Project 9: Phytostabilization of Mine Tailings in the Southwestern

尾矿处理场普遍存在于世界各地的干旱和半干旱地区，包括美国西南部。未回收的采矿废物通常会保持数十到数百年的未生长状态，暴露的尾矿可能会通过风和水侵蚀扩散到大片地区。包括金属毒性、低有机物、酸性pH、高盐度、极端温度、低降水和严重压力的微生物群落在内的多种因素共同导致了植被的缺乏。对于这类尾矿，风载扩散是附近社区和环境敏感地区的重要暴露途径。 具体地说，尾矿是空气污染的一个重要来源，其形式为颗粒物10亩(PM10)和2.5亩(PM2.5)。即使在没有有毒金属的情况下，暴露在这些颗粒物中也会导致呼吸道和其他疾病。事实上，许多场所还含有有毒金属，这加剧了对人类健康的影响。针对这类地点的一种经济有效的补救技术是植物稳定化，即建立一个永久的植被覆盖，不会将金属积累到植物新梢组织中。虽然前景看好，但目前在可访问的科学文献中很少有关于这项技术的文献。该项目的总体目标是确定植物-微生物-金属相互作用如何影响干旱尾矿恢复植被的短期和长期需求和机制，并确定表明成功修复的生物和物理化学标记。这个项目的重点是考察植物稳定化的现场应用，同时保留一些关键的基础研究问题，这些问题被认为是该领域成功的重要因素。具体目标包括：(1)将植物稳定化 该项目的目的是：(1)确定从温室到田间的植物稳定化技术；(2)确定尾矿初始生物物理化学特性的多变量空间分析是否可用作植物稳定化成功的有用指标；(3)评估尾矿恢复植被后“健康”土壤随时间变化的进展情况；(4)确定微生物接种剂对植物稳定化的影响，包括植物生物量的生产和根际群落的发展。

Mine tailings disposal sites are prevalent in arid and semiarid regions throughout the world including the US Southwest. Unreclaimed mining wastes generally remain unvegetated for tens to hundreds of years, and exposed tailings can spread over vast areas via wind and water erosion. A combination of factors, including metal toxicity, low organic matter, acidic pH, high salinity, extreme temperatures, low precipitation, and severely stressed microbial communities contribute to this lack of vegetation. For such tailings, wind-borne dispersion is an important exposure route for nearby communities and environmentally sensitive areas. Specifically, tailings are a significant source of air pollution in the form of particulates <10 ¿mu¿m (PM10) and <2.5 ¿mu¿m (PM2.5). Exposure to these particulates has consequences for respiratory and other diseases even in the absence of toxic metals. The fact that many sites additionally contain toxic metals exacerbates the human health impact. A cost effective remedial technology for such sites is phytostabilization, the establishment of a permanent vegetative cover that does not accumulate metals into plant shoot tissues. While of great promise, there is currently little documentation of this technology in accessible scientific literature. The overall goal of this project is to determine how plant-microbe-metal interactions affect the short- and long-term requirements for, and mechanisms of, revegetation of arid mine tailings and to identify the biological and physico-chemical markers that indicate successful remediation. This project focuses on examining field application of phytostabilization while retaining several key basic research questions identified as important for success in the field. Specific objectives include: (1) to translate phytostabilization technology from the greenhouse to the field; (2) to determine if a multi-variate, spatial analysis of initial biophysico-chemical characteristics of mine tailings can serve as a useful predictor of phytostabilization success; (3) to evaluate the progress toward development of a "healthy" soil as a function of time following revegetation of mine tailings; and (4) to determine the influence of microbial inocula on phytostabilization including plant biomass production and development of the rhizosphere community.