A Tale of Two Spills: The Exxon Valdez and the Deepwater Horizon (BP) : Behavior of oil, persistence, and biodegradation

A Tale of Two Spills: The Exxon Valdez and the Deepwater Horizon (BP) : Behavior of oil, persistence, and biodegradation

Michel C. Boufadel, PhD, PE, F. ASCE, P.Hydro.
Professor, John A. Reif, Jr. Dept. Civil & Environmental Engineering

boufadel@gmail.com      ;     http://nrdp.njit.edu

Our group has been investigating both the Exxon Valdez oil spill in Alaska and the BP Deepwater Horizon oil spill in the Gulf of Mexico, which allows us to provide a holistic comparison of the two. For the Exxon Valdez oil spill, we found that the beaches in Prince William Sound Alaska consist of two layers, the upper one has a much higher permeability than the lower one, and the oil is trapped a few centimeters below the interface. We also found that low oxygen concentrations in the pore water prevented the biodegradation of oil. A bioremediation study that we conducted on four beaches revealed enhanced oil biodegradation with various degrees of success. The DWH blowout occurred at 1500 m depth in the Gulf of Mexico, and the dispersion of oil (breakup into small droplets) was a critical factor in the transport of oil, as large droplets rise rapidly to the water surface, whereas small droplets get advected by sea currents. We present a new model for oil droplet formation that accounts for both the interfacial tension of oil and its viscosity, and we provide simulation results for the DWH blowout. We also present results on the movement of oil on the surface and its subsequent deposition on the shorelines. Our simulation suggested that around 22,000 tons of oil were deposited.