稀土尾矿库周边植物碱蓬对稀土元素的吸收与生物富集作用

Absorption and Accumulation of Rare Earth Elements by Suarez Salsa around the Rare Earth Tailings

为研究稀土尾矿库周边植物碱蓬对4种稀土元素(La、Ce、Pr、Nd)的吸收和富集特征,以广泛分布于稀土尾矿库周边的碱蓬及其根区土壤为研究对象,用ICP-MS法分析土壤中La、Ce、Pr、Nd、Sm、Gd的含量和碱蓬各器官中La、Ce、Pr、Nd的含量,并对土壤进行了污染评价。结果表明,土壤中6种稀土元素的平均含量顺序为:Ce>La>Nd>Pr>Sm>Gd,其数值分别为7826.9 mg/kg、4117.8 mg/kg、2251.0 mg/kg、1393.3 mg/kg、240.1 mg/kg、217.0 mg/kg,且稀土尾矿库周边土壤受到了严重的稀土元素复合污染;碱蓬对La、Ce、Pr、Nd的吸收没有特别的选择性;碱蓬对La、Ce、Pr、Nd的转移能力和耐受力较强,且碱蓬植物体内积累了较多的稀土元素,所以碱蓬在一定意义上可用于该地区稀土元素污染土壤的修复;在采样点GW-1~GW-11中,碱蓬各器官中La、Ce、Pr、Nd的含量水平为根>叶>茎;在采样点GW-12~GW-18中,碱蓬各器官中La、Ce、Pr、Nd的含量水平为根>茎>叶,即La、Ce、Pr、Nd主要分布于碱蓬根部;相关性分析表明,碱蓬各器官中的稀土元素大部分来源于其根区土壤;在采样点GW-1~GW-18中,碱蓬对La、Ce、Pr、Nd转移系数的平均值分别为0.976、1.013、0.897、0.944,说明稀土尾矿库周边的碱蓬对稀土元素的转移能力顺序为:Ce>La>Nd>Pr;碱蓬对La、Ce、Pr、Nd富集系数的平均值分别为0.117、0.153、0.108、0.149,说明稀土尾矿库周边的碱蓬对稀土元素富集能力顺序为:Ce>Nd>La>Pr。

The characteristics of absorption and accumulation for 4 kinds of rare earth elements(La,Ce,Pr,Nd)in the plant Suarez salsa around the rare earth tailings were studied,the Suarez salsa that widely distributed around the rare earth tailings and its root zone soils were selected as research objects,the contents of La,Ce,Pr,Nd,Sm and Gd in soil and the contents of La,Ce,Pr and Nd in various organs of Suarez salsa were analyzed by ICP-MS,and the soil was evaluated for contamination.The results show that:The order of the average content of the six rare earth elements in the soil is:Ce>La>Nd>Pr>Sm>Gd,with values of 7826.9,4117.8,2251.0,1393.3,240.1,217.0 mg/kg respectively,and the soil around the rare earth tailings is heavily polluted by rare earth elements;Suarez salsa has no special selectivity for absorption of La,Ce,Pr and Nd,has strong transfer ability and tolerance to La,Ce,Pr and Nd,and contains a large number of rare earth elements,therefore,Suarez salsa can be used to repair rare earth element contaminated soil in the region;In the sampling point GW-1~GW-11,the concentrations of La,Ce,Pr and Nd in various organs of Suarez salsa are in the order of root>leaf>stem;In the sampling point GW-12~GW-18,the concentrations of La,Ce,Pr and Nd in various organs of Suarez salsa are in the order of root>stem>leaf,that is,La,Ce,Pr and Nd are mainly distributed in the roots of Suarez salsa.The results of correlation analysis show that most of the rare earth elements in various organs of Suarez salsa are derived from the root zone soil;In the sampling point GW-1~GW-18,the average values of La,Ce,Pr and Nd translocation factor for Suarez salsa are 0.976,1.013,0.897,and 0.944,respectively,this indicates that the order of the transfer ability of Suarez salsa around the rare earth tailings to rare earth elements is Ce>La>Nd>Pr;The average values of La,Ce,Pr and Nd enrichment factors of Suarez salsa are 0.117,0.153,0.108,and 0.149,respectively,this indicates that the order of the enrichment ability of Suarez salsa around the rare earth tailings to rare earth elements is:Ce>Nd>La>Pr.