Importance of Capping Material Properties in Remediation of Mine Tailings

摘要（项目5：Maier、Neilson、Babst-Kobrika、Rasmussen） 采矿场和冶炼厂附近的土壤受到微量元素污染， 人类和地球仪周围的环境。对尾矿进行植被重建， 通过风或地下水污染物（即植物修复）是一种有前途的“绿色”和低成本的干预措施 暴露在有毒物质中不幸的是，植物生长在大多数尾矿上受到抑制，使得有必要提供 用于种子发芽和幼苗生长的额外健康基质。目前的做法是安装 在植物播种之前，在尾矿上覆盖一个未受污染的土壤-砾石-岩石盖， 这种技术被称为“封顶和种植”。然而，关键的知识差距 关于植物-土壤相互作用的研究阻碍了这项技术的广泛和有效实施。的 该项目的主要目标是确定最佳战略， 危险的矿场。指导性假设是封盖材料的生物化学性质 是至关重要的发展强大的根系，可以传播到底层污染 尾矿该项目将采用创新的实验设计，制定具体的土壤健康指数 并评估覆盖材料深度和质量对根系构型的影响， 被称为滨藜（Atriplex lentiformis）的植物物种用于植物修复。各种封盖材料， 将在三个连续的温室研究中对储存的覆盖层和邻近的自然沉积物进行测试 汇集了先进的生态、基因组和土壤健康评估。具体来说，根系 将使用基于根管的非侵入性表型分析方法监测发育， 覆盖材料和来自美国西南部超级基金场地的尾矿的不同组合。 一旦确定了最佳土壤和植物参数， 将探索以具有成本效益的方式使用封盖材料。该项目将产生前所未有的机械 了解植物根系结构和功能对质量的响应的同时变化 尾矿修复所用覆盖材料的深度。利用这些知识，具体 将制定危险场地补救准则，并直接向采矿部门提供。 行业和监管机构。因此，该项目的成果将对经济和社会有价值。在 此外，我们的研究结果将作为一个全球模板，以减轻人类和环境健康问题， 受矿山和冶炼厂影响的地区。

ABSTRACT (Project 5: Maier, Neilson, Babst-Kostecka, Rasmussen) Soil contamination with trace elements in the vicinity of mining sites and smelters poses a serious threat to humans and the environment around the globe. Revegetation of mine tailings to minimize the dispersal of pollutants via wind or ground water (i.e. phytoremediation) is a promising “green” and low-cost intervention to toxic exposures. Unfortunately, plant growth is inhibited on most tailings, making it necessary to provide additional healthy substrate for seed germination and seedling growth. The current practice is the installation of an uncontaminated soil-gravel-rock cap over the tailings prior to plant seeding, with stockpiles of such material being readily available, a technology known as “cap and plant”. However, critical knowledge gaps regarding plant-soil interactions have prevented a broad and efficient implementation of this technology. The primary objective of this project is to identify the optimal strategy for generating a lasting vegetation cover at hazardous mining sites. The guiding hypothesis is that the biophysicochemical properties of capping material are critical for the development of robust root systems that can propagate into the underlying contaminated mine tailings. Using an innovative experimental design, this project will develop specific soil health indices and assess the effects of capping material depth and quality on root system architecture in a prospective plant species known as saltbush (Atriplex lentiformis) for phytoremediation. Various capping materials from stockpiled overburden and adjacent natural deposits will be tested in three consecutive greenhouse studies that bring together advanced ecological, genomic, and soil health assessments. Specifically, root system development will be monitored using a noninvasive phenotyping method based on rhizotrons, filled with different combinations of capping material and mine tailings from Superfund sites across the US Southwest. Once the optimal soil and plant parameters are identified, possibilities to amend existing but low-quality capping material in a cost-effective way will be explored. This project will yield an unprecedented mechanistic understanding of concurrent changes in plant root system architecture and function in response to the quality and depth of capping materials used for mine tailing restoration. Capitalizing on this knowledge, specific guidelines towards the remediation of hazardous sites will be developed and directly transferred to the mining industry and regulators. As such, the project outcome will be valuable for the economy and society. In addition, our findings will serve as a global template for mitigating human and environmental health issues in areas affected by mines and smelters.