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作 者 ：陈敏, 贺宇鹏, 杨亚天, 叶庆富, 汪海燕

期 刊 ：核农学报 2016年 30卷 5期 页码：949-956

关键词：环氧虫啶；对映体选择性；结合残留；降解；半衰期；

Keywords:cycloxaprid, enantioselectivity, bound residue, degradation, half life,

摘 要 ：为明确环氧虫啶异构体在土壤环境中的迁移转化及代谢降解规律,本试验以¹⁴C标记外消旋环氧虫啶为示踪剂,综合运用核素示踪与高效液相色谱分离技术,研究了好氧条件下环氧虫啶在3种土壤中的快速降解动态规律,并分析了其形成结合残留和母体降解可能的对映体选择特性。结果表明,好氧条件下环氧虫啶在整个培养期(120 h)内,未发现其2种对映异构体的结合残留形成和母体降解具有手性差异。环氧虫啶在3种土壤中均迅速形成结合残留,其结合残留量由高到低依次为中性黄松土、碱性滨海盐土、酸性红砂土。环氧虫啶属于易降解农药,好氧条件下环氧虫啶在3种土壤中的降解动态显著符合一级动力学方程,其降解速率由快到慢依次为酸性红砂土(半衰期为23.10 h)、中性黄松土(半衰期为53.32 h)、碱性滨海盐土(半衰期为77.02 h)。数据分析还表明,土壤pH对环氧虫啶的降解速率影响最大。本研究为环氧虫啶的登记注册奠定了基础,为环氧虫啶的正确、合理使用提供了科学依据。

Abstract:In order to explore the transformation and degradation of cycloxaprid (CYC) in aerobic soil, ¹⁴C-labeled racemic CYC was used to investigate the rapid degradation of CYC in soils under aerobic conditions by liquid scintillation measurement technology and high-performance liquid chromatography coupled with chiral liquid chromatography column, and to explore the possible enantioselectivity in bound residue formation and the degradation of CYC isomers. Results showed that no enantioselectivity was found in the formation of bound residue and the degradation of CYC isomers in aerobic soils during the whole incubation. Bound residue formed rapidly in the three soils and followed the order of yellow loamy soil>coastal saline soil>red clay soil. CYC is classified as an easily degraded insecticide and its degradation dynamics fit well to the first-order kinetic equation. CYC half-lives in yellow loamy soil, coastal saline soil, and red clay soil were 53.32 h, 77.02 h, and 23.10 h, respectively. Further statistical analysis on the correlation between the half-lives and soil physicochemical properties showed that soil pH was one of the most influential factors. This study provides useful basis for the formal registration and the scientific use of CYC.

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