Chlorinated Byproducts of Neonicotinoids and Their Metabolites: An Unrecognized Human Exposure Potential?
Chlorinated Byproducts of Neonicotinoids and Their Metabolites: An Unrecognized Human Exposure Potential?
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DOI：
10.1021/acs.estlett.8b00706
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发表时间：
2019-02-01
影响因子：
10.9
通讯作者：
LeFevre, Gregory H.
中科院分区：
文献类型：
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作者：
Wong, Kathryn L. Klarich;Webb, Danielle T.;LeFevre, Gregory H.
我们最近报道了在饮用水中首次发现的类烟碱农药及其在水处理过程中通过氯化和碱性水解转化的潜力。本研究的目的是：（1）确定类烟碱代谢物是否与饮用水暴露相关，以及（2）鉴别类烟碱及其代谢物氯化形成的产物。首次在饮用水中发现了吡虫啉的两种已知代谢产物去硝基吡虫啉和吡虫啉-尿素。67%的饮用水系统样本（9个样本中有6个）中的去硝基吡虫啉含量高于检测下限（0.03纳克/升），但在所有样本中均可检测到（最高可达0.6纳克/升）。虽然去硝基-吡虫啉的浓度低于母体类烟碱的浓度，但去硝基-吡虫啉对哺乳动物的毒性明显大于吡虫啉。使用LC-HR-ToF-MS/MS分析实验室实验的结果，我们提出了由噻虫胺，吡虫啉，去硝基-吡虫啉，吡虫啉-尿素和噻虫嗪的水解产物的氯化产生的新型转化产物的结构。在与水处理和/或吡虫啉代谢物（t（1/2）值为2.4分钟至1.0小时）和噻虫嗪水解产物（4.8小时）分布相关的时间尺度上，会形成氯化类烟碱副产物。成品饮用水中的新烟碱类代谢物以及处理和/或分配过程中可能形成的新型消毒副产物与评价烟碱类对人类健康的暴露和潜在影响相关。
We recently reported the initial discovery of neonicotinoid pesticides in drinking water and their potential for transformation through chlorination and alkaline hydrolysis during water treatment. The objectives of this research were: (1) to determine if neonicotinoid metabolites are relevant to drinking water exposure and (2) to identify the products formed from chlorination of neonicotinoids and their metabolites. Desnitro-imidacloprid and imidacloprid-urea, two known metabolites of imidacloprid, are documented for the first time in drinking water. Desnitro-imidacloprid was present above the lower level of detection (0.03 ng/L) in 67% of samples (six of nine) from drinking water systems but detectable in all samples (up to 0.6 ng/L). Although concentrations of desnitro-imidacloprid were lower than concentrations of the parent neonicotinoids, desnitro-imidacloprid exhibits significantly greater mammalian toxicity than imidacloprid. Using LC-HR-ToF-MS/MS analysis of results from laboratory experiments, we propose structures for novel transformation products resulting from the chlorination of clothianidin, imidacloprid, desnitro-imidacloprid, imidacloprid-urea, and hydrolysis products of thiamethoxam. Formation of chlorinated neonicotinoid byproducts occurs at time scales relevant to water treatment and/or distribution for the imidacloprid metabolites (t(1/2) values from 2.4 min to 1.0 h) and thiamethoxam hydrolysis products (4.8 h). Neonicotinoid metabolites in finished drinking water and potential formation of novel disinfection byproducts during treatment and/or distribution are relevant to evaluating the exposure and potential impacts of neonicotinoids on human health.