针对大气沉降对茶叶重金属积累的影响,选择了2个有明显污染源(分别受交通污染和工业污染影响)和1个无明显污染源(主要受大气循环物质沉降的影响)的3个茶园,采用覆膜和露天对比研究了茶叶中重金属Pb、Cd和Cr的积累状况。结果表明,试验期间大气沉降对茶树新叶的重金属积累影响较大,对老叶中重金属积累的影响较小;交通污染对茶叶Pb和Cd积累有明显的影响,工业污染对茶叶Pb、Cd和Cr积累有明显的影响,影响程度随距离公路或工厂距离的增加而下降;无明显污染源区大气沉降对茶叶Pb积累也有一定的影响,随海拔高度增加而下降。覆膜后,交通污染区新叶中Pb和Cd和Cr积累分别降低了27%-46%、21%-36%和13%-33%;工业污染区新叶中Pb、Cd和Cr积累分别降低了22%-44%、23%-32%和24%-29%;而无明显污染源区新叶中Pb含量下降了13%-19%。结果认为,大气沉降是茶叶重金属的重要来源之一,控制茶区大气污染和避免在大气污染区种植茶叶对减免茶叶重金属积累有重要作用。

Experiments were carried out to test the effects of atmospheric deposition on the heavy metal accumulation in tea leaves. The experiments concern three sites with different pollution sources of atmospheric deposition, including traffic pollution, industrial pollution and non-point pollution areas, and are under the conditions of open air and plastic film cover. The results show that the atmospheric deposition has a notable effect on the heavy metal accumulation in young tea leaves, but not for old tea leaves. The traffic pollution increases significantly the accumulation of Pb and Cd in young tea leaves. The industrial pollution increases significantly the accumulation of Pb, Cd, and Cr in young tea leaves, with its effect being decreased with the increase of the distance from a highway or factory. The altitude also affects the accumulation of Pb in the young tea leaves in the non-point pollution area. As compared with these, the accumulation of Pb, Cd and Cr in young tea leaves under plastic film cover conditions is decreased by 27%-46%, 21%-36% and 13%-33% for traffic pollution area, and 22%-44%, 23%-32%, and 24%-29% for industrial pollution area. The accumulation of Pb in young tea leaves under plastic film cover conditions in the non-point pollution area is 13%-19% lower than those under the open air condition. The contribution of atmospheric deposition to the accumulation of heavy metals in tea leaves is greater in industrial pollution areas than in traffic pollution areas. It is very important to control the atmospheric pollution in the tea production area and not to plant teas in the area with heavy atmospheric pollutions.