铅锌矿区土壤重金属污染与优势植物累积特征

Heavy Metal Pollution in Soils and Plant Accumulation in a Restored Lead-Zinc Mineland in Guangxi,South China

调查了广西泗顶铅锌矿废弃地土壤和植被,共记录到高等植物13科22种,按照YS/T461-2003方法分析矿区土壤中重金属含量,按照GB/T 15337-1994方法对植物样品进行前处理,采用PE-AA700型火焰原子吸收光谱仪分析了16种优势植物中重金属含量.结果表明:土壤已受到Pb,Zn的严重污染,冶炼厂所有植物的Pb,Zn含量都超过正常范围.蜈蚣蕨体内重金属含量最高,其地上部分能积累较高含量的Pb(w(Pb)=729.9×10-6),转移系数1.56,具备了超富集植物的某些特征.密蒙花叶片中能积累较高含量的Pb(w(Pb)=305.3×10-6),扩散和适应能力强.蜈蚣蕨和密蒙花可作为铅锌矿区生态恢复的先锋物种.复垦区主要经济作物重金属质量分数超过中国食品卫生标准,不宜食用.

In Siding lead-zinc mineland, 22 plant species from 13 families were found colonizing, some of which were planted agronomic ones. Minesoils and 16 types of dominant plants were analyzed using an atomic absorption spectrometer PE-AA700 according to the standards of YS/T 461-2003 and GB/T 15337-1994. The results show that minesoils are basically polluted by Pb and Zn. In the vicinity of smelt factory, the contents of Pb and Zn in all the analyzed plants exceed the normal ranges. Pteris vuttata L. had a higher accumulation （Pb content of 729.9 × 10^-6）aboveground and a higher translocation （as reflected by Biological Transfer Coefficient of 1.56） for Pb, which shows that it tends to be a hyperaccumulator. Flos Buddlejae which had a far more biology quantity compared with herbage plants possesses powerful diffusivity and adaptability despite growing in the soil polluted seriously by Pb and Zn. Pteris vuttata L. and Flos Buddlejae can be used as pioneer plants for revegetation of lead-zinc mining wasteland. However, the vegetable and crops cultivated on the reclaimed mineland are not safe for human consumption.