Scale and causes of lead contamination in Chinese tea.
We investigated the scale and causes of Pb contamination in Chinese tea. Lead concentrations in 1,225 tea samples collected nationally between 1999 and 2001 varied from <0.2 to 97.9 mg kg(-1) dry weight (DW), with 32% of the samples exceeding the national maximum permissible concentration (MPC) of 2.0 mg kg(-1) DW and a significant difference between tea types. There was an increasing trend in tea Pb concentration from 1989 to 2000. Proximity to highway and surface dust contamination were found to cause elevated Pb concentrations in tea leaves. Furthermore, Pb concentration in tea leaves correlated significantly and positively with soil extractable Pb, and negatively with soil pH, suggesting that root uptake of Pb from soils also contributed to Pb accumulation in tea. Potential contributions to human Pb intake from drinking tea were small at the median or national MPC Pb values, but considerable at the highest concentration found in the study.
Key Laboratory of Tea Chemical Engineering, Ministry of Agriculture, Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 3100008, China.
Wen-Yan
WY
Han
Fang-Jie
FJ
Zhao
Yuan-Zhi
YZ
Shi
Li-Feng
LF
Ma
Jian-Yun
JY
Ruan
D000393:Air Pollutants / Q000032:analysis; D028241:Camellia sinensis / Q000737:chemistry*; D002681:China; D004781:Environmental Exposure / Q000009:adverse effects; D004784:Environmental Monitoring / Q000379:methods; D005506:Food Contamination / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D007854:Lead / Q000008:administration & dosage / Q000032:analysis* / Q000633:toxicity; D018515:Plant Leaves / Q000737:chemistry; D018517:Plant Roots / Q000737:chemistry; D012987:Soil / Q000032:analysis; D012989:Soil Pollutants / Q000032:analysis; D013662:Tea / Q000737:chemistry*; D013997:Time Factors; D001335:Vehicle Emissions / Q000009:adverse effects / Q000032:analysis
D000393:Air Pollutants; D012987:Soil; D012989:Soil Pollutants; D013662:Tea; D001335:Vehicle Emissions; D007854:Lead