土壤中甲基乙磺隆的淋溶与降解

Leaching and degradation of ethametsulfuron-methyl in soil.

作者信息

Si Youbin, Wang Shenqiang, Zhou Jing, Hua Rimao, Zhou Dongmei

机构信息

College of Resource and Environmental Science, Anhui Agricultural University, Hefei 230036, China.

出版信息

Chemosphere. 2005 Jul;60(5):601-9. doi: 10.1016/j.chemosphere.2005.01.051.

DOI:10.1016/j.chemosphere.2005.01.051

PMID:15963798

Abstract

Leaching and degradation of the herbicide ethametsulfuron-methyl[methyl 2-[(4-ethoxy-6-methylamino-1,3,5-triazine-2-yl)carbamoylsulfamoyl]benzoate] in three soils were investigated under laboratory conditions. Ethametsulfuron-methyl was mobile on soils when tested using non-aged and aged soil columns; this mobility agreed reasonably well with Freundlich soil isotherm constants. It was found that ethametsulfuron-methyl was more mobile in alkaline sandy Vertisol soil and neutral loamy Alfisol soil than in acidic clayey Red soil. Degradation of ethametsulfuron-methyl in soils was pH-dependent; calculated half-life (t(1/2)) values ranged from 13 to 67 days. Ethametsulfuron-methyl was more persistent in neutral or weakly basic than in acidic soil. Five soil metabolites were isolated and identified by LC/MS/MS analysis. The degradation pathways included the cleavage of the sulfonylurea bridge, N- and O-dealkylation, and triazine ring opening.

摘要

在实验室条件下，研究了除草剂甲基乙磺隆[2-[(4-乙氧基-6-甲氨基-1,3,5-三嗪-2-基)氨基甲酰基磺酰基]苯甲酸甲酯]在三种土壤中的淋溶和降解情况。使用未老化和老化的土柱进行测试时，甲基乙磺隆在土壤中具有移动性；这种移动性与弗伦德利希土壤等温线常数相当吻合。结果发现，甲基乙磺隆在碱性砂质变性土和中性壤质淋溶土中比在酸性黏质红壤中更具移动性。甲基乙磺隆在土壤中的降解取决于pH值；计算出的半衰期（t(1/2)）值在13至67天之间。甲基乙磺隆在中性或弱碱性土壤中比在酸性土壤中更持久。通过LC/MS/MS分析分离并鉴定了五种土壤代谢物。降解途径包括磺酰脲桥的断裂、N-和O-脱烷基化以及三嗪环的开环。