| 摘要: |
| 酸性矿山废水（acid mine drainage，AMD）污染是阻碍矿山生态自然恢复的最大难题。利用以植物修复为主的生物策略控制矿山潜在污染的效费比更好且更可持续，但修复土壤存量污染、遏制增量污染仍是首要问题。其中土壤存量污染是短期内植被恢复能否成功的决定因素，而增量污染是植被恢复能否持续的决定因素。本文以铜矿排土场为例，采用石灰+鸡粪+钙镁磷肥+微生物的原位综合改良方法与栽植乔灌木袋苗+混播乔灌草种子的直接植被快速重建模式，开展了基于生态复垦的污染土壤综合改良修复效应研究。结果显示：综合改良修复后的土壤pH由改良前的2.84上升到7.83，生态复垦1 a后则轻微下降到6.72，而土壤阳离子交换量（CEC）、有机质（OM）、全氮（TN）、全磷（TP）、全钾（TK）等含量相比改良前分别增加1.98倍、32.96倍、11.74倍、2.38倍、3.64倍，生态复垦1 a后除TK含量略有下降外，CEC、OM、TN、TP含量相比改良后则分别增加了1.08倍、1.29倍、1.25倍、1.03倍；综合改良修复后的土壤净产酸量（net acid generation，NAG）、酸性中和能力（acid neutralizingcapacity，ANC）、NAG-pH值分别由改良前的17.33 kg·t−1（以H2SO4计）、−23.67 kg·t−1（以H2SO4计）和2.53显著（P＜0.05）提高到0 kg·t−1、38.33 kg·t−1和8.43，其中土壤NAG-pH和ANC在生态复垦1 a后相比改良后显著（P＜0.05）降低到5.90和0.13 kg·t−1（以H2SO4计），但土壤NAG则无显著变化；综合改良和生态复垦1 a后的铜（Cu）、锌（Zn）、镉（Cd）、铅（Pb）等重金属全量相比原始土壤均无显著性变化，但其残渣态比例均呈增大趋势，而且也均是其主要赋存形态。在AMD污染严重且富硫化矿业废弃地中，借助基于综合改良和直接植被的生态复垦技术，重建可自维持的土壤-微生物-植物生态系统是非常必要且有效的。 |
| 关键词: 铜矿排土场 土壤改良 产酸潜力 重金属形态 生态复垦 |
| DOI：10.7515/JEE212037 |
| CSTR：32259.14.JEE212037 |
| 分类号: |
| 基金项目:江铜集团科技项目（2018012） |
| 英文基金项目:Technology Development Project of Jiangxi Copper Co., Ltd. (2018012) |
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| Study on remediation effects of contaminated soil in copper mine waste-dumps based on ecological reclamation |
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CHENG Rui
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Shenzhen Ruyin Ecological Construction Co., Ltd., Shenzhen 518057, China
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| Abstract: |
| Background, aim, and scope The exploitation of mineral resources has inevitably caused substantial damage and serious pollution to the ecological environment. To manage the problems of ecological degradation and environmental pollution, restoration mine ecology is considered to be highly necessary and effective. However, acid mine drainage (AMD) pollution is the major obstacle to the ecological natural restoration of metal mines. Bioremediation based on phytoremediation has been considered appropriate, since it is a cost effective and sustainable strategy. However, remediating pollution and curbing its increase are the keys to solving the problems of mine reclamation. Among various factors, soil stock pollution is the decisive factor for the restoration of vegetation, and incremental pollution is the decisive factor for the sustainability of vegetation restoration. To biologically control potential pollution, this paper utilized the Yangtaowu Dump of Dexing Copper Mine in Jiangxi Province, as the research object, conducted an ecological reclamation experiment and analyzed the remediation and control effect of a soil in-situ comprehensive improvement method and the rapid reconstruction model of vegetation to remove mine pollution from the perspective of ecological engineering. Materials and methods This study adopted an in-situ comprehensive improvement method of lime, chicken feces, calcium magnesium phosphate fertilizer, and microorganisms to repair pollution and reconstruct the environment of contaminated soil in the waste dumps. Vegetation restoration technology of planting arbor and shrub seedlings and sowing seeds for trees, shrubs and grasses to quickly restore diverse vegetation communities was utilized. The characteristics of changes in the soil physical and chemical properties, acid production potential and heavy metal before and after comprehensive improvement and the ecological reclamation of copper mine dump. Results After comprehensive improvement, the soil pH increased from 2.84 to 7.83 and decreased to 6.72 one year after ecological reclamation. The contents of soil cation exchange capacity (CEC), organic matter (OM), total nitrogen (TN), total phosphorus (TP) and total potassium (TK) increased by 1.98-, 32.96-, 11.74-, 2.38- and 3.64-fold, respectively, after improvement. Except that the TK content decreased slightly, the CEC, OM, TN and TP increased by 1.08-, 1.29-, 1.25- and 1.03-fold, respectively, after one year. The soil net acid generation (NAG), acid neutralization capacity (ANC) and NAG-pH increased significantly from 17.33 kg·t−1 (calculated by H2SO4), −23.67 kg·t−1 (calculated by H2SO4) and 2.53 to 0 kg·t−1, 38.33 kg·t−1 and 8.43 after comprehensive improvement (P＜0.05). After one year, the NAG-pH and ANC decreased significantly to 5.9 and 0.13 kg·t−1 (P＜0.05), but the NAG did not change significantly. The total amount of Cu, Zn, Cd and Pb did not change significantly after improvement and one year later, but the proportion of residual states increased. These were also the main forms that occurred. Discussion From the temporal and spatial changes of soil environmental quality, the in-situ comprehensive improvement measures significantly improved the soil ANC and NAG-pH reduced the NAG, and improved the physical and chemical properties of soil. After one year of ecological reclamation, the soil ANC decreased significantly and was accompanied by the restoration of net acid production potential. However, the soil still maintained a neutral environment and did not appear to be acidified. The results show that in-situ comprehensive improvement measures can quickly repair soil pollution and reconstruct the soil environment in a short period of time. In view of the timeliness of some soil improvement materials, it is necessary to increase the amount of materials. The biological strategy based on vegetation restoration also effectively controlled the potential mine pollution and consolidated or even strengthened the effect of remediation of soil pollution. Even if the soil has a net acid production potential, the vegetation rapid reconstruction model can quickly restore the diversified vegetation in 2—3 months and effectively prevent soil acidification. Conclusions The bioremediation strategy involves reconstructing a stable soil-microorganism-vegetation system in the mine waste dumps with serious pollution and large amounts of sulfide. This approach is necessary and effective with the help of soil comprehensive improvement technology and a vegetation rapid restoration model based on a strategy of manual intervention. Recommendations and perspectives The high acid potential of mine sulfide rich soil results in a short “window period” of vegetation restoration. Thus, efficient manual intervention measures are critical. This study can provide a reference for studies of contaminated soil remediation technology or intervention technology in mine waste dumps based on the strategy of biologically controlling potential pollution. |
| Key words: copper mine dump soil improvement acid production potential heavy metal form ecological reclamation |
