PHYTOREMEDIATION OF TOXIC WASTE SITES

该计划的目的是探索利用植物修复环境中的有毒溶剂泄漏，特别是三氯乙烯（TCE）。杨树被使用，因为有一个广泛的背景处理这个物种。选用杂交品种H-11-11，因为它具有良好的栽培和生长特性。这些树种植在一个由西方化学公司设计的地点，并得到了华盛顿州生态部门的同意。在4年期间，98%至99%的总有机污染物已从进水中去除。在1998年期间，树木没有释放出可检测到的TCE。与对照相比，对种植土壤的分析表明，氯化物的增加相当于向细胞中添加了TCE的量。表明TCE已被广泛矿化。使用四氯化碳和过氯乙烯发现了类似的结果。细菌对TC降解的贡献可以忽略不计。在与我们场地现有条件相当的条件下，杨树将对修复有用。迈克·胡珀博士（项目7号）的研究表明，经过TCE处理的杨树的碎屑对几种昆虫无害。未来的工作将使用14c标记的TCE来测量TCE的吸收速率和碳的命运。我们还将开发一种能够在各种地理区域解毒各种常见污染物的植物库。我们还初步成功地引入了一种降解酶的基因，细胞色素P450 IIE1。这些植物产生的第一次降解产物是TCE的35倍。我们正在申请许可在我们的现场测试场地使用它们。我们已经开始与其他几项研究合作，以获得能够扩大植物解毒化合物范围的基因。

The purpose of this program is to explore the use of plants to remediate toxic solvent spills, especially trichloroethylene (TCE), in the environment. Poplars were used as there is an extensive background dealing with this species. The hybrid H-11-11, Populus trichocarpa X P. deltoides, was used as it has favorable cultivation and growth characteristics. The tress were planted at a site designed by Occidental Chemical Corporation with concurrence of the Washington State Department of Ecology. Over the 4-year period 98-99% of the TCE has been removed from the influent water. During 1998 there was no detectable TCE transpired by the trees. Analysis of the planted soil versus controls showed an increase in chloride that was equivalent to the amount of TCE added to the cells. indicating that the TCE has been extensively mineralized. Comparable results were found using carbon tetrachloride and perchloroethylene. The contribution of bacteria to the degradation of the TC was negligible. Under conditions comparable to what exists at our site, poplars will be useful for remediation. Studies with Dr. Mike Hooper (Project #7) have indicated that the detritus from TCE treated poplars is harmless to several insects tested. Future work will use 14C-labeled TCE to measure the rate of uptake and the fate of the carbon of TCE. We will also develop a repertoire of plants that can detoxify a variety of common pollutants in a variety of geographic areas. We have also had preliminary success with the introduction of genes for a degradative enzyme, cytochrome P450 IIE1. These plants formed up to 35 times as much of the first degradative product of TCE. We are in the process of applying for permission to use them at our field test site. We have entered into collaborations with several other investigations to obtain genes that will broaden the range of compounds that can be detoxified by plants.