| Environmental pollution caused by chemical pesticide spraying drift has become a global focus.At present,the respiratory exposure assessment of pesticides on human health is mainly based on the total amount of respiratory exposure to pesticides obtained by air sampler sampling the ambient air,which may cause great uncertainty in the assessment results and affect the formulation of rational use guidelines for pesticides and the risk control of pesticide residue pollution at application sites.Inhalation bioaccessibility is an important factor to accurately reflect the actual exposure level of pesticide residues in human body.How to apply it to the respiratory exposure assessment of chemical pesticides has become an urgent scientific problem to be solved.In this paper,we selected triadimefon,tebuconazole,metconazole and epoxiconazole established an in vitro assay methods of inhalation bioaccessibility of triazole fungicides based on Gamble Solution（GS）,Simulated lung fluid（SLF）and Artificial Lung Fluid（ALF）,evaluated the inhalation bioaccessibility of three simulated lung fluids and their influencing factors,and the respiratory exposure level of tested pesticides was quantitatively analyzed in combination with the respiratory exposure amount of tested pesticides in the scenario of simulated electric spray application,The results provide scientific basis and technical support for the evaluation of pesticide inhalation health.The main results are as follows:1.The multi-residues analytical methods for four triazoles in simulated lung fluid and sampling media（XAD-2 resin）A method was developed and optimized for the analysis of four triazoles residues in simulated lung fluid.The recoveries of triazoles residues in simulated lung fluid GS、SLF、ALF were in the range of 83.16-113.17%at fortified levels of 0.5,1.0 and 10μg/kg,the RSD of three quintuplicates for the four triazoles residues were 0.02-10.02%;The linearity was good in the concentration range of 1-100μg/kg and the correlation coefficients（r2）of four triazoles residues were 0.9989-0.9999;The limits of detection（LOD）and quantification（LOQ）were 0.01-0.05μg/kg and 0.06-0.15μg/kg,respectively.The recoveries of triazoles residues in XAD-2 were in the range of 72.07-111.47%,at fortified levels of 0.1,0.5 and 1.0 mg/kg,the RSD of three quintuplicates for the four triazoles residues were 2.05-6.77%;The linearity was good in the concentration range of 0.1-20μg/kg and the r2of four triazoles residues were 0.9982-0.9996;The LOD and LOQ were0.26-0.29μg/kg and 0.89-0.99μg/kg,respectively.Results demonstrated the residue method can fulfil the requirements for pesticide residue analysis.2.The in vitro method for the determination of inhalation bioaccessibility of tested pesticidesEffects of retention time,solid-liquid（S/L）ratio and the oscillation rate on the in vitro measurement method of inhalation bioaccessibility were studied.The results showed that the inhalation bioaccessibility of four triazole fungicides in the three simulated lung fluids increased with retention time and reached the release equilibrium at 6 h.With the increase of solid-liquid ratio（S/L）,the bioaccessibility of the four triazole fungicides was relatively high when the solid-liquid ratio was 1/1500.When the oscillation rate was 150 r/min,the bioaccessibility of the tested pesticides was relatively high.Response surface methodology（RSM）was used to optimize the above influencing factors,and the optimal parameters of the in vitro determination method for maximum inhalation bioaccessibility were determined as:The retention time of 10.25 h、S/L ratio of1/1500、oscillation rate of 130 r/min in Gamble solution;the retention time of 9.75 h S/L ratio of 1/1500、oscillation rate of 140 r/min in Simulated lung fluid,the retention time of9.12 h、S/L ratio of 1/1500、oscillation rate of 130 r/min in Artificial lung fluid.3.Study on variability of four triazole fungicides inhalation bioaccessibilityThe inhalation bioaccessibility of the tested pesticides in the simulated lung fluid was determined.Results showed that inhalation bioaccessibility of triadimefon,tebuconazole,metconazole,and epoxiconazole in GS was 40.56%,43.48%,35.61%,33.75%,respectively;in SLF was 50.78%,50.37%,47.10%,43.59%,respectively;in ALF was36.11%,42.45%,32.44%and 30.74%,respectively.Based on the differences of inhalation bioaccessibility of tested pesticides in different simulated lung fluid,the effects of different contents of protein and L-cysteine and different doses of tested pesticides on inhalation bioaccessibility of four triazole fungicides were evaluated using protein and L-cysteine as representative.The results showed that the inhalation bioaccessibility of the tested pesticides in three kinds of simulated lung fluid was positively correlated with the addition levels of protein and L-cysteine.When the addition levels were 1.5%and 1.2%,the inhalation bioaccessibility of the four triazole fungicides increased by 20.63-34.95%and 24.39-31.52%,respectively.The bioaccessibility of four triazole fungicides decreased 21.41-38.16%by increasing pesticide residues.4.Determination of tested pesticides’unit exposure under simulated applicationXAD-2 was used as sampling medium to determine the unit exposure（UE）of the tested pesticides in the scenario of electric spray.The results showed that at the recommended dose of 24 m L/667m2,the UE value of 44%triadimefon suspending agent was 588.48 ng/m3and 944.96 ng/m3when the AD120-02 circular nozzle and F110-02 fan nozzle were applied;At the recommended dose of 15 m L/667m2,the UE values of 43%tebuconazole suspending agent were 135.50 ng/m3and 269.17 ng/m3when the AD120-02circular nozzle and F110-02 fan nozzle were applied;At the recommended dose of 10m L/667m2,the UE value of 40%metconazole suspension agent was 69.94 ng/m3and77.26 ng/m3when the AD120-02 circular nozzle and F110-02 fan nozzle were applied;At the recommended dose of 60 m L/667m2,the UE values of 12.5%epoxiconazole suspension agent was 60.87 ng/m3and 64.89 ng/m3when the AD120-02 circular nozzle and F110-02 fan nozzle were applied.The relatively small particle size of droplet produced by fan-shaped spray nozzle may be the main reason for its relatively large unit exposure.5.Respiratory exposure assessment of triazoles based on inhalation bioaccessibilityBased on the unit exposure of 4 triazole fungicides in F110-02 fan sprinkler application scenario,combined with the obtained inhalation bioaccessibility of the tested pesticides,Respiratory Exposure assessment results showed that the total respiratory exposure(RETotal)of triadimefon,tebuconazole,metconazole and epoxiconazole was4.03×10-5,1.15×10-5,3.29×10-6and 2.77×10-6mg·kg-1·day-1,respectively.However,based on the respiratory exposure(REBA)were 1.46×10-5-2.05×10-5,4.88×10-6-5.79×10-6,1.07×10-6-1.55×10-6and 8.51×10-7-1.21×10-6mg·kg-1·day-1,respectively.Therefore,without the key factor of inhalation bioaccessibility,respiratory exposure of tested pesticides would be overestimated by 50-68%. |
PDF Full Text Request