多年生黑麦草对覆土作用下铜尾矿的修复

Restoration of copper tailings under covering soil by perennial ryegrass

选用耐性强的草坪草进行铜尾矿的植物修复,对尾矿的复垦和重金属污染的治理有十分重要的作用。因此,本研究通过盆栽试验,研究了多年生黑麦草(Lolium perenne)对不同比例的铜尾矿基质的修复效果,具体分析了多年生黑麦草的生长状况、土壤理化性质、土壤酶活性、土壤全铜和有效态的含量以及多年生黑麦草体内铜的含量与分布。结果表明,多年生黑麦草在铜尾矿基质中能较好生长,无严重伤害。多年生黑麦草显著改善了铜尾矿基质的营养和土壤酶活性,与不种植黑麦草组比,种植多年生黑麦草组中有机质、全氮、全磷、全钾含量平均增加了55.5%、 44.1%、 30.0%和24.9%;蔗糖酶、脲酶、磷酸酶和过氧化氢酶活性平均增加了24.8%、 20.5%、 11.4%和14.2%,均存在显著差异(P<0.05)。同时,多年生黑麦草的生长和吸收作用促进了土壤铜的活化,这种活化与吸收过程共同降低了土壤铜含量,平均降幅达到12.2%,推动了铜尾矿基质的修复进程。该试验为进一步利用多年生黑麦草修复现场铜尾矿提供了思路和方法,也为其他植物对重金属尾矿的修复提供了参考和借鉴。

Lawn grass with strong tolerance plays a significant role in disposing of heavy metal pollution and repairing copper tailings by phytoremediation. Therefore, perennial ryegrass (Lolium perenne) was used to remediate different proportions of copper tailings and soil using pot experiment. The growth status of perennial ryegrass, physicochemical properties of soil, soil enzymatic activities, content of total Cu and available Cu in soil, and content and distribution in ryegrass were investigated and analyzed. The results showed that perennial ryegrass was capable of growing well in copper tailings without any serious damage. Both the nutritional ingredients and the soil enzymatic activities from the copper tailings were distinctly improved. Compared with the blank group without cultivated plants, the organic matter, total N, total P, and total K of the trial group with ryegrass plantings were increased by 55.5%, 44.1%, 30.0%, and 24.9%, respectively. The activities of invertase, urease, phosphatase, and catalase were increased by 24.8%, 20.5%, 11.4%, and 14.2%, respectively. Differences between the two groups existed(P < 0.01). Additionally, the growth and uptake by the perennial ryegrass accelerated the activation of Cu, which reduced the content of Cu in soil by 12.2% to promote the restoration process of the Cu-contaminated soil. The experimental results illustrated that it is not only possible to restore the field copper tailings by utilizing the perennial ryegrass, but it also offered a reference to recover the heavy metal contaminated tailings by using phytoremediation.