Behaviors Of Novel Oxime Pesticide HNPC-A9908 In Environments

Novel insecticide Liuwomi, code number: HNPC-A9908, chemical name: O-(3-phenoxybenzyl)- 2-methylthio-1-(4-chlorophenyl) propyl ketone oxime, is a novel oxime insecticide which is discovered and developed by Hunan Branch of the National Pesticide R & D South Center. It can be used to control effectively various pest insects such as imported cabbageworm Pieris rapae, Rice leafhopper Nephotettix cincticeps, oriental armyworm Mythimna separata, tea tussock moth Euproctis pseudoconspersa, tea geometer Ectropis oblique, tea green leafhopper Empoasca spp, etc on vegetable, rice, tea and other crops.Very little information is available about chemical behaviors and ecological effects of insecticide liuwomi and its relative compounds in the environments because of novelty of the insecticide. Therefore, It is very emergent and important to comprehensively understand persistence, movement and transformation of novel pesticide liuwomi and its potential hazards in ecological environments before it launches into the market in order to assess correctly the environmental safety of the insecticide liuwomi. Residue dissipation, adsorption in soils, hydrolysis, photolysis of novel pesticide liuwomi in environments and its interactions with green algae have been studied in the dissertation since 2001. According to the research contents, the dissertation was divided into eight parts. The main conclusions obtained were listed as follows:In the first part the basic concepts, theories and current advances were reviewed briefly on adsorption, hydrolysis, photodecomposition, biodegradation and interactions of pesticide with green alga, and discovery of novel oxime insecticide liuwomi and its applications in control of pest insects was introduced concisely.In the second part the residue of novel insecticide liuwomi in Chinese cabbages and soils were investigated. The results showed: (1) a method for determining residue of the insecticide liuwomi in soil and water by high performance liquid chromatography (HPLC) was developed. The insecticide liuwomi residue in soil was extracted with methanol, partitioned with dichloromethane/sodium chloride solution and cleaned up by the column filled with acidic aluminum oxide and silica gel, but the residue in water was directly extracted with dichloromethane. The quantification of the insecticide liuwomi residue was established by HPLC with a C18 column, a mixture of methanol plus water (95/5 ,V/V) as mobile phase, with detection of UV wavelength at 254 nm. The result showed that the average recovery for the soil andwater samples spiked at the concentration of 0.1, 1 and 5 mg/L was in a range of 94.68%~103.7% and 96.5%~100.03%, respectively. The minimum detection limit for soil and water was 0.01mg/kg and 0.001 mg/L, respectively. (2) The average initial deposits of 10% liuwomi EW in the Chinese cabbages and soil at the application rate of 120 g ai/hm2 were 2.5412 mg/kg and 0.1986 mg/kg, respectively, and then residues in the Chinese cabbages and soil decreased gradually as time went on. The residue fell below detectable limit within 21d.The half-life of 10% liuwomi EW in Chinese cabbages and soil was 1.94d and 4.96d, respectively. At the rate of 120 g ai/hm2, the final residue of liuwomi in the Chinese cabbages was 0.2182 mg/kg~0.2749 mg/kg and 0.0257 mg/kg~0.0299 mg/kg, respectively, at the interval time of 3d and 7d after liuwomi was sprayed on the Chinese cabbages two or three times, and at the rate of 240 g a.i./kg, the final residue of liuwomi in the Chinese cabbages was 0.697 mg/kg~0.7039 mg/kg and 0.3128 mg/kg~0.3357 mg/kg, respectively, suggesting thatliuwomi belong to a low residue and degradable insecticide.In the third part the adsorption and its mechanisms of insecticide liuwomi on soils were studied in the laboratory. Results exhibited: (1) Adsorption isoterms of liuwomi on the soils such as Yongzhou heavy clay, Changshun clay, Tianshui clay, Shenyang silt clay and Changsha silt clay were S-type showing high adsorption amount at the low concentration of liuwomi, and can be described by Freundlic...