PH25 Wildlife Ecotoxicology II
Exhibit Hall
8:00 AM - Thursday
(PH289) Effects of petrochemical contaminants from Oil Sand mining on tree swallows: naphthenic acids toxicity.
Gentes, M-L1, Smits, J2, Waldner, C3, 1 Department of Veterinary Pathology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada2 Department of Veterinary Pathology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada3 Department of Large Animal Clinical Sciences, Saskatoon, Saskatchewan, Canada
ABSTRACT- The Alberta Oil Sands are one of the world′s largest oil deposits. The extraction process generates vast amounts of waste-water destined for environmental release once mining has ceased. Wet landscape reclamation consists of creating wetlands and lakes to allow detoxification of mine effluents after released. Tailing water is detrimental to aquatic biota, partly due to Naphthenic Acids (NAs). NAs are natural constituents of petroleum found in high concentrations in tailing water. Related mammalian toxicity has been described using laboratory rodents but there are no data regarding effects in wild birds, which are exposed on reclaimed areas. Tree swallows, an ideal sentinel species, feed on emergent aquatic insects whose larvae develop in contact with contaminants. Wild tree swallows were studied: a) on reclaimed wetlands, naturally exposed to contaminants in tailing water and b) experimentally exposed to NAs. Biological endpoints (reproductive success, nestling growth, survival) and physiological endpoints (hepatic detoxification enzymes, histopathology, hematology, blood biochemistry, DNA strands breaks, immune function, thyroid hormones) were used to characterize health effects from exposure to a) tailings contaminants and b) NAs alone. Inclement weather caused dramatic mortality and high parasitism in all study groups but reproduction (adults) and survival (nestlings) were particularly compromised in birds on the reclaimed wetlands. Experimental exposure to NAs significantly induced hepatic enzymes (EROD, BROD, PROD) and caused abnormal hepatic glycogen accumulation. Increased physiological demands due to contaminants exposure may compromise nestlings′ ability to cope with natural stressors such as low temperature and parasites.
Key words: Oil Sands , mine reclaimation, tree swallow, Naphthenic acids