【作者】 马辉；

【导师】 张东海；

【作者基本信息】 石河子大学 ， 农业昆虫与害虫防治， 2008， 硕士

【摘要】 硫丹是目前国内唯一用于防治棉铃虫、棉蚜的有机氯杀虫剂,为了能够充分发挥硫丹在生产中的农药保护作用,评价硫丹在棉花上的残留情况以及对土壤环境的影响显得尤为重要。本试验是以35%硫丹乳油为研究对象进行了一年两地的残留分析试验。建立了硫丹在棉叶、棉籽和土壤中的残留分析方法,根据田间试验结果,推荐出35%硫丹乳油在棉花中防治棉铃虫、棉蚜的合理使用准则。硫丹的残留分析方法研究:以棉叶、棉籽和土壤为研究材料,采用气相色谱法,通过实验对不同残留分析方法进行了比较。结果表明:棉叶和棉籽样品用乙腈、氟罗里硅土固相萃取小柱净化,后经气相色谱检测。在棉叶、棉籽中的添加回收率分别为82.0%～95.7%和82.9%～95.6%,变异系数分别为6.9%～13%和3.2%～20%。土壤样品用丙酮提取,石油醚液-液萃取,旋转蒸发仪浓缩后,经氟罗里硅土固相萃取小柱净化,后经气相色谱仪检测,硫丹在土壤中的添加回收率在87.6%～104%之间,变异系数在6.2%～21%之间。在实验过程中,对样品前处理和色谱分离条件进行了详细的研究和优化,最终确证以上方法简便、准确、快速、净化效果好,满足农药残留分析的要求。消解动态试验:按照一次施药多次采样的方法对35%硫丹乳油在棉叶和土壤中的消解动态进行研究。结果表明:在石家庄市,硫丹在棉叶中的消解动态方程为C_T=33.6e^-0.117T,在土壤中的消解动态方程为C_T=2.38e^-0.0348T,相关系数分别为-0.9491和-0.8368,消解半衰期分别为5.92d和19.92d。在长沙市,硫丹在棉叶和土壤中的消解动态方程分别为C_T=31.3e^-0.116T和C_T=9.20e^-0.0460T,相关系数分别为-0.8597和-0.9521,消解半衰期分别为5.99d和15.07d。硫丹在不同时期在棉叶和土壤中的消解动态均符合一级动力学反应模式,都具有较高的相关性。硫丹在棉叶中的消解速率较土壤中快,石家庄地区的消解速率也不同于长沙地区。最终残留试验:在945a.i.g/hm²、1890a.i.g/hm²的施药水平下,施药3次、4次,每次施药间隔期为14d,施药后距采收间隔期为7d,最终残留试验结果表明:在石家庄市,硫丹在棉叶中的最终残留量为0.492-13.2mg/kg,在土壤中的最终残留量为0.196-0.851mg/kg。在长沙市,硫丹在棉叶中的最终残留量为0.421-1.58mg/kg,在土壤中的最终残留量为0.114-0.258mg/kg,在棉籽中两地均未检出有硫丹残留,从数据分析来看:硫丹的最终残留量与施药浓度、施药次数呈正相关,施药浓度越高,施药次数越多,残留量越高;与采收间隔期呈负相关,且棉叶中的残留量高于土壤中。联合国粮农组织（FAO/WTO）制定其标准为:硫丹在棉花籽中的最高残留限量（MRL）为1.0mg/kg。我国的推荐性国家标准:硫丹在棉籽中的最高残留限量为1.0mg/kg。由硫丹在棉花中的最终残留试验结果,我们可以看出35%硫丹乳油用于棉花害虫防治的过程中,按推荐剂量945a.i.g/hm²和加倍剂量1890a.i.g/hm²使用,其残留量均低于限定标准,在棉籽中均没有检测出硫丹的残留。因此,根据本研究,暂建议在棉花的生长时期,35%硫丹乳油使用剂量为推荐剂量945a.i.g/hm²和加倍剂量1890a.i.g/hm²,施药3到4次且最大残留限量为1.0mg/kg,在棉花中的安全间隔期为14d,在此安全间隔期内施药对环境安全,收获棉花时其棉籽中未检出有硫丹残留,其残留量满足残留标准要求,是安全的。更多还原

【Abstract】 As a high efficiency Organochlorine insecticide, endosulfan is only pesticide that use in prevention cotton bollworm and cotton aphid. In agricultural production, endosulfan will take a key role in the future. In order to use endosulfan in science way, evaluate the residue level in cotton and affect in soil. In this paper, one-year residue-assignment of endosulfan was carried out in different Places. A method was studied for the analysis of endosulfan residue in cotton, cottonseed and soil and 35% endosulfan EC had been recommended to control cotton bollworm in cotton according to the results of field experiment.Residue analysis methods research on endosulfan, gas chromatography method has been used in cotton、cottonseed and soil, different methods have been compared by experiments. The results show, cotton and cottonseed sample were extracted with acetonitrile, after the extract was cleaned up with a Florisil column, endosulfan was analyzed by GC, the average recoveries of cotton ranged from 82.0% to 95.7%, the C.V was between 6.9% to 13%. The average recoveries of cottonseed ranged from 82.9% to 95.6%, the C.V was 3.2% to 20%. Soil sample was extracted with acetone, LLE by petroleum ether, the average recoveries of soil ranged from 87.6% to 104%, the C.V was between 6.2% to 21%. The pre-treatment method of samples and the chromatographic conditions of the analysis were critically examined in experiment, the above method were confirmed for its easier, exacter, faster and being better purification effect.Studies on residual degradation dynamics of endosulfan in cotton and soil were according to spraying once, sampling time after time. The results showed: in ShiJiaZhuang, the degradation curve equations of endosulfan in cotton and soil in different term and the degradation dynamics were: C_T=33.6e^-0.117T and C_T=2.38e^-0.0348T. The correlation coefficients were -0.9491 and -0.8368 and the half-lives were 5.92 and 19.92 days. In ChangSha, the degradation dynamics were: C_T=31.3e^-0.116T and C_T=9.20e^-0.0460T. The correlation coefficients were -0.8597 and -0.9521. The half-lives were 5.99 and 15.07 days. Residual degradation dynamics of endosulfan in different term in cotton and soil were all accorded with C=Coe-kt and all had high relativity. The degradation speed of endosulfan in cotton is fast than in soil and the degradation speed in ShiJiaZhuang is different from ChangSha.The final residues experiment: cotton were treated three and four times and interval of 14 days with the dosages of 945a.i.g/hm² and 1890a.i.g/hm² during the growing season of cotton. The application after harvest interval was 7 days. The result of final residues of endosulfan showed: in ShiJiaZhuang, the final residues of endosulfan in cotton were 0.492mg/kg to 13.2mg/kg. In cottonseed was not detectable, in soil was 0.196mg/kg to 0.851mg/kg. In ChangSha, the final residues of endosulfan in cotton was 0.421mg/kg to 1.58mg/kg, in cottonseed was not detectable,in soil was 0.114mg/kg to 0.258mg/kg. According to these data: there were positive relation between residue and consistence as well as times sprays for, the high of the concentration in usage and the more times of applying, the residual are more higher, and negative relation residue and the days from last application to harvest and the residual in cotton is above soil.Refer to FAO/WTO MRL endosulfan in cottonseed that MRL is 1.0mg/kg and our government prescribe the MRL in cottonseed is 1.0mg/kg. The result of the final residual showed: 35% endosulfan EC used on cotton is safe. The dosage of endosulfan applied on cotton is 945a.i.g/hm² to 1890a.i.g/hm² are all below limit standard and endosulfan in cottonseed was not detectable. So based on the result of the trial, we suggest that the dosage of endosulfan applied on cotton be 945a.i.g/hm² or 1890a.i.g/hm² and three or four times during the cotton growing period and MRL be 1.0mg/kg in cottonseed. The safe interval period should be 14 days. In this safe period, endosulfan is safe to environment and when harvest that the residual of cottonseed was not detectable and suitable the residual standard.更多还原