European Starlings as Sentinels for Health Effects of Urban Air Pollution

Date
2017
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Volume Title
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Abstract
The consequences of exposure to air pollution are widely studied in humans, with urban pollutants associated with a suite of adverse health outcomes. With the complexity of air pollutant mixtures thwarting our full understanding of effects in humans, the consequences to urban wildlife are even less well-understood. The intricate, highly efficient respiratory system of birds makes them more sensitive to airborne toxicants than other vertebrates. The motivation for this study is to identify sensitive, reliable biomarkers of biological effects of air pollutants using wild European starlings (Sturnus vulgaris). This was achieved using two approaches: a field study investigation disclosed the effects of ambient exposure on nestling starlings, whereas experimental exposure of adult starlings to vehicle emissions provided insights under controlled conditions. In both studies, pollutant exposures were measured using several techniques to provide as accurate information as possible. Passive air samplers measured the concentrations of nitrogen dioxide, sulphur dioxide, and volatile organic compounds in ten urban parks in Calgary, Canada during May and June of 2013 to 2015, and during the experiment in May 2016. For the field study, the reproductive success of adult starlings, growth and development of their offspring, biomarkers of oxidative stress, hepatic detoxification effort, and T-cell mediated immune response were evaluated as biomarkers of contaminant effects. The relative contributions of confounding predictors were assessed, while clustering within nest and location were included during analyses. For the experimental study, the same biomarkers were measured in adult, wild-caught, non-breeding starlings, with additional measurements of B-cell immunity, thyroid hormones and histology. Several responses in nestlings indicated that higher exposures to benzene, toluene, ethylbenzene, xylenes (BTEX) and hexane had physiological costs, which, although subtle, may reduce the resilience of nestlings to cope with additional stressors such as fledging. Similarly, subclinical endocrine and immune changes in experimental birds suggest that higher exposures, or the exposure at sensitive life stages, may have population-level consequences.
Description
Keywords
Veterinary Science, Public Health, Toxicology
Citation
North, M. A. (2017). European Starlings as Sentinels for Health Effects of Urban Air Pollution (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/25964