Hebei and China Geological Survey Key Laboratory of Groundwater Remediation, Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, Shijiazhuang 050061, China; School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China.
School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China.
J Environ Manage. 2022 Nov 15;322:116141. doi: 10.1016/j.jenvman.2022.116141. Epub 2022 Sep 5.
The vegetation deterioration and pollution expansion from non-ferrous metal tailings pond have been found in many countries leading to water soil erosion and human health risk. Conventional ecological remediation technologies of mine tailings such as capping were costly and elusive. This study provided an economic and effective model as an alternative by substrate amelioration and vegetation restoration. A field experiment was carried out on a silver tailings pond in southwest China. Tailings substrate was ameliorated by adding organic matter (decomposed chicken manure, DCM), structural conditioner (polyacrylamide, PAM), water-retaining agent (acrylic acid-bentonite water-retaining agent, AAB), and heavy metal immobilizer (biofuel ash, BFA), which were optimized by laboratory experiment. Native heavy metal hyperaccumulator, Bidens pilosa, was colonized. Vegetation coverage and plant height of Bidens pilosa reached about 80% and over 30 cm respectively after 3 months, and the turbidity of tailings leaching solution decreased by 60%. The practice showed that the proportion of available heavy metals in tailings substrate was significantly lower than that in the soil surrounding mining area. Immobilization didn't have stabilization effect on Cd, Zn, and Pb, and As was only 0.002%, phytoremediation had stabilization effect of Cd, Zn, As, and Pb were 2.5-3.5%, 1-2%, 0.25-0.5%, and 0.25-0.75%. Phytoremediation was more effective significantly in controlling heavy metal pollution risk of tailings than immobilization. These results provided a new ecological remediation OSA-NHC model, meaning a combination of optimal substrate amelioration and native hyperaccumulator colonization, which could achieve vegetation restoration and augment heavy metal pollution control in non-ferrous metal tailings pond.
已在许多国家发现，有色金属尾矿库的植被恶化和污染扩张导致水土流失和人类健康风险。传统的矿山尾矿生态修复技术，如封盖，成本高且难以实现。本研究通过基质改良和植被恢复提供了一种经济有效的替代方案。在中国西南部的一个银尾矿库进行了现场试验。通过添加有机物（分解鸡粪，DCM）、结构调节剂（聚丙烯酰胺，PAM）、保水剂（丙烯酸-膨润土保水剂，AAB）和重金属固定剂（生物燃料灰，BFA）对尾矿基质进行改良，通过实验室实验进行优化。定植了本地重金属超富集植物，鬼针草。鬼针草的植被覆盖率和株高分别达到约 80%和 30 厘米以上，尾矿浸出液的浊度降低了 60%。实践表明，尾矿基质中有效态重金属的比例明显低于矿区周围土壤中的比例。固定化对 Cd、Zn 和 Pb 没有稳定作用，As 仅为 0.002%，植物修复对 Cd、Zn、As 和 Pb 的稳定作用分别为 2.5-3.5%、1-2%、0.25-0.5%和 0.25-0.75%。与固定化相比，植物修复对控制尾矿重金属污染风险更为有效。这些结果提供了一种新的生态修复 OSA-NHC 模型，即优化的基质改良与本地超富集植物定植的结合，可以实现有色金属尾矿库的植被恢复和增加重金属污染控制。
