覆膜栽培方式下毒死蜱、丙溴磷和三唑磷在金桔和土壤中的消解动态

Degradation of Chlorpyrifos,Profenofos and Triazophos in Plastic-film Mulching Kumquat and Soil

【目的】了解覆膜栽培方式下,毒死蜱、丙溴磷和三唑磷在金桔果实和土壤中的消解动态及残留规律,为金桔果品安全生产提供参考依据。【方法】采用气相色谱分析技术,对田间试验采收的样品进行农药残留检测。【结果】在金桔和土壤中添加毒死蜱、丙溴磷和三唑磷0. 05~1. 00 mg·kg-1,其平均回收率为84. 6%~105. 8%,相对标准偏差(RSD)为1. 2%~4. 9%。3种农药在金桔和土壤中的定量限(LOQ)均为0. 020 mg·kg-1。毒死蜱、丙溴磷和三唑磷在金桔及土壤中的残留消解动态均符合一级动力学方程。毒死蜱在金桔和土壤中的半衰期分别为5. 1和5. 2 d;丙溴磷在金桔和土壤中的半衰期分别为27. 1和27. 0 d,三唑磷在金桔和土壤中的半衰期分别为27. 7和14. 5 d。按照推荐剂量和2倍推荐剂量对金桔和土壤施用毒死蜱、丙溴磷和三唑磷,距第2次施药7 d后,金桔中的毒死蜱残留量已经低于我国国家标准规定的最大残留量,80 d后金桔和土壤中均未检测出毒死蜱残留;距第2次施药80 d后,金桔中三唑磷残留量低于最大残留量,100 d后未检出;而100 d后仍能检测出丙溴磷在金桔和土壤中的残留,但残留值已经降低至最大残留量以下。【结论】毒死蜱、丙溴磷和三唑磷在金桔中属于易降解农药,安全采收间隔期建议为100 d。

[ Objective] To provide references for the safety production of kumquat fruit, the degradation and residue of chlorpyrifos, profenolos and triazophos in plastic-fihn mulching kumquat and soil were studied. [ Method] The pesticide residues in field experiment samples were detected by gas chromatography. [ Result] The results indicated that average recovery rate of three pesticides at 0.05 to 1.00 mg · kg ^-1 spiked levels ranged from 84.6 % to 105.8 %, with relative standard deviations （RSD） of 1.2 % to 4.9 %. The limits of quantification （LOD） were 0. 020 mg ·kg^- 1 in kumquat fruit and soil. The degradation of chloryrifos, profenofos and triazophos in kumquat fruit and soil samples proved to follow the first order kinetic quation. The half-life of chlorpyrifos in kumquat fruit and soil were 5.1 and 5.2 days, pro- fenofos were 27.1 and 27.0 days, triazophos were 27.7 and 14.5 days, respectively. Chlorpyrifos, profenofos and triazophos were applied to kumquat fruit and soil according to the reconunended and double reconunended dose. 7 days after the second application, the residue of chlorpyrifos in fruit was lower than the maximum specified in China national standard. No chlorpyrifos residue could be detected in both after 80 days. The residue of triazophos in fruit was less than the maximum residue at 80 days after the second application, no residue at 100 days. The residue of profenofos in fruit and soil could still be detected after 100 days, but the value was below to the maxinum residue. [ Conclusion] Chlorpyrifos, profenofosand triazophos were degradable pesticides in kumquat, and the safe harvesting interval was 100 days.