Petroleum contamination is ubiquitous worldwide, and poses significant health risks to humans, organisms, and the environment. Understanding the fate and behaviour of these chemicals is extremely important in order to predict and mitigate the effects of spills and accidental releases, and limit the exposure of these contaminants to humans and ecosystems. The physical and biological interactions with various petroleum hydrocarbons released into the environment were examined throughout this thesis in two different environmental settings; offshore bay sediments near Deepwater Horizon oil spill impacted sites, and an experimental aquifer injected with compounds representative of ethanol blended fuels. Stable carbon isotopes were used to identify carbon sources in a given environment as well as utilized by microbial communities during biodegradation of petroleum hydrocarbons. Patterns of n-alkanes, low levels of UCM and the lack of PAHs suggest hydrocarbons in Barataria Bay sediments were of dominantly terrestrial origin. Stable carbon isotope analysis of microbial lipids and n-alkanes indicate the presence of some petroleum residues, however there is no strong evidence of Deepwater Horizon oil. Dissolved ethanol, toluene, and MTBE were continuously injected into a pilot-scale laboratory tank simulating an unconfined sand aquifer contaminated with ethanol blended fuel. Ethanol, toluene and MTBE all experienced significant mass loss within the aquifer, which was attributed to biological degradation using stable carbon isotope analysis of residual hydrocarbons. Isotopic analysis of PLFA indicated a strong ethanol sourced signature used in microbial metabolism with some indications of an additional carbon sources such as toluene or MTBE. / Thesis / Master of Science (MSc)

In this study, phospholipid fatty acids (PLFA) and carbon isotopes were used to characterize the response of in situ microbial communities to a pilot-scale wetland reclamation project in the Alberta oil sands, and to investigate their role in carbon cycling at the reclamation site. The Sandhill Fen reclamation project in the Athabasca oil sands region (Fort McMurray, Alberta, Canada) has created an artificial freshwater fen typical of the boreal forest region in which the oil sands occur. At this site, composite tailings (CT) residue was overlain with a thick sand cap and a freshwater fen constructed on top. Biomass in the peat material of the fen was comparable to that found in natural fens, and a comparison of PLFA profiles in peat, CT from a nearby site, and undisturbed wetlands in the area showed that microbial communities in Sandhill fen were more similar to those in the CT than those in undisturbed wetlands. Bacteria dominated the biomass, including a small percentage of sulphate reducing bacteria that are of particular interest in the reclamation project. Fungi and other eukaryotes were also present. Analyses of radiocarbon in total organic carbon (TOC) and residue from solvent extraction suggest that there was petroleum present in the peat layer of the fen. A small amount of young carbon from the fen surface has been transported into the CT layer in the form of dissolved organic carbon. Radiocarbon also showed that microbes preferentially metabolized more modern carbon within the carbon sources available to them. Biomass was more related to the age of carbon in the samples than to the TOC concentration, with younger carbon in the peat associated with higher PLFA concentration. / Thesis / Master of Science (MSc)

No description available.

Previous studies have shown significant warming through the 1990s in the West Antarctic Ice Sheet (WAIS); but the records used in those studies end in early 2000, preventing trend analysis into the latest decade. Fourteen new snowpits and firn cores were collected in 2010 and 2011, which have been combined with previous cores to extend the isotopic records over WAIS. Significance of these isotopic patterns across WAIS was determined and is used to re-evaluate the warming of the West Antarctic interior over recent decades. We find that isotopic records longer than 50 years are needed to assess climate trends due to decadal variability. When assessed over periods greater than 50 years, there is a statistically significant warming trend over central WAIS. However, the isotopes in the 2000s are anomalously low in the isotopic records, which challenge the recent suggestion that the warming trend is accelerating. We attribute the isotopic low over the most recent decade to the coupling effect of anomalously low temperatures over central WAIS and associated increase in sea ice in the adjacent seas. This work strongly indicates that decadal variability and likely climate trends are both driven, at least in part, by atmospheric variability in the tropics as well as at high latitudes.

<p> The performance of a relative decay rate measurement technique was investigated. Determinations of the half-lives of the isotopes copper-64 and ruthenium-97 in various chemical states were attempted as illustrations of the use of the method. Applications of the technique are suggested.</p> / Thesis / Master of Science (MSc)

Isotopic abundances of the elements xenon, krypton, and cesium formed in the 14-Mev neutron fission of 238U have been measured using the mass-spectrometric method. The relative yields of some isotopes of krypton, strontium, zirconium, molybdenum, ruthenium, iodine, xenon, barium, cerium and neodymium were measured using a Ge(Li) detector. The ratios were normalized through isobaric nuclides, and absolute yields were obtained by normalizing the sum of the heavy-mass yields to 100%. A semi-empirical method has been developed for constructing neutron yield curves. Such a curve was used to obtain a primary-yield curve from the cumulative yields reported here. The results indicate that considerable structure might exist in the primary-yield curve at the higher excitation energy. / Thesis / Doctor of Philosophy (PhD)

The isotopic ratios S33/S32, S34/S32 and S36/S32 of different forms of sulphur in a number of meteorites have been studied. The results obtained indicate that processes of chemical fractionation have occurred in some meteorites but that the isotopic composition of the total sulphur in a single meteorite is remarkably constant from meteorite to meteorite. The relationships between the S33, S34 and S36 isotope abundances indicate that variations in these abundances due to inhomogeneities in the processes of nucleo-synthesis are not detectable. Isotopic analysis of sulphur from the iron phase of the Clark County, Pinon and Tlacotepic meteorites has shown the presence of cosmic ray induced spallation S36 and S33. These spallation results are in reasonable agreement with predictions based on production rates of other nuclei. / Thesis / Doctor of Philosophy (PhD)

This dissertation examines human mobility and population interactions at the Imperial Roman (ca. 1st–3rd c. CE) sites of Isola Sacra (SCR) at Portus, Velia in the Cilento of Italy, and Rue Jacques Brel Necropolis (JBR) in Saintes, France. Isotopes of oxygen (18Oc) and strontium (87Sr/86Sr) are used to assess instances of human mobility from the enamel of second molars (M2), providing a gauge of movement after age ~7–8 years. Nonmetric traits are employed in conjunction with isotopic perspectives to examine the nature of biological affinities and phenetic divergence between these three sites. Isotopic results of this study indicate that a significant number of individuals, including females and children, were mobile towards the sites at which they were ultimately interred, with the highest estimates of mobility provided by 18Oc seeing rates between 25%–38% across the three sites. 87Sr/86Sr results provided lower estimates of mobility ranging from zero cases at Velia to 30% at JBR, while combined 18Oc and 87Sr/86Sr analyses provided the lowest estimates of mobility ranging from zero cases at Velia to 20% at JBR. Such results suggest that a combined isotope approach may not necessarily increase the degree of mobility discrimination, bringing into question issues of regional homogeneity and overlap in 18Oc and 87Sr/86Sr values for the regions examined. A further examination of 18Oc variation in M1 vs. M2 vs. M3 for a sub-sample of 20 individuals indicates that childhood mobility was taking place at Portus. Nonmetric trait analysis provides insight to the nature of biological population similarity and divergence. Across the three sites SCR is the most similar to JBR and Velia, while Velia and JBR are the most dissimilar. The nature of these similarities suggests that overall the biological background of the people interred at JBR, SCR, and Velia is similar, but with unique regional phenetic differences indicating distinct biological populations at all three sites. Using these multiple lines of evidence this dissertation emphasizes a significant degree of mobility and population heterogeneity across the Roman landscape. It is evident from the research findings presented here that with the expanding Roman empire mobility and population interaction remained staples of Roman life. / Dissertation / Doctor of Philosophy (PhD)

In modern populations, adolescence is recognized as a pivotal part of the life course, but bioarchaeologists have not yet widely considered the experiences of adolescents in the past. This research investigates the biological and social changes during Roman adulescentia for individuals buried at Isola Sacra (1st-4th centuries CE; Italy) and Lisieux-Michelet (4-5th centuries CE; France). To investigate biological changes, this thesis identifies osteological indicators of pubertal timing and peptide analysis to assess biological sex for pre-pubertal individuals (n=264). Results demonstrate that adulescentia experienced an extended period of puberty, from nine to 20 years of age; menarche occurred around 15 years of age. Comparisons between the two archaeological sites demonstrate similar patterns of pubertal timing, suggesting similar exposure to Early Life Stress. To investigate the social changes, this research uses stable isotope analysis of incremental dentine sections in teeth, to investigate dietary change between childhood, adolescence, and adulthood. Incorporating literary sources, observed changes in diet are contextualized in relation to expected social age changes for middle-class individuals within the Roman Empire. At both sites, females exhibit a gradual dietary transition, reflecting a gradual social age change, or that diet is not an appropriate proxy for social age changes for women. For males, changing dietary patterns correspond with the beginning of adulescentia, when these young men took on new roles within their communities and underwent pubertal development. This research demonstrates that adulescentia was an extended period of biological and social change for males and females, which took on different forms depending on one’s sex/gender and social position. This research also demonstrates how investigations of adolescence can permit a more holistic interpretation of this transitional period of the life course and exposes the transitional experiences of these individuals as they come of age in the Roman Empire. / Dissertation / Candidate in Philosophy / There are kids, and there are adults, but what about those in-between? When does one become the other? These are the questions driving this doctoral research, and in applying them to the Roman Empire, I examine patterns of puberty and changes in diet, to better understand when children started to look like and eat like adults in their communities. This research demonstrates that adulescentia (i.e., adolescence) was a period of extended biological development, with puberty occurring between 9 and 20 years of age. Changes in diet, however, occurred in different ways for males and females, and across space and time within the Roman Empire, suggesting that there was not a singular experience or definition of adulescentia, but that lived experiences were more variable and nuanced than ancient literary sources suggest.

The purpose of this study was to characterize the catalytic activity of rhenium trioxide and rhenium trichloride as hydrogenation catalysts. Work was also undertaken to further study the catalytic properties of rhenium heptoxide. The activity of this latter compound had received some study in a previous project. A complete review of the literature has been made on the organic and inorganic chemistry of rhenium trioxide and rhenium trichloride. A survey of the literature on catalytic hydrogenation and the chemistry of rhenium heptoxide has also been included. Rhenium trioxide was prepared by three similar methods. The first two involved the formation of a complex between rhenium heptoxide and anhydrous dioxane. The complex was isolated and subsequently decomposed by gentle heating to give the pure trioxide. The third method employed tetrahydropyran as a complexing agent. The complex was isolated and decomposed in the same manner as previously indicated. All three methods appeared to give the trioxide in high purity, and little difference was apparent in their catalytic activities. Rhenium heptoxide and rhenium trichloride were commercially available, and thus required no special preparation. Both were generally reduced in situ to the active catalyst. In three instances rhenium heptoxicid was reduced ex situ. It was found that the in situ derived catalysts were generally more active than those derived ex situ. All reductions were carried out in a high pressure hydrogenation vessel. The reduction products were analyzed in a gas chromatograph, by refractive indicies, distillation and/or chemical extraction. Catalysts were analyzed by dissolving in concentrated nitric acid or a 30% hydrogen peroxide and ammonia solution. The resulting perrhenate was precipitated from the solution with tetraphenylarsonium chloride. Generally the analytical data obtained was not of sufficient accuracy to determine the exact chemical structure of the catalyst. The activities of the catalysts were determined by performing a large variety of hydrogenations. Results indicated that the heptoxide and trioxide derived catalysts were generally very similar in their catalytic activities. The trichloride proved to be slightly lower in its activity than the oxides. The catalysts used in this study generally required slightly more drastic conditions for the reduction of a carbonyl group than was generally necessary for a rhenium derived catalyst. The reduction of cyclohexanone was catalyzed at 123° with rhenium tioxide, while the heptoxide and trichloride required temperatures of ca. 150°. The olefinic compounds such as 1-hexene were reduced at temperatures of 95-100°, while styrene required slightly higher conditions due to its conjugation with the benzene ring. Nitro compounds and benzenoid compounds were found the most difficult to reduce with the trioxide and trichloride derived catalysts. Nitrobenzene yielded aniline only under temperatures of 226-275° depending on the catalyst used. Benzene yielded slight reduction with the trichloride catalyst at 200°. The trioxide, heptoxide and trichloride catalysts were outstanding in their ability to reduce the carboxylic acids. In most cases reduction could be effected 150-160°. The catalysts were superior to any reported in the literature for the reduction of the cargoxyl group. Most rhenium catalysts exhibit this high activity toward the carboxyl group to some extent. The oxide catalysts were also found to possess an extremely high activity toward the hydrogenation of amides and anilides. The reduction generally took place at ca. 225° giving a good yield of the primary amine in most cases tried. These catalysts compared very favorably with the better catalysts reported in the literature.