Department of Environmental, Agricultural and Analytical Chemistry, University of Glasgow, Glasgow G12 8QQ, Scotland, UK.
Chemosphere. 2013 Jan;90(3):952-7. doi: 10.1016/j.chemosphere.2012.06.038. Epub 2012 Jul 21.
During a larger study to screen candidate plant species for phytoremediation of diesel fuel-contaminated soils, it was observed that at relatively low levels of diesel fuel contamination, delayed shoot/root emergence and reduced germination was observed for the majority of plant species investigated. It was theorised that these effects were the result of acute phytotoxicity, caused by the volatile fraction of diesel fuel, with results supporting this theory. This finding was investigated further in the current study. Headspace analysis of diesel fuel showed that between 5% and 10% of diesel fuel consisted of compounds that would volatilise at 20°C, with the most predominant compounds identified being the isomers of xylene (m-, o- and p-), n-alkanes (C9-C12) and alkylbenzenes. There were also low levels of toluene, branched cyclohexanes (methyl-, to butylcyclohexane) and alkenes. Of particular interest were branched cyclohexanes as little work has previously been reported on these compounds. To explain the phytotoxic effect of the volatile fraction of diesel fuel and attribute the effect to a specific compound or group of compounds within diesel fuel, seeds were germinated in petri dishes contaminated with a number of pure branched cyclohexanes. An unusual pattern of germination was apparent, with results varying depending on grass species and the length of cyclohexane branching. Results showed ethyl- and butyl-cyclohexane had a significant effect on the germination rate of selected grass species whereas methyl- and propyl-cyclohexane had little effect.
在一项更大的研究中，筛选候选植物物种用于修复受柴油污染的土壤，研究人员观察到，在相对较低的柴油污染水平下，大多数调查的植物物种的芽/根延迟出现，发芽率降低。理论上，这些效应是柴油燃料挥发分引起的急性植物毒性的结果，结果支持了这一理论。本研究进一步探讨了这一发现。柴油燃料的顶空分析表明，5%至 10%的柴油燃料由在 20°C 下挥发的化合物组成，鉴定出的最主要化合物是二甲苯（间、对和邻）、正构烷烃（C9-C12）和烷基苯的异构体。也有少量的甲苯、支化环己烷（甲基、叔丁基环己烷）和烯烃。特别引人关注的是支化环己烷，因为以前对这些化合物的研究很少。为了解释柴油燃料挥发分的植物毒性效应，并将这种效应归因于柴油燃料中的特定化合物或化合物组，研究人员在受污染的培养皿中用几种纯支化环己烷使种子发芽。发芽出现了一种不寻常的模式，结果因草种和环己烷支化长度而异。结果表明，乙基和丁基环己烷对所选草种的发芽率有显著影响，而甲基和丙基环己烷的影响很小。
