Vibrational spectroscopy as a tool to investigate the effects of environmental contaminants in predatory birds

Abstract

Predatory birds are vulnerable to contaminants in the environment due to their high trophic position and long lifespans. They are also important sentinel species so tools are needed to measure and monitor contaminants, not only to protect avian populations, but to confer protection to lower trophic species as well. Vibrational spectroscopy is an economic, high-throughput technique that can be used to determine biomolecular profiles and can also identify alterations induced by exposure to environmental contaminants. In this thesis, avian tissues and cells have been analysed for underlying biochemistry and for effects caused by exposure to common environmental pollutants, using attenuated total reflection Fourier-transform infrared (ATR-FTIR) and Raman spectroscopy techniques with multivariate analysis. By analysing untreated predatory bird tissues, vibrational spectroscopy was shown to reveal fundamental, underlying biochemistry. The ability to generate tissue-specific spectral profiles allows the identification of biomolecular compositional differences which may influence the effect of contaminant exposure. Brain tissue from wild, free-flying predatory birds was similarly analysed to assess the effects of ‘real-world’ contaminant exposure levels. Vibrational spectroscopy was demonstrated as a sensitive technique capable of distinguishing the effects of high and low contaminant exposures, protein secondary structures and elucidating sex- and age-dependant spectral differences. An avian cell line was also analysed using ATR-FTIR which was able to determine the biomolecular composition and identify significant differences between cell types. This not only verifies the suitability of such techniques for cell-based investigations but also shows they are sensitive enough to detect biochemical variations at the cellular level. ATR-FTIR was further demonstrated as a tool to identify alterations induced by single and mixtures of contaminants and as a screening tool to identify interactions in a mixture. Overall, vibrational spectroscopy was established as a sensitive tool to study the effects of environmental contaminants in avian tissues and cells, however, further research is necessary to fully validate the technique.