Identification of persistent oil residues in Prince William Sound, Alaska using rapid spectroscopic techniques

Spectroscopic techniques including X-ray fluorescence (XRF) and attenuated total reflectance – Fourier transform infrared spectroscopy (ATR-FTIR) are used to examine oil residues persisting on shorelines in Prince William Sound that originate from the 1989 Exxon Valdez oil spill and oil released as a consequence of the 1964 Great Alaska earthquake. When coupled to classification models, ATR-FTIR and XRF spectral data can be used to distinguish between the two sources of oil with 92% and 86% success rates for the two techniques respectively. Models indicate that the ATR-FTIR data used to determine oil source includes the CO stretch, the twisting-scissoring of the CH2 group, and the CC stretch. For XRF data, decision tree models primarily utilize the abundance of nickel and zinc present in the oil as a means to classify source. This approach highlights the utility of rapid, field-based spectroscopic techniques to distinguish different inputs of oil to coastal environments. •Spectroscopic techniques enable identification of oil residues in the environment.•Oil from the Exxon Valdez spill is distinguishable from oil from other sources.•Classification models have success rates of 92% and 86% for ATR-FTIR and XRF data.