Summary:
This project is designed to help elucidate the transformation and distribution of crude oil components and added dispersants in strategic areas of the Gulf of Mexico and along the projected plume trajectories. Most of the effort will be directed at coastal waters along the west Florida shelf and the Florida Keys, and particularly ecologically sensitive Florida coastal areas. The project will be largely based on laboratory analysis of water samples obtained from cruises of opportunity throughout the region of interest. Samples will be obtained from the vicinity of the spill site (the point source) to distant end-members along the spill transport track.
Of primary interest are the more soluble and readily dispersed oil components which are also typically the more toxic components. These components typically separate from the bulk oil shortly after the oil mixes with seawater. Because of differences in solubility components typically contain multiple functional groups and extended conjugation which make them more reactive chemically and particularly photochemically. These same chemical characteristics offer a method for identification via fluorescence analysis. Since they are optically sensitive, these compounds can be detected and characterized at low concentrations with the use of three dimensional spectra or EEMS. Because of the high sensitivity of the method, this is potentially a powerful tool for identifying these dispersed plumes at great distances from their source. However, the method is less robust in areas containing high concentrations of dissolved humic materials such as those found along the gulf coast states. The fluorescence of these humic materials in coastal environments can significantly interfere with the low level signals from the dispersed plumes.
This problem can be overcome by statistically treating the three dimensional EEMs spectra using PARAFAC analysis. The PARAFAC data analysis should distinguish dispersed plume components from dissolved humic materials and provide a powerful tool for identifying the plumes and characterizing dispersion and transformations of the plumes' chemical components. The EEM spectra will be preformed on both extracted and bulk water samples. To verify the interpretation of the EEM sand PARAFAC data analysis, extracts of the collected samples will be subjected to GC-MS analyses. Samples will be evaluated for total crude oil content and individual component content with the use of appropriate calibration standards. In a similar manner, samples will be evaluated for dispersant content. The results of the rapid analysis and simplicity of the PARAFAC analyses, this technique could become a standard tool for evaluating broad areas of the Gulf oil spill and future oil spills.