| Nanopesticides are an innovative application of nanotechnology in the field of plant protection.The small-scale effects and controlled release properties of nanopesticides have significant advantages in increasing drug efficacy,prolonging effectiveness,and improving utilization.However,these effects can be a double-edged sword,potentially altering the exposure levels of pesticides to applicators,agricultural products,and the environment,and even posing risks.The application risk of nanopesticides has been a topic of much debate and urgently needs to be resolved.However,relevant research is significantly lagging behind,seriously impeding the registration,licensing,and industrialization of nanopesticides.This paper focuses on the insecticide emamectin benzoate,which has a promising future in nanotechnology applications,and systematically studies its health and dietary risks as well as the mechanism behind the risk in both carrier and non-carrier nanopesticide formulations.The experiments were conducted in four parts:1)establishing pre-treatment methods and instrument detection methods for emamectin benzoate in different matrices to lay the foundation for accurate quantitative analysis in subsequent experiments;2)dividing the nanopesticide formulation of emamectin benzoate into carrier and non-carrier groups,completing representative control formulation selection,formulation preparation,and basic property determination based on formulation characteristics,to lay the foundation for subsequent risk assessments and risk difference mechanism explanations;3)from the perspective of nanopesticide human exposure and exposure risk,designing typical field scenarios,measuring the dermal exposure,inhalation exposure,and final residue levels in edible parts of crops of different nanopesticide formulations,and evaluating the health risks to applicators and dietary risks to consumers based on relevant assessment formulas;4)from the perspective of behavior and potential risks after exposure to nanopesticide formulations in the body,simulating humans with rats,measuring absorption,distribution,excretion,and accumulation behaviors after dermal,inhalation,and oral exposure to different nanopesticide formulations,and conducting a preliminary analysis of potential risks.The main progress made is as follows:（1）An analytical method was established for the determination of flumequine benzoate,including instrumental analysis and sample pretreatment methods for 16 types of animal,plant,and environmental matrices.The limit of detection（LOD）of the instrumental method was 1μg/kg,and the lowest limit of quantification of the pretreatment method was 0.01 mg/L.The average recovery rate was between 85.0%and 113.6%,and the relative standard deviation（RSD）was between 0.6%and 6.6%.The accuracy and precision of the method were in accordance with the requirements of SANCO/12495/2011 for pesticide residue analysis.The accuracy and efficiency of the analytical method were improved by the application of internal standard preparation and volume weighing spoon.（2）The basic properties of non-carrier nanomaterials and their control formulation were measured.The nanomaterials were microemulsion and nanoemulsion,and the control formulation was emulsion.The results showed that the hydrated particle sizes of emulsion,microemulsion,and nanoemulsion were 105.18–179.59 nm,30.67–84.19 nm,and 24.27–67.61 nm,respectively,and the particle sizes of the three formulations were 152.38μm,130.78μm,and 138.8μm,respectively.The surface tensions were 30.73±0.68 m N/m,33.68±0.94 m N/m,and 39.87±0.87m N/m,respectively.（3）The human exposure and corresponding exposure risks of non-carrier nanomaterials and their control formulation were determined and evaluated.By designing a field experiment in a tomato greenhouse,the dermal exposure of the applicators was measured by the whole-body method,and the inhalation exposure was measured by air sampling method,the final residue of the tomato fruit after a safety interval was determined,and the occupational and dietary health risks of different formulations were evaluated using formulas.The results showed that the risk factors（RQ）of the three formulations after dermal exposure under good protection were 0.86,0.41,and 0.38,respectively,and the risk was acceptable.The potential dermal exposure risk of the emulsion was higher than that of the microemulsion and nanoemulsion.After inhalation exposure with a mask,the risk factors（RQ）of the three formulations were 0.13,0.12,and 0.27,respectively,and the risk was acceptable.The inhalation exposure risk of the nanoemulsion was higher than that of the emulsion and microemulsion.The acute and chronic dietary risk assessment results showed that the acute dietary risk（%ARf D）of the three formulations was 0.83,0.91,and 0.29,respectively,and the chronic dietary risk factor（RQ）was 75.1,75.3,and 74.6,respectively.The risk was acceptable.The acute and chronic dietary risks of the emulsion and microemulsion were higher than those of the nanoemulsion.We found the particle size and surface tension of the formulations were the main factors affecting the dermal exposure,inhalation exposure,and final residue of the edible parts of the crops of the applicators.（4）Absorption,excretion,distribution,accumulation behavior,and potential risks of non-carrier-based nanoscale formulations and their control formulation in rats were determined and evaluated.The results showed that the three formulations did not accumulate in tissue organs over time after exposure to rats by transdermal,inhalation,and oral routes,indicating no potential chronic risks.After exposure by transdermal and oral routes,the concentration of active ingredients in plasma,tissues,and organs was higher in the emulsion than in the microemulsion and nanoemulsion,indicating a higher potential acute risk of transdermal and oral exposure.After inhalation exposure,the concentration of active ingredients in plasma,tissues,and organs was higher in the microemulsion than in the emulsion and nanoemulsion,indicating a higher potential acute inhalation exposure risk.We found,the main factors affecting the entry of the formulations into rats by transdermal,inhalation,and oral routes were surface tension,spray particle size,organic solvent content,and surfactant content.（5）The carrier-based nanoscale formulation and their control formulation were prepared and their basic properties were determined.Nanospheres and control formulation microspheres were prepared.The results showed that both formulations had a regular spherical morphology with mean particle sizes of 250 nm and 10μm,respectively.The nanospheres were within the definition of nanoscale formulations with particle sizes≤300 nm currently adopted in China,while the microspheres had similar particle sizes to traditional microcapsule suspensions,and both formulations were representative for the study.The formulation loading capacities were LC nano=41.3%and LC micro=53.7%,and the sustained-release performance was in accordance with the logarithmic equation y nano=0.1548Ln（x）+0.204 and y micro=0.1376Ln（x）+0.125,with little difference in formulation loading and sustained-release performance,and the microspheres had higher formulation loading and slower release rates.The spray particle sizes of both formulations under field concentration were 173.03μm and 154.54μm,and the surface tensions were 45.67±0.93 m N/m and 45.15±0.94 m N/m,respectively.The prepared formulations remained stable in particle size and active ingredient content for more than 3 months under normal temperature and darkness.（6）The human exposure levels and corresponding exposure risks of carrier-based nanoformulation and its control formulation were measured and evaluated,using the same field test method as non-carrier-based formulations,and an indoor penetration test was designed to assist in the proof.The results showed that the risk factors（RQs）of the nanosperes and microsperes after dermal exposure under good protection were 0.16 and 0.23,respectively,with an acceptable risk.There was no significant difference in the dermal exposure risk between the nano-sphere and micro-sphere formulations.The indoor penetration test proved that both nano-sphere and micro-sphere could not penetrate the outer clothing layer.Only the active ingredients dissolved in water could penetrate the inner clothing layer through the solution.After inhalation exposure,the risk factors（RQs）of the two formulations with wearing masks were 0.09 and 0.10,respectively,with an acceptable risk.The inhalation exposure risk of the micro-sphere was greater than that of the nano-sphere.The acute and chronic dietary risk assessment results showed that the acute dietary risk（%ARf D）of the two formulations was 0.60 and 1.56,respectively,and the chronic dietary risk factors（RQs）were 74.80 and 75.48,respectively,with an acceptable risk.The acute and chronic dietary risks of the micro-sphere were higher than those of the nano-sphere.We found,the main factors affecting the dermal exposure,inhalation exposure,and final residual levels in edible parts of crops for applicators are the surface tension,spray particle size,and sustained-release performance of the formulations.（7）The absorption,excretion,distribution,and potential risks of carrier-based nanomaterials and their control formulation were determined and evaluated in rats.The results showed that after exposure through transdermal,inhalation,and oral administration,neither of the two formulations accumulated in tissue organs over time,thereby posing no potential chronic risks.After exposure through transdermal,oral administration,and inhalation,the concentration of the active ingredient in the plasma,tissue,and organs was generally higher in the nanospheres than in the microspheres,which led to a higher potential risk of acute exposure through dermal,oral administration,and inhalation.After inhalation exposure,the concentration of the nanospheres in the lungs was significantly higher than that of the microspheres and the smaller size non-carrier formulations.The peak concentrations of the five formulations（nanospheres,microspheres,emulsion,microemulsion,and nanoemulsion）in the lungs were 1118.34μg/kg,152.57μg/kg,153.47μg/kg,202.01μg/kg,and 148.96μg/kg,respectively.Therefore,special attention should be paid to the acute pulmonary toxicity of the nanospheres after inhalation exposure. |
