WANG Yang;LI Baogang;ZHANG Mingkui
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.
