Emissions from Tailings Ponds to the Atmosphere, Oil Sands Region

Concentrations of Polycyclic Aromatic Hydrocarbons and Total Petroleum Hydrocarbons in Tailings Pond Water in the Oil Sands Region – September 2013

To evaluate evaporation from tailings ponds as a potential source of emissions of pollutants to air, bulk water samples were collected from 8 locations in two ponds at a single facility in the oil sands region over two days in September 2013. Chemical measurements of polycyclic aromatic hydrocarbons (PAHs) and total petroleum hydrocarbons (TPH) were made. PAH data are reported for the sixteen species identified as priority pollutants by the US EPA. TPH refers to the total amount of hydrocarbon compounds. In this dataset, TPH values represent the amount of saturate and aromatic hydrocarbons measured in the tailings pond water samples as determined using specific analytical techniques (fractionation and gas chromatography). PAHs are included on the List of Toxic Substances of the Canadian Environmental Protection Act (CEPA) and are subject to management under the Act. Results suggest that PAH emissions to the atmosphere from tailings pond water are significant when compared to other reported sources in the region, as reported in the paper by Galarneau et al., 2014.

Concentrations and Fluxes of Odours, Reduced Sulphur Compounds (RSCs) and Volatile Organic Compounds (VOCs) Emitted from Tailings Pond Water in the Oil Sands Region – October 2014

To generate estimates of potential emissions to the air from tailings pond water, surface water samples were collected from five locations within a single tailings pond in October 2014. A laboratory flux chamber was used to evaluate potential emissions to the air from tailings pond water. The air was then analysed for reduced sulphur compounds (RSC), volatile organic compounds (VOC) and odour intensity and concentration. VOC and RSC fluxes to the atmosphere from tailings pond water contribute to the overall burden of smog- and odour-causing compounds in the region. Results are presented as concentrations in the generated air and as emission fluxes (i.e. rate of flow of the compound from the water to the air) derived using the flux chamber flow characteristics. Air concentrations measured using laboratory flux chambers simulate the state of the atmosphere under limited conditions and do not represent the full range of values that can arise due to variations in factors such as temperature and wind speed. Ambient air quality objectives (AAQOs) do not apply to air directly above emissions sources such as tailings ponds; nor do they apply to these air data generated from tailings pond water samples.

Multi-method Measurements of Pollutant Emissions from a Tailings Pond, Oil Sands Region - Summer 2017

Tailings ponds in the Athabasca Oil Sands region in Alberta are known to contribute to fugitive emissions of pollutants to the atmosphere (Galarneau et al., 2014 and Small et al. 2015). A measurement study was executed in the summer of 2017 on Suncor Pond 2/3 in collaboration with Suncor, Alberta Environment and Parks and the University of Alberta, branded TAPOS (TAilings POnd Study), to test a combination of different methodologies to quantify fluxes of air pollutants from the pond to the atmosphere. These methodologies included eddy covariance, vertical gradients, inverse dispersion models, and vertical radial plume mapping, to compare between each other and with traditional flux chamber measurements. The overarching objectives were to explore the feasibility of alternative methods to monitor these emissions, and to quantify the emission rates of a number of pollutants, including 40 speciated volatile organic compounds (VOCs), 28 polycyclic aromatic compounds (PAHs), 5 reduced sulfur compounds (RSCs), and greenhouse gases (GHG). PAHs are included on the List of Toxic Substances of the Canadian Environmental Protection Act (CEPA) and are subject to management under the Act. Ambient air quality objectives (AAQOs) do not apply to air directly above emissions sources such as tailings ponds. Measurements commenced on July 28, 2017 and ended on September 5, 2017, producing 39 days of continuous data, mostly at a temporal resolution of around 1 second. The central measurement platform was a 32m mobile tower with air inlets at 4m, 8m, 18m and 32m. Air was drawn from these heights into a trailer housing several trace gas analyzers. At the same heights, the 3-dimensional turbulent wind field, temperature and humidity were recorded. These single-point measurements were complemented by long-path measurements of selected trace gases along the shoreline, as well as integrated sampling onto filter media using active high-volume and passive samplers. There were 13 stainless steel canisters used for grab samples of the air for subsequent gas-chromatography analysis. In addition, 20 samples of pond surface water were taken on 3 days during the study, to estimate emissions using water-atmosphere exchange models and to tie the micrometeorological results to results from 2013 and 2014.

References Galarneau, E.; Hollebone, B. P.; Yang, Z.; Schuster, J., Preliminary measurement-based estimates of PAH emissions from oil sands tailings ponds. Atmospheric Environment 2014, 97, 332-335. Small, C. C.; Cho, S.; Hashisho, Z.; Ulrich, A. C., Emissions from oil sands tailings ponds: Review of tailings pond parameters and emission estimates. Journal of Petroleum Science and Engineering 2015, 127, 490-501.