Pollution Characteristics Of Heavy Metal In Soil-crops System In Typical Lead-zinc Mines Of Guizhou Province

Heavy metal contamination and countermeasure in mine soil have always been one of the difficult and hot spots in environmental science and technology research.To study correlation between plants and soil of four typical lead-zinc zones within the boundaries of Guizhou province,heavy metals Cu,Zn,Pb,Cd,Cr,As and Hg were chose as researching objects in this paper.After fieldwork and screening of interesting areas,76 soil and 35 plant samples were collected and heavy metal contents in them were determinated with use of field sampling system analysis and aid of AA800,F-640 and ICP.Methods single-factor pollution index,integrated pollution index, and enrichment coefficient were used to systematically study heavy metal pollution status and accumulation characteristics of the soil and plants,the results showed that:(1) There existed a great difference in heavy metal pollution in mines and Cu,As and Cr appeared light pollution or even no pollution while Cd,Zn,Hg and Pb has approved pollution.(2) Integrated pollution index of heavy metal in the four interesting soil was greater than 3,leveled as serious contamination.(3) Single factor pollution index of heavy metal Cu and As in rice grains,corn was less than 1 while that of Pb,Cr,Hg and Cd greater than 2.Except for Cu,As,Zn,other heavy metal contents in rice seeds and corn showed significant correlation with the corresponding ones in soil which indicated that these elements migrated and accumulated more easily from soil to plants.Integrated pollution index of rice seeds and corn was greater than 3,leveled as serious contamination.(4) Integrated pollution index of tomatoes and radishes was greater than 3,indicating that tomatoes and other crops have been subjected to heavy metal pollution,order of integrated pollution index descended as carrot,tomato and sweet potato.Carrot,the most polluted crops,appeared strong accumulation ability of Cd,Cu and Pb.(5) Heavy metal enrichment factor for three kinds of grown-well plants was greater than 1,indicating that the plants were capable to enrich these heavy metals,however,different plant species showed different capacity to the same element,and one kind of plants appeared different enrichment capacity to the same element. Accumulation ability of the plants descended as buddleja fallowiana, marestail,Artemisia subdigitata.For having been polluted by heavy metal,soil in these areas was improper to grow crops,and planting buddleja fallowiana,marestail, Artemisia subdigitata was good for pollution alleviation. Contamination in the soil and plants was mainly caused by deposits singularity and railings dumping irrationality of the mines,what's more,predatory exploitation to them resulted in not only resources waste,but also accelerating heavy metal pollution to our environment.