Reproductive, Immune, and Physiological End Points in Tree Swallows on Reclaimed Oil Sands Mine Sites

Abstract

Wild nestling tree swallows (Tachycineta bicolor) inhabiting reclaimed wetlands receiving tailings or water from mine tailings ponds on oil sands mine sites were the subjects in a multiyear study to determine the ecological viability of these areas. Spanning two field seasons, immune function, reproductive performance (clutch size and mass, hatching success), nestling growth and survival, and diet of tree swallows were examined on six wetlands. One aspect of immune function, the T-lymphocyte proliferative response, was assessed in vivo using a phytohemagglutinin skin test. Hepatic ethoxyresorufin-O-deethylase (EROD) activity provided a biomarker of exposure to oil sands contaminants in the tree swallow nestlings. Results show that there were no differences among reclaimed wetland sites for tree swallow reproductive success, nestling growth rate, and immune response that could be attributed to tailings or tailings pond water additions. Increased EROD activity confirmed the presence of xenobiotics in the diets of nestlings from two sites, while the main reference site was relatively free of EROD-inducing compounds. Dietary analyses showed that 84% of the food items of the tree swallow nestlings were of aquatic origin, likely from the local wetlands, and thus would be expected to provide a good reflection of biological effects of any mining-related contaminants accumulating through the food chain.

Stress response, biotransformation effort, and immunotoxicity in captive birds exposed to inhaled benzene, toluene, nitrogen dioxide, and sulfur dioxide

“…Similarly, increased hepatic EROD was stimulated in juvenile Lesser scaup (Aythya affinis), but not in tree swallow nestlings after intraperitoneal exposure to β-naphthaflavone (Melancon et al, 2006). In oil sands-related studies, hepatic EROD induction was increased in nestling tree swallows inhabiting wetlands receiving industrial effluents (Gentes et al, 2006;Smits et al, 2000), but not different in ducklings raised on such wetlands, even when PAHs (pyrene and naphthalene) were found in bile (Gurney et al, 2005). Similar to our results, natural exposure to air contaminants also induced hepatic EROD activity in tree swallows exposed to contaminant emissions from the oil sands (Cruz-Martinez et al, 2014).…”

“…Aquatic contaminants typical of the oil sands region, such as naphthenic acids (NAs) and polycyclic aromatic hydrocarbons (PAHs), have induced hepatic EROD in fish (Colavecchia et al, 2007;Tetreault et al, 2003), wood frogs (Hersikorn and Smits 2011), and birds including tree swallows (Smits et al, 2000, Gentes et al, 2006 and ducks (Gurney et al, 2005). Similarly, immunotoxic effects, including decreased circulating leukocytes and decreased antibody response to a bacterial pathogen, have been described in fish (Rainbow trout Oncorhynchus mykiss) exposed in situ to oil sands processed waters (OSPW) and experimentally to NAs (Leclair et al, 2013;McNeill et al, 2012).…”

Levels of polycyclic aromatic hydrocarbons and dibenzothiophenes in wetland sediments and aquatic insects in the oil sands area of Northeastern Alberta, Canada

“…Consolidated tailings water is tailings water to which calcium sulphate has been added to accelerate flocculation and settling of fine tails (Gurney et al 2005). NW has been described in other studies that have examined the effects of oil sands-process water on biota (Bendell-Young et al 2000;Smits et al 2000;Gurney et al 2005). HP is a small, emergent vegetationdominated wetland with little open water.…”

“…Concern has been raised about the potential for exposure of fish and aquatic wildlife to PAHs in reclaimed oil sands lakes and wetlands (Van den Heuvel et al 1999;Smits et al 2000;Gurney et al 2005). However, there is little information about levels of PAHs in food organisms of fish and aquatic wildlife in oil sands aquatic ecosystems.…”

Water level management and contaminant exposure to tree swallows nesting on the Upper Mississippi River†

“…Tree swallows will readily use nest boxes, so study sites can be established at specific locations of interest. They feed near their nest box (<400 m, Quinney and Ankney 1985) on emergent aquatic insects (Blancher and McNicol 1991;Mengelkoch et al 2004;Smits et al 2000) so residues in their tissues reflect sediment contamination for those chemicals that transfer into the biota (Fairchild et al 1992). They also will nest relatively densely so adequate sample sizes can be obtained for chemical and other analyses.…”