Dechlorination of chloroacetanilide herbicides by plant growth regulator sodium bisulfite
Dechlorination of chloroacetanilide herbicides by plant growth regulator sodium bisulfite
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植物生长调节剂亚硫酸氢钠对氯乙酰苯胺类除草剂的脱氯作用
DOI：
10.1016/j.watres.2009.05.002
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发表时间：
2009-08-01
期刊：
影响因子：
12.8
通讯作者：
Hao, Ce
中科院分区：
文献类型：
--
作者：
Bian, Haitao;Chen, Jingwen;Hao, Ce
在地下水和地表水中经常检测到氯乙酰胺除草剂，并对水生生物群构成高风险。在这项研究中，使用中国使用的植物生长调节剂（NAHSO3）被用于去除三种氯乙酰苯胺除草剂，包括α，乙酰氯和S-米洛克勒。在中性条件下，这些除草剂被NAHSO3迅速脱氯。随着pH，温度和NAHSO3浓度的升高，脱氯加速。动力学分析和质谱鉴定表明，遵循S（n）2亲核取代的反应，其中氯被反应性的Specie硫酸盐代替。 Alachlor及其异构体乙酰氯的反应速率相似，而与具有更大空间障碍和较弱的亲电性较弱的S-核酸相比，它们更容易转化。转化产物是氯乙烷乙烷磺酸（ESA），它们在自然环境中通过常见的代谢途径在自然环境中作为这些除草剂的主要代谢产物遇到，与父母除草剂相比，对绿色藻类的毒性较小。这些结果表明，NAHSO3可以通过在水生环境中通过亲核取代和脱氯的形式加速氯乙酰烷基除草剂向毒性较小的转化产物。 NAHSO3可能用于从废水废水，溢出物和意外排放中去除氯乙酰胺除草剂。 （c）2009 Elsevier Ltd.保留所有权利。
Chloroacetanilide herbicides are frequently detected in groundwater and surface waters, and pose high risks to aquatic biota. In this study, sodium bisulfite (NaHSO3), a plant growth regulator used in China, was used to remove three chloroacetanilide herbicides including alachlor, acetochlor and S-metolachlor. These herbicides were rapidly dechlorinated by NaHSO3 in neutral conditions. The dechlorination was accelerated with increasing pH, temperature and NaHSO3 concentrations. Kinetic analysis and mass spectrum identification revealed that the reaction followed S(N)2 nucleophilic substitution, in which the chlorine was replaced by the reactive specie sulfite. Alachlor and its isomer acetochlor had similar reaction rates, whereas they were more readily transformed than S-metolachlor that had larger steric hindrance and weaker electrophilicity. The transformation products were chloroacetanilide ethane sulfonic acids (ESAs), which were also encountered as major metabolites of these herbicides in natural environment via common metabolic pathways and were less toxic to green algae compared to the parent herbicides. These results indicate that NaHSO3 can accelerate transformation of chloroacetanilide herbicides to the less toxic transformation products by nucleophilic substitution and dechlorination in aquatic environment. NaHSO3 can be potentially used for the removal of chloroacetanilide herbicides from wastewater effluent, spill sites and accidental discharge. (C) 2009 Elsevier Ltd. All rights reserved.