Departamento de Ecología de la Biodiversidad, Instituto de Ecología, Universidad Nacional Autónoma de México, C.P. 83250, Hermosillo, Sonora, Mexico.
Departamento de Ecología Funcional, Instituto de Ecología, Universidad Nacional Autónoma de México, C.P. 04510, Ciudad de México, Mexico.
Environ Sci Pollut Res Int. 2020 Nov;27(31):39635-39650. doi: 10.1007/s11356-020-09841-7. Epub 2020 Jul 10.
Past mining activities have left a legacy of abandoned mine tailing deposits whose metal contaminants poses serious risks to ecosystems and human health. While the development of a vegetated cover in mine tailings can help in mitigating these risks, the local factors limiting plant establishment in these sites are not well understood, restricting phytostabilization efforts. Here, we explore some of the barriers that limit seedling establishment of two species (Vachellia farnesiana and Prosopis velutina) in a mine tailing deposit located in Nacozari, Sonora, Mexico, and assess whether compost addition can help in overcoming these barriers in pot and field experiments. Our field observations found 20 times more carbon and at least 4 times more nitrogen concentration in areas under vegetated patches than in non-vegetated areas, while a previous study found no difference in metal concentrations and other physicochemical parameters. This suggests that organic matter and nutrients are a major limitation for plant establishment. In agreement with this, species failed to establish without compost addition in the field experiment. Compost addition also had a positive effect on biomass accumulation, pH and microbial activity, but increased the substrate soluble concentration of As, Cu, and Zn. Nonetheless, only Cu, K, and Mo in P. velutina accumulated in tissues at levels considered toxic for animal consumption. Our study documents that compost addition facilitated plant establishment for the phytostabilization of mine tailings and help to prevent the dispersion of most metal contaminants via animal consumption. We encourage the use of complementary strategies to minimize the risk of dispersion of metal contaminants.
过去的采矿活动留下了废弃尾矿的遗留物，其金属污染物对生态系统和人类健康构成严重威胁。虽然在尾矿中发展植被覆盖可以帮助减轻这些风险，但这些地点限制植物定植的局部因素尚未得到很好的理解，限制了植物稳定化的努力。在这里，我们探讨了一些限制两种物种（Vachellia farnesiana 和 Prosopis velutina）在墨西哥索诺拉州纳科萨里的尾矿库中幼苗定植的障碍，并评估了添加堆肥是否可以在盆栽和田间实验中帮助克服这些障碍。我们的实地观察发现，植被斑块下的碳浓度比非植被区高 20 倍，氮浓度至少高 4 倍，而之前的一项研究发现金属浓度和其他物理化学参数没有差异。这表明有机物质和养分是植物定植的主要限制因素。与这一观点一致的是，在田间实验中，没有添加堆肥的情况下，物种无法定植。添加堆肥还对生物量积累、pH 值和微生物活性产生了积极影响，但增加了 As、Cu 和 Zn 的基质可溶性浓度。尽管如此，只有 P. velutina 中的 Cu、K 和 Mo 在组织中积累到被认为对动物食用有毒的水平。我们的研究表明，添加堆肥促进了植物在尾矿植物稳定化中的定植，并有助于防止通过动物食用来分散大多数金属污染物。我们鼓励使用补充策略来最大程度地降低金属污染物分散的风险。
