Thesis submitted in fulfilment of the requirements for the degree of Doctor Technologiae: Chemical Engineering, Faculty of Engineering at the Cape Peninsula University of Technology - Cape Town, South Africa / Polycyclic aromatic hydrocarbons (PAHs) are one of the most common and recalcitrant environmental contaminants – known for their potential toxicity, mutagenicity, and carcinogenicity to humans. Biosurfactant application can enhance the biodegradation of PAHs. The main object of this work was to explore the novelty of biosurfactant produced by the isolated strains of Bacillus sp and Pseudomonas aeruginosa grown exclusively on Beta vulgaris, and the modification of the zeolites nanoparticles by the biosurfactant, for enhanced biodegradation of PAHs in soil. Novel biosurfactant-producing strains were isolated from hydrocarbon-contaminated environments, while several agrowaste were screened as primary carbon sources for the expression of biosurfactants, which were quantified using various standardized methods......

Polycyclic aromatic hydrocarbons (PAH) have been linked to cancer in humans. Subsequently, 16 of them were listed as priority pollutants by the Environmental Protection Agency in the Clean Water Act. The Florida manatee (Trichechus manatus latirostris) is an herbivorous endangered species that could have the potential to accumulate these compounds. The waters they inhabit have been shown to have PAH concentrations in the sediment from 0.035 μg/g w.w. (wet weight) to 0.686 μg/g w.w. PAH bioaccumulate due to their lipophilic nature and the manatee has a thick blubber layer that may allow for the accumulation of these compounds. Forty-eight archived subcutaneous manatee blubber samples were collected from Florida Fish and Wildlife Conservation Commission Marine Mammal Pathobiology lab and analyzed for 16 known priority pollutant PAH. Samples were then compared to a standard using HPLC analysis. Concentrations were found to range from 0.001 μg/g w.w. to 84.84 μg/g w.w. All 16 priority pollutant PAH were found, however not all 16 were found in any one animal. Forty-six of forty-eight manatee samples analyzed were found to have at least one form of PAH. The number of occurrences of each PAH out of 48 samples ranged from 1-19. The highest average PAH concentration was acenaphthylene with 12.60 μg/g w.w. There was no significant difference (p-value >0.10) between total, carcinogenic and noncarcinogenic PAH, with levels of 2.01 μg/g w.w., 2.18 μg/g w.w. and 1.84 μg/g w.w. respectively. No significant difference (p-value >0.10) was found between year or location of carcass recovery as well as sex of manatee. Averages ranged between 0.02 μg/g w.w. and 18.92 μg/g w.w. for year and 0.15 μg/g w.w. and 5.68 μg/g w.w. for location. Male average levels were 5.21 μg/g w.w., while female averages and perinatal averages were 1.51 μg/g w.w. and 1.147 μg/g w.w. respectively.

Polycyclic aromatic hydrocarbons (PAHs) are produced via the incomplete combustion of organic matter. They are ubiquitously present in the environment, and human exposures typically involve complex PAH mixtures in complex matrices (e.g., soil, urban air). Many PAHs are genotoxic carcinogens; exposures can augment cancer risk and reliable risk assessment of PAH mixtures is a regulatory concern. There is a paucity of in vivo genotoxicity information for most PAHs and PAH mixtures. Risk assessment of PAH mixtures assumes dose addition (i.e., additive, incremental contributions from each PAH); however, there is a lack of evidence to support this assumption. This thesis assessed the in vivo genotoxicity of 9 PAHs and 6 PAH mixtures following sub-chronic oral exposure of transgenic Muta™Mouse (i.e., adduct and lacZ mutant frequency across 5 tissues). The results revealed that PAHs and PAH mixtures induce significant levels of genetic damage; the mixtures induced very high levels of damage and mutations. Differences in the nature and magnitude of the effects in individual tissues appear to be related to the processes that govern PAH metabolism and the processing of genetic damage (e.g., repair and translesion synthesis). Scrutiny of the dose addition assumption revealed more-than-additive effects in tissues proximal to the exposure route (i.e., intestine, liver), but less-than-additive effects in distal tissues (i.e., bone marrow); however, discrepancies between the experimentally-observed and predicted responses were typically small (i.e., within 5-fold). Comparisons of cross-tissue patterns in adduct and mutant frequencies revealed that the frequency of the former is generally inversely related to that of the latter. This appears to be related to the experimental design, and the influence of repair and replication on adduct and mutant frequency. The BMD approach was employed to estimate genotoxic (i.e., adduct) potency and mutagenic (i.e., lacZ mutant) potency for all agent-tissue combinations. The results demonstrate that the mutagenic potency of PAHs and PAH mixtures is empirically related to genotoxic potency; moreover, that there is cross-tissue and cross-compound congruence in the processing of PAH-induced damage. The results obtained significantly advance existing knowledge regarding the genotoxic hazards of PAHs and PAH mixtures; moreover, the empirical relationships between genetic toxicity endpoints.

The combustion of petroleum-based fuels leads to the formation of several pollutants. Among them, soot particles are particularly harmful due to their severe consequences on human health. Over the past decades, strict regulations have been placed on automotive and aircraft engines to limit these particulate matter emissions. This work is primarily focused on understanding the fundamental behaviour of soot particles and their formation. Though the focus of this work is on soot formation and growth pathways, the study of the gas-phase combustion process was also an integral part to validate the mechanism. A reduced mechanism is developed with retaining the larger PAH species till coronene from KAUST-ARAMCO mechanism. Counterflow diffusion flames had emphasized the simulation of canonical configuration where the reduced mechanism is validated and the soot growth pathways are evaluated. The importance of the significant contribution of larger PAH species on the soot growth pathways in both SF and SFO flames is evident in this analysis. The sensitivity of these flames with respect to strain rates, dilution, and at higher pressures are analysed. Direct Numerical Simulation (DNS) of two-dimensional counterflow diffusion flames is conducted to understand the impact of vortex interactions on soot characteristics. The results indicate that the larger PAH species contributes to the soot formation in the air-side perturbation regimes, whereas the soot formation is dominated by the soot transport in fuel-side perturbation. The study is extended to simulate and compare coflow laminar flame using different statistical moment methods MOMIC, HMOM and CQMOM.

Wood contaminated by polycyclic aromatic hydrocarbons (PAH) represent a serious environmental risk. Composting seems to be an effective method for decontamination of such waste material. PAHs are degraded mainly under aerobic conditions the efficiency of composting could be strongly affected by the process conditions. This work is aimed at the comparison of PAH removal by a 340-days-long composting in laboratory scale composting pilots and a 240-days-long process in a pilot scale. To set up composting piles a "green substrate" commercially used for button-mushroom production and a grass substrate were used. The use of the grass substrate led to a higher PAHs removal (97% of the initial sum of PAHs) in comparison to the green substrate (81% of the initial sum of PAHs). Further, the effect of the size of wood particles on the PAHs removal efficiency was demonstrated. Analysis of phospholipid fatty acids showed an enhanced growth of gramm-negative bacteria and fungi during the composting processes. During the degradation process the enzyme activity of laccase was detected. The ecotoxicological test using a bioluminescent bacteria Vibrio fischeri and a seed germination test using seeds of Hordeum vulgare L. showed that probably no toxic products were formed during the PAHs degradation in these experiments.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18577号 / 工博第3938号 / 新制||工||1605(附属図書館) / 31477 / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 米田 稔, 教授 高野 裕久, 教授 清水 芳久 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第19006号 / 工博第4048号 / 新制||工||1623(附属図書館) / 31957 / 京都大学大学院工学研究科高分子化学専攻 / (主査)教授 中條 善樹, 教授 赤木 和夫, 教授 秋吉 一成 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

This investigation addresses the interrelated problems of A) Uptake and vascular transport of lipophilic chemical carcinogens, and intracellular interactions between lipoproteins and carcinogens; B) Biochemical mechanisms by which polynuclear aromatic hydrocarbon carcinogens inhibit the replicative and repair DNA synthesis in cells. The results observed in this study suggest that ingested benzo(a)pyrene (BaP) enters the gastrointestinal lymphatic drainage sequestered within lymphatic lipoproteins, and that low-density lipoproteins (LDL) play a major role in the vascular transport of BaP. BaP is taken up into cells by adsorptive endocytosis mediated by an interaction between apolipoprotein-specific receptors on the cell membrane and the specific apolipoproteins on LDL. Having entered peripheral cells sequestered within the lipid core of LDL, an electrophilic metabolite of BaP covalently binds to cellular DNA, and may interact with other cellular macro-molecules. Data presented here suggest that LDL is also absolutely required for the activation of DNA polymerase-a, which is the major enzyme of DNA excision repair necessary to correct the DNA damage caused by BaP. This study concludes that an active metabolite of the polynuclear aromatic hydrocarbon carcinogen, benzo(a)pyrene, suppresses DNA polymerase-a activity by inhibiting the binding of 2'-deoxyguanosine 5'-triphosphate to an acceptor site on the DNA polymerase-a complex with the DNA substrate, thereby competitively inhibiting interaction of 2'-deoxyguanosine 5'-triphosphate in the DNA synthetic process.

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