Monitoring Of Pesticide Residues In Pollen, Beebread And Honey And Exposure Risk Assessment On Apis Mellifera L.

Honeybee,a social insect,has important worth for nature and humans through maintaining ecological balance and promoting crop yield increase by the pollination of honey plants.A phenomenon named colony collapse disorder(CCD),which a large number of honeybee colonies,has gradually disappeared around the world in recent years,and the one reason for this phenomenon has been deemed that the chemical pesticide residues in environment.In this paper,a multi-residue analysis method,which used some new purification material(including PSA/GCB SPE column and MCNTs)based on GC-MS(Gas chromatography-mass spectrum)and UPLC-MS/MS(Ultra-high-performance liquid chromatography-tandem mass spectrometry),has been established for monitoring 64kinds of pesticide residues in 641 total of pollen,beebread and honey samples collected from five major honey source regions in China depended on 13 National Bee Industry System Test Stations.Based on the EPPO's risk assessment state for honeybees,a program of evaluating the exposure risk of chemical pesticides on honeybees had been optimized and established to assess the exposure risk of six pesticides commonly used in major honey source regions around China on Apis mellifera L.This work provided basis for the rational application of pesticides on honey plants.The main results were as following:1.Multi-residue analytical method for 12 pesticides(such as bifenthrin)in pollen and other two matrixes used GC-MS.The pollen and beebread samples were vortexed with 1%acetic acid acetonitrile solution.The extracts were purified by PSA/GCB cartridges.The honey samples were vortexed with acetonitrile and purified by salting out.The test solutions were detected by GC-MS.The results of recovery experiments which 12 pesticides in pollen,beebread,and honey at three added levels showed that,the recoveries of the pesticides in pollen ranged from 78%to 119%with RSDs less than 19%.The recoveries of the pesticides in beebread were ranged from 74%and 112%,and RSDs were less than 18%.The recoveries of the pesticides in honey were ranged from 70%and 108%,and RSDs were less than 12%.The LOQ of 12 pesticides in the three matrixes were ranged from 5-20 ng/g.The accuracy,accuracy and sensitivity of this residual analysis method all suit the requirements of pesticide residue analysis.2.Multi-residue analytical method for 52 pesticides(such as chlorpyrifos)in pollen and other two matrixes used UPLC-MS/MS.Based on Qu ECh ERS method,multi-residue analysis method for 52 pesticides in pollen,beebread and honey were established on UPLC-MS/MS.The matrix extract of pollen and beebread was purified by purification filler which combined with PSA:C₁₈:MCNTs:Mg SO₄=1:1:0.03:3,and the matrix extract of honey was purified by purification filler which combined with PSA:C₁₈:Mg SO₄=1:1:3.The test solutions were detected by UPLC-MS/MS.The results of recovery experiments which 52 pesticides in pollen,beebread,and honey at three added levels showed that,the recoveries of the pesticides in pollen ranged from 71%to 125%with RSDs less than 19%.The recoveries of52 pesticides in beebread were ranged from 68%and 127%,and RSDs less than 18%.The recoveries of 52 pesticides in honey were ranged from 70%and 125%,and the coefficient of variation was less than 17%.The LOQ of 52 pesticides in the three matrixes was ranged from 2.5-10 ng/g.The accuracy,accuracy and sensitivity of this residual analysis method all suit the requirements of pesticide residue analysis.3.The monitoring of 6 commom pesticide residues contaminations in pollen and other two samples.The 189 pollen samples,226 beebread samples and 256 honey samples from five major regions of honey plant production(including Southwest,the middle and lower reaches of Yangtze River,the middle and lower reaches of Yellow River,Loess Plateau and Northeast)in China in 2016 and 2017 were collected and analyzed.The results showed that the pesticides with a higher detection percent in pollen were carbendazim(75.7%),fluvalinate(53.4%),chlorpyrifos(51.3%),fenpropathrin(45.0%),bifenthrin(32.3%),deltamethrin(18.0%),diflubenzuron(18.0%),thiamethoxam(17.5%),lambda-cyhalothrin(16.9%),fenvalerate(14.8%),triadimefon(14.3%),coumaphos(12.2%)and imidacloprid(10.6%).The pesticides with high detection percent in beebread samples were carbendazim(78.3%),fluvalinate(54.4%),diflubenzuron(42.0%),fenpropathrin(38.5%),chlorpyrifos(35.4%),coumaphos(20.0%),triadimefon(15.9%),fenvalerate(15.0%),bifenthrin(13.3%),trichlorfon(13.3%),and imidacloprid(12.0%).The pesticides with higher detection percent in honey samples were carbendazim(23.7%),pyrimethanil(21.0%),bifenthrin(16.2%)and lambda-cyhalothrin(15.0%).The polluted level of pesticide residues in the three kinds of matrix was pollen,beebread and honey in descending order,the pesticide residue pollution in pollen and honey gradually decreased from spring to autumn,while the pesticide residue pollution in beebread was slightly higher in autumn than in summer.The pollution of pesticide residues in the middle and lower reaches of the Yellow River around the five major honey plant regions were relatively serious.Imidacloprid,thiamethoxam and other common pesticides were gradually degrading during the formation of beebread.4.The exposure risk assessment of six common pesticides on Apis mellifera L.In accordance with the risk assessment principle of pesticides on environmental organisms,a pesticide risk assessment system for honeybees based on the EPPO was developed,and a model for assessing the exposure risk of honeybees to honeybees was optimized and established.Hazard quotient(HQ)was used to assess the exposure risk of pesticides to honeybees,toxicity exposure ratio(TER)was used to assess the acute oral exposure risk of pesticides to bee adults and larvae,half-lethal time(T₅₀)was used to assess the chronic oral exposure risk of pesticides to bee adults and larvae.The established risk assessment model was used to assess the exposure risk of six common pesticides,which detected in five major honey source regions around China,on Apis mellifera L.The results of the exposure assessment of six common pesticides on Apis mellifera L.adult showed that the pesticides with higher risk were chlorpyrifos and bifenthrin,moderate risk pesticides were fenpropathrin,imidacloprid and thiamethoxam,and the low risk pesticide was carbendazim.The acute oral exposure risk assessment of six pesticides on Apis mellifera L.adults showed that the pesticides with high risk were imidacloprid and thiamethoxam,the moderate risk pesticides were chlorpyrifos,fenpropathrin and bifenthrin,carbendazim with low risk.Assessing the acute oral exposure risk of imidacloprid and thiamethoxam on Apis mellifera L.larvae,the results show that imidacloprid was moderately risk,thiamethoxam was low risk.Six pesticides against Apis mellifera L.chronic oral exposure risk assessments of adults showed that imidacloprid and thiamethoxam were moderately risk,with low risk of chlorpyrifos,fenpropathrin,bifenthrin,and carbendazim.Imidacloprid and thiamethoxam were evaluated.The chronic oral exposure risk of Apis mellifera L.larvae showed that imidacloprid was moderate risk and thiamethoxam was low risk.