Residue Behavior And Dietary Risk Assessment Of Azoxystrobin On Eggplant

To clarify the safety of applying 25%azoxystrobin?WDG?to eggplant for consumers,the field trial was conducted in 2017 in six provinces of Hunan,Shandong,Henan,Anhui,Yunnan and Guangxi.The dissipation dynamic of azoxystrobin in eggplants in Hunan,Anhui and the terminal residue of azoxystrobin in six provinces in eggplant were studied,and the dietary risk assessment of azoxystrobin on eggplants based on experimental data was also evaluated.The result of the study has important guidance and reference significance for the detection of azoxystrobin residue in vegetables and its safe application in the field,as well as the formulation of pesticide residue standards and the construction of food safety supervision system.The main research contents and results as follows:?1?Spike recovery experimentsEggplant samples were extracted with acetonitrile and purified by an amino-phasesolid-phaseextractioncolumn.Ultraperformanceliquid chromatography-mass spectrometry?LC-MS/MS?was used to detect.Recovery studies were performed at three fortification levels of 0.01,0.1,1 mg/kg in eggplant matrix with the average recoveries ranging between97.0%±0.9%¹02.0%±1.9%and the relative standard deviation?RSD?is 2.3%⁸.2%.The limits of detection?LOD?of azoxystrobin is 0.001 ng,and the limits of quantification?LOQ?is 0.01 mg/kg.?2?Dissipation dynamic experimentsThe dissipation dynamic of azoxystrobin in eggplant samples in Anhui followed the first-order kinetic equation,the equation of dissipation dynamic is C_T=0.1758e^-0.128T.Based on first-order kinetics,the half life period of azoxystrobin at the experimental site in Anhui was 5.6 d.?3?Terminal residue experimentsApplied the azoxystrobin to eggplant according to the recommended dose of 270g ai/hm² and 1.5 times the recommended dose of 405 g ai/hm²,each dose was applied2 times and 3 times,respectively,the interval between two applications was 7days,and the eggplant samples were collected after the last application 5,7 and 10days,the terminal residue of azoxystrobin was between<0.01¹.61 mg/kg.?4?Dietary risk assessmentAssessed the dietary risk of azoxystrobin in eggplant based on experimental data,the results showed that the national estimated daily intake?NEDI?of the azoxystrobin was between 0.11 to 0.41?g·kg^-1 bw·d for all age groups from 2 to>70years of age.The dietary risk is 0.05%⁰.21%,which is far less than 100%,it can be neglected.,This shows that it is safety to spray azoxystrobin during the cultivation period of eggplant under the scientific application and scientific management.With reference to the MRL values in foreign for azoxystrobin on eggplant and the establishment of MRL values for azoxystrobin in other solanaceous crops in China,3 mg/kg was prepared as the MRL value of azoxystrobin on eggplants.which was refered to calculate the protection level?CPL?for consumers on eggplant,and the theoretical maximum daily intake?TMDI?for all age groups is 13.64²9.60?g·kg^-1bw·d,and the protection level of MRL to consumers is between 6.76 and 14.66,greater than 1,indicating that 3 mg/kg as the MRL value of azoxystrobin on eggplant can protect consumers of all age groups in China in long-term dietary exposure risk.,?5?Suggestion and recommendationSuggestion that apply 25%azoxystrobin?WDG?to eggplant,the spraying dose no more than 270 g ai/hm²,2 to 3 times per growth period,the interval between two applications is 7 days,and the safety interval is 5 days;recommending the maximum residue limit of azoxystrobin in eggplant is 3 mg/kg.