RCEES OpenIR  > 中国科学院环境生物技术重点实验室
三唑类手性农药在食物链中的蓄积和传递
Alternative TitleAccumulation and Transfer of Chiral TriazolePesticides in Food Chain
陈锦辉
Subtype博士
Thesis Advisor李建中
2014-05
Degree Grantor中国科学院研究生院
Place of Conferral北京
Degree Discipline环境科学
Keyword食物链 三唑类农药 手性农药 安全性评价 蓄积 Food Chain Triazoles Chiral Pesticide Safety Evaluation Accumulation
Other Abstract      全球有现有 1600余种的农药,其中  30%以上的农药具有手性。由于农业生产的现代化,农药的使用量也越来越大。农药通过作物的吸收、残留、蓄积和传导,最终会影响到人类。对于手性农药,由于手性中心的存在,使得其手性异构体之间的生物活性、环境行为和环境毒理差异变得不同。但是,在使用上并未对这种差异进行区分,导致部分低活性、持久性和蓄积性的异构体进入了环境和生态,由此引发的安全问题也值得去详细的研究。
      本研究通过对手性三唑农药己唑醇、氟环唑、烯唑醇在食物链土壤-蚯蚓-鹌鹑中的行为进行了研究。在此过程中,建立了一种同时测定五种三唑类农药的十个异构体在土壤、蚯蚓、鹌鹑(血液、心脏、肝脏和肾脏)中的方法。该方法通过研磨、超声和离心对样品进行提取,用 GPC进行净化,利用  Chiralcel  OD-3R手性色谱柱,在超高效液相色谱-三重四级杆质谱上实现了十个异构体的分离。通过对方法的选择性、专属性、检测限、精密度、回收率、线性和方法的稳定性来进行了方法学的验证表明,这此方法满足试验的需求。
      建立了蚯蚓富集土壤中手性农药的方法,并用此方法研究了己唑醇、氟环唑、烯唑醇在蚯蚓中的富集特性。将蚯蚓(Eisenia foetida)暴露于三个不同浓度的三个不同手性三唑类农药中,结果表明,这三种农药的对应异构体在蚯蚓体内的蓄积和消除阶段都存在着立体选择性,他们的蓄积性表现出与 log KOW值成正比的关系。并且,蓄积性与暴露浓度密切相关,随着暴露浓度的增大,达到蓄积平衡状态所需要的时间也越短。从富集因子 BSAF值来看,   己唑醇和烯唑醇的富集因子随着暴露浓度的增加而增大,而氟环唑的富集因子则是随着暴露浓度的增加而下降。但这种选择性与农药的结构有密切的关系。随着与手性碳原子相连的基
团的活性的升高,在蓄积和消除阶段的立体选择性为烯唑醇>氟环唑>己唑醇。
       己唑醇、烯唑醇和氟环唑在鹌鹑(Coturnix coturnixs japonica)体内的代谢动力学表明,己唑醇和烯唑醇的代谢过程符合房室模型中的一室模型,而氟环唑的代谢则是一阶动力学模型。代谢半衰期的研究表明,与三种农药的结构有关,其半衰期也趋近于烯唑醇>氟环唑>己唑醇,其选择性代谢的程度也趋近于烯唑醇>氟环唑>己唑醇。R-烯唑醇在鹌鹑肝脏和肾脏有严重的蓄积。从鹌鹑的血液、心脏、肝脏和肾脏中,发现了己唑醇、烯唑醇和氟环唑的代谢物。依据这些代谢物出现的时间顺序和结构,推测了其在鹌鹑体内的代谢路径。
       以土壤、蚯蚓、鹌鹑组成典型的农田食物链,研究了三唑类手性农药烯唑醇、己唑醇和氟环唑在这条食物链中蓄积和传递。实验表明,三种手性三唑类农药在食物链中存在传递效应,传递的程度,随 log KOW值的增大,依次为烯唑醇>己唑醇>氟环唑。三种手性三唑类农药食物链中的蓄积具有选择性,选择性的显著性与结构中,与手性碳原子相连的基团的活性有关,依据活性的顺序烯唑醇>氟环唑>己唑醇,其在食物链中立体选择性的顺序为烯唑醇>氟环唑>己唑醇。在食物链中,随营养级的升高,立体选择性差异越来越明显。三种农药的代谢物随食物链营养级的升高,蓄积越来越严重。;       There are more than 1,600  pesticides using in the world, 30% of them  are chiral. Due to  the modernization  of agriculture,  pesticides became an  indispensable part  of planting. The applied  pesticide to farmland  is absorbed by crops,  transferred by food chain,  and  ultimately  affecte  humans.  For  chiral pesticides,  because  of  the  chiral centers, the  biological activity, the  environmental behavior  and toxicity are  different between the enantiomers.  The chiral pesticide is  usually used as racemic,  which may take the  low activity,  persistence  and accumulation  one of  the enantiomers  into the environment and ecosystem.  This will lead to  environmental pollution and biological extinction  in the  long run.  Thus,  the study  of  chiral pesticides  in  environment and ecosystem is very important.
      The  accumulation  and  transfer of  chiral  triazole  pesticides  in  the  food  chain soil-earthworms-quail was  studied. First, a  method for simultaneous  detection of  ten enantiomers    of    five    chiral    triazole    pesticides    (hexaconazole,epoxiconazole, diniconazole, myclobutanil,  tetraconazole) was  conducted on  liquid chromatography tandem  mass  spectrometry.  The  soil   sample,  earthworm  sample  and  quail  tissue sample wereextracted by acetonitrile byhigh  speed homogenizing, ultrasonic bath and centrifuging.Then  they were  clearnuped by  GPC.  At last  the  ten enantiomers  were separated   on  a   Chiralcel   OD-3R   chiral  column,   and   been  determined   on   an
Ultra-Performance  Liquid  Chromatography  tandem  mass  spectrometry.  The  LOD,
LOQ,  precision,  recovery  and  linearity of  methods  were  studied.  And  the  results
showed that this method was satisfied to the study.
      Earthworms(Eisenia    foetida)were exposed to three concentrations of hexaconazole, diniconazole  and epoxiconazole  enantiomer  (1 mg/kg,  10 mg/kg  and 25  mg/kg)  in  artificial  soil  (dry weight).  The  accumulation  and  elimination  were stereo selectivity. And the  changes of the EF (enantiomer fraction)  were closed to the activity  of  the group  bonded  to  chiral  center,  which  made the  stereo  selectivitive orderdiniconazole >  epoxiconazole  > hexaconazole.The  accumulation results  of  the  studies  were   closed   to  the   log  KOW   value  of   the  pesticide,   which  mad   the accumulation order  diniconazole >  hexaconazole > epoxiconazole.The  accumulation in  earthworms  was related  to  the  exposure  concentration.  The  steady state  of  the accumulation   came    fast   as   the    increasing   of   exposure   concentrations.    The bioaccumulation factors of  hexaconazole and diniconazole increasedas  the increasing of   exposure  concentrations,   and   the   bioaccumulation  factors   of   epoxiconazole decreased the increasing of exposure concentrations.
      The   pharmacokinetics    of   diniconazole,    hexaconazole   and    epoxiconazole enantiomers  in  quail  (Coturnix  coturnixs  japonica)  was   investigated.  The  results showed, pharmacokinetic  of diniconazole  and hexaconazole  fitted one-compartment model, while  epoxiconazole fitted first-order  kinetic model. The  studies showed that the the  half-life of  diniconazole, hexaconazole  and epoxiconazole enantiomers  were closely related to the the activity of the group bonded to  chiral center, which made the order of  diniconazole >  epoxiconazole >  hexaconazole. The R-diniconazole  showed high  risk   of  accumulation   in  quail  liver   and  kidney.The   metabolites  metabolic pathways of diniconazole, hexaconazole and epoxiconazolewere studied in this paper.
      The  accumulation  and  transfer of  triazole  chiral  pesticides  in  the  food  chain soil-earthworm-quail was  studied. It was  found that  stereoselective accumulationrisk increased as the extension of  the food chain. The accumulation order was  same to the log   KOW   order   of    diniconazole   >   hexaconazole   >epoxiconazole.The   stereo selectivitivity  in the  food  chain was  closed  to the  activity  of  the group  bonded  to chiral center, which showed an order of diniconazole > epoxiconazole > hexaconazole.The stereo  selectivitivityincreased as the increasing  of trophic level.  The metabolites of  the  three   chiral  pesticides  accumulated  strongly   in  the  food  chain,   and  also increased as the increasing of trophic level.
Document Type学位论文
Identifierhttp://ir.rcees.ac.cn/handle/311016/15715
Collection中国科学院环境生物技术重点实验室
Recommended Citation
GB/T 7714
陈锦辉. 三唑类手性农药在食物链中的蓄积和传递[D]. 北京. 中国科学院研究生院,2014.
Files in This Item:
File Name/Size DocType Version Access License
三唑类手性农药在食物链中的蓄积和传递-陈(6910KB) 开放获取--Application Full Text
Related Services
Recommend this item
Bookmark
Usage statistics
Export to Endnote
Google Scholar
Similar articles in Google Scholar
[陈锦辉]'s Articles
Baidu academic
Similar articles in Baidu academic
[陈锦辉]'s Articles
Bing Scholar
Similar articles in Bing Scholar
[陈锦辉]'s Articles
Terms of Use
No data!
Social Bookmark/Share
All comments (0)
No comment.
 

Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.