Fipronil metabolism and dissipation in a simplified aquatic ecosystem
Fipronil metabolism and dissipation in a simplified aquatic ecosystem
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DOI：
10.1021/jf025843j
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发表时间：
2003-02-26
影响因子：
6.1
通讯作者：
Tissut, M
中科院分区：
文献类型：
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作者：
Aajoud, A;Ravanel, P;Tissut, M
几种苯基吡唑类化合物是昆虫氯离子通道活性的选择性抑制剂。在这个化学家族中，氟虫腈是一种强大的杀虫剂，现在被广泛用于多种目的。使用C-14标记的氟虫腈，在简化的水生生态系统中对该分子的消散进行了3个月的研究。在该体系中，氟虫腈转化为氟虫腈的复杂过程的主要特点如下。氟虫腈水溶液经历了两次化学转化：杂环4位上侧链的光催化脱硫化和3位上腈基团的化学水解。氟虫腈从水溶液迅速转移到有机物中，不受上述化学转化的影响，但进化成两种主要代谢物，它们在4-位上的侧链上被还原或氧化。对埃及伊蚊幼虫的LC_(50)测定表明，这些衍生物是一种有效的杀虫剂(对CF3-S-R和CF3-SO2-R的LC_(50)分别为8.8 nm)。在本实验过程中，丁腈的水解过程缓慢，要么源于水溶液中的化学水解，要么源于微生物生物量内部的酶水解。氟虫腈-酰胺(3-NH2-CO-R‘)衍生物虽然比氟虫腈本身具有更强的极性，但主要与有机物结合。还检测到了其他更具极性的衍生物，但数量很少。在实验过程中没有观察到(CO)-C-14排放。
Several phenylpyrazole derivatives are selective inhibitors of chloride channel activities in insects. In this chemical family, fipronil is a powerful insecticide now widely used for several purposes. The dissipation of this molecule in a simplified aquatic ecosystem has been studied for 3 months, using C-14-labeled fipronil. The main features of the complex process leading to fipronil transformation in this system were the following. The fipronil aqueous solution was submitted to two chemical transformations: the photodependent desulfuration of the side chain bound to the 4-position of the heterocyclic ring and the chemical hydrolysis of the nitrile function bound to the 3-position. Fipronil, rapidly transferred from the water solution to the organic matter, was protected from the previously mentioned chemical transformations but evolved to give two main metabolites, which were either reduced or oxidized in the side chain on the 4-position. These derivatives were powerful insecticides as shown by LC50 measurements on Aedes aegypti larvae (LC50 for CF3-S-R and CF3-SO2-R = 8.8 nM). During the course of this experiment, nitrile hydrolysis took place slowly, originating either from the chemical hydrolysis in the aqueous solution or from enzymatic hydrolysis inside the microbial biomass. The fipronil-amide (3-NH2-CO-R') derivative, although much more polar than fipronil itself, was mostly bound to the organic matter. Other more polar derivatives were also detected but in very small amounts. No (CO)-C-14 emission was observed during the experiment.