Developments in Molecular Level Characterization of Naphthenic Acid Fraction Compounds Degradation in a Constructed Wetland Treatment System

The reclamation of oil sands process-affected water (OSPW) is a matter of environmental importance because of the aquatic toxicity to biota. This study describes refinements in advanced analytical methods to assess the performance of biological treatment systems for OSPW, such as constructed wetland treatment systems (CWTSs). Assessment of treatment efficiency by measurement of the degradation of naphthenic acid fraction compounds (NAFCs) in OSPW is challenging in CWTS due to potentially interfering constituents such as humic acids, organic acids, salts, and hydrocarbons. Here we have applied a previous weak anion exchange (WAX) solid-phase extraction (SPE) method and high-resolution Orbitrap-mass spectrometry (MS) to remove major interferences from the NAFC analysis. The refinements in data processing employing principal component analysis (PCA) indicates that the relative abundance of NAFCs decreased with time in the treated OSPW relative to the untreated OSPW. The most saturated NAFCs with higher carbon numbers were relatively more degraded as compared to unsaturated NAFCs. The use of Kendrick plots and van Krevelen plots for assessment of the performance of the CWTS is shown to be well-suited to detailed monitoring of the complex composition of NAFCs as a function of degradation. The developments and application of analytical methods such as the WAX SPE method and high-resolution Orbitrap-MS are demonstrated as tools enabling the advancement of CWTS design and optimization, enabling passive or semi-passive water treatment systems to be a viable opportunity for OSPW treatment.

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Characterization of naphthenic acid fraction compounds in water from Athabasca oil sands wetlands by Orbitrap high-resolution mass spectrometry

The Science of The Total Environment ◽

10.1016/j.scitotenv.2021.146342 ◽

2021 ◽

pp. 146342

Author(s):

Ian J. Vander Meulen ◽

Danna M. Schock ◽

Joanne L. Parrott ◽

Lukas J. Mundy ◽

Bruce D. Pauli ◽

...

Keyword(s):

Mass Spectrometry ◽

High Resolution ◽

Oil Sands ◽

High Resolution Mass Spectrometry ◽

Naphthenic Acid ◽

Acid Fraction ◽

Athabasca Oil Sands ◽

High Resolution Mass ◽

Resolution Mass

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Investigating the toxicity of naphthenic acid fraction components from oil sands process-affected water to developing fathead minnow (Pimephales promelas)

Inquiry@Queen's Undergraduate Research Conference Proceedings ◽

10.24908/iqurcp.14026 ◽

2020 ◽

Author(s):

Brianna Jackson

Keyword(s):

Oil Sands ◽

Fathead Minnow ◽

Pimephales Promelas ◽

Naphthenic Acid ◽

Natural Setting ◽

Acid Fraction ◽

Spinal Curvatures ◽

Aquatic Life ◽

Pericardial Edema ◽

Embryo Heart

The extraction of bitumen from Alberta’s oil sands region generates large volumes of oil sands process-affected water (OSPW) that is stored in tailings ponds. Toxic constituents present in OSPW such as naphthenic acid fraction components (NAFCs) can cause adverse effects to aquatic life. Recent research has focused on the toxicity of NAFCs to highly vulnerable early life stages of fish. Here we examined the embryotoxicity of NAFCs (0-54 mg/L) extracted from OSPW to native fathead minnow (Pimephales promelas) from 1-day post-fertilization to hatch in a semi-natural setting at Queen’s University’s Biological Station. Embryo heart rate, mortality, prevalence and severity of malformations at hatch, post-hatch mass, and basal activity at hatch was examined. Embryo heart rates declined with increasing NAFC concentration, preceding pronounced exposure-response patterns of mortality and non-viable hatches. Visible malformations included cardiovascular (pericardial edema; present in 81.51% of non-viable hatches), craniofacial (reduced jaw and head size; 68.96%), myoskeletal (spinal curvatures; 60.90%), and peritoneal (yolk sac edema; 26.44%) malformations, that significantly increased in severity with increasing NAFC concentration. Fish that survived lethal concentrations displayed evidence of nervous system impairment including elevated patterns of erratic twitching. Post-hatch mass generally increased with increasing NAFC exposure, potentially as a compensatory-like response. Results of this work are the first to be reported in a semi-natural exposure setting and provide important toxicological information that will aid future policy directives for the management of OSPW in Alberta, Canada.

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Transcriptome Analysis of Environmental Pseudomonas Isolates Reveals Mechanisms of Biodegradation of Naphthenic Acid Fraction Compounds (NAFCs) in Oil Sands Tailings

Microorganisms ◽

10.3390/microorganisms9102124 ◽

2021 ◽

Vol 9 (10) ◽

pp. 2124

Author(s):

Parisa Chegounian ◽

Stephane Flibotte ◽

Kerry Peru ◽

John Headley ◽

Dena McMartin ◽

...

Keyword(s):

Oil Sands ◽

Naphthenic Acid ◽

Gene Products ◽

Acid Fraction ◽

Microbial Cultures ◽

New Directions ◽

Pure Cultures ◽

Biochemical Mechanisms ◽

Oil Sands Tailings ◽

Shed Light

Naphthenic acid fraction compounds (NAFCs) are highly recalcitrant constituents of oil sands tailings. Although some microorganisms in the tailings can individually and synergistically metabolize NAFCs, the biochemical mechanisms that underpin these processes are hitherto unknown. To this end, we isolated two microorganisms, Pseudomonas protegens and Pseudomonas putida, from oils sands tailings and analyzed their transcriptomes to shed light on the metabolic processes employed by them to degrade and detoxify NAFCs. We identified 1048, 521 and 1434 genes that are upregulated in P. protegens, P. putida and a 1:1 co-culture of the strains, respectively. We subsequently enumerated the biochemical activities of enriched genes and gene products to reveal the identities of the enzymes that are associated with NAFC degradation. Separately, we analyzed the NAFCs that are degraded by the two pseudomonads and their 1:1 co-culture and determined the composition of the molecules using mass spectrometry. We then compared these molecular formulas to those of the cognate substrates of the enriched enzymes to chart the metabolic network and understand the mechanisms of degradation that are employed by the microbial cultures. Not only does the consortium behave differently than the pure cultures, but our analysis also revealed the mechanisms responsible for accelerated rate of degradation of NAFCs by the co-culture. Our findings provide new directions for engineering or evolving microorganisms and their consortia for degrading NAFCs more stably and aggressively.

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