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Spatial variations of total and dissolved trace elements and their distributions amongst major colloidal forms along and across the Lower Athabasca River
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- Author / Creator
- Ghotbizadeh, Marjan
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The Athabasca River (AR) is the longest river in Alberta with a wide variety of natural and potential anthropogenic inputs. The purpose of this study was to quantify the spatial variation of trace element (TE) concentrations and forms in this aquatic system. Water samples were gathered along a 125-km stretch of the river and at three points across the river, in locations upstream, alongside and downstream from the industrial region. The samples were collected using the novel, metal-free sampling methods. With respect to water quality and the uptake/toxicity of trace elements, and to determine the biological significance of trace elements in the river, their size-based distribution amongst different colloidal forms (i.e. truly dissolved, primarily organic, and primarily inorganic) was measured in the dissolved fraction (i.e., < 0.45 µm by filtration). In addition, total concentrations of trace elements were normalized to that of thorium (Th) to determine the extent of enrichment relative to natural ratios in the earth’s crust.Differences in the concentrations of dissolved and total TEs were observed between the transects upstream, midstream, and downstream of industry, and on the east and west sides of the river. Total concentrations of Al, As, Co, Cu, Fe, Mn, Ni, Pb, Th, Tl, and V were significantly (p < 0.05) more abundant downstream of industry, compared to upstream. With the exception of As and Cu, these elements occurred predominantly in the particulate fraction (i.e. > 0.45 µm). Normalization to Th showed that no trace elements were enriched in the particulate fraction. In the dissolved fraction (< 0.45 µm), concentrations of As, Co, Cu, Ni, Pb, Re, and V were significantly (p < 0.05) more abundant downstream of industry. Within the dissolved fraction, Fe and Pb were found mainly as primarily inorganic colloids, while the other trace elements occurred predominantly in the mainly ionic/truly dissolved fraction (i.e., < ca. 1 kDa). The average concentrations of the investigated trace elements were far below the surface water quality guidelines in the Athabasca River. The PCA analysis indicated that tributaries contribute meaningful amounts of total and dissolved trace elements to the AR.
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- Graduation date
- Fall 2020
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- Type of Item
- Thesis
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- Degree
- Master of Science
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- License
- Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.