Bio-effect Of Heavy Metals In Plants

The content of heavy metals(Pb,Cd,Cr,As.et) in vegetables (leek,celery ,radish and spinach.et) contaminated with a Lead-Zinc -Silver(Pb-Zn-Ag)mine in Qixia District in Nanjing were studied in this thesis. Total concentrations of Lead (Pb), Chromium (Cr), Copper (Cu) , Zinc (Zn) , Arsenic (As) and some other elements in vegetables were determined by inductively coupled plasma-mass spectrometry(ICP-MS).The assessment on heavy metal pollution and distribution of heavy metals in vegetables were systematically studied based on total concentrations. furthermore, the min-area distribution, subcelluar distribution and speciation of heavy metals in main vegetables were discussed based on using new technique. Main results are as follows:1. Most of vegetables studied has suffered from pollution of Pb,As,Cd,Cr and Zn, the exceeding standard rate of Pb and As are 91.7%, and Cd is less serioursly. The heavy metal pollution in leave-vegetables are more seriously than rootstalk.2. Among all these kinds of vegetables determined, shallot, garlic and leave-vegetables show the highest content of heavy metals, especially Pb, and bean vegetables the lowest. Besides, there is some tendency of distribution for heavy metals in different parts of one kind of vegetable, for example, the content of Pb, as well as As, in root is ten times as high as that in leaves of raphanus sativus.3. The absorbency of heavy metals differed in various vegetables. In the aspect of absorbtion of Pb, the order was leek>cabbage> spinach>raddish; the rank was cabbage> spinach> leek> raddish to the absorbtion of As; as to the absorbtion of Cd, spinach> cabbage>leek> raddish; the order changed into raddish>spinach> cabbage>leek and cabbage>spinach> leek>raddish in the absorbtion of Cr and Cu. In addition, the absorbency of heavy metals differed in elements.4. The min-area's distribution of heavy metal in main vegetable samples (such as radish) showed some trend according to intensity counts: in transverse section of radish, the intensity counts of Pb, As and Cr are more high in caulis and cuticle than in other part.5. The sub-celluar distribution of heavy metals were also different.The distribution of Pb and Cr was F1>F2>F3>F4. As to the distribution of Cd and As, the rule was F1> F4 >F2>F3 and F1> F2>F4>F3 respectively.6. The concentration of lead changed as the absorbtion peak of protein of leek. The molecular weight of the protein of leek, raddish and spinach was less than 10000 through forther research.