Phytostablization of Mine Tailings

尾矿的植物稳定化

• 批准号: 6901480
• 负责人: Raina M Maier
• 金额: $ 24.5万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-04-01 至 2010-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6901480
• 关键词: environmental toxicology; environmental transport; hazardous substances; heavy metals; metal metabolism; microorganism metabolism; minings; organic chemicals; soil pollution; surfactant; toxicant interaction; waste treatment; water flow

Extensive mining activity in arid and semi-arid ecosystems of the southwestern United States has resulted in large numbers of tailings sites with elevated metal concentrations ranging between 0.1 and 5% (w/w). Many of these piles are barren or have minimal vegetation due to metal toxicity and low pH and thus are vulnerable to wind and water erosion. Phytostabilization has been proposed as an alternative economical remediation strategy to stabilize the metal contaminants and prevent human and animal exposure resulting from particle suspension (dust) in the atmosphere or dissolution in ground and surface waters. Although this strategy is receiving attention as an economical alternative to more permanent metal removal approaches, considerable research is needed to improve the feasibility of the approach as well as to systematically assess the longevity of revegetation as a remediation strategy. First, large amounts of organic matter (compost or biosolids) and water have traditionally been used for vegetation establishment, neither of which are feasible in many of the remote areas where abandoned mine tailing piles are located. Second, little research has been conducted to evaluate the time-dependent changes in physical, chemical, and biological properties of mine tailings during revegetation. Specifically, little information is available on the effect of organic matter addition, plant establishment, and the evolution of associated microbial communities on metal bioavailability, solubility and speciation. The overall goal of this project is to develop a feasible revegetation strategy for the phytostabilization of metal contaminants in mine tailing piles in arid and semi-arid ecosystems and to assess the impact of this approach on the physical, biological and chemical properties of the mine tailings. This strategy will investigate whether the specific selection of metal- and drought-tolerant native plant species in conjunction with the controlled use of a seed inoculum developed from indigenous plant growth promoting bacteria can minimize the requirement for organic matteramendment and irrigation. Second, the bioavailability, speciation, and phase distribution of contaminating metals in the plant rhizosphere will be monitored in both greenhouse and field trials in order to assess whether revegetation results in a permanent reduction in site toxicity. In addition, the effects of specific root-microbe-tailings associations on the local biogeochemistry and metal speciation of the rhizosphere will be investigated in order to identify mechanisms involved in phytostabilization and detoxification at the micrometer and submicrometer scale. Information generated from this research will define the feasibility of plant establishment as an approach to metal stabilization in mine tailings and evaluate the potential longevity of revegetation as a remediation strategy.

美国西南部干旱和半干旱生态系统的广泛采矿活动导致大量尾矿场金属浓度升高，从0.1%到5%(w/w)不等。由于金属毒性和低pH值，许多这些桩是贫瘠的或植被很少，因此容易受到风和水的侵蚀。植物稳定化已被提出作为一种替代的经济修复策略，以稳定金属污染物，防止因大气中的颗粒物悬浮(粉尘)或地下水和地表水中的溶解而导致的人和动物暴露。尽管该策略作为更永久的金属去除方法的经济替代方法而受到关注， 需要进行大量研究，以改进这一方法的可行性，并系统地评估作为补救战略的重新植被的寿命。首先，大量有机物质(堆肥或生物固体)和水传统上用于植被建设，在许多废弃的尾矿堆所在的偏远地区，这两种方法都不可行。其次，很少有研究评估尾矿在恢复植被过程中的物理、化学和生物特性随时间的变化。具体地说，关于有机质添加、植物建立和相关微生物群落对金属的演化的影响的信息很少。 生物利用度、溶解度和物种形成。该项目的总体目标是为干旱和半干旱生态系统中尾矿堆金属污染物的植物稳定化制定一项可行的植被重建战略，并评估这一方法对尾矿的物理、生物和化学性质的影响。这一战略将调查具体选择耐金属和耐干旱的本土植物物种，结合控制使用由本土植物生长促进细菌开发的种子接种剂是否可以 尽量减少有机物质改良剂和灌溉的需求。其次，将在温室和田间试验中监测植物根际污染金属的生物有效性、形态和相分布，以评估重新植被是否会永久减少场地毒性。此外，还将调查特定的根-微生物-尾矿组合对当地根际生物地球化学和金属形态的影响，以确定在微米和亚微米尺度上参与植物稳定和解毒的机制。这项研究产生的信息将确定建立工厂作为稳定尾矿中金属的一种方法的可行性，并评估作为补救战略的重新植被的潜在寿命。