本文關(guān)鍵詞： 外源性污染 鉛 鎘 酶 有機(jī)質(zhì)　出處：《湖南大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：隨著工業(yè)化、城市化進(jìn)程的加快,大量的工業(yè)廢水、廢渣、生活污水被排放到河流中,使得河流底泥中重金屬污染日益嚴(yán)重,并對(duì)人類的生活健康產(chǎn)生一定的危害。重金屬鉛和鎘是河流底泥中常見的兩種重金屬污染物。本文選擇河流底泥微生物酶活和有機(jī)質(zhì)降解率為研究對(duì)象,在不同濃度外源性鉛和鎘污染培養(yǎng)條件下,通過監(jiān)測(cè)底泥中脲酶活性、過氧化氫酶活性、蛋白酶活性、有機(jī)質(zhì)含量、離子態(tài)鉛含量、離子態(tài)鎘含量、EDTA態(tài)鉛含量和EDTA態(tài)鎘含量的變化,分析了底泥微生物酶活對(duì)外源性重金屬污染的響應(yīng)機(jī)制,以及外源性重金屬污染對(duì)有機(jī)質(zhì)降解率的影響。實(shí)驗(yàn)結(jié)果表明,外源性重金屬濃度和污染時(shí)間是影響生物酶活性和有機(jī)質(zhì)降解的重要因素,且這兩個(gè)因素之間的交互作用對(duì)生物酶活性有顯著的影響。實(shí)驗(yàn)初期,中低濃度的外源性鉛對(duì)脲酶有促進(jìn)作用,中高濃度的鎘對(duì)脲酶有抑制作用,受外源性鉛和鎘污染的底泥中過氧化氫酶活性和蛋白酶活性受到抑制；實(shí)驗(yàn)中期和后期,低濃度的外源性重金屬污染對(duì)底泥中脲酶、過氧化氫酶和蛋白酶有促進(jìn)作用；實(shí)驗(yàn)后期,受抑制的生物酶酶活性有所恢復(fù),但是高濃度重金屬污染條件下,生物酶活性仍受到抑制。底泥中離子態(tài)鉛和鎘的含量先上升后下降,底泥中EDTA態(tài)鉛和鎘的含量隨著時(shí)間的變化而上升。皮爾森相關(guān)分析顯示,脲酶活性變化和離子態(tài)或EDTA態(tài)鉛和鎘的含量負(fù)相關(guān)性,過氧化氫酶活性和EDTA態(tài)鉛含量之間在第3天、第10天和第30天存在極顯著的負(fù)相關(guān)性,過氧化氫酶和蛋白酶與離子態(tài)鎘和EDTA態(tài)鎘含量存在顯著的負(fù)相關(guān)性,蛋白酶活性變化和EDTA態(tài)鉛含量之間的相關(guān)性不顯著。有機(jī)質(zhì)的含量隨著時(shí)間的變化逐漸減少,受重金屬污染的底泥中有機(jī)質(zhì)含量比未受重金屬污染的底泥中含量要低,不同濃度外源性鉛和鎘污染條件下有機(jī)質(zhì)降解率存在顯著性差異,有機(jī)質(zhì)含量和外源性重金屬鉛污染下的底泥脲酶活性在第45天有顯著的正相關(guān)性,與過氧化氫酶活性在第30天有顯著地正相關(guān)性,與蛋白酶活性存在負(fù)相關(guān)性。有機(jī)質(zhì)含量和外源性重金屬鎘污染下的底泥脲酶活性在第7天、第15天和45天有顯著的正相關(guān)性,與過氧化氫酶活性在第45天有顯著地正相關(guān)性,與蛋白酶活性在第7和第30天存在顯著地正相關(guān)性。研究發(fā)現(xiàn)的結(jié)果將有利于提高對(duì)底泥生態(tài)毒理機(jī)制的認(rèn)識(shí)。
[Abstract]:With the acceleration of industrialization and urbanization, a large number of industrial wastewater, waste residue and domestic sewage are discharged into the river, which makes the heavy metal pollution in the river sediment more and more serious. Heavy metal lead and cadmium are two common heavy metal pollutants in river sediment. In this paper, microbial enzyme activity and degradation rate of organic matter in river sediment are selected as the research objects. Urease activity, catalase activity, protease activity, organic matter content, ionic lead content in sediment were monitored under different concentrations of exogenous lead and cadmium contamination. The changes of ionic cadmium content, EDTA lead content and EDTA cadmium content were analyzed. The response mechanism of microbial enzyme activity to exogenous heavy metal pollution and the effect of exogenous heavy metal pollution on the degradation rate of organic matter were analyzed. The concentration of exogenous heavy metals and the time of pollution are the important factors that affect the bioenzyme activity and the degradation of organic matter, and the interaction between these two factors has a significant effect on the bioenzyme activity. The activity of catalase and protease in the sediment contaminated by exogenous lead and cadmium was inhibited, and the activity of catalase and protease was inhibited in the middle and late stages of the experiment, and the activity of catalase was inhibited in the sediment contaminated by exogenous lead and cadmium, and the activity of catalase and protease was inhibited in the middle and late stages of the experiment. The low concentration of exogenous heavy metals can promote urease, catalase and protease in sediment, but in the late stage of experiment, the inhibited enzyme activity of biological enzyme recovered, but under the condition of high concentration of heavy metal, the enzyme activity of urease, catalase and protease in sediment was improved. The contents of ionic lead and cadmium in sediment increased first and then decreased, and the contents of lead and cadmium in EDTA increased with time. Pearson correlation analysis showed that. The changes of urease activity were negatively correlated with the contents of lead and cadmium in ionic or EDTA forms, and the activities of catalase and lead in EDTA were significantly negative correlated on the 3rd, 10th and 30th day, respectively. There was a significant negative correlation between catalase and protease and the contents of ionic cadmium and EDTA cadmium, but there was no significant correlation between the changes of protease activity and the content of lead in EDTA, but the content of organic matter decreased gradually with the change of time. The content of organic matter in sediment polluted by heavy metal was lower than that in sediment without heavy metal pollution. There was significant difference in degradation rate of organic matter under different concentrations of exogenous lead and cadmium. There was a significant positive correlation between organic matter content and urease activity in sediment contaminated by heavy metal lead on the 45th day and the catalase activity on the 30th day. The content of organic matter and urease activity of sediment contaminated by exogenous heavy metal cadmium were positively correlated on the 7th, 15th and 45th day, and positively correlated with the catalase activity on the 45th day. There was a significant positive correlation between protease activity and protease activity on the 7th and 30th days. The results of the study will help to improve the understanding of the mechanism of sediment ecotoxicology.
【學(xué)位授予單位】：湖南大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：X522;X172

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