Study Of Effects On Heavy Metals Of Excrement And The Soil

With the three scale pig farms in Nanchang suburb(each located at Youlan town, Shengmi town and Houtian village) as the research object, experiments has been done to measure heavy metal content (Cu,Zn,Mn,Ni,Gr,Cd and Pb) based on the system of Pannage, Pig excrement, Soil, Vegetables. Excel and SPSS and other software have been used for drawing charts and data analysis to analysis and discuss the related relationship between Pannage-Pig excrement, Pig excrement-Soil and Soil-Vegetables, investigate the heavy metal absorption situation of edible parts and inedible parts in vegetable and the content situation of all kinds of heavy metal in shallow soil and 20-40cm depth of soil. The evaluation of pollution situation has been done according to related standard.(1)Heavy metal analysis result in pannage is shown that for each sample points, the heavy metal content exceeded in around half of pannage. It happens obviously in cub-pig fodder. It is possibly because pigs need lots of nutrient element in growing period.(2) Heavy metal analysis result in Pig excrement is shown that there is certain correlation between heavy metal content in pig excrement and heavy metal content in corresponding pig fodder, Cu-Cu,Zn-Zn,Mn-Mn,Ni-Ni,Cr-Cr,Cd-Cd and Pb-Pb, which have obviously discrepancy in Cu-Cu and Zn-Zn.(3) Heavy metal analysis result in soil is shown that 2#pig farm has been polluted worst. The contents of Cu,Mn,Cr,Cd and Pb in soil are maximum among the three pig farm. Comprehensive pollution index show that around 1/3 vegetable root soil are in safety, clean, slight pollution grade and the other 2/3 soil are in middle and heavy pollution grade.(4) Heavy metal analysis result in vegetable is shown that the highest content of vegetable heavy metal is Zn,Mn and Cu in turn, the content of Ni,Cr,Cd and Pb are similar and lower. The different parts of the same vegetable have different heavy metal contents, and it is also different with correlation of the total connection of heavy metals and available heavy metals content in this vegetable root soil, each is shown as obviously discrepancy, normal obviously discrepancy and normal correlation.(5) In the average content of each heavy metal form of 20-40cm depth soil, only Mn's mainly combined form is Fe-Mn oxide. Cu,Zn,Ni,Gr,Cd and Pb's mainly combined forms are all residual state. Mn has the most potential hazardous, Cu,Cr and Pb are followed, Zn's potential hazardous is least. The potential hazardous of seven kinds of heavy metal element in Fe-Mn oxide combined form are largest, the potential hazardous of carbonate combined form is least. Comparing with shallow soil, the content of Zn,Cd and Pb in 20-40cm depth soil is a little higher, but the content of Cu,Mn,Ni and Cr in shallow soil is obviously higher.