http://hdl.handle.net/1974/1851 2013-05-24T17:06:23Z 2013-05-24T17:06:23Z Gibson, Laura A Lavoie, Raphael A Campbell, Linda M Langlois, Valerie S http://hdl.handle.net/1974/8023 2013-05-07T05:15:34Z 2013-05-06T04:00:00Z

Title: Relationships Between Blood Mercury Concentrations and Oxidative Stress in Phalacrocorax auritus Authors: Gibson, Laura A; Lavoie, Raphael A; Campbell, Linda M; Langlois, Valerie S Abstract: Mercury (Hg) is a widespread contaminant that has been shown to induce adverse health effects in a wide range of organisms. We explored the relationship between total blood Hg concentrations ([Hg]) and oxidative stress induction in double-crested cormorants (Phalacrocorax auritus). Cormorant blood was sampled at five sites across the Great Lakes basin, Ontario, Canada and was analyzed for total [Hg].To assess cellular stress, the expression of glutathione peroxidases 1 and 3, glutathione S- transferase µ3, superoxide dismutase 1 and heat-shock protein 70 kd-8 were measured in whole blood samples. No significant variations in mean relative gene expression were found between sites for any gene for all birds. Linear regression analyses showed a slight, significantly positive relationship between individual blood [Hg] and gpx3 expression for all birds. However, when separated by sex, there were differences. Male cormorants displayed higher blood Hg concentrations than females. Female individuals showed significant positive relationships between blood Hg concentration and expression of glutathione peroxidase 3 and glutathione S-transferase μ3. Different levels of oxidative stress experienced by males and females during the breeding season may be influencing the differential oxidative stress responses to blood [Hg] observed in this study. Overall, the results of our study suggest that Hg leads to oxidative stress in the blood of P. auritus and that this oxidative stress is mediated by upregulation of gstm3 and gpx3 expression.

2013-05-06T04:00:00Z King, Meagan http://hdl.handle.net/1974/8002 2013-05-02T04:58:32Z 2013-05-01T04:00:00Z

Title: Assessing the probability and impact of secondary invasions of Hemimysis anomala to inland lakes of Ontario Authors: King, Meagan

2013-05-01T04:00:00Z Miller, Clare http://hdl.handle.net/1974/7944 2013-04-25T21:51:34Z 2013-04-25T04:00:00Z

Title: Removal of Arsenic Trioxide from a Simulated Human Gastrointestinal System through Adsorption onto Fe – oxides. Authors: Miller, Clare

2013-04-25T04:00:00Z Fenwick, Lindsay http://hdl.handle.net/1974/7943 2013-04-28T05:21:26Z 2013-04-25T04:00:00Z

Title: Characterization of Colloids in Circumneutral Mine Waters Resulting from Pb-Zn Tailings Authors: Fenwick, Lindsay Abstract: Natural waters are typically filtered to 0.45 microns in order to discriminate between truly dissolved and non-aqueous phases. Acid is then added to the sample as a preservative, and all measured concentrations are considered dissolved. However, it is well-known that the <0.45 μm fraction contains a mixture of truly dissolved ions, colloids, and particulate matter. Drainage samples from tailings depositories at the New Calumet Mine in Quebec, Canada were collected and subsequently ultra-filtered to 0.01 μm, capturing all particles between 0.01 μm and 0.45 μm in size. SEM analysis of the filter membranes revealed 100-300 nm spherical iron oxyhydroxides, zinc carbonates and/or oxyhydroxides, and adsorbed Zn on Fe-oxyhydroxides. Zn was also identified on biogenic particles. Fe was found to be carried predominantly in colloidal form, while only a small fraction of the Zn was found to be transported this way. The majority of the Zn was found to be dissolved, and bioavailable. It is important to understand the fraction of metal carried in colloidal form as colloids play an integral role in the fate and mobility of trace contaminants. Failure to account for colloidal particles may cause the bioavailability of trace metals to be over- or under- estimated. This has important implications for mine permitting and environmental assessments.

2013-04-25T04:00:00Z