Oil residues from natural and anthropogenic sources persist in the environment, where they undergo chemical and biological degradation over time. Traditional gas chromatographic methods remain effective in the analysis of oil, but are time-consuming when analyzing large sample sets, and cannot be readily deployed in the field. This study is focused on developing techniques to rapidly detect oil in situ, as well as analyze its chemical composition, and determine its source. To this end, we developed a technique to analyze persistent oil residues via attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FT-IR). Samples analyzed in this study originated from both anthropogenic and natural inputs, and were collected from Gulf of Mexico beaches following the 2010 Deepwater Horizon oil spill, and from sites in Prince William Sound, Alaska that contain oil from the 1989 Exxon Valdez oil spill and the 1964 Alaska Earthquake. ATR-FT-IR data useful in characterizing oil residues included specific alkane stretches at 2910 cm-1, 1410 cm-1 and 1376 cm-1 and alkene stretch at 1608 cm-1. Additional peaks at 3990 cm-1, 1712 cm-1 and 1024 cm-1 representing O-H, C=O and C-O respectively qualitatively demonstrated chemical weathering of the oil residues. Ongoing analysis is exploring the utility of ATR-FT-IR to distinguish oil from different sources as well as the limitations of this approach arising from non-oil components present in the sample. Overall, ATR-FT-IR is useful to rapidly gain preliminary data on the composition and weathering of persistent oil residues in the field before undertaking more laborious lab-based techniques.

Rapid characterization of oil residues in the environment by Fourier-transform infrared spectroscopy

2019 Spring National Meeting

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