本文選題：多環(huán)芳烴 + 巖溶水系統(tǒng)��； 參考：《中國地質(zhì)大學》2014年博士論文

【摘要】：多環(huán)芳烴(PAHs)是一類具有致癌性、致突變性、難降解的典型持久性有機污染物,由兩個或兩個以上的苯環(huán)結構組成,主要來源于化石燃料和生物質(zhì)的不完全燃燒。多環(huán)芳烴對人體的中樞神經(jīng)和血液的破壞作用很強,尤其是帶烷基側鏈的PAHs,對人體粘膜的刺激性及麻醉性極強。多環(huán)芳烴可以通過各種環(huán)境介質(zhì)(大氣、土壤、懸浮顆粒、水體、生物體等)長距離遷移,并能長期存在于生態(tài)環(huán)境中,對生態(tài)環(huán)境、動植物和人體健康造成嚴重的危害。 世界上約有25%的人口以巖溶水作為主要的飲用水源。我國碳酸巖分布面積約占全國陸地面積的14%,全國約有四分之一的地下水資源分布在巖溶地區(qū)。近年來,水體污染正加劇我國的地下水水質(zhì)危機。 山西省郭莊泉域缺失了上奧陶統(tǒng)、志留系、泥盆系和下石炭統(tǒng)的地層,石炭系地層就直接沉積在中奧陶統(tǒng)地層之上,下部煤層和灰?guī)r含水層間僅只有本溪組地層。在山西本溪組地層厚度一般為30多米,南部地區(qū)較薄,一般為20米左右,呈現(xiàn)出一種“水煤共生”的地層分布格局。這樣在與灰?guī)r含水層相隔很近的地層中開采煤炭,勢必會對巖溶水環(huán)境產(chǎn)生影響。 巖溶水易受人類活動的影響。深入研究巖溶地下水系統(tǒng)中持久性有機污染物的來源、組成、遷移轉(zhuǎn)化特征,以及人類活動對巖溶地下水污染的影響都是非常必要的。本文以山西省郭莊泉巖溶地下水系統(tǒng)為例,對地表水滲漏過程中多環(huán)芳烴的光降解、含水層介質(zhì)的吸附、地下水環(huán)境中微生物的降解作用進行研究,闡明多環(huán)芳烴在環(huán)境介質(zhì)中的分布、歸趨及影響因素,為巖溶水資源的保護提供科學依據(jù)和技術支撐。 論文的主要研究內(nèi)容可以分為以下幾個方面：1.多環(huán)芳烴的分布與來源 本文研究了郭莊泉巖溶水系統(tǒng)中多環(huán)芳烴在表層土、地下水、懸浮物中的濃度、空間分布規(guī)律和污染來源�？偠喹h(huán)芳烴在表層土中的濃度范圍為622-87882ng/g,懸浮物中的濃度范圍為4739-59315ng/g,地下水中的濃度范圍為2137-9037ng/L,各環(huán)境介質(zhì)中的平均濃度分別為17174ng/g,11992ng/g及5020ng/L。根據(jù)以上數(shù)據(jù),研究區(qū)被認定為已經(jīng)遭受中度甚至重度污染。補給區(qū)R1的多環(huán)芳烴主要來源于煤系地層中原煤的淋濾與解吸；汾河滲漏段R2的多環(huán)芳烴主要來源于補給區(qū)的遷移和汽車尾氣的排放；雙池河區(qū)R3的多環(huán)芳烴主要來源于煤工業(yè)“三廢”的排放；排泄區(qū)R4的多環(huán)芳烴主要來源于以上三個區(qū)的遷移。R3和R4兩個區(qū)的多環(huán)芳烴濃度相對較高。為研究低環(huán)、中環(huán)、高環(huán)多環(huán)芳烴在不同介質(zhì)中占總多環(huán)芳烴的比例,我們將16種多環(huán)芳烴分為三類：2環(huán)和3環(huán),4環(huán),5環(huán)和6環(huán)。從三線圖中,我們可以看出地下水中主要以低環(huán)多環(huán)芳烴為主,高環(huán)多環(huán)芳烴未檢出；地下水懸浮物中主要以中低環(huán)多環(huán)芳烴為主,與地下水相比,4環(huán)的多環(huán)芳烴比例開始升高；而高環(huán)的多環(huán)芳烴主要集中在表層土中。中低環(huán)多環(huán)芳烴在地下水、懸浮物中的高濃度檢出表明了當?shù)厮a(chǎn)生的多環(huán)芳烴已經(jīng)通過含水層的滲漏或是含多環(huán)芳烴沉淀物的滲透進入到了地下水中,對地下水造成污染。蒽/(菲+蒽)與熒蒽／(熒蒽+芘)的比值表明研究區(qū)的多環(huán)芳烴主要來源于煤和木材的不完全燃燒,少量表層土中的多環(huán)芳烴來源于石油源。 盡管多環(huán)芳烴同分異構體間的比例可以指示其污染來源,但卻不能計算各種污染來源占多環(huán)芳烴總濃度的比重。本文根據(jù)研究區(qū)多環(huán)芳烴的可能來源,主要研究了石油源、煤的燃燒、汽車尾氣、生物質(zhì)燃燒、煤焦化等五個污染因素。這五個污染因素在總多環(huán)芳烴中的貢獻分別為2%,32%,22%,27%,18%。結果表明研究區(qū)多環(huán)芳烴的主要來源為煤的燃燒或是煤工業(yè)“三廢”的排放,占總污染來源的50%。和中國北方的許多其他城市一樣,大量煤炭能源的開采和利用,使煤成為了郭莊泉巖溶環(huán)境中多環(huán)芳烴的主要貢獻者。 2.多環(huán)芳烴的光降解過程 采用自制的光降解裝置對地表水中多環(huán)芳烴的光降解進行模擬研究。研究表明,所選的三種多環(huán)芳烴在光的作用下,降解速度非�？�,降解速率常數(shù)分別為0.031,0.045,0.017min-1,且符合一級降解動力學。三種多環(huán)芳烴的光降解半衰期都只需要幾分鐘(芴：4.17min,菲：3.79min,芘：4.77min)。由于三種多環(huán)芳烴在紫外光下不同的吸收峰數(shù)量和吸收強度(其中芘的吸收峰最少且較弱,而菲在紫外光下具有很好的吸收峰),所以三種多環(huán)芳烴的光降解速率快慢順序依次為菲芴芘。 文中探討了巖溶水中的主要陰離子(SO42-, HCO3-,NO3-)對多環(huán)芳烴光降解的影響。三種陰離子的加入都不同程度地促進了菲的光降解,表明菲在光降解過程中沒有自由基的參與。隨著HC03-的加入,芴和芘的光降解過程得到了抑制,而且當HCO3-的濃度從200增加到400mg/L時,芴和芘的光降解抑制作用增強,說明羥基自由基的氧化是芴和芘的主要光降解過程。NO3-是水體中-OH的主要來源之一,隨著NO3-的加入,芴和芘的光降解作用得到了加強,但當N03-濃度大于20mg/L時,光降解速率卻有減少,主要是因為硝酸鹽對紫外光有過濾作用,導致紫外光不能很好的進入到溶液中。S042-既能產(chǎn)生-OH,同時又能消耗-OH。研究指出,隨著S042-的加入,水體中自由基消耗反應占主導作用,抑制了多環(huán)芳烴的光降解。 當溶液中加入腐殖酸時,多環(huán)芳烴會在腐殖酸上產(chǎn)生吸附作用,阻止了多環(huán)芳烴被氧化或是光降解。同時,腐殖酸也會相應地吸收部分紫外光,影響多環(huán)芳烴對光的吸收效果。在實驗過程中,腐殖酸濃度為0,10mg/L,20mg/L時,多環(huán)芳烴的光降解速率常數(shù)分別為：芴(0.032,0.0290.026min-1)；菲(0.045,0.036,0.031min-1)；芘(0.016,0.0081,0.0042min-1)。腐殖酸的濃度對芘的光降解作用影響最大。 3.多環(huán)芳烴的吸附過程 多環(huán)芳烴菲在灰?guī)r上的吸附可以用偽一階動力學方程來描述,等溫線可以用線性吸附模型來描述。菲的吸附主要可以分為三個階段：第一階段,多環(huán)芳烴從水溶液中吸附于灰?guī)r表面；第二階段,多環(huán)芳烴從灰?guī)r表面遷移擴散到灰?guī)r的內(nèi)部顆粒上；第三階段,12h后,吸附達到平衡。多環(huán)芳烴在粒子內(nèi)的擴散是整個吸附過程的速率控制過程。根據(jù)實驗結果計算得出：菲在灰?guī)r上的吸附量為12.31μg/g。 為了研究碳酸鹽和有機碳對菲吸附的影響,實驗中,我們?nèi)コ嘶規(guī)r樣品中的碳酸鹽和有機碳。結果表明,去除碳酸鹽和有機碳后,灰?guī)r的吸附能力下降,在去除有機碳后,吸附能力下降的尤為明顯。雖然碳酸鹽在灰?guī)r中占很大的比例,但是在菲的吸附過程中起的作用較小。同時,去除碳酸鹽和有機碳后,線性分配系數(shù)從0.96下降到0.922,這是因為菲在無機成分上的吸附機理為點位吸附,是一個物理吸附過程,可以用Freundlich模型來描述,而非線性吸附。 菲的吸附量在酸性和堿性條件下都逐漸降低。傅氏轉(zhuǎn)換紅外線光譜分析儀(FTIR)檢測結果證實灰?guī)r吸附劑的表面含有大量的羥基和羧基。酸性條件時,羥基會被質(zhì)子化成OH2+基團,而且碳酸鹽會發(fā)生溶解,導致吸附點位減少,菲的吸附量降低；堿性條件時,有機官能團CH2會從灰?guī)r表面解析,而且羧基官能團開始減少,不利于菲的吸附。溶液中的離子強度較低時,鈣離子會占據(jù)部分的吸附點位,導致菲的吸附量降低,相反,當氯化鈣的濃度從0.005增加到0.1M時,系統(tǒng)的吉布斯自由能降低,表明了菲吸附量的增加。 為了探討溶解性有機物質(zhì)(DOM)對菲吸附的影響,腐殖酸(HA)與菲的相互作用,設計了三種情形進行研究：(1)HA在灰?guī)r上吸附平衡后加入菲進行吸附。結果表明,加入的菲很快的被灰?guī)r吸附,而且吸附量增大。這種現(xiàn)象表明灰?guī)r吸附HA后,仍有吸附孔位來吸附菲,而且HA和灰?guī)r間的親和力要比菲與灰?guī)r間的親和力強,所以菲幾乎不能解析出HA。(2)菲在灰?guī)r上吸附平衡后,加入HA進行吸附。結果表明,已經(jīng)吸附的菲被后加入的HA置換,菲被釋放到溶液中,HA吸附在灰?guī)r上。這種置換現(xiàn)象表明,HA對灰?guī)r上吸附位點的競爭力比菲強。(3)菲及HA在灰?guī)r上同時吸附。在這種情況下,溶液中共同存在的菲和HA在灰?guī)r上會產(chǎn)生競爭吸附。HA對灰?guī)r上吸附點位的競爭能力比菲大,親和力更強,HA會優(yōu)先吸附在灰?guī)r表面。這一結果表面,在含有可溶性有機物的污染地下水中,DOM有助于灰?guī)r對多環(huán)芳烴的吸附。 4.多環(huán)芳烴的生物降解過程 多環(huán)芳烴在含水層中的遷移、轉(zhuǎn)化及最終歸宿的重要影響因素之一就是其生物降解過程。本文從研究區(qū)受污染的地下水中篩選出了多環(huán)芳烴降解菌,經(jīng)DNA測序,鑒定其為不動桿菌屬。不動桿菌屬可以利用多環(huán)芳烴作為唯一的碳源,對其進行高效的降解。經(jīng)過6天的培養(yǎng),低環(huán)多環(huán)芳烴如萘、蒽基本被降解完全,而高環(huán)的多環(huán)芳烴也被降解了65%。在降解過程中,我們發(fā)現(xiàn)加入接種液后,微生物作用有近12小時的滯后期,說明不動桿菌屬對環(huán)境有個適應期(對酶、化學物質(zhì)毒性的適應)。多環(huán)芳烴會在生物體表面產(chǎn)生吸附,整個實驗過程中,多環(huán)芳烴的最大吸附量分別為：芴(7.5%),菲(8.5%),芘(5%)。 不動桿菌屬可以同時利用多環(huán)芳烴、葡萄糖和HCO3-作為其碳源,結果表明外加的碳源對多環(huán)芳烴的生物降解有促進作用。葡萄糖類有機碳源對多環(huán)芳烴的生物降解促進作用更強。隨著溶液中腐殖酸的加入,多環(huán)芳烴的降解速率加快,高環(huán)多環(huán)芳烴芘的降解率從50%增大到70%。這是因為腐殖酸中含有羥基官能團,在微生物作用下,能夠轉(zhuǎn)化成相應的極性基團,從而影響酶的活性。同時腐殖酸可以為微生物提供相應的營養(yǎng)元素,促進微生物的生長。 在郭莊泉巖溶水系統(tǒng)中,含多環(huán)芳烴的廢水首先在地表水中與空氣接觸,吸收足夠的溶解氧,然后進入到含水層中。所以,多環(huán)芳烴的生物降解途徑首先是通過單加氧酶或雙加氧酶對苯環(huán)進行氧化,轉(zhuǎn)化成羥基芳香族和羧基芳香族中間體。最后的產(chǎn)物為甲烷或烷烴、二氧化碳和水。值得注意的是,降解2天后,溶液中產(chǎn)生了中間產(chǎn)物2,5-(1,1-甲基乙基)-苯酚,而且該物質(zhì)不能被不動桿菌屬所降解。 論文的主要創(chuàng)新點：(1)借助PMF軟件分析揭示巖溶地下水中PAHs的來源；(2)在煤工業(yè)影響區(qū)巖溶地下水系統(tǒng)中篩選出多環(huán)芳烴的高效降解菌并探討其生物降解機理。
[Abstract]:polycyclic aromatic hydrocarbons ( PAHs ) are typical persistent organic pollutants which are carcinogenic , mutagenic and difficult to degrade , and are mainly derived from incomplete combustion of fossil fuels and biomass .

Approximately 25 % of the population in the world uses karst water as the main source of drinking water . The distribution area of carbonate rocks in China accounts for 14 % of the country ' s land area . About a quarter of the groundwater resources are distributed in karst areas . In recent years , water pollution is increasing the water quality crisis in China .

In Shanxi Benxi Formation , the formation of Upper Ordovician , SILURIAN , Devonian and Lower Carboniferous strata is absent , and the Carboniferous strata are directly deposited on the Middle Ordovician strata . Only Benxi Formation is formed between the lower coal seam and the limestone aquifer . In the Benxi Formation in Shanxi , the formation distribution pattern of " water coal symbiosis " is presented . In this way , coal is mined in the formation spaced very close to the limestone aquifer , which will have an impact on the karst water environment .

In this paper , the source , composition , migration and transformation characteristics of persistent organic pollutants in karst groundwater system and the influence of human activities on karst groundwater pollution are very necessary . In this paper , the distribution , fate and influencing factors of polycyclic aromatic hydrocarbons ( PAHs ) in environmental media are studied , and scientific basis and technical support are provided for the protection of karst water resources .

The main contents of this paper can be divided into the following aspects : 1 . Distribution and source of polycyclic aromatic hydrocarbons

In this paper , the concentration of polycyclic aromatic hydrocarbons ( PAHs ) in surface soil , groundwater and suspended matter and the sources of pollution are studied . The concentration range of total PAHs in surface soil is 622 - 87882ng / g , the concentration range of suspended matter is 4739 - 59315 ng / g , the average concentration in the groundwater is 2137 - 9037ng / g , the average concentration in each environmental medium is 17174ng / g , 1992ng / g and 5020ng / L , respectively . According to the above data , the research area is considered to have been subjected to moderate or severe pollution . The polycyclic aromatic hydrocarbon in the recharge zone R1 is mainly derived from leaching and desorption of raw coal in coal - series formation ;
The polycyclic aromatic hydrocarbons in the Fenhe leakage section R2 are mainly derived from the migration of the recharge area and the emission of automobile exhaust gas ;
The polycyclic aromatic hydrocarbons of R3 are mainly derived from the emission of " three wastes " in coal industry .
The polycyclic aromatic hydrocarbons in the two zones of R3 and R4 are relatively high . In order to study the proportion of polycyclic aromatic hydrocarbons ( PAHs ) in the low - ring , middle - and high - ring polycyclic aromatic hydrocarbons ( PAHs ) in different media , 16 kinds of polycyclic aromatic hydrocarbons are divided into three types : 2 - ring and 3 - ring , 4 - ring , 5 - ring and 6 - ring .
The proportion of polycyclic aromatic hydrocarbons ( PAHs ) in the 4 - ring is higher than that of groundwater .
The high concentration of polycyclic aromatic hydrocarbons ( PAHs ) in groundwater and suspended matter indicates that the polycyclic aromatic hydrocarbons ( PAHs ) produced in the local area have already passed through the aquifer or contain polycyclic aromatic hydrocarbons ( PAHs ) . The ratio of anthracene / ( phenanthene ) to fluoranthene / ( fluoranthene + pyrene ) indicates that the polycyclic aromatic hydrocarbons in the study area are mainly derived from incomplete combustion of coal and wood , and the polycyclic aromatic hydrocarbons in a small amount of surface soil are derived from petroleum sources .

According to the possible sources of polycyclic aromatic hydrocarbons ( PAHs ) in the study area , five pollution factors such as petroleum source , combustion of coal , automobile exhaust gas , biomass combustion and coal coking are studied . The results show that the main source of polycyclic aromatic hydrocarbons in the study area is the combustion of coal or the discharge of coal industry " three wastes " , which accounts for 50 % of the total source of pollution .

2 . Photodegradation of polycyclic aromatic hydrocarbons ( PAHs )

The photodegradation of polycyclic aromatic hydrocarbons ( PAHs ) in surface water was studied by using self - made photodegradable devices . The results showed that the degradation rate was very fast under the action of light . The degradation rate constants were 0.031 , 0.045 and 0.017min - 1 , respectively , and the degradation kinetics of three polycyclic aromatic hydrocarbons ( fluorene : 4.17min , FI : 3.79min , pyrene : 4.77min ) .

The photodegradation of fluorene and pyrene was enhanced with the addition of NO 3 - , the photodegradation of fluorene and pyrene was enhanced .

When humic acid is added to the solution , the polycyclic aromatic hydrocarbons can adsorb on the humic acid to prevent the polycyclic aromatic hydrocarbons from being oxidized or photodegradable , and meanwhile , the humic acid can absorb part of the ultraviolet light correspondingly , and influence the absorption effect of polycyclic aromatic hydrocarbons to light .
FI ( 0.045 , 0.036 , 0.031min - 1 ) ;
The concentration of humic acid had the greatest influence on the photodegradation of pyrene .

3 . Adsorption process of polycyclic aromatic hydrocarbons ( PAHs )

The adsorption of polycyclic aromatic hydrocarbons on limestone can be described by pseudo first order kinetic equation . The isothermal line can be described by a linear adsorption model . The adsorption of phenanthropic can be divided into three stages : first stage , polycyclic aromatic hydrocarbon adsorbed on limestone surface from aqueous solution ;
In the second stage , polycyclic aromatic hydrocarbons migrate from the limestone surface to the inner particles of limestone ;
The diffusion of polycyclic aromatic hydrocarbons in the particles is the rate control process of the whole adsorption process . Based on the experimental results , it is concluded that the adsorption capacity is 12.31 渭g / g on limestone .

In order to study the influence of carbonate and organic carbon on the adsorption of phenoxide , we remove carbonate and organic carbon from limestone samples . The results show that the adsorption capacity of limestone decreases after removal of carbonate and organic carbon . Although carbonates account for a large proportion in limestone , the linear distribution coefficient decreases from 0.96 to 0.922 after removal of organic carbon . This is because the adsorption mechanism of phenoxide on inorganic component is spot adsorption , which is a physical adsorption process , which can be described by Freundlich model , and nonlinear adsorption .

The results of Fourier transform infrared spectrum analyzer ( FTIR ) show that the surface of limestone adsorbent contains a large amount of hydroxyl and carboxyl groups .
When the concentration of calcium chloride is increased from 0.005 to 0.1 M , the Gibbs free energy of the system can be reduced , indicating the increase of the adsorption capacity .

In order to investigate the effect of soluble organic matter ( DOM ) on the adsorption of fife , the interaction between humic acid ( HA ) and phenanthropic acid was studied : ( 1 ) The adsorption equilibrium of HA on limestone was studied . The results showed that the adsorption equilibrium of HA on limestone was stronger than that of fi and HA .

4 . Process for the biodegradation of polycyclic aromatic hydrocarbons

The biodegradation of polycyclic aromatic hydrocarbons is one of the most important factors affecting the migration , transformation and final fate of polycyclic aromatic hydrocarbons . In this paper , polycyclic aromatic hydrocarbons ( PAHs ) are screened from the polluted groundwater in the study area . The maximum adsorption capacity of polycyclic aromatic hydrocarbons ( PAHs ) was : fluorene ( 7.5 % ) , fife ( 8.5 % ) and pyrene ( 5 % ) .

With the addition of humic acid in solution , the degradation rate of polycyclic aromatic hydrocarbon is accelerated . The degradation rate of polycyclic aromatic hydrocarbon is increased from 50 % to 70 % .

In the karst water system of Guo Zhuang - quan , the waste water containing polycyclic aromatic hydrocarbons is firstly contacted with air in surface water to absorb enough dissolved oxygen and then enter into the aquifer . Therefore , the biodegradation of polycyclic aromatic hydrocarbons is firstly oxidized by monooxygenase or dioxygenase to convert into hydroxy aromatic and carboxyl aromatic intermediates . The final product is methane or alkane , carbon dioxide and water . It is worth noting that after 2 days of degradation , the intermediate product 2,5 - ( 1,1 - methylethylethyl ) - phenol is produced in the solution , and the substance cannot be degraded by the non - moving rod .

The main innovation points of this paper : ( 1 ) The source of PAHs in karst groundwater is revealed by PMF software analysis .
( 2 ) The high - efficiency degradation bacteria of polycyclic aromatic hydrocarbons ( PAHs ) are screened in the karst groundwater system in the influence area of coal industry , and the mechanism of biodegradation is discussed .
【學位授予單位】：中國地質(zhì)大學
【學位級別】：博士
【學位授予年份】：2014
【分類號】：X523

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