Microbial Degradation And Metabolism Of F1050 In Soil

An analytical method was established for determining the residue of F1050 (N-(2-methyl-5-chlorophenyl)-2, 4-dinitryl-6-trifluoromethyl-aniline), a new compound of acaricide, by capillary Gas Chromotography with the electron-capture detecter (ECD) under the condition optimized. F1050 was separated efficiently from impurity and responded in very high sensitivity on ECD. The limit of detection for F1050 was 5. 26 X 10 -14 g. It was applicable to determine the residue of the acaricide in soil and orange, and satisfied to meet the requirement of fortified recovery.It was confirmed that micro-organisms in soil played a very important role to decompose the acaricide with the results of degradation for F1050 in three types of soil (sandy loam, clay loam and loam sand). The half-lives of F1050 with a level of 50mg/kg in three types of soil were 30. 27, 43. 59 and 21. 13 days, comparing with it in three types of sterilized soil, 161.20, 223. 60 and 108. 30 days, respectively.It was observed that micro-organisms in three types of soil treated with the acaricide at the range of 2-50mg/kg grew greatly different from those in control. The results showed that Bacteria, such as Bacillus was grown most fastest, and then Fungi were increased appreciably, but Actinomyces was seemed to be none-influence by F1050.Three dominant strains of Bacteria in soil were obtained by the screening experiments, which were ZJU. 02 (Bacillus megaterium), ZJU. 04 (Bacillus sphaericus) and ZJU. 05 (Bacillus cereus). The results of microbial degradation of the acaricide showed that ZJU. 02, ZJU. 04 and ZJU. 05 had a spetial ability to degrade the chemical from those Bacteria tested in culture media added a series volumes (10% in total volume) of Bacteria suspensionwhile the concentration of the acaricide at 50mg/kg in the media. And the results showed that ZJU. 02, ZJU. 04 and ZJU. 05 doesn't promote obviously the degradation process of F1050 in soil (20g) after added 5mL of the Bacteria suspension (OD460i=0. 40), respectively.In the pure liquid culture media, three metabolites were obtained, N-(2-methyl-5-chlorophenyl)-2-amido-4-nitryl-6-trifluorometyl-aniline, N-(2-methyl-5-chlorophenyl)-2-nitryl-4-amido-6-trifluoromethyl-aniline and 2, 4-dinitryl-6-trifluoromethyl-aniline. It could be suggested that deoxidize and hydrolysis reaction were the main ways for degradation of F1050 by soil micro-organisms.The degradation trials of dynamic for F1050 in orange field indicated that F1050 was degraded quickly in soil and orange, and its half-lives were 9. 82 days (in soil) and 4. 39 days (in orange). There was no F1050 in orange after harvested. It could be suggested that there be safety or no obvious toxicity to human health while orange be consumed as a food for people if the acaricide be applied by the way of the field trials. The residue of F1050 in soil and pericarp indicated that there were influence with the spraying concentration and spraying amount of the acaricide.