水体中甲基叔丁基醚(MTBE)的植物修复

研究凤眼莲对水体中甲基叔丁基醚(MTBE)的吸收转移规律和富集特征. 结果表明: 胁迫5 d后, 处理Ⅰ(整株凤眼莲)中MTBE的平均浓度减少了94.25%, 处理Ⅱ(去叶凤眼莲)中MTBE的平均浓度减少了近50%, 处理Ⅰ比处理Ⅱ约减少44%, 而处理Ⅲ（对照）中MTBE的平均浓度只减少7.3%, 表明凤眼莲叶片的蒸腾作用是水溶液中MTBE减少的主要原因. 将实验所得数据进行回归分析得出： 20 ℃时, 水体中MTBE消失符合一级动 力学方程； 处理Ⅰ、 处理Ⅱ的消失速率明显大于处理Ⅲ. 凤眼莲暴露在ρ_MTBE<1 110 mg/L溶液中时, 培养5 d未观察到MTBE对植物的毒性, 蒸腾量与生物量比值变化不明显,当ρ_MTBE=1 480 mg/L时, 凤眼莲的蒸腾量与生物量比值明显减小, 凤眼莲叶片边缘干枯和萎黄. MTBE在凤眼莲根、 茎、 叶中的分布比例约为1 ∶1.5 ∶0.5, 其分布规律为： 茎>根>叶.

Phyto-remediation of Methyltert-butylether(MTBE) in Polluted Water

Absorption and transportation of methyltert butylether(MTBE) in water by Eichhornia crassipes were studied. Results show that concentrations of MTBE in treatments Ⅰ,Ⅱ, and Ⅲ(control) were decreased by 94.25％, 50％, and 7.3％, respectively when they were exposed to MTBE for 5 d. This illustrates that the transpiration of the leaves of Eichhornia crassipes was the major cause for the reduction in concentration of MTBE in water solution. Regression analysis of the experimental data was performed, showing that the disappearance of MTBE in water solution was fitted to first order kinetic equation. Disappearance rate of MTBE in water in treatment Ⅲ was obviously lower than that in treatment Ⅰor Ⅱ. This further demonstrates that transpiration plays a crucial role in the elimination of MTBE in water solution. No harm was observed and no difference in the ratio of transpiration quantity to biomass emerged when Eichhornia crassipes was exposed to MTBE at a concentration less than 1 110 mg/L for 5 d. Ratio of transpiration quantity to biomass reduced obviously and leaf edge was dried up and became etiolate when Eichhornia crassipes was exposed to MTBE at concentration 1 480 mg/L. By measuring the contents of MTBE in the root, stalk, and leaf of Eichhornia crassipes, it was found that concentration ratio of MTBE in root, stalk, and leaf was 1 ∶1.5 ∶0.5, which showed that the order of MTBE concentration in the tissues was stalk>root>leaf.