了解安茶产区典型茶园土壤-茶树系统中重金属元素的富集能力以及在新、老叶间的含量分配和变化趋势，明确土壤-茶树系统中重金属元素的行为特征及其影响因素。

在安茶产区选取河岸洲地和低山缓坡2种典型茶园，按路距（距公路距离）和坡位分别设置3个采样带，采集土样和新、老叶样，利用微波消解法和ICP-MS测定样品中重金属元素Cr、Cu、Zn、As、Cd、Pb、Ni和Hg含量。

各样带土样中Cr、Cu、Zn、As、Cd、Pb、Ni和Hg元素平均含量均高于对应的叶样；Cu、Ni、Hg、Zn、Cr、Cd、Pb和As的平均富集系数依次减小，分别为0.420、0.330、0.310、0.180、0.060、0.040、0.010和0.004。除Cr、As和Hg外，洲地茶园中Cu、Zn、Cd、Pb和Ni的富集系数高于坡地茶园；除Hg外，坡地茶园老叶与新叶重金属元素的分配比一般大于洲地，茶树体内Cr、Cu、Hg、As和Pb由新叶到老叶以增加趋势为主，Cd则有减小趋势，而Zn和Ni以稳定趋势为主。

安茶产区典型茶园的土壤和叶片中重金属元素的含量均低于对应的国家限量标准；土壤-茶树系统中重金属元素具有低富集特征；新、老叶间重金属含量的变化趋势不确定；坡位和路距对土壤-茶树系统中重金属含量水平及富集系数的影响较为复杂。

From the perspective of ecological system theory, this study investigated the bioconcentration capacity of heavy metal elements in the soil-tea plant system of typical tea gardens in the An-tea producing areas. It also sought to determine the differences in heavy metal element content and its distribution between the new and old tea leaves. Finally, it identified the behavioral characteristics of the heavy metal elements in the soil-tea plant system in the An-tea producing areas, and the factors influencing them. This was conducted to trace the source of heavy metal contamination, and to devise strategies to prevent heavy metal pollution of tea products.

In the core area of An-tea production, Qimen County, Anhui Province, two types of landforms, riparian and gentle slope lands were selected as study sites. At the riparian sites, three sample belts were set at a spacing of 5 m, from near to far in terms of distance from the road. In the slope lands, three sample belts were set at 10 m height intervals from top to bottom, in areas characterized as highslopes, mesoslopes and lowslopes. Three sampling sites were set in each belt, and the natural grassland at the foot of the slope land tea gardens was selected as a control. At each site, soil samples were collected from within the 0—100 cm layer through stratification (with 20 cm between each sample) using the soil drilling method (φ= 6 cm; the soil depth of the high-slope sample belt being 60 cm). In addition, old and new tea leaves were collected randomly from around the sampling sites. The soil samples were air-dried, ground and sieved (1 mm), and the sample leaves were cleaned, deactivated and dried to a constant weight before being crushed and sieved (0.25 mm). Subsequently, and following microwave digestion, the contents of Cr, Cu, Zn, As, Cd, Pb, Ni and Hg were determined using ICP-MS, and the bioconcentration factor (B_f) and distribution ratio (D_r) of each heavy metal element in the soil-tea plant system was calculated.

The average Cr, Cu, Zn, As, Cd, Pb, Ni and Hg contents in the tea garden soil of the soil-tea plant system were all higher than those in the corresponding leaf samples. Similarly, the average Cr, Cu, As, Pb, Ni and Hg contents in the soil of the control grassland system were higher than those in the herbs, while the average Zn and Cd contents were lower than those in the herbs. The transfer and distribution of heavy metal elements in the soil-tea plant system and the grassland system were not consistent. Zn and Cd was concentrated to an extent in the herbs but this was not the case in the tea plants. The average B_f of Cu, Ni, Hg, Zn, Cr, Cd, Pb and As, which decreased successively, was 0.420, 0.330, 0.310, 0.180, 0.060, 0.040, 0.010 and 0.004, respectively. The B_f of the heavy metal elements in the riparian tea gardens were higher in the near and far sample belts, but lower in the middle sample belts. However, the B_fof the heavy metals in the slope tea gardens were higher in the highslope sample belts, and varied by elements in the mesoslope and lowslope sample belts. As for the two geomorphologic types, the B_f of Cu, Zn, Cd, Pb and Ni in riparian tea gardens were higher than those in the slope tea gardens. The D_rof all the heavy metal elements, except Hg, in the leaves from the slope tea gardens were generally greater than those from the riparian areas. In the tea plants, the Cr, Cu, Hg, As and Pb content was higher in the new leaves in comparison to the old leaves, while the Cd content was lower, and Zn and Ni remained stable. Topography only had a significant effect on the amount of As and Hg in the soil, while it had no significant effect on the Cr, Cu, Zn, Cd, Pb and Ni content in the soil, or the amount of all eight heavy metals in the new and old leaves. Slope position only had a significant effect on the Cu and Pb soil content, the amount of Hg in the new leaves, Zn in the old leaves, and the B_f of Hg in the old leaves. Distance from the road only had a significant effect on the Pb soil content and the B_f of Zn and Pb in the soil.

The average Cr, Cu, Zn, As, Cd, Pb, Ni and Hg contents in the soil of the soil-tea plant system of a typical tea garden in the An-tea producing area were all lower than those in the corresponding tea leaves. These heavy metals, which are found at low concentrations in the soil, contribute little to the concentrations in the tea leaves. There was no significant difference between the B_f of these heavy metal elements of the slope and riparian An-tea gardens. Furthermore, the distribution ratio of the elements, except Hg, in the leaves from the slope lands was `greater than those from the riparian gardens, although whether there are differences in the trends of the old and new leaves is unclear. Factors such as geomorphic type, plant age, slope position, and distance from the road all affected the behavior of the heavy metals in the soil-tea plant system. The average heavy metal content of the soil was lower than the risk control value, and the heavy metal content in the tea leaves was lower than the food contamination standard limit.