氟啶虫酰胺和联苯菊酯在桃上的残留行为及膳食摄入风险评估

Residues and dietary intake risk assessment of flonicamid and bifenthrin in peach

【目的】研究氟啶虫酰胺和联苯菊酯在桃上的残留行为,评估两种农药的长期膳食摄入慢性风险,推荐两种农药在桃上的最大残留限量值(MRL),计算推荐值和国际标准值对中国普通消费者的保护水平。【方法】建立乙酸乙酯QuEChERS-GC-ECD同时测定桃中氟啶虫酰胺和联苯菊酯残留量的分析方法,分析两种农药在桃中的残留消解及最终残留量,进行膳食摄入风险评估,计算慢性风险商(RQc)及MRL对中国普通消费者的保护水平(CPLc)。【结果】氟啶虫酰胺和联苯菊酯在桃中的消解速率符合一级反应动力学方程,半衰期分别为2.5~5.6 d、1.6~6.7 d,属易消解农药。推荐采收间隔期(PHI)为14 d,普通人群对氟啶虫酰胺和联苯菊酯的RQc分别为18.0%、45.1%,桃的贡献率分别为0.09%、0.2%。桃上氟啶虫酰胺和联苯菊酯的美国MRL对中国普通消费者的保护水平分别为5.37、2.06,试验推荐MRL的保护水平分别为5.53、2.19。【结论】采用改进的乙酸乙酯QuEChES-GC-ECD方法,可简便、快捷地实现氟啶虫酰胺和联苯菊酯的同时检测。按照推荐PHI,两种农药的长期膳食摄入慢性风险均处于可接受水平。推荐MRL严于美国MRL,但二者对中国普通消费者慢性膳食风险起到的保护水平较为一致。

【Objective】To provide the basic data for rational use of flonicamid and bifenthrin,the residual characteristic of the two pesticides used in peach were studied,and the chronic risk assessment of long-term dietary intake of the two pesticides were evaluated.The maximum residue limits(MRLs)of flonicamid and bifenthrin in peach were recommended,and the comparisons with the international MRLs were analyzed.【Methods】An analytical method was established to simultaneously detect the residues of flonicamid and bifenthrin in peach.The samples were extracted with ethyl acetate,purified with QuEChERS method,detected with gas chromatography-electron capture detector(GC-ECD),and quantified with external standard method.The digestion patterns and the final residues of flonicamid and bifenthrin in peach were analyzed.The national estimated daily intake(NEDI)or theoretical maximum daily intake(TMDI)were calculated by using the supervised trial median residue(STMR)or maximum residual limit(MRL),and the chronic risk quotient(RQc)was calculated according to the acceptable daily intake(ADI).The pre-harvest interval(PHI)and MRLs for the two pesticides were recommended.The protection level(CPLc)of recommended MRLs and international standards for the two pesticides in peach were evaluated separately and compared【.Results】At the spiked level of 0.01,0.1 and 1.0mg·kg^^-1,the recovery rate of flonicamid ranged from 86%to 104%,and the relative standard deviation(RSD)ranged from 1.5%to 5.5%.At the same spiked concentrations,the recovery rate of bifenthrin was between 82%and 92%,and the RSD was between 1.9%and 2.2%.The limits of quantitation(LOQ)of both pesticides in peach were 0.01 mg·kg^^-1.The field trials for final residue were conducted in eight provinces in 2018,including Shandong,Hebei,Henan,Zhejiang,Shanxi,Sichuan,Liaoning and Hubei provinces.The dynamic digestion experiments were carried out in Liaoning,Hubei,Hebei and Zhejiang provinces.The degradation patterns of flonicamid and bifenthrin in peach accorded with the first-order reaction kinetic equation,and the half-life was 2.5-5.6 d and 1.6-6.7 d,respectively,proving that the two pesticides are easily digested.The original deposition amounts were slightly different in different regions,and the experimental site in Liaoning province was relatively low.The high single fruit weight of peach,which was 2-4 times of that of other varieties on average was speculated.The application of pesticides in the fruit expansion stage had a greater dilution effect on pesticides compared with other varieties.15%bifenthrin·flufenthrin suspension concentrate(SC)was applied twice in accordance with the highest recommended dosage(37.5 mg·kg^^-1)in peach trees.At 14 days after the second application,the final residue range of flonicamid was from less than 0.01 mg·kg^^-1 to 0.033 mg·kg^^-1 with the STMR of 0.015 mg·kg^^-1,and the final residue range of bifenthrin was from less than 0.01 mg·kg^^-1 to 0.029 mg·kg^^-1 with the STMR of 0.012 mg·kg^^-1.At 21 days after the second application,the final residue range of flonicamid was from less than 0.01 mg·kg^^-1 to 0.024 mg·kg^^-1,and the final residue range of bifenthrin was from less than 0.01 mg·kg^^-1 to 0.025 mg·kg^^-1,which both with the STMR of lower than LOQ in the analyzed samples.The final residual quantity decreased with the extension of sampling interval.PHI was recommended to be 14 d.Flonicamid was registered on seven edible crops such as rice,cucumber,potato,apple and tea,while bifenthrin was registered on twelve edible crops such as wheat,tomato,cucumber,apple,cotton,sugar cane and tea.According to GB 2763,the ADI values of flonicamid and bifenthrin are 0.07 mg·kg^^-1 bw and 0.01 mg·kg^^-1 bw,respectively.The dietary intake risk assessment showed that the chronic risk quotient of long-term dietary intake for the general population to flonicamid and bifenthrin was 18.0%and 45.1%,respectively,to which,the contribution of peach was 0.09%and 0.2%,respectively.The results suggested that flonicamid and bifenthrin generally does not pose an unacceptable chronic risk of long-term dietary intake on the general population,and peaches were only a small percentage of the total dietary intake risk.According to HR,the MRL values of the two pesticides on peaches were both recommended to be 0.1 mg·kg^^-1.The TMDI of flonicamid and bifenthrin were calculated to be 0.7981 mg and 0.2880 mg,and the CPLc was 5.53 and 2.19,respectively.According to the MRLs in USA,the TMDIs of flonicamid and bifenthrin were calculated to be 0.8210 mg and 0.3063 mg,and the CPLc was 5.37 and 2.06,respectively.The MRLs recommended in this study would be stricter than the USA MRLs,but they had a relatively consistent protection against the chronic dietary risk for Chinese consumers.The reason might be the lower risk contribution of peach.【Conclusion】The improved ethyl acetate QuEChERS-GC-ECD method was convenient and fast for simultaneous detection of flonicamid and bifenthrin.In accordance with the recommended use of PHI,the RQc of the two pesticides in peach were acceptable.The MRLs recommended in this experiment for peach are stricter than those in USA,but the protection levels against the chronic dietary risk for Chinese consumers are similar.