铅锌矿区土壤重金属含量及木本植物吸收特征

Heavy Metal Concentrations in Soils and Woody Plants Absorption Characteristics around Lead/Zinc Mineland

调查了湘西李梅铅锌矿区废弃地植物,分析了矿区植被物种组成、土壤和优势植物体内重金属含量,为铅锌矿废弃地植被恢复和重金属污染土壤的植物修复提供理论依据。结果表明,李梅铅锌矿区的高等植物共有20种,隶属12科,19属,且优势种全为木本植物,含灌木（或小乔木）、乔木、木质藤本植物;土壤重金属主要是Zn、Pb、Cd污染,且均超过国家土壤环境质量三级标准（GB 15618-1995）,超标倍数分别达2.74~16.65、1.08~7.08、31.17~118.43倍,污染严重;6种优势植物除马桑（Coriaria nepalensis Wall）植物体内Zn、Pb、Cd含量较低,为Zn、Pb、Cd的规避型植物外,木蓝（Indigofera tinctoria L.）、盐肤木（Rhus chinensis Mill.）、构树[Broussonetia papyrifera（Linnaeus）L＇Heritier ex Ventenat]、地果（Ficus tikoua Bur.）、两面针[Zanthoxylum nitidum（Roxb.）DC.]均表现对Zn、Pb、Cd具有一定的吸收,其中,两面针对Cd的吸收富集能力较强,为Cd富集型植物。

The plants species composition and growth status were surveyed and heavy metal contents in soil and dominant plants of Limei lead / zinc mineland, Xiangxi were analyzed. The results showed that there were 20 species plants belonging to19 genera in 12 families, and the dominant species were woody plants,in which including shrubs, small trees, trees and woodiness lianas. Soil Zn, Pb and Cd pollution were serious, which contents more than national standards for environment quality of grade three soil（GB 15618-1995）, with excessive ratio of 2.74~16.65,1.08~7.08,31.17~118.43 times,respectively.Six dominant plants, Indigofera tinctoria L., Rhus chinensis Mill., Broussonetia papyrifera（Linnaeus） L＇Heritier ex Ventenat,Ficus tikoua Bur., and Zanthoxylum nitidum（Roxb.） DC. absorbed a large amount of Zn, Pb, and Cd by the roots and transported to the shoots, especial Zanthoxylum nitidum（Roxb.） DC. which absorbed larger Cd than the others, and could be used to clean up the soils containing light to moderate toxic metal concentration and with high-value, which could be Cd accumulator. While, Coriaria nepalensis Wall. absorbed less Zn, Pb, and Cd than the other five plants, could be Zn, Pb and Cd excluder.