Detection and risk assessment of cypermethrin residue in tea and tea infusion in Guizhou

Gas chromatography was used to determine the residue level of cypermethrin in tea samples.Determination of cypermethrin residues was investigated to evaluate the tea samples to be sold in Guizhou Province.An orthogonal field experiment was designed to study the factors that influence the extraction rate of cypermethrin.The results showed that the average and highest cypermethrin residue of the teas on Guizhou Province market was 0.919 mg/kg and 1.52 mg/kg which were much lower than the maximum residue limit (MRL) of 20 mg/kg for cypermethrin.The result of the orthogonal experiment showed that the times and time of soaking were the main factors affecting the extraction rate of cypermethrin.The highest extraction rate of cypermethrin was 5.76% for an average person,which suggested a maximum daily intake of 1.5×10-2 mg.The safety coefficient ( K ) was 200,acceptable daily intake (ADI) 0.05 mg/kg bw for cypermethrin,average weight 60 kg.