In-situ oil sands operations have been the dominant method of bitumen extraction in Canada since 2012; however, research on contaminants attributed to this method is limited in the peer-reviewed scientific literature, compared to that of open-pit mining. The Cold Lake oil sands region operates using exclusively thermal in-situ extraction techniques, raising the issue of whether oil sands activity is resulting in petroleum hydrocarbon (PHC) contamination in the absence of open-pit mines, upgraders, refineries, tailings ponds, and other bitumen processing operations. The lack of baseline contamination levels prior to oil sands development hampers debate on contamination from the oil sands industry. We address this shortcoming by using regional lake sediment cores to characterize petroleum hydrocarbons and trace their origin within the Cold Lake oil sands deposit. Petroleum hydrocarbons are hydrophobic compounds that bind to sediments, therefore persisting and accumulating in aquatic environments. This thesis examines historical levels of polycyclic aromatic hydrocarbons (PACs), petroleum biomarkers, and n-alkanes in radiometrically dated sediment cores collected from the depocenter of lakes within the Cold Lake heavy oil field. We used alkylated PACs and a suite of petroleum biomarkers to evaluate in-situ operations as potential petroleum-derived contamination sources. We predicted that similarly to open-pit mining, concentrations of PHCs in lake sediments would increase with industrial activity corresponding to proximity from in-situ operations. Like open-pit regions, alkylated PACs in Cold Lake sediments were elevated when compared to unsubstituted parent PACs and were significantly enriched in lake sediments deposited after the onset of oil sands operations. These findings imply that in-situ oil sands activity is driving the enrichment; however, diagnostic ratios and pyrogenic indices confirm a strongly pyrogenic origin in both pre-industrial and more recent sediments. When compared to a Cold Lake bitumen sample, the principal components driving PHC enrichment do not resemble bitumen. Likewise, diagnostic ratios of petroleum biomarkers and n-alkanes do not support bitumen as a significant source of hydrocarbons. PHC inputs in lake sediments are instead from terrestrial vegetation and plant waxes. These findings suggest that bitumen is not significantly contributing to petroleum hydrocarbon enrichment to lakes within the Cold Lake oil field; however, emissions from in-situ activity (natural gas burning, diesel trucks, seismic line cutting etc.) is increasingly abundant in more recent sediment. With >80 % of Canadian bitumen reserves requiring in-situ techniques for extraction, this thesis provides the first assessment of the spatial and temporal relationship between contaminant loading and proximity to in-situ oil sands operations. Additionally, this study allows for the environmental implications of open-pit mining operations to now be compared to that of in-situ techniques.

Biodegradation of petroleum hydrocarbon can be an effective treatment method applied to control oil pollution in both fresh water and marine environments. Hydrocarbon degraders, both indigenous and exogenous, are responsible for utilizing petroleum hydrocarbon as their substrate for growth and energy, thereby degrading them. Biodegradation of hydrocarbons is often enhanced by bioaugmentation and biostimulation depending on the contaminated environment and the competence of the hydrocarbon degraders present. An evaluation of the performance of the biological treatment of petroleum hydrocarbon by the hydrocarbon degrading microbes at the Brayton Fire School??s 4 million gallon per day (MGD) wastewater treatment plant was the main research objective. Samples were taken for two seasons, winter (Nov 03 ?? Jan 03) and summer (Jun 04 ?? Aug 04), from each of the four treatment units: the inlet tank, equalization tank, aeration tank and the outfall tank. The population of aliphatic hydrocarbon degraders were enumerated and nutrient availability in the system were used to evaluate the effectiveness of on-going bioaugmentation and biostimulation. Monitoring of general effluent parameters was conducted to evaluate the treatment plant??s removal efficiency and to determine if effluent discharge was in compliance with the TCEQ permit. The aeration tank is an activated sludge system with no recycling. Hydrocarbon degraders are supplied at a constant rate with additional nutrient supplement. There was a significant decrease in the population of microbes that was originally fed to the system and the quantity resident in the aeration tank. Nutrient levels in the aeration tank were insufficient for the concentration of hydrocarbon degraders, even after the application of dog food as a biostimulant. The use of dog food is not recommended as a nutrient supplement. Adding dog food increases the nitrogen and phosphorus concentration in the aeration tank but the amount of carbon being added with the dog food increases the total chemical oxygen demand (COD) and biochemical oxygen demand (BOD). An increase in the concentration of total COD and BOD further increases the nitrogen and phosphorus requirement in the system. The main objective of supplying adequate nutrients to the hydrocarbon degraders would never be achieved as there would be an additional demand of nutrients to degrade the added carbon source. This research study was conducted to identify the drawbacks in the treatment plant which needs further investigation to improve efficiency.

Concern about the possible contamination by metals, hydrocarbons and PCBs of Tees Bay and the Tees estuary, and potential sources of such materials has led to this study of surficial sediments. Surface sediment samples were collected from the Tees estuary and Tees Bay and were analysed for grain size, organic carbon content, metals, hydrocarbons (aliphatic and polyaromatic) and polychiorinated biphenyls (PCB5). The Tees estuary sediments are largely organic-rich clayey-silts, while the Bay sediments are organic-poor sands. All of the metals measured (Cd, Co, Cr, Cu, Ni, Pb and Zn) have significantly higher concentrations in the sediments of the Tees estuary than in those of Tees Bay (F<0.01), and the mean averages decrease in the order Zn > Pb> Cr> Cu > Ni > Co> Cd. These significantly higher concentrations remain apparent when the data are normalized to remove the effect of grain size variation, suggesting that the sediments of the Tees estuary are enriched in metals in comparison with the sediments of Tees Bay and that these differences are not the result of the different grain size distributions. Metal partitioning was determined by sequential extraction, using the scheme of Tessier et al. (1979) as recently modified by Ajayi and Van Loon (1989), in order to assess the likely behaviour of metals in the sediments studied. The results of the sequential extraction showed that the partitioning patterns of Cd, Cr, Cu and Zn differed between the marine and estuarine sediments. In the Tees Bay sediments the residual fraction hosted >50% of all of the metals, except Cd and Pb. In the Tees estuary, however, this fraction only accounted for >50% of the Cd, Co and Ni. Significant portions of Cd are contained in fractions 1 and 2 in both the Tees estuary sediments and those from Tees Bay. Because of the toxicity and availability of Cd this may pose a serious problem to the ecosystem. The total Pb in the sediments is also quite high, particularly in the Tees estuary, and even the small proportion in fraction 2 could cause deleterious effects. High concentrations of Cd and Pd, in Tees Bay and the Tees estuary sediments, and Cr and Zn, in Tees estuary sediments, were associated with fraction 3. Concern is directed to heavy metals associated with fraction 3 because changing environmental conditions can transfer these elements from the sediments into the aqueous phase. Cu was the only metal significantly associated with fraction 4. This fraction is likely to have an important role as a sink for trace metals, particularly for Cu and to a lesser extent Cr and Zn. Petroleum hydrocarbons, both aliphatic and polyaromatic (PAHs), were detected and quantified in all samples. The distributions of the n-alkanes, acyclic isoprenoids (especially pristane from coal), triterpanes and steranes, in most sediments from both areas, were indicative of pollution by fossil fuels. On the other hand, a few sediments from the estuary contain hydrocarbons from both biogenic and anthropogenic sources. Polyaromatic hydrocarbon assemblages observed in the samples were relatively rich in hydrocarbons having petrogenic origins. However, the presence of pyrolytic derived components was also indicated by several characteristic component composition ratios. Single PCB congeners were determined in the sediments studied. The PCB profile is fairly constant in sediments from both areas and similar to that of Aroclor 1260 and 1254. The similarity to the commercial mixtures, with only a slight enrichment of the lighter congeners, indicates that sources responsible for PCB pollution are located in the Tees area. The sediments of the Tees estuary tend to be more highly polluted, by metals, hydrocarbons and PCBs, than those of the Bay, particularly in the middle section of the estuary. However, there is a general decrease in the concentrations of these compounds from the middle to the mouth of the estuary, while within the Bay area offshore sites showed higher concentrations. Distributions of inorganic and organic constituents in the Tees Bay were significantly influenced by the organic carbon content and particle size of sediments.

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)

Esta pesquisa tem por objetivo contemplar as variáveis inerentes aos compostos, mais precisamente hidrocarbonetos totais de petróleo em função de sua disposição no meio ambiente, relacionando o comportamento associado ao seu risco toxicológico e de forma inovativa, verificar a influência de se considerar toda a gama de hidrocarbonetos de petróleo na avaliação de risco, quantificando o erro e incerteza de uma avaliação de risco clássica. O escopo de trabalho contemplou a definição da potenciometria local, definição de contaminantes de interesse, modelagens de transporte e para estes contaminantes e definição do programa de gerenciamento da área em função da inclusão de um modelo de risco toxicológico. A área encontra-se inserida em um pacote sedimentar que confere condutividades hidráulicas entre 10-4 e 10-5 cm/s. O modelo de fluxo é radial, e a velocidade linear de fluxo foi definida entre 0,5 e 8,6 m/ano. Os resultados obtidos nas campanhas sistemáticas de monitoramento indicaram que a grande maioria dos poços apresentou concentrações abaixo dos padrões ambientais. Obteve-se a constatação de contaminação efetiva nas áreas compreendidas pela Oxiteno (OXI) e Petroflex (PTX). As simulações de risco efetuadas somente para os compostos BTEX indicaram valores acima dos limites preconizados pelos órgãos ambientais somente em um cenário hipotético de utilização de água captada em área próxima ao poço PPTX 070 (Petroflex). Os demais cenários apresentam riscos dentro dos limites aceitáveis. A quantificação do risco toxicológico associado a toda a gama de hidrocarbonetos de petróleo apresentou valores mais restritivos do que as avaliações executadas para a mesma amostra quando considerou-se somente os compostos padronizados etilbenzeno, tolueno e xilenos, As variações foram de até duas ordens de grandeza no quociente de risco. A definição de metas de remediação e adoção de um programa de gestão específico deve considerar toda a gama de hidrocarbonetos de petróleo e não somente compostos padronizados. / This research aims to consider all the inherent variables to the compounds due to their disposal in the environment, relating their fate associated to their toxicological risk and verify the influence of considering all the petroleum hydrocarbons range in the risk evaluation, quantifying the uncertainty of a classic risk evaluation. The study scope considered the potenciometric trend of the site, definition of compounds of interest; fate and transport modelling for these compounds and finally the definition of the site management program associated to a model of toxicological risk. The potenciometric map illustrates a radial flow for the groundwater, with hydraulic conductivities ranging from 10-4 to 10-5 cm/s. The lineal flow velocity of groundwater was determined between 0,5 m/year and 8,69 m/year. The results obtained in the systematic monitoring campaigns indicated that the great majority of the wells presented concentrations below the environmental standards. It was verified effective contamination in the areas comprehended by Oxiteno (OXI) and Petroflex (PTX). The risk simulations performed for the BTEX compounds indicated values above the limits accepted by the environmental agencies only for a hypothetical scenery regarding explotation of water nearby the PPTX 070 well area. The other scenaries presented acceptable risk limits. The quantification of the toxicological risk associated to all the petroleum hydrocarbons range presents more restrictive values than the evaluations performed for the same water sample, when it was considered only the standardized compounds ethilbenzene, toluene and xilenes, The variations went up to two greatness orders in the risk quotient. The definition of remediation goals and adoption of a specific management program must consider all the petroleum hydrocarbons range and not only standardized compounds.

The focus of this study is on the use of bioremediation, as the primary method of decontamination for a soil contaminated with industrial waste oils. The area from which the samples were taken was used as a disposal site for oily wastewater for a period of more than 20 years. During this time the soil became severely contaminated. The site is approximately 1 acre in area and consists of three distinct soil strata: a solidified petroleum layer, a peat layer and a layer of muck and mud. This soil is approximately 96% organic matter. The purpose of this study is to determine if: given these site characteristics, is bioremediation a feasible option. Three phases were conducted to determine the usefulness of bioremediation in this situation. Phase one focused on the removal of total petroleum hydrocarbons (TPH) through nutrient addition and aeration. Phase two focused on quantifying and characterizing the reductions observed in phase one. Phase three again focused on quantifying and characterizing the reductions observed in phase one. The three phases of the study provided strong evidence that bioremediation was occurring in the soil and therefore, would be a viable means of remediation for a site with similar characteristics.

This project was a part of a study to evaluate natural attenuation (NA) as a viable remedial option for petroleum hydrocarbon (PHC) contamination at upstream oil- and gas-contaminated sites in Alberta, Canada. Laboratory mesocosms were set up using groundwater and sediment materials collected from two PHC contaminated sites (Site 1 and Site 3) in Alberta to investigate the enhancement of anaerobic PHC biodegradation by amendment of terminal electraon acceptors (TEAs, nitrate or sulfate) and/or nutrients (ammonium and phosphate). Multiple lines of evidence, including the removal of benzene, toluene, ethylbenzene and xylenes (BTEX) and CCME F1 fraction hydrocarbons (C6 to C10), rapid depletion of TEAs, the production of biogenic gases, and detection of the metabolites verified that anaerobic PHC biodegradation was occurring in both laboratory mesocosm studies. Selective biodegradation of PHCs under different reducing conditions was observed. However, there was no conclusive evidence that one reducing condition will universally favor the biodegradation of specific PHCs. In both studies, nutrient amendment showed no enhancement effects. The calculated first-order biodegradation rates in Site 1 mesocosm study ranged from 0.0032 to 0.033 d-1 for benzene, 0 to 0.028 d-1 for ethylbenzene, 0.0021 to 0.036 d-1 for m-, p-xylenes, and 0.0006 to 0.0045 d-1 for F1-BEX (F1 hydrocarbons exclduding BEX) under the tested conditions. The laboratory first-order biodegradation rates of BEX were higher than the estimated field rates, indicating the potential of enhanced anaerobic biodegradation in situ. However, when comparing the TEA amended mesocosms with the unamended controls (in which iron reduction might be the predominant process), the enhancement effects were less apparent and inconsistent. The calculated first-order biodegradation rates in Site 3 mesocosm study ranged from 0 to 0.0009 d-1 for benzene, 0 to 0.011 d-1 for ethylbenzene, 0 to 0.0016 d-1 for m- and p-xylenes, and 0 to 0.15 d-1 for o-xylene. Sulfate amendment significantly stimulated biodegradation of all xylenes and CCME F1 hydrocarbons. However, there was no definitive evidence that nitrate or sulfate amendment could enhance benzene or ethylbenzene biodegradation. / Environmental Engineering

Phytoremediation is a relatively new remediation technology that may be useful in removing organic and inorganic pollutants from soils. Much research has focused on this type of remediation in the past few years due to its potential as an efficient and cost effective technology.<p>The purpose of this project was to extensively monitor phytoremediation of diesel-contaminated field soils in the laboratory under simulated field conditions. The main objectives were: to examine petroleum hydrocarbon (PHC) transfer and degradation processes involved in phytoremediation of contaminated field soils; to compare phytoremediation of contaminated field soils with intrinsic bioremediation; and, to develop a rationally-based model that could be used as a starting point for a quantitative prediction of the rate of PHC removal.<p>To realize these objectives a series of laboratory scale experiments were designed and carried out. The experiments reproduced pole planting of hybrid poplars into diesel contaminated field soils from a former bulk fuel station. The experiments were conducted in a closed and controlled environment over a 215-230 day period with numerous aspects of the system being monitored including volatilization of PHC from the tree and soil, and microbial activity of the soil.<p>Monitoring data indicated that microbial degradation of the contaminant was by far the most influential monitored degradation pathway, accounting for 96.3 to 98.7% of the mass removed for soils containing poplars. The monitoring data also indicated a significant difference in the mass of contaminant removed from the soil for soils containing poplars compared to those without. The total estimated mass of contaminant removed varied between 8.3 and 27.7% of the initial mass for soils containing poplars and between 6.0 and 6.1% of the initial mass for soils without poplars. Lastly, using the monitoring data and the below ground biomass of the poplars from each of the experimental test cells, a rationally-based model was developed to be used as a starting point for quantitative prediction of the rate of PHC removal.

Alternative strategies involving in situ remediation technologies have been developed to assist with property clean up, however, cost-effectiveness and discrepancies in success rates and timeliness continue. The objective of my research was to critically demonstrate the application and usefulness of an in situ remediation technology at a petroleum hydrocarbon impacted site. This project was proposed as part of the research programs: Groundwater Plume Formation and Remediation of Modern Gasoline Fuels in the Subsurface and Enhancing In Situ Bioremediation at Brownfield Sites funded by the Ontario Centres of Excellence for Earth and Environmental Technologies as part of the multiphase project entitled “Enhancing in situ Bioremediation at Brownfield Sites”. This research focused on the demonstration of nitrate-enhanced in situ bioremediation at a decommissioned service station. Petroleum hydrocarbon impacted soil and groundwater is a common occurrence at gasoline distribution facilities, where toxicological effects are known for gasoline constituents of interest such as benzene, toluene, ethylbenzene and total xylenes (BTEX). These chemicals are volatile, readily soluble, and persistent in groundwater. In particular, residual contaminants present in the saturated zone were targeted for remediation as they serve as a long term source of contamination and contribute to mobile vapour phase and dissolved phase plumes. Site investigations characterized the complex hydrogeological conditions and contaminant distribution present in order to effectively design an in situ bioremediation treatment system. The addition of nitrate as a terminal electron acceptor (TEA) to an aquifer enhances in situ biodegradation of petroleum hydrocarbons, by providing the microbes with a sustainable energy source to promote cell maintenance and growth of the microbial population. The remediation strategy involved pulsed injections of remedial solution amended with a conservative bromide (200 mg/L Br-) and reactive nitrate (90 to 265 mg/L NO3-) tracers with the purpose of providing a continuous supply of TEA available to the indigenous microbial populations. Nitrate was selected as an alternative electron acceptor over the thermodynamically favoured O2 because of typical challenges encountered using O2 in bioremediation applications in addition to the existing anaerobic environment. In situ anaerobic degradation of BTEX compound using TEA amendments has been well documented; however benzene is often recalcitrant under denitrification conditions. The results of the Br- tracer breakthrough curves indicate that different preferential flow pathways were established under the transient saturated conditions present at the Site, although the behaviour of the injected remedial slug was generally consistent between the different units and the test solution was ultimately delivered to the target zone. The delivery of the remedial test solution was greatly influenced by the hydrogeological conditions present at the time of injection. The injectate was preferentially transported in the high permeability zone of sandy gravel aquifer Unit 3 under high saturated condition and background hydraulic gradients. However the seasonal decline in groundwater levels and hydraulic gradients resulted in the lower portion of Unit 4 comprised of higher permeable materials being able to transmit the test solution more effectively. Given the variable hydrogeological conditions present at the Site influenced by seasonal effects, the delivery of the remedial solution to target zones containing petroleum hydrocarbons at residual saturation is more effective under reduced saturated conditions. The delivery of TEA amended water to enhance the in situ biodegradation of petroleum contaminants is more effective when the treatment water has an increased residence time in the target remedial zone, attributed to low gradients and groundwater transport velocities at the Site. Longer residence periods enable the indigenous microbes to have increased contact time with the TEA which will be preferentially utilized to degrade the contaminants.   A reducing zone enriched with TEA in the anaerobic aquifer was established following consecutive injections of remedial test solution. A cumulative mass of 4 kg of NO3- was added to the target aquifer during the course of the remedial injections. Evidence demonstrating NO3- utilized as a terminal electron acceptor in the bioremediation of the petroleum-contaminated aquifer include: laboratory microcosm study confirming local indigenous microbial population’s ability to degrade hydrocarbons using NO3- as the TEA in addition to observed decrease in NO3- relative to a conservative Br- tracer and generation of nitrite, an intermediate product in denitrification in the pilot-scale operation. Contaminant mass removal likely occurred as Br- tracer evidence indicates that NO3- was utilized in the study area based on the inference of denitrification rates. Post-injection groundwater sampling indicate declining concentrations of toluene, however long term monitoring is recommended in order to evaluate the success of the remediation activity and assess the potential for rebound. Post-injection soil core results are unable to demonstrate the reduction in individual toluene, let alone BTEXTMB hydrocarbon levels, as a result of insufficient quantities of nitrate delivered to the target zone relative to the significant but heterogeneously distributed residual mass in the subsurface.

Phytoremediation is a relatively new remediation technology that may be useful in removing organic and inorganic pollutants from soils. Much research has focused on this type of remediation in the past few years due to its potential as an efficient and cost effective technology.<p>The purpose of this project was to extensively monitor phytoremediation of diesel-contaminated field soils in the laboratory under simulated field conditions. The main objectives were: to examine petroleum hydrocarbon (PHC) transfer and degradation processes involved in phytoremediation of contaminated field soils; to compare phytoremediation of contaminated field soils with intrinsic bioremediation; and, to develop a rationally-based model that could be used as a starting point for a quantitative prediction of the rate of PHC removal.<p>To realize these objectives a series of laboratory scale experiments were designed and carried out. The experiments reproduced pole planting of hybrid poplars into diesel contaminated field soils from a former bulk fuel station. The experiments were conducted in a closed and controlled environment over a 215-230 day period with numerous aspects of the system being monitored including volatilization of PHC from the tree and soil, and microbial activity of the soil.<p>Monitoring data indicated that microbial degradation of the contaminant was by far the most influential monitored degradation pathway, accounting for 96.3 to 98.7% of the mass removed for soils containing poplars. The monitoring data also indicated a significant difference in the mass of contaminant removed from the soil for soils containing poplars compared to those without. The total estimated mass of contaminant removed varied between 8.3 and 27.7% of the initial mass for soils containing poplars and between 6.0 and 6.1% of the initial mass for soils without poplars. Lastly, using the monitoring data and the below ground biomass of the poplars from each of the experimental test cells, a rationally-based model was developed to be used as a starting point for quantitative prediction of the rate of PHC removal.