Dissipation Behavior of Fenvalerate Residue in Made Tea during Brewing Process and Its Maximum Residues Levels Evaluation

Fenvalerate was sprayed in a growing equably tea farm.The green shoots was harvested from treated plots at 2 h and 1 h,2 h,3 h,5 h,7 h,9 h,14 h,21 days after the treatment,and manufactured into green tea.The concentration of fenvalerate-trans and fenvalerate-cis in made tea、its infusion and infused leaves were determined by gas chromatography.And dissipation behavior of fenvalerate residue in made tea and its infusion was investigated.Results indicated that the residue level of fenvalerate-trans and fenvalerate-cis in made tea decreased gradually while the plucking interval increased.The residue of fenvalerate-trans and fenvalerate-cis in made tea from 9.40 mg/kg and 17.51 mg/kg at 2 h after the treatment decreased to 1.07 mg/kg and 1.53 mg/kg at 21 days at the dose of 20 mL/667 m2,and from 20.37 mg/kg and 38.67 mg/kg at 2 h decreased to 1.94 mg/kg and 3.06 mg/kg at 21 days at the dose of 40 mL/667 m2.The concentration of fenvalerate residue in tea infusion(y)show quadratic function with that in made tea(x).Quadratic equation is y=-0.0007x2+0.0242x(fenvalerate-trans) and y =-0.0002x2+0.0114x(fenvalerate-cis).According to fenvalerate MRL(maximum residues levels) in tea in China,the percentage of fenvalerate residues intake amounts possibly by drinking tea infusion comparing with ADI is 0.049 %,which is sufficient for protecting human health.And according to fenvalerate MRL in tea in EU,the percentage of fenvalerate residues intake amounts comparing with ADI(acceptable daily intake),is 0.0019 %,which is on 10-5 level and near the risk control level(10-6)of threshold effect chemical.