Abstract:

In the present study, the uptake and translocation characteristics of lead (Pb) in tea plants were explored via pot experiment and literature review. Based on the collected data in literatures, the regression model of Pb contents in soil and tea leaves was constructed. Based on the pollution source inventory method and census data, the Pb pollution risk of tea gardens in Zhejiang Province, China, was analyzed. It was shown that the Pb contents in tea plants increased with the elevated exogenous Pb addition. When the exogenous Pb addition amount reached 500 mg·kg^-1, the Pb content in new leaves of tea could be 22.83 mg·kg^-1. The Pb accumulation amount in tea plants increased as new leaves<old leaves<stem<root. Based on the collected data, when soil Pb content was below 100 mg·kg^-1, the Pb content in tea leaves could meet the requirement of national standard. But, when soil Pb content was higher than 150 mg·kg^-1, the Pb content in tea leaves would exceed the national standard. The Pb emission in Zhejiang exhibited spatial-temporal variation during 1990-2018. After a rapid growth in 2009-2014, the Pb emission was still relatively high. Efforts should be made to cut Pb emissions according to the local conditions. Based on the census data and the constructed model, it was predicted that the Pb pollution risk of tea in Zhejiang would be further increased under the current industrial mode. Thus, Pb pollution risk of tea production in Zhejiang should never be neglected.

Key words: lead pollution, tea, source identification, food safety