Eco geochemical characteristics of the Tieguanyin tea gardens in Fujian Province

Abstract: It has been identified that a high geochemical background of some heavy metals including Pb exists in the southeastern part of China. There is a potential eco?geochemical hazard risk from heavy metal mobilization caused by soil acidification due to acid precipitation and improper manure. The main production area of Tieguanyin tea was selected for this study. Surface and sub?surface soils as well as tea leaves were collected from totally 79 tea gardens. Heavy metals in soils and tea leaves, major elements and physicochemical indicators of soil samples were determined. It is found that Hg, Pb, Se and Zn in tea garden soils are higher than their geochemical backgrounds of national soils, and this is attributed mainly to soil?parent rocks controlled by geological setting. However, soil properties including particle composition, organic material content and pH also play important roles in trace element concentration. Some non?nutrition elements for vegetation including As, Cd, Cr, Hg, Se, Pb and F are accumulated in matured leaves compared with their values in sprouts. Nutritive elements such as Cu, Ni and Zn seem to accumulate in sprouts to meet the demand of tea growth. Although the relationships between soil and tea leaves are quite complicated for most elements, there exists obvious positive correlation between soils and tea leaves in Cr and Pb content. This discovery provides the mathematical basis for establishing a model for forecasting lead impact on ecosystem.