几种常用农药在菠菜中的残留动态研究

在露地栽培条件下,研究了氯氰菊酯、氰戊菊酯、毒死蜱和百菌清在菠菜生产中的残留降解动态.试验结果表明,不同农药在菠菜体内的降解速度有很大差异,其残留量随用药后时间的延长而减少.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3.95 d和4.61 d,氯氰菊酯的半衰期分别为5.03 d和5.88 d,氰戊菊酯的半衰期分别为5.26 d和7.22 d,百菌清的半衰期分别为2.63 d和3.39 d.在试验的4种农药中,氰戊菊酯的半衰期最长,百菌清的半衰期最短.因此,在菠菜生产中使用农药时,应充分考虑所用农药的半衰期,严格掌握安全间隔期,确保生产的菠菜达到无公害菠菜的质量标准要求.

Research on residue dynamics laden in some commonly used pesticides in spinach

The present article intends to report its author's investigation of the residual dynamics left over in spinach, such as those of cypermethrin, fenvalerate, chlorpyrifos and chlorothalonil in in the open-field conditions according to the state standard vegetable-growing regulations. For our research purpose, we have analyzed residues of four pesticides left over by GC (Gas Chromatograph) with ECD or NPD, with the investigation results showing that the degradation rates in autumn spinach prove noticeably different with the above-said pesticides. However, the same trend can be observed with the results that their residues would have been decreasing over time after spraying. Based on the recommended dose and double dose, the half-life of chlorpyrifos residue in the spinach was 3.95 d and 4.61 d, 5.03 d and 5.88 d for cypermethrin, 5.26 d and 7.22 d for fenvalerate, 2.63 d and 3.39 d for chlorothalonil, respectively. Among the four kinds of pesticides observed, the half-life of cypermethrin is longest, while that of chlorothalonil is shortest. Therefore, when using pesticides in spinach growing, it is essential to consider the half-life of pesticides to be used, which should be in conformity with the recommended pre-harvest interval (PHI) prior to the harvest time strictly, in order to meet the requirements of the qualitative safety standard with the least pesticide pollution to the spinach.