Research

Esteban Gillio Meina

Vanadium, present in the bitumen from the Oil Sands region (Alberta), becomes enriched in the coke, during the upgrading process. New reclamation techniques proposed the use of coke to remediate oil sand process water (OSPW). However, when coke is incorporated into the OSPW, vanadium concentrations rapidly increased from negligible to potential toxic for aquatic organisms. Previous studies showed that vanadium is toxic to aquatic organisms, but there is little information on how water characteristics modify this toxicity. Therefore, my research is focused on the development of models to better understand how environmental modifying factors representative of OSPW and Athabasca River modify vanadium’s toxicity to regional aquatic organisms. Moreover, the mechanism of action of vanadium will be elucidated to better interpret its toxicity. This project will contribute to develop site specific guidelines applicable to the Oil Sand region (Alberta) and other regions of Canada, improve risk assessment and even land reclamation.

Larry D'Silva

Mobilization of sediment-bound phosphorus and arsenic in a prairie reservoir. Buffalo Pound Lake, Saskatchewan, Canada, supplies drinking water to the major cities of Regina and Moose Jaw. Annual summer algal blooms develop in this reservoir creating drinking water treatment challenges. My research will investigate the potential for nutrient, specifically phosphorous, remobilization from lake sediments, which can stimulate these blooms. This study will focus on mobilization of phosphorus, as well as the toxic element arsenic, which can both be released from sediments with such releases varying seasonally. This study will also include a paleogeochemical aspect to document concentrations of different phosphorus forms (species) within the vertical sediment profile (i.e. investigate changes in phosphorus deposition over time). The results from this project will help improve our understanding of internal nutrient loading in Buffalo Pound Lake, and hopefully inform prairie lake and reservoir management practices on a broader scale. 

Sarah Crawford

My research focuses on quantifying and modeling sediment physicochemical factors that influence the bioavailability, and hence toxicity, of sediment-associated uranium to a model freshwater benthic invertebrate (Chironomus dilutus).  Results from this work will help improve risk assessments, environmental regulations and management of uranium concentrations downstream of uranium operations in northern Saskatchewan.

Stephanie Schiffer

Vanadium toxicity to aquatic organisms’ representative of the Athabasca Oil Sands region.  This project will evaluate the acute and chronic toxicity of aqueous vanadium on survival, growth, and reproduction of model freshwater test species from four major taxa (algal, planktonic and benthic invertebrates, and fish) and an equal number of field relevant species representative of the Athabasca Oil Sands region. From these and other published data, acute and chronic species sensitivity distributions will be developed for vanadium, and the sensitivities of standard laboratory species compared to those of field relevant species. Results from this research will help assess the ecological risk vanadium found in coke leachates may pose to various receiving environments in the Athabasca Oil Sands region.

Past Research

Brett Lucas
My research attempts to reconstruct the historical nutrient status trends within Lake Diefenbaker, a multi-purpose reservoir in Saskatchewan, and to identify whether or not these trends suggest decreasing water quality. Sediment core samples have been collected from deep-water sites within the reservoir and are currently being analyzed for temporal trends in various physicochemical variables and subfossil remains. Changes to community composition for both diatoms and chironomids (non-biting midges), based on subfossil remains and supported by various physcochemical data, are being used to infer temporal changes in environmental quality. In addition, stable isotope analyses (carbon, nitrogen and sulphur) are being used to identify the major nutrient source contributors to the reservoir (e.g., sources related to agriculture, aquaculture or municipal discharge).