Are wild birds in the oil sands region exposed to chemicals associated with mining-related activities? Do they accumulate these chemicals in their bodies? How significant is the impact?
ECCC’s Kim Fernie led the research into examining these questions. Dr. Fernie, along with a team of scientists that included ECCC’s Catherine Soos, Tom Harner and Anita Eng, examined nesting tree swallows in the Athabasca Oil Sands Region (AOSR). Millions of barrels of oil are produced in this area each year. The team examined birds at two sites near mining and related activities and at two sites further removed from these activities. The study was conducted near Fort McMurray, Alberta.
The researchers focused on studying exposure to PACs (polycyclic aromatic compounds) in free ranging tree swallows. PACs are a large group of organic compounds (that includes the polycyclic aromatic hydrocarbons or PAHs) that are found in oil and gas deposits, but are also produced by thermal decomposition of organic matter (e.g., through combustion of fossil fuels, in industrial processes, and during forest fires, etc.). As emerging environmental contaminants, PACs are increasingly being studied across Canada by environmental researchers. While PAC levels in the environment have significantly increased in the oil sands area in recent decades, there have been few studies investigating PAC exposure, accumulation, and associated health effects in wildlife, including birds, living in the Athabasca Oil Sands Region.
An article detailing the results of investigations into the exposure and accumulation of PACs by tree swallows in the Fort McMurray area by Dr. Fernie and her co-authors was published this year in Science of the Total Environment; it is entitled Elevated exposure, uptake and accumulation of polycyclic aromatic hydrocarbons by nestling tree swallows (Tachycineta bicolor) through multiple exposure routes in active mining-related areas of the Athabasca oil sands region.
Results
The study looked at PACs in the birds and the different routes of exposure to PACs for the birds, by measuring PAC concentrations in various samples collected at the study sites concurrently. Dr. Fernie and her team found that PACs were significantly higher in the tree swallow chicks raised at the two oil sands locations, compared to those who were living in the “reference” areas removed from the surface mining operations. The results were consistent among the various types of PACs. In addition, the birds were exposed to and accumulated alkylated-PACs, as well as parent-PACs.
The study also looked at the different routes of exposure to PACs for the birds. The team found that chemicals might be introduced to these birds in a number of ways, including diet, air (inhalation) and water (drinking). The authors determined that the “Tree swallows that bred in close proximity to the oil sands mining sites were exposed to higher air and water concentrations of a complex mixture of 41 of 42 PACs … Nestlings at Oil Sands mining-related sites accumulated higher concentrations of PACs (muscle, feces) than the reference chicks through varying routes of exposure” (Fernie et al. 2018).
The authors also examined whether PAC concentrations in the fecal and muscle samples of the birds were correlated, with the goal of developing a non-lethal tool for research and monitoring purposes and concluded that: “[T]he PAH concentrations in feces and muscle of all chicks were significantly and highly correlated …. Muscle concentrations were significantly greater than fecal concentrations ...” (Fernie et al. 2018).
The authors note that muscle samples are reflective of environmental and/or dietary sources of PAC concentrations. And, since the PACs in muscle samples were highly associated with the PACs in fecal samples, the findings suggest that the collection of fecal samples offers a simple, easy, and non-lethal tool to better understand PACs in the birds breeding in the oil sands region.
Impact
Fernie stresses that exposure to PACs may have profound impacts on wildlife:
“Depending on the concentrations of PACs, it may impact the individual tree swallow’s survival. There are also more subtle effects on the thyroid function of the chicks, and on their ability to thermoregulate (the ability of the birds to stay warm or cool), as well as on their growth and reproduction,” according to Dr. Fernie.
The next step for researchers is to determine the impact of PACs on tree swallows in the oil sands region. Since the paper was released, the team has published two subsequent papers examining the changes in growth, reproduction and thyroid function of the birds, including a more in-depth look at PACs and other environmental challenges encountered by these tree swallows.
Fernie’s research was part of the Canada-Alberta Joint Oil Sands Monitoring Program. You can learn more about the program here.