Lead Absorption and Accumulation in Houttuynia cordata Thunberg and Hygienic Safety Evaluation

摘要

The lead absorption and accumulation in Houttuynia cordata Thunb. and its Hygienic Safety was studied by field sampling and analysis. Results showed that Houttuynia cordata Thunb. has strong absorption ability of lead. In the samples collected, the maximum lead content in the leaf, stem and root respectively was 40.03, 11.05, 7.57 mg/kg in Houttuynia cordata Thunb., in which the content was higher in stem than in root, and the highest in leaf,. Not only the maximum content was consistent with this order but also the lead content was in all samples. As vegetable, the lead content in the leaf, stem and root of Houttuynia cordata Thunb. was higher than the limit standard maximum levels of contaminants in foods(GB2762-2005) in China. Only did the content of leaf exceed the limit standard the standard for herbal plants and praeparatum foreign economic trade(WM/T 2-2004) among traditional Chinese medicine in China. The ability of the absorption of lead by Houttuynia cordata Thunb. was affected by the lead content in soil and physical and chemical properties of soil, The lead content, total nitrogen, available potassium, and clay content in soil were associated with the lead content of root, which were in significant positive correlation with the available phosphorus, available nitrogen, and organic content, Whereas soil CEC and pH have negative correlation with it, and soil physical and chemical properties showed no significant influence on lead content of stem and leaf of Houttuynia cordata Thunb..