【作者】 韩平；

【导师】 曹永松；

【作者基本信息】 中国农业大学 ， 植物检疫与农业生态健康， 2017， 博士

【摘要】 本论文以新型吡唑酰胺类杀菌剂氟唑菌苯胺作为研究对象,系统地开展了药剂在主要环境介质水体、土壤和植物中降解与迁移转化等环境行为,为其环境安全性评价提供详实数据和科学依据。通过系列的相关实验研究,论文获得了以下主要结果:采用优化后QuEChERS方法,建立了土壤中氟唑菌苯胺的UPLC-MS/MS检测方法,检出限为0.130μg/kg,添加回收率为87.8%-109.5%;采用固相萃取法,建立了水体中氟唑菌苯胺的UPLC-MS/MS检测方法,检出限为0.0033 μg/L,添加回收率为70.6%-95.6%。建立的检测方法适用于检测土壤和水体中的氟唑菌苯胺残留,同时适用于氟唑菌苯胺在土壤和水体中降解行为的研究。氟唑菌苯胺水降解行为研究结果表明,氟唑菌苯胺在酸性和中性条件下比较稳定,在碱性条件下水解速率较快,在pH3、pH7和pH11缓冲液中的水解半衰期分别为449.8 d、392.7d和297 d;在25℃、35 ℃和50 ℃条件下的水解率没有显著性差异,其降解半衰期分别为383.8 d、389.5 d 和 417.3 d。氟唑菌苯胺光降解行为研究结果表明,氟唑菌苯胺在蒸馏水、自来水和河水中的光解半衰期分别为221.0 h、165.9 h和167.3 h;在不同pH值(3,7,11)的缓冲液中的光解半衰期分别为181.8h、159.9h和180.4h;光敏剂核黄素、双氧水、三价铁离子能促进氟唑菌苯胺的光解;在自然条件下,氟唑菌苯胺在太阳光条件下的光解半衰期为49.7 d,光解动态符合经典一级动力学模型。拟合氟唑菌苯胺在3种供试土壤中的吸附等温线,其在北京土壤、黑龙江土壤和云南土壤中的吸附常数Kf-ads分别为28.49、40.44和12.92。土壤对氟唑菌苯胺吸附能力的大小为黑龙江土壤>北京土壤>云南土壤。药剂在北京土壤和黑龙江土壤中的吸附等温线属于L型等温线;在云南土壤中的吸附等温线属于S型等温线;药剂在3种土壤中的吸附自由能ΔG范围为14.47～18.64 KJ/mol,其在土壤中的吸附属于物理吸附过程。氟唑菌苯胺在土壤中降解行为研究结果表明,氟唑菌苯胺在北京土壤、黑龙江土壤和云南土壤中的降解半衰期分别为71.5 d、59.2 d和101.9 d,土壤中有机质(有机碳)含量是影响氟唑菌苯胺在土壤中降解的关键因子;药剂在供试北京土壤水土比1:5(田间持水量)条件下的降解速率最快,淹水条件次之,而在土壤水土比1:10条件下的降解速率最慢;药剂在土壤中的降解速率随着温度的升高而加快;氟唑菌苯胺在灭菌和非灭菌土壤中降解速率存在较大的差异。氟唑菌苯胺在小麦植株中吸收传导行为研究结果表明,根部施药,能快速被小麦植株吸收,并快速向茎叶部传导;叶部单叶片施药,能快速被叶片吸收,并可以跨叶传导至其他叶片并累积,进而在茎部和根部累积。更多还原

【Abstract】 Penflufen developed by Bayer Crop Science,is a new fungicide of the pyrazole amide group,mainly used for seed treatment,and the registed covering in-furrow and seed piece treatments for potatoes,alfalfa,vegetables,and cereals.In this study,the environmental behavior including hydrolysis,photolysis,adsorption/desorption and degradation in different types of water and three contrasting soils of China was investigated for evaluating the environmental safety.In the present study,optimized QuEChERS and solid phase extraction were employed to develop a sensitive Ultra-performance liquid chromatography tandem mass-spectrometry detection(UPLC-MS/MS)method for quantification of penflufen in environmental waters and soils.The recoveries ranged from 87.8%to 109.5%for soils,and ranged from 70.6%-95.6%for waters,respectively.The established method is suitable for the determination of the residues of penflufen in soil and water,and the study of its degradation behavior in soil and water.The kinetics of hydrolysis of penflufen was studied in several aqueous buffers in the pH range 3-7 and in different temperature conditions.Penflufen was stable in acidic and neutral solution.Hydrolysis half-lives of penflufen in pH3,pH7 and pH 11 buffer were 449.8 d,392.7 d and 297 d,respectively.There was no significant difference in the hydrolysis rate of penflufen under 25℃,35 ℃ and 50 ℃conditions.The degradation half-lives were 383.8 d,389.5 d and 417.3 d,respectively.The photodegradation kinetics of penflufen in various conditions was investigated by UV and solar irradiation.Photolytic half-lives of penflufen in distilled water,tap water and river water were 221 h,165.9 h and 167.3 h,respectively.Photolysis half-lives in buffer solution of different pH(3,7,11)values were 181.8 h,159.9 h and 180.4 h,respectively.Adding high concentration of photosensitizer riboflavin,hydrogen peroxide and ferric ion could promote the photolysis of penflufen.Under natural condition,photolysis half-life of penflufen under solar light was 49.7 d.The photolysis rates of penflufen were characterized by a first-order kinetic model.The adsorption and desorption behavior of penflufen was studied.Freundlich equation was used to fit the adsorption isotherm of the reagent in three kinds of soil.The adsorption constants(Kf-ads)of penflufen in Beijing soil,Heilongjiang soil and Yunnan soil were 28.49,40.44 and 12.92,respectively,The adsorption capacity of soils for penflufen was Heilongjiang soil>Beijing soil>Yunnan soil.Adsorption isotherms of penflufen in Beijing soil and Heilongjiang soil belonged to L type isotherm,but for Yunnan soil belonged to S type isotherm.Adsorption free energy(ΔG)of penflufen in the three soils ranged from 14.47 t0 18.64 KJ/mol.It revealed that adsorption of penflufen in the soil belonged to physical adsorption process.The degradation kinetics of penflufen was investigated in three types of soil.Half-lives of penflufen were 71.5,59.2,and 203.9 days in Beijing soil,Heilongjiang soil and Yunnan soil under laboratory condition,respectively.In Beijing soil,dissipation rate of penlfufen was higher in non-sterile than it in sterile conditions.Under different soil temperature and moisture conditions,the dissipation of the pesticide was the fastest in 50 ℃ or field capacity soil.On the basis of the above findings,we proposed that penflufen was moderately stable in different soil types,and soil temperature,moisture,organic matter,and the microbial population were key factors influencing on the dissipation of penflufen in soil.The absorption and transform behavior of penflufen were investigated in wheat.Under root application condition,penflufen could quickly be absorbed by wheat plants,and quickly transferred to the stems and leaves.Under leaf spraying condition,penflufen could be quickly absorbed by the leaves,and transferred and accumulated to other leaves,then accumulated in the stem and root.更多还原