Migration Characteristics Of Heavy Metals In The Soil-pasture System Around The Copper Mine Of Huogeqi In Inner Mongolia

Soil-Plant system is the important unit of the biosphere,once the system is polluted by heavy metals,not only the crops quality and products but also the environmental quality of atmosphere and water will be severely affected,and finally do harm to human health through food chain.The development activity of nonferrous metals mine is the main source of heavy metals pollution of mine areas.It is impossible for this kind of pollution to be restored by natural,and by artificial is also very difficult.Inner Mongolia has rich underground resources and the development activity of mine is located in grassland ecosystem,which has a lower anti-interference ability. So the mining area residents living environment and animal husbandry will be seriously affected by development,smelting and transportation of mining.Therefore,it is necessary to investigation and study the heavy metals pollution of Soil-Pasture system in Inner Mongolia grassland mining area.This dissertation takes Huogeqi copper mine area on the grassland ecosystem of Inner Mongolia as research areas to carry out field survey and collect pasture samples as well as rhizosphere soil samples from 12 sampling sites.Soil and pasture samples were pre-treatment by suitable method and ground to fine powder,then were digested using Microwave system.The contents of 7 kinds of heavy metals(Cr,As,Cu,Pb,Zn,Ni,Mn) in samples of soil and pasture were determined by Inductively Coupled Plasma and the content of Hg were by Double light digital mercury analyzer.The results indicted that the average concentrations of Cr,Hg,As,Cu,Pb,Zn,Ni and Mn of the soil were higher than the average concentrations of Inner Mongolia within the 500 meters of Huogeqi copper mining area.According to China Environmental Quality Standard for Soils,only As and Cu exceeded the threshold values of Class ?,and have caused harm to the environment.In addition,pasture from Huogeqi copper mine were seriously polluted by Pb, slightly polluted by Cr,Hg,As,Pb and Cu.At the same time,the migration characteristics of heavy metals in soil-pasture system was studied by using migration coefficient and enrichment factor.The results showed that the transfer factor of 7 kinds of heavy metal elements(except As)were greater than 1.The average value of Hg was 2.99,which was the largest of them.The migration coefficient of 8 kinds of heavy metals was ordered as Hg>Mn>Ni>Zn>Cr>Pb>Cu>As.In addition to Pb,the enrichment factor of 7 kinds of heavy metals(Cr,As,Zn,Mn,Cu,Ni and Hg)were less than 1.The enrichment coefficient of Pb was 1.98,which was the highest of them. While the value of Ni was only 0.11,which was the lowest of them.The enrichment coefficient of heavy metals was ordered as Pb>Zn>Cu>Cr>Hg>As>Mn>Ni.In short,the soil within the 500 meters of Huogeqi copper mining area were seriously polluted by As and Cu,which the content have exceeded the second national level soil standard.While aerial parts of pasture were seriously polluted by Pb and As,both of the pollution index was greater than 10.Whether the pasture which was contaminated will affect the health of cattle,sheep and human and the degree of the extent of impact remains to be further studied.