滥木厂汞铊矿区土壤污染和优势植物富集重金属特征

Heavy metal contamination and accumulation in soil and dominant plants from Lanmuchang mercury-thallium mine area

为筛选出适合滥木厂汞铊矿区生态修复的植物,采用同位素稀释/电感耦合等离子体质谱(ID/ICP-MS)法分析了滥木厂汞铊矿区9种优势植物及根际土壤中的Mn、Ni、Cu、Zn、As、Pb、Cr、Cd、Hg和Tl含量,并采用富集因子(EF)、生物富集系数(BCF)和生物转运系数(BTF)评价了土壤重金属污染程度和植物对重金属的富集和转运能力。EF评价结果显示,根际土壤存在Hg和Tl极强富集,As强富集,Cu轻微富集,而Pb、Zn、Cr、Cd、Mn和Ni未富集。基于BCF和BTF的分析结果得出:芒萁(Dicranopteris dichotoma)是Mn、Zn和Cd的富集型植物,糙皮桦(Betula utilis)是Mn、Ni和Zn的富集型植物,桂皮紫萁(Osmundastrum cinnamomeum)是Mn、Cd和Tl的富集型植物,白茅(Imperate cylindrica)是Mn和Ni的富集型植物,蜈蚣草(Pteris vittata)是As的超富集型植物;糙皮桦是Cd的根部囤积型植物,芒萁是Ni的根部囤积型植物,桂皮紫萁是Ni和Zn的根部囤积型植物,白茅是Zn和Cd的根部囤积型植物,紫羊茅(Festuca rubra)是Mn、Zn和Cd的根部囤积型植物,五月艾(Aritemisia indica)是Cd和Tl的根部囤积型植物;芒草(Miscanthus sinensis)和千里光(Senecio scandens)是规避型植物。研究区土壤存在Tl-Hg-As复合污染,蜈蚣草可作为研究区As污染土壤的修复植物,桂皮紫萁可作为Tl污染土壤的修复植物;五月艾可作为Tl污染土壤的植物固化;芒草和千里光可用于研究区的植被修复。

In order to screen suitable plants for ecological environment remediation of heavy metal in Lanmuchang mercury-thallium mine area,the contents of Mn,Ni,Cu,Zn,As,Pb,Cr,Cd,Hg and Tl in the rhizophere soils and native dominant plants were determined by isotope dilution/inductively coupled plasma mass spectrometry(ID/ICP-MS).The heavy metal contaminations of the rhizophere soils,bioaccumulation and translocation of the heavy metals in plants were evaluated by enrichment factor(EF),bioconcentration factor(BCF)and biological translocation factor(BTF).EF evaluation results showed that the rhizosphere soils were extremely enriched by Hg and Tl,strongly enriched by As,slightly enriched by Cu,not enriched by Pb,Zn,Cr,Cd,Mn and Ni.Based on BCF and BTF,the following results were obtained:Dicranopteris dichotoma was Mn,Zn and Cd accumulator plant,Betula utilis was Mn,Ni and Zn accumulator plant,Osmundastrum cinnamomeum was Mn,Cd and Tl accumulator plant,Imperate cylindrica was Mn and Ni accumulator plant,and Pteris vittata was As hyperaccumulator plant;Betula utilis was Cd root-hoarding plant,Dicranopteris dichotoma was Ni root-hoarding plant,Osmundastrum cinnamomeum was Ni and Zn root-hoarding plant,Imperate cylindrica was Zn and Cd root-hoarding plant,Festuca rubra was Mn,Zn and Cd root-hoarding plant,and Aritemisia indica was Cd and Tl root-hoarding plant;Miscanthus sinensis and Senecio scandens were excluder plants.The soils of study area were in severe Tl-Hg-As combined contamination.Pteris vittata could be used as a remediation plant for As-contaminated soil in the study area,Osmundastrum cinnamomeum used as a remediation plant and Aritemisia indica used as a phytostabilization plant for Tl contaminated soil.Miscanthus sinensis and Senecio scandens could be used as vegetation restoration plant in the study area.