A Study On The Spatial Distribution Of Heavy Metal Elements And Source Apportionment Of Vanadium In Panzhihua Area Soil

Mining activities will have a serious impact on the ecological environment around the mine and the living environment of residents.Soil is necessary for agricultural production activities and it is also an important medium for people to rely on.The mining and smelting of ores will have a direct impact on the soil and may lead to serious heavy metal pollution.Panzhihua is one of the large mining bases in China and is famous for producing vanadium titanomagnetite.In the past half century,the mining industry has produced enormous economic benefits and irreversibly affected the surrounding environment of the mining area.Based on the project No.41273124 of the National Natural Science Foundation,And on the basis of evaluating the status of heavy metal pollution in Panzhihua area,the bioavailability of V element was evaluated by continuous form extraction method.At the same time,V isotopes ratios and V elements occurrence forms were used to trace the source of vanadium pollution.In this paper,This paper first applied V isotopes to the field of environmental geochemistry and used elemental morphologies for pollution trace studies.The final investigation and assessment of the soil pollution status and pollution sources in the Panzhihua area led to the following findings and conclusions:?1?The heavy metal pollution in Panzhihua soil was evaluated by the method of heavy metal pollution evaluation through the determination of heavy metal content in the soil of Panzhihua.In Panzhihua area,heavy metals are polluted to a certain extent,among which the content and pollution degree of As?Cr?Ti?V are relatively high.?2?the pollution of Cu and Cd in Lanjian mine area is slightly higher;Cd element in soil of Hemenkou area has been seriously polluted and the element of As?Pb has been polluted to some extent;the element of V?Ti is highly enriched in the area of vanadium plant;In Baoding coal mine area,the Cd and Cr elements in the soil were polluted to a moderate degree;and the pollution situation in Panzhihua Iron and Steel area was the most complex,all elements were polluted,and the pollution situation was the most serious in each district.?3?the occurrence forms of heavy metals in Panzhihua soil was studied by BCR method.The results showed that the bioavailability of heavy metals in Panzhihua soil was Ti<Cr<Cu<As<Zn<V<Pb from low to high.The average ratio of extractable states of the most unstable Pb elements is 32.7%.?4?The results of EDX analysis show that the soil is mainly composed of globular and irregular mineral aggregates,and its main chemical composition is O?Si?Al?Fe,so its mineral composition is mainly silicate minerals.?5?The vanadium isotope ratios in soil and some end components were determined and used to trace soil contamination.The results show that the range of?⁵¹V?‰?in soil is-0.620⁰.737.The composition range of the end component is-0.518⁰.941.Further analysis shows that the formation process of iron ore will produce V isotope fractionation,resulting in ⁵00 V enrichment in ore.V isotope will also produce strong fractionation during combustion of coal and blast furnace slag,resulting in light isotope enrichment in fly ash.?6?The V isotopic compositions of soil and end components are used for contamination tracing.It is concluded that the main anthropogenic source of vanadium pollution in surface soil of Panzhihua Iron and Steel area is the fly ash produced in smelting process,and the influence of coal fly ash is greater than that of blast furnace slag fly ash.The results show that the contribution rate of natural source is 51.20%,the contribution rate of coal fly ash is 46.92%,and the contribution rate of blast furnace slag fly ash is 1.88%.?7?The risk degree of vanadium in soil was evaluated in Pangang area,and the extractable state of V in Panzhihua Iron and Steel area was high.The proportion of extractable state in the profile increases with the depth of soil,which indicates that the proportion of extractable state of the end component of soil pollution is lower than that of the original soil.The pollution tracer was studied by using the extractable fraction of vanadium,and the results showed that the fly ash of burning coal was the main source of pollution.This conclusion is also consistent with the isotope analysis.