甲磺隆除草剂的测定方法及其吸附行为研究

采用批量平衡法系统研究了甲磺隆除草剂在几种土壤（熟化红壤、砖红壤性红壤、红筋泥、砖红壤）和矿物（高岭石、针铁矿、和Ca²⁺、Al³⁺、Cu²⁺单离子饱和蒙脱石）上的吸附行为.建立了硼酸-硼砂缓冲液体系的毛细管电泳测定甲磺隆的分析方法.甲磺隆在本实验条件下能够与土壤中的杂质达到基线分离,迁移时间为4.6 min.对比实验表明,毛细管电泳法测定甲磺隆与高效液相色谱法具有一致性.然而,毛细管电泳法能显著节省测试时间和成本,在本类吸附实验研究中具有很好的应用价值.吸附实验数据分析表明甲磺隆的吸附行为都可以用Freundlich模型描述,矿物和土壤的K_f值分别在0.82～199.69和1.97～10.48范围.在几种影响甲磺隆吸附的因素中,pH的影响作用最为显著,说明静电作用可能是甲磺隆在土壤及矿物上吸附的主要机理.     

除草剂对水稻土微生物的影响

以阿特拉津、丁草胺和甲磺隆 3种除草剂为例 ,采用熏蒸提取法和BIOLOG碳素利用法研究了土壤中除草剂污染与水稻土微生物之间的关系及其环境意义 .结果表明以 10mg·kg-1含量施入水稻土的甲磺隆在施用初期导致微生物生物量下降 ,随培养时间的推移 ,生物量有所恢复 ;相同浓度的阿特拉津和丁草胺对水稻土微生物生物量影响不明显 .BIOLOG数据显示 ,3种除草剂施用初期 (第 2d)微生物碳源利用多样性变化不明显 ,随着培养时间的增加微生物碳源利用多样性发生变化 ,变化趋势因除草剂类型不同而异 :甲磺隆除草剂污染水稻土微生物碳源利用多样性先有明显降低 ,培养后期呈上升趋势 ;阿特拉津和丁草胺除草剂污染水稻土微生物碳源利用多样性基本不受影响 .     

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 ,4 C-metsulfuron-methyl among the basic properties(soil pH, clay, OM and CEC etc. ) of soil. The maximum content of ^14C-BR in the 7 soils accounted for 19.3% -52.6% of applied amount. In addition, the composition of the ,4 C-BR in fluvio marine yellow loamy(S7) 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]-tdazine and ^14 C-metsulfuron-methyl parent compound constituted the main components of the BR derived from ^14 C-metsulfuron-methyl in the S7. 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.     

甲磺隆污染土壤的生物修复

在室内条件下,研究高效降解菌MD对甲磺隆污染环境的修复作用.结果表明,在土壤中,甲磺隆的降解顺序是:加菌鲜土>加菌灭菌土>鲜土>灭菌土,在添加MD时,1.0mg*l-1甲磺隆的降解速率明显高于10.0mg*l-1;在加菌土壤中,甲磺隆的降解遵循一级动力学方程;在土壤培养实验中,用菌处理10d的培养土壤中的生长量和不加药对照基本无差别.     

Effect of fly ash on metsulfuron-methyl sorption and leaching in soils

This investigation was undertaken to determine the effect of amendment of two fly ashes [Kota and Inderprastha (IP)] on sorption behavior of metsulfuron-methyl in three Indian soil types. Kota fly ash (5%) did not show any effect on herbicide sorption while IP fly ash significantly enhanced the sorption. Further studies on metsulfuron-methyl sorption-desorption behavior in 0.5, 1, 2, and 5% IP fly ash-amended soils suggested that effect of fly ash varied with soil type and better effect was observed in low organic carbon content soils. The sorption-desorption isotherms fitted very well to the Freundlich sorption equation and, in general, slope (1/n) values less than unity were observed. Metsulfuron-methyl sorption in the IP fly ash-amended soils showed strong correlation with the fly ash content and compared to the Freundlich sorption constant (K _f), K _FA values (sorption normalized to fly ash content) showed less variation. Metsulfuron-methyl leaching studies suggested greater retention of herbicide in the application zone in IP fly ash-amended soils, but effect varied with soil type and no herbicide leaching was observed in 5% fly ash-amended soils. The study suggested that all coal fly ashes are not effective in enhancing the sorption of metsulfuron-methyl in soils. However, one which enhanced herbicide sorption, could play an important role in reducing its leaching losses.     

甲磺隆结合残留对土壤酶活性的影响

为了研究甲磺隆结合残留对土壤酶活性的影响,将黄粉土(水稻土)经甲磺隆结合残留处理98天,检测土壤脲酶、酸性磷酸酶、过氧化氢酶和蔗糖酶活性.结果表明,甲磺隆结合残留对土壤酶活性的影响不仅与甲磺隆结合残留处理浓度和培养时间有关,同时还与土壤酶种类有关.培养前期(第14天前),甲磺隆结合残留对土壤酸性磷酸酶和过氧化氢酶具有抑制作用,而对土壤脲酶和蔗糖酶的影响则表现为低浓度时激活,高浓度时抑制;培养后期(第14天后),甲磺隆结合残留对土壤脲酶、酸性磷酸酶和过氧化氢酶具有激活作用,在一定浓度范围内(0.050~0.281mg·kg-1)对土壤蔗糖酶也具有一定激活作用;就土壤酶而言,在污染早期,土壤过氧化氢酶对甲磺隆结合残留较敏感,可以作为表征甲磺隆结合残留土壤污染的生物活性指标.