锑矿区土壤重金属污染及优势植物对重金属的富集特征

Heavy metal pollution in soils and characteristics of heavy metal accumulation of dominant plants in antimony mining area

通过野外调查采样,分析了冷水江锑矿区4个采样点土壤和优势植物中重金属含量,以及矿区生长的5种优势植物对Sb、As、Cd、Pb、Cu和Zn的的吸收与富集能力及其富集特性。结果表明,矿区土壤中6种重金属元素的平均含量均超出湖南省土壤背景值和全国土壤背景值,土壤受Sb污染最严重,其次是Cd、As的污染。5种优势植物淡竹叶、苎麻、芒草、狗尾草和白背叶体内Sb、As的含量都超过正常范围,具有修复矿区土壤Sb、As污染的潜力。其中苎麻对Sb的富集系数和转运系数均大于1,满足Sb超富集植物的基本特征,可作为生态恢复的先锋植物;芒草对Cd的富集系数和转运系数都大于1,对重金属有较强的耐性,作为重金属污染的修复植物具有较好的应用前景。

A study was conducted to investigate heavy metal contents in dominant plant species and their associated soils in antimony mine of Lengshuijiang.Contents of heavy metals such as Sb、As、Cd、Pb、Cu and Zn were determined in 5 dominant plant species in order to assess their potentials in phytoremediation of heavy metal polluted areas.The results revealed that all the average contents of the six heavy metals in soils of the mining area had exceeded the background value of heavy metals in Hunan Province and China.The soil of this mine was seriously polluted by Sb and Cd,as well as As.The Sb and As concentrations in the Lophatherum gracile,Boehmeria nivea,Miscanthus sinensis,Setaria viridis and Mallotus apelta exceeded the normal ranges,indicating their potentials in in-situ remediation of the heavy-metal contaminated soils.Among the studied plant species,both the bio-accumulating coefficient(BAC) and the biological transfer coefficient(BTC) of Boehmeria nivea were greater than 1,and this species can be designated as hyperaccumulator.It can be used as pioneer plants for revegetation of contaminated soil in mining area.In addition,Miscanthus sinensis could concentrate different heavy metals and both BAC and BTC of its were over 1 for Cd,which had a better potential and practical use in phytoremediation.