【作者】 高敏苓；

【导师】 戴树桂；

【作者基本信息】 南开大学 ， 环境科学， 2006， 博士

【摘要】 论文以取代脲类除草剂绿麦隆作为典型污染物,以三嗪类除草剂阿特拉津和硫铵、尿素作为主要影响因素,在实验室条件下研究了绿麦隆在土壤多介质环境中的复合行为。论文的主要研究内容及结论包括:(1)绿麦隆在单一及复合体系中吸附等温线的研究。吸附动力学研究发现,绿麦隆在单一和复合体系中的吸附作用均存在快吸附和慢吸附两个阶段;在灭菌处理中绿麦隆的含量高于非灭菌处理,表明在吸附过程中存在着生物降解反应。(2)阿特拉津和氮肥对绿麦隆在土壤中吸附作用影响的研究。研究发现,绿麦隆的吸附等温线均符合Freundlich等温方程。当阿特拉津与绿麦隆同时施入土壤,随着阿特拉津浓度的增加,绿麦隆吸附作用降低;当氮肥与绿麦隆同时施入土壤,土壤对绿麦隆的吸附作用增强,并随着浓度的增加而增加;而用去离子水、硫铵或尿素培养土壤6天后加入绿麦隆,其吸附作用降低。解吸实验表明,未经肥料预培养的土壤其解吸能力随氮肥浓度增加而增加;经过6天预培养后,绿麦隆从对照和氮肥处理土壤上的解吸能力无明显差别,而与未经培养的土壤相比,解吸能力增加。当绿麦隆与阿特拉津、氮肥同时存在时,其在土壤中的吸附行为不同于其在单一及二元复合体系中的吸附行为,表明当多种污染物共存时,其在环境中的行为更为复杂。(3)阿特拉津和氮肥对绿麦隆在模型吸附剂中吸附作用影响的研究。实验表明,“玻璃质”有机质对绿麦隆具有较强的吸附作用,且当多种物质共存时存在竞争吸附作用,表明绿麦隆在土壤中的吸附是分配与竞争行为同时存在的。(4)阿特拉津和氮肥对绿麦隆在不同层次土壤中降解作用的影响。实验发现,无论是在单一体系还是在复合体系中绿麦隆在深层土壤中的降解速率大于表层土壤,这表明土壤质地和有机质含量在绿麦隆的降解代谢行为中起着重要作用。当阿特拉津的浓度为0~10mg/kg时,阿特拉津对绿麦隆的降解起促进作用;当阿特拉津的浓度为10~20 mg/kg时,其对绿麦隆的降解起抑制作用,并随着浓度的增加,绿麦隆降解半衰期增加。硫铵和尿素施入土壤后,绿麦隆的降解速率降低,且绿麦隆在尿素处理土壤上的降解速率大于硫铵处理的土壤。(5)阿特拉津和氮肥对绿麦隆在土壤中淋溶行为的影响。实验结果表明,阿特拉津加入土壤后,土体中绿麦隆的残留量降低。而当阿特拉津加入含有老化的绿麦隆的土壤后,绿麦隆在土壤中的淋溶损失降低。当硫铵、尿素与绿麦隆同时施入土壤,随着氮肥浓度的增加,绿麦隆的淋溶作用降低。当硫铵、尿素加入到含有老化的绿麦隆的土壤后,土壤中绿麦隆的残留量高于未老化土壤中绿麦隆的含量。阿特拉津加入土壤后,土体中绿麦隆的残留量增加。(6)绿麦隆、阿特拉津单一及复合体系对蚯蚓急性毒性效应的研究。实验表明,绿麦隆和阿特拉津均对蚯蚓产生毒性,且阿特拉津对蚯蚓的急性毒性大于绿麦隆,而且阿特拉津和绿麦隆的复合污染对蚯蚓具有明显的协同作用,并随阿特拉津浓度的增加,协同作用增强。复合体系中中毒的蚯蚓,体内SOD酶活性高于两种农药单一体系,并随阿特拉津浓度的增加,SOD酶活性增强。通过观察HE病理切片,发现绿麦隆和阿特拉津通过不同的作用途径对蚯蚓产生毒害。绿麦隆主要破坏蚯蚓的表皮细胞和肠道,而阿特拉津则通过破损蚯蚓消化道而使其致死。(7)不同有机溶剂对绿麦隆的萃取能力存在较大差异,其大小为:甲醇>甲醇:水>乙醇>丁醇。污染土壤老化108天后, 4种有机溶剂对土壤中绿麦隆的萃取能力明显降低。其中,乙醇对绿麦隆的萃取能力下降程度最大,约为38.61%~44.97%;丁醇次之,其萃取率下降了25.45%~34.63%;而甲醇和甲醇:水对绿麦隆的萃取率下降程度大致相当。更多还原

【Abstract】 Impact of atrazine and nitrogen fertilizers on fate of chlorotoluron was studied in soil multimedia environment in this paper.The following experimental studies were conducted in this paper. (1) Research on the sorption isotherms of chlorotoluron in single and multimedia system. Adsorption of chlorotoluron followed a rapid adsorption phase in which the amount of adsorbed herbicide increased rapidly (rapid sorption), then it became slowly with the increasing of time (slow sorption). Concentration of chlorotoluron was higher in sterilized treatments than that of in insterilizered treatments. This indicated a part of chlorotoluron was degraded by microorganism during the process of adsorption. (2) Impact of atrazine and nitrogen fertilizers on the sorption of chlorotoluron in soil. The sorption of chlorotoluron was fitted by Freundlich. The sorption of chlorotoluron decreased enormously with the amount of atrazine in solution increased. The sorption of chlorotoluron increased with an increase of nitrogen fertilizers concentration as chlorotoluron and nitrogen fertilizers were applied into soil at the same time. After the soil was pre-incubated with deionized water, ammonium sulfate or urea for 6 days, chlorotoluron adsorption decreased. Chlorotoluron desorption increased with increasing of nitrogen concentration when nitrogen fertilizers and chlorotoluron were applied into soil at the same time. Furthermore, desorption of chlorotoluron was of no significant difference from 6-day incubation with nitrogen fertilizers compared to control. Desorption capability of chlorotoluron in incubated soils was greater than that of in un-incubated soil. The sorption of chlorotoluron in tri-solution was different from in single and bi-solution, which indicated the environmental behaviors of pollutants were more complicated in multi-media system. (3) Impact of atrazine on the sorption of chlorotoluron in model sorbents. The results suggested the sorption of chlorotoluron was stronger on“glass”organic matter than that of in cellulose and silica, indicating the sorption of chlorotoluron included distribution and competition in soil. (4) Impact of atrazine and nitrogen fertilizers on the degradation of chlorotoluron in different depth. The results showed the degradation rate of chlorotoluron increased with an increase of soil depths in single and mixture systems, indicating texture and organic matter of soil that were important on the degradation progress of chlorotoulron in soil. The degradation of chlorotoluron was accelerated when concentration of atrazine was 0~10mg/kg. However, degradation of chlorotoluron decreased when concentration of atrazine was 10~20mg/kg and half-life increased with increasing of atrazine concentration. After ammonium sulfate and urea were applied into soil, the degradation rate of chlorotoluron from these soils was slower than that of in untreated the soils with fertilizers. Moreover, degradation rate of chlorotoluron was faster in urea-treated soils than ammonium sulfate-treated soils in different soil depth. (5) Effect of atrazine and nitrogen fertilizers on the leaching of chlorotoluron in soil. The mobility of chlorotoluron increased when chlorotoluron and atrazine were applied into soil at the same time. However, the amount of chlorotoluron increased in soil column after the atrazine was applied into soil including aged chlorotoluron. Ammonium sulfate and urea reduced chlorotoluron leaching losses of chlorotoluron when fertilizers and chlorotoluron were applied into soil. More chlorotoluron remained in the soil columns were observed in urea treatments than in ammonium sulfate treatments. On the other hand, more chlorotoluron remained in the aged soil columns than that of in non-aged soil columns. (6) Toxicity of single and binary herbicide system combined with chlorotoluron and atrazine to earthworm Eisenia foetida was investigated. The results showed atrazine and chlorotoluron were toxic to earthworm, and that atrazine was more toxic to earthworm than chlorotoluron, the synergistic toxic effect of combined herbicides system to the earthworm. SOD activity of earthworms was greater in combined system than in single system, and that increased with an increase of atrazine concentration. The pathological section showed that the herbicides executed their effects on different parts. After chlorotoluron entering into earthworms, epidermis and intestines of earthworms were ruined. While atrazine ruined alimentary tract of earthworms and resulted death of earthworms. (7) The extractability of organic solvents was significantly different, with extractability decreasing in the order: methanol > methanol: water > ethanol > butanol. The extraction capacity of organic solvents was decreased for chlorotoluron after ageing 108 days. The extractability of ethanol was decreased by 38.61%~44.97% more than that of others; the extraction capacity of butanol was decreased by 25.45%~34.63%; it was same to methanol and methanol: water.更多还原