The oil sands, located in north-eastern Alberta, are one of the largest deposits of oil worldwide. Because the Alberta Environmental Protection and Enhancement Act prohibits the release of oil sands process-affected material into the environment, industry is storing vast quantities of tailings on mine lease sites. The oil sands industry is currently accumulating tailings waste at a rate of >105 m3/day, for which reclamation strategies are being investigated. Naphthenic acids (NAs) have been identified as the most toxic component of oil sands tailings as they are considered acutely toxic to a variety of biota, and are therefore a target contaminant for tailings pond reclamation strategies. Current literature based on Microtox® assays (marine bacteria Vibrio fischeri) suggests that lower molecular weight NAs are more toxic than higher molecular weight NAs. The following thesis involves the utilization of NA fractions and their relative toxicities to determine if NA toxicity is related to NA molecular weight. A previous study generated an oil sands-derived naphthenic acid extract (NAE), which was fractionated by distillation at stepped temperatures, yielding five fractions with increasing median molecular weights (Daltons). In the present study, the same extract and five fractions were utilized. To expand on the earlier characterization which involved a low resolution electrospray ionization mass spectrometry (ESI-MS), the whole extract and five fractions were analysed using electrospray ionization high-resolution mass spectrometry (ESI-HRMS) and synchronous fluorescence spectroscopy (SFS). Mean molecular weights were generated for each fraction, and an increase in molecular weight with increasing fraction number was confirmed. Respective mean Daltons and relative proportions for each fraction are as follows: 237 and 11.9 % (fraction 1), 240 and 32.3% (fraction 2), 257 and 33.4% (fraction 3), 308 and 16.8% (fraction 4), and 355 and 5.6% (fraction 5). When chemical analyses of fractions were compared, it was determined that structures contributing to increased molecular weight included increased cyclic structures (up to 7-ring structures), aromaticity (mono- and diaromatics), nitrogen, sulfur, and oxygen heteroatoms, and dihydroxy/dicarboxy compounds. In addition, characterization data suggested the presence of NAs exhibiting estrogenic structures. Following chemical characterization, NA fractions were subject to embryo/larval bioassays using two fish species: Oryzias latipes (Japanese medaka) and Pimephales promelas (fathead minnow). Endpoints evaluated were mortality, time to hatch, hatch length, and abnormalities. Results suggest that relative NA fraction toxicity is not related to molecular weight, as no trend relating mean Dalton weight to toxicity was observed for any endpoint in both species. Acute toxicity data indicated differences between fractions as high as 2-fold, although results were species-dependent. Fraction 1 displayed the lowest potency (highest LC50) for both Japanese medaka (0.291 mM) and fathead minnow (0.159 mM). Fractions 3 and 2 for Japanese medaka (0.149 and 0.157 mM, respectively), and fractions 5 and 2 for fathead minnow (0.061 and 0.080 mM, respectively) displayed the greatest potencies for mortality (lowest LC50). When fraction LC50s for Japanese medaka were compared to the whole NAE (0.143 mM), the mid molecular weight fractions (fractions 2 and 3) appeared most similar to the whole NA. . In terms of relative toxicity and proportion, constituents in the mid molecular range fractions (2 and 3) likely represent greater risk compared to other fractions, and further chemical and toxicological characterization of constituents within these fractions is warranted particularly for long-chained, monocarboxylic acids, with low aromaticity. Japanese medaka and fathead minnow varied in their sensitivity and their relative response to different fractions. In general, fathead minnow were more sensitive than Japanese medaka based on lower estimates of LC50 and threshold (growth) values in addition to the presence of developmental abnormalities (predominately yolk sac edema) associated with a few of the fractions. Compared to differences in toxicity between fractions for a given species (>2-fold for fathead minnow), there was more variability between species for a given fraction (> 3-fold for fraction 5). Also, the relative toxicity of fractions as indicated in the present study is contrary to the results generated using Vibrio fischeri for the same fractions. Thus, there is a need for multi- endpoint and species toxicity evaluations to assess the efficacy of remediation and reclamation options for reducing toxicity of oil sands tailings.

In order to determine the degradation of Naphthenic Acids (NAs) in oil sands process-affected water (OSPW), a series of semi-batch ozonation experiments have been conducted resulting in a maximum reduction of NAs greater than 99%. Compared to the high NAs removal, the reduction of both COD and DOC was much lower under the same conditions. Following ozone treatments of approx. 80 mg/L, the cBOD5 and cBOD5/COD tripled as compared to original OSPW measurements, suggesting ozone-treated OSPW has a higher biodegradability. The ozone treatments also detoxified the OSPW; with an ozone treatment of approx. 100 mg/L, the treated OSPW showed no toxicity using the Mircotox® bioassay. Additionally, the coke-treated OSPW, treated using a coke/water slurry process, was found to be non-toxic with an ozone treatment of approx. 20 mg/L. The results obtained during this study shows the great potential ozonation may offer as a possible water treatment application for oil sands water management. / Environmental Engineering

Thesis (M.S.)--Texas State University-San Marcos, 2007. / Vita. Includes bibliographical references (leaves 52-54).

Thesis (M.S.)--Texas State University-San Marcos, 2007. / Vita. Includes bibliographical references (leaves 52-54).

Nynas AB is a company that refines oil  for different applications such as insulating oils  for the electrical industry and base oils for both the lubricant and chemical industry. Different types of base oils are produced for the lubricant industry in order to provide required properties such as good viscosity, solvency, volatility, etc. But sometimes, the oils produced in the refineries (known as “straight cut” oils) do not have the all properties required by a customer, and a way for achieving those properties is to blend different straight cut base oils. To save money and time, empirical correlations are used to facilitate the prediction of the properties of those blends.Those correlations are adapted to products from a single site produced from certain crude oils. The company has recently decided to introduce a new stream of products with different characteristics, which means that the new properties of the products and blends can not be predicted by using the existing empirical correlations. The objective of this project was to analyze blends containing these new products and find the new correlations. The names of the oils are classified information and were renamed in the report and also number of the tables with result in appendices has been reduced to protect Nynas AB.  The correlations were surprisingly good for most of the blends. The differences between the values obtained by the blending program (which was calculating the properties) and the experimental values were very small. But the calculated values for properties such as flash point and pour point, were quite different from the experimental ones for some of the samples. Finally, there was one type of blends, between the Naphthenic oil 2 (N 2) and Paraffinic oil B (P (B)), were it was not possible to get any results with the blending program, because the viscosities at 40 °C of those oils (N 2 and P(B)) were too similar. As mentioned before, the property that was most difficult to predict was the pour point, specially for blends containing paraffinic oil blend with a naphtenic oil. However, suggestions were made based on the experimental values of how to get correlations based on. Anyhow, empirical correlations were developed based on the experimental data.

Naphthenic acids (NAs) are toxic organic acid compounds released during the caustic hot-water extraction of crude oil from oil sands in north-eastern Alberta, Canada. NAs subsequently accumulate in the large volume of oil sands process water (OSPW) produced daily by oil sands operations. The complexity of dealing with a mixture of over 200 individual NA compounds, combined with their acute aquatic toxicity and large volume of production has made them an emerging pollutant of concern for western Canada. The following thesis outlines a variety of experiments designed to determine the potential to use wetland plants to enhance the dissipation of NAs from OSPW (phytoremediation). <p>Investigations were carried out with three native emergent macrophyte species cattail (<i>Typha latifolia</i>), common reed (<i>Phragmites australis </i>subsp. <i>americanus</i>), and hard-stem bulrush (<i>Scirpus acutus</i>) to see if they enhanced the dissipation of NAs from a hydroponic system. Dissipation of NAs (at 30 mg L-1 and 60 mg L-1) was investigated with both a commercially available NA mixture as well as with a NA mixture extracted from the OSPW. Dissipation of NAs was also investigated under the different ionized forms of NAs (ionized, pH = 7.8; and non-ionized, pH = 5.0) to better elucidate the mechanisms of NA uptake and toxicity in plants. Phytotoxicity of NAs was investigated in hydroponic experiments through fresh weight gain and evapotranspiration was monitored throughout the experiment by water uptake. Commercially available NA mixture was more phytotoxic than oil sands NAs mixture. As well, NAs were found to be more phytotoxic in their non-ionized form therefore indicating that they may be taken up through an ion-trap‟ mechanism. However despite this, no significant dissipation of total NAs was observed from planted hydroponic systems. Nevertheless there was a significant change in the distribution (percent abundance) of individual NA families of certain size. These changes were related to the one- and two-ring NA compounds (Z = -2 and Z = -4). Despite not detecting any dissipation of total NAs from the systems, plants were able to reduce the toxicity of a NA system over 30 days by 45% as determined by Daphnia magna acute toxicity bioassays; a 11% greater reduction than unplanted systems.<p> Studies were also conducted investigating the microbial community inhabiting cattail roots exposed to NAs. It was observed that the rhizosphere community changed with NA exposure, with a general increase in potentially pathogenic bacteria and a decrease in bacteria previously found to be beneficial to plant growth. The observed microbial community change could be an indirect effect of the Phytotoxicity experienced by aquatic macrophytes exposed to NAs. Synchrotron-sourced, fourier transform microspectroscopy analysis of root cross sections revealed that there were significant physiological changes to those roots exposed to NAs. These changes were identified as being cell death in the plant root epidermis as well as a change in the chemistry of parenchyma cells in the root pith. It is not known if these changes are a direct effect of NAs to the plant or due to changes of the associated rhizosphere community in the roots or some combination of both these factors.

Naphthenic acids (NAs) are toxic organic acid compounds released during the caustic hot-water extraction of crude oil from oil sands in north-eastern Alberta, Canada. NAs subsequently accumulate in the large volume of oil sands process water (OSPW) produced daily by oil sands operations. The complexity of dealing with a mixture of over 200 individual NA compounds, combined with their acute aquatic toxicity and large volume of production has made them an emerging pollutant of concern for western Canada. The following thesis outlines a variety of experiments designed to determine the potential to use wetland plants to enhance the dissipation of NAs from OSPW (phytoremediation). <p>Investigations were carried out with three native emergent macrophyte species cattail (<i>Typha latifolia</i>), common reed (<i>Phragmites australis </i>subsp. <i>americanus</i>), and hard-stem bulrush (<i>Scirpus acutus</i>) to see if they enhanced the dissipation of NAs from a hydroponic system. Dissipation of NAs (at 30 mg L-1 and 60 mg L-1) was investigated with both a commercially available NA mixture as well as with a NA mixture extracted from the OSPW. Dissipation of NAs was also investigated under the different ionized forms of NAs (ionized, pH = 7.8; and non-ionized, pH = 5.0) to better elucidate the mechanisms of NA uptake and toxicity in plants. Phytotoxicity of NAs was investigated in hydroponic experiments through fresh weight gain and evapotranspiration was monitored throughout the experiment by water uptake. Commercially available NA mixture was more phytotoxic than oil sands NAs mixture. As well, NAs were found to be more phytotoxic in their non-ionized form therefore indicating that they may be taken up through an ion-trap‟ mechanism. However despite this, no significant dissipation of total NAs was observed from planted hydroponic systems. Nevertheless there was a significant change in the distribution (percent abundance) of individual NA families of certain size. These changes were related to the one- and two-ring NA compounds (Z = -2 and Z = -4). Despite not detecting any dissipation of total NAs from the systems, plants were able to reduce the toxicity of a NA system over 30 days by 45% as determined by Daphnia magna acute toxicity bioassays; a 11% greater reduction than unplanted systems.<p> Studies were also conducted investigating the microbial community inhabiting cattail roots exposed to NAs. It was observed that the rhizosphere community changed with NA exposure, with a general increase in potentially pathogenic bacteria and a decrease in bacteria previously found to be beneficial to plant growth. The observed microbial community change could be an indirect effect of the Phytotoxicity experienced by aquatic macrophytes exposed to NAs. Synchrotron-sourced, fourier transform microspectroscopy analysis of root cross sections revealed that there were significant physiological changes to those roots exposed to NAs. These changes were identified as being cell death in the plant root epidermis as well as a change in the chemistry of parenchyma cells in the root pith. It is not known if these changes are a direct effect of NAs to the plant or due to changes of the associated rhizosphere community in the roots or some combination of both these factors.

The processing of bitumen in the Athabasca oil sands region (AOSR) produces extensive volumes of oil sands process-affected water (OSPW) and tailings, which are stored within tailings ponds and settling basins to promote the consolidation of solids and the recycling of water. Oil sands operators are actively investigating dry and wet reclamation strategies in order to reduce their inventory of tailings and return disturbed land back to its original state. An important component of the reclamation of tailings is understanding the environmental fate of naphthenic acids (NAs), which are considered the most toxic constituents of OSPW and tailings. However, since NAs exist as a complex mixture comprised of thousands of compounds from dozens of chemical classes, the characterization of NAs within environmental samples poses significant challenges to analytical chemists. This dissertation is focused on the characterization of naphthenic acids by comprehensive two-dimensional gas chromatography coupled to mass spectrometry (GC×GC/MS). GC×GC/MS offers unparalleled chromatographic separation and peak capacity and has been used in recent years to resolve individual constituents within complex mixtures, including structural isomers. Since the biodegradation and toxicity of NAs is structure-specific and can vary between structural isomers, the profiling of individual NAs by GC×GC/MS is expected to enhance the monitoring of NAs within environmental samples impacted by oil sands activity. In this thesis, GC×GC coupled with time-of-flight mass spectrometry (TOFMS) was used to structurally elucidate a number of ‘unknown’ classical and sulfur-containing naphthenic acids by interpretation of their electron ionization (EI) mass spectra and, if available, confirmed by comparison with the spectra of references standards. GC×GC/TOFMS was also utilized as a fingerprinting tool to assess the temporal and spatial variability at two reclamation sites in the AOSR: Syncrude’s Sandhill Fen reclamation site and Base Mine Lake. Lastly, a methodology was developed which coupled GC×GC with a high resolution quadrupole time-of-flight mass spectrometer (QTOFMS) for the improved profiling of NAs. GC×GC/QTOFMS is advantageous for the monitoring of NAs since it can provide useful fingerprints via isomer distributions, differentiate NAs from several chemical classes, and provide a global overview of the elemental compositions (assigned by mass accuracy) within NA mixtures. / Thesis / Doctor of Philosophy (PhD)

Naphthenic acids (NAs) are carboxylated alkanes and cycloalkanes concentrated in wastewater during oil sands processing. The general chemical formula is C{n}H{n+Z}O{2}, where n represents the number of carbon atoms and Z specifies a homologous family with 0-6 rings (Z=0 to Z=-12). The wastewater is acutely toxic to surface water organisms and is stored in tailings ponds with over 230 million m?? of fines tailings and free water. The purpose of this thesis was to provide a preliminary evaluation of the potential attenuation of NAs during groundwater flow from the ponds. Laboratory studies were conducted to evaluate possible attenuation mechanisms. Aerobes from aquifer material degraded 60% of the NAs over 20 weeks in laboratory microcosms. The greatest decrease occurred in the low molecular weight bicyclic homologues with 12 to 16 carbons. The microbial activity confirms that aerobic naphthenate-degrading bacteria occur naturally in the glacial aquifer near Suncor's Pond 2/3. These results support the hypothesis that limited aerobic biodegradation of the smaller components of NAs could occur relatively rapidly under field conditions. There was no measurable decrease in NA concentration over six months in anaerobic microcosms, although microbial activity did lead to sulfate-reducing and methanogenic conditions. The theoretical retardation in glacio-fluvial sands was calculated using soil-water partitioning coefficients (K{d}) determined by batch equilibration experiments using a mixture of naturally occurring naphthenic acids as well as the nine surrogates. The retardation (porosity of 0. 3, bulk density of 1. 5 g/mL) ranged from 1. 2 to 2. 6. However, no measurable sorption was seen at the field sites. Detailed characterization allows us to examine how the proportions of homologue, or groups of molecules with the same molecular weight and number of cycloalkane rings, vary. Aerobic biodegradation favoured removal of low molecular weight NAs. A 15% mass loss attributed to sorption caused no changes in the 3D signature. Thus, changes in NA "signature" in groundwater systems were then attributed to aerobic biodegradation. Three plumes were examined for evidence of attenuation of NAs via biodegradation. First, the individual samples were classified as background, possibly process-affected or process-affected using a combination of Piper diagrams, the stable isotopes oxygen-18 and deuterium, dissolved chloride and sodium, as well as the total naphthenic acids concentration. Second, in order to estimate attenuation due to dispersive dilution, a linear correlation line was drawn between various conservative tracers and the naphthenic acids concentration. This allowed the identification of certain samples as possibly having a lower concentration of NAs than could be expected from simple dispersive dilution. Third, the 3D signature of certain samples were examined for the presence of the aerobic biodegradation 3D signature. One site showed good evidence for aerobic biodegradation of naphthenic acids. A second site showed some evidence for biodegradation under methanogenic conditions but the evidence was not definitive. The evidence at the third site was contradictory and no conclusions could be drawn from it. This research suggests some attenuation of NAs by biodegradation may be possible during groundwater flow.

Adequate wastewater management is a crucial element to achieve water sustainability in the petroleum refining sector, as their operations produce vast quantities of wastewater with potentially harmful contaminants. Treatment technologies are therefore pivotal for stopping these chemicals from entering the environment and protecting receiving environments. However, refining effluents are still linked to serious pollution problems, partly because little progress has been made in determining the causative agents of the observed biological effects, resulting in non-targeted treatment. Here it is shown that naphthenic acids, which have been reported as toxic and recalcitrant, are important components of refining wastewater resulting from the processing of heavy crude oil and that they have a significant contribution to the toxic effects exerted by these effluents. Furthermore, it was found that their chemical stability makes them highly resistant to remediation using Pseudomonas putida and H2O2/Fe-TAML (TetraAmido Macrocyclic Ligands) systems under laboratory conditions, and only sequential aliquots of Fe-TAML catalysts and H2O2 showed to partially degrade naphthenic acids (50 mg/L) within 72 hours. Results suggest that a combinatorial approach of Fe-TAML/H2O2 followed by biodegradation might improve current treatment options, but further optimisation is required for the biological treatment. These results can serve as a starting point for better environmental regulations relevant to oil refining wastewater resulting from heavy crude oil, as naphthenic acids are not currently considered in the effluent guidelines for the refining sector. Furthermore, the degradation of naphthenic acids under mild conditions using Fe-TAML/H2O2 systems indicates that these catalysts hold promise for the remediation of refining wastewater in real-life scenarios.