农田尾菜发酵过程中农药残留变化特征

基于尾菜中存在农药残留的现状,以设施农业尾菜黄瓜秧为研究对象,采用气相色谱法和超高效液相色谱-串联质谱法检测了尾菜黄瓜秧在静态好氧发酵过程中多菌灵、吡虫啉、哒螨灵等50种农药残留的动态变化,并分析发酵重要影响因子堆高对农药残留消解的影响。结果表明:在尾菜黄瓜秧中共检测出腐霉利、多菌灵、嘧菌酯、苯醚甲环唑、烯酰吗啉、虫螨腈、吡虫啉、啶虫脒和哒螨灵9种农药残留,其中多菌灵平均残留量最高,达11.2 mg/kg,其他8种农药平均残留量在0.042~0.89 mg/kg之间。在发酵的24 d中,不同堆高条件下9种农药的消解规律均符合一级反应动力学方程,但不同农药半衰期差异较大,其中吡虫啉的平均半衰期最长,为28.9 d,多菌灵的平均半衰期最短,为10.2 d;不同堆高处理中农药的消解速率也有差异,总体上在2.5 m堆高下各农药的消解率最高、半衰期最短。本研究结果可为尾菜发酵参数优化、农业废弃物的高效资源化利用以及研发基于尾菜发酵产物的有机蔬菜专用有机肥提供理论支撑。

Dissipation of pesticides residues during vegetable waste fermentation

The residue and dissipation of 50 pesticides such as carbendazim, imidacloprid, and pyridaben during cucumber vines fermentation were determined by gas chromatography and ultra high-performance liquid chromatography-tandem mass spectrometry in view of the pesticide residue conditions of vegetable waste. The effect of compost heights on pesticide degradation was evaluated. The results shows that: nine pesticides, including procymidone, carbendazim, azoxystrobin, difenoconazole, diemthomorph, chlorfenapyr, imidacloprid, acetamiprid and pyridaben, were detected in the waste of vegetable.  Carbendazim was found with highest average residue concentration of 11.2 mg/kg, and those of other pesticides ranged from 0.05 to 0.89 mg/kg. During the fermentation processes (24 days) under conditions with various compost heights, the concentrations of 9 pesticides degraded gradually and results of the dissipation of pesticides residues fitted to first-order kinetics. However, the half-lives varied between different pesticides. The longest half-life of 28.9 d was found in the case of imidacloprid. And the shortest half-life of 10.2 d  was found in the case of carbendazim. The degradation of pesticides also varied with different compost heights. In general, the highest degradation rate and the shortest half-life were obtained using 2.5 m compost height. The results of this study provide insights into the parameter optimization and quality control during the vegetable waste fermentation process and a new strategy for the high efficiency utilization of agricultural wastes for the fertilizer preparation in the organic vegetable production.