花卉植物对Cd、As、Pb污染农田的修复及其精油应用

Phytoremediation of Cd, As, Pb contaminated farmland by flower plants and extracted essential oil application

关键词:  重金属复合污染, 农田, 植物修复, 植物精油, 抑菌

Key words:  heavy metal contamination, farmland, phytoremediation, essential oil, antibacterial

摘要:

为提高植物修复的经济价值,该文选取孔雀草、波斯菊和矢车菊三种附加值较高的花卉植物,考察其对广西某矿区Cd、As、Pb复合污染农田的修复潜力,测定分析三种花卉植物对重金属的富集和转运能力,并从修复后植物的地上部提取精油,研究植物精油对病原菌埃希氏大肠杆菌(Escherichia coli)、金黄色葡萄球菌(Staphyloccocus aureus)、伤寒沙门氏菌(Salmonella typhimurium)的生长抑制效果,进一步探索植物精油作为洗手液添加剂的应用能力。结果表明:(1)试验区域内土壤污染严重,Cd、As全量超过风险管制值,Pb全量超过风险筛选值,属于Cd、As、Pb重度污染。(2)选取的三种花卉植物均可在试验区域较好地生长,其中孔雀草和波斯菊对Cd、Pb的富集与转运能力较强,对As的富集能力最弱但转运能力较强。与孔雀草和波斯菊相比,矢车菊除对Cd的转运能力较强外,对其他重金属的富集和转运能力均较弱。三种植物重金属富集能力大小排序为孔雀草>波斯菊>矢车菊,不同花卉对重金属富集偏好顺序依次为Cd>Pb>As。(3)从修复后的植物地上部提取精油进行研究分析发现,孔雀草精油对三种病原菌都具有良好的生长抑制效果(<10 CFU·mL^-1),且孔雀草体内富集的重金属并未影响精油中的重金属含量。另外,添加了孔雀草精油的洗手液,对金黄色葡萄球菌的生长抑制效果可延长至480 min。因此,孔雀草不仅可作为重金属复合污染农田的修复植物,而且修复后还可从植物体内提取精油作为抑菌剂。该研究结果为修复后重金属富集生物质的新型资源化利用提供了理论基础。

Abstract:

To improve the economic value of phytoremediation, three flower plants i.e. Tagetes patula, Cosmos bipinnata and Centaurea cyanus were chosen in this study to investigate their remediation and reutilization potentials. The pilot-scale experiments were carried out in Cd, As and Pb contaminated farmland near the mining area in Guangxi. The metal amounts, bioconcentration factor(BCF)and biotranslocation factor(BTF)of three flower plants towards Cd, As and Pb were analyzed and calculated. In order to develop a novel reutilization method of the harvested plants, the essential oil was extracted from the aboveground biomasses. The inhibitory effects of plant essential oil on the growth of pathogenic bacteria were studied, and the antibacterial effects of the oil as well as in the sanitizer were also investigated. The results were as follows:(1)The studied area was heavily polluted. Cd and As contents in the soil were above risk intervention values, whereas Pb content was above risk screening value. It indicated that the area was at high-level of soil contamination risk by Cd, As and Pb.(2)The studied three flower plants had good resistance to high-level contamination of Cd, As and Pb in the soil. Tagetes patula and Cosmos bipinnata extracted higher contents of Cd and Pb from the soil, whilst Cosmos bipinnata showed the lowest metal enrichment amounts. These flower plants possessed high level of BCFs and BTFs towards Cd, moderate level for Pb, but the lowest level for As. In general, the metal extraction ability of three flower plants in descending order was Tagetes patula > Cosmos bipinnata > Centaurea cyanus, and the metal enrichment preference was Cd>Pb>As.(3)The Tagetes patula oil was found to have a good inhibition effect(<10 CFU·mL^-1)towards Escherichia coli, Staphyloccocus aureus and Salmonella typhimurium. Given the high metal accumulation in Tagetes patula, no significant amounts of metals were detected in the extracted oil. It also prolongated the antibacterial effect of the sanitizer as long as 480 min. Therefore, Tagetes patula is not only preferred in the phytoremediation of metal-contaminated farmland, but also the essential oil extracted from the harvested biomasses can be developed as an antibacterial agent. This study provides the theoretical basis for the novel reutilization of metal-concentrated plants harvested from the phytoremediation.