Factors Affecting The Uptake Of Fluoride From Soil Into Tea Leaves Of Jiangsu Province And Discussion Of Safety Level Of Tea Fluoride

As an essential microelement to human, a proper amount of fluoride has an active effect to skeleton and teeth. But drinking some tea of extremely high-content F for a long time may result in the over-intake of F. By field experiment and laboratory experiment, it discussed the current F status of tea products of countrywide, soil and tea F status and effecting factors of Jiangsu typical tea plant, the dissolve orderliness of water-soluble F during the process of simulating soil acidification experiment and F safety level of tea. On the basis of realizing the F status of our country, we want to seek effective measures to reduce tea F, controlling F content under the level of a hazard to human health; besides, F safety level of tea was discussed. The following is the summary of the results.The F content of 124 tea and 19 tea drinking samples of various provinces were investigated. The results showed that the range of F content of these tea were rather great, F content of some tea exceeded standard. F content of various breads, grades, areas had distinction. In general, tea F content status of Jiangsu was fine, only individual tea F content approached outside standard. Referring to our drinking water standard, about third tea drinking products measured up. Consulting the bottle-water and drinking standard of U.S.A, about 21.6% tea drinking products did not measure up.F content in different parts of tea plant was different. The distribution rule was as follows: old leaf>lateral stalk>young leaf>main stalk>main root>side root. Tealeaves had the characteristic of enriching F hardly; the F content of old leaves outclassed young leaves. F content of all old leaves exceeded both internal and external standards, very few young leaves exceeded external standard. Tea F content decreased with the increasing of soil pH, soil cation exchange capacity and the content of clay, and increased with the increasing of soil organic materials, but the decreasing or increasing trend was not notable. Soil water-soluble F content decreased with the increasing of soil pH and the content of clay, increased with the increasing of soil organic materials significantly, and decreased with the increasing of soil CEC, but not significantly.