【作者】 姚斌；

【导师】 徐建明；

【作者基本信息】 浙江大学 ， 土壤化学与环境， 2003， 博士

【摘要】 农药的大量使用，使得我国不少地区的土壤受到了一定程度的污染，并且具有量大、面广和分散的特点。阿特拉津、丁草胺和甲磺隆是目前我国广泛使用的三大类除草剂，有关研究者已对该三类除草剂在土壤中的物理、化学和生物学行为进行了深入的研究，但有关在一定控制条件下该3大类除草剂的降解特征及其对土壤中微生物学指标的影响研究相对缺乏。本文以中性的丁草胺、弱碱性的莠去津和弱酸性的甲磺隆三种不同性质的常用除草剂为研究对象，研究了一定控制条件下，除草剂在土壤中的降解动态规律及其相关的生物学指标对除草剂污染的响应，试图通过表征土壤质量的生物学指标来揭示污染土壤修复过程中环境友好演变的过程和机理，为采用调节环境条件、依靠土壤自然微生物活性的提高而快速原位修复污染土壤的技术提供理论依据。取得的主要研究结果如下： 1．控制条件下阿特拉津在土壤中的降解研究 不同温度和不同含水量控制条件下，研究了除草剂阿特拉津在黄筋泥田、青紫泥田和淡涂泥田三种土壤中的消长动态规律。研究结果表明： （1）当土壤含水量为40％田间最大持水量时，在不同温度（15℃、25℃、35℃）恒温培养条件下，土壤中阿特拉津残留总量随时间的变化均满足一级反应动力学方程C=Coe^-kt。随温度的提高，土壤中阿特拉津的降解速度加快，降解半衰期缩短。15℃、25℃和35℃阿特拉津在黄筋泥田、青紫泥田和淡涂泥田中的降解半衰期分别为31.2～59.2d、15.0～25.6d和10.5～32.7d。从试验结果看，较高温度土壤环境中间特拉津残留物的降解速率要比低温环境中快。 （2）35℃恒温培养条件下，土壤含水量从40％田间最大持水量增加到60％田间最大持水量，提高了阿特拉津除草剂在土壤中的降解速率。在生产实践中可以通过调节土壤温度和土壤水分条件来提高土壤微生物的活性及促进除草剂的降解。 2．控制条件下丁草胺在土壤中的降解研究 不同温度和不同含水量控制条件下，研究了除草剂丁草胺在黄筋泥田、青紫泥田和淡涂泥田三土壤中的消长动态规律。研究结果表明： （1）温度对丁草胺在土壤中的降解影响明显，相同土壤含水量（40％田间最大持水量）三个温度（15C、25’C、35C）恒温培养条件下，丁草胺除草剂的消长动态规律表现为：温度越高，土壤中丁草胺降解越快，降解半衰期缩短；15’C、25C和35’C温度条件一卜厂草胺在黄筋泥田、青紫泥田和淡涂泥田中的降解半衰期分别为13．l～105d、11．7～21．Zd和10．5～26d：土壤中丁草胺残留总量随时间的变化满足一级反应动力学方程C＝C；；e－‘’。从试验结果看，较高温度土壤环境中丁草胺残留物的降解速率要比低温环境中快。 （2）土壤含水量对丁草胺在土壤中的降解具有明显影响，测定结果显示35C恒温培养条件下，随土壤含水量的增加，丁草胺在土壤中的降解速度加快。40％田间最大持水量条件下了草胺在黄筋泥田、青紫泥田和淡涂泥田中的DI。分别为：16．Zd、m．sd、32．7d；60％田间最大持水量条件下了草胺在相应三种土壤中的DT；。。分别为：15．id、9．gd、13．sd。3．除草剂污染对土壤环境质量生物学指标的影响 阿特拉津、丁草胺和甲磺隆三种除草剂以10mg．kg－’浓度施入土壤后对土壤环境生物学指标有一定程度的影响，测定结果表明，除草剂对土壤环境生物学指标的影响效应是随时间变化的。 ＊)土壤受除草剂污染后土壤微生物生物量碳明显降低，尤其是在培养初期，除草剂对士壤微生物生物量的影响较大。当除草剂在土壤中被降解后，其对生物量碳的影响随之降低。相同除草剂在不同土壤中对土壤微生物生物量碳的影响程度是不同的。阿特拉津除草剂对供试土壤微生物生物量碳的影响顺序为：淡涂泥田＞青紫泥田＞黄筋泥田；丁草胺为：淡涂泥田＞黄筋泥田＞青紫泥田；甲磺隆为：青紫泥田＞淡涂泥田＞黄筋泥田。同一土壤，不同除草剂对微生物生物量碳的影响亦不相同，黄筋泥田中除草剂对土壤微生物生物量碳的影响顺序为：甲磺隆＞丁草胺＞阿特拉津；青紫泥田为：甲磺隆＞阿特拉津＞丁草胺；淡涂泥田为：丁草胺＞甲磷隆＞阿特拉津； （2）土壤受除草剂污染后土壤微生物生物量氮明显降低，尤其是在培养初期，除草剂对土壤微生物生物量氮的影响较大。当除草剂在土壤中被降解后，其对生物量氮的影响随之降低。相同除草剂在不同土壤中对土壤微生物生物量氮的影响程度是不同的。阿特拉洋对供试土壤微生物生物量氮的影响顺序为：青紫泥田＞淡涂泥田＞黄筋泥田：丁草胺为：淡涂泥田＞青紫泥田＞黄筋泥田；甲磷隆为：淡涂泥田＞青紫泥田＞黄筋泥田。研究表明，不同除草剂施入同一土壤对微生物生物量碳的影响亦不相同，阿特拉津、丁草胺和甲磷隆三种除草剂施入黄筋泥田对土壤微生物生物量碳的影响顺序为：甲磺隆＞丁草胺＞阿特拉津。三种供试除草剂施入青紫泥田对土壤微生物生物量氮的影响顺序为：甲磺隆＞丁草胺＞阿特拉津。三 n种供试除草剂施入淡涂泥田对土壤微生物生物?更多还原

【Abstract】 The soils in some areas of China were contaminated by herbicide application, with thecharacteristic of big mass, lager scope and scattered. Atrazine, butachlor and metsulfuron-methyl are three kinds of herbicides that have been mostly used in China. The physico-chemical and biological behavior of these three herbicides have been evaluated by many researchers, but the studies related to the herbicide decomposition and their influence on soil microbiological indicators are very little. Atrazine, butachlor and metsulfuron-methyl herbicides were chosen to evaluate their dynamic characters of decomposition in contaminated soil, and the response of biological indicators to explain the process and mechanism of their relationship for remediation of contaminated soils. The main results are summarized as follows:1. Degradation of atrazine under controlled environmental conditions(1) The changes of total amount of atrazine’s residue with time satisfied kinetics formula C=C0e-kt, when the soil water holding capacity (WHC) is 40% and incubation constant temperatures are 15℃,25℃ and 35℃, respectively. In this experiment the rate of degradation for atrazine increased and half-life decreased with increase in temperature. The half-life of atrazine was 15.2 days to 59.2 days, 15.0 days to 25.6 days and 10.5 days to 32.7 days under 15℃,25℃ and 35 ℃ temperature, respectively. This indicated that the residues of atrazine degraded faster at high temperature than at low temperature.(2) Incubation at 25 "C, the degradation rate of atrazine increased with increasing WHC from 40% to 60%. It means that he activity of microbes and also the degradation of herbicide were improved by regulating soil water content and soil temperature.2. Degradation of butachlor under controlled environmental conditions(l)During the incubation time the degradation rate of butachlor at 40% of water holding capacity (WHC) increased with increased in incubation temperature from 15℃ to 35℃. It was found that there was a steady loss of butachlor in soils with time and can be explained by thefirst-order equation. But the range of half-life for butachlor was different under different temperatures. The half-life of butachlor under 15"C, 25癈 and 35’C were 15.2 day .to 59.2 day, 15.0 day to 25.6 day and 10.5 day to 32.7 day, respectively. It was found that the residues of butachlor degraded faster at high temperature than at low temperature. The microbial bioactivity and soil properties can influence the degradation rate of butachlor(2) The degradation rate of butachlor under 35 癈 incubation increased with increase of the WHC from 40% to 60%. The half-life of butachlor were 16.2d, 10.5d and 32.7d when WHC was 40% ,and IS.lday, 9.9day and 13.5day when WHC was 60% in different type of soil ( paddy field on Quaternary red soil, blue clayed paddy soil and paddy field on desalting muddy polder).3. Influence of herbicides contamination on soil microbial indicatorsThe results indicated that the microbial indicators was significantly affected by three herbicides application to soil at the rate of lOmg kg"1. The soil microbial biomass was largely influenced by herbicide and this influence decreased with the time.(1) The soil microbial biomass C content decreased apparently at starting stages. Different herbicides showed different degree of influence on soil microbial biomass C. The order of influence on microbial biomass C in different soils by atrazine application was: paddy field on desalting muddy polder>blue clayed paddy soil>paddy field on Quaternary red soil. The sequence of influence on microbial biomass C in different soils by butachlor application was: paddy field on desalting muddy polder>paddy field on Quaternary red soil>blue clayey paddy soil. For this the order of influence of metsulfuron-methyl application microbial biomass C in different soils was: blue clayed paddy soil>paddy field on desalting muddy polder>paddy field on Quaternary red soil. The three herbicides’ influenced the soil microbial biomass C i更多还原