Degradation of glyphosate and bioavailability of phosphorus derived from glyphosate in a soil-water system
Degradation of glyphosate and bioavailability of phosphorus derived from glyphosate in a soil-water system
复制标题
土壤-水系统中草甘膦的降解和草甘膦磷的生物利用度
DOI：
10.1016/j.watres.2019.07.007
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发表时间：
2019
期刊：
影响因子：
12.8
通讯作者：
Jaisi, Deb P.
中科院分区：
文献类型：
--
作者：
Sun, Mingjing;Li, Hui;Jaisi, Deb P.
草甘膦是世界上最常用的除草剂，可降解为毒性更大、持久性更强的产物，如氨甲基膦酸（AMPA）或无毒产物，如肌氨酸和甘氨酸。本研究采用液相色谱质谱（LC-MS）和电喷雾离子源Q萃取轨道阱质谱（ESI-Orbitrap MS）鉴定草甘膦降解产物，并结合连续萃取和稳定同位素研究了草甘膦在土壤-水系统中的降解和磷（P）产物的转化。LC-MS和ESI-Orbitrap MS结果表明，甘氨酸在早期形成，但很快被土壤微生物利用。AMPA在后期开始积累，发现其抗降解能力是草甘膦的3-6倍;而没有肌氨酸形成。18 O标记和磷酸盐氧同位素的结果允许从草甘膦衍生的无机磷（Pi）的分数的明确区分，其中约一半，然后迅速采取和土壤微生物再循环。我们的研究结果提供了优先利用草甘膦衍生的Piby微生物在土壤-水系统中的第一个证据。Piderived从这个被忽视的来源的快速循环有重要的影响，营养管理以及水质。
Glyphosate, the most commonly used herbicide in the world, can be degraded into more toxic and persistent products such as aminomethylphosphonic acid (AMPA) or non-toxic products such as sarcosine and glycine. In this study, we used liquid chromatography mass spectrometry (LC-MS) and electrospray ionization (ESI) source Q Extractive Orbitrap mass spectrometry (ESI-Orbitrap MS) to identify glyphosate degradation products and combined with sequential extraction and stable isotopes to investigate the degradation of glyphosate and transformation of phosphorous (P) product in a soil-water system. The LC-MS and ESI-Orbitrap MS results showed that glycine formed during the early stage but was rapidly utilized by soil microorganisms. AMPA started to accumulate at the late stage and was found to be 3–6 times more resistant than glyphosate against degradation; while no sarcosine was formed. The18O labeling and phosphate oxygen isotope results allowed a clear distinction of the fraction of inorganic P (Pi) derived from glyphosate, about half of which was then rapidly taken up and recycled by soil microorganisms. Our results provide the first evidence of the preferential utilization of glyphosate-derived Piby microorganisms in the soil-water system. The rapid cycling of Piderived from this disregarded source has important implications on nutrient management as well as water quality.