Fugitive Emissions of Volatile Organic Compounds from a Tailings Pond in the Oil Sands Region of Alberta

Abstract

Tailings ponds in the oil sands (OS) region in Alberta, Canada, have been associated with fugitive emissions of volatile organic compounds (VOCs) and other pollutants to the atmosphere. However, the contribution of tailings ponds to the total fugitive emissions of VOCs from OS operations remains uncertain. To address this knowledge gap, a field study was conducted in the summer of 2017 at Suncor’s Pond 2/3 to estimate emissions of a suite of pollutants including 68 VOCs using a combination of micrometeorological methods and measurements from a flux tower. The results indicate that in 2017, Pond 2/3 was an emission source of 3322 ± 727 tons of VOCs including alkanes, aromatics, and oxygenated and sulfur-containing organics. While the total VOC emissions were approximately a factor of 2 higher than those reported by Suncor, the individual VOC species emissions varied by up to a factor of 12. A chemical mass balance (CMB) receptor model was used to estimate the contribution of the tailings pond to VOC pollution events in a nearby First Nations and Metis community in Fort McKay. CMB results indicate that Suncor Pond 2/3 contributed up to 57% to the total mass of VOCs measured at Fort McKay, reinforcing the importance of accurate VOC emission estimation methods for tailings ponds.

Characterization and Dynamics of Residual Organics in Oil Sands Fluid Fine Tailings

“…37,60,61 The table also includes the corresponding values of the clay−water ratio (CWR) determined based on the clay fraction. The larger organic content of FFT-2 is consistent with previous data for tailings of similar origin 8,19 and likely reflects the presence of residual bitumen as well as the unrecovered organic solvents used in the froth treatment process. 3.1.…”

“…2,4,17,18 These tailings are generally characterized by a higher content of residual organics (bitumen and solvents) and a higher percentage of light hydrocarbons. 19,20 Tailings containing solvents are also known to be susceptible to methanogenic processes resulting in the release of greenhouse gases. 18,19,21 Although the residual organic fraction of tailings only accounts for a few % of the total composition by weight, it is viewed as a liability for four reasons.…”

“…19,20 Tailings containing solvents are also known to be susceptible to methanogenic processes resulting in the release of greenhouse gases. 18,19,21 Although the residual organic fraction of tailings only accounts for a few % of the total composition by weight, it is viewed as a liability for four reasons. First, the residual organics are a substrate leading to fugitive methane emissions.…”

Improving Insights on Air Pollutant Mixtures and Their Origins by Enhancing Local Monitoring in an Area of Intensive Resource Development

“…25,26 Some of these tailings ponds have also been shown to be a large source of "BTEX" compounds (benzene, toluene, ethylbenzene, and xylenes). 25,27 PC5 reflects a different VOC mixture dominated by 2methylpentane, which is a distinguishing feature of the paraffinic diluents/solvents particularly associated with SAJ. 28 Hexane, benzene, and toluene are also associated with PC5.…”

“…With respect to PC1, co-emission of methane with the diluents/solvents could be occurring at points downstream of mining as part of the process of separating bitumen, sand, and water and/or collection of tailings. For example, methane emissions occur directly from the tailings ponds as a result of the biogenic activity in the water column. , Some of these tailings ponds have also been shown to be a large source of “BTEX” compounds (benzene, toluene, ethylbenzene, and xylenes). , …”