湘西铅锌矿区重金属污染评价及优势植物重金属累积特征

矿区土壤重金属污染在中国乃至全世界都是一个普遍的问题。采用现场采样、室内分析的方法,调查研究了湘西花垣铅锌矿区土壤及优势植物重金属含量,采用污染指数法和富集系数法对该矿区土壤和优势植物重金属含量进行了评价。结果表明,该矿区土壤主要受到Pb、Zn、Cd三种重金属污染。其中,Pb以轻-中度污染为主,Zn以中度污染为主,Cd以重污染为主。优势植物重金属含量测定表明,不同植物对重金属的吸收和累积特征不同,油茶属于金属富集型植物,毛萼莓、芒属于根部囤积型植物,飞龙掌血属于金属规避型植物。以上几种优势植物对重金属均具有一定的耐性,可以作为铅锌矿区弃地植物修复的优选物种。

Assessment of Heavy Metal Pollution in Mine Soil and Bioaccumlation Characteristics of Dominant Plants in a Lead-Zinc Mineland,West Hunan

Heavy metal pollution of a mineland is a widespread problem in the world,including China.Soils and dominant plants of seven species were sampled and determined in the Huayuan Pb-Zn mineland,Xiangxi.Pollution index and bioaccumulation factor were employed to assess heavy metal pollution.The results showed that the mine soils were characterized by elevated levels of Pb,Zn and Cd.Pollution index showed that the mine soil was seriously polluted by Cd,slightly to moderately polluted by Pb,moderately polluted by Zn,respectively.The main dominant plants could adapt to the unfavorable edaphic conditions of mine soil and were tolerant to heavy metals,but there were great variations in metal uptake and accumulation among different plant species,of which,Camellia oleifera belong to the accumulator plant whose roots could absorb a large amount of heavy metals and transported the metals to the shoots.Rubus tephrodes and Rubus chroosepalus had the typical characteristics of the root compartment which absorbed a large amount of heavy metals which were held in the roots.Toddalia asiatica,as an excluder plant,grew in the mine soil with elevated levels of heavy metals but absorbed less heavy metals than the accumulators.All these dominant plants can be used as preferential species of phytoremediation of lead-zinc mine wastelands.