大豆田土壤中氯嘧磺隆残留动态研究

采用高效液相色谱法对大豆田土壤中的氯嘧磺隆残留动态进行了研究。结果表明,氯嘧磺隆在大豆田土壤中的降解半衰期为7～10d,施药后60d其残留量为0．004mg／kg。     

氯嘧磺隆高效降解细菌的分离与筛选

从北京市、河北省一些农田和农药厂排污口活性污泥中分离得到7株具有明显降解氯嘧磺隆作用的降解细菌,这些菌株能够以氯嘧磺隆为唯一氮源生长,对氯嘧磺隆的降解率为65．85％至94．78％不等。其中F-1和E-1两株菌为本试验的最高效率的降解菌,在40ml培养基、细菌起始浓度7.6×10^7cfu／ml、30℃恒温、180r／min条件下培养72h,F-1菌株对底物氯嘧磺隆50mg／L的降解效率为67．5％;E-1菌株对底物氯嘧磺隆10mg／L的降解率为94．78％。     

降解菌2N3对被氯嘧磺隆污染土壤的生物修复

在实验室条件下,研究了高效降解菌2N3(克雷伯氏菌属,Klebsiella sp.)对被氯嘧磺隆污染土壤的修复作用及其影响因素。当土壤中氯嘧磺隆的添加浓度为20 mg/kg,每 1克土壤中2N3的接菌量为1×106个菌体时,第30 d时土壤中氯嘧磺隆的降解率为84.6%,对照仅为13.4%;相同2N3接菌浓度下,当土壤中氯嘧磺隆浓度为100 mg/kg时,其降解率为31.1%。以小麦、玉米、黄瓜为供试作物,在土壤中施加 20 mg/kg的氯嘧磺隆, 当每 1克土壤中2N3的接菌量为1×106个 菌体时,小麦、玉米、黄瓜的出苗率分别为85%,82%和79%,且处理组株高高于对照,表明降解菌2N3具有明显减轻氯嘧磺隆药害的作用。研究表明,人工接种降解菌2N3可提高土壤中氯嘧磺隆的降解率,有效降低其在土壤中的残留。     

单嘧磺隆在土壤中的残留分析和消解动态研究

研究了新磺酰脲除草剂单嘧磺隆在土壤中的残留分析方法及其土壤消解动态和最终残留。土壤经甲醇和稀氨水混合液提取 ,液液分配及 C18净化 ,浓缩后用带紫外检测器的高效液相色谱仪进行测定。单嘧磺隆的最低检出量为 4 ng,在土壤中的最低检出浓度为0 .0 2 mg/ kg。本方法的添加回收率为 95.10 %～ 10 3.77% ,变异系数为 1.4 7%～ 11.80 % ,符合农药残留分析的要求。运用上述方法 ,测定了单嘧磺隆在北京和山东土壤中的消解动态以及最终残留。结果表明 :单嘧磺隆在土壤中消解的速度较慢 ,在北京土壤中的半衰期为 9.2 4 d,山东土壤中的半衰期为 13.59d。按推荐剂量施药 ,小麦收获时 ,在北京和山东两地土壤中均未检出单嘧磺隆。     

氯嘧磺隆抗体制备的研究

以合成的半抗原与牛血清白蛋白(BSA)的联结物为免疫抗原,获得对氯嘧磺隆高亲合力的兔抗血清,建立了氯嘧磺隆的直接竞争酶联免疫检测方法。抗血清效价为6.4×104,IC50值为10.9 ng/mL,测定的线性范围是0.4 ~295.4 ng/mL。在河水中的添加回收率为87.9% ~115.7%。结构相似的常用磺酰脲类除草剂与氯嘧磺隆抗体的交叉反应率为0.1% ~4.8%。所建立的方法可用于河水中氯嘧磺隆的残留检测。     

巨大芽胞杆菌E-1菌株对土壤氯嘧磺隆残留的降解效果

采用玉米对氯嘧磺隆敏感的原理,测定巨大芽胞杆菌E-1对土壤氯嘧磺隆残留的降解能力。结果表明降解菌用量为300 mL菌液/kg土时,对玉米根长的修复率为18.31%～62.48%;降解菌用量30 mL菌液/kg土时的修复率为11.78%～49.72%;降解菌用量3 mL菌液/kg土时,施用降解菌的处理与不施菌处理之间无显著差异。     

氯吡嘧磺隆高效液相色谱分析方法研究

本文采用液相色谱法,以乙腈和水为流动相,使用Promosil-C185μm填料的不锈钢柱和紫外检测器,在260nm波长下对氯吡嘧磺隆原药进行分离和定量分析。结果表明氯吡嘧磺隆的线性相关系数为0.999 8;标准偏差为0.23;变异系数为0.24%;平均回收率为99.93%。     

氯嘧磺隆高效降解菌株黑曲霉（TR-H）最佳降解条件的研究

试验采用高效液相色谱法测定不同条件下反应液中氯嘧磺隆除草剂的降解率,确定氯嘧磺隆高效降解菌株黑曲霉(TR-H)的最佳降解条件。结果表明:当氯嘧磺隆的初始浓度为10.0mg/L、接种量为5.0mL菌悬母液、反应液的温度为30.0℃、恒温振荡培养7d,真菌黑曲霉(TR-H)可以降解96.4%以上的氯嘧磺隆。     

高效液相色谱-串联质谱检测水稻中氯吡嘧磺隆残留量

建立了高效液相色谱-串联质谱检测糙米、稻壳和秸秆中氯吡嘧磺隆残留的分析方法。样品经乙腈和水提取,C 18吸附剂净化,多反应监测模式检测,外标法定量。结果表明,在0.01~2mg/L范围内,氯吡嘧磺隆的质量浓度与对应的峰面积间呈良好的线性关系,其相关系数为0.9997。在0.01~0.5mg/kg添加水平下,氯吡嘧磺隆在糙米中的平均回收率为95%~98%,相对标准偏差(RSD)为2%~4%。在0.05~5mg/kg添加水平下,氯吡嘧磺隆在稻壳和秸秆中的平均回收率为78%~87%,相对标准偏差(RSD)为1%~5%。氯吡嘧磺隆在糙米中的定量限(LOQ)为0.01mg/kg,在稻壳和秸秆中的定量限(LOQ)为0.05mg/kg。该方法简便、快速、准确。     

安全剂R-28725保护玉米免受氯嘧磺隆药害的机理研究

研究了安全剂R-28725对玉米的保护作用及对氯嘧磺隆的解毒机理。当氯嘧磺隆的使用量为5、10、15 g/hm2时,加入R-28725能够明显提高玉米株高、株鲜重和产量,直接增加玉米体内谷胱甘肽(GSH)含量,增加氯嘧磺隆与谷胱甘肽的轭合,从而达到解毒的目的。     

Studies on photodegradation of chlorimuron-ethyl in soil

Photolysis of chlorimuron-ethyl was studied on a soil surface under sunlight and UV light. Eight photoproducts were isolated and characterised by spectroscopic methods. Major photoproducts are formed by cleavage of the sulfonylurea bridge and minor products are formed via dechlorination, hydrolysis and cyclisation. The rates of photodegradation of chlorimuron-ethyl on different soils followed first-order rate kinetics, with half lives of 22·3 h, 9·4 h, 4·9 h (UV) and 20·7 days, 11·1 days and 11·1 days (sunlight) for alluvial, red and laterite soils, respectively. The differences in rates of photodegradation were dependent upon the soil pH. © 1997 SCI     

Studies on the degradation of bis(tributyltin) oxide in soil

The degradation of bis(tri[1-¹⁴C]butyltin) oxide in two soils (1 mg tin kg^?1) has been studied under laboratory conditions. Half of the applied compound disappeared from unsterilised silt loam and sandy loam in approximately 15 and 20 weeks, respectively; it disappeared also from the sterilised soils but to a lesser extent. The formation of small amounts of dibutyltin derivatives was established by thin-layer chromatography both in the unsterilised and sterile soils. The amount of unextractable radioactivity increased with time in the unsterilised and sterile soils. In the unsterilised soils ¹⁴C was released as [¹⁴C]carbon dioxide in amounts equivalent to 20% of the applied radioactivity for silt loam and 10.7% for sandy loam over a period of 42 weeks. Almost no [¹⁴C]carbon dioxide was released from the sterile soils, confirming microbial participation in the degradation of the compound in the unsterilised soils.     

The degradation of methazole in soil. II. Studies with methazole,methazole degradation products and diuron

[¹⁴C]-Labelled methazole, 1-(3,4-dichlorophenyl)-3-methylurea (DCPMU), 1-(3,4-dichlorophenyl)urea (DCPU), and diuron were incubated in soil at 20°C and field capacity soil moisture content. Decomposition followed first-order kinetics; half-lives for degradation of these four compounds were 2.4, 144, 30 and 108 days respectively. The amount of DCPMU and DCPU that could be extracted decreased with time and the decrease was accompanied by the generation of an equivalent amount of ¹⁴CO₂. This was not so in the studies with diuron and methazole, however, and the decrease in the concentrations of radioactivity extracted from soil treated with these compounds could not be entirely accounted for as carbon dioxide. It is concluded that the unextractable radiochemical that was present was DCPMU. Methazole appeared to be degraded through DCPMU to 3,4-dichloroaniline (DCA) with the production of only traces of DCPU.     

Effect of soil storage on propanil degradation

Sassafras sandy loam soil was subjected to various storage conditions after collection and 3′,4′-dichloropropionanilide (propanil) was used for testing the biodegradation potential of the stored soil. Cleavage of propanil was affected drastically after 5 days’ moist storage at 0, 10, 25 or –15° C and by 5 days’ air-drying. In 1 week approximately 90% of the propanil was degraded when fresh soil samples were used. However, 60–80% of residual propanil was found in soil which had been stored under various conditions from 5 to 30 days. Samples air-dried for 10 days were mildly affected as compared with the samples moist-stored at various temperatures, indicating that restricted gas exchange had a detrimental effect on biodegradation in moist-stored samples. These findings show that any biodegradation study should be conducted with fresh soil samples. Effet de la conservation du sol sur la degradation du propanil Un sol argilo sableux a été soumis apres prélèvement à diverses conditions de conservation et du 3,4-dichloropro-pionanilide (propanil) a été utilisé pour estimer le potentiel de biodégradation du sol ainsi conservé. La dégradation du propanil aété profondément affectée aprés 5 jours de conservation à l'humidité, à 0, 10, 25 ou –15° C et par 5 jours de séchage à l'air. En une semaine, 90 % environ du propanil aété dégrade dans le cas oil des échantillons frais de sol ontété utilises. Toutefois, 60 a 80 % de propanil résiduel aété retrouvé dans un sol conservé pendant 5 à 30 jours dans des conditions variées. Les eéchantillons séchés k l'air pendant 10 jours ontété moyennement affectés en compar-aison avec les échantillons conserves ä l'humiditéä des températures variées; ceci indique que la restriction des échanges gazeux a un effet défavorable sur la biodégradation dans les échantillons conserves à rhumidité. Ces résultats montrent que toute étude de biodégradation devrait être conduite avec des échantillons de sol frais. Wirkung der Lagerung von Boden auf den Abbau von Propanil Boden (Sassafras-sandiger-Lehm) wurde nach der Probennahme unter verschiedenen Bedingungen gelagert und, seine biologische Abbaufahigkeit mit 3′,4′-Dichlorpro-pionanilid (Propanil) untersucht. Der Abbau von Propanil wurde nach fünftägiger Lagerung des Bodens in feuchtem Zustand bei 0, 10, 25 oder – 25°C und fünftägiger Lufttrocknung sehr stark beeinflusst. Wenn frische Bodenproben verwendet wurden, waren nach einer Woche etwa 90% des Herbizids abgebaut. Dagegen waren noch 60–80% des Propanils vorhanden, wenn der Boden unter verschiedenen Bedingungen 5–30 Tage gelagert worden war. Proben die 10 Tage lang luftgetrocknet wurden, waren, verglichen mit den bei verschiedenen Temperaturen feucht gelagerten Bodenproben, nur wenig beeinflusst. Das weist darauf hin, da ein verringerter Gasaustausch sich schädlich auf die im feuchten Zustand gelagerten Proben auswirkte. Diese Ergebnisse zeigen, dass jede Untersuchung des biologischen Abbaus von Herbiziden im Boden mit frischen Bodenproben durchgefuhrt werden sollte.     

环酰菌胺在土壤中的吸附及降解特性

为评价环酰菌胺在土壤中的生态风险,采用超高效液相色谱-串联质谱(UPLC-MS/MS)方法测定了土壤和水中环酰菌胺的残留量,研究了该农药在红壤和水稻土中的吸附及降解特性,并对其淋溶特性进行了分析,评估了该农药对地下水的污染风险。结果表明:环酰菌胺在红壤和水稻土中的吸附符合Freundlich吸附等温线方程,KOC值分别为373.69和726.86 mL/g,水稻土对环酰菌胺的吸附能力强于红壤。好氧条件下,环酰菌胺在红壤和水稻土中的降解半衰期分别为0.63和5.06 d,积水厌氧条件下的降解半衰期分别为6.80和9.24 d,表明环酰菌胺在好氧条件下降解较快。环酰菌胺在红壤和水稻土中的地下水污染指数(groundwater ubiquity score)分别为1.19和1.10,表明其对地下水的污染风险较低。结果可为环酰菌胺的生态风险评估提供参考。     

The soil degradation of the herbicide florasulam

The route and rate of degradation of florasulam, a low‐rate triazolopyrimidine sulfonanilide herbicide, was investigated in six soil types under aerobic conditions at 20 or 25 °C. Degradation products were isolated and identified by mass spectroscopy. Florasulam was rapidly degraded by microbial action with an average half‐life of 2.4 days (range 0.7 to 4.5 days). The first step in the degradation pathway involved conversion of the methoxy group on the triazolopyrimidine ring to a hydroxy group to form N‐(2,6‐difluorophenyl)‐8‐fluoro‐5‐hydroxy[1,2,4]triazolo[1,5‐c]pyrimidine‐2‐sulfonamide. This metabolite degraded, with a half‐life of 10 to 61 days, via partial breakdown of the triazolopyrimidine ring to form N‐(2,6‐difluorophenyl)‐5‐aminosulfonyl‐1H‐1,2,4‐triazole‐3‐carboxylic acid. This was followed by cleavage of the sulfonamide bridge to form 5‐(aminosulfonyl)‐1H‐1,2,4‐triazole‐3‐carboxylic acid. Other degradation processes involved decarboxylation of the carboxylic acid metabolites and mineralisation to form carbon dioxide and non‐extractable residues. © 2000 Society of Chemical Industry     

呼伦贝尔草甸草原羊草群落不同退化程度土壤理化指标

文中对放牧干扰下不同退化程度呼伦贝尔草甸草原羊草群落土壤理化性质进行了研究。结果发现,土壤含水量、土壤全氮、土壤有机物、土壤速效氮随着退化程度的增加显著下降,而土壤容重、土壤(1-2mm)粗粒百分含量、土壤速效钾随着退化程度的增加而显著提高。土壤速效磷和pH值没有规律性变化。通过研究表明:土壤含水量、土壤容重、土壤(1-2mm)粒径粗粒、土壤有机物、全氮、速效氮和速效钾在不同退化程度之间都具有显著性差异,因此,这些指标可做为草甸草原羊草群落确定土壤退化程度的退化指标。     

Further observations on the enhanced degradation of iprodione and vinclozolin in soil

The effects of soil pH on rates of degradation of iprodione and vinclozolin were measured in a silty clay loam soil. Little degradation of either fungicide occurred at pH 4.3 or 5.0, and degradation at pH 5.7 was slower than at pH 6.5. In both of the higher-pH soils, the rate of loss of a second application of either fungicide was faster than that of the first, and a third application degraded even more quickly. In soil with pH 6.5, for example, the times for 50% degradation of iprodione following the first, second and third applications were about 30, 12 and 4 days, and for vinclozolin were 30, 22 and 7 days respectively. Iprodione degraded very rapidly in a sandy loam that had been treated three times previously with this fungicide and also degraded rapidly in the same soil pretreated three times with vinclozolin. Vinclozolin degraded rapidly in the vinclozolin pre-treated soil, but its rate of loss in the iprodione pre-treated soil was only slightly faster than in the previously untreated control. Studies of iprodione degradation in 33 soils from commercial fields demonstrated a clear trend towards faster rates of loss in soils with an extensive history of iprodione use. The time for 90% loss from previously untreated soils varied from 22 to 93 days. It varied from 16 to 28 days in soils treated once previously and from 5.2 to 23 days in soils treated twice previously. In soils that had received three or more previous doses, the time to 90% degradation varied from 3.8 to 15 days.