A wintertime investigation of atmospheric deposition of metals and polycyclic aromatic hydrocarbons in the Athabasca Oil Sands Region, Canada

With planned expansion of oil sands facilities, there is interest in being able to characterize the magnitude and extent of deposition of metals and polycyclic aromatic hydrocarbons (PAH) in the Athabasca Oil Sands Region (AOSR) of Alberta. A study was undertaken using a bulk collection system to characterize wintertime atmospheric deposition of selected inorganic and organic contaminants in the AOSR. The study was carried out from January to March 2012 at two sampling sites near (within a 20 km circle of oil sands development) and two sampling sites distant (> 45 km) to oil sands development. Triplicate bulk samplers were used to estimate precision of the method at one distant site. Monthly deposition samples were analyzed for 36 metals, ultra-low mercury, and 25 PAHs (including alkylated, and parent PAH). At the two sites located within 20 km of oil sands development, 3-month wintertime integrated deposition for some priority metals, alkylated and parent PAH were higher compared to distant sites. Deposition fluxes of metals and PAH were compared to other available bulk deposition studies worldwide. Median bulk measurement uncertainties of metals and both PAH classes were 26% and within ± 15%, respectively suggesting that the bulk sampling method is a potential alternative for obtaining future direct measures of wintertime metals and PAH deposition at locations without access to power in the AOSR.