PM15 Biomarkers
Exhibit Hall
8:00 AM - Monday
(PM225) Ground squirrels as biomonitors of airborne emissions from the petroleum industry.
Kallas, M1, Wayland, M2, Waldner, C1, Wickstrom, M1, 1 University of Saskatchewan, Saskatoon, SK, Canada2 Canadian Wildlife Service, Saskatoon, SK, Canada
ABSTRACT- The cytochrome P450 (CYP450) enzyme complex plays a critical role in the metabolism of environmental contaminants, including polycyclic aromatic hydrocarbons (PAHs) and other organic compounds. Metabolism of PAHs by CYP450IA isozymes occasionally results in intermediates with enhanced toxicity, which may damage DNA. Since PAHs are among the airborne contaminants released from petroleum field facilities, CYP450IA activity was used to assess the toxic potential of chronic exposure to these emissions using a common native rodent, Richardson's ground squirrel (Spermophilus richardsonii), as a model. Ground squirrels were captured at 21 sites in Alberta and Saskatchewan representing a range of exposure to oil and gas field facilities. Hepatic CYP450IA induction was evaluated using the 7-ethoxyresorufin O-deethylase (EROD) assay to measure CYP450IA1 activity, and the 7-methoxyresorufin O-deethylase (MROD) assay for CYP450IA2. A mixed linear model was used to assess whether the number of facilities and the total volumes of gases flared or vented within a defined radius of the trap locations were related to EROD and MROD activity. Increased EROD activity was positively associated with gas venting from small facilities (P=0.0101) and the number of wells (P<0.0001), while MROD activity was unrelated to facility exposure. These results demonstrate the importance of evaluating more than one CYP450 isozyme to assess exposure to toxicant mixtures, and suggest that ground squirrels may be a suitable biomonitor for petrochemical-contaminated ecosystems.
Key words: biomarkers, ground squirrels, cytochrome P450, petroleum hydrocarbons