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

Ian J Vander Meulen; Danna M Schock; Joanne L Parrott; Lukas J Mundy; Bruce D Pauli; Kerry M Peru; Dena W McMartin; John V Headley

doi:10.1016/j.scitotenv.2021.146342

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

Sci Total Environ. 2021 Aug 1:780:146342. doi: 10.1016/j.scitotenv.2021.146342. Epub 2021 Mar 20.

Authors

Ian J Vander Meulen¹, Danna M Schock², Joanne L Parrott³, Lukas J Mundy⁴, Bruce D Pauli⁴, Kerry M Peru⁵, Dena W McMartin¹, John V Headley⁶

Affiliations

¹ Department of Civil, Geological and Environmental Engineering, 57 Campus Drive, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5A9, Canada.
² Keyano College, 8115 Franklin Ave, Fort McMurray, AB T9H 2H7, Canada.
³ Environment and Climate Change Canada, Aquatic Contaminants Research Division, 867 Lakeshore Rd, Burlington, Ontario L7T 3M3, Canada.
⁴ Environment and Climate Change Canada, Ecotoxicology and Wildlife Health Division, 1125 Colonel By Drive, Ottawa, Ontario K1A 0H3, Canada.
⁵ Watershed Hydrology and Ecology Research Division, Science and Technology Branch, Environment and Climate Change Canada, 11 Innovation Boulevard, Saskatoon, Saskatchewan, S7N 3H5, Canada.
⁶ Watershed Hydrology and Ecology Research Division, Science and Technology Branch, Environment and Climate Change Canada, 11 Innovation Boulevard, Saskatoon, Saskatchewan, S7N 3H5, Canada. Electronic address: john.headley@canada.ca.

PMID: 33770601
DOI: 10.1016/j.scitotenv.2021.146342

Abstract

Classical naphthenic acids (NAs) are known to be primary aquatic toxicants of concern in the Athabasca oil sands region (AOSR), and are a component of naphthenic acid fraction compounds (NAFCs). Recent studies conducted in the AOSR have examined metals and polycyclic aromatic hydrocarbons in regional wetlands. However, few studies have described NAs and/or NAFCs in AOSR wetlands. To address this gap, we examined NAFC profiles in the water of different wetlands in the AOSR, including naturalized borrow pits (i.e., abandoned pits created by excavation of road-building materials), and opportunistically-formed wetlands associated with reclamation activities. For comparison, NAFC profiles from these wetlands were compared to an opportunistic wetland formed from tailings pond dyke seepage. Samples were prepared using solid-phase extraction and analyzed using negative-ion high-resolution Orbitrap mass spectrometry. Principal component analyses (PCA) revealed patterns to the NAFC profiles in the wetlands. The first distinct grouping of wetlands included water bodies associated with reclamation activities that are located on and/or adjacent to mining overburden. One other wetland, HATS5w, separated from all other wetlands during PCA, and had a unique NAFC profile; detailed examination of NAFCs revealed HATS5w contained the heaviest (i.e., high m/z components) and most unsaturated NAFCs among study locations, demonstrating the usefulness of high-resolution mass spectrometry for characterizing individual wetlands. The NAFCs of HATS5w are also substantially different from bitumen-derived inputs in overburden-adjacent opportunistic wetlands. Collectively, the NAFC profiles presented provide new information on background levels of polar bitumen-derived organics in AOSR wetlands.

Keywords: Naphthenic acids; Non-targeted analysis; Oil sands; Orbitrap mass spectrometry; Reclamation; Wetland chemistry.