Matakala Nalukui, Chirwa Paxie W, Mwamba Theodore M, Syampungani Stephen
Department of Plant and Soil Sciences, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria 0022, South Africa.
Oliver R. Tambo Africa Research Chair Initiative (ORTARChI) Chair of Environment and Development, School of Natural Resources, The Copperbelt University, P.O. Box 21692, Kitwe, Zambia.
Heliyon. 2023 Feb 10;9(3):e13585. doi: 10.1016/j.heliyon.2023.e13585. eCollection 2023 Mar.
Mining activities are among the key sources of soil metal contamination in the Zambian Copperbelt, resulting in drastic landscape transformation. Plant species growing naturally on mine wastelands represent an asset for remediation on the disturbed ecosystems in the region. However, little is known about the suitability of Zambian native tree and shrub species for phytoremediation. The current study was carried to determine tree species richness and abundance on seven mine wastelands across the Zambian Copperbelt and evaluate their phytoremediation potential. Field inventory and post-hoc ecological analyses allowed identification of 32 native tree species, belonging to 13 different families, of which Fabaceae (34%) and Combretaceae (19%) predominated. Most of the identified tree species were found to be Cu, Co, Cr, Ni and Mo excluders. Among them, (Anacardiaceae), (Myrtaceae), (Fabaceae) and (Moraceae) were revealed as the most dominant tree species across the studied tailing dams (TDs) making them ideal candidates for metal phytostabilization. And coincidentally, their richness was positively correlated with high soil Cu concentration, a sought-after trait for phytoremediation of heavily polluted environment. Intriguingly, most identified tree species proved not suited for phytostabilization of Mn, Zn, B and Ba. On the other hand, species such as , , actively translocated these metals to leaves (TF > 1), indicating their potential for phytoextraction of Cu, Co, Cr, Ni, and Mo notably. Species richness and abundance significantly varied across the seven studied TDs. This was however barely influenced by soil metal contents, suggesting additional drivers dictating tree species-environment relationship in the context of studied TDs. The findings of this study provide crucial information in prospect of tree-based ecological restoration of mine wastelands, having revealed a diversified floristic composition of wastelands-native trees in the region, and clarified their respective phytoremediation attributes.
采矿活动是赞比亚铜带土壤金属污染的主要来源之一，导致了剧烈的景观转变。生长在矿场荒地上的植物物种是该地区受干扰生态系统修复的一项资产。然而，对于赞比亚本土树木和灌木物种在植物修复方面的适用性知之甚少。当前的研究旨在确定赞比亚铜带七个矿场荒地上的树种丰富度和丰度，并评估它们的植物修复潜力。实地调查和事后生态分析确定了32种本土树种，分属于13个不同的科，其中豆科（34%）和使君子科（19%）占主导。大多数已确定的树种被发现是铜、钴、铬、镍和钼的排斥者。其中，漆树科的、桃金娘科的、豆科的和桑科的被揭示为在所研究的尾矿坝中最主要的树种，使其成为金属植物稳定化的理想候选者。巧合的是，它们的丰富度与高土壤铜浓度呈正相关，这是重度污染环境植物修复所追求的特性。有趣的是，大多数已确定的树种被证明不适合对锰、锌、硼和钡进行植物稳定化。另一方面，诸如、、等物种将这些金属积极转运到叶片中（转运系数>1），表明它们在植物提取铜、钴、铬、镍和钼方面具有潜力。在七个研究的尾矿坝中，物种丰富度和丰度有显著差异。然而，这几乎不受土壤金属含量的影响，这表明在研究的尾矿坝背景下，还有其他驱动因素决定着树种与环境的关系。这项研究的结果为基于树木的矿场荒地生态恢复提供了关键信息，揭示了该地区荒地本土树木多样化的植物组成，并阐明了它们各自的植物修复属性。
