Journal of Pollution Effects & Control
Open Access
ISSN: 2375-4397
ISSN: 2375-4397
Chelsea Willis
University of Alberta, Canada
Posters & Accepted Abstracts: Pollut Eff Cont
Atmospheric deposition of contaminants is a concern in the Athabasca Oil Sands (OS) region of Alberta, Canada with potential emission sources including bitumen upgrading facilities, vehicle emissions, volatilization from tailings ponds and blowing dusts from land disturbances including open pit mines, roads and land clearing. We have been monitoring winter-time contaminant loadings in the AOSR using snowpack measurements since 2011 and have found that concentrations of numerous inorganic and organic contaminants, including mercury (Hg) and methylmercury (MeHg; the toxic form of Hg that biomagnifies through food webs), increase with proximity to the major oil sands developments. Although these results suggest that the developments are a direct source of THg and MeHg to nearby watersheds, in situ production of MeHg via snowpack methylation is a possibility given the complex mixture of particles, nutrients and other contaminants present in snowpacks of this region. In addition, in other boreal regions of Canada, dry deposition of MeHg can be 1.4 to 4 times higher under forest canopies than in the open because the forest is an efficient scavenger of aerosols and particulate matter from the atmosphere. In the OS, boreal forest comprises a much larger proportion of the landscape than open areas. To determine the role the forest canopy plays in controlling Hg deposition in the OS, we began quantifying snowpack loadings of Hg and MeHg both in the open and under the forest canopy at 25 sites in winter 2015. To quantify Hg and MeHg deposition under the forest canopy from the spring to fall months, a network of litter fall collectors was also deployed in May 2015. In addition, to determine the origin of MeHg in snowpacks of the OS, a series of in situ incubation experiments using stable isotopes of Hg(II) and MeHg were performed to determine potential rates of Hg methylation and demethylation in OS snowpacks. Results will be presented within the context of 2011-2015 spatial and temporal trends in winter time Hg and metals deposition. This work will improve watershed scale estimates of THg and MeHg loadings and provide a more comprehensive understanding of the potential impacts of MeHg inputs on the ecosystems of the region.
Email: chelsea.willis33@gmail.com