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Residue Dynamics of Novel Insect IPP and Environment Behaviors

Author: WangZuo
Tutor: YangZuo
School: Harbin Institute of Technology
Course: Of Food Science
Keywords: IPP residue analytical methods plant metabolism soil degradation water environment degradation
CLC: TQ453.2
Type: Master's thesis
Year: 2012
Downloads: 76
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Abstract

Paichongding is a new kind of neonicotinoid insecticide. In order toproperly evaluate the environmental behavior of IPP in wheat, water and soil,and the degradation dynamic, law of metabolism and its influencing factors. Theresearch focused on four parts: the first part is detection methods; the second isdegradation dynamic in wheat and the effect on physiology and biochemistry ofwheat; the third is dissipation, absorption and migrate in soils, and the fourth isphotolysis and hydrolysis in water. They are independent of each other, but alsoclosely linked to provide a scientific basis for the establishment of theevaluation criteria for safety and the registration of the IPP.（1） A method was developed for determination of IPP residue in wheat, soiland soil by High Performance Liquid Chromatography coupled with tandemdiode array detector （HPLC-DAD）. The residues of7neonicotinoid pesticides ingrains （Brown rice, Millet, Oat and Maize） were purified by dispersive solidphase extraction （DSPE） and dispersive liquid-liquid microextraction （DLLME）.The results showed that this method was convenient and rapid. Each insecticidesin the range of0.02-4.50μg·mL^-1has a good linear realationship with R2isgreater than0.99. The spiked recoveries in four grains fell within76^-123%. Therelative standard deviation （RSD） was between0.9%and12.6%. Low limits ofdetection (0.002to0.005mg·kg^-1) and quantification (0.007to0.018mg·kg^-1)were readily achieved with this method for all tested pesticides. In addition, IPPin the range of0.05^-10.00μg·mL^-1has a good linear realationship, R2is0.9999,the spiked recoveries in wheat fell within92.30-97.94%. The RSD was between2.55%and3.20%. Low limits of detection and quantification were0.018mg·kg^-1and0.030mg·kg^-1, respectively. Furthermore, the spiked recoveries in soil fell within92.84-95.19%. The RSD was between2.02%and5.83%. Low limits ofdetection and quantification were0.008mg·kg^-1and0.020mg·kg^-1, respectively.At last, the spiked recoveries in water fell within93.56-95.80%. The RSD wasbetween5.42%and8.20%. Low limits of detection and quantification were0.008mg·kg^-1and0.020mg·kg^-1, respectively.（2） The degradation dynamic in wheat and the effect on physiology andbiochemistry of wheat. The degradation residual dynamics in wheat werestudied at different functional doses. The results show that degradation residualdynamics could be described by the first order kinetic equation with the range ofhalf-life was0.92-2.19d, and the degradation rate and dose concentration werepositively correlated. The oxidative damage of wheat was caused by IPP afterspraying, and a series of anti-oxidation was stetted to defense this damage, suchas change in SOD, CAT, POD and MDA. Cropper induced antioxidant reactionsof wheat were investigated in both time and concentration-dependent manners.As the results show that all the functional doses of the IPP caused oxidativedamage to the cell membrane of wheat at the earlier time （0-2d）, leading to lipidperoxidation （MDA） and repaired greatly at the later treatment （2-9d）.Superoxide dismutase （SOD） is the first line of defense antioxidive system,showing a particularly important role. In addition, a number of other antioxidantenzyme systems and non-enzymatic substances also reflect the importantsynergies, such as catalase （CAT）, protein and so on. In conclusion, IPP has anobvious effect on the physiology and biochemistry of wheat.（3） The environmental behavior and metabolism of IPP in soil. Thedissipation, absorption and migration behaviors of IPP in soils and itsinfluencing factors were studied. The results show that degradation residualdynamics in soils could be described by the first order kinetic equation with the range of half-life was1.14-8.04d. The degradation half-lives and soil pH valueswere positively correlated, while cation exchange capacity （CEC）, organicmatter （OC） and clay content were negative, and soil moisture content had nosignificant effect on its. Additionaly, the adsorption behaviors of three soilswere fitted greatly to Freundlich equation. Loamy soil was chemical adsorptionand irreversible. In contrast, the sand and clay soils were physical adsorptionand reversible. IR of IPP, humic acid and kaolin clay were studied with infraredanalysis technology, and compared with IR of IPP-humic acid and IPP-kaolin,respectively to deduce the adsorption mechanism of IPP in soils. The leachingcharacters of IPP were studied, and their migration behavior and adsorptionbehavior were negatively correlated. The mobility levels of the three soils weremedium.（4） The environmental behavior and metabolism of IPP in water. Thephotolysis and hydrolysis of IPP in water were studied, respectively. The resultswere shown as below: On one hand, the photolysis of IPP in water had twoaspects, including direct photolysis and indirect photolysis. The light source andthe initial concentration of IPP solution play an important role in directphotolysis with the range of half-life was3.98-5.25h, and the greater the initialconcentration, the slower rate of degradation; during the indirect photolysis,Acetone （1.34h）, Hydrogen peroxide （1.89h） and Nitrate （2.68h） showedsignificant sensitization while Hexane （57.74h） and Humic acids （91.83h）showed a significant effect on quenching. On the other hand, pH is the dominantfactor in the hydrolysis, the half life was29.07d when pH11and1.85d whenpH12. Some chemical compounds were added into an aqueous solution of IPPsuch as humic acid, tween80and Metal ions Cu and all of them improved thehydrolysis process. At last, In this paper, groundwater, rainwater, sewage and river water were selected as the main natural water bodies, in order to simulateits actual hydrolysis process, the order of the rate degradation of the four waterbodies of was sewage> river water> rain> groundwater. With regard of the basicecological parameters of the water, the salinity of the water body and itsdegradation half-life were significantly negatively correlated. The chemicalstructure of photolysis products and hydrolysis products were studied byLC-MS/MS, and then the possible photolysis pathways and hydrolysis pathwaywas presumed.

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