A multi-media review of polycyclic aromatic compounds in the Alberta Oil Sands Region

This review synthesizes 107 peer-reviewed studies (2001–2025) to provide the first cross-media synthesis of polycyclic aromatic compound (PAC) dynamics in Alberta's Oil Sands Region (OSR), covering air/atmosphere, snowpack and vegetation deposition, surface water, sediment, and biota. Atmospheric PAC concentrations generally fall within ranges reported for rural and semi-rural environments globally, with fugitive dust, wind-blown petroleum coke, and tailings ponds identified as key industrial sources. Atmospheric concentrations and deposition to snowpack and vegetation show consistent exponential distance-decay gradients, with alkylated PAC and dibenzothiophenes dominating near-industrial signatures. In aquatic systems, PAC concentrations are generally low to moderate and infrequently exceed available guidelines, which cover only a few parent PAC. Natural McMurray Formation outcrop erosion and hydrological processes exert strong, sometimes dominant, control over PAC loading in the Athabasca River and its tributaries, complicating source attribution. Lake sediment records nonetheless document post-development increases in PAC fluxes and shifts toward petrogenic signatures, indicating industrial atmospheric inputs. In biota, PAC can cause sublethal developmental, immunological, and endocrine effects, but population-level impacts remain difficult to disentangle from co-occurring stressors such as nutrient enrichment and climate change. Persistent knowledge gaps include analytical heterogeneity across studies, widespread reliance on diagnostic ratios for source attribution, inadequate guidelines, spatial bias toward the surface-mineable Athabasca OSR, and arbitrarily designated central reference points that oversimplify emission heterogeneity. The review recommends standardized analytical frameworks, expanded compound coverage, integrated multi-media monitoring designs, advanced source-attribution tools, comprehensive and validated emissions/release inventories, and meaningful Indigenous community engagement.