毒死蜱在韭菜中的残留动态研究

韭菜是中国消费者比较喜爱的一种蔬菜,其食用安全性关系到消费者的身体健康.毒死蜱在韭菜生产中经常采用叶面喷洒和灌根方式进行害虫防治.采用气相色谱法(GC-NPD)进行毒死蜱残留测定,研究了毒死蜱在韭菜生产中灌根和叶面喷洒时的残留动态.结果表明,在推荐用量和加倍用量灌根处理条件下,毒死蜱的半衰期分别为3.81 d和3 42 d;在推荐用量和加倍用量叶面喷洒处理条件下,毒死蜱的半衰期分别为2.42 d和2.38 d.不同的用药方式对韭菜中毒死蜱残留量的影响存在差异.若严格按照良好农业操作(GAP)生产,可以符合无公害韭菜中最大残留限量标准的要求.

Residual dynamics of chlorpyrifos in Allium tuberosum

This paper is concerned with a study report on the pesticide residue left over by the Allium tuberosum.As is known,Allium tuberosum is a popular kind of vegetable in China,and maggot in Allium tuberosum is one of the main pests in the process of its growth and cultivation.Generally speaking,maggots can be controlled and killed by chlorpyrifos through foliage spray and root irrigation along with watering.However,there exists a degradation trend with the use of chlorpyrifos in Allium tuberosum,which is one of the central issues for the recent study and was detected by using GC-NPD.The results of our study have shown that the residual degradation rate of chlorpyrifos in the vegetable can be different with the different methods of chlorpyrifos application.Based on the recommended methods of one-dose and double-dose application,the half-life of chlorpyrifos residue degeneration period in Allium tuberosum is 3.81 d and 3.42 d respectively under the root zone pesticide application through irrigation.However,it becomes 2.42 d and 2.38 d after application through foliage spray.Thus,it can be concluded that the chlorpyrifos residue in the soil of the root zone may be positively correlated with the residue lasting time in Allium tuberosum.That is to say,it means that high residue in the soil with high residue absorbed by Allium tuberosum.If Allium tuberosum can be produced in close conformity with the GAP,the residue in it can be made not to exceed the MRL(1.0 mg/kg),which is safe for consumers.