新农药氟吡菌酰胺在环境中的转化机理及其转化产物的生物毒性研究

发布时间：2017-12-27 09:28

本文关键词：新农药氟吡菌酰胺在环境中的转化机理及其转化产物的生物毒性研究　出处：《北京科技大学》2017年博士论文　论文类型：学位论文

【摘要】：农药施于环境后,在生物和非生物作用下会生成多种转化产物,使得生物体可能暴露于农药及其转化产物的混合体系中。研究表明,农药转化产物可能含有母体农药的毒核、是农药的活性成分、生物富集因子增加和作用模式多样化,在一定程度上影响甚至决定母体农药对环境及非靶标生物的安全性,因而近些年来受到了越来越广泛的关注,并被归入"新兴污染物"范畴。然而,对于很多农药,尤其是新型农药,它们在环境中的转化机理及其转化产物的相关信息依然十分匮乏。氟吡菌酰胺是拜耳作物科学公司研发的一种新型吡啶乙基苯甲酰胺类杀菌剂,杀菌谱广,防治效果好,已在我国获得登记并且大规模推广使用,也在世界其他国家和地区得到广泛的应用,但是目前关于其环境转化和转化产物等方面的研究鲜见报道。为了探明氟吡菌酰胺在水和土壤环境中的降解行为、转化机理和转化产物的生物毒性,本课题研究了氟吡菌酰胺在实验室条件下水体中的光化学降解机理和土壤中的降解行为以及氟吡菌酰胺和它的光化学转化产物的生物毒性,主要取得如下结果:1.氟吡菌酰胺在50±1℃,pH 4.0、7.2、9.0和黑暗条件下培养5 d,水解率小于8.1%。依据美国环保署颁布的EPA712-C-08-012,可得出氟吡菌酰胺在25℃条件下的水解半衰期大于一年,对水解稳定。因此,在下述光解研究过程中,水解造成的影响可以被忽略。2.结合LC-QqQ-MS/MS和LC-IT-TOF-MS/MS技术的分析结果,氟吡菌酰胺在高压汞灯和氙灯下水环境中主要生成三个光化学转化产物,分别为2,9-二(三氟甲基)-6,7-二氢吡啶[2,3-e][2]环苯亚胺-8(5H)-萘酮(TPⅠ)、N-(2-[3-羟基-5-三氟甲基-2-吡啶]乙基)-2-三氟甲基苯甲酰胺(TPⅡ)和N-(2-[5-三氟甲基-2-吡啶]乙基)-2-三氟甲基苯甲酰胺(TPⅢ),其中TPⅠ的最高生成量超过20%,TPⅡ约为9%,TPⅢ小于1%。通过比较高压汞灯下,水、乙腈和3%异丙醇-水(v:v)中氟吡菌酰胺的光解速率和降解产物含量的差异,推断TPⅠ是经过自由基中间体发生分子内的脱氯环化形成的,TPⅡ是活性氧亲核取代形成的,TPⅢ是抽氢反应形成的。TiO_2在氙灯下催化氟吡菌酰胺光化学降解主要生成6个产物,经LC-IT-TOF-MS/MS分析表明,其中两个产物与TPⅠ和TPⅡ相同,其余四个分别为3-氯-5-三氟甲基-2-吡啶乙基胺(TPⅣ)、3-氯-5-三氟甲基-2-吡啶乙基甲酰胺(TPⅤ)、N-(2-[3-氯-5-三氟甲基-2-吡啶]乙基)-2-三氟甲基-6-羟基苯甲酰胺(TPⅥ)和N-(2-[3-氯-5-三氟甲基-2-吡啶]乙基)-2-三氟甲基-4-羟基苯甲酰胺(TPⅦ),这些产物的形成途径主要是亲核取代和酰胺键的断裂。Fe(Ⅲ)在氙灯下敏化氟吡菌酰胺光化学降解主要生成7个产物,同样经LC-IT-TOF-MS/MS分析表明,其中三个与TP Ⅰ-Ⅲ相同,三个与TP Ⅳ、TP Ⅵ和TP Ⅶ相同，余下一个为3-氯-5-三氟甲基-2-吡啶乙酰胺(TP Ⅷ),形成途径除上述途径外,还包括光氧化作用。3.研究了在高压汞灯和氙灯下,Fe(Ⅲ)、Cu(Ⅱ)、(NO_3)~-、腐殖酸、富里酸和核黄素这几种自然水体组分,pH和TiO_2对氟吡菌酰胺光转化的影响。在两种光源下,氟吡菌酰胺在中性条件下较碱性和酸性下光解快,最快可达两倍。在高压汞灯下,TiO_2表现出低浓度的促进效果和高浓度的抑制效果;水体组分主要表现出抑制效果,其中核黄素抑制效果最明显,可达12.5倍,腐殖酸次之,可达10倍,其余的小于三倍。在氙灯下,TiO_2表现出明显的催化效果,最大催化效果可达17倍;Fe(Ⅲ)表现出明显的敏化效果,最高可达79倍;Cu(Ⅱ)和(NO_3)~-表现出低浓度的促进效果和高浓度的抑制效果,核黄素则与二者相反;富里酸表现出抑制效果,最高达两倍;腐殖酸表现出"S"型效果。4.建立了氟吡菌酰胺在我国三种典型土壤中的残留分析方法,方法平均添加回收率在97-105%之间,相对标准偏差在3.9-11.6%之间,最低定量限为0.1mgkg~(-1),最低检出限为5.0-7.5μgL~(-1),基质匹配标准曲线相关线性系数大于0.99。用建立的分析方法研究氟吡菌酰胺的土壤降解行为,结果表明氟吡菌酰胺在非灭菌条件下不同土壤含水量和土壤类型中的降解半衰期为55.4-69.3 d,在灭菌条件下不同土壤含水量和土壤类型中的降解半衰期大于一年。这说明所试验土壤类型对氟吡菌酰胺的土壤降解影响不显著,微生物降解是氟吡菌酰胺在土壤中降解的主要方式。根据我国关于农15在土壤中的降解性等级划分的标准,氟吡菌酰胺属于较易降解农药。此外,通过对比0、7、30、60d的色谱图,未发现氟吡菌酰胺主要的土壤降解产物。5.利用发光细菌毒性试验研究氟吡菌酰胺在高压汞灯和氙灯下的光解溶液的急性毒性,结果表明随着光照时间的延长,光解溶液对发光细菌的毒性增加,说明氟吡菌酰胺在光解过程中可能生成毒性更高的产物。利用化学合成法合成主要光转化产物TP Ⅱ,然后用发光细菌毒性试验研究氟吡菌酰胺和TP Ⅱ的急性毒性,结果表明TP Ⅱ抑制发光细菌发光,抑制率随TP Ⅱ浓度的增加而增加,氟吡菌酰胺刺激发光细菌发光,刺激效应随氟吡菌酰胺浓度的增加而先增大后减小,TP Ⅱ对发光细菌的毒性比氟吡菌酰胺更强。选择ECOSAR和T.E.S.T.软件预测氟吡菌酰胺及其8个光转化产物的毒性,结果表明氟吡菌酰胺的光化学转化产物的预测毒性与氟吡菌酰胺相当或更高,其中主要产物TP Ⅰ和TP Ⅱ的大鼠经口急性毒性比氟吡菌酰胺高约一个数量级。综上所述,需要进一步研究TP Ⅰ和TP Ⅱ的生物毒性,并全面评估其环境和健康风险。
[Abstract]:When pesticides are applied to the environment, they will generate many transformation products under biological and abiotic effects, so that organisms may be exposed to the mixed system of pesticides and their transformation products. Research shows that pesticide transformation products may contain toxic pesticides, nuclear matrix is an active ingredient, pesticide bioaccumulation factor increased and the mode of action of diversification, to a certain extent, even determines the safety of parent pesticides on the environment and non target organisms, which in recent years has attracted more and more attention, and is included in the category "the emerging pollutants". However, for many pesticides, especially new pesticides, the mechanism of their transformation in the environment and the related information of their transformation products are still very scarce. Fluopyram is a kind of new pyridine ethyl benzamide fungicides of Bayer crop science and technology R & D, wide bactericidal spectrum, good control effect, has been registered and used in large-scale in China, but also widely used in other countries and regions in the world, but the environment on its transformation and transformation products other aspects of the research reported. In order to explore biological toxicity degradation, fluopyram in water and soil environment in the transformation mechanism and transformation products, this research the degradation behavior of the photochemical degradation mechanism of fluopyram water under laboratory conditions and in soil and fluopyram and its photochemical transformation products of biological toxicity. The main results are as follows: 1. fluopyram in 50 - 1 DEG C, pH 4, 7.2, 9 and 5 d dark cultivation under the condition of hydrolysis rate is less than 8.1%. According to the EPA712-C-08-012 issued by the United States Environmental Protection Agency, the hydrolytic half-life of fluopiridamide at 25 degrees centigrade was more than one year, and the hydrolysis was stable. Therefore, in the following photolysis study, the effects of hydrolysis can be ignored. 2. combined with the analysis results of LC-QqQ-MS/MS and LC-IT-TOF-MS/MS technology, fluopyram in high-pressure mercury lamp and xenon lamp in the water environment mainly produces three photochemical conversion products, respectively, 2,9- two (three trifluoromethyl) -6,7- two hydrogen pyridine ring [2,3-e][2] benzene imine -8 (5H) - Naphthalenone (TP 1), N- (2-[3- hydroxyl -5- three fluorine methyl -2- pyridine] ethyl) -2- three fluorine methyl benzamide (TP II) and N- (2-[5- three -2- fluorine methyl pyridine] ethyl) -2- three fluorine methyl benzamide (TP III), the highest amount of TP of more than 20%, TP II is about 9%, less than 1% of TP. By comparing under HPML, water, acetonitrile and 3% isopropanol water (v:v) differences in fluopyram photolysis rate and degradation product content, that TP I is the result of free radical intermediates of intramolecular dechlorination cyclization to form the TP II is an active oxygen formed by nucleophilic substitution, TP third is the formation of hydrogen abstraction reaction. TiO_2 under xenon lamp in catalytic fluopyram photochemical degradation mainly produces 6 products, LC-IT-TOF-MS/MS analysis showed that two of the product with TP I and TP II, the remaining four were 3- -5- three -2- chlorine fluorine methyl pyridine ethyl amine (TP IV), 3- -5- three -2- chlorine fluorine methyl ethyl pyridine formamide (TP V), N- (2-[3- -5- three -2- chlorine fluorine methyl ethyl] pyridine) -2- three fluorine -6- hydroxybenzamide (TP VI) and N- (2-[3- -5- three -2- chlorine fluorine methyl ethyl] pyridine) -2- three fluorine -4- hydroxybenzamide (TP VII), the formation of these ways the product is the main fracture of nucleophilic substitution and amide bond. Fe (III) under xenon lamp in sensitized fluopyram photochemical degradation mainly produces 7 products, also by LC-IT-TOF-MS/MS analysis showed that three of them with the same TP I - III, IV, TP three and TP TP VI and VII, the remaining one is 3- three -5- chlorine fluorine methyl acetamide (-2- pyridine TP, in addition to the VIII) way of forming pathways, including photo oxidation. 3. in the study of the high pressure mercury lamp and xenon lamp, Fe (III), Cu (II), (NO_3) -, humic acid, fulvic acid and riboflavin several of these natural water components, the effects of pH and TiO_2 light on the transformation of fluopyram. Under two kinds of light sources, the photolysis of fluopidamides under neutral conditions is faster than that in alkaline and acidic conditions, and the fastest is up to two times. Under high pressure mercury lamp, TiO_2 showed low concentration promotion effect and high concentration inhibition effect. The main components of water body showed inhibitory effect, of which riboflavin inhibition effect was the most obvious, up to 12.5 times, followed by humic acid, up to 10 times, and the rest was less than three times. In the under xenon lamp. TiO_2 showed the catalytic effect is obvious, the maximum catalytic effect of 17 times; (III) Fe showed sensitization effect significantly, up to 79 times; (II) and Cu (NO_3) - show to promote the effect of low concentrations and inhibitory effect of high concentrations of riboflavin, and two opposite; fulvic acid showed an inhibitory effect, up to two times; humic acid showed "S" type effect. 4. established fluopyram in three typical soils in China in residue analysis, method of average recovery rate is between 97-105%, the relative standard deviation between 3.9-11.6%, the limit of quantitation was 0.1mgkg~ (-1), the lowest detection limit of 5.0-7.5 gL~ (-1), matrix matched standard curve linear correlation coefficient greater than 0.99. With the degradation behavior of fluorine pyrazole amide to establish the analysis method of soil bacteria. The results showed that fluopyram under non sterile conditions under different soil water content and soil degradation half-life in the type 55.4-69.3 D in sterilized soil with different water and soil types in the degradation half-life of more than one year. This indicates that the soil types of the tested soil have no significant effect on the soil degradation of fluopidamides, and microbial degradation is the main way to degrade fluopiridamide in soil. Fluopiridamide is a more biodegradable pesticide based on the standard of the classification of the degradation grade of agricultural 15 in the soil. In addition, the main soil degradation products of fluopidamides were not found by contrasting the chromatograms of 0, 7, 30 and 60d. 5. the acute toxicity of fluopiridamide in the photodissociation solution under high pressure mercury lamp and xenon lamp was studied by the toxicity test of luminescent bacteria.
【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TQ450.1

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