Understanding the processes of oilsands process-affected water phytoremediation using native plant species
Date
2022-11-28
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Abstract
Bitumen mining in the oil sands region in Alberta, Canada, generates large volumes of oil sands process-affected water (OSPW). Naphthenic acid fraction compounds (NAFCs) are a major contributor to OSPW toxicity and are a target for removal using remediation approaches. Phytoremediation, the use of plants to remediate the environment, is a biotechnology that has commercial potential as a large-scale treatment strategy for OSPW. Although studies performed thus far demonstrate that phytoremediation is a feasible approach, the mechanisms involved in this process are not well understood. This thesis aims to understand how upland plants can attenuate or modify NAFCs in OSPW and gain insight into the physiological and molecular events that occur when NAFCs are taken up into plant tissue. Lab-scaled hydroponic and soil experiments, greenhouse sub-surface flow mesocosm experiments, and plant NA-tolerance analysis were performed using isotopic NA and NAFC compounds. Plants were shown to take up isotopically-labelled NAs into the root and shoot tissue and localize NA-derived carbon in newly growing tissues. NAFC uptake was observed and was enhanced when plants were grown in media adjusted to lower pH levels naturally found in the rhizosphere. The presence of plants in mesocosm systems resulted in greater decreases in classical O2 NAFC concentrations than in no-plant mesocosms and overall decreases in total NAFC concentrations were observed within 7 days. Additionally, toxicity was reduced after OSPW treatment in plant and no-plant mesocosms. Mass balance analysis revealed that most of the NA-derived carbon taken up by plants remains within the root and shoot tissue, but a small amount was captured in headspace traps, suggesting that limited phytovolatilization processes are involved in plant NA metabolism. Finally, selected NA-tolerant plants displayed NA-derived carbon localization in the vasculature of leaves but no overall difference in the uptake of NAs compared to wildtype plants. The results of this research support the use of phytoremediation using upland plants as a viable approach to OSPW treatment and are foundational for future studies on NAFC metabolism in plants.
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Keywords
Phytoremediation, Toxicology, Willow, Wheatgrass, Arabidopsis, Mesocosms, Oil sands
Citation
Alberts, M. E. (2022). Understanding the processes of oilsands process-affected water phytoremediation using native plant species (Doctoral thesis). University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca .