Distribution Characteristics Of Heavy Metals And Copper Isotope Tracing Technique In Mining Area Of Panzhihua

Heavy metal pollution mainly refers to the environmental pollution caused by heavy metals or their compound.The degree of the harm depends on the concentration and chemical forms of heavy metals in the environment,food and organisms.Panzhihua City is a large mining city of China.The development of minerals and industrial development for decades caused the prominent pollution problems on the city's soil and air.Therefore,to study the characteristics of heavy metal pollution in soil and air dust in Panzhihua City and trace its source of pollution can not only better grasp the current environmental level in the study area but also have important practical significance for improving the local soil and atmospheric environmental quality.The samples covered in this paper were collected from the Panzhihua area for a total of 81 samples.Combining methods and theories of environmental geochemistry,trace element geochemistry and mineralogy,comprehensive analysis and discussion were conducted on the heavy metal content,occurrence form,morphology,and composition characteristics of the samples to evaluate the heavy metal pollution in the study area.Based on this,combined with the Cu isotope characteristics of the samples,the trace sources of heavy metals in the study area were traced,and preliminary conclusions and understandings were obtained:I.Several heavy metals such as As,Cr,Cd,Cu,V,Ni,and Zn in air dust of Panzhihua Iron and Steel Zone have some degree of pollution.The As is more than doubled,and the highest is Cd,more than 10 times.The pollution levels of Cd,Cr,V and Zn even exceed the national soil level 3rd standard.While Cu also exceeds the national soil secondary standard,in which the local air pollution is a serious problem;II.Soil investigation results in several major industrial production areas and Hemenkou residential areas in the Panzhihua area shows that: In addition to As elements in the Baoding coal mine area,other elements exceed the soil background value of Sichuan Province.In addition to As and Cd,all other elements in vanadium plant area exceed the soil background value of Sichuan Province,where the main pollution elements are Cu and V.As for the Lanjian mining area,in addition to the As and Cr elements,all other elements exceed the background value of Sichuan Province,and the Ni element even exceeds the national secondary standard.The contents of the seven heavy metal elements investigated in Panzhihua Iron and Steel Plant Zone exceed the background value of Sichuan Province,in which the contents of Ni and V exceed the national secondary standard,and all of these elements cause the pollutions at different levels.The heavy metal pollution in the residential area of the Hemenkou is also serious.Where the contents of Cu and Ni are close to the background value of Sichuan Province,while the content of Zn exceeds the national secondary level standard and the contents of As and Cd have exceeded the national third level standard.The overall pollution degree in this area ranks only second to Panzhihua Iron and Steel Plant Zone;III.The occurrence forms of heavy metal in the soil samples are mainly as residue state,followed by the reducible and oxidizable states.The Zn element is worthy of attention in atmospheric dust,the proportion of weak acid extractable state accounts for 39%,should be concerned;IV.The particulates of atmospheric dust samples are mainly lumpy,flaky and spherical,mainly organic and metal oxides,and most shapes in the soil are irregular,mainly some silicate minerals;V.Through comparison,it was found that the major potential pollution originates from fly ash and dust removal ash.Moreover,the soil also shows a certain degree in the longitudinal direction;VI.After testing and analysis,it is found that the high temperature ashing method is not suitable for the digestion process of copper isotope analysis of samples based on the results of comparative isotope testing.The investigation and study of heavy metal pollution in soil and air through the above methods can provide a detailed understanding of the level of local heavy metal pollution,the environmental and local residents' potential threat factors,as well as the corresponding measures for control.