Monitoring of classical, oxidized, and heteroatomic naphthenic acids species in oil sands process water and groundwater from the active oil sands operation area

Non‐target profiling of bitumen‐influenced waters for the identification of tracers unique to oil sands processed‐affected water (OSPW) in the Athabasca watershed of Alberta, Canada

“…Representative total‐ion chromatograms (TICs) for each of the four sample groupings are depicted in Figure 1, and are consistent with previous analyses illustrating the high complexity inherent in oil sands mixtures of organics 19,21,32 . Visually, the TICs of each group type are characterized by unresolved humps spanning large retention time ranges (9–22 min) with few individual peaks evident other than the internal standards at 13.93 and 16.97 min.…”

“…The fact that three of the four final tracer candidates were sulfur-containing is consistent with literature on sulfur-containing species as being diagnostic of industrial sources of bitumen. 27,32,55 In addition, the fact that all four entities were detected in DP4 and DP5 samples provides further support to the conclusion of Hewitt et al 20 that OSPW-affected groundwater is reaching the Athabasca River system adjacent to Tar Island Dyke.…”

“…Previous non‐target studies have applied two‐dimensional chromatographic techniques and/or HRMS instrumentation to profile heteroatomic ion classes (O 2 S, etc.) that may have diagnostic potential for tracing OSPW 27,32,37 . Here, we advanced the state of knowledge beyond heteroatomic classes to postulating structures for unknown chemical species that could be unique to OSPW seepage.…”

“…This mixture of organics has been termed supercomplex 21 and is similar in chemical profile to natural bitumen‐affected waters, making source discrimination difficult and hampering previous attempts to detect seepage 14,17,19,21–24 . Historically, attempts to identify OSPW‐affected groundwater have considered total naphthenic acids (NAs), various geochemical indicators (major cations and anions), synchronous fluorescence spectroscopy (SFS) detection of aromatic acids, a variety of isotopic tracers, and ratios of O 2 :O 4 heteroatom ion classes and SO n ‐containing species determined by ultrahigh‐resolution mass spectrometry 15,16,18,25–37 . Frank et al 14 applied a two‐tiered screening approach (Level‐1; geochemistry, SFS), and advanced separation or higher resolution methods for profiling acid‐extractable organics (AEOs, Level‐2).…”

“…14,17,19,[21][22][23][24] Historically, attempts to identify OSPW-affected groundwater have considered total naphthenic acids (NAs), various geochemical indicators (major cations and anions), synchronous fluorescence spectroscopy (SFS) detection of aromatic acids, a variety of isotopic tracers, and ratios of O 2 :O 4 heteroatom ion classes and SO ncontaining species determined by ultrahigh-resolution mass spectrometry. 15,16,18,[25][26][27][28][29][30][31][32][33][34][35][36][37] Frank et al 14 applied a two-tiered screening approach (Level-1; geochemistry, SFS), and advanced separation or higher resolution methods for profiling acid-extractable organics (AEOs, Level-2). Level-2 methods that showed promise in source discrimination were qualitative GC × GC/TOF-MS analyses of two groups of monoaromatic naphthenic acids (Families A and B) which were elevated in OSPW and OSPW-influenced groundwater.…”