本文選題：沉積物　切入點：硝化強(qiáng)度　出處：《大連交通大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：潮間帶處于海陸交錯地帶,是連接陸地和大洋生態(tài)系統(tǒng)的紐帶,其中氮素污染物和重金屬污染物是河口潮間帶地區(qū)沉積物中的主要污染物。本文以小凌河、大凌河、雙臺子河、遼河四條河流入河河口處沉積物、大凌河口附近的水稻田土、玉米旱地和蘆葦濕地和雙臺子河河口附近的玉米旱地和蘆葦濕地為研究對象,電位法測定土壤p H值,重量法測定土壤可溶鹽含量,懸浮液培養(yǎng)法測定土壤的硝化強(qiáng)度,厭氧泥漿培養(yǎng)法測定土壤的反硝化強(qiáng)度,氣體抑制法確定土壤的氮素轉(zhuǎn)化過程,原子吸收光譜測定重金屬。研究結(jié)果如下:不同沉積物及其鄰近土壤的硝化強(qiáng)度和反硝化強(qiáng)度研究顯示,四種不同河口沉積物的硝化強(qiáng)度和反硝化強(qiáng)度差異顯著,硝化強(qiáng)度表現(xiàn)為小凌河雙臺子河遼河大凌河,反硝化強(qiáng)度表現(xiàn)為遼河雙臺子河小凌河大凌河。大凌河口不同利用方式的土壤中,水稻田土、玉米旱地和蘆葦濕地的硝化強(qiáng)度均高于河流沉積物,水稻田土反硝化強(qiáng)度大于其他區(qū)域的反硝化強(qiáng)度。雙臺子河口不同利用方式的土壤中,玉米旱地的硝化強(qiáng)度最大,蘆葦濕地和玉米旱地的反硝化強(qiáng)度要大于河流沉積物,土壤p H值和可溶鹽含量與硝化和反硝化強(qiáng)度存在相關(guān)性,其中硝化強(qiáng)度與p H值呈正相關(guān),與可溶鹽含量呈負(fù)相關(guān),反硝化強(qiáng)度與p H值和可溶鹽含量均呈正相關(guān)性。對遼河沉積物氮素轉(zhuǎn)化過程研究顯示,在空氣,氧氣和氬氣存在的情況下,會有硝化作用、反硝化作用、厭氧銨氧化作用和硝態(tài)氮異化還原成銨作用的發(fā)生,空氣和好氧條件下更易于硝化作用的發(fā)生,而且沉積物的硝化作用要大于反硝化作用,同時硝化作用對底物銨氮(NH4+-N)的競爭作用要強(qiáng)于厭氧銨氧化作用,好氧條件和底物NH4+-N含量的增加有助于硝化強(qiáng)度的增強(qiáng),厭氧條件更有利于反硝化作用的發(fā)生,NH4+-N和NO3--N同時存在更有利于厭氧銨氧化作用的發(fā)生。對不同沉積物及其附近土壤的重金屬污染評價研究顯示,Cu和Zn含量均小于國家土壤環(huán)境質(zhì)量標(biāo)準(zhǔn)值(GB15618-1995)的二級標(biāo)準(zhǔn),Cr含量除了雙臺子河玉米旱地外均小于國家二級標(biāo)準(zhǔn)。用單因子污染指數(shù)法評價可以得出Cu、Zn和Cr還未達(dá)到污染水平。采用內(nèi)梅羅綜合污染指數(shù)對研究區(qū)進(jìn)行了評價,得出只有大凌河口區(qū)蘆葦濕地、雙子河口區(qū)玉米旱地和遼河口沉積物屬于輕度污染區(qū),其余地區(qū)屬于無污染區(qū)。通過潛在生態(tài)風(fēng)險指數(shù)得出單個重金屬的潛在生態(tài)風(fēng)險程度由大到小依次為CrCuZn,遼東灣采樣地區(qū)潛在生態(tài)風(fēng)險很低;地累積指數(shù)評價法得出重金屬污染程度由大到小是Cr、Zn、Cu,評價遼東灣地區(qū)采樣點的潛在生物毒性可以得出Cr金屬的潛在生物毒性很大,而Cu和Zn潛在生物毒性很小,三種金屬毒性大小依次為CrZnCu,與地累積指數(shù)評價結(jié)果相一致。
[Abstract]:The intertidal zone is located in the intertidal zone, which is the link between land and ocean ecosystem. Nitrogen pollutants and heavy metal pollutants are the main pollutants in the sediments of estuarine intertidal zone. The sediment in the estuary of four rivers of Liaohe River, paddy soil near Daling River mouth, corn dryland and Reed wetland and maize dryland and Reed wetland near Shuangtaizi River estuary were studied. The pH value of soil was measured by potentiometric method. The content of soluble salt in soil was measured by gravimetric method, nitrification intensity by suspension culture method, denitrification intensity by anaerobic mud culture method, nitrogen conversion process of soil by gas inhibition method. Determination of heavy metals by atomic absorption spectrometry. The results are as follows: the nitrification and denitrification intensity of different sediments and adjacent soils show that the nitrification intensity and denitrification intensity of four different estuarine sediments are significantly different. The nitrification intensity was shown as Daling River in Shuangtaizi River and Daling River in Shuangtaizi River in Liaohe River. The denitrification intensity of maize dryland and Reed wetland was higher than that of river sediment, and the denitrification intensity of paddy soil was higher than that of other regions. Denitrification intensity of Reed wetland and corn dry land was higher than that of river sediment. Soil pH value and soluble salt content were correlated with nitrification and denitrification intensity, and nitrification intensity was positively correlated with pH value and negatively correlated with soluble salt content. Denitrification intensity was positively correlated with pH value and soluble salt content. Studies on nitrogen conversion process in Liaohe sediment showed that nitrification and denitrification occurred in the presence of air, oxygen and argon. The anaerobic ammonium oxidation and the dissimilatory reduction of nitrate to ammonium are more likely to occur in air and aerobic conditions, and the nitrification of sediment is greater than that of denitrification. At the same time, the competitive effect of nitrification on the substrate NH _ 4-N was stronger than that on the anaerobic ammonium oxidation. The increase of aerobic conditions and substrate NH4 -N content contributed to the enhancement of nitrification intensity. Anaerobic conditions are more conducive to the occurrence of denitrification and the presence of NH _ 4-N and NO3--N at the same time. The evaluation of heavy metal pollution in different sediments and adjacent soils shows that the contents of Cu and Zn are small. The second class standard Cr content of the national soil quality standard GB15618-1995 was lower than that of the national second class standard except for the Shuangtaihe corn dry land. The results of single factor pollution index evaluation showed that Cu Zn and Cr had not reached the pollution level. The comprehensive pollution index of Nemero was used to evaluate the study area. It is concluded that only Reed wetland in Daling River estuary, corn dryland and sediment in Liaohe estuary in Shuangzi River estuary belong to light polluted area. The potential ecological risk degree of single heavy metal is CrCuZn. the potential ecological risk of sampling area in Liaodong Bay is very low by the index of potential ecological risk. The results showed that the degree of heavy metal pollution was from large to small, and the potential biotoxicity of Cr and Zn was very high, but the potential toxicity of Cu and Zn was very small, when evaluating the potential biotoxicity of sampling sites in Liaodong Bay, the results showed that the potential biotoxicity of Cr was very high, and that of Cu and Zn was very small. The toxicity of the three metals is followed by CrZnCu, which is consistent with the results of the geoaccumulation index evaluation.
【學(xué)位授予單位】：大連交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：X53;X55

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