重新植被是大规模铝土矿残渣处置和管理的一种有前途的策略,通过根际过程可能影响潜在有毒元素(PTE)的地球化学稳定性。然而,铝土矿残留植被恢复过程中PTEs的地球化学行为和潜在机制尚不清楚。这项研究研究了在各种植被恢复策略下,铝土矿残渣-植被-渗滤液系统中PTEs的迁移和转化行为及其潜在机制,包括多年生黑麦草(黑麦草)和白三叶草(白三叶)的单种和共同种植,超过100天的微观实验。结果表明,pH值显著降低,EC,Na,Al,在各种植被恢复策略下,渗滤液中的Cr水平,随着铜的轻微增加,V,As,和Pb。随着时间的推移,pH值,EC,Na,Cr,Cu,V,Pb,随着渗滤液中的水平下降,而Al的那些,Fe,Mn,锌增加。平均pH值,EC,和钠的浓度,Al,Fe,再植被处理渗滤液中的Cr下降了6%-8%,21%-33%,2%-4%,19%-27%,7%-22%,15%-26%,分别,而Mn的平均浓度,V,Zn,增长了47%-134%,26%-46%,39%-47%,和3%-10%,分别,与未修正的治疗相比。与单一种植相比,共同种植通常对渗滤液成分的影响更大。Al的可用内容,Cr,铅下降81%-83%,57%-77%,55%-72%,分别,而重新植被的铝土矿残留物中其他PTE的含量增加。与单一种植相比,共同种植显着降低了PTE的可用性。除了Na和Mn,在各种植被恢复策略下,两种植被中PTEs的生物积累和运输因子均保持在1以下。铝土矿渣-植被-渗滤液系统中PTEs的迁移转化行为主要受pH和养分水平的影响。这些发现为铝土矿残渣重新植被过程中PTEs的迁移和转化行为提供了新的见解。
Revegetation is a promising strategy for large-scale bauxite residue disposal and management, potentially influencing the geochemical stability of potentially toxic elements (PTEs) through rhizosphere processes. However, the geochemical behaviors of PTEs and the underlying mechanisms during bauxite residue revegetation remain unclear. This study examined the migration and transformation behaviors of PTEs and their underlying mechanisms in the bauxite residue-vegetation-leachate system under various revegetation strategies, including single and co-planting of perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.), over a 100-day microcosm experiment. The results showed significant decreases in pH, EC, Na, Al, and Cr levels in the leachate under various revegetation strategies, with slight increases in Cu, V, As, and Pb. Over time, the pH, EC, Na, Cr, Cu, V, Pb, and As levels in the leachate decreased, while those of Al, Fe, Mn, and Zn increased. The mean pH, EC, and concentrations of Na, Al, Fe, and Cr in the leachate of the revegetated treatments decreased by 6%-8%, 21%-33%, 2%-4%, 19%-27%, 7%-22%, and 15%-26%, respectively, while the mean concentrations of Mn, V, Zn, and As increased by 47%-134%, 26%-46%, 39%-47%, and 3%-10%, respectively, compared to the unamended treatment. Co-planting generally exhibited a greater impact on leachate components compared to single planting. Available contents of Al, Cr, and Pb decreased by 81%-83%, 57%-77%, and 55%-72%, respectively, while those of other PTEs increased in the revegetated bauxite residue. Co-planting significantly reduced the availability of PTEs compared to single planting. Except for Na and Mn, the bioaccumulation and transportation factors of PTEs in both vegetation species remained below 1 under various revegetation strategies. The migration and transformation behaviors of PTEs in the bauxite residue-vegetation-leachate system were mainly influenced by pH and nutrient levels. These findings provide new insights into the migration and transformation behaviors of PTEs during bauxite residue revegetation.