Spatial variability and transfer of heavy metal soil-crop system in Tanglangchuang river in Yunnan province

The pollution of heavy metal in soil is related to the security of farmland ecosystem and crop.The polluted degree and the migration regularity of heavy metal elements,including Cd,Cr,Pb,Cu,Zn in farmland-crop system in TangLangChuan River watershed,were investigated.The results showed that the coefficient of variation for the containments of Cu and Cd in the soil Tanglangchuanang River watershed are 0.55 and 0.68,respectively,which stood the strong degree of variation.The average Cd containment reached 4.27 mg/kg.Enriched coefficient of heavy metal by crops from soil were as follows: CrCd,ZnPb.And there were high correlations between the containments of Cd,Cr and Cu in rape or that of Cu in broad beans and the background values in soil.There existed significant correlations between Zn and Cd,Zn and Pb,Cr and Cu in soil as well.The concentration grades of five heavy metal Cd,Cr,Pb,Cu and Zn were related to the surrounding enterprises,which illustrated that heavy metal pollution of soil in Tanglangchuan River watershed was seriously affected by artificial disturbance.The conclusion was important to reasonable plan industrial area and reduced risk of soil pollution.