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1.
百菌清(chlorothalonil)在水中的光化学降解   总被引:10,自引:0,他引:10  
研究了光源种类、溶液pH、水温和表面活性剂对百菌清光解的影响.结果表明,百菌清水溶液在高压汞灯、紫外灯和太阳光照射下的光解半衰期分别为22.4、82.5和123.8 min;在太阳光和高压汞灯照射下,百菌清在碱性溶液中比中性和酸性溶液中光解快;随着水温的升高,百菌清光解速率加快,水温平均每升高10 ℃,光解速率大约增大1倍.表面活性剂十二烷基磺酸钠、Tween 60和Span 20对百菌清的光解表现出显著的光敏化效应,十六烷基三甲基溴化铵对百菌清光解有强烈的光猝灭效应.  相似文献   

2.
丁草胺在不同类型水中的光化学降解   总被引:29,自引:4,他引:25  
研究了除草剂丁草胺在氙灯、高压汞灯光照下的光解动态.结果表明,丁草胺在氙灯光照作用下,其光解速率为纯水>河水>塘水>稻田水;丁草胺在氙灯光源下的光解速度比高压汞灯下低;其光解率与浓度(剂量)呈反相关;充N2脱O2使丁草胺的光解速度减缓.  相似文献   

3.
在大棚和露地栽培条件下,研究了不同浓度的毒死蜱灌根施药后土壤和韭菜中毒死蜱的残留与降解动态.结果表明:韭菜中毒死蜱的降解速度比土壤中快,平均半衰期分别为3.41 d和7.40 d;在大棚和露地栽培条件下,韭菜中毒死蜱的降解速率差异不大,平均降解半衰期分别为3.37和3.44 d.施药灌根后第21天,韭菜中毒死蜱的残留量(0.021 ~0.102mg·kg-1)基本低于GB 2763-2005规定的最大残留限量标准(≤0.1 mg·kg-1).新生韭菜中仍残留少量毒死蜱,但明显低于药后第一次刈割.土壤中残留的毒死蜱对韭菜中的农药残留量有显著影响.  相似文献   

4.
采用HPLC检测法研究5,脱氧腺苷钴胺素和甲基基钴胺素的水溶液在不同光源及不同照度下的光解情况,结果表明随着光能量的增加光解速度加快。利用脱氧腺苷钴胺素的光解性质,探索了一种检测发酵液中维生素B12含量的新方法。将含有钴胺素的细胞破碎液完全光解后,测定光解后的产物羟基钴胺素,以此来确定维生素B12产量。此方法简便快速、重复性好,可应用于发酵生产维生素B12的各个环节。  相似文献   

5.
了解植物病毒在不同水体与温度条件下的灭活规律具有重要的理论与实际意义。本文以典型植物病毒烟草花叶病毒(TMV)为模型,比较了其在不同温度条件下,在闽江水、自来水、生活污水、微孔滤膜过滤除菌污水及超纯水中的灭活动力学。结果显示,温度是导致TMV灭活的重要因素,水温升高,病毒灭活速率加快;此外,某些水质因子也影响TMV的灭活效率,其中可溶性盐的存在及其含量对TMV的灭活会因所处的环境不同而异;某些微生物或代谢产物对植物病毒TMV具有灭活作用,而能生化降解的有机质加速TMV灭活可能是通过促进水体中的微生物增殖而起作用。  相似文献   

6.
为了明确温度对杀虫剂毒杀作用的影响,本文研究了5个温度梯度(22℃、25℃、28℃、31℃和34℃)下毒死蜱和噻嗪酮对褐飞虱的毒杀作用。结果表明毒死蜱在不同温度下对褐飞虱的毒力变化与噻嗪酮有所不同。处理时间相同时毒死蜱的LC50随温度升高而逐渐下降。毒死蜱处理24 h、72 h、120 h时,毒死蜱对褐飞虱的LC_(50)在22℃下分别的50.15、16.15和15.33 mg/L,而在34℃下分别降低为6.70、4.16和1.92 mg/L。在实验的5个温度下,噻嗪酮对褐飞虱的LC_(50)没有显著差异。同一温度下,噻嗪酮的LC50随处理时间的增加而降低,但没有显著差异。在全球变暖的大环境下,明确温度对毒死蜱和噻嗪酮的毒力影响状况,对于杀虫剂的合理使用具有一定的指导意义。  相似文献   

7.
研究生物量、pH、毒死蜱浓度和温度对枯草芽胞杆菌3374菌株(编号为GU086422)在水溶液中降解毒死蜱特性,考察该菌株对白菜上毒死蜱残留的降解特性。结果表明,在毒死蜱质量浓度为240 mg/L、pH7.0、温度30℃的适宜条件下,枯草芽胞杆菌3374菌株对毒死蜱的降解率达到92.48%。该菌株能够有效提高白菜叶面上毒死蜱残留的降解速度,表明其在白菜上具有有效降解毒死蜱的能力,在无公害农产品生产中具有广阔的应用潜力。  相似文献   

8.
研究了温度、水分和演替阶段及其交互作用对中亚热带丘陵红壤区森林土壤氮素矿化过程及其矿化速率的影响.结果表明:温度和演替阶段对土壤氨化速率影响显著,其中12 ℃<24℃<36 ℃,灌丛林和马尾松(Pinus massoniana)林低于常绿阔叶林(P<0.05);而水分的影响不显著.水分和演替阶段对土壤硝化速率有显著影响,土壤半饱和含水量高于自然含水量及饱和含水量,且马尾松林高于灌丛林(P<0.05);而温度的影响不显著.温度、水分和演替阶段对土壤氮净矿化速率的影响均显著,其中12 ℃<24 ℃<36 ℃,土壤半饱和含水量高于自然含水量和饱和含水量,灌丛林<马尾松林<常绿阔叶林(P<0.05).温度升高有利于提高土壤氨化速率和净矿化速率,温度过高则抑制土壤硝化速率;土壤含水量适中有利于土壤氮素矿化过程;顺行演替将提高土壤供氮能力,且抑制过强的硝化作用.  相似文献   

9.
了解植物病毒在不同水体与温度条件下的灭活规律具有重要的理论与实际意义.本文以典型植物病毒烟草花叶病毒(TMV)为模型,比较了其在不同温度条件下,在闽江水、自来水、生活污水、微孔滤膜过滤除菌污水及超纯水中的灭活动力学.结果显示,温度是导致TMV灭活的重要因素,水温升高,病毒灭活速率加快;此外,某些水质因子也影响TMV的灭活效率,其中可溶性盐的存在及其含量对TMV的灭活会因所处的环境不同而异;某些微生物或代谢产物对植物病毒TMV具有灭活作用,而能生化降解的有机质加速TMV灭活可能是通过促进水体中的微生物增殖而起作用.  相似文献   

10.
研究了温度对斜纹夜蛾核型多角体病毒病流行的影响.结果表明,温度在29 ℃以上时,感病幼虫大多在2~3 d开始死亡,4~5 d达到高峰.随着温度的升高,感病幼虫病死率增加,病死速度加快.在试验温度范围内,未发现该病毒的热抑制温度,但感病幼虫死亡速率存在恒定温区,在29~35 ℃之间.感病幼虫的每日病死率可用互补重对数模型较好地拟合,累计病死时间分布可用Gompertz模型拟合,生物物理模型经改进后可很好地描述幼虫病死速率与温度的关系,可用于模拟分析不同温度下的幼虫病死时间分布和幼虫病死速率.  相似文献   

11.
We studied the composition of products of the photochemical degradation of 3,6-dichloropicolinic acid (DCPA), the active principle of Lontrel, a herbicide broadly used in agriculture. Ultraviolet irradiation (mimicking the natural sunlight action) did not degrade DCPA completely to environmentally safe products. The rate of DCPA degradation was notably lower when distilled water was replaced by river water and even lower in sea water. Chromatomass spectrometry revealed 9 compounds among the photolysis products, in addition to undegraded DCPA.  相似文献   

12.
We studied the composition of products of the photochemical degradation of 3,6-dichloropicolinic acid (DCPA), the active principle of Lontrel, a herbicide broadly used in agriculture. Ultraviolet irradiation (mimicking the natural sunlight action) did not degrade DCPA completely to environmentally safe products. The rate of DCPA degradation was notably lower when distilled water was replaced by river water and even lower in sea water. Chromatomass spectrometry revealed 9 compounds among the photolysis products, in addition to undegraded DCPA.  相似文献   

13.
Sequential photo-and biodegradation of p-cresol was studied using a mercury lamp, as well as KrCl and XeCl excilamps. Preirradiation of p-cresol at a concentration of 10?4 M did not affect the rate of its subsequent biodegradation. An increase in the concentration of p-cresol to 10?3 M and in the duration preliminary UV irradiation inhibited subsequent biodegradation. Biodegradation of p-cresol was accompanied by the formation of a product with a fluorescence maximum at 365 nm (λex = 280 nm), and photodegradation yielded a compound fluorescing at 400 nm (λex = 330 nm). Sequential UV and biodegradation led to the appearance of bands in the fluorescence spectra that were ascribed to p-cresol and its photolysis products. It was shown that sequential use of biological and photochemical degradation results in degradation of not only the initial toxicant but also the metabolites formed during its biodegradation.  相似文献   

14.
Chlorpyrifos is a commonly used organophosphate pesticide. Its extensive use and associated serious soil and water contamination have gained increasing environmental concern. Biodegradation is a promising way to remediate chlorpyrifos contamination. There are many reports on various chlorpyrifos degrading microorganisms, but only a few on biodegradation of chlorpyrifos by consortia. Hence, the present study attempted to assemble a novel bacterial consortium C5 for the biodegradation of chlorpyrifos. The 16S rRNA gene-based molecular analysis revealed that the bacterial consortium consisted of Staphylococcus warneri CPI 2, Pseudomonas putida CPI 9 and Stenotrophomonas maltophilia CPI 15. Optimization of chlorpyrifos degradation by the consortium C5, using a Box–Behnken design, was carried out taking into account four important variables: temperature, pH, the initial concentration of chlorpyrifos and time of incubation. C5 is capable of giving 90% degradation of chlorpyrifos (125 ppm) in 8 days of incubation under optimized conditions of pH (7) and temperature (30°C). Growth curve and degradation study under optimized conditions confirmed that consortium could improve the biodegradation potential. From these results, we conclude that the novel consortium C5 of three species can be used to eliminate chlorpyrifos from various environmental compartments and can be implemented in bioreactors in a cost-effective, safe and environmentally friendly manner.  相似文献   

15.
为了研究水杨酸(SA)对高温强光胁迫下小麦叶片类囊体膜D1蛋白磷酸化和PSⅡ功能的影响,用0.5 mmol·L-1 SA溶液预处理灌浆期小麦叶片,以水预处理为对照,然后将预处理植株进行高温强光(35 ℃,1 600 μmol·m-2·s-1)处理,测定胁迫处理过程中小麦旗叶光合电子传递速率、净光合速率、叶绿素荧光参数及D1蛋白的变化.结果表明:SA预处理有效抑制了高温强光下D1蛋白的净降解,保持了较高的D1蛋白磷酸化水平、全链电子传递速率和PSⅡ电子传递速率,维持了较高的PSⅡ原初光化学效率(Fv/Fm)、实际光化学效率(ФPSⅡ)、光化学淬灭系数(qP)和净光合速率(Pn).表明外源SA通过调节小麦叶绿体D1蛋白的周转,减轻了高温强光胁迫对叶片光合机构的损伤,有利于PSⅡ的正常运转.  相似文献   

16.
Sequential photo- and biodegradation of p-cresol was studied using a mercury lamp, as well as KrCl and XeCl excilamps. Preirradiation of p-cresol at a concentration of 10(-4) M did not affect the rate of its subsequent biodegradation. An increase in the concentration of p-cresol to 10(-3) M and in the duration preliminary UV irradiation inhibited subsequent biodegradation. Biodegradation of p-cresol was accompanied by the formation of a product with a fluorescence maximum at 365 nm (lambdaex 280 nm), and photodegradation yielded a compound fluorescing at 400 nm (lambdaex 330 nm). Sequential UV and biodegradation led to the appearance of bands in the fluorescence spectra that were ascribed to p-cresol and its photolysis products. It was shown that sequential use of biological and photochemical degradation results in degradation of not only the initial toxicant but also the metabolites formed during its biodegradation.  相似文献   

17.
Photochemical treatment is increasingly being applied to remedy environmental problems. TiO2-derived catalysts are efficiently and widely used in photodegradation applications. The efficiency of various photochemical treatments, namely, the use of UV irradiation without catalyst or with TiO2/graphene-TiO2 photodegradation methods was determined by comparing the photodegadation of two main types of hydrophobic chlorinated aromatic pollutants, namely, pentachlorophenol (PCP) and polychlorinated biphenyls (PCBs). Results show that photodegradation in methanol solution under pure UV irradiation was more efficient than that with either one of the catalysts tested, contrary to previous results in which photodegradation rates were enhanced using TiO2-derived catalysts. The effects of various factors, such as UV light illumination, addition of methanol to the solution, catalyst dosage, and the pH of the reaction mixture, were examined. The degradation pathway was deduced. The photochemical treatment in methanol soil washing solution did not benefit from the use of the catalysts tested. Pure UV irradiation was sufficient for the dechlorination and degradation of the PCP and PCBs.  相似文献   

18.
用10mmol·L-1CaCl2溶液预处理灌浆期小麦叶片,以水预处理为对照,然后将预处理植株进行高温强光(35℃,1600μmol·m-2·s-1)胁迫,测定胁迫处理过程中小麦旗叶光合电子传递速率、净光合速率、叶绿素荧光参数及D1蛋白的变化,以研究外源Ca2+对高温强光胁迫下小麦叶片类囊体膜D1蛋白磷酸化和PSⅡ功能的影响.结果表明:CaCl2溶液预处理使小麦叶片在高温强光逆境下PSⅡ反应中心发生可逆失活,有效抑制了高温强光下D1蛋白的净降解,保持了较高的D1蛋白磷酸化水平,暗恢复后PSⅡ反应中心活性迅速恢复,全链电子传递速率和PSⅡ电子传递速率恢复至对照水平,维持了较高的PSⅡ原初光化学效率(Fv/Fm)、实际光化学效率(ФPSⅡ)、光化学猝灭系数(qP)和净光合速率(Pn).表明外源Ca2+通过调节小麦叶绿体D1蛋白的周转,促进了PSⅡ的正常运转,减轻了高温强光胁迫对叶片光合机构的损伤.  相似文献   

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