Gil-Loaiza Juliana, White Scott A, Root Robert A, Solís-Dominguez Fernando A, Hammond Corin M, Chorover Jon, Maier Raina M
Department of Soil, Water and Environmental Science, The University of Arizona, 429 Shantz Bldg., Tucson, AZ 85721, United States.
Department of Soil, Water and Environmental Science, The University of Arizona, 429 Shantz Bldg., Tucson, AZ 85721, United States; Universidad Autónoma de Baja California, Facultad de Ingeniería, Baja California 21900, Mexico.
Sci Total Environ. 2016 Sep 15;565:451-461. doi: 10.1016/j.scitotenv.2016.04.168. Epub 2016 May 13.
Standard practice in reclamation of mine tailings is the emplacement of a 15 to 90cm soil/gravel/rock cap which is then hydro-seeded. In this study we investigate compost-assisted direct planting phytostabilization technology as an alternative to standard cap and plant practices. In phytostabilization the goal is to establish a vegetative cap using native plants that stabilize metals in the root zone with little to no shoot accumulation. The study site is a barren 62-hectare tailings pile characterized by extremely acidic pH as well as lead, arsenic, and zinc each exceeding 2000mgkg(-1). The study objective is to evaluate whether successful greenhouse phytostabilization results are scalable to the field. In May 2010, a 0.27ha study area was established on the Iron King Mine and Humboldt Smelter Superfund (IKMHSS) site with six irrigated treatments; tailings amended with 10, 15, or 20% (w/w) compost seeded with a mix of native plants (buffalo grass, arizona fescue, quailbush, mountain mahogany, mesquite, and catclaw acacia) and controls including composted (15 and 20%) unseeded treatments and an uncomposted unseeded treatment. Canopy cover ranging from 21 to 61% developed after 41 months in the compost-amended planted treatments, a canopy cover similar to that found in the surrounding region. No plants grew on unamended tailings. Neutrophilic heterotrophic bacterial counts were 1.5 to 4 orders of magnitude higher after 41months in planted versus unamended control plots. Shoot tissue accumulation of various metal(loids) was at or below Domestic Animal Toxicity Limits, with some plant specific exceptions in treatments receiving less compost. Parameters including % canopy cover, neutrophilic heterotrophic bacteria counts, and shoot uptake of metal(loids) are promising criteria to use in evaluating reclamation success. In summary, compost amendment and seeding, guided by preliminary greenhouse studies, allowed plant establishment and sustained growth over 4years demonstrating feasibility for this phytostabilization technology.
矿山尾矿复垦的标准做法是铺设一层15至90厘米厚的土壤/砾石/岩石覆盖层，然后进行水力播种。在本研究中，我们研究了堆肥辅助直接种植植物稳定化技术，作为标准覆盖层和种植方法的替代方案。在植物稳定化中，目标是使用本地植物建立一个植被覆盖层，该覆盖层能在根区稳定金属，地上部分积累很少或几乎没有积累。研究地点是一个62公顷的贫瘠尾矿堆，其特点是pH值极低，铅、砷和锌的含量均超过2000mg/kg。研究目的是评估温室植物稳定化的成功结果是否可扩展到实地。2010年5月，在铁王矿和洪堡冶炼厂超级基金（IKMHSS）场地建立了一个0.27公顷的研究区域，设置了六种灌溉处理；用10%、15%或20%（重量/重量）堆肥改良的尾矿，播种了本地植物混合种（野牛草、亚利桑那羊茅、鹌鹑灌木、山地桃花心木、牧豆树和猫爪金合欢），以及对照处理，包括堆肥（15%和20%）未播种处理和未堆肥未播种处理。在堆肥改良种植处理中，41个月后形成了21%至61%的冠层覆盖，冠层覆盖与周边地区相似。未改良的尾矿上没有植物生长。种植地块在41个月后的嗜中性异养细菌数量比未改良的对照地块高1.5至4个数量级。各种金属（类金属）的地上组织积累量处于或低于家畜毒性限值，在接受较少堆肥的处理中有一些特定植物的例外情况。包括冠层覆盖百分比、嗜中性异养细菌数量和金属（类金属）地上吸收量等参数是评估复垦成功的有前景的标准。总之，在初步温室研究的指导下，堆肥改良和播种使植物得以建立并持续生长4年，证明了这种植物稳定化技术的可行性。
