Spectral fluorescence study of the degradation of crude oil mixed with seawater

During the 2010 Gulf of Mexico oil spill, highly sensitive fluorometers were employed as cost effective tools for in situ tracking of underwater hydrocarbon plumes that resulted from crude oil released at depth. Polycyclic Aromatic Compounds (PAHs) are an important and potentially toxic component of the crude oil signal; however, existing fluorometers are not designed to specifically target PAHs. To further refine instrument sensitivity for targeting PAHs, an investigation of the fluorescence properties (excitation/emission) associated with PAHs from three types of crude oil was undertaken. Using crude oil mixed with seawater and advanced spectrofluorometric techniques PAH fluorescence was quantified for light, mid and heavy density oil samples and changes associated with photodegradation and biodegradation processes were determined. This work will aid in the improvement of in situ instrument development, allowing for more precise and accurate detection and tracking of subsurface hydrocarbon pollution in marine environments.