Examination of the swimming capabilities of fish is increasingly being considered as an effective method for determining sublethal toxicity. Acute toxicant exposure is known to cause decreases in swim performance in fish but less is known about how developmental exposure can cause persistent effects that hinder swimming. In addition, little is known about how triglyceride levels fluctuate during fish swimming upon both acute and developmental exposure to toxicant. In this thesis, two studies, one acute and one developmental, were carried out using two different toxicants in order to address these issues.<p> In order to examine acute effects, adult zebrafish (Danio rerio) were exposed to ethanol vehicle or increasing concentrations of 2,4-dinitrophenol (DNP), a mitochondrial electron transport chain uncoupler, for a 24 h period. Following exposure, fish were placed in a swim tunnel for critical swimming speed (Ucrit) determination and swim motion analysis. Whole body triglyceride levels were then determined. Ucrit was decreased in a concentration dependent manner in both the 6 mg/L and 12 mg/L DNP exposure groups, with 6 mg/L DNP being considered sublethal and 12 mg/L approaching the LC50. A decrease in tail beat frequency was observed and is likely the main cause for the decrease in Ucrit in the DNP exposure groups. Triglyceride levels were elevated in a concentration dependent manner in the DNP exposure groups. This increase in triglyceride stores may be due to a behavioral adaption limiting swimming capabilities or due to a direct toxic action of DNP on lipid catabolism.<p> The second study examined whether developmental 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure would cause persistent toxic effects. Zebrafish embryos were exposed to dimethyl sulfoxide control or increasing concentrations of TCDD between 2-4 days post fertilization (dpf). At 5 dpf, cytochrome P450 1A (CYP1A) activity was determined. Fish were raised to 90 dpf with mortalities and deformities being recorded at 5 dpf, 10 dpf, and 90 dpf. At 90 dpf, fish were placed in swim tunnel and Ucrit , swimming motion, and aerobic scope (oxygen consumption rate during exercise minus oxygen consumption rate during rest) were determined. Following swimming, some fish were used for whole body triglyceride analysis while others were used for histological examination. Ucrit was shown to be decreased in the two highest sublethal TCDD exposure groups (0.1 and 1 ng/L) but not in the lowest TCDD exposure group (0.01 ng/L). The exact cause of the decrease in Ucrit is not known, but may be linked to the observed decrease in dorsal aorta diameter, an inability to mobilize triglyceride stores, behavioral adaptations limiting swimming, decreased body length, or a combination of these factors. This TCDD related defect in swimming ability is not due to any increases in gross deformity or mortality rates, nor does it appear that CYP1A induction is required to mediate the toxic effects. Thus, it appears that examination of swim performance may serve as an effective measure of both sublethal acute and developmental toxicities.

The oil sands operations in northeast Alberta, Canada, employ unconventional processes to produce synthetic crude oil (SCO). Because the extracted bitumen, ¡®the form of oil in oil sands¡¯, is highly viscous, it requires thermal upgrading to produce SCO. Coking technology is used to convert heavy bitumen fractions to lighter volatile fractions. During this process, an enormous volume of solid coke is produced and the metal impurities (e.g. Al, Fe, Mn, Ni, Ti and V) present in bitumen fractions end-up in the coke particles. As coke demands significant space for storage, oil sands companies are exploring options for placing coke into reclamation landscapes for long term storage and recovery. However, coke holds appreciable amounts of potentially leachable metals that may impede the performance of reclamation landscapes. Although two previous coke leaching studies had showed that coke released metals into water at concentrations exceeding the Canadian guidelines for the protection of aquatic life, the ecotoxicological hazard and risk of these metals were not well characterized. Therefore, the overall goal of this research was to characterize the fate and toxicity of metals associated with coke. In this research, the toxicity of coke leachates collected from oil sands field sites and those artificially generated in the laboratory were evaluated using a standard three-brood Ceriodaphnia dubia tests. Coke leachates (CLs) collected over a period of 20 months from two field lysimeters were found to be acutely toxic to C. dubia. Vanadium concentrations were significantly higher (p¡Ü0.05) than concentrations of all other metals in CLs from both lysimeters, and also in leachates from a laboratory batch renewal leaching study. Furthermore, toxic unit (TU) calculations suggested that Ni and V were likely the cause of CL toxicity, but this was not explicitly proven. Therefore, a chronic toxicity identification and evaluation (TIE) approach was adopted to identify and confirm the cause(s) of CL toxicity. Coke was subjected to a 15 day batch leaching process in the laboratory at pH 5.5 and 9.5 in order to characterize the effect of pH on metals release from coke, and to generate CLs for use in TIE tests. The 7-day LC50 estimates for C. dubia survival were 6.3% and 28.7% (v/v) for CLs generated at pH 5.5 and 9.5, respectively. The dissolved concentrations of Mn, Ni and Zn were high (p¡Ü0.05) in pH 5.5 CL, whereas Al, Mo and V were high (p¡Ü0.05) in pH 9.5 CL. Evidence gathered from a series of chronic TIE tests revealed that Ni and V were the cause of toxicity in pH 5.5 CL, whereas V was the primary cause of toxicity in pH 9.5 CL. Further, the influence of bicarbonate, chloride and sulfate ions on metals release, speciation and Ni and V toxicity was investigated. The type and amount of metals released from coke was significantly influenced by the ion type elevated in the leaching solution. Specifically, sulfate influenced mobilization of Ni, Fe, Mn and Zn from coke, whereas bicarbonate enhanced Al, Mo and V releases from coke. With respect to toxicity, increasing bicarbonate decreased the 7-day Ni2+ IC50 from 6.3 to 2.3 ¦Ìg Ni2+/L suggesting enhanced Ni toxicity at high pH or alkalinity. Conversely, sulfate showed a protective effect against V toxicity to C. dubia. The research presented in this thesis suggests that coke will not be inert when stored in reclamation landscapes and that metals, particularly Ni and V, could reach ecotoxicologically relevant levels in surface waters or substrate porewaters, under favourable leaching conditions. Operationally, efforts should focus on remediation and monitoring of metals released from coke, particularly Ni and V, in impacted wetlands, especially before discharging water into natural wetlands and/or local streams and rivers.

SirT1 is a class III histone deacetylase that has beneficial roles in various diseases related to aging such as cancer, diabetes and neurodegenerative disease. Resveratrol is a natural compound that mimics most of the beneficial effects attributed to SirT1. Resveratrol has toxicity towards cancer cells and has been reported to be a direct activator of SirT1. Interestingly, SirT1 over-expression has also been reported to be toxic. We set out to determine if resveratrol toxicity is mediated through activation of SirT1. We have assessed resveratrol toxicity in embryonic stem cells and mouse embryonic fibroblast (MEFs) across different SirT1 genotypes. Our data indicates that SirT1 is not implicated in resveratrol toxicity in either normal or transformed MEFs. Thus, resveratrol toxicity does not appear to be mediated by SirT1.

There is increasing global recognition of the effects of large scale land disturbance by wildfire on a wide range of water and ecosystem services. In 2003, the Lost Creek wildfire burned a contiguous area of 21,000 ha on the eastern slopes of the Rocky Mountains in southern Alberta. This disturbance had a significant and prolonged impact on the water quantity and quality of downstream river reaches and reservoirs in the Oldman watershed. Previous research in this watershed demonstrates that dissolved metal concentrations in rivers draining burned landscapes were 2 to 15 times greater than in unburned reference streams (Silins et al. 2009a). Currently there is no information on the effects of wildfire on the bioaccumulation and toxicity of sediment-associated metals in fire-impacted streams in Alberta. This study was designed to evaluate the linear downstream disturbance effects of wildfire in the Crowsnest River located in southern Alberta. The toxicity and bioaccumulation of particulate-associated metals from wildfire impacted tributaries to the Crowsnest River on freshwater amphipod Hyalella azteca were evaluated. Phillips samplers were deployed to collect suspended solids in streams draining burned zone impacted by the Lost Creek wildfire and reference (unburned) zones within the area. Metal toxicity and bioaccumulation were determined in the laboratory by exposing the epi-benthic freshwater amphipod Hyalella azteca to particulates collected from the Crowsnest River. A metal effects addition model (MEAM) was used to assess the impact of metal mixtures and to predict chronic mortality (Norwood et al. 2013). Increased concentrations of Al, Ba, Co, Cr, Mn and Zn were found in the tissues of H. azteca exposed to particulates from burned watersheds in comparison to the unburned watersheds. H. azteca mean survival was similar when exposed to the particulates samples from both burned and unburned sites indicating that 9 years after this landscape disturbance, there was little impact due to the wildfire. However, at burned site (B1), the observed survival was lower than survival predicted by MEAM. The data suggests that factors other than the metals examined in this study were influencing the survival of H. azteca. The concentrations of sediment-associated metals have decreased in the nine years since the wildfire, and minimal metal toxicity was observed in H. azteca. Although metal toxicity in H. azteca was minimal 9 years after the Lost Creek Fire, the short term effects of wildfire on metal toxicity remain largely unknown. In addition, other factors such as burn severity, stream size and hydroclimatic conditions can influence the effects of wildfire on abundance and diversity of aquatic invertebrates (Minshall et al. 2001). Therefore, the influences of those factors on metal toxicity as a result of wildfire should be rigorously assessed in future studies.

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants known for their photoinduced toxicity. There are two mechanisms through which this may occur: photosensitization and photomodification. Photosensitization generally leads to the production of singlet oxygen, a reactive oxygen species (ROS), which is highly damaging to biological molecules. Photomodification of PAHs, usually via oxygenation, results in the formation of new compounds (oxyPAHs), and can occur under environmentally relevant levels of actinic radiation. <br /><br /> PAHs and oxyPAHs readily adsorb to the organic phase of particulate matter in the environment such as sediments. It is logical to conclude that sediment transport will also facilitate the transport of these contaminants, and it has been shown that in the course of transport, degradative processes evoke a change in the profile of the PAHs present. Sediment samples taken along a transect from Hamilton Harbour were fractionated, and analyzed using a 2D HPLC method. All sediments contained intact and modified PAHs, although a marked change was noted in the profile of compounds present in the samples, which differ in distance from shore. Fractions of sediment extract were tested for toxicity using a bacterial respiration assay. Toxicity was observed in fractions containing modified PAHs, and was similar to that of intact PAH-containing fractions. <br /><br /> Subsequently, the toxicities of 16 intact PAHs were assessed to <i>Daphnia magna</i> under two ultraviolet radiation (UV) conditions. The toxicity of intact PAHs generally increased in the presence of full spectrum simulated solar radiation (SSR), relative to visible light plus UVA only. To expand the existing data on the effects of PAH photoproducts to animals, fourteen oxyPAHs were also assayed with <i>D. magna</i>, most of which were highly toxic without further photomodification. The data presented highlight the effects of UV radiation on mediating PAH toxicity. The importance of the role of photomodification is also stressed, as several oxyPAHs were highly toxic to <i>D. magna</i>, a key bioindicator species in aquatic ecosystems. <br /><br /> A QSAR model previously developed for <i>Lemna gibba</i> showed that a photosensitization factor (PSF) and a photomodification factor (PMF) could be combined to describe toxicity. To determine whether it was predictive for <i>D. magna</i>, toxicity was assessed as both EC50 and ET50. As with <i>L. gibba</i> and <i>Vibrio fischeri</i>, neither the PSF nor the PMF alone correlated to D. magna toxicity. However, a PSF modified for <i>D. magna</i> did in fact exhibit correlation with toxicity, which was further improved when summed with a modified PMF. The greatest correlation was observed with EC50 toxicity data. This research provides further evidence that models that include factors for photosensitization and photomodification will likely be applicable across a broad range of species. To gain further knowledge of the roles that the variables contributing to the photosensitization and photomodification, a structural equation model was constructed based on the <i>D. magna</i> QSAR. This model accounted for a high amount of variance in six sets of toxicity data, as well as insight into the mechanisms of phototoxicity affecting different aquatic organisms.

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants known for their photoinduced toxicity. There are two mechanisms through which this may occur: photosensitization and photomodification. Photosensitization generally leads to the production of singlet oxygen, a reactive oxygen species (ROS), which is highly damaging to biological molecules. Photomodification of PAHs, usually via oxygenation, results in the formation of new compounds (oxyPAHs), and can occur under environmentally relevant levels of actinic radiation. <br /><br /> PAHs and oxyPAHs readily adsorb to the organic phase of particulate matter in the environment such as sediments. It is logical to conclude that sediment transport will also facilitate the transport of these contaminants, and it has been shown that in the course of transport, degradative processes evoke a change in the profile of the PAHs present. Sediment samples taken along a transect from Hamilton Harbour were fractionated, and analyzed using a 2D HPLC method. All sediments contained intact and modified PAHs, although a marked change was noted in the profile of compounds present in the samples, which differ in distance from shore. Fractions of sediment extract were tested for toxicity using a bacterial respiration assay. Toxicity was observed in fractions containing modified PAHs, and was similar to that of intact PAH-containing fractions. <br /><br /> Subsequently, the toxicities of 16 intact PAHs were assessed to <i>Daphnia magna</i> under two ultraviolet radiation (UV) conditions. The toxicity of intact PAHs generally increased in the presence of full spectrum simulated solar radiation (SSR), relative to visible light plus UVA only. To expand the existing data on the effects of PAH photoproducts to animals, fourteen oxyPAHs were also assayed with <i>D. magna</i>, most of which were highly toxic without further photomodification. The data presented highlight the effects of UV radiation on mediating PAH toxicity. The importance of the role of photomodification is also stressed, as several oxyPAHs were highly toxic to <i>D. magna</i>, a key bioindicator species in aquatic ecosystems. <br /><br /> A QSAR model previously developed for <i>Lemna gibba</i> showed that a photosensitization factor (PSF) and a photomodification factor (PMF) could be combined to describe toxicity. To determine whether it was predictive for <i>D. magna</i>, toxicity was assessed as both EC50 and ET50. As with <i>L. gibba</i> and <i>Vibrio fischeri</i>, neither the PSF nor the PMF alone correlated to D. magna toxicity. However, a PSF modified for <i>D. magna</i> did in fact exhibit correlation with toxicity, which was further improved when summed with a modified PMF. The greatest correlation was observed with EC50 toxicity data. This research provides further evidence that models that include factors for photosensitization and photomodification will likely be applicable across a broad range of species. To gain further knowledge of the roles that the variables contributing to the photosensitization and photomodification, a structural equation model was constructed based on the <i>D. magna</i> QSAR. This model accounted for a high amount of variance in six sets of toxicity data, as well as insight into the mechanisms of phototoxicity affecting different aquatic organisms.

Examination of the swimming capabilities of fish is increasingly being considered as an effective method for determining sublethal toxicity. Acute toxicant exposure is known to cause decreases in swim performance in fish but less is known about how developmental exposure can cause persistent effects that hinder swimming. In addition, little is known about how triglyceride levels fluctuate during fish swimming upon both acute and developmental exposure to toxicant. In this thesis, two studies, one acute and one developmental, were carried out using two different toxicants in order to address these issues.<p> In order to examine acute effects, adult zebrafish (Danio rerio) were exposed to ethanol vehicle or increasing concentrations of 2,4-dinitrophenol (DNP), a mitochondrial electron transport chain uncoupler, for a 24 h period. Following exposure, fish were placed in a swim tunnel for critical swimming speed (Ucrit) determination and swim motion analysis. Whole body triglyceride levels were then determined. Ucrit was decreased in a concentration dependent manner in both the 6 mg/L and 12 mg/L DNP exposure groups, with 6 mg/L DNP being considered sublethal and 12 mg/L approaching the LC50. A decrease in tail beat frequency was observed and is likely the main cause for the decrease in Ucrit in the DNP exposure groups. Triglyceride levels were elevated in a concentration dependent manner in the DNP exposure groups. This increase in triglyceride stores may be due to a behavioral adaption limiting swimming capabilities or due to a direct toxic action of DNP on lipid catabolism.<p> The second study examined whether developmental 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure would cause persistent toxic effects. Zebrafish embryos were exposed to dimethyl sulfoxide control or increasing concentrations of TCDD between 2-4 days post fertilization (dpf). At 5 dpf, cytochrome P450 1A (CYP1A) activity was determined. Fish were raised to 90 dpf with mortalities and deformities being recorded at 5 dpf, 10 dpf, and 90 dpf. At 90 dpf, fish were placed in swim tunnel and Ucrit , swimming motion, and aerobic scope (oxygen consumption rate during exercise minus oxygen consumption rate during rest) were determined. Following swimming, some fish were used for whole body triglyceride analysis while others were used for histological examination. Ucrit was shown to be decreased in the two highest sublethal TCDD exposure groups (0.1 and 1 ng/L) but not in the lowest TCDD exposure group (0.01 ng/L). The exact cause of the decrease in Ucrit is not known, but may be linked to the observed decrease in dorsal aorta diameter, an inability to mobilize triglyceride stores, behavioral adaptations limiting swimming, decreased body length, or a combination of these factors. This TCDD related defect in swimming ability is not due to any increases in gross deformity or mortality rates, nor does it appear that CYP1A induction is required to mediate the toxic effects. Thus, it appears that examination of swim performance may serve as an effective measure of both sublethal acute and developmental toxicities.

PDMS has not only the characteristics of good chemical and physical properties,flexible, low surface free energy, and good optically transparent, also has the advantages of low cost, low toxicity and environmental protection. In this study we use PDMS to fabricate liquid crystal device with different micro-confined structures. We had a discussion about liquid crystal in the micro-confined structure through optical textures and measured electro-optical characteristics on our device. Through the experiment we found the liquid crystal device with micro-confined structure had not only the characteristics of wide viewing angle and contrast ratio has been up to standard in normal display. And it also demonstrated the capability in flexible liquid crystal display.

In this study, a reproducible spectrophotometric method was established and applied to measure reductive capacity of various nanomaterials. Reductive capacity had been implicated in the toxicity of nanomaterials, but a standardized measurement method had been lacking until this work. The reductive capacity of nanoparticles was defined as the mass of iron reduced from Fe3 to Fe2 by unit mass of nanoparticles, in an aqueous solution that initially contained ferric ions. To measure the reductive capacity, the nanomaterials were incubated in a ferric aqueous solution for 16 hours at 37 degrees C, and the reductive capacity of the nanoparticles was determined by measuring the amount of Fe3 reduced to Fe2 using a spectrophotometric method. The reagents 1,10-phenanthroline and hydroquinone were used as a Fe2 indicator and a reducing agent respectively for the assay. To standardize this method, various experiments were carried out. For the initial ferric solution, various Fe salts were tested, and Iron(III) sulfate was chosen as Fe salt for the standard method. The measured reductive capacity of nanoparticles was found to vary with the measurement conditions; the measured reductive capacity increased with increasing the Fe/nanoparticle ratio; the measured reductive capacity increased with incubation time and leveled off after 8 hours of incubation. For hydrophobic materials, the surfactant Tween-20 was added so that the particles could be wetted and suspended in the ferric aqueous solution. After incubation, the particles were removed from the solution by either filtration or centrifugation before applying the spectrophotometric method. In addition, optimal pH and minimum time to reach ultimate color intensity were also found. Carbon-based nanomaterials, standard reference material and metal oxides were measured for their reductive capacities with this method and characterized by transmission electron microscopy (TEM), energy dispersive x-ray spectroscopy (EDS), x-ray diffraction (XRD), BET measurement and Raman spectroscopy. For some nanoparticles, the reductive capacity was measured for both the pristine form and the form treated by oxidization or grinding. All carbon-based nanomaterials, except for pristine C60, have a significant reductive capacity while reductive capacity of metal oxides is very low. And it was found that reductive capacity can be increased by surface functional groups or structural defects and reduced by oxidization or heating (graphitization). The reductive capacity of a material can play an important role in its toxicology by synergistic toxic effects in the presence of transition metal ions through the Fenton reaction. Moreover, even without transition metal ions, the ability of a material to donate electrons can be involved in toxicity mechanisms via generation of reactive oxygen species.

The ecological effects and mechanistic efficiency of chemical oil spill countermeasures must be evaluated prior to their ethical application during real spill response scenarios. Equally important is the ability to monitor the effectiveness of any spill response in real time, permitting informed response management. In-situ sensors are key components of such event based monitoring and continuous monitoring programs. This project investigates crude oil toxicity as a particulate suspension, suitability of in-situ instrumentation to measure crude oil suspensions, and the applicability of using acoustic backscatter to measure suspended solids and sub-surface oil droplet suspension concentrations. The ecological effects to inter- and sub-tidal sediment dwelling organisms exposed to crude oil, both treated with a chemical dispersant and un-treated, was evaluated. Elevated toxicity, expressed as percent mortality and reduced luminescence, and oil concentrations were observed in inter-tidal sediments receiving oil only treatments compared to oil-plus-dispersant treatments. Sub-tidal sediments showed heterogeneous distribution of crude oil with elevated amphipod mortality compared to no oil controls suggesting an oil-sediment aggregation mechanism. A separate laboratory scale study found that the soluble crude oil fractions were responsible for the observed mortality in pelagic species while the more dominant oil droplet fractions were relatively non-toxic. Subsequent studies focused on the in-situ detection of crude oil and particle suspensions in aqueous environments. The first showed that both in-situ fluorescence spectroscopy and Laser In-Situ Scattering Transmissometry (LISST) can effectively measure crude oil concentrations in aqueous environments. The applicability of the LISST implies that crude oil in an aqueous medium can be measured as a particle suspension. Acoustic backscatter (ABS) was investigated for its applicability as a surrogate measurement technology for aqueous particle suspensions. This study showed a log linear correlation between ABS and volume concentration (VC) over a variable particle size distribution. This correlation is due to the dependency of both ABS and VC to the particle size distribution. Log-linear ABS responses to oil-droplet suspension volume concentrations were also demonstrated. However, the inability to reproduce response factors suggests that more work is required to produce viable calibrations that may be used for sub-surface oil plume detection.