Abstract:

Samples from BP's Deepwater Horizon oil spill were studied by synchrotron radiation-based analytical techniques. The techniques used were X-ray absorption spectroscopy, X-ray diffractometry, X-ray tomography and infrared spectroscopy. X-ray absorption spectroscopy of nickel and vanadium K edges indicated the fate of these metal-bearing porphyrinic compounds. Emulsification seemed to have degraded the nickel-bearing porphyrinic structure. X-ray absorption spectroscopy also showed that the sulfur speciation changed from mostly thiophenic to sulfatic. Expulsion of the paraffins from the asphaltenic structure is evident from X-ray diffractometry. The longer chain alkanes, usually more resistant to weathering are also more evident in the weathered oil. Heavy metal traces from the oil spill riser oil/NWF oil sample near Venice, LA south of Morgan City, LA and controlled burn/emulsified oil/tar balls from Grand Isle, LA and Dauphine Island, AL.

Suggested Citation:

Roy, Amitava. 2015. A Synchrotron Radiation Based Study of BP Deepwater Horizon Oil Spill Samples.. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7XG9P3N

Purpose:

This research project directly addresses (1) the fate and transport of oil and dispersants (2) the biological and ecological impacts of oil and dispersants and (3) spill remediation and recovery by providing an elementally resolved study of the chemistry of the oil as it progresses from the riser to the shore. By understanding the details of the composition of the various compounds within the oil and dispersants, including the elemental valence states taken by the metals within these compounds, we will be able to better understand the solubility, toxicity and bioavailability, and thereby the impact on the Gulf Coast. Spatially-resolved studies of these materials and uptake within the flora and fauna of the region will further our understanding of the impact on the Gulf Coast. Crude oil contains several heavy metals such as vanadium, nickel, chromium, cadmium, and lead with vanadium and nickel usually in highest concentrations. About half the vanadium in crude oil is present as porphyrins (ring-like structures) with concentrations as high as 1600 parts per million (ppm). Toxicological studies have suggested that vanadium is embryo-toxic to ducks. The nickel concentration is generally less than that of vanadium and even though more than half of these metals are not associated with porphyrins the local structure of the metals is very similar. The porphyrins usually do not decompose below 400 to 500C when heated.

Data Parameters and Units:

A Synchrotron Radiation Based Study of BP Deepwater Horizon Oil Spill Samples A. BP Oil FTIR Spectra 1. BP Control Burn 2. BP NWF Oil 3. BP Oil 1800 to 650 4. BP Oil 3800 to 2500 5. BP Oil 4000 to 650 6. BP Riser Oil 7. weathered oil 10 miles from source

Methods:

The X-ray techniques used were X-ray absorption spectroscopy which provides information about speciation, that is, how an element is present rather than total concentration; X-ray diffractometry which identifies the phases present; small and wide angle X-ray scattering which determines structures ranging from microstructure on the colloidal length scale to the crystal structure at the atomic length scale. Parameters include structure, chemical composition, and physical properties.

Instruments:

Experimental lab measurements using synchrotron-based techniques of oil samples. X-ray absorption spectroscopy X-ray diffractometry X-Ray tomography Infrared spectroscopy

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