铅锌冶炼厂土壤污染及重金属富集植物的研究

Studies on soil pollution around Pb-Zn smelting factory and heavy metals hyperaccumulators

对株洲市铅锌冶炼厂生产区进行了植被和土壤调查。结果表明,该厂土壤污染以镉铅锌(Cd、Pb、Zn)最为严重,尤其是重金属镉在土壤中含量超过背景值高达208倍,分析原因主要是由于大气尘降和雨水淋洗等使得污染加重。实验采集并分析测定了9种植物中重金属富集量,首次报道了土荆芥是一种铅超富集植物,其体内Pb质量分数高达3888 mg/kg。另一种植物商陆能大量富集镉,具有地下部向地上部转运能力强、生物量大、富集总量高的特点,有很大研究价值和应用潜力。另外,荨麻对Zn有较强富集能力,这3种植物可分别用于铅、镉和锌等3种重金属污染土壤的植物修复。

In this paper, soils and native vegetation in the vicinity of Zhuzhou Pb-Zn Smelting Factory were investigated. The results showed that the soil was severely contaminated with cadmium, lead and zinc (Cd, Pb and Zn). Especially, the Cd concentration in the soil was more than two hundredfold (208) of the background. Data analysis indicated that the atmospheric dusts originated from the factory and rain-drop scavenging were the important factors responsible for the severe heavy metals pollution problem in the soil. In addition, nine representative plants of the native vegetation were collected and analyzed for heavy metal concentrations. For the first time, we reported that C. ambrosioides was a hyperaccumulator of lead, and the in vivo concentration of Pb could reach as high as 3888 mg/kg. Also, it was found that Phytolacca acinosa had good capability to enrich Cd. Phytolacca acinosa displayed many good traits, such as excellent ability to transport Cd form roots to stems and leaves, bigger biomass and larger enrichment capacity. Thus, P. acinosa plant showed promising potentials in phytoremediation applications and was warranted for further studies. We also noted that another plant, Urtica fissa, seemed to exhibit excellent enriching power for Zn.In summary, our results indicated that these three plants could be used to effectively treat soils contaminated with heavy metals Cd, Pb and Zn.