title: Source Apportionment of Background PAHs in the Peace-Athabasca Delta (Alberta, Canada) Using Molecular Level Radiocarbon Analysis.
abstract: The downstream accumulation of polycyclic aromatic hydrocarbons (PAHs) in the Peace-Athabasca Delta (PAD), an ecologically important landscape, is a key issue of concern given the rapid development of the oil sands industry in Northern Alberta, Canada. In addition to PAHs derived from industrial activity (i.e., oil sands mining) within the Athabasca watershed, however, forest fires and erosion of fossil fuel deposits within both the Athabasca and Peace watersheds are two potentially important natural sources of PAHs delivered to the PAD. Consequently, evaluating the environmental impact of mining activities requires a quantitative understanding of natural, background PAHs. Here, we utilize molecular-level natural-abundance radiocarbon measurements on an amalgamated sediment record from a Peace River flood-susceptible oxbow lake in the northern Peace sector of the PAD to quantitatively discriminate sources of naturally occurring alkylated PAHs (fossil and modern biomass). A radiocarbon mass balance quantified a predominantly natural petrogenic source (93% petrogenic, 7% forest fire) for alkylated PAHs during the past ∼50 years. Additionally, a significant petrogenic component determined for retene, a compound usually considered a biomarker for softwood combustion, suggests that its use as a unique forest fire indicator may not be suitable in PAD sediments receiving Peace watershed-derived fluvial inputs.
authors.affiliation: †INRS Eau Terre Environnement, Québec, Québec G1K 9A9, Canada.
authors.forename: Josué J
authors.initials: JJ
authors.lastname: Jautzy
authors.affiliation: ‡Geological Survey of Canada, Natural Resources Canada, Québec, Québec G1K 9A9, Canada.
authors.forename: Jason M E
authors.initials: JM
authors.lastname: Ahad
authors.affiliation: §Department of Biology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Roland I
authors.initials: RI
authors.lastname: Hall
authors.affiliation: §Department of Biology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Johan A
authors.initials: JA
authors.lastname: Wiklund
authors.affiliation: ∥Department of Geography and Environmental Studies, Wilfrid Laurier University, Waterloo, Ontario N2L 3C5, Canada.
authors.forename: Brent B
authors.initials: BB
authors.lastname: Wolfe
authors.affiliation: †INRS Eau Terre Environnement, Québec, Québec G1K 9A9, Canada.
authors.forename: Charles
authors.initials: C
authors.lastname: Gobeil
authors.affiliation: ‡Geological Survey of Canada, Natural Resources Canada, Québec, Québec G1K 9A9, Canada.
authors.forename: Martine M
authors.initials: MM
authors.lastname: Savard
mesh_terms: D000416:Alberta; D002244:Carbon / Q000032:analysis; D002250:Carbon Radioisotopes; D004784:Environmental Monitoring / Q000379:methods*; D005843:Geography; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*; D045483:Rivers / Q000737:chemistry
chemical_list: D002250:Carbon Radioisotopes; D011084:Polycyclic Aromatic Hydrocarbons; D002244:Carbon