What Ever Happened to the BP Oil Spill? Current Research on Polynuclear Aromatic Hydrocarbons in the Gulf of Mexico
As part of the Civil and Environmental Engineering graduate seminar lecture series, Marco Kaltofen a Ph.D. candidate for civil engineering presented a lecture on the current research on polynuclear aromatic hydrocarbons in the Gulf of Mexico.
This investigation measured the concentration and stability of polynuclear aromatic hydrocarbons, (PAH), and total petroleum hydrocarbons, (TPH), in crude oil-contaminated seawater of the Gulf of Mexico. PAH and TPH were also measured in laboratory-mixed samples of unfiltered Gulf of Mexico seawater, BP crude oil, and Nalco Corexit® dispersants. The investigation showed that, for a given crude concentration, [PAH]water was dependent on the ratio of dispersant to crude oil spikes in seawater.
The concentrations of PAHs and TPH increased in the water column when Corexit® oil dispersant products were added to seawater/petroleum mixes. Visually, dispersant addition resulted in immediate breakup of the crude oil NAPL layer on the water surface. Analyses proceeded by solvent extraction followed by GC-FID or GC/MS-SIM. Tarball/dispersant interactions in seawater were examined by these same techniques. Adding dispersant to tarballs in seawater had no significant observable effect, nor did [PAH]water rise appreciably.
In the field, water column PAH and TPH concentrations were quantified in samples of seawater collected from inshore waters of southern Louisiana and western Florida. Toxic petrogenic compounds are generally more bioavailable when in the water column, rather than sequestered in nonaqueous phase liquids on the water surface. Increases in [PAH]water results in a greater amount of PAHs which may be available for uptake by marine organisms. PAH and TPH were measured in tissues of organisms, (oysters, jellyfish, crabs, tunicates, finfish, and crab larvae), collected from waters with known PAH and TPH contamination in the Gulf of Mexico.
March 1, 2012