【作者】 于萍萍；

【导师】 张进忠；

【作者基本信息】 西南大学 ， 环境科学， 2008， 硕士

【摘要】 近年来,茶叶的卫生质量是人们关注的焦点问题,也是影响我国茶叶在国际贸易中竞争力的主要因素。茶叶的安全卫生已经在国际贸易中成为一种技术壁垒。氰戊菊酯、甲氰菊酯和噻嗪酮（优乐得）是当前我国出口茶叶超标排列前三位的农药。如何用科学的方法,快速、准确地检测出茶叶中农药的残留量,对正确使用农药,提高茶叶质量,扩大出口起着重要作用。本文首先调查了西南地区主要茶园土壤和茶叶中菊酯类农药的污染背景,采用单因子污染指数和内梅罗污染指数进行了茶叶中的菊酯类农药污染评价,分析了茶园土壤和茶叶的卫生质量状况,为该地区茶叶产业的健康发展获得了基础数据。在此基础之上,选定噻嗪酮、甲氰菊酯、氰戊菊酯三种农药为研究对象,监测在茶树不同培养期菊酯类农药在茶叶中吸收与累积的动态过程,研究茶叶对它们的残留与代谢特征,从而为科学地认识西南地区茶叶中菊酯类农药的残留问题和防治茶叶中菊酯类农药污染提供理论依据。本文获得了如下的研究成果:1.茶园中农药污染背景调查:西南地区主要茶园的茶叶中噻嗪酮、甲氰菊酯和氰戊菊酯3种农药的含量都在相应的质量标准范围内,单因子污染指数和Nemerow污染指数均小于1.0。其中,缙云山、贵州的茶园土壤没有受到农药污染,可以考虑发展无公害茶园基地;福鼎、永川的茶园土壤中3种农药都有检出,要注意农药的使用,避免农药残留量过大,影响茶叶产品的质量:乐山、北碚茶园要注意氰戊菊酯的使用。2.水培实验研究茶叶中菊酯类农药的残留与累积的动态特征:通过水培试验培养茶树,研究了在不同培养期茶叶中噻嗪酮、甲氰菊酯和氰戊菊酯农药残留与降解的动态特征。结果表明:在茶叶中农药的残留量随喷施农药的浓度的增加而增加,其中噻嗪酮最容易残留,甲氰菊酯次之,氰戊菊酯残留最少。3.盆栽实验研究菊酯类农药的残留与代谢过程:通过盆栽实验,研究了在不同培养期茶叶中噻嗪酮、甲氰菊酯和氰戊菊酯农药残留与降解的动态特征。结果表明:随着培养时间的增加,农药在茶叶中的降解率相应增大,其中氰戊菊酯降解最快,噻嗪酮和甲氰菊酯的降解率相近。4.水培实验和盆栽实验结果均发现:三种农药在茶叶中的残留均符合一级动力学方程,可用C_t=C₀e^-kt。表示,式中t为降解时间,k为农药的降解速率常数,C₀为农药的初始浓度,C_t为农药在时刻的浓度。其中,氰戊菊酯的降解速率常数最大,其次为甲氰菊酯,噻嗪酮最小。同时也获得了三种农药的半衰期,从高到低的顺序依次为噻嗪酮、甲氰菊酯和氰戊菊酯。更多还原

【Abstract】 In recent years,the hygiene quality of tea is the focus of attention,and also is the main factor affecting the competitiveness in the international trade.In recent years,the health and safety of tea has become a kind of technical barriers in international trade.Now,buprofezin, fenpropathrin and fenvalerate are the three excess-standard pesticides in export tea of our country.How to use scientific methods to quickly and accurately detect pesticide residues in tea plays an important role in the proper use of pesticides,improvement of the quality of tea,and enlargement of the export.In this thesis,the pollution background of pyrethrins was investigated in tea-garden soils and teas in the southwest region of China,the pollution status of pyrethrins were evaluated using the single-factor pollution index and Nemerow pollution index,and the health quality of tea-garden soils and teas were analyzed.Thus,the basic data were obtained for the sustainable development of tea industry in the above region.Based on the background investigation,the three pesticides including buprofezin,fenpropathrin and fenvalerate were selected as research objects,and the dynamic characteristics of residue and metabilosm of them in tea were studied. This study can provide theoretics foundation to scientically know the residual problem of pyrethrins in tea in southwest region and prevent the pollution of pyrethrins in tea.The results were summarized as follows.1.The background investigation of pyrethrins in tea-gardens:the contents of three kinds of pyrethrins in tea in southwest region were in the scope of quality standards,with the single-factor pollution indices and Nemerow pollution indices of less than 1.0.No pesticide pollution was found in the tea-gardens in Mount Jinyun and Guizhou,and these tea-gardens could be developed as the bases with no public hazard.However,the three pesticides were detected in the tea-gardens in Fuding and Yongchuan,and the use of pesticides must be payed attention to avoid highly residual amounts,and affect the quality of tea.In addition,the use of fenvalerate must be payed attention in the tea-gardens in Leshan,Beibei.2.The dynamic characteristics of residue and metabolism of pyrethrins in tea at different culture times were studied by using liquid cultivation.The results showed that the residual amounts in tea increased with the concentrations of the sprayed pesticides increasing.Among them,buprofezin was the easiest one to be residual,and then fenpropathrin,fenvalerate was the last one.3.The process of residue and metabolism of pyrethrins in tea was studied by potted cultivation in different culture period.The results showed that the degradation rates of the three pesticides in tea increased with culture time increasing.Among them,fenvalerate was degraded the fastest,and the degradation rates of buprofezin and fenpropathrin were close.4.From liquid cultivation and potted experiments,it can be found that the residual amounts of the three pestcides in tea could be described as a first order dynamic equation,i.e.C_t = C₀e^-kt, where t is the culture time,k is the degradation rate constant of pesticide,C₀ is the initial concentration of pesticide,and C_t is the concentration of pesticide at t.Among them,the degradation rate constant of fenvalerate was maximum,and then fenpropathrin,and that of buprofezin was minimum.The half-lives of the three pesticides were also obtained,with the order of buprofezin,fenpropathrin and fenvalerate from high to low.更多还原