Residue and Degradation Dynamics of Bensulfuron-methyl·Mefenacet 4.2 g/kg Granule in Paddy Field

This study was conducted to determine the safety of bensulfuron-methyl and mefenacet in rice ecosystem. A field experiment was carried to reveal residual dynamics and final residue of bensulfuron-methyl.mefenacet 4.2 g/kg granule in rice and paddy system in Hangzhou, Changsha and Nanning of China during 2010 to 2011. The results showed that the average recoveries of bensulfuron-methyl and mefenacet spiked in the paddy soil, paddy water, rice, husk and rice plant at the 3 concentration levels of 0.05, 0.10 and 1.00 mg/kg ranged from 70.78% to 116.06% with the relative standard deviations of 0.91%-10.24%. The limit of detection （LOD） values of bensulfuron-methyl and mefenacet were 0.02 mg/L, and the minimum de- tection quantities were 4.0×10-9 g. The degradation dynamics test was done by spraying at a high dose （270 kg/hm2, bensulfuron-methyl active ingredient was 64.8 g/hm2, mefenacet active ingredient was 1 069.2 g/hm2） by direct spreading method 5-7 d after transplanting, and the final residual test carried out at a low dose （180 kg/hm2, bensuifuron-methyl active ingredient was 43.2 g/hm2, mefenacet active in- gredient was 712.8 g/hm2） and a high dose （270 kg/hm2）. The degradation research of bensulfuron-methyl and mefenacet in paddy water, soil and rice plant suggested that the degradation curves accorded with the first-order kinetics equation, the aver- age half life of bensulfuron-methyl was 5.35, 3.05 and 3.71 d in water, soil and rice plant, respectively, and the average half life of mefenacet was 3.61, 3.29 and 3.88 d in water, soil and rice plant, respectively. The final residues of bensulfuron-methyl and mefenacet were not detected in normal harvest paddy soil, rice straw, husk and brown rice.

Synergistic Effects of Several Additives on Herbicidal Activity of Bensulfuron-methyl

[ Objective] The aim was to select the best additives of bensulfuron-methyl. [ Method ] Taking radish as the testing plant, the synergistic effect of five common additives including Span 60, methyl olelate, silicone oil I, Tween 20 and detergent on the herbicidal activities of bensulfuron-methyl were tested in the la- borotory. [ Results ] The effects of the mixture of various additives and bensulfuran-methyl on relative stem control effect of radish, relative inhibition rate against stem length, relative inhibition rote against abeveground fresh weight, relative inhibition rote aginst root length and root fresh weight were studied, and the results showed that Span 60 and methyl olelate had stronger synergistic effect on the herbicidal activities of bensulfuron-methyl, and the synergistic effect of detergent was the weakest. [ Conclusion ] Span 60 and methyl olelate could be used as the synergistic agents of bensulfuron-methyl, and the study could provide references for se- lecting the additives of bensulfuron-methyl.

Adsorption characteristic of bensulfuron-methyl at variable added Pb^(2+) concentrations on paddy soils

The combined pollution of heavy metal Pb^2＋ and bensulfuron-methyl （BSM）, originating from chemical herbicides, in agroecological environments has become commonplace in southern China. The adsorption of BSM on three paddy soils in the presence of Pb^2＋ was examined using high-performance liquid chromatograph （HPLC）. Results indicated that adsorption of BSM could accurately be described by a Freundlich isotherm equation with correlation constant （R） 〉 0.98, irrespective of the presence of spiked Pb^2＋. Of the various factors influencing BSM sorption, soil pH appeared to be the most influential. The constant Kf of Freundlich isotherm equation tended to increase with increasing Pb^2＋ concentration in soil which indicated that the spiked of Pb^2＋ in paddy soils would promote the sorption of BSM. AGo of BSM in three paddy soils was less than 40 kJ/mol in all treatments, indicating the adsorption of BSM is mainly physical in nature. The elution of soil dissolved organic matter （DOM） enhanced the adsorption of BSM in paddy soils. The mechanisms involved in the promotion effects of the spiked Pb^2＋ on BSM adsorption might be the modified surface characteristics of paddy soil solids due to the soil acidification and the increase of soil organic matter concentration because of DOM binding.

Analysis of culturable and unculturable microbial community in bensulfuron-methyl contaminated paddy soils

To investigate the influence of bensulfuron-methyl(BSM)on culturable microbial quantities and unculturable microbial community structures,conventional and molecular biological methods were employed in five BSM treated soils with three replications,respectively. The results obtained with traditional culture-dependent methods showed that a low-level of BSM had slight and transient effects on culturable microorganisms;nevertheless,high concentration of BSM resulted in a dramatic decrease in bacterial colony fo...

Rapid degradation of bensulfuron-methyl upon repeated application in paddy soils

Rapid degradation of bensulfuron-methyl upon repeated application in paddy soils was studied. The results showed that the DT _ 50 of bensulfuron-methyl was reduced from 16 d to 9 d in soil with one-year bensulfuron-methyl application. Rapid bensulfuron-methyl degradation was happened to previously untreated soil by addition 5% rapid bensulfuron-methyl adapted soil and was inhibited following pre-treatment with broad-spectrum antibiotic chloramphenicol. In bensulfuron-methyl adapted soil mineralisation of 14 C labeled bensulfuron-methyl to 14 CO_2 occurred at a faster rate than with previously untreated soil. It was concluded that rapid bensulfuron-methyl degradation upon repeated application is probably linked to the adaptation of soil bacteria which can utilize bensulfuron-methyl as a source of carbon and energy.

Effect of Bensulfuron-Methyl on Growth of Chlorella pyrenoidosa

To study the growth effects of differing concentrations of bensulfuron-methyl on Chlorella pyrenoidosa and to evaluate the ecological risk, the effects of bensulfuron-methyl on the growth and the content change of chlorophyll and protein in Chlorella pyrenoidosa were studied through 96 h acute toxicity tests. Bensulfuron-methyl accelerated the growth of algae at lower concentrations （〈 1 mg L^-1） with content increase of chlorophyll or protein, and it inhibited the growth of algae at higher concentrations （〉 5 mg L^-1）. The content of chlorophyll or protein in algae cells reduced with the increasing concentration of bensulfuron-methyl, exhibiting the good concentration-effect relationship. The 96 h-EC50 of bensulfuronmethyl upon the algae was 15.7 mg L^-1 Bensulfuron-methyl has inhibiting effect on the growth of Chlorella pyrenoidosa and is low in toxicity.

Bound ^(14)C-metsulfuron-methyl residue in soils

Bound residue(BR) of 14 C-metsulfuron-methyl ( 14 C-BR) in seven kinds of soil was significantly negative-related to soil pH and positive-related to the clay content during the initial 20 d of incubation, but only was significantly negative-related to soil pH after 30 d incubation. Again, the soil pH was found to be the dominant factor affecting BR formation from 14 C-metsulfuron-methyl among the basic properties(soil pH, clay, OM and CEC etc.) of soil. The maximum content of 14 C-BR in the 7 soils accounted for 19.3%-52.6% of applied amount. In addition, the composition of the 14 C-BR in fluvio marine yellow loamy(S 7) at the 90 d of incubation was identified using the coupling technique of LC-MS and isotope tracing method. The results showed that the 14 C-[2-amino-4-hydroxyl-6-methyl-1, 3, 5]-triazine, 14 C-[2-amino-4-methoxy-6-methyl-1, 3, 5]-triazine and 14 C-metsulfuron-methyl parent compound constituted the main components of the BR derived from 14 C-metsulfuron-methyl in the S 7. The relative percentage of the three compounds accounted for 41.4%, 35.8% and 19.3% of total recovery radioactivity, respectively. The results also indicated that a non-radioactive component, 2-methylformate-benzenesulfonyl-isocyanate, one of the degraded products of metsulfuron-methyl in soil, was also found to be one of the components of the BR. The parent compound in BR can well explain the phytotoxic effect on substitution crops caused by the BR derived from metsulfuron-methyl in soil.

Metsulfuron-methyl Molecularly Imprinted Stir Bar Sorptive Extraction Coupled with High Performance Liquid Chromatography for Trace Sulfonylurea Herbicides Analysis in Complex Samples

Metsulfuron-methyl molecularly imprinted polymer（MIP）-coated stir bar was prepared for sorptive extraction of sulfonylurea herbicides in complex samples.The MIP-coating was about 21.3 μm thickness with the relative standard deviation（RSD） of 4.4%（n=10）.It was homogeneous and porous with good thermal stability and chemical stability.The extraction capability of the MIP-coating was 2.8 times over that of the non-imprinted polymer（NIP）-coating in hexane.The MIP-coating exhibited selective adsorption ability to the template and its analogues.The extraction conditions,including extraction solvent,desorption solvent,extraction time,desorption time and stirring speed,were optimized.A method for the determination of six sulfonylurea herbicides by MIP-coated stir bar sorptive extraction coupled with high performance liquid chromatography（HPLC） was developed.The linear range was 10―200 μg/L and the detection limits were within a range of 2.0―3.3 μg/L.It was also applied to the analysis of sulfonylurea herbicides in spiked river water,soil and rice samples.

Response of Rice Varieties to Bound Residues of Metsulfuron-Methyl in a Paddy Soil

Metsulfuron-methyl is one of the widely used sulfonylurea herbicides. However, approximately half of the applied metsulfuron-methyl may remain as bound residues in soil. To characterize the response of rice plants to residual metsulfuron-methyl in soil, the activities of acetolactate synthase （ALS）, superoxide dismutase （SOD）, peroxidase （POD）, and catalase （CAT） were investigated in two rice varieties that differed in susceptibility to the herbicide. Changes in the activity of these enzymes in leaves and roots of Xiushui 63, a sensitive rice variety, were greater than those in a resistant variety Zhenong 952. Irrespective of variety, changes in the enzyme activity were greater in the roots than in the leaves. The activities of ALS and CAT decreased, while the SOD activity increased with the increase in the amounts of bound residues of metsulfuron-methyl （BRM） in soil. The POD activity increased at the BRM level of 0.025 mg kg^-1, but decreased at the BRM level of 0.05 mg kg^-1. The results showed that the bound residues of sulfonylurea herbicides may affect metabolism of rice plants.

Research Progress in Microbiological Degradation of Bensulfuron-Methyl Herbicide

This paper reviewed the strategies and methods of screening for microorganisms having strong ability bensulfuron-methyl （BSM）, and discussed BSM degradation pathways and factors affecting its microbial metabolism prospected the research emphasis in the future to remove Finally, it

Detection of Pesticide Metsulfuron-methyl in Drinking Water by Differential Pulse Cathodic Stripping Voltammetry

Differential pulse cathodic stripping voltammetry was used to determine pesticide metsulfuron-methyl on a suspended mercury electrode.Specific experimental parameters,such as the pH of Britton-Robinson buffer,accumulation time,accumulation potential,and initial potential were optimized.The results show that a typical reduction peak appeared when pH was 2.0-4.0 and initial potential ranged from-0.75 to-1.0 V.To obtain the stripping signal of the best reduction peak,it is determined that the best pH was 2.0.The detection limit of the method was only 0.04 mg/L,and it had good selectivity and high accuracy,so the method has high sensitivity.In the analysis of actual drinking water,the recovery rate of metsulfuron-methyl could reach 93%-101%.

Effects of temperature and pH on the inhibition of Bensulfuron-Methyl(BSM)

Bensulfuron-Methyl(BSM)is a highly active sul-fonylurea herbicide that effectively controls most an-nual and perennial broadleaf or sedge weeds in paddyfield.However,the activity of BSM is affected byseveral evironmental factors.Using corn seedlings asmaterial,we found that under different temperatures

溶液pH值及模拟酸雨对两种磺酰脲类除草剂在土壤中行为的影响

采用平衡振荡法和土柱淋洗法,研究了溶液pH及模拟酸雨对土壤中苄嘧磺隆和甲磺隆行为的影响.结果表明,Freundlich方程能较好地描述苄嘧磺隆和甲磺隆的吸附等温线,水-土壤系统pH升高能明显地降低这两种除草剂在土壤中的吸附,促进其在土壤中的迁移,且吸附常数(Kf)与土壤有机质含量、粘土含量呈正相关,而与土壤pH呈负相关.pH值高的模拟酸雨对除草剂在土壤中淋溶贡献较大,且淋溶量随雨量的增大而增大.除草剂在土壤中的淋溶与土壤性质密切相关,有机质含量和粘粒含量较高的土壤对除草剂的持留能力较强.

甲磺隆和苄嘧磺隆对水华鱼腥藻生长的抑制作用研究

将广普、高效、低毒的甲磺隆、苄嘧磺隆作用于水华鱼腥藻,用分光光度法测得的藻液吸光度作为藻现存量指标,研究甲磺隆、苄嘧磺隆对水华鱼腥藻的生长效应。结果表明:甲磺隆、苄嘧磺隆对水华鱼腥藻的生长有明显的抑制作用,比传统的杀藻剂硫酸铜更优越,且其抑制作用与用药量及初始藻密度密切相关。加药越多,对水华鱼腥藻生长的抑制作用越强;藻密度越大,相应的抑制藻生长所需药量越大;加药的时间越早,抑藻效果也越好。同时以甲磺隆、苄嘧磺隆可湿性粉剂分别代替其纯品,进行了小型水体试验,抑藻效果显著,确证了磺酰脲类除草剂用于控制藻类生长、治理“水华”和“赤潮”等环境问题的可行性。

苄嘧磺隆与甲黄隆混用对稻苗安全性的联合作用

为探明苄嘧磺隆和甲黄隆复配对稻苗安全性的联合作用 ,测定了苄嘧磺隆与甲黄隆混用后一叶一心期稻苗株高的 ID5 0 值 ,ID1 0 值及其共毒系数 (CTC) .结果表明 ,试验处理中 ,仅有苄嘧磺隆 4.8× 10 - 3 g/m2 +甲黄隆19.2× 10 - 3 g/m2 等 5组混合处理的共毒系数低于 10 0 ,安全性明显提高 ;苄嘧磺隆 4.8× 10 - 3 g/m2 +甲黄隆 2 .4×10 - 3 g/m2等 2组混合处理的共毒系数接近 10 0 ,对稻苗的联合作用为相加 ;其他组合的混合处理共毒系数均大于10 0 ,对稻苗安全性下降 。

甲黄隆分别与苄嘧磺隆、醚黄隆和吡嘧磺隆混用对水稻安全性的研究

室内测定了甲黄隆单用以及分别与苄嘧磺隆、醚黄隆和吡嘧磺隆混用后对一叶一心期水稻的 IC50值和IC10值。试验结果表明：单用时对一叶一心期水稻的安全性顺序为： 苄嘧磺隆>吡嘧磺隆>醚黄隆>甲黄隆。苄嘧磺隆与甲黄隆混用液能提高对一叶一心期水稻 的安全性，吡嘧磺隆与甲黄隆混用时，吡嘧磺隆在部分浓度范围内，混用液对一叶一心期 水稻的安全性下降；醚黄隆与甲黄隆混用液对一叶一心期水稻的安全性均有降低。

除草剂甲磺隆·苄嘧磺隆与过氧化氢酶相互作用对其活性的影响

[目的]探讨除草剂甲磺隆和苄嘧磺隆和过氧化氢酶的相互作用。[方法]用油菜作为指示生物,采用高锰酸钾滴定法,通过水培试验研究除草剂甲磺隆、苄嘧磺隆和过氧化氢酶相互作用对其活性的影响。[结果]当固定除草剂浓度为2.5μg/ml,随着过氧化氢酶的浓度不断增大,油菜平均根长反而不断减小。表明过氧化氢酶的存在会促进除草剂甲磺隆、苄嘧磺隆被植物体的吸收,使甲磺隆、苄嘧磺隆与受体作用增强,对油菜类作物毒害作用增强,而且环境中过氧化氢酶的浓度越大,其危害越大。除草剂甲磺隆、苄嘧磺隆对过氧化氢酶活性没有影响,即除草剂甲磺隆、苄嘧磺隆不是过氧化氢酶的抑制剂。[结论]该研究为磺酰脲类除草剂的作用机理研究奠定了基础。

超高效液相色谱-串联质谱法测定稻田水体中的甲磺隆、苄嘧磺隆残留

建立了水体中甲磺隆、苄嘧磺隆残留检测的超高效液相色谱-串联质谱法。水样中的甲磺隆和苄嘧磺隆经C18固相萃取小柱萃取,然后用Waters Acquity UPLC BEH C18色谱柱（50 mm×2.1 mm×1.7μm）分离,以0.05%乙酸/甲醇为流动相进行梯度洗脱,流速0.4 mL/min,采用正离子电喷雾电离模式测定,外标法定量。结果表明：甲磺隆、苄嘧磺隆在1.0~500.0μg/L的浓度范围内呈良好的线性关系,相关系数分别为0.999 7和0.999 9,检出限分别为0.002 5μg/L和0.005μg/L,回收率为87.6%~98.2%,相对标准偏差小于3.5%。

坪草净在不同土壤中降解的研究

应用液相色谱法测定坪草净的有效成分甲磺隆和苄嘧磺隆在3种土壤中的残留动态。结果显示:2666.66mg·L-1的10%坪草净均匀喷雾后6h,甲磺隆在黄棕壤、黄褐土和黄潮土中的残留量分别为0.95、0.84和1.05mg·kg-1,而苄嘧磺隆在黄棕壤、黄褐土和黄潮土中的残留量分别为20.15、18.76和24.24mg·kg-1。甲磺隆、苄嘧磺隆在黄棕壤、黄褐土和黄潮土中的半衰期分别为55.5d和42.5d、88.9d和59.2d、216.6d和110.0d。试验结果表明,坪草净有效成分在黄棕壤中降解最快,而苄嘧磺隆比甲磺隆在3种土壤中更易降解。

Study on the Acute Toxicity and Genetics Toxicity of Bensulfuronk-methyl on Danio rerio

[Objective] The aim was to study the effect of bensulfuron-methyl herbicide on acute toxicity and genetics toxicity of Danio redo. [ Method] Median lethal concentration was calculated by acute toxicity test, and analyzing the herbicide whether existing in potential toxicity to aquatic organisms or not. Based on the study of acute toxicity, genetics toxicity was carried out, by calculating the micronucleus rate to judge bensulfuron-methyl herbicide whether existing in potential toxicity or not. [ Result ] The LD5o （24 h and 48 h） of bensulfuron-methyl herbicide are 0.698 ml/L and 0.637 ml/L respectively, the safe concentration was 0.159 ml/L. The results on the effects of micronucleus （MN） in erythrocytes of Danio redo induced by bensulfuron-methyl at different times and different concentrations showed that the MN rate of control group was 0.010 3%, the highest MN rate of experimental group reached to 0. 372%, it also indicated that bensulfuron-methyl herbicide had genetics toxicity to Danio redo. At the same detection time, there was dose-effect relationship of MN rate in erythrocytes between treatment and control groups with different concentrations. In the same treatment group, the MN rate in erythrocytes reached to peak value at 24 h, and decreased at 48 h and 72 h with the infection time was prolonged. [ Conclusion ] The study provides some basis for scientifically selecting and reasonably using herbicide.