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Trepanier KE, Vander Meulen IJ, Ahad JME, Headley JV, Degenhardt D. Evaluating the attenuation of naphthenic acids in constructed wetland mesocosms planted with Carex aquatilis. Environ Monit Assess 2023; 195:1228. [PMID: 37725196 PMCID: PMC10509100 DOI: 10.1007/s10661-023-11776-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 08/24/2023] [Indexed: 09/21/2023]
Abstract
Surface oil sands mining and extraction in northern Alberta's Athabasca oil sands region produce large volumes of oil sands process-affected water (OSPW). OSPW is a complex mixture containing major contaminant classes including trace metals, polycyclic aromatic hydrocarbons, and naphthenic acid fraction compounds (NAFCs). Naphthenic acids (NAs) are the primary organic toxicants in OSPW, and reducing their concentrations is a priority for oil sands companies. Previous evidence has shown that constructed wetland treatment systems (CWTSs) are capable of reducing the concentration of NAs and the toxicity of OSPW through bioremediation. In this study, we constructed greenhouse mesocosms with OSPW or lab process water (LPW) (i.e., water designed to mimic OSPW minus the NAFC content) with three treatments: (1) OSPW planted with Carex aquatilis; (2) OSPW, no plants; and (3) LPW, no plants. The OSPW-C. aquatilis treatment saw a significant reduction in NAFC concentrations in comparison to OSPW, no plant treatments, but both changed the distribution of the NAFCs in similar ways. Upon completion of the study, treatments with OSPW saw fewer high-molecular-weight NAs and an increase in the abundance of O3- and O4-containing formulae. Results from this study provide invaluable information on how constructed wetlands can be used in future remediation of OSPW in a way that previous studies were unable to achieve due to uncontrollable environmental factors in field experiments and the active, high-energy processes used in CWTSs pilot studies.
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Affiliation(s)
- Kaitlyn E Trepanier
- Canadian Forest Service, Northern Forestry Centre, Natural Resources Canada, Edmonton, AB, Canada
| | - Ian J Vander Meulen
- Environment and Climate Change Canada, National Hydrology Research Centre, Saskatoon, SK, Canada
- Department of Civil, Geological and Environmental Engineering, College of Engineering, University of Saskatchewan, Saskatoon, SK, Canada
| | - Jason M E Ahad
- Geological Survey of Canada, Natural Resources Canada, Québec, QC, Canada
| | - John V Headley
- Environment and Climate Change Canada, National Hydrology Research Centre, Saskatoon, SK, Canada
| | - Dani Degenhardt
- Canadian Forest Service, Northern Forestry Centre, Natural Resources Canada, Edmonton, AB, Canada.
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Yang Z, Zhang G, Hollebone BP, Brown CE, Yang C, Lambert P, Wang Z, Landriault M, Shah K. Fate of oxygenated intermediates in solar irradiated diluted bitumen mixed with saltwater. Environ Pollut 2017; 231:622-634. [PMID: 28843901 DOI: 10.1016/j.envpol.2017.08.043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 08/04/2017] [Accepted: 08/11/2017] [Indexed: 06/07/2023]
Abstract
Two types of diluted bitumen (dilbit) and a light crude oil spiked onto the surface of saltwater were irradiated with natural solar light in Ottawa to assess the impact of sunlight to the fate of oxygenated intermediates. Oxygenated components, including carbonyl polycyclic aromatic hydrocarbons (PAHs) and acidic polar fractions (naphthenic acid fraction compounds, NAFCs), were identified after periods of solar exposure under both winter and summer conditions. Carbonyl PAHs and NAFCs were formed in both seasons; however, light crude and summer irradiation produced higher abundance of them than dilbits and winter exposure. The formed NAFCs were abundant with the congeners containing a heteroatom of oxygen only (Oo species), accompanied by the minor amounts of sulfur- and nitrogen-containing acids. The produced Oo species were predominant with the congeners with light molecular weight, high degree of saturation and heavy oxygen numbers. For both carbonyl PAHs and NAFCs, their abundance continually increased throughout the period of winter exposure. In the summer, some carbonyl PAHs and all Oo species increased during the early exposure period; then they decreased with continued exposure for most oils, illustrating their transitional nature. Oxygenated intermediates thus appear to have been created through the photo-oxidation of non-to medium-polar petroleum hydrocarbons or the intermediates of aldehydes or ketones (O1). Oil properties, the duration of exposure, exposure season and the chemical structure of these intermediates are critical factors controlling their fate through photo-oxidation. The observed chemical changes highlight the effects of sunlight on the potential behavior, fate and impact of spilled oil, with the creation of new resin group compounds and the reduction of aromatics and saturates. These results also imply that the ecological effects of spilled oil, after ageing in sunlight, depend on the specific oil involved and the environmental conditions.
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Affiliation(s)
- Zeyu Yang
- Emergencies Science and Technology Section, Science and Technology Branch, Environment and Climate Change Canada, Ottawa, ON, K1A0H3, Canada.
| | - Gong Zhang
- Emergencies Science and Technology Section, Science and Technology Branch, Environment and Climate Change Canada, Ottawa, ON, K1A0H3, Canada
| | - Bruce P Hollebone
- Emergencies Science and Technology Section, Science and Technology Branch, Environment and Climate Change Canada, Ottawa, ON, K1A0H3, Canada
| | - Carl E Brown
- Emergencies Science and Technology Section, Science and Technology Branch, Environment and Climate Change Canada, Ottawa, ON, K1A0H3, Canada
| | - Chun Yang
- Emergencies Science and Technology Section, Science and Technology Branch, Environment and Climate Change Canada, Ottawa, ON, K1A0H3, Canada
| | - Patrick Lambert
- Emergencies Science and Technology Section, Science and Technology Branch, Environment and Climate Change Canada, Ottawa, ON, K1A0H3, Canada
| | - Zhendi Wang
- Emergencies Science and Technology Section, Science and Technology Branch, Environment and Climate Change Canada, Ottawa, ON, K1A0H3, Canada
| | - Mike Landriault
- Emergencies Science and Technology Section, Science and Technology Branch, Environment and Climate Change Canada, Ottawa, ON, K1A0H3, Canada
| | - Keval Shah
- Emergencies Science and Technology Section, Science and Technology Branch, Environment and Climate Change Canada, Ottawa, ON, K1A0H3, Canada
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