.07%of the surface soil was severely polluted.The soil accumulation index method shows that the pollution of heavy metal elements in the surface soil of the study area is not caused by human activities.