粤东铅锌尾矿三种优势植物对重金属的吸收和富集特性研究

Characteristics of absorption and accumulation of heavy metals for three dominant plants in Pb-Zn mine tailings eastern Guangdong

关键词:  种子铅锌尾矿  富集植物  重金属污染  植物修复  萌发  休眠  喀斯特地貌

Key words:  Pb-Zn mine tailings  hyperaccumulator  heavy metal contamination  phytoremediation

摘要:

为探讨铅锌矿废弃地优势植物在重金属污染土壤植物修复中的应用潜力,利用野外采样分析法,从粤东梅县丙村铅锌尾矿区采集其三种优势植物类芦、黄荆、盐肤木的根、茎、叶和土壤样品,测定和分析Pb、Zn、Cu、Cd四种重金属含量。结果表明:该矿区土壤污染严重,Pb、Zn、Cd含量远超土壤环境质量的三级标准,Cu超出二级标准; 根际土壤和非根际土壤重金属含量均为Pb>Zn>Cu>Cd,但根际土壤的重金属含量显著低于非根际土壤; 这三种植物对Pb、Zn、Cu的转移系数大于1.0,对Cu的富集系数最高,Pb最小,但对四种重金属的富集系数均小于1.0,均未达到超富集植物临界含量标准。三种植物为该矿区的优势植物,说明它们对土壤的重金属污染有很强的耐性,虽然并非典型的超富集植物,但对污染土壤仍有较好的修复效果。

Abstract:

The root,stem,leave samples of three dominant plants,Neyraudia reynaudiana,Vitex negundo,Rhus chinensis,and soil samples were collected from Bingcun Pb-Zn mine tailings in Meixian County,Eastern Guangdong. The contents of Pb,Zn,Cu,Cd were then measured and analyzed comparatively. The results were as followed:the soil pollution in this wasteland was serious,the Pb,Zn and Cd contents were far more than the environmental quality standard for Grade Ⅲ,Cu content also exceeded the standard for Grade Ⅱ. The descending order of heavy metals in non-rhizosphere soil and rhizosphere soil was both Pb>Zn>Cu>Cd,but the heavy metal contents in rhizosphere soil were significantly lower than that in the non-rhizosphere soil. The transfer coefficients of three plants for Pb,Zn,Cu were greater than 1.0,and the enrichment factor of Cu was the highest,while Pb was the minimum,but the enrichment factors of four heavy metals were all less than 1.0,so these three plants did not meet the standards of critical content of hyperaccumulators. These three plants were the dominant plants in this wasteland,indicating that they had a strong tolerance to the heavy metal pollution in the soil,although they were not typical hyperaccumulator,but there was still good effect on remedying contaminated soil.