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、巴顿） 尾矿是在采矿过程中破碎矿石和提取金属（如铜）后留下的废物。 采矿过程。这些废物缺乏使土壤成为植物适宜栖息地的特性， 土壤结构、有机质、养分和微生物。这些尾矿沉积物，范围从几个 数千英亩的面积，可以保持几十年或更长时间的贫瘠，导致风和水的侵蚀， 周围的环境。特别令人关切的是遗留的尾矿，这些尾矿往往被遗弃， 其特征是高酸性，具有高水平的有毒金属，如砷和铅。通常这些 金属与非常小的尾矿颗粒有关，这些颗粒很容易被风吹走。因此，这些尾矿具有 可能影响这些废物场周围地区的人类和环境健康。整体 本项目的目标是了解、完善和制定行业和监管指南， 修复技术称为植物稳定化。植物稳定化包括建立一个 尾矿上的植被覆盖，使用不将金属积累到其枝条组织中的植物。而是 金属被隔离在根区，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式， 降低其毒性。该项目的具体目标是：（1）继续进行堆肥的长期田间试验- 在Iron King矿和Humboldt冶炼厂超级基金场地协助植物稳定尾矿， 了解这项技术的长期结果（5-10年）;（2）评估具体的相互作用 根、微生物和金属之间的关系，决定了植物在尾矿中生长的成功（或失败）; 以及（3）利用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其他地点，以确定植物稳定成功的通用指标。这些 指标将是制定植物稳定化指南的基础， 采矿业和监管机构管理废弃的尾矿场以及预定用于 结束

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.