Abstract
Fluorescence 3D excitation emission matrix (EEM) spectra of oil products in artificial seawater were monitored as a function of irradiation time in a solar simulator. EEMs were obtained for an excitation range of 240-400nm and an emission range of 248-830nm; this is the wavelength range typically used in chromophoric dissolved organic matter (CDOM) EEM studies in natural waters. This allows for comparison to prior work on CDOM in an oil-contaminated salt marsh that attributed a fluorescent component in the tryptophan/tyrosine protein-region to oil. For comparison, EEMs were also measured for a broader excitation range of 220-400nm typically used in oil related studies to capture the primary oil peak at lower excitation wavelengths. Fluorescence intensities in both excitation wavelength ranges decayed exponentially with irradiation time consistent with first-order kinetics. There was little change in wavelength for primary oil peaks. However, in the CDOM, wavelength range peaks typically shifted to longer excitation and shorter emission wavelengths, moving into the protein peak region of the CDOM EEM spectrum. This is consistent with a decrease in the complexity of the structure of the organic material. Half-lives for photodegradation ranged from 0.36 to 7.2days for the oil wavelength range and 0.14 to 28days for the CDOM wavelength range. Higher density oils typically had higher degradation rate constants. Peak locations and peak behaviour are consistent with the primary fluorophore in the oil products being PAH-related.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.