除草剂乙草胺、异丙甲草胺的光降解及其致突变性

对两种常见的酰胺类除草剂乙草胺、异丙甲草胺的光降解进行了研究,采用Ames试验方法对母体及其光降解产物的致突变性进行了检验．结果表明,初始ｐＨ值的变化对这两种除草剂的光降解速率无明显影响,异丙甲草胺比乙草胺更易于发生光降解．乙草胺在光降解前后均表现出无致突变性;异丙甲草胺本身具有致突变性,在光降解过程中未表现出有其它致突变性物质产生．     

四种酰胺类除草剂对土壤酶活性的影响

在实验室控制条件下,研究了酰胺类除草剂丁草胺、乙草胺、丙草胺和异丙甲草胺在田间推荐用量下,对土壤过氧化氢酶活性和脱氢酶活性的影响.结果表明,培养初期,4种除草剂对2种酶活性有不同程度的抑制作用,土壤过氧化氢酶活性于第7d就很快恢复,而脱氢酶活性在13d后得以逐渐恢复.添加稻秆可使土壤酶活性提高,土壤脱氢酶比过氧化氢酶活性变化大.4种除草剂对土壤生态环境影响不大,稻秆还田有利于提高土壤中生化过程的活性,缓冲外来污染物对土壤生态的影响.     

酰胺类除草剂与四种杀虫剂对蚯蚓的联合毒性

采用滤纸接触法测定了2种酰胺类除草剂和4种常用杀虫剂及其混剂对赤子爱胜蚯蚓(Eisenia fetida)的室内毒性,并用毒性单位法评价混剂的联合毒性效应.结果表明,6种农药对赤子爱胜蚯蚓的毒性依次为阿维菌素＞克百威＞毒死蜱＞三唑磷＞乙草胺＞丁草胺,96h致死中浓度分别为0.800,3.481,8.213,10463,12.580,29.910μg/cm2;乙草胺分别与克百威和三唑磷按毒性单位11和14混用,使克百威的蚯蚓毒性分别增强9.5和4.5倍,三唑磷的蚯蚓毒性分别增强5.5和4.4倍,丁草胺与三唑磷按毒性单位11和14混用,使三唑磷的蚯蚓毒性分别增强6.7和4.8倍.其他混用组合未见明显的增毒作用.     

ASE-GC/MS同时测定土壤中8种酰胺类除草剂

通过优化加速溶剂萃取(ASE)条件、固相小柱净化(SPE)条件和气相色谱质谱(GC/MS)仪器分析条件,建立了"ASE提取-SPE净化-GC/MS分析"同时测定土壤中敌稗、甲草胺、乙草胺、丙草胺、丁草胺、杀草丹、异丙草胺和异丙甲草胺8种酰胺类除草剂残留量的分析方法。土壤样品经正己烷∶丙酮(1∶1)提取,提取液浓缩后经固相小柱净化,气相色谱质谱测定,内标法定量。研究结果表明:8种酰胺类除草剂在0.1~6.0 mg/L范围内线性良好,相关系数在0.995以上,方法检出限在5.0×10~(-3)~9.2×10~(-3)mg/kg之间,对实际土壤样品进行低、中、高浓度分别为0.02、0.05和0.5 mg/kg的加标测定,平行分析(n=6)的相对标准偏差在3.6%~12.5%之间,酰胺类除草剂的平均回收率在64.8%~101.7%之间。该方法灵敏度高、快速准确,适用于土壤中酰胺类除草剂的定性和定量检测,能为批量土壤样品的检测提供科学的方法。     

L-半胱氨酸对酰胺类除草剂的离体脱氯反应与机制

研究了L-半胱氨酸与酰胺类除草剂的反应动力学、热力学及其机制.结果表明,L-半胱氨酸促进酰胺类除草剂的降解,该反应遵循二级动力学方程;除草剂降解速率同除草剂分子的亲电常数线性相关,降低顺序为甲草胺(kL-cysteine=7.65×10-3mol/(L×s))>乙草胺(kL-cysteine=7.23×10-3mol/(L×s))>丁草胺(kL-cysteine=6.01×10-3mol/(L×s))>S-异丙甲草胺(kL-cysteine=2.15×10-3mol/(L×s)),这与其土壤和高效菌降解速率顺序相一致;产物的质谱鉴定表明,L-半胱氨酸取代除草剂分子中氯原子.表明该反应为双分子亲核取代脱氯反应.热力学分析显示,该反应为焓控反应.除草剂间降解速率的差异性由熵变控制,且除草剂的降解速率与反应熵变(ΔS)具有良好的线性关系,ΔS数值越负,除草剂的降解速率越小.分子中N原子上的醚键取代基支链结构及链长度对反应速率影响较大,而芳环取代基结构没有明显影响.     

酰胺咪嗪光降解效能与机制及其影响因素研究

以氙灯为模拟光源,研究了酰胺咪嗪（carbamazepine,CBZ）在纯水中的光降解效能与机制,并考察了硝酸根离子（NO3-）、碳酸氢根离子（HCO3-）和腐殖酸（HA）对其光降解速率的影响.结果表明,纯水中CBZ的光降解符合假一级反应动力学;在光强为1 200 mW.cm-2、CBZ初始浓度为200μg·L-1时,CBZ的光降解速率常数为0.028 7 min-1,半衰期为24.15min;纯水中CBZ的去除是以自敏化光降解反应为主,其中单线态氧（1O2）参与的自敏化光氧化反应贡献率较大,为75.3%,而羟基自由基（.OH）的贡献率较小,为5.6%;在本试验条件下,NO3-、HCO3-以及HA浓度的增加都会对CBZ的光降解过程产生抑制,其中NO3-的抑制作用最为明显,当加入的NO3-浓度为0.5 mmol·L-1时,CBZ的半衰期延长为433.22 min,约为不加NO3-时的18倍.     

几种消毒剂对饮水致突变活性的影响

本研究应用Ａｍｅｓ致突变试验对武汉东湖水分别经氯、二氧化氯和臭氧消毒处理后的致突变活性进行了检测与比较。结果表明：东湖水以及臭氧消毒处理水样未呈现致突变性,氯与二氧化氯处理的水样致突变性检测结果为阳性,这３种消毒剂处理的各水样致突变比活性强度顺序由强至弱依次为氯〉二氧化氯〉臭氧;同时对东湖水用高锰酸钾预处理,以降低氯化消毒饮水致突变活性的效果也进行了比较,结果发现用高锰酸钾预处理东湖水,可降低氯化     

鲁奇低温煤焦油的致突变性及致突变性组分的鉴定

煤焦油样品经提取分离为酸性、碱性和中性组分,后两组分再经硅胶柱制备色谱分作B_1—B_33个级分和N_1—N_66个级分.Ames试验表明,B_2级分致突变活性最高.该级分经HPLC进一步分级表明,其中d、f级分具较高的致突变性经HRGC、HRGC-MS分析,分别从d级分鉴定出苯并喹啉等60多种氮杂多环芳烃,f级分鉴定出氮杂苯并芴等40多种氮杂多环芳烃.     

作物植株残体还田土壤对除草剂的截留作用

加入成熟作物植株残体还田的土壤（简称秸秆还田土壤）与自然土壤的土柱淋洗对比实验，研究了玉米秸秆还田土壤对除草剂乙草胺和阿特拉津的截留作用以及水稻秸秆还田土壤对丁草胺的截留作用。结果表明，作物秸秆还田土壤对所研究的三种除草剂有明显的截留作用，在土桩的最上部10cm内，秸秆还田土壤对乙草胺、丁草胺和阿特拉津的截留量分别是自然土壤对其截留量的1.33、1.77和1.88倍。     

扬中市地表水的致突变性研究

本研究诮蚕豆根尖微枋试验对扬中市不同水体的遗传毒物污染状况进行了初步调查。结果表明，扬中市水体的遗传毒物污染集中在汇集了乡镇工业废水和生活污水的排污河道和死水沟塘。各主要河道及通江闸口基本没有污染。除新坝大桥处，各样点底泥浸担液的微枋率均高于相应原水样微核率。     

Photodegradation of acetochlor in water and UV photoproducts identified by mass spectrometry

The sunlight photodegradation half-lives of 20 mg/L acetochlor were 151, 154 and 169 days in de-ionized water, river water and paddy water, respectively. When exposed to ultraviolet (UV) light, acetochlor in aqueous solution was rapidly degraded. The half-lives were7.1, 10.1, and 11.5 min in de-ionized water, river water and paddy water, respectively. Photopreduets of acetochlor were identified by gas chromatography/mass spectrometry(GC/MS) and found at least twelve photoproducts resulted from dechlorination with subsequent hydrtrxylation and cyclization processes. The chemical structures of ten photoproducts were presumed on the basis of mass spectrum interpretation and literature data. Photoproducts are identified as 2-ethyl-6-methylaniline; N, N-diethylaniline ; 4, 8-dimethyl-2-oxo- 1,2,3,4- tetrahydroquino-line; 2-oxo-N-(2-ethyl-6-methylphenyl)-N-(ethoxymethyl) acetamide; N-(ethoxymethyl)-2‘-ethyl-6‘-methylformanilide; 1-hydroxyaeetyl-2-ethoxyl-7-ethylind ole; 8-ethyl-l-ethoxymethyl-2-oxo-1, 2, 3, 4-tetrahydroquinoline; 4, 8-dimethyl-l-ethoxymethyl-2-oxo-1, 2, 3, 4-tetrahydroquinoline; 2-hydroxy-2‘-ethyl-6‘-methyl-N-(ethoxymethyl) acetanilide and a compound related to acetochlor. The other two photoproducts were detected by GC/MS although their chemical structure was unknown.     

Photodegradation mechanism of deltamethrin and fenvalerate

To understand the degradation and environmental fate of pyrethroids, the process of their photodegradation under simulated natural conditions was investigated. The results showed that the degradation process follows first-order kinetics. The degradation intermediates were identified with gas chromatography-mass spectrometry. A plausible mechanism was discussed to explain the process. Several influences on degradation process were investigated and reported such as the e ects of initial concentration of pyrethroids, total time of light irradiation, solvents, and light source, as well as the e ect of a few substances that exist in the environment. This study could be a good reference for the degradation of pyrethroids in practical circumstances.     

十二烷基苯磺酸钠对异丙草胺光解体系的影响

研究了不同浓度的阴离子表面活性剂十二烷基苯磺酸钠(SDBS)对除草剂异丙草胺在水溶液中光解的影响。结果表明,表面活性剂不直接参与异丙草胺的光反应;在ρ(SDBS)小于其临界胶束浓度(CMC)时,SDBS对异丙草胺的光反应有微弱抑制作用,而ρ(SDBS)大于其CMC时,SDBS胶束的形成对异丙草胺的光反应有加速的趋势。推测是由于ρ(SDBS)在达到CMC之前,对光解的影响以光吸收作用为主,对异丙草胺光解有一定的抑制;而达到CMC后,胶束对异丙草胺有富集作用,胶束内部类似有机相的环境,利于异丙草胺光反应,此时SDBS对光解的作用就以加速光解为主。      

游离羟基及表面活性剂对乙草胺光解的影响

以高压汞灯为光源,以p-亚硝基-N,N-二甲基苯胺(PNDA)作为·OH自由基的探针,研究了H2O2及表面活性剂0206-B(苯乙烯苯酚聚氧乙烯醚和十二烷基苯磺酸钙混剂)对除草剂乙草胺在水中间接光解作用的影响.结果表明,H2O2对水中乙草胺具有光敏化降解作用,其敏化作用效应与·OH有关;而0206-B对乙草胺具有光猝灭降解作用,光猝灭降解作用效应与0206-B减少水溶液中的·OH自由基含量有关.乙草胺直接光解与H2O2作用的乙草胺间接光解相同的产物有Rf(比移值)为0.12、0.52、0.61、0.72的化合物;H2O2敏化降解抑制了乙草胺直接光解产物Rf为0.04、0.10、0.18、0.21、0.79的化合物产生,但促进乙草胺间接光解Rf为0.45、0.66的新光解产物生成.     

超高效液相色谱-串联质谱法同时检测水中16种芳氧苯氧丙酸酯类除草剂

采用固相萃取-超高效液相色谱-串联质谱法(UPLC-MS/MS)通过对固相萃取柱、洗脱液、流动相等的优化,建立了水中16种芳氧苯氧丙酸酯类(APP)除草剂的分析方法。确定以Oasis HLB为固相萃取柱、丙酮-正己烷(1∶1,V/V)为淋洗液、水-乙腈(3∶7,V/V)为流动相进行水样预处理,在最优条件下,各目标物在水中的回收率均达到74.5%~124.9%,相对标准偏差为4.2%~9.6%,线性范围为1~2 000μg/L,各目标物标准品在UPLCMS/MS系统中有效的线性相关系数(R2)达到0.998以上。该方法具有检测限低、回收率高等优点,经实际样品测试,可适用于水中16种APP类除草剂的同时检测。     

Adsorption of chloroacetanilide herbicides on soil and its components Ⅲ. Influence of clay acidity, humic acid coating and herbicide structure on acetanilide herbicide adsorption on homoionic clays

Adsorption of chloroacetanilide herbicides on homoionic montmorillonite, soil humic acid, and their mixtures was studied by coupling batch equilibration and FT-IR analysis. Adsorption isotherms of acetochlor, alachlor, metolachlor and propachlor on Ca2 + -, Mg2 + -. Al3 + -and Fe3 + -saturated clays were well described by the Freundlich equation. Regardless of the type of exchange cations, Kf decreased in the order of metolachlor ＞ acetolachlor ＞ alachlor ＞ propachlor on the same clay. FT-IR spectra showed that the carbonyl group of the herbicide molecule was involved in binding, probably via H-bond with water molecules in the clay interlayer. The type and position of substitutions around the carbonyl group may have affected the electronegativity of oxygen, thus influencing the relative adsorption of these herbicides. For the same herbicide, adsorption on clay increased in the order of Mg2+ ＜ Ca2+ ＜ Al3+ ≤ Fe3+ which coincided with the iucreasing aciditv of homoionic clays. Acidity of cations may have affected the protonation of water, and thus the strength of H-bond between the clay water and herbicide. Complexation of clay and humic acid resulted in less adsorption than that expected from independent adsorption by the individual constituents. The effect varied with herbicides, but the greatest decrease in adsorption occurred at a 60:40 clay-to-humic acid ratio for all the herbicides. Causes for the decreased adsorption need to be characterized to better understand adsorption mechanisms and predict adsorption from soil compositions.     

土壤及铝氧化物吸附氯磺隆和苄嘧磺隆动力学研究

用间歇法研究了红壤和人工合成的铝氧化物吸附除草剂(氯磺隆、苄嘧磺隆)的动力学特性。结果表明:土壤和氧化物对除草剂的吸附均在较短的时间内达到平衡。用五种模型对土壤和氧化物的吸附动力学过程进行了描述,其中最优模型是一级动力学方程。两种除草剂在两种供试样品中的吸附量均有差别。     

Adsorption of chloroacetanilide herbicides on soil and its components Ⅲ. Influence of clay acidity, humic acid coating and herbicide structure on acetanilide herbicide adsorption on homoionic clays

Adsorption of chloroacetanilide herbicides on homoionic montmorillonite, soil humic acid, and their mixtures was studied by coupling batch equilibration and FT-IR analysis. Adsorption isotherms of acetochlor, alachlor, metolachlor and propachlor on Ca²⁺-, Mg²⁺ -. Al³⁺ -and Fe³⁺ -saturated clays were well described by the Freundlich equation. Regardless of the type of exchange cations, Kf decreased in the order of metolachlor ＞ acetolachlor ＞ alachlor ＞ propachlor on the same clay. FT-IR spectra showed that the carbonyl group of the herbicide molecule was involved in binding, probably via H-bond with water molecules in the clay interlayer. The type and position of substitutions around the carbonyl group may have affected the electronegativity of oxygen, thus influencing the relative adsorption of these herbicides. For the same herbicide, adsorption on clay increased in the order of Mg²⁺ ＜ Ca²⁺ ＜ Al³⁺ ≤ Fe³⁺ which coincided with the iucreasing aciditv of homoionic clays. Acidity of cations may have affected the protonation of water, and thus the strength of H-bond between the clay water and herbicide. Complexation of clay and humic acid resulted in less adsorption than that expected from independent adsorption by the individual constituents. The effect varied with herbicides, but the greatest decrease in adsorption occurred at a 60:40 clay-to-humic acid ratio for all the herbicides. Causes for the decreased adsorption need to be characterized to better understand adsorption mechanisms and predict adsorption from soil compositions.