樟树对土壤中PAHs的修复及其影响因子

Phytoremediation of polycyclic aromatic hydrocarbons in soils by Cinnamomum camphora and impact factors

采用室内盆栽实验,利用柴油设置2 g·kg-1(L1),10 g·kg-1(L2)和50 g·kg-1(L3)模拟PAHs浓度梯度,对盆栽的1年生樟树幼苗对PAHs的修复机制及影响因子进行研究。结果表明:(1)不同浓度PAHs污染(L1、L2、L3)水平下,樟树幼苗土壤中PAHs的去除率分别为85.86%、91.95%、80.80%,均高于无植物处理。(2)PAHs在樟树不同器官中的积累浓度不同。中、低浓度污染处理水平(L2、L1)下,樟树各器官对PAHs的积累作用均表现为:叶>根>干;高浓度污染处理水平(L3)下则表现为根>叶>干。不同污染处理(L1、L2、L3)水平下,樟树吸收累积作用修复PAHs污染土壤的贡献率分别为64.26%、22.81%、11.39%。(3)随着PAHs污染浓度的增大,樟树不同部位生物浓缩系数逐渐减小。叶和根是樟树富集PAHs的主要部位。(4)5cm土壤温度和多酚氧化酶是影响樟树修复PAHs污染土壤的关键因子,真菌、放线菌数量和磷酸酶活性可以作为土壤PAHs污染评价的生物指标。研究结果可为南方城市PAHs污染修复优良绿化树种的筛选提供理论依据。

By pot experiments in greenhouse, phytoremediation and its impact factor were investigated for one-year-old Cinnamomum camphora treated with unplanted soils （control） and at three diesel concentrations （2 g·kg^-1 （L1） , 10 g·kg^-1 （L2） and 50g·kg^-1 （L3） ） to stimulate different levels of PAHs pollution. The results show that the removal rates of PAlls by C. camphora were 85.86%, 91.95% and 80.80% at L1, L2 and L3 levels, and all were higher than unplanted treatment; PAHs accumulations in the organs of C. camphora were different, at L2 and L1 levels, the accumulation of PAHs by C. camphora was in an order： leaf〉root〉stem, while it was root〉leaf〉stem at L3 levels; and the contribution rates for PAils phytoremediation by absorption and accumulation of C. camphora were 64.26%, 22.81% and 11.39% at L1, L2 and L3 levels; the bio-concentration factors became smaller with the increase of PAHs pollution, and leaf and root were the important organs for C camphora to enrich PAHs; the temperature at 5 cm soil and polyphenol oxidase were the key factors for PAHs phytoremediation by C. camphora; the fungi, actinomycetes population and phosphatase activity were suggested as the biological indicators of soil PAHs pollution. The findings could provide a theoretic evidence for screening good trees which have great effect on remediation of PAHs pollution.