Phytostabilization Technology for Mining Wastes in Arid and Semiarid Environments: Plant-Microbe-Metal Indicators to Predict Sustainability

项目总结(项目8；Maier，Chorover，Neilson，Barton) 尾矿是粉碎矿石和提取铜等金属的过程中产生的废物 采矿过程。这种废物缺乏使土壤成为植物适宜栖息地的特性，包括 土壤结构、有机质、养分和微生物。这些尾矿矿藏，范围从几个 到数千英亩的面积，可能会保持几十年或更长时间的不毛之地，导致风和水侵蚀成 周围的环境。特别令人担忧的是遗留的尾矿，这些尾矿经常被遗弃和 具有高度酸性的特点，有毒金属如砷和铅的水平升高。通常是这些 金属与很小的尾矿颗粒有关，很容易被风吹走。因此，这些尾矿具有 有可能影响这类废弃场周围地区的人类和环境健康。整体而言 本项目的目标是了解、改进和制定针对干预性 被称为植物稳定化的修复技术。植物稳定化涉及建立一种 在尾矿上使用不会在其地上部组织中积累金属的植物的营养盖子。相反， 金属被隔离在根部地带，导致风或水的流动性降低。我们的研究 到目前为止，还表明植物稳定化可以改变尾矿中金属的形态。 降低它们的毒性。该项目的具体目标是：(1)继续进行堆肥的长期田间试验-- 铁王矿和洪堡冶炼厂超级基金场址尾矿的辅助植物稳定化 了解这项技术的长期结果(5-10年)；(2)评估具体的互动 在根、微生物和金属中，它们推动了在尾矿中生长的植物的成功(或失败)； 以及(3)利用所获得的知识和与采矿业建立的伙伴关系 将我们的研究扩展到更多的地点，以确定植物稳定化成功的通用指标。这些 指标将是制定关于植物稳定的指南的基础，可供 采矿业和监管机构管理废弃的尾矿场以及计划 结案了。

PROJECT SUMMARY (Project 8; Maier, Chorover, Neilson, Barton) Mine tailings are wastes leftover following the crushing of ores and extraction of metals such as copper during the mining process. This waste is devoid of the properties that make soils a suitable habitat for plants including soil structure, organic matter, nutrients and microorganisms. These tailings deposits, which range from several to thousands of acres in size, can remain barren for decades or longer resulting in wind and water erosion into the surrounding environment. Of particular concern are legacy mine tailings which are often abandoned and are characteristically highly acidic with elevated levels of toxic metals such as arsenic and lead. Often these metals are associated with very small tailings particles that are easily windborne. Thus, these tailings have the potential to impact both human and environmental health in areas surrounding such waste sites. The overall goal of this project is to understand, refine, and develop industry and regulatory guidance for an interventional remediation technology known as phytostabilization. Phytostabilization involves the establishment of a vegetative cap on mine tailings using plants that do not accumulate metals into their shoot tissues. Instead, the metals are sequestered in the root zone resulting in decreased mobility either by wind or water. Our research to date also suggests that phytostabilization can act to change the form of metals in mine tailings thereby reducing their toxicity. The specific aims of this project are to (1) continue a long-term field trial of compost- assisted phytostabilization of the mine tailings at the Iron King Mine and Humboldt Smelter Superfund site to understand the longer-term outcomes (years 5-10) of this technology; (2) evaluate the specific interactions among roots, microorganisms and metals that drive the success (or failure) of plants growing in mine tailings; and (3) use the knowledge gained and a partnership that has been established with the mining industry to expand our research to additional sites to identify universal indicators of phytostabilization success. These indicators will be the basis for development of a guidance on phytostabilization that can be used by both the mining industry and regulators to manage abandoned mine tailings sites as well as sites that are slated for closure.