201 |
Dos teores de hidrocarbonetos policíclicos aromáticos (HPAs) em aguardentes acondicionadas em tonéis de carvalho / Evaluation of Polycyclic Aromatic Hydrocarbons (PHAs) concentrations in sugarcane spirits storage in barrels with different times of toast and time aged.Irene Palerma Arias Chávez 15 April 2015 (has links)
Dependendo das etapas de produção, a aguardente de cana de açúcar, pode ser contaminada por Hidrocarbonetos Policíclicos Aromáticos (HPAs) que apresentam propriedades carcinogênicas e/ ou mutagênicas. Neste trabalho se determinou os teores de HPAs em aguardentes acondicionadas em tonéis de carvalho sem tostar e tostados por 1, 2 e 3 minutos. Os dados obtidos em função do tempo de envelhecimento e do tempo de tosta do tonel foram correlacionados. Após períodos variados, as amostras foram coletadas e submetidas a processos de extração em cartuchos de SPE (C18) e analisadas por Cromatografia Líquida de Alta Eficiência (HPLC) com detector de fluorescência. Dos 16 HPAs monitorados pela Agencia de Proteção Americana (USEPA) foram analisados: Naftaleno, Acenafteno, Fluoreno, Fenantreno, Antraceno, Fluoranteno, Pireno, Benzo(a)Antraceno, Criseno, Benzo(b)fluoranteno, Benzo(k)fluoranteno, Benzo(a)pireno, Dibenzo(a,h)antraceno, Benzo(g,h,i)perileno e Indeno(1,2,3 c,d)pireno. Os HPAs nas aguardentes armazenadas, apresentaram um perfil comum, atingindo teores máximos entre o 4° e o 12° dia de armazenamento, começando a diminuir até atingir a valores em alguns casos próximos ao do Branco. Realizaram-se dois experimentos de armazenamento, o 1º experimento ao longo de 553 dias e o 2º experimento por um período de 57 dias. As amostras armazenadas no 2º experimento (tonéis re-utilizados) apresentaram teores inferiores de HPAs em relação ao 1º experimento. A soma dos teores médios máximos dos 15 HPAs, nas amostras de aguardente armazenada no 1º e 2º experimento respectivamente foram: 1 min. de tosta (27,76 -14,45 µ/L ), sem tosta (20,34 -9,02 µg/L), 2 min. de tosta (15,45 -10,38 µg/L) e 3 min. de tosta (14,25 -12,89 µg/L). Os valores do Branco para o 1º e 2 º experimento foram: 10,88 µg/L e 6,89 µg/L, respectivamente. Com respeito ao Benzo(a)pireno (BaP), os teores médios máximos alcançados em aguardentes envelhecidas em tonéis tostados por 1, 2 e 3 minutos foram respectivamente: 0,0094 µg/L, 1,401 µg/L, 0,119 µg/L e 0,051 µg/L, atingindo teores maiores que o teor do Branco do BaP (0,014µg/L). / During the different steps of production, the sugarcane spirits can be contaminated with Polycyclic Aromatic Hydrocarbons (PAHs) which have carcinogenic and/or mutagenic properties. The scope this work is to determine the levels of PAHs in aged sugarcane spirits in oak barrels with and without toasting for later correlation of results depending on the aging time and the time of the burning barrel. The samples were stored in barrels without and with toasting for 1, 2 and 3 minutes. After varying periods, samples were collected and subjected to extraction processes using SPE (C18) cartridges and analyzed by using High Efficiency Liquid Chromatography (HPLC) coupled with a fluorescence detector. We analyzed the following PAHs: naphthalene, acenaphthene, fluorene phenanthrene, anthracene, fluoranthene, pyrene, benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, dibenzo(a,h)anthracene, benzo(g,h,i)perylene and indeno(1,2,3-c,d)pyrene. PAHs in aged spirits had a common profile, reaching maximum levels between the 4th and 12th day of aging, starting to decrease the values, in some cases, lower than blank. There were two storage experiments, experiments 1 through 553 days and the 2nd experiment for a period of 57 days. Samples stored in the 2nd experiment (re-used barrels) had lower levels of PAHs compared to the 1st experiment. The sum of the maximum average levels of 15 PAHs in the samples spirit stored in the 1st and 2nd respectively experiment were: 1 min. of toast (27.76 -14.45 µ/L) without toast (20.34 -9.02 µg/L), 2 min. toasting (15.45 -10.38 µg/L), and 3 min. toasting (14.25 -12.89 µg/L). The blank values for the 1st and 2nd experiment were: 10.88 µg/L and 6.89 µg/L, respectively. With respect to Benzo(a)pyrene (BaP), the maximum average levels achieved in spirit aged in barrels toasted by 1, 2 and 3 minutes were respectively: 0.0094 µg/L, 1.401 µg/L, 0.119 µg/L and 0.051 µg/L, reaching higher levels than the blank content of BaP (0,014 µg/L)
|
202 |
I. Contorted Polycyclic Aromatic Hydrocarbons: Attempted Synthesis Of [12]circulene Derivatives Ii. Synthesis And Characterization Of Novel [1]benzothieno[3,2-B][1]benzothiophene DerivativesHollin, Jonathan 01 January 2019 (has links)
There has been increasing interest in the development of organic materials due to their unique structural and electronic properties. Organic compounds have the advantage of being able to be deposited from solution, leading to low-cost, high-area electronics production. Contorted polycyclic aromatic hydrocarbons have been shown to have potential for use in organic field-effect transistors (OFETs) and organic photovoltaic devices (OPVs) due to their supramolecular properties and charge carrier mobilities. Thiophene-based materials have also shown great promise in OFETs due to their high charge carrier mobilities, stability during device operation, solubility in organic solvents, and structural versatility.
[n]Circulenes are a class of polycyclic aromatic compounds whose shape depends on the central n-membered ring. These range from bowl-shaped when n < 6, planar when n = 6, and saddle-shaped when n > 6. The shapes of these molecules, especially for the contorted circulenes, imparts interesting and useful properties such as a polarizable π-system and coordination to fullerenes. Using methods developed in our group, synthesis of [12]circulene derivatives was attempted. Synthetic difficulties, results, and a synthetic plan to overcome these problems are presented herein.
2,7-Dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) is a thiophene-based p-type semiconducting material with one of the highest reported OFET mobility to date. Alterations to BTBT have been made to improve device processing and tune the electronic structure. However, structural alterations have generally been limited to functionalization with electron-donating groups and extension of the π-system. The lack of electron deficient derivatives has prevented further tuning of the electronic structure. Additionally, installation of strongly electron-withdrawing substituents could give BTBT n-type character as seen with perylene diimides. Several synthetic strategies to develop BTBTs with electron-withdrawing groups were explored. Limitations to developing electron deficient BTBTs as well as synthesis and characterization of novel imide-functionalized derivatives are described.
|
203 |
Using Ecosystem-Based Modeling to Describe an Oil Spill and Assess the Long-Term EffectsDornberger, Lindsey N. 15 July 2018 (has links)
The goal of the research conducted in this dissertation was to define and test methods to incorporate oil spill effects into an ecosystem-based assessment model. It was instigated by the Deepwater Horizon oil spill, an unprecedented oil spill in the United States for both depth and volume, with unknown implications for the health of the region. Using an ecosystem-based assessment model like Atlantis, with integrated oil spill dynamics, was the ideal candidate to predict long-term impacts such as decreased abundance or population recovery time. However no previous methodology existed for doing so in any ecosystem-based assessment model. Therefore, first I conducted a literature review to gather data across fish species on lesion frequency and fish body growth impacts from oil exposure. The two data sets were then fitted to four different dose-response models, and an effect threshold log-linear “hockey-stick” model was selected as the best fit and most parsimonious for both lesions and growth. Next, I conducted a similar analysis comparing macrofaunal and meiofaunal abundances to oil exposure concentrations in the Gulf of Mexico collected after Deepwater Horizon. I confirmed that these data had the domed relationship between invertebrate abundances and oil concentration observed in previous invertebrate oil studies. This domed relationship indicates that abundance increases at low to moderate oil levels, and declines at high oil levels. To drive this relationship in an Atlantis ecosystem model, three scenarios were tested in combination with oil toxicity: 1) Mississippi nutrient loading, 2) increased detritus from marine oil snow sedimentation and flocculent accumulation, and 3) predators altering their behavior to avoid oil exposure. At the Atlantis polygon resolution, only scenario 2, increased detritus from marine oil snow sedimentation and flocculent accumulation, generated the domed relationship for invertebrate abundances. Lastly, the “hockey-stick” model for fish mortality and growth was applied to both fishes and invertebrates in combination with scenario 2 for an integrated long-term assessment of the Gulf of Mexico. Newly available fish exposure data were used to generate an uptake-depuration model for this assessment. The combined effect forcings on vertebrates and invertebrates proved to have more severe long-term implications on population size and recovery than simulations with only fish forcings. Large demersal fishes, including elasmobranchs, were the most severely impacted by large biomass declines in the model spill region. Sensitivity analyses indicated that there was the potential for no recovery during 50 years of simulation in the spill region for many functional groups. Analysis of the synergy between fishing mortality F and toxicity from an oil spill identified that some guilds are more sensitive in an oil spill simulation to varied F than others. Snappers are the most sensitive to increased fishing mortality, while groupers respond the most to a reduction in fishing mortality. The invertebrate guild and small pelagic fishes responded the least to different values of F. Changing F also had implications for guild recovery – some guilds only fully recovered to control scenario biomass when F was reduced. A few functional groups were unable to survive with the combined effects of oil toxicity and increased F, and went extinct before the end of the 50-year simulation. Overall, this work provided the first framework for initial integrated modeling of oil spill impacts in an ecosystem-based assessment model, a potentially important component to future ecosystem-based fisheries management. The “hockey-stick” dose response model is applicable beyond Atlantis modeling, and can be tuned to fit specific events based on available data. I have also identified the importance of including marine oil snow sedimentation and flocculent accumulation to accurately drive the response of benthic invertebrates. Findings from the combined vertebrate and invertebrate simulations should help inform research efforts in the Gulf of Mexico and future oil spill response efforts.
|
204 |
The identification and quantitation of complex polycyclic aromatic hydrocarbon mixtures in environmental samples using comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometryManzano, Carlos A. (Carlos Andres) 27 June 2013 (has links)
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants and are mostly products of the incomplete combustion of organic material. PAHs are often found in environmental samples as a complex mixture of isomers. In addition, the same sources that produce complex PAH mixtures also produce other poorly characterized mixtures of organic compounds, commonly referred to as an unresolved complex mixture (UCM), that act as matrix interferences in the chromatographic analysis of samples.
Conventional one-dimensional chromatographic techniques, such as gas chromatography coupled to mass spectrometry (GC/MS), are not sufficient for the analysis and quantitation of complex PAH mixtures present in environmental samples due to the high degree of overlap in compound vapor pressures, boiling points, and mass spectral fragmentation patterns. Therefore, the separation and quantitation of complex mixtures of individual PAH compounds in environmental samples requires high chromatographic resolution.
Comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC��GC/ToF-MS) was used for this study. GC��GC/ToF-MS uses two different gas chromatographic columns, with different separation mechanisms, for the analysis of complex environmental samples. In theory, the peak capacity in GC��GC/ToF-MS is equivalent to the product of the individual peak capacities of each column used. However, in practice, this is rarely obtained because of the existing correlation between the two GC columns used. This dissertation is a compilation of three studies related to analytical method development for the identification and quantitation of complex PAH mixtures (including parent-PAHs, alkyl-PAHs, oxy-PAHs, nitro-PAHs, thio-PAHs, chloro-PAHs, bromo-PAHs and PAHs with molecular weight higher than 300 Da) that may be present in environmental samples using novel column combinations in GC��GC/ToF-MS.
The use of a liquid crystal column (LC-50) in the first dimension, followed by a nano-stationary phase column (NSP-35) in the second dimension, was evaluated for the separation of a standard PAH mixture containing 97 different PAHs. Two standard reference materials purchased from NIST (NIST SRM1650b ��� Diesel Particulate Matter and NIST SRM1975 ��� Diesel Extract) were used, after extraction and cleanup, for method validation and comparison between the commonly used non-polar �� polar column combination and the LC-50 �� NSP-35 column combination with high orthogonality. As part of the method validation, an aliquot of NIST SRM1975 (Diesel extract), without sample cleanup was also analyzed for PAHs, showing that the LC-50 �� NSP-35 column combination was accurate (with an average absolute percent difference of approximately 30%) for the identification and quantitation of complex PAH mixtures in environmental samples, with reduced sample preparation prior to analysis. In addition, the LC-50 �� NSP-35 column combination was used for the analysis of PAHs sorbed to polystyrene pellets deployed in an urban bay area as passive water samplers because one-dimensional GC/MS was ineffective due to the presence of a strong unresolved complex mixture (UCM) and matrix interferences. / Graduation date: 2013 / Access restricted to the OSU Community at author's request from Dec. 27, 2012 - June 27, 2013
|
205 |
Body Burden of PAHs and Cardiovascular Disease in the United StatesClark III, John Davis 31 July 2008 (has links)
Polycyclic aromatic hydrocarbons (PAHs) are environmental and occupational carcinogens that are produced by the incomplete combustion of organic material, such as from the burning of tobacco, coal, and petroleum products. In addition to causing cancer, exposure to PAHs is hypothesized to contribute to atherosclerosis and to lead to increased incidence rates of cardiovascular disease in populations. Considering the number of deaths attributable to tobacco smoke exposure, ambient air pollution, and occupational hazards, PAHs may be a significant contributor to the prevalence of cardiovascular disease in human populations. However, a clear exposure-response relationship between PAHs and measures of cardiovascular disease has not been demonstrated. While PAH exposure has been shown to be associated with indicators of cardiovascular disease in research animals, this relationship has not been studied comprehensively in human populations. Using data from the continuous National Health and Nutrition Examination Surveys (NHANES) 1999 - 2004 of a representative sample of the entire US civilian population, this study investigated predictors of total body burden of PAHs and associations between urinary metabolites of PAHs and biomarkers of cardiovascular disease in 4,492 study participants aged 20 years and older. Using various analytic approaches, this research project identified tobacco smoke exposure as a significant predictor of urinary levels of low molecular weight PAHs but not as a predictor of urinary levels of high molecular weight PAHs in a large population of individuals without known occupational exposure to PAHs. Worker occupational category was not associated with urinary levels of any PAH metabolites. The results of this study also indicate a possible association between exposure to PAHs and the development of cardiovascular disease in humans. Levels of multiple metabolites of specific PAHs, naphthalene, fluorene, and phenanthrene were significantly associated with increases in total cholesterol, triglycerides, WBC count, and C-reactive protein levels. Additionally, this study examined the utility of factor analysis for data reduction of 23 urinary PAH metabolites to two latent factors representing low and high molecular weight PAHs to streamline investigations of the associations of PAH exposures with various health outcomes. Results of this study suggest mechanisms by which PAH exposure contributes to the burden of cardiovascular disease on human populations and the methods by which human body burden on PAHs can be measured.
|
206 |
Preparation and characterization of plasma-fluorinated epitaxial grapheneSherpa, Sonam Dorje 14 March 2013 (has links)
The discovery of unique properties of graphene has led to the development of graphene for a variety of applications like integrated circuits, organic electronic devices, supercapacitors, sensors, and composite materials. Fluorination of graphene enables control of its physical, chemical, and electronic properties. Our initial studies demonstrated the viability of sulfur hexafluoride plasmas to fluorinate epitaxial graphene as a safer alternative to the commonly reported techniques of fluorination that include exposures to fluorine and xenon difluoride gas. Formation of carbon-fluorine bonds after SF6 plasma-treatment was confirmed by x-ray photoelectron spectroscopy. Raman spectroscopy and low-energy electron diffraction studies suggest that the framework of sp2-hybridized carbon atoms remains intact after the plasma-treatment. Increase in work function after the fluorination was determined by ultra-violet photoelectron spectroscopy. The findings of our subsequent investigation to controllably modify the work function of epitaxial graphene via plasma-fluorination indicate that the work function of fluorinated epitaxial graphene is controlled by the polarity of carbon-fluorine bonds. Further studies to investigate the effect of the surface topography of epitaxial graphene on the work function of plasma-fluorinated epitaxial graphene were performed using scanning Kelvin probe microscopy (SKPM). The results of SKPM characterization of plasma-fluorinated epitaxial graphene demonstrated that the increase in the work function of epitaxial graphene after plasma-treatment is independent of its surface topography, but non-uniform fluorination may result from non-uniformities in plasma density.
|
207 |
Interactions Between Environmental Factors and Polycyclic Aromatic Hydrocarbons (PAHs) in Developing Fish: Molecular and Developmental ImplicationsFleming, Carrie January 2010 (has links)
<p>Aquatic systems are impacted by a wide variety of natural and anthropogenic stressors. Laboratory studies often focus on impacts of a single stressor, ignoring how these stressors may interact. This dissertation focuses on the interactions between polycyclic aromatic hydrocarbons (PAHs) and two physical stressors (hypoxia and solar radiation). PAHs are ubiquitous environmental pollutants that occur in the environment as complex mixtures, the components of which may interact. Some PAHs are agonists of the aryl hydrocarbon receptor (AhR), which regulates expression of a number of genes (such as CYP1A) involved in metabolism, often of the same compounds that induced the AhR. PAHs that are AhR agonists have been shown to interact synergistically with PAHs that inhibit activity of CYP1A, inducing developmental deformities in fish. AhR shares a dimerization partner, the aryl hydrocarbon receptor nuclear translocator (ARNT), with the protein responsible for regulating hypoxia-induced gene expression, hypoxia-inducible factor 1á (HIF1α), possibly resulting in competition between the two pathways. Competition would result in decreased induction of CYP1A under hypoxic conditions, possibly resulting in synergistic embryonic toxicity between AhR agonist PAHs and hypoxia. In this dissertation, the results are presented of experiments regarding the occurrence of AhR/HIF1α crosstalk in fish and the developmental consequences of co-exposure to hypoxia and PAHs. In vitro testing revealed competition for ARNT in which HIF1α appeared to out-compete AhR. Induction of an AhR-responsive luciferase reporter by several AhR agonists (benzo[a]pyrene (BaP), benzo[k]fluoranthene (BkF), and polychlorinated biphenyl (PCB126)) was reduced under hypoxia and this effect was eliminated by overexpression of ARNT. Induction of a HIF1α-responsive reporter was unaffected by BkF and PCB126. BaP caused an ARNT-independent decrease in both basal and induced HIF1α reporter activity. Attempts to verify this crosstalk pattern in vivo revealed that BaP-induced CYP1A expression was further increased under hypoxic conditions. Induction of hypoxia-inducible genes VEGF and LDHa were unaffected by BaP. The effect of hypoxia on CYP1A expression was not repeated with BkF or pyrene (PY) and the exact conditions that result in hypoxic changes in CYP1A expression remain to be determined. Embryonic toxicity in zebrafish (Danio rerio), including pericardial edema, heart malformations, and death were synergistically induced by hypoxia and BaP, BkF or complex, environmentally relevant PAH mixtures. There was no effect of hypoxia on PCB126 toxicity and hypoxia protected from the pericardial edema induced by PY. CYP1A knockdown mimicked the effects of hypoxia on BkF and PY toxicity and even further exacerbated BkF toxicity under hypoxic conditions, suggesting a role for metabolism in the toxicity. Additionally, since two CYP1A inhibitors (fluoranthene (FL) and á-naphthoflavone (ANF)) had been previously reported to interact synergistically with hypoxia, three other CYP1A inhibitors (dibenzothiophene, carbazole and 2-aminoanthracene) were tested. None of them induced toxicity in combination with hypoxia, indicating that CYP1A inhibition was not the reason for the interaction of FL and ANF with hypoxia. </p><p>A second stressor known to interact with PAHs to induce toxicity is solar radiation. While most studies of the effects of solar radiation on PAH toxicity have focused on the effects of UV light on PAHs already absorbed by an organism (photoactivation), less attention has been paid to the toxic effects of photomodified PAHs. We exposed carbazole to ambient sunlight and subsequently exposed developing zebrafish to the resulting mixture. Photo-exposed carbazole caused developmental toxicity including edema, heart malformations, craniofacial malformations and death that were not caused by parent carbazole; these effects were severely exacerbated by hypoxia and significant mortality was also observed. Additionally, photo-exposed carbazole induced expression of CYP1A and GSTp, likely resulting from agonism of the AhR and toxicity of this mixture was alleviated by morpholino knockdown of AhR. Some photoproducts were identified, but none of them appeared to be involved in the toxicity or supposed AhR induction observed with photoexposed carbazole. The results of these experiments underscore the importance of consideration of the interactive effects of physical and chemical stressors when assessing risks to wildlife populations inhabiting polluted areas.</p> / Dissertation
|
208 |
Concentrations and distribution of polycyclic aromatic hydrocarbons(PAHs) and polychlorinated biphenyls(PCBs) in Kaohsiung HarborChen, kai-ting 18 March 2010 (has links)
This study investigated the concentrations of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in the particulate and dissolved phase, as well as concentrations of PAHs in the sediment in Kaohsiung Harbor lagoon. Sources of PAHs in the water column were determined by isomer ratios, hierarchical cluster analysis (HCA) and principal components analysis (PCA). The net and annual fluxes of PAHs were calculated after a lagoon-wide water sampling campaign and compared with those found in a previous study (Fang, 2007) in which data from only one water sampling station was used.
¡@¡@In rain season, total PAH concentrations ranged from 21.6 to 36.2 ng/L for water samples, with dissolved and particulate phase concentrations ranged from 15.5 to 27.2 ng/L and from 3.4 to 8.6 ng/L, respectively. In dry season, total PAH concentrations ranged from 13.2 to 31.5 ng/L for water samples, with dissolved and particulate phase concentrations ranged from 8.0 to 21.1 ng/L and from 5.3 to 10.5 ng/L, respectively. Total PAH concentrations were found higher in rain season than in dry season. The highest total PAH concentration in dry season was observed in Chianjen River estuary. Relatively high PAH concentrations were also observed in these southern stations of Kaohsiung Harbor because of their location near Dalin industrial park. Total PAH concentrations ranged from 81.7 to 2279 ng/g for sediment samples, with average of 895 ng/g.
The correlations between PAH concentrations and organic carbons, water temperature, salinity and suspended particles were also examined in this study. PAH concentration in dissolved phase was negatively correlated with water temperature (p<0.05). PAH concentration in sediment was positively correlated with organic carbons (p<0.05), and negatively correlated with median diameter (p<0.01). The logKoc¡ÐlogKow relationship in rain and dry season was compared with literature. It was found that the logKoc values were higher than those reported in literature, suggesting that soot particles might play an important role in the transport and distribution of PAHs in the study area.
In rain season, PAHs in dissolved phase were mainly from pyrogenic origins; while mainly from petrogenic origins in particulate phase. In contrast, in dry season, PAHs in dissolved phase were mainly from petrogenic origins; while mainly from pyrogenic origins in particulate phase. In addition, it was found, relatively, that petrogenic pollution was introduced maily from the northern area of the lagoon.
In rain season, total PCB concentrations ranged from 1.1 to 2.7 ng/L for water samples, with dissolved and particulate phase concentrations ranged from 0.42 to 2.1 ng/L and from 0.24 to 1.4 ng/L, respectively. In dry season, total PCB concentrations ranged from 0.54 to 1.3 ng/L for water samples, with dissolved and particulate phase concentrations ranged from 0.20 to 0.74 ng/L and from 0.32 to 0.76 ng/L, respectively.
The direction of net fluxes of PAHs in this study are from water to air (net volatilization) in summer. In winter, however, the absorptive PAH fluxes obtained for four to six-ring PAH, such as fluoranthrene, chrysene + triphenylene and benzo[a]anthracene, indicating that PAHs were absorbed into surface waters. According to our results, it was suggested that the results from previous study (Fang, 2007) might underestimate the net fluxes of Pyrene and total fluxes in dry season. The annual fluxes of PAHs estimated in this study were 212 mg/m2 /year and 5.7 kg of PAHs were emitted annually from the harbor lagoon surface waters to the ambient atmosphere.
|
209 |
Factors affecting atmospheric Polycyclic Aromatic¡@Hydrocarbons in Kaohsiung coast by GMDHChiou, Guo-Yang 18 August 2010 (has links)
Coastal atmospheric concentrations of polycyclic aromatic hydrocarbons (PAHs) were measured at top of a building on campus of the National Sun Yat-sen University of Kaohsiung. Concentrations of 52 PAH compounds were analyzed in both gaseous and particulate phases in air samples collected from May 2008 through April 2009. PAHs diagnostic, Hierarchical Analysis (HCA) and Principal Component Analysis (PCA) were employed to determine the potential sources of PAHs. The Group Method of Data Handling (GMDH) was applied to relate atmospheric PAH concentration to air quality variables like SO2 and O3, as well as meteorological conditions like precipitation and temperature.
During the sampling period the mean of total PAH concentrations was 14.2 ng/m3. Over all, PAH concentrations in winter were higher than summer, with the lowest concentrations of PAHs occurred in June (2.22 ng/m3), while the highest occurred in January (32.4 ng/m3). The night-time concentrations of PAHs are higher than daytime. The 2, 3-ring PAHs were mostly present in the gaseous phase, 4-ring were dominant in the gaseous phase, while 5, 6, 7-ring PAHs were mostly present in the particulate phase. During the Ghost festival and Asian dust storm events, atmospheric concentrations of PAHs and PAHs/TSP ratios were both found increased.
Meteorological conditions, such as temperature and relative humidity, may strongly affect PAH concentrations, the gaseous and particulate PAHs correlate significantly with SO2, NOx, and PM10. Result from analyses of diagnostic rations, HCA and PCA, indicates the major sources of PAHs include gasoline and diesel exhaust.
By using GMDH, a reasonable appraisal index was obtained for the pattern forecast potency with the meteorological and air quality variables. The GMDH algorithm obtained during 2008~2009 was tested in predictions and compared with what measured in 2007~2008.
|
210 |
Assessment of Butyltins and Polycyclic Aromatic Hydrocarbons Contamination of Harbor SedimentsChen, Chih-Feng 30 August 2010 (has links)
The distribution of butyltin compounds (BTs) in the sediments and seawater, at the river outfalls, fishing ports, shipyards, and industrial zone docks of Kaohsiung Harbor, Taiwan were investigated. Twenty sediment and seawater samples were collected from various locations in the Harbor in 2006, and analyzed for monobutyltin (MBT), dibutyltin (DBT), and tributyltin (TBT). Results showed that the concentration of total BTs varied from 1.5 to 151 ng/g in sediment samples, with TBT being the major component of the sediment samples. This suggests that sediments could be the most possible sink of TBT brought by the sorption mechanism. The concentrations of BTs ranged from 9.7 to 270 ng/L in seawater samples, whereas DBT and MBT, the degradation byproducts of TBT, were mainly the most abundant BT compounds of the seawater samples. This indicates that the abiotic or biotic degradation potential of TBT was significant. Spatially, the highest concentrations of BTs were observed in both water and sediment samples collected from the shipyard and fishing port areas. This indicates that the shipping related activities (e.g., navigation, ship repair, and ship building), would contribute most of BTs in the environment. Results show that the concentrations of degradation products (DBT and MBT) were related closely to temperature, salinity, dissolved oxygen (DO), and chlorophyll-a of the seawater. This implies that seasonal changes of the water parameters controlled the degradation of TBT in seawater. The observed levels of BT compounds in both seawater and sediments were much higher than those required to induce toxic effects on marine organisms suggesting that appropriate TBT control strategies should be taken in Kaohsiung Harbor.
Sediment samples were collected from the river outfalls, fishing ports, shipyards, and industrial zone docks of Kaohsiung Harbor, Taiwan to evaluate the distribution of polycyclic aromatic hydrocarbons (PAHs) in sediments. Collected sediment samples from 12 locations were analyzed for 17 different PAHs, organic content, and grain size. The results show that the total PAH concentrations varied from 472 to 16,201 ng/g dry wt, with a mean concentration of 5,764 ng/g dry wt The highest PAH concentrations were from the industrial zone docks situated in south Kaohsiung Harbor, ranging from 8,788 to 16,201 ng/g dry wt Among those sediment samples, the 5-, 6-ring PAHs were predominant PAH congeners in sediments, ranging from 42 to 71%. However, the dominant PAH congeners were 2-, 3-ring PAHs (37 to 42%) collected from steel industrial zone docks. This indicates that the sources for the PAH contamination at steel industrial zone docks were different from the other zones in Kaohsiung Harbor. According to the diagnostic ratios, the possible source of PAHs in the industrial zone dock could be coal combustion while in the other zones it could be petroleum combustion. The total PAH levels were expressed as the total toxic equivalent (TEQcarc). The total TEQcarc varied from 55 to 1,964 ng TEQ/g dry wt. Higher total TEQcarc values were found at industrial zone docks (from 1,404 to 1,964 ng TEQ/g dry wt). As compared with the US Sediment Quality Guidelines (SQGs), the observed levels of PAHs at industrial zone docks exceeded the effects range low (ERL), and could thus cause acute biological damage. However, the lower levels of PAHs at the other zones would not exert adverse biological effects. Results would be helpful in developing strategies for sediment remediation in Kaohsiung Harbor.
|
Page generated in 0.0384 seconds