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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Petroleum Related Organic Compounds in the Sediments of Kaohsiung Harbor and It's Neighboring Coastal Area, Taiwan

Hsien, Ming-Tsun 13 September 2000 (has links)
Twenty-two sediment samples were collected from Kaohsiung Harbour, and it¡¦s neighboring coastal area, Taiwan and analysed for a suite of n-C10-C35 aliphatic hydrocarbons and fifteen polycycilc aromatic hydrocarbons (PAHs). The average total concentration of n-alkanes was 4.327 £gg/g dry wt. (0.461-22.601 £gg/g dry wt.) and PAHs was 0.588 £gg/g dry wt. (0.088-1.75 £gg/g dry wt.). The highest n-alkanes and PAHs concentrations were recorded in samples from D and A stations in Kaohsiung Harbour ; stations D and A are near the outlets of Chyan-Jenn and Jen-Ai rivers, respectively. The sources of n-alkanes are probably contributed form origins of petrogenic, biogenic and higher plants according to the value of CPI (carbon preference index), chromatogram of UCM (unresolved complex materials), and n-C16 ratio etc.; while PAHs were contributed mainly from combustion in coastal areas and petrogenic in harbour areas based on the ratios of total combustion and LMW/HMW ratios. Overall, sediment concentrations of n-alkanes and PAHs in Kaohsiung coastal area were similar to literature in the world. The potential for biological effects due to PAHs is found to be low based as their individual PAHs concentrations are in general lower than effects most existed sediment quality guidelines, except Acenaphthaene, Anthracene, Benzo[a]anthracene, and Fluorene.
32

Feasibility Treatment of Diesel Fuel by Aerobic Biofiltration in Salty Environment ¡V Degradation of PAHs in Diesel

Chien, Chien-Jan 24 July 2002 (has links)
The international harbors and fishing ports in Taiwan are nearly not installed the wastewater or oil treatment facilities, which would cause the ocean pollution by the ballast and bilge water from the boats. The purpose of this research is to study the feasibility of treatment of diesel fuel and the polycyclic aromatic hydrocarbons (PAHs) in diesel by aerobic biofiltreation in salty environment. According to the experimental results, the mineral oil and PAHs in the diesel fuel present high good removal efficiencies. Both of the contaminants were decomposed fast at the first 8 hours, and then slow down. The emulsified diesel fuel were found able to be reduced 83% within 8 hours, and the concentrations of phenanthrene would found decreased from 1.5 to 0.1 mg/L. After 8 hours, we observed that the PAHs with high number of rings kept a mild diminish trend, while the PAHs with less rings exhibited arrearage and irregular indicated by some peaks appearing in the chromatography diagram of HPLC, which were not found in the diagram in the initial of test run. In conclusion, the aerobic biofiltreation systems were found able to degrade n-alkanes and PAHs in diesel fuel effectively. Thus we suggested to install the systems at the greasiness accepting facilities in the harbor. However, we still have to keep studying the influence of the interrelationship between the contaminants in diesel fuel and the environment factors.
33

Metabolism of mixtures of polycyclic aromatic hydrocarbons (PAHs) by Cunninghamella elegans

Olatubi, Oluwaseun Alfred 25 April 2007 (has links)
Polycyclic aromatic hydrocarbons (PAHs) are environmentally significant compounds due to the toxicity of some members. They are ubiquitous and are persistent bioaccumulative toxins(PBTs). The toxicity of PAHs represents a risk to human health, and there are varied risk assessment approaches to quantifying the risk posed by PAHs based on exposure routes and scenarios. PAHs are not carcinogenic until they are metabolically activated as the body attempts to break them down and forms reactive metabolites that bind to the DNA causing subsequent replication in the cells. Fundamental to assessing the risk posed by PAHs is understanding the metabolism of PAHs. Since exposure to PAHs is never to single PAHs, understanding what differences may occur in mixtures of PAHs gives accurate assessment of the dangers of PAHs. Understanding the dynamics of complex metabolism vis-a-vis single metabolism of PAHs and possible effects on the toxicity expression of PAHs is a necessary advancement to accurately impact and guide remediation strategies. Studies were carried out comparing the metabolism of the PAHs Phenanthrene (PHE), Flouranthene (FLA) and Benzo[a]pyrene (BAP) in single, binary and ternary mixtures by monitoring the disappearance of the parent compound. It was observed that PAH metabolism in the single PAH experiment differed from metabolism in both binary and ternary mixtures. Enzyme competition was evident in the metabolism of mixtures, changing significantly the metabolism patterns of individual PAHs. PAH structure was also seen to affect metabolism in mixtures and the possible creation of toxicity effects during mixture metabolism. PAH concentration changed over time with faster change during single PAH metabolism followed by ternary mixture metabolism and finally binary metabolism. These results affirm that substrate interactions must be considered in the risk assessment approaches to the dangers posed by exposure to PAHs.
34

Enrichment of Polycyclic Aromatic Hydrocarbons (PAHs) and Polychlorinated Biphenyls (PCBs) in the Low Density Sediment Particles in Kaohsiung Harbor

Hwang, Yun-jie 26 August 2008 (has links)
Polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) are persistent, ubiquitous, and toxic organic contaminants in coastal sediments. Being hydrophobic in water column, PAHs and PCBs tend to sorb rapidly on particles and eventually accumulate in sediments. Re-suspension of fine or low-density particles from the surface sediment would lead to release of the pollutants bound in sediment particles into water column. This study was to evaluate the potential of remobilization of sediment-bound pollutants into harbor water column by measuring the concentrations and compositions of PAHs and PCBs in different particle size (size fraction: 1000, 500, 250, 125 and 63 £gm) and the different density fractions (density: > 2.15, < 2.15 g/cm3) in the Kaohsiung Harbor area. The total PAH concentrations obtained from the sediments of Kaohsiung sub-channel (KH1) is higher than those of Shang-Zhu-Li fishing ferry (KH2), but it presents the opposite situation in total PCB concentrations. Total PAH concentrations are 3400 and 1700 (ng/g dw) and total PCB concentrations are 103 and 141 (ng/g dw) at sites of KH1 and KH2. PAH and PCB concentrations in the low-density fraction sediment made up more than 91% and 87% of the total concentration of the bulk sediment, respectively; while low-density fraction sediment made up only 4.3 to 7.7% of the bulk sediment in dry weight. According to the chemical fingerprinting, PAH source of Kaohsiung sub-channel (KH1) is from pyrogenic which might be from the diesel oil burning of shipping activities and containerized traffic. But the PAH sources in Shang-Zhu-Li fishing ferry (KH2) were from the combustion of coal and petroleum, which is possibly from iron and steel plant and the power plant nearby. The Toxic equivalents (TEQ) of dioxin-like PCBs in low and high-density fraction sediments were ranged from 1.1-7.6 pg-TEQ/g and 8.9-1500 pg-TEQ/g, respectively. Based on the Sediment Quality Guidelines (SQGs), only few PAH concentrations in the high-density fraction sediments were higher than the TEL value, while most of PAH concentrations in the low-density fraction sediments ranged between ERL and ERM values. This suggests the low-density sediment particles possessed higher potential of adverse effects to organisms in the aquatic environment.
35

Design and synthesis of new polyaromatic scaffolds for nano-scale applications

de Mendoza Bonmatí, Paula 15 April 2010 (has links)
Design and Synthesis of New Polyaromatic Scaffolds for Nano-Scale ApplicationsResumen: En la última década, el diseño y la síntesis de nuevos sistemas poliaromáticos han resultado de gran interés gracias a sus propiedades únicas y sus aplicaciones potenciales para la obtención de dispositivos electrónicos, y como precursores de fullerenos. Hemos estudiado el mecanismo que procede a través de la activación del enlace C-H en la reacción intramolecular de arilación directa catalizada por paladio, para la formación de sistemas biarílicos, demostrando que la reacción procede a través de la abstracción del protón asistido por la base. Aplicando condiciones optimizadas hemos preparado la molécula C60H24 que al ser irradiada da lugar a la formación del fullereno C60, mediante la reacción de arilación directa formando seis nuevos enlaces C-C en una única etapa. Además, en una colaboración interdisciplinar con físicos teóricos y experimentales, en el proyecto PicoInside, hemos participado en el diseño y la síntesis de moléculas poliaromáticas para su posterior aplicación como dispositivos electrónicos moleculares.Abstract:In the last decade, the design and synthesis of new polyaromatic scaffolds have attracted a broad interest due to their exceptional properties and their potential applications in material science like molecular electronic devices and as precursors of fullerene.Based in the intramolecular palladium-catalyzed direct arylation reaction we developed new procedures as reliable tools for the biaryl coupling through C-H activation. Insight mechanistic studies showed a proton abstraction mechanism assisted by the base rather than activation of aromatic systems towards electrophilic attack. Applying optimized reaction conditions, formation up to six C-C bonds, and in situ dehydrogenation, allows for the synthesis of C60H24, crushed fullerene in one single step that upon laser irradiation leads to C60 fullerene. Moreover, in an interdisciplinary collaboration with theoretical and experimental physicist, PicoInside project, we have participated in the design and synthesis of Y-shaped polyaromatic molecules required for single molecule electronic devices.
36

Acumulação de HPAs pela Spartina alterniflora cultivada em solo de Landfarming de indústria petroquímica

Viana, Francine Vicentini January 2008 (has links)
Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós–Graduação em Oceanografia Física, Química e Geológica, Instituto de Oceanografia, 2008. / Submitted by Cristiane Silva (cristiane_gomides@hotmail.com) on 2013-03-08T12:24:50Z No. of bitstreams: 1 2008_francine_viana.pdf: 2187831 bytes, checksum: 6e9edbfbd71025b57d9cfe607b5b3791 (MD5) / Approved for entry into archive by Bruna Vieira(bruninha_vieira@ibest.com.br) on 2013-07-15T17:32:16Z (GMT) No. of bitstreams: 1 2008_francine_viana.pdf: 2187831 bytes, checksum: 6e9edbfbd71025b57d9cfe607b5b3791 (MD5) / Made available in DSpace on 2013-07-15T17:32:16Z (GMT). No. of bitstreams: 1 2008_francine_viana.pdf: 2187831 bytes, checksum: 6e9edbfbd71025b57d9cfe607b5b3791 (MD5) Previous issue date: 2008 / Foram determinadas as concentrações de hidrocarbonetos policíclicos aromáticos (HPAs) em plantas de marismas Spartina alterniflora, cultivadas em solo contaminado (landfarming) e em solo não contaminado. As concentrações de HPAs nas plantas foram quantificadas nas raízes, hastes, folhas e folhas mortas a fim de investigar a absorção e translocamento de HPAs através da planta. Para avaliar a remoção de HPAs pela S. alterniflora as concentrações foram medidas também no solo. As plantas apresentaram desenvolvimento semelhante até os 60 dias de experimento, quando as plantas cultivadas no solo não contaminado apresentaram um desenvolvimento significativamente maior. As variações nos teores de nutrientes no solo contaminando sugerem que neste tratamento ocorreu um desenvolvimento maior de microorganismos. Tanto no tratamento com solo contaminado como no cultivo em solo não contaminado, o fator de concentração nas raízes (RCF) mostrou que as raízes apresentaram as maiores concentrações de HPAs. Os fatores de concentração nas hastes, folhas e folhas mortas (SCF, FCF e FMFC, respectivamente) indicaram que os compostos de 2-4 anéis também foram assimilados pela S. alterniflora, como fenatreno, antraceno, pireno e criseno. No solo, as concentrações deste grupo de compostos reduziram tanto no tratamento com solo contaminado quanto no solo não contaminado. Os HPAs mais recalcitrantes (5-6 anéis) como benzo(b)fluoranteno e benzo(e)pireno ficaram limitados às raízes, não havendo redução nas concentrações do solo. A utilização de Spartina alterniflora após o tratamento biológico landfarming mostrou que a presença da planta é capaz de auxiliar na remoção de alguns HPAs do solo, seja pela remoção destes através da absorção direta pela planta, seja pela estimulação da microbiota associada às raízes, que realizam biodegradação. / Polycyclic aromatic hydrocarbons (PAHs) concentrations were measured in salt marshes plants Spartina alterniflora, grown in contaminated soil with landfarming waste and in uncontaminated control soil. Plant PAHs concentrations were quantified in roots, stems, leaves and fallen leaves in order to investigate HPAs uptake and translocation through the plant. To assess HPAs removal by S. alterniflora concentrations were measured also in the soil. The plants had similar development until the 60 days of trial, when the plants grown in uncontaminated soil had a significantly greater development. The variations in nutrients levels in contaminated soil suggest that this treatment was further development of microorganisms. Both in dealing with contaminated soil and in cultivation in uncontaminated soil, the roots concentration factor (RCF) showed that the roots had the largest concentrations of PAHs. The concentration factors on stems, leaves and fallen leaves (SCF, FCF and FMFC, respectively) indicated that the compounds of 2-4 rings have also been assimilated by the S. alterniflora, as phenantrene, anthracene, pyrene and chrysene. Soil concentrations of this group of compounds reduced in both treatments with contaminated soil, as in uncontaminated soil. More recalcitrant PAHs (5-6 rings) such benzo(b)fluoranthene and benzo(e)pyrene were limited to roots, with no reduction in soil concentrations. Spartina alterniflora used after a landfarming biological treatment showed that plant presence is capable of assisting some PAHs removal from soil, either by removing these through direct absorption by the plant, either by stimulating associated roots microorganisms by biodegradation.
37

Comparing CID Dissociation of PAH Ions with iPEPICO: Implications for the RRKM Modeling of CID Breakdown Diagrams

Mohamed, Sabria Emamer Mabruk January 2016 (has links)
In the last several decades, polycyclic aromatic hydrocarbons (PAHs) have been the subject of extensive investigation due to their presumed abundance in the interstellar medium (ISM). My thesis concentrated on investigating the dissociation of ionized PAH molecules in the gas phase under similar conditions of the ISM. The twelve PAHs studied were naphthalene (NAP), anthracene (ANT), phenanthrene (PHN), cyclopenta[d,e,f] phenanthrene (CYC), pyrene (PYR), fluoranthene (FLN), perylene (PER) and coronene (COR). In addition, two dihydro PAHs were studied to examine potential intermediates in H2 catalysis, 1,2-dihydronaphthalene (DHN) and 9,10-dihydrophenanthrene (DHP), and two stabilized fragments of PAHs, acenaphthylene (ACE), fluorene-H (FLU). These ions were studied using atmospheric pressure chemical ionization (APCI) to generate the ions and the fragmentation was produced by collision-induced dissociation (CID). The CID experiments were done at different lab frame collision energies to produce breakdown curves for all fragments in each molecule. These curves were fitted by using Rice – Ramsperger-Kassel- Marcus (RRKM) theory to derive the activation energy (E0) at 0K and the entropy of activation (∆‡ S) for each reaction. The primary dissociation channel observed was H loss and this fragmentation channel was a common fragment to all PAHs molecules studied. Also, there were other fragments (CH3, C2H2, C4H2) observed in all of these molecules studied except perylene and coronene. The final step in this project was to compare these results with results derived from imaging photoelectron photoion coincidence spectroscopy (iPEPICO) reported by West and co-workers in order to determine the suitability of the APCI-CID technique for deriving reliable kinetic parameters for this class of ions.
38

Assessment of Microbial Biodegradation of Mixed Soil Contaminants at the Santa Susan Field Laboratory Using TRFLP, qPCR, and Culturing

Croyle, Kenny William 01 August 2014 (has links) (PDF)
The potential for biodegradation of contaminants in soil was assessed using an array of molecular methods, including terminal restriction fragment length polymorphism (TRFLP), quantitative polymerase chain reaction (qPCR), and traditional culturing techniques combined with sequencing of the 16S or ITS regions of the cultured bacteria and fungi. Soil was collected from the Santa Susana Field Laboratory (SSFL), which was the site of numerous liquid-propulsion rocket engine tests as well as nuclear energy research and development, which led to contamination of the soil with a wide variety of constituents. The contaminants of interest (COIs) at this site include polychlorinated biphenyls (PCBs), dioxins, polycyclic aromatic hydrocarbons (PAHs) and non-PAH petroleum hydrocarbons (PHCs). Various metals, most notably mercury and silver, are also present on the site. The purpose of this study was to determine if biodegradation is contributing to natural attenuation of contaminants in the soil, what organisms are likely causing biodegradation, and what rate(s) can be expected in the future. A literature review was conducted to investigate the chemical properties of theses COIs, their toxicity, and abiotic and biotic degradation. This research concluded that these COIs can be biodegraded if the right bacteria and/or fungi are present and active in the soil in sufficient numbers under the right conditions. Many known biodegraders of the COIs were identified in the literature review along with the most common pathways of biodegradation and degradation rates observed in field and laboratory studies. Soil was collected from 30 sample locations, with 3 sets of 10 samples containing high concentrations of one COI but low concentration of the others. PHCs and PAHs were found to be largely co-located, so 10 samples were selected for both of them. The remaining 20 samples were split evenly between PCBs and dioxins. DNA was extracted directly from all 30 soil samples and amplified using PCR for TRFLP analyses. Two soil samples were sent to Microbial Insights® for qPCR analysis. This analysis included 18 gene targets for the degradation of PHCs and PAHs, as well as the target gene for Dehalococcoides (an anaerobic dechlorinating bacteria). For each culturing a model chemical was selected to represent each COI and added to Bushnell-Haas agar plates containing no added carbon source other than the model compounds. The model chemicals were No. 2 diesel fuel for PHCs, naphthalene for PAHs, PCB #1 (monochloro) for PCBs, and dibenzofuran for dioxin. These plates were used to screen for biodegrading bacteria and fungi for each COI. Once cultured, 16S and ITS sequencing were used to identify these potential COI degraders and determine what TRFLP peak they would produce. The identity of isolated organisms was compared to information from the literature to assess the likelihood of COI biodegradation at SSFL. From the culturing experiments, 45 organisms were isolated, sequenced, and identified. The 45 included 14 unique bacteria and seven unique fungi. Of these, 10 different bacterial species and 5 different fungal species have been reported as COI biodegraders or belong to genera that contain reported COI biodegraders. TRFLP analysis revealed that the soil type has more effect on the microbial population than the presence of any of the COIs. There were no specific peaks that were significantly correlated to any specific COI. The peak distributions were fairly even, indicating a large amount of biodiversity in the microbial populations of the soil samples. The qPCR analysis revealed that SSFL soils contain significant populations of microbes that can degrade PHCs aerobically. Anaerobic PHC, anaerobic PAH, and aerobic PAH targets were not detected. A small amount of Dehalococcoides was detected in one of the samples. Collectively this study suggests that microbes present in SSFL soils are capable of biodegrading PHCs, and the genes for such biodegradation are actively being expressed. With the exception of a small population of Dehalococcoides, bacteria associated with the biodegradation of PAHs, PCBs, and/or dioxins were not detected. However, several strains of fungi were identified which have been reported to mediate cometabolic biodegradation of these compounds. Since these fungi do not require anaerobic conditions, they are more likely to contribute to natural attenuation than bacterial reductive dechlorination. Laboratory microcosm experiments are suggested for estimating rates of biodegradation at SSFL under natural attenuation conditions. Bioaugmentation and/or biostimulation methods should also be investigated in addition of natural attenuation. These microcosm experiments are currently underway in a companion study at Cal Poly by graduate student Mackenzie Billings.
39

INVESTIGATION OF TRANSPORT AND DEGRADATION PROCESSES OF POLYCYCLIC AROMATIC HYDROCARBONS IN BIOFILM

PFARR, ELENA CHRISTINE January 2004 (has links)
No description available.
40

Evaluación de la presencia de hidrocarburos aromáticos policíclicos (PAHs) en atmósfera y suelos de localidades del sudoeste bonaerense

Orazi, Melina M. 12 March 2020 (has links)
Los hidrocarburos aromáticos policíclicos (PAHs) son compuestos orgánicos persistentes que se liberan la atmósfera (principalmente desde fuentes antropogénicas, como emisiones vehiculares, combustión de pasturas, madera, combustibles fósiles, procesos industriales, refinamiento de petróleo, etc.) Se redistribuyen en la fase gaseosa y el particulado atmosférico y, desde el aire, por mecanismos de deposición llegan a los suelos, los cuales se caracterizan por se relevantes sumideros de PAHs en el medioambiente. La relevancia del estudio de los PAHs radica en sus propiedades cancerígenas, mutagénicas y tóxicas. En esta Tesis Doctoral se analizaron los 16 PAHs propuestos como contaminantes prioritarios por la Agencia de Protección Ambiental de los Estados Unidos (USEPA) estudiando su presencia en localidades del sudoeste bonaerense caracterizadas por diferente influencia del factor antrópico. Para esto, se instalaron muestreadores de aire pasivos (resina XAD-2®) y se recolectaron muestras de suelo superficial. Los PAHs se analizaron mediante cromatografía de gases - espectrometría de masas (GC-MS). Los resultados obtenidos evidenciaron la presencia de los PAHs en ambas matrices ambientales, niveles medios de Σ16 PAHs correspondieron a concentraciones bajas- moderadas con respecto a otros lugares del mundo, a su vez, los perfiles de composición fueron los esperados para cada una de las matrices analizadas (predominancia de PAHs livianos en aire y de pesados en suelo) Los análisis de las fuentes potenciales empleando los índices diagnóstico + PCA-MRL, determinaron dominancia de fuentes pirolíticas. Finalmente, el análisis de intercambio aire- suelo determinaron una tendencia neta a la deposición, siendo el suelo sumidero de los mismos. / Polycyclic aromatic hydrocarbons (PAHs) are persistent organic compounds which are released from the atmosphere (mainly from anthropogenic sources, such as vehicle emissions, combustion of pastures, wood, fossil fuels, industrial processes, oil refining, etc.). They may get redistributed into gas and particle phases to ultimately get deposited in soils/sediments which are characterized as relevant PAH´s sinks in the environment. The relevance of the study of PAHs lies in their carcinogenic, mutagenic and toxic properties; in this Doctoral Thesis, 16 PAHs (proposed as priority pollutants by the United States Environmental Protection Agency -USEPA-) were analyzed, assessing their presence in several locations at the southwest of Buenos Aires, Argentina. For this, passive air samplers (XAD-2® resin) were deployed in the field and surface soil samples were collected. PAHs were analyzed by gas chromatography-mass spectrometry (GC-MS). The obtained results evidenced the presence of PAHs in both environmental matrices, with mean levels of Σ16 PAHs in moderate to low in comparison to other worldwide locations. Composition profiles were showed a dominance of light PAHs in air while heavy ones in soil. The analysis of the potential sources using the diagnostic indexes + PCA-MRL determined an overimposition of pyrolytic sources. Finally, the air-soil exchange analysis determined a net tendency to soil depositio.

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