苯基吡唑类手性农药及代谢物在水环境中的立体选择性行为及污染修复研究

发布时间：2018-05-18 10:24

本文选题：手性农药 + 氟虫腈　；参考：《中国农业大学》2016年博士论文

【摘要】：随着社会的进步,农药的使用量也在逐年增多,据调查,手性农药的使用量在各种农药中大约占据了30%的份额。由于手性农药的不同对映体在生物体内存在明显的差别,从而导致被使用过的生物在各方面呈现出不同的特征,从而为环境毒理学的发展提供了依据。丁虫腈(flufiprole)作为使用时间较短的杀虫剂,其现在在社会上仍占据很大的市场。其目前主要是在外消旋体的基础上生产的。目前,就非靶标生物在对映体水平上的毒理与环境风险知之甚少。氟虫腈(fipronil)是90年代使用的一种杀虫剂,因其对水生生物具有较高的毒性,尽管这种杀虫剂已经停用,但是如果进行检测,在我们生活的环境中及生物体中依然可以找到其痕迹,因此,其潜伏期很长,特别是它在水中的代谢物对于水生态系统是个巨大的威胁。就目前而言,加强对手性农药的研究力度,由于其较强的毒性,尽可能在有限的范围内减少手性农药对于生态系统的破坏,确保生态系统的安全,这一研究课题在当下意义重大。本论文对丁虫腈、氟虫腈在水生生物体内的选择性富集、在生物体内各种循环等做了详细的调查;并深入探索环糊精对以上两种杀虫剂的影响。通过高效液相色谱手性固定相法,利用(R, R) Whelk-0 1型手性色谱柱、CHIRALCEL OD-H手性色谱柱、CHIRALPAK IB手性色谱柱对氟虫腈的两种手性代谢物(RPA200766和MB200761)进行了系统的拆分研究,优化了色谱分离条件,考察了热力学参数,探讨了手性识别机理。结果表明,两种代谢物对映体在优化的色谱条件下均可实现基线分离。研究丁虫腈、氟虫腈外消旋体及其代谢物(氟甲腈、硫化物、砜化物)对常见的几种代表性的水生生物(淡水藻、浮萍、河蚌、泥鳅)的立体选择性毒性。试验结果发现,丁虫腈和氟虫腈的R体的单体对几种水生植物的毒性要大于S体,与此相反的是,在水生动物的毒性测试中发现,S体的毒性要大。同时,三种代谢物的毒性都要高于母体化合物。建立了沉积物-水,沉积物-水-浮萍-河蚌的模拟水生态系统。研究结果发现,在沉积物-水中,整个暴露过程,水中大约70%的氟虫腈发生降解,半衰期为8.8天,EF值从0.49下降到0.44,有轻微的选择性行为。暴露初期16天,沉积物中的氟虫腈含量逐渐升高,最高浓度达到86.5 ng/g,随后浓度逐渐下降到53.3 ng/g.EF值从0.5下降0.38,说明沉积物中的微生物优先降解R体丁虫腈。同时也检测到氟虫腈的产生。第16天,fipronil在水中浓度达到最高为35.6ug/L,检测发现,氟虫腈EF值从0.5下降到0.37,说明代谢物S-氟虫腈优先生成且主要由沉积物中的微生物产生并逐渐释放到水中。在灭菌沉积物-水中,在90天的时间里,水中丁虫腈的含量只下降40%,同时只有少量的氟虫腈检出。与不灭菌不同的是,在灭菌沉积物中丁虫腈扩散到沉积物中在第11天达到峰值(132ng/g),随着时间的增长,氟虫腈的浓度没有明显下降,说明沉积物中的微生物在降解丁虫腈产生氟虫腈的过程中有重要的作用。同时,氟虫腈的检出要明显低于不灭菌的体系(4.6 ng/g),而且在水中和沉积物, 丁虫腈和氟虫腈EF值没有明显的偏离0.5,说明在灭菌条件下两个外消旋化合物没有明显的选择性发生。在沉积物-水中,整个暴露过程,水中大约60%的氟虫腈发生降解,半衰期为11.8天,暴露初期16天,沉积物中的氟虫腈含量逐渐升高,最高浓度达到86.5 ng/g,随后浓度逐渐下降到36.8 ng/g.同时也检测了三个主要的代谢物。第16天,sulfide在水中浓度达到最高为5.6ug/L,高于sulfone(11天4.9ug/L)和desulfinyl (7天3.2ug/L),大约在60天左右低于检出限。检测发现,代谢物在沉积物中浓度11天达到峰值分别为sulfide (7.5ng/g), sulfone (3.3ng/g), desulfinyl (5ng/g),说明代谢物主要由沉积物中的微生物产生并逐渐释放到水中。在灭菌沉积物-水中,在90天的时间里,水中氟虫腈的含量只下降32%,同时只有少量的desulfinyl检出。与不灭菌不同的是,在灭菌体系中氟虫腈扩散到沉积物中在第11天达到峰值(143ng/g),但随着时间的增长,氟虫腈的浓度没有显著地下降,说明沉积物中的微生物在降解氟虫腈的过程中有重要的作用。研究了氟虫腈及其代谢物在人工模拟水生态系统中的影响发现：氟虫腈在沉积物、浮萍、河蚌中存在立体选择性,在河蚌中主要是以S体形式存在,在浮萍和沉积物中主要以R体形式存在。产生可能的原因是两个异构体在河蚌中会发生单向转化,R-氟虫腈部分转化为S-氟虫腈,但S-氟虫腈不会转化为R-氟虫腈。运用手性毛细管气相色谱柱结合GC-ECD,考察了氟虫腈对映体及单体在河蚌、泥鳅体内的立体选择性富集和代谢行为。主要结论如下：氟虫腈在河蚌和泥鳅体内富集迅速,之后进入浓度逐渐降低并伴随重吸收的过程；氟虫腈在河蚌和泥鳅身体里经过一段时间的新陈代谢,呈现衰退的时间为四到八天；氟虫腈在映体的选择上主要体现在富集与循环的过程上。R体优先降解,通过单体试验发现,其可能的原因是由于酶的作用,是R体优先降解或单项转化成为S体氟虫腈最后,使用生物炭作为水中丁虫腈、氟虫腈的污染修复材料,对丁虫腈、氟虫腈在不同条件下的吸附效率进行了详细的试验,同时在添加生物炭的情况下测定了丁虫腈、氟虫腈及其代谢物对泥鳅的毒性。试验分别设定不同浓度,温度,pH,测定生物炭对丁虫腈、氟虫腈的吸附效率,考察生物炭运用到水中污染修复的可能性,从结果可以看出,pH和温度对生物炭吸附水中丁虫腈、氟虫腈的影响最大。即在酸性和较高温度条件下生物炭对丁虫腈和氟虫腈的消除效果最理想：试验在添加生物炭的情况下,测定了丁虫腈、氟虫腈及其代谢物对泥鳅的急性毒性。试验结果发现,生物炭的加入不仅降低了水中污染物的浓度,降低生物对水中污染的生物利用率,同时还降低了污染物对泥鳅的毒性。为修复水环境中两种农药及代谢物的污染提供理论依据。
[Abstract]:With the progress of society, the use of pesticides is increasing year by year. According to the investigation, the use of chiral pesticides occupies about 30% of all kinds of pesticides. Because the different enantiomers of chiral pesticides have obvious differences in living organisms, which leads to the different characteristics of the used organisms in all aspects, thus the environment is the environment. The development of toxicology provides a basis. Flufiprole, which is used as a shorter time insecticide, is still occupying a large market in society. It is now mainly produced on the basis of raceme. At present, little is known about the toxic and environmental risks of non target organisms at enantiomers. Fluonitrile (fipronil) is 9 An insecticide used in 0s, because of its high toxicity to aquatic organisms, although the insecticide has been disused, can be found in our living environment and living organisms, so it has a long latent period, especially its metabolites in the water are huge for the water ecosystem. At present, it is of great significance to strengthen the research on adversary pesticide, because of its strong toxicity, reducing the destruction of chiral pesticides to the ecosystem as much as possible and ensuring the safety of the ecosystem as much as possible. This thesis is of great significance at the moment. The effects of cyclodextrin on the two kinds of insecticides were investigated in detail, and the effects of cyclodextrin on the above two insecticides were explored. By HPLC, the two chiral metabolites (RPA200766) of fluonitrile (RPA200766) were used (R, R) Whelk-0 1 chiral chromatographic columns, CHIRALCEL OD-H chiral chromatographic columns and CHIRALPAK IB chiral chromatographic columns. The separation of the chromatographic separation conditions was optimized, the thermodynamic parameters were investigated, and the chiral recognition mechanism was discussed. The results showed that the two metabolites could be separated at baseline under the optimized chromatographic conditions. The study of nitrile, fluonitrile racemates and their metabolites (fluoromethonitrile, sulfides and sulfides) of the two metabolite enantiomers could be achieved. The stereoselective toxicity of several typical representative aquatic organisms (freshwater algae, duckweed, mussels, loach). The results showed that the toxicity of the R body of butylene and fluonitrile to several aquatic plants was greater than that of the S body. On the contrary, the toxicity test of the aquatic animals was found that the toxicity of the S body was large. At the same time, three metabolites were found. The results showed that about 70% of the fluonitrile in the water was degraded, the half-life was 8.8 days, the EF value decreased from 0.49 to 0.44, and there was a slight selective behavior. 16 of the initial exposure. The content of fluonitrile in the sediments increased gradually, the highest concentration reached 86.5 ng/g, and the subsequent concentration decreased to 53.3 ng/g.EF from 0.5 to 0.38, indicating that microbes in the sediments were preferred to degrade butylene nitrile. At the same time, the production of fluonitrile was also detected. Sixteenth days, the highest concentration of Fipronil in water was 35.6ug/L, detection, fluorine, and fluorine. The EF value of the nitrile decreased from 0.5 to 0.37, indicating that the metabolite, S- fluonitrile, was produced mainly by microbes in the sediments and gradually released into the water. In the sterilized sediments water, the content of butylitrile in water decreased only by 40% in 90 days, while only a small amount of fluonitrile was detected. The concentration of butylene nitrile in the sediment reached its peak in eleventh days (132ng/g). The concentration of fluonitrile did not decrease with time, indicating that the microorganisms in the sediments played an important role in the degradation of fluonitrile by butylene nitrile. At the same time, the detection of fluonitrile was significantly lower than that of the non sterilized system (4.6 ng/g). In water and sediments, the EF value of butibuitrile and fluonitrile did not significantly deviate from 0.5, indicating that the two racemes had no obvious selectivity under sterilization conditions. In the sediment water, about 60% of the fluonitrile in the water was degraded, the half-life was 11.8 days, and the fluonitrile in the sediments was contained in the sediments, and the fluonitrile contained in the sediments. The maximum concentration was up to 86.5 ng/g, the subsequent concentration decreased to 36.8 ng/g. and three major metabolites were also detected. Sixteenth days, the maximum concentration of sulfide in water was 5.6ug/L, higher than sulfone (11 days 4.9ug/L) and desulfinyl (7 day 3.2ug/L), which was about 60 days lower than the detection limit. The concentration of the product reached a peak of 11 days at sulfide (7.5ng/g), sulfone (3.3ng/g) and desulfinyl (5ng/g), indicating that the metabolites were mainly produced by microbes in the sediments and gradually released into the water. In the sterilized sediments water, the content of fluonitrile in water decreased only by 32% in 90 days, while only a small amount of desulfinyl was detected. In the sterilizing system, fluonitrile diffused into the sediments to reach a peak in eleventh days (143ng/g), but the concentration of fluonitrile did not decrease significantly over time, indicating that microbes in the sediments played an important role in the process of degrading fluonitrile. The study of fluonitrile and its metabolites in artificial simulation The effects of water ecosystem found that fluonitrile is stereoselective in sediments, duckweed, and mussels, mainly in the form of S body in mussels, and mainly in the form of R in duckweed and sediments. The possible reason is that two isomers can be converted into one direction in mussels, and R- fluonitrile is converted to S- fluonitrile. However, S- fluonitrile will not be converted to R- fluonitrile. Using chiral capillary gas chromatography column combined with GC-ECD, the stereoselective enrichment and metabolic behavior of fluonitrile enantiomers and monomers in mussels and loach were investigated. The main conclusions are as follows: fluonitrile is enriched in mussels and loach, and then the concentration is gradually reduced and accompanied by weight. The process of absorption; fluonitrile in the body of mussels and loach after a period of metabolism, showing a decline of four to eight days; the selection of fluonitrile enantiomers mainly reflected in the process of enrichment and circulation of.R body degradation, through the monomer test found that the possible reason for the effect of the enzyme, is the R body priority The solution or single item was converted into S body fluonitrile, and the biological charcoal was used as the pollution repair material of butylene nitrile and fluonitrile in water. The adsorption efficiency of butylene nitrile and fluonitrile under different conditions was tested in detail. At the same time, the toxicity of butafonitrile, fluonitrile and its metabolites to the loach were measured under the addition of biological carbon. Do not set different concentrations, temperature, pH, determine the adsorption efficiency of butachonitrile and fluonitrile by biological carbon, and investigate the possibility of biological charcoal used to repair the pollution in water. From the results, it can be seen that pH and temperature have the greatest influence on the adsorption of butachitrile and fluonitrile in water by biological carbon. The effect of nitrile removal is ideal: in the case of adding biological charcoal, the acute toxicity of butylene nitrile, fluonitrile and its metabolites to the loach was measured. The results showed that the addition of biochar not only reduced the concentration of pollutants in water, reduced the biological utilization rate of biological pollution to water, but also reduced the contamination of the loach. It provides a theoretical basis for restoring the pollution of two pesticides and metabolites in water environment.
【学位授予单位】：中国农业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：X592

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