Accumulation Of Copper, Cadmium, And Zinc In Tobacco And Their Control Research

As early as the1950s, the British Royal Society of Medicine had proposed the idea that smoking is harmful to health, although everyone known it and made a lot of research on the tar and nicotine cigarettes, but not on heavy metals. Until the Ninth Asia Pacific Conference on Tobacco or Health, a research report of the International Tobacco Control Policy Evaluation Project (ITC) was released to point out that the heavy metals lead, arsenic and cadmium were detected in13brands of cigarette tobacco produced in China, compared with the production of cigarettes in Canada, the highest content out of more than three times. The message not only raised the public cigarette security concerns, but also caused research of heavy metals on tobacco. The heavy metals in cigarette mainly come from the tobacco growth period and the cigarette manufacturing process. The second process impacts rarely on heavy metals. This thesis was concerned about the accumulation of environmental heavy metals on tobacco leaf during the growing period. By Determining the content of heavy metal on tobacco of different periods or different parts, enrichment of heavy metals on ten sampling pointed tobacco in the whole growth period, the major environmental sources of heavy metals in tobacco leaves, the author could determine the enrichment patterns and their main environmental source of heavy metals in tobacco, propose measures in order to reduce heavy metals in tobacco.The results showed that:the content trends of Cu, Cd and Zn in tobacco of various parts:Cu:upper leaves>tobacco stems>middle leaves>lower leaves> tobacco root; Cd: lower leaves>middle leaves>upper leaves>tobacco stems> tobacco root; Zn:upper leaves>middle leaves>lower leaves>tobacco stems> tobacco root. General trend was that a larger proportion of the heavy metal content in tobacco leaf, as a result of the main source of heavy metals in cigarette.The content trends of Cu, Cd and Zn in several growth periods were consistent. From seedlings in the greenhouses to the rosette stage, the heavy metal content was gradually increased by big variations; but to vigorous stage decreased, in the bud stage rose. the content of Cu, Zn increased slowly with changed a little, basically stable in Cd during the mature stage. The heavy metal content per unit mass overall trends grew up before and after baking. Common tobacco curing process impacted scarcely upon heavy metals, which could be neglected during the research of controlling heavy metals in tobacco.The heavy metal content of air and irrigation water was less in the tobacco base, which kept stabilized; while inversely proportional between variations changed of heavy metals in tobacco and soil indicating that the heavy metals basically came from the soil. During selecting the tobacco soil, you should choose the soil with lower background heavy metal.