摘要
为了解重金属元素在茶园土壤-茶叶-茶汤系统中的污染及转移特征,探讨茶园种植作为锰矿区恢复利用模式的适宜性,选取广西两茶园(桂林某知名茶园和广西锰矿区某茶园),分别采集土壤和茶树样品,并用茶叶泡制茶汤,对其中的Ca、Mg、Cu、Zn、Mn、Pb、Cd、Cr、Al含量用ICP-AES法进行测定,同时测定土壤的理化性质。结果表明,两茶园土壤缺乏N、P营养;矿区茶园土壤受重金属污染严重,除Mg和Cu外,其他重金属含量显著高于桂林茶园,其中矿区茶园土Cr和两茶园土Cd含量均超过土壤环境质量二级标准;Zn、Pb、Cd、Cr主要存于茶树的根、茎中,而Ca、Mg、Mn、Al主要存于茶叶中,Cu则在茶树中分布相对均匀;Ca、Mg、Cu、Zn、Mn、Al的溶出量随泡茶时间的延长而增加,Cd、Cr在茶汤中的溶出量非常小,随时间变化不大,嫩叶Pb溶出要比老叶慢;茶叶对Ca、Mn富集能力很强,对其他重金属元素富集能力相对较弱;由于土壤Cd、Cr超标,且Mn、Al通过茶叶富集后大量进入茶汤,可能威胁人类健康,茶园种植不适宜作为矿区废弃地早期的复垦模式。
Tea is the most popular drink around the world and its quality and safety concern human health directly. Extensive soil and tea tree samples were collected from two tea gardens（ a noted tea garden in Guilin and a mineland tea stand in Bayi Mn mine ）in Guangxi to assess the heavy metal contamination level and probe the metal transportation among tea garden soil-tea leaf-tea liquor system, and based on these, to evaluate the suitability of tea plantation as a restoration mode for Mn mineland. The concentrations of Ca, Mg, Cu, Zn, Mn, Pb, Cd, Cr and Al in garden soil, tea tree and tea liquor were determined by ICP-AES. Results showed that both the two tea gardens were short of nitrogen and phosphorus. Soil in the mineland tea stand was heavily contaminated by heavy metals. Except for Mg and Cu, concentrations of other seven metals in mineland tea stand were much higher than those in Guilin tea garden. Cr level in minelaud and Cd levels in both sites exceeded the prescribed values of Soil Quality Standard（ Grade Ⅱ ）. Zn, Pb, Cd and Cr were mainly stored in the tea root and stem, and Ca, Mg, Mn and Al in the tea leaf, while Cu was more evenly distributed within different tissues. Regarding the dissolving rate in tea-making process, Ca, Mg, Cu, Zn, Mn and Al levels in the tea liquor increased as the time progressed; however, Cd and Cr levels in the liquor were neglectable and remained relatively stable. Pb dissolving rate from tea buds was slower than that from mature leaves. Tea leaf had stronger bioaccumulation for Ca and Mn. Because Cd and Cr concentrations in the mineland tea stand exceeded the Soil Quality Standard （Grade Ⅱ, recommended for agricultural cultivation）, and the high Mn and Al levels in tea leaf might threaten human health through dissolving into the tea liquor, tea plantation was not suggested as a way to reclaim the Mn mineland at early restoration stage.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2008年第6期2151-2157,共7页
Journal of Agro-Environment Science
基金
国家自然科学基金(30560032)
广西科学研究与技术开发计划项目(桂科基0575047)
广西师范大学引进人才科研启动基金资助项目
关键词
茶园土壤
重金属
茶叶
茶汤
溶出率
生物富集系数
tea garden soil
heavy metal
tea leaf
tea liquor
dissolving rate
bioaecumulation factor
