Effect Of The Heavy Metal Form In Soil And Zinc On Absorption And Distribution Of Heavy Metal In Tobacco

The essay systematically researched the forms and content of arsenic(As) mercury (Hg)、lead(Pb) and cadmium (Cd) in5types of soil and its influence on content of As、H、Pb、Cd in tobacco; And it tested the antagonism effec of different concentration of zinc sulfate on the accumulation of As、Hg、Pb、Cd in tobacco, analysed the distribution of As、Pb、Cd in tobacco about3types of soil. Thus we acquired a certain value of research results:1. The results show that, pH value and the total content of As、Pb、Cd in five types soil have significant difference, the total content of Hg have large difference; among them the total content of As in paddy soil is highest, with an average of40.10mg/kg; purple soil is minimum, average is3.967mg/kg; the total content of Hg in paddy field purple soil is highest, with an average of2.927mg/kg, the total content of As in upland land purple soil is minimum, average is just3.927mg/kg. the total content of Pb (12.65mg/kg)、Cd (0.42mg/kg) in paddy field red soil is highest, the total content of Cd in upland land red soil and paddy field purple soil is minimum,the average is separately0.14mg/kg and0.16mg/kg.2. Among different types of soil, the ratio of the residual-As、Hg、Pb、Cd is highest, they are all accounts for over50%of the total content; the exchangeable-As、 Hg、Pb、Cd is minimum, they just accounts for about0.01%-5%. The ratio of available As in upland red soil is higher than that in paddy field red soil, it in upland purple soil is lower than that in paddy field purple soil; The ratio of available Hg is highest on total Hg content in purple soil, they separately get27.935%and30.66%, the upland red soil is minimum, just is17.017%, but its ratio of exchangeable-Hg is highest, it get0.384%. The ratio of available Pb is lowest on total Pb content in upland purple soil, it is18.84%; Compared the paddy soil with dry land soil, the ratio of available Pb is higher on total Pb content in paddy field purple and red soil than in dry land soil. The ratio of available Cd is highest on total Cd content in dry land red soil, it gets35.34%, the dry land purple soil is minimum, it gets24.52%.3. In the tobacco of different types of soil, the content of As (0.416mg/kg)、Hg (0.198mg/kg)、Cd(1.15mg/kg) in upland red soil is highest, the tobacco content of Pb (1.51mg/kg) in paddy field red soil is highest. The content of As in upland purple soil is lowest, it gets0.189mg/kg. Pb(0.129mg/kg) in paddy field is lowest, and Cd in upland purple soil and paddy field soil is lowest, they are separately0.22mg/kg and0.23mg/kg. The total content of As、Kg、Pb、Cd in soil is high, it doesn’t mean the tobacco content is also high, but it is more easier to accumulate the heavy metal that plant tobacco in upland red soil.4. The essay research the effect of zinc on tobacoo absorbing As、Hg、Pb、Cd, the result show that, the accumulation of Cd in tobacco decreased after the concentration of zinc sulfate arrive at3g/L; at the same time, antagonism effect is enhanced with the concentration increased and it has no influence on the production and quality of tobacco; But when the concentration exceed6g/L, it will happen inhibition for the growth of tobacco plants,even cause zinc poisoning. Adding zinc sulfate has no too big effect on tobacco plants absorbing As、Pb.5. The research of the pot experiment for adding As、Hg、Pb、Cd shows that, there are significant differences in the adsorption of tobacco to the As、Pb in different types of soils, among the results, all the As、Pb adsorption is the highest to each parts of the tobacco in red soil, The trend of As、Pb’s distribution in the tobacco is root> lower leaves> middle leaves> upper leaves> stems, but the trend of Cd’s distribution in the tobacco is lower leaves> middle leaves> upper leaves> stems> root.