Journal Article

Atmospheric emissions from the Deepwater Horizon spill constrain air-water partitioning, hydrocarbon fate, and leak rate

Atlas, E. L., Murphy, D. M., Angevine, W. M., Brock, C. A., Fahey, D. W., Watts, L. A., Holloway, J. S., Meinardi, S., Middlebrook, A. M., Warneke, C., Fehsenfeld, F. C., Peischl, J., Perring, A. E., Roberts, J. M., Pollack, I. B., Spackman, J. R., de Gouw, J. A., Nowak, J. B., Aikin, K. C., Schwarz, J. P., Ravishankara, A. R., Blake, D. R., Stark, H., Neuman, J. A., Ryerson, T. B., Gao, R.-S., Lueb, R. A., Lack, D. A., Parrish, D. D.

2011

Overview

The fate of deepwater releases of gas and oil mixtures is initially determined by solubility and volatility of individual hydrocarbon species; these attributes determine partitioning between air and water. Quantifying this partitioning is necessary to constrain simulations of gas and oil transport, to predict marine bioavailability of different fractions of the gas‐oil mixture, and to develop a comprehensive picture of the fate of leaked hydrocarbons in the marine environment. Analysis of airborne atmospheric data shows massive amounts (∼258,000 kg/day) of hydrocarbons evaporating promptly from the Deepwater Horizon spill; these data collected during two research flights constrain air‐water partitioning, thus bioavailability and fate, of the leaked fluid. This analysis quantifies the fraction of surfacing hydrocarbons that dissolves in the water column (∼33% by mass), the fraction that does not dissolve, and the fraction that evaporates promptly after surfacing (∼14% by mass). We do not quantify the leaked fraction lacking a surface expression; therefore, calculation of atmospheric mass fluxes provides a lower limit to the total hydrocarbon leak rate of 32,600 to 47,700 barrels of fluid per day, depending on reservoir fluid composition information. This study demonstrates a new approach for rapid‐response airborne assessment of future oil spills. Key Points Atmospheric hydrocarbon data define air‐water partitioning of marine oil spills Air‐water partitioning determines oil fate and extent in the marine environment These data permit a unique and robust calculation of oil leak rate

• Publisher: Blackwell Publishing Ltd,American Geophysical Union,John Wiley & Sons, Inc
• Subject: Applied sciences / Atmospheric pollution / Atmospheric sciences / Atmospherics / Bioavailability / Biological oceanography / BP oil spill / Chemical oceanography / Deepwater Horizon / Earth sciences / Earth, ocean, space / Engineering and environment geology. Geothermics / Exact sciences and technology / Fluid dynamics / Fluid flow / Fluids / Geophysics / Hydrocarbons / leak rate / Leaks / Marine environment / Marine geology / marine hydrocarbons / Marine pollution / methane / Natural gas / Natural water pollution / Oceanography / oil fate / Oil spills / Partitioning / Pollutants physicochemistry study: properties, effects, reactions, transport and distribution / Pollution / Pollution, environment geology / Seawaters, estuaries / Troposphere / Water column / Water treatment and pollution