【摘要】：汞作為全球性的環(huán)境污染物之一,它具有很高的毒性并且能夠在環(huán)境中遷移,具有較大的環(huán)境風(fēng)險且是全球污染治理的難題之一。目前,我國的汞污染也異常嚴(yán)重,因此尋求一種行之有效的治理方法至關(guān)重要。本論文針對我國汞污染的嚴(yán)峻現(xiàn)狀,希望尋找到一種富汞能力強的植物。通過對福建德化某廢棄金礦、北京石景山某鋼鐵廠和貴州萬山廢棄汞礦的采樣調(diào)查,發(fā)現(xiàn)福建德化某廢棄金礦的土壤汞濃度為117.01 mg·kg-1,北京石景山某鋼鐵廠的土壤汞濃度為2.85 mg·kg-1,而貴州萬山廢棄汞礦的土壤汞濃度為158.44～517.45 mg·kg-1,用單因子指數(shù)法評價方法得出三地均為重度污染。以植株中的汞含量、轉(zhuǎn)運系數(shù)(TF)、富集系數(shù)(BCF)、生物量等指標(biāo)作為富汞植物的篩選標(biāo)準(zhǔn),最終從貴州萬山廢棄汞礦礦區(qū)篩選出了一種大量生存、長勢良好、生物量大、汞含量高、轉(zhuǎn)運系數(shù)大、富集能力強的富汞植物—鱗毛蕨科貫眾。對篩選出來的富汞植物貫眾在人工氣候箱培養(yǎng)等實驗室模擬條件下用氯化汞染毒的土壤進(jìn)行盆栽實驗。研究表明,貫眾的耐汞濃度范圍為0～500 mg·kg-1,其中貫眾適宜的汞濃度為25～50 mg·kg-1。汞會對貫眾的生理特性產(chǎn)生一定的影響而反映出貫眾的抗脅迫能力的強弱。通過實驗發(fā)現(xiàn),貫眾體內(nèi)的超氧化物歧化酶(SOD)活性在汞濃度低時增加,汞濃度高時降低,隨著時間的延長,超氧化物歧化酶(SOD)活性開始下降；貫眾體內(nèi)的谷胱甘肽(GSH)含量隨汞濃度和時間的增加而增加；貫眾體內(nèi)的脯氨酸含量隨汞濃度的增加先減小后增加,隨著時間的延長脯氨酸的含量增加；丙二醛(MDA)含量隨汞濃度和時間的增加均呈現(xiàn)增加趨勢。貫眾仍能正常生長,表明貫眾的抗脅迫能力強。對老化和種植貫眾后的土壤進(jìn)行Tessier五步提取法形態(tài)分析,發(fā)現(xiàn)老化后土壤汞形態(tài)的大小順序為離子交換態(tài)汞碳酸鹽結(jié)合態(tài)汞有機結(jié)合態(tài)汞殘渣態(tài)汞鐵錳氧化物結(jié)合態(tài)汞,表明添加的氯化汞主要轉(zhuǎn)化為離子交換態(tài)汞和碳酸鹽結(jié)合態(tài)汞；種植貫眾后的土壤離子交換態(tài)汞和碳酸鹽結(jié)合態(tài)汞下降非常明顯,表明貫眾主要吸收離子交換態(tài)汞和碳酸鹽結(jié)合態(tài)汞。通過實驗發(fā)現(xiàn)弱酸性和少量有機質(zhì)含量條件下有利于貫眾吸收汞,堿性和過量的有機質(zhì)含量則阻礙貫眾對汞的吸收。其中,適宜的pH值范圍為6.24～6.85,適宜有機質(zhì)含量范圍為1.79%～2.81%,通過L9(34)正交實驗得出：(1)對貫眾富汞影響最大的因素為汞濃度,其次為pH值,有機質(zhì)的影響最��；(2)貫眾的最優(yōu)生長條件汞濃度為45 mg·kg-1, pH值為6.35,有機質(zhì)含量為2.52%。貫眾的富汞能力強,可以運用于工程實踐進(jìn)行檢驗。
[Abstract]:As one of the global environmental pollutants, mercury is highly toxic and can be transported in the environment. It has great environmental risks and is one of the global pollution control problems. At present, mercury pollution is very serious in China, so it is very important to seek an effective control method. In this paper, aiming at the serious situation of mercury pollution in China, we hope to find a plant with strong mercury rich ability. Based on the sampling investigation of an abandoned gold mine in Dehua, Fujian, an iron and steel plant in Shijingshan, Beijing, and an abandoned mercury mine in Wanshan, Guizhou, It was found that the mercury concentration in the soil of a abandoned gold mine in Dehua, Fujian Province, was 117.01 mg kg-1, that in a steel plant in Shijingshan, Beijing, was 2.85 mg kg-1, and that in the waste mercury mine in Wanshan, Guizhou Province, was 158.44 ~ 517.45 mg 路kg ~ (-1), respectively. A single factor index method was used to evaluate the mercury concentration in the soil. The three places are all heavily polluted. With mercury content, transport coefficient (TF), enrichment factor (BCF) and biomass in plants as screening criteria, a large amount of survival was selected from the abandoned mercury mine area in Wanshan, Guizhou Province, with good growth, large biomass and high mercury content. The mercury-rich plant, Dryopteridaceae, has large transport coefficient and strong enrichment ability. Pot experiments were carried out on selected mercury-rich plants in laboratory simulated conditions such as artificial climate chamber culture and so on. The results show that the concentration range of tolerance to mercury is 0 ~ 500 mg 路kg ~ (-1), and the suitable concentration of mercury is 25 ~ (50) mg 路kg ~ (-1). Mercury has a certain effect on the physiological characteristics and reflects the ability of resistance to stress. It was found that the activity of superoxide dismutase (SOD) increased when mercury concentration was low and decreased when mercury concentration was high. With the prolongation of time, the activity of superoxide dismutase (SOD) began to decrease. The content of glutathione (GSH) increased with the increase of mercury concentration and time, and the content of proline decreased first and then increased with the increase of mercury concentration, and the content of proline increased with the increase of time. The content of malondialdehyde (MDA) increased with the increase of mercury concentration and time. Guanzhong can still grow normally, indicating that Guanzhong has a strong ability to resist stress. Tessier five-step extraction method was used to analyze the speciation of aged and cultivated soils. It was found that the order of mercury speciation after aging was ion exchange mercury, carbonate-bound mercury, residual mercury-ferromanganese oxide mercury-bound mercury. The results showed that the added mercuric chloride was mainly converted into ion exchange mercury and carbonate bound mercury, and the soil ion exchange mercury and carbonate bound mercury decreased obviously after planting. It is shown that ion exchange mercury and carbonate bound mercury are mainly absorbed by Guanzhong. It was found that weak acidity and a small amount of organic matter were beneficial to the absorption of mercury, while alkaline and excessive organic matter content hindered the absorption of mercury. Among them, the suitable pH range is 6.24 ~ 6.85, and the suitable organic matter content range is 1.79 ~ 2.81. Through L9 (34) orthogonal experiment, it is concluded that: (1) the concentration of mercury is the most important factor, the next is pH value, and the influence of organic matter is the least; (2) the optimum growth conditions were mercury concentration of 45 mg kg -1, pH value of 6.35 and organic matter content of 2.52%. The mercury-rich ability is strong and can be tested in engineering practice.
【學(xué)位授予單位】：北京化工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：X53;X173

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