The isotopic composition of carbon in the Alberta oil sand

Jha, K.N.; Gray, John Edward; Strausz, O. P.

doi:10.1016/0016-7037(79)90150-9

Cited by 8 publications

(5 citation statements)

References 13 publications

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“…The 1.0 to 1.5‰ δ 13 C depletion from the pre-1980s to post-1980s periods moved in the direction of the δ 13 C value (−30.1 ± 0.2‰, n = 7) determined by EA-IRMS for the aromatic fraction containing PAHs extracted from AOS (Figure ), which is similar to that previously determined for the AOS aromatic fraction (−30.4 ± 0.3‰) and bulk bitumen (−30.1 ± 0.4‰) . We assume the δ 13 C of the AOS aromatic fraction to be a good approximation of the δ 13 C signature of AOS-derived C1–F and DBT considering that the high molecular weight (HMW) fractions of AOS have similar δ 13 C values − and that the microbial maturation of bitumen is not expected to fractionate the δ 13 C of these HMW fractions . In contrast to the other two PAHs reported here, the δ 13 C signature of retene showed no discernible differences ( p -value retene = 0.29; Text S3, Supporting Information) between the top and the bottom of the core.…”

Section: Resultssupporting

confidence: 85%

Century-Long Source Apportionment of PAHs in Athabasca Oil Sands Region Lakes Using Diagnostic Ratios and Compound-Specific Carbon Isotope Signatures

Jautzy

Ahad

Gobeil

et al. 2013

Environ. Sci. Technol.

105

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Evaluating the impact that airborne contamination associated with Athabasca oil sands (AOS) mining operations has on the surrounding boreal forest ecosystem requires a rigorous approach to source discrimination. This study presents a century-long historical record of source apportionment of polycyclic aromatic hydrocarbons (PAHs) in dated sediments from two headwater lakes located approximately 40 and 55 km east from the main area of open pit mining activities. Concentrations of the 16 Environmental Protection Agency (EPA) priority PAHs in addition to retene, dibenzothiophene (DBT), and six alkylated groups were measured, and both PAH molecular diagnostic ratios and carbon isotopic signatures (δ(13)C) of individual PAHs were used to differentiate natural from anthropogenic inputs. Although concentrations of PAHs in these lakes were low and below the Canadian Council of Ministers of the Environment (CCME) guidelines, diagnostic ratios pointed to an increasingly larger input of petroleum-derived (i.e., petrogenic) PAHs over the past 30 years concomitant with δ(13)C values progressively shifting to the value of unprocessed AOS bitumen. This petrogenic source is attributed to the deposition of bitumen in dust particles associated with wind erosion from open pit mines.

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Section: Resultssupporting

confidence: 85%

Century-Long Source Apportionment of PAHs in Athabasca Oil Sands Region Lakes Using Diagnostic Ratios and Compound-Specific Carbon Isotope Signatures

Jautzy

Ahad

Gobeil

et al. 2013

Environ. Sci. Technol.

105

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“…The δ 13 C values for both TOC (−29.7 ± 0.3‰) and TLE (−30.3 ± 0.1‰) were similar to that reported for bulk Athabasca oil sands bitumen and its maltene, asphaltene, aromatic, and AEO fractions (δ 13 C ∼ −30‰). 3,43,44 At TP1, TP3, and TP4, the δ 13 C signatures for EXT-RES (−27.6 to −26.2‰) were slightly more enriched compared to TOC and TLE, whereas at TP2 the δ 13 C value of EXT-RES (−30.3‰) was similar to TOC and TLE. The close to "radiocarbon dead" Δ 14 C values for TOC (−995 ± 4‰), TLE (−994 ± 1‰), and EXT-RES (−990 ± 8‰) indicate no significant amounts of 14 C in these three carbon pools.…”

Section: ■ Resultsmentioning

confidence: 97%

“…The δ 13 C signatures (‰) of PLFAs extracted from tailings pond sediments (sites TP1, TP2, TP3, and TP4). The dashed line corresponds to the approximate δ 13 C signature (−30‰) of bulk Athabasca oil sands bitumen and its maltene, asphaltene, aromatic, and acid extractable organic (AEO) fractions. ,, …”

Section: Resultsmentioning

confidence: 99%

“…The dashed line corresponds to the approximate δ 13 C signature (−30‰) of bulk Athabasca oil sands bitumen and its maltene, asphaltene, aromatic, and acid extractable organic (AEO) fractions. 3,43,44 Figure 3. The Δ 14 C signatures (‰) of PLFAs extracted from tailings pond sediments (sites TP1, TP2, and TP4) arranged into two groups: PLFAs often associated with petroleum degrading microbes and those which are nonspecific.…”

Section: ■ Discussionmentioning

confidence: 99%

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Direct Evaluation of in Situ Biodegradation in Athabasca Oil Sands Tailings Ponds Using Natural Abundance Radiocarbon

Ahad¹,

Pakdel²

2013

Environ. Sci. Technol.

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Compound-specific stable (δ(13)C) and radiocarbon (Δ(14)C) isotopes of phospholipid fatty acids (PLFAs) were used to evaluate carbon sources utilized by the active microbial populations in surface sediments from Athabasca oil sands tailings ponds. Algal-specific PLFAs were absent at three of the four sites investigated, and δ(13)CPLFA values were generally within ~3‰ of that reported for oil sands bitumen (~-30‰), suggesting that the microbial communities growing on petroleum constituents were dominated by aerobic heterotrophs. Δ(14)CPLFA values ranged from -906 to -586‰ and pointed to significant uptake of fossil carbon, particularly in PLFAs (e.g., cy17:0 and cy19:0) often associated with petroleum hydrocarbon degrading bacteria. The comparatively heavier Δ(14)C values found in other, less specific PLFAs (e.g., 16:0) indicated the preferential uptake of younger organic matter by the general microbial population. Since the main carbon pools in tailings sediment were essentially "radiocarbon dead" (i.e., Δ(14)C ~ -1000‰), the principal source for this relatively modern carbon is considered to be the Athabasca River, which provides the bulk of the water used in the bitumen extraction process. The preferential utilization of the minor amount of younger and presumably more labile material present in systems otherwise dominated by petroleum carbon has important implications for remediation strategies, since it implies that organic contaminants may persist long after reclamation has begun. Alternatively, this young organic matter could play a vital and necessary role in supporting the microbial utilization of fossil carbon via cometabolism or priming processes.

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“…Thermogenic CH 4 associated with Alberta's Lower Cretaceous oils varies between −42 ‰ and −48 ‰ (Jha, Gray and Strausz, 1979;Tilley and Muehlenbachs, 2007), but the prevalence of anaerobic biodegradation in shallow subsurface petroleum reservoirs changes the δ 13 CH 4 composition of heavily degraded oils to between −45 ‰ and −55 ‰, in particular by hydrogenotrophic CH 4 production (Head et al, 2003;Jones et al, 2008). This biogenically over-printed thermogenic CH 4 is present in the mined material of the AOSR, which is potentially released when oil sands are mined, but also during transport, ore preparation, and extraction of bitumen (Johnson et al, 2016).…”

Section: Isotopic Signature Of Ch 4 Sources In the Aosrmentioning

confidence: 99%

Using carbon-14 and carbon-13 measurements for source attribution of atmospheric methane in the Athabasca oil sands region

et al. 2022

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Abstract. The rapidly expanding and energy-intensive production from the Canadian oil sands, one of the largest oil reserves globally, accounts for almost 12 % of Canada's greenhouse gas emissions according to inventories. Developing approaches for evaluating reported methane (CH4) emission is crucial for developing effective mitigation policies, but only one study has characterized CH4 sources in the Athabasca oil sands region (AOSR). We tested the use of 14C and 13C carbon isotope measurements in ambient CH4 from the AOSR to estimate source contributions from key regional CH4 sources: (1) tailings ponds, (2) surface mines and processing facilities, and (3) wetlands. The isotopic signatures of ambient CH4 indicate that the CH4 enrichments measured at the site were mainly influenced by fossil CH4 emissions from surface mining and processing facilities (56 ± 18 %), followed by fossil CH4 emissions from tailings ponds (34 ± 18 %) and to a lesser extent modern CH4 emissions from wetlands (10 ± <1 %). Our results confirm the importance of tailings ponds in regional CH4 emissions and show that this method can successfully distinguish wetland CH4 emissions. In the future, the isotopic characterization of CH4 sources and measurements from different seasons and wind directions are needed to provide a better source attribution in the AOSR.

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The isotopic composition of carbon in the Alberta oil sand

Cited by 8 publications

References 13 publications

Century-Long Source Apportionment of PAHs in Athabasca Oil Sands Region Lakes Using Diagnostic Ratios and Compound-Specific Carbon Isotope Signatures

Century-Long Source Apportionment of PAHs in Athabasca Oil Sands Region Lakes Using Diagnostic Ratios and Compound-Specific Carbon Isotope Signatures

Direct Evaluation of in Situ Biodegradation in Athabasca Oil Sands Tailings Ponds Using Natural Abundance Radiocarbon

Using carbon-14 and carbon-13 measurements for source attribution of atmospheric methane in the Athabasca oil sands region

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