茶叶稀土含量对植物性食品质量安全的影响

Effect of rare earth content on the quality and safety of plant food

稀土元素(rare earth,简称RE)为重金属元素,具有广谱的生物毒性并可产生低剂量蓄积效应,农产品中稀土元素的安全问题越来越受到人们的重视。鉴于茶叶因稀土元素含量超标而引发诸多争议与质疑,本文结合研究结果与文献调研,得出以下结论:1基于稀土元素的低剂量效应,茶叶的稀土元素持续摄入及其在体内的蓄积对健康存在的潜在影响应予以重视;2制定植物性食品稀土元素相关限量标准具有必要性、科学性、前瞻性,以保障农产食品的质量安全;3茶叶的稀土元素含量超标的主因是人为持续使用含稀土元素的肥料,特别是含稀土元素的叶面肥,茶叶的稀土元素高残留与稀土元素的土壤累积效应、茶树(叶)的生物学特性与对稀土元素的高度选择性吸收等有关,茶叶中源自土壤的稀土元素应是土壤固有的和外源稀土元素累积于土壤中叠加的,农用稀土元素产品的性质与农业惯用的植物生长调节剂的特性要求相违背,将其用于茶叶的举措是导致茶叶稀土元素含量升高或超标的主要原因;4解决茶叶稀土元素含量升高或超标的关键措施是倡导茶叶生产中杜绝使用稀土元素肥料,从源头切断茶叶稀土元素的来源,减轻土壤和茶树(叶)的稀土元素承载。

Rare earth is heavy metal element,with broad-spectrum biological toxicity and low dose accumulation poison effect.The quality issue of rare earth in agricultural products has received much attention,lately.There is a lot of discussions and controversies on the high content of rare earth in tea.Basing on the results of published literature,this paper mainly focuses on the following issues：（1）The effect of constant rare earth intake from tea on human health and its accumulation in human body.（2）It is necessary to set standard on the use of rare earth in agricultural products,that is＇ limit on the use of rare earth in plant food（GB 13107-1991）.This is not only the need of international liability,but also the request to guarantee the safely of agricultural products.（3）The main reason of high rare earth content in tea is the use of rare earth fertilizer,especially rare earth leaf fertilizer.Tee tree can highly selectively absorb rare earth and convert it to its own component due to its special biological characteristics.This may account for the high content of rare earth in tea and soil.The content of rare earth in tea is the combination of the innate and exogenous rare earth in the soil.Secondly,there is a huge difference between rare earth products and plant growth regulator.It is a big mistake to use rare earth products on agricultural products.（4）The key to solve the high content of rare earth in tea is to completely eradicate the use of rare earth fertilizer in tea production.It is good for both the soil and tee tree to cut off the source of rare earth.