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

• Effects of oil sands-related air contaminants on American kestrels and Japanese quail.
• Birds were exposed, in an inhalation chamber, to NO2, SO2, benzene and toluene.
• Kestrels but not quail, had marginally increased hepatic EROD induction.
• Plasma corticosterone was increased in both kestrels and quail.
• B- and T-cell responses were not affected by contaminant gases in either species.
• Japanese quail are an insensitive model for these air contaminants.

In the oil sands of Alberta, Canada, toxicology research has largely neglected the effects of air contaminants on biota. Captive Japanese quail (Coturnix c. japonica) and American kestrels (Falco sparverius) were exposed to mixtures of volatile organic compounds and oxidizing agents (benzene, toluene, NO2 and SO2) in a whole-body inhalation chamber, to test for toxicological responses. Hepatic biotransformation measured through 7-ethoxyresorufin-O-dealkylase (EROD) tended to be increased in exposed kestrels (p=0.06) but not in quail (p=0.15). Plasma corticosterone was increased in the low dose group for quail on the final day of exposure (p=0.0001), and midway through the exposure period in exposed kestrels (p=0.04). For both species, there was no alteration of T and B-cell responses, immune organ mass, or histology of immune organs (p>0.05). This study provides baseline information valuable to complement toxicology studies and provides a better understanding of potential health effects on wild avifauna.