Gan Jianying, Wang Qiquan, Yates Scott R, Koskinen William C, Jury William A
Department of Environmental Sciences, University of California, Riverside, CA 92521, USA.
Proc Natl Acad Sci U S A. 2002 Apr 16;99(8):5189-94. doi: 10.1073/pnas.042105199. Epub 2002 Apr 9.
Halogenated organic compounds (XOCs) are among the most widely used synthetic chemicals. Many XOCs are recalcitrant to natural degradation and have become prominent environmental contaminants. One group of such XOCs are the heavily used chloroacetanilide herbicides. We have found that chloroacetanilide herbicides are rapidly dechlorinated in water, sand, and soil by thiosulfate salts under ambient conditions. Structural and kinetics analysis suggests that the reaction occurred by S(N)2 nucleophilic substitution, in which the chlorine was replaced by thiosulfate and the herbicide was detoxified. Laboratory studies showed that this reaction could be used for removing residues of chloroacetanilide herbicides in water, soil, and sand. Our findings also suggest that some other XOCs may be subject to this reaction. Because common thiosulfate salts are innocuous products (e.g., fertilizers) and the reaction selectively detoxifies XOCs at low thiosulfate levels, this discovery may lead to a new way for safe removal of certain XOCs from the environment.
卤代有机化合物（XOCs）是使用最为广泛的合成化学品之一。许多XOCs对自然降解具有抗性，已成为显著的环境污染物。这类XOCs中的一组是大量使用的氯代乙酰苯胺类除草剂。我们发现，在环境条件下，氯代乙酰苯胺类除草剂在水、沙子和土壤中会被硫代硫酸盐迅速脱氯。结构和动力学分析表明，该反应通过S(N)2亲核取代发生，其中氯被硫代硫酸盐取代，除草剂被解毒。实验室研究表明，该反应可用于去除水、土壤和沙子中氯代乙酰苯胺类除草剂的残留。我们的研究结果还表明，其他一些XOCs可能也会发生这种反应。由于常见的硫代硫酸盐是无害产品（如肥料），且该反应在低硫代硫酸盐水平下能选择性地使XOCs解毒，这一发现可能会为从环境中安全去除某些XOCs带来一种新方法。
