类芦植被对煤矸石堆场特征金属的富集特征及生物有效性的影响

以贵阳市花溪区麦坪乡废弃煤矿矸石堆场为研究区域,选择经过长期自然恢复定居于煤矸石堆场上的类芦植被为研究对象,研究类芦植被参与对煤矸石中特征金属(Fe、Mn、Cu、Zn)的富集特征、空间分布以及生物有效性的影响。结果表明:类芦植被参与下,煤矸石堆场特征金属在空间上主要分布在根系层和表层,且类芦地上部分对Mn和Fe、Cu、Zn的富集系数分别大于(比值1)和小于地下部分(比值1),类芦各部位金属含量的检测结果表明,Mn和Fe、Cu、Zn被类芦吸收后分别储存于地上部分(茎叶)和地下部分(根部)。类芦植被对Mn(3.62)和Fe(0.32)、Cu(0.60)、Zn(0.93)的转运系数分别大于1和小于1。相关分析结果表明,类芦植被对煤矸石特征金属的富集量与金属的有效态含量、全量之间呈显著或极显著正相关。除类芦根系层Mn的生物有效性高于对照外,类芦植被的存在能够明显降低煤矸石中特征金属的生物有效性,并对煤矸石中Mn、Zn具有较大转运、富集能力,因此可选择类芦作为煤矸石堆场污染物释放的原位生态控制和生态修复的先锋植物或优势植物。

The Effects of Neyraudia Reynaudiana Vegetation on Heavy Metal Enrichment Characteristics and Biological Effectiveness on Coal Gangue Dumps

An abandoned mine coal yard located in the Maiping township of Huaxi district,Guiyang City was selected as the study area,and Neyraudia reynaudiana vegetation settled on coal gangue dumps after long-term natural restore was selected as the research object to study the effect of the vegetation on the characteristics of metal (Fe,Mn,Cu and Zn) enrichment and spatial distribution and biological effectiveness of coal gangue. Results show that the characteristics of metal for the coal gangue dumps are mainly distributed in root and surface layer on the space under the vegetation participate in the process. And it''s aerial part of enrichment coefficient (for Mn, Fe, Cu, and Zn) is greater (the ratio for Mn > 1) or less than (the ratio for Fe, Cu and Zn<1) the underground part, respectively. The test results of metals for all parts of the plant show that these metals were absorbed and stored in the stem leaf part (Mn) and root (Fe, Cu and Zn) by the vegetation,respectively. The transfer coefficient is higher (for Mn, 3.62) and lower (for Fe, 0.32; Cu, 0.60; and Zn, 0.93) than 1, respectively. The correlation coefficient among the amounts of heavy metals in the plant, effective state content and total amount of metal are significant or extremely significant positive correlated. The exist of vegetation can obviously reduce biological effectiveness of coal gangue characteristics of metal (except for the biological effectiveness of root layer of Mn is higher than control). Given that the root of Neyraudia reynaudiana has greater transport capacity and concentration for Mn and zinc, so we can choose the vegetation as pioneer or advantage plants for ecological control and restoration to coal gangue dumps pollutants release in situ.