某轻稀土尾矿库土壤铀、钍污染特征及植物筛选

Pollution Characteristics of U and Th in Soil and Plant Screening in Light Rare Earth Tailings

该研究选择中国北方某轻稀土尾矿库围墙外100 m范围内土壤和植物中铀、钍核素的含量为研究对象,采用野外采样、电感耦合等离子体质谱仪分析、单因子污染指数、富集系数、转运系数、根滞留系数等方法,分析计算该区域5种优势植物(紫花苜蓿Medicago sativa、盐地碱蓬Suaeda salsa、芦苇Phragmites communis、大籽蒿Artemisia sieversiana、波斯菊Cosmos bipinnata)并筛选铀、钍核素的富集植物。结果表明:优势植物铀核素的富集系数为0.01~0.03,转运系数为0.07~0.22,根滞留系数为0.78~0.93。优势植物钍核素的富集系数为0.01~0.08,转运系数为0.03~0.33,根滞留系数为0.67~0.97。该区域5种优势植物富集、转运能力钍核素强于铀核素;富集系数、转运系数均小于1,不是该污染物质的富集植物,不能直接利用当地植物进行土壤铀和钍核素修复,应引种乡土富集植物进行土壤污染修复。

In this study,five dominant plants(Medicago sativa,salt)were analyzed and calculated by field sampling,ICP-MS analysis,single factor pollution index,enrichment coefficient,transport coefficient,root retention coefficient,etc.Suaeda salsa,Phragmites communis,Artemisia sieversiana and Cosmos bipinnata were used to screen enrichment plants of uranium and thorium.The results showed that the enrichment coefficient,transport coefficient and root retention coefficient of uranium nuclides were 0.01~0.03,0.07~0.22 and 0.78~0.93 respectively.The enrichment coefficient of thorium nuclides in dominant plants is 0.01~0.08,the transport coefficient is 0.03~0.33,and the root retention coefficient is 0.67~0.97.The enrichment and transport capacity of the five dominant plants in this area is stronger than that of the uranium nuclide.The enrichment coefficient and transport coefficient are all less than 1.They are not the enrichment plants of this pollutant,so they can not be directly used for the remediation of soil uranium and thorium nuclide.They should be introduced to the local enrichment plants for remediation of soil pollution.