| 题名 | 新型杀菌剂肟菌酯的环境行为研究 |
| 作者 | 刘慧君 |
| 学位类别 | 博士 |
| 答辩日期 | 2014-05 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 李建中 |
| 关键词 | 肟菌酯 环境行为 降解 吸附 迁移 生物富集 Trifloxystrobin Environmental Behaviors Degradation Adsorption Migration Bioaccumulation |
| 其他题名 | Reasearch on Enviromental Behavior of New Type Fungicide Trifloxytrobin |
| 学位专业 | 环境科学 |
| 中文摘要 | 肟菌酯是一类甲氧基丙烯酸酯类杀菌剂，广泛应用于水果、蔬菜、小麦、水稻等农作物，对多种真菌性病害具有良好的防效。为了全面评估肟菌酯对环境和非靶标生物的安全性，本论文对肟菌酯的水解、光解、土壤降解、淋溶、吸附、以及在青鳉鱼体内的组织分布、生物富集和内分泌干扰效应进行了研究，为预测肟菌酯在环境中的行为动态，评估肟菌酯的环境安全性和指导用药提供了重要的数据支持和理论依据。 论文的主要研究结果如下： 建立了肟菌酯在水中、土壤中和鱼中的残留检测方法，最低检出浓度分别为 0.1 μg/L、0.5 mg/kg和 0.001 mg/kg，添加回收率 74.1%-95.2.3%，相对标准偏差 2.95%-8.92%，方法的灵敏度、准确度和精密度均达到农药残留检测要求。 研究了肟菌酯在土壤中的降解及其影响因子。结果表明：（1）在土壤含水量为饱和持水量的 10%~90%，培养温度 0~50℃范围内，随着含水量增加，温度升高，肟菌酯降解速率加快。（2）土壤微生物对肟菌酯降解有显著影响，好氧条件下，肟菌酯以微生物降解为主，厌氧条件下，以非生物降解为主，厌氧土壤中的非生物降解快于好氧土壤。（3）不同类型土壤中，肟菌酯降解速率厌氧＞好氧，厌氧条件下，黑土＞红壤＞潮土，好氧条件下，红壤＞黑土＞潮土。肟菌酯在土壤中降解与有机质含量和粘粒含量相关。 研究了肟菌酯在土壤中的吸附及淋溶特性。试验结果表明：（1）肟菌酯在土壤中的吸附符合―L‖型 Freundlich等温吸附。肟菌酯在土壤中同时存在可逆吸附和不可逆吸附，且以自发物理吸附过程为主，吸附性能黑土＞红壤＞潮土。肟菌酯在 3 种土壤中较易吸附，表明肟菌酯对地下水污染的风险性较小。（2）肟菌酯在土壤中几乎不会随毛细水移动，但雨水的渗漏和重力作用会引起土壤尤其是砂土表面的肟菌酯向下层土壤迁移。 研究了肟菌酯的水化学降解。试验结果如下：（1）pH6.0-pH10.0 范围内，肟菌酯水解速率常数 k随着 pH值升高而增加，lgk和 pH值成线性正相关。25℃下，肟菌酯在 pH值 8.0～10.0水溶液中,属易降解，在 pH7.0水溶液中属中等降解，在 pH6.0 水溶液中属较难降解。（2）温度升高，肟菌酯水解速率加快，温度效应系数为 2.1-2.4。活化能 Ea为 56.67-101.17 kJ/mol。（3）肟菌酯活化焓(△H)随 pH升高而降低，但受温度影响较小。活化熵(△S)随着温度和 pH增加而减少，表明活化熵的降低有利于肟菌酯水化学降解发生。（4）0-15 mg/L腐殖酸水溶液中，腐殖酸浓度和肟菌酯水解半衰期成良好的线性负相关，水溶液中腐殖酸可加快肟菌酯水解速率。（5）25℃黑暗条件下，肟菌酯在稻田水、沟渠水和饮用水中水解速率沟渠水＞稻田水＞饮用水，属较难降解。 研究了肟菌酯的光化学降解行为。试验结果表明：（1）肟菌酯不同 pH 值水溶液中光解速率 pH9.0＞pH7.0＞pH4.0，碱性越强，光解速率越快。光照一定时间后，pH4.0、pH7和 pH9缓冲液中肟菌酯 4种顺反异构体(EZ/EE/ZZ/ZE)达到动态平衡，EE在酸性水溶液中最稳定。（2）肟菌酯土壤表面光解速率潮土＞红壤＞黑土，光照一定时间后 4种异构体达到动态平衡，EE相对含量最高。 研究了肟菌酯在青鳉鱼(medaka, Oryzias latipes)体内的富集、分布和内分泌干扰效应。试验结果表明：（1）肟菌酯在青鳉鱼不同组织中富集浓度大小顺序不同，在脂肪组织中富集浓度最高，在鱼肉中最低。脂肪和鱼肠组织中，雄鱼肟菌酯富集浓度高于雌鱼，而鱼肉组织中则与之相反。肟菌酯在青鳉鱼体内生物富集系数（BCF）变化趋势与富集浓度一致，且暴露浓度越低，BCF越高，暴露浓度对数值与BCF之间存在良好的指数相关性。（2）青鳉鱼卵暴露在肟菌酯中会导致胚胎损伤、孵化率下降、胚胎和幼鱼致死率升高，表明肟菌酯能影响鱼早期发育。（3）性腺和多环芳香受体基因表达变化表明肟菌酯能干扰性激素功能，诱导幼鱼体内异源物质代谢。肟菌酯剂量和cyp1a mRNA 水平正调控具有明显的剂量-效应关系，cyp1a基因可作为比较敏感的潜在生物标记物，用于评估肟菌酯在鱼早期生命阶段的污染。 |
| 英文摘要 | Trifloxystrobin is a kind of strobilurin fungicide which is widely used in fruits,vegetables, wheat, rice and other corpsfor controlling a variety of fungal diseases effectively.Hydrolysis, photolysis, soil degradation, leaching, adsorption, and medaka fish tissue distribution, bioaccumulation and endocrine disrupting effects of trifloxystrobin were studied in order to fully assess the safety of trifloxystrobin to environment and non-target organisms.The research provided important data support and theoretical basis for predictding the dynamic behavior of trifloxystrobin in the environment, assesssing the environmental safety of trifloxystrobin, and guiding people to rationally use pesticides. The main results of this paper were listed as follows: Methods for determine the residue of trifloxystrobin in water, soil and fish were established. The minimum detection limits were0.1 μg/L, 0.5 mg/kg and 0.001 mg/kg.The average recovery of trifloxystrobin was in the range of 74.1% to 95.2.3%. The relative standard deviation was 2.95%-8.92%. The sensitivity, accuracy and precision of the methods were within acceptable range. The degradation of trifloxystrobin in soils and its influence factors were investigated. The results were summarized as following: (1). The degradation rate of trifloxystrobin accelerated with the soil moisture and termperature increasing in 10%-90% full-water capacity and 0-50℃. (2) Microorganismswould accelerate the degradation of trifloxystrobin in soil. Trifloxystrobin was maily biodegradable and non-biodegradable inaerobic and anaerobic res conditions pectively. (3) The degradation rate of trifloxystrobin in soils was anaerobic > aerobic, black soil> red soil >chao soil under anaerobic conditions and red soil> black soil>chao soil under aerobic conditions, indicating degradation of trifloxystrobin in soilswere affected bywater content, pH, organic matter content, clay content and other factors. The adsorption and leaching of trifloxystrobin in soils were studied in laboratory.Results exhibited: (1) Adsorption isotherms of trifloxystrobin in soil such as chao soil, black soil and red soil could be descriptioned byFreundlichequation.The adsorption largely resulted from spontaneous physical adsorption.Contamination risk of trifloxystrobin to groundwater was small. (2) Trifloxystrobin hardly moved with capillary water, but the rain leakage and gravity would cause trifloxystrobin on the surface of the sand migrating to subsoil. The hydrolysis kinetics and mechanisms of trifloxystrobin in aqueous solutions were studied. Results were observed as follow: (1)Trifloxystrobin hydrolysis coefficient (k) increased with pH increasing and lgk was positive linear correlated with pH values within the range of pH6.0andpH10.0. (2) Trifloxystrobin hydrolysis accelerated when temperature rised. The temperature effect quotient (Q) was2.1 to 2.4 and the activation energy (Ea) was 56.67-101.17 kJ/mol. (3) Activation enthalpy(△H) for trifloxystrobin decreased with increasing pH, but less affected by temperature. Activation entropy (△S) increases when temperature and pH decreased, indicating reduced activation entropy could promotehydrolysis of trifloxystrobin. (4) Humic acid in aqueous solutions could accelerate the rate of trifloxystrobin hydrolysis. Hydrolysis rate increased with increasing concentration of humic acid and the hydrolysis half-life was negative linear correlated with humic acid concentration within 0 and 15 mg/L humic acid content. (5) Trifloxystrobin degraded the most fastlyin ditch water and slowly in drink water. The photodegradation of trifloxystrobin was studied. The results revealed that: (1) Photolysis rate of trifloxystrobin in pH9.0buffer solutionwasthe highest, followed by pH7.0 and pH4.0, showing thatbase contributedto photolysis. The four kinds of trifloxystrobin cis and trans isomers (EZ/EE/ZZ/ZE) in pH4.0, pH7.0 and pH9.0 buffer solutions displayed dynamic equilibrium after exposuring to xenon for about 48 h, 11 h and 7 h, respectively. EE was the most stable in acidic aqueous solution under light. (2) The photolysis rate of trifloxystrobin on soil surface was Chao soil>red soil> black soil with half-life of longer than 24 h andwas classified as difficult to photolysis. 4 isomers of trifloxystrobin obtained dynamic equilibrium about 29 h, 120 h and 44 h later under illumination in chao soil, black soil and red soil,respectively.The relative content of EE in soils was the highestunder illumination. Bioaccumulation, tissue distribution and endocrine disrupting effects in medaka (medaka, Oryzias latipes) exposed to different concentration of trifloxystrobin were stuied. The results were reported as following:(1) The highest concentration of trifloxystrobin was detected in fat but the lowest in muscle. Concentration of trifloxystrobin detected was higher in male than in female in fat and intestine while the result was opposite to it in muscle. Bioaccumulation factor (BCF) changed consistent with the concentration of trifloxystrobin in different tissues of medaka. BCF was higher exposured to low concentration of trifloxystrobin thanto high. It showed a good index correlation between Logarithmic of concentration and BCF. (2) Exposure to trifloxystrobin can result in embryo lesions, hatchability decrease, and larval mortality increase in embryonic and larval medaka. (3) Trifloxystrobin could disrupt sex hormone function and induce xenobiotics metabolism in larval fish. The cyp1a gene could be used as a more sensitive potential biomarker to assess trifloxystrobin contamination in early life stage of fish. |
| 公开日期 | 2015-07-08 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.rcees.ac.cn/handle/311016/15729]  |
| 专题 | 生态环境研究中心_中国科学院环境生物技术重点实验室 |
| 推荐引用方式 GB/T 7714 | 刘慧君. 新型杀菌剂肟菌酯的环境行为研究[D]. 北京. 中国科学院研究生院. 2014. |
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