Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Flow rates, fates of Gulf spill contaminants assessed from the air

15.03.2011
Scientists have found a way to use air chemistry measurements taken hundreds of feet above last year's BP Deepwater Horizon oil spill to estimate how fast gases and oil were leaking from the reservoir thousands of meters underwater.

The researchers also determined the fate of most of those gas and oil compounds using atmospheric chemistry data collected from aircraft last June. They say their new methods could be applied to future oil spills, whether in shallow or deep water.

The new analysis has been accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union.

"We present a new method for understanding the fate of most of the spilled gases and oil," says Tom Ryerson, lead author of the report, from NOAA's Earth System Research Laboratory in Boulder, Colo.

"We found that the spilled gases and oil (spilled fluid) obeyed a simple
rule: whether a compound can dissolve or evaporate determines where it goes in the marine environment. That simple rule, and the methods we lay out in this paper, could enable airborne evaluation of the magnitude of future spills."

Knowing where the spilled gas and oil mixture ended up could also help resource managers and others trying to understand environmental exposure levels.

Using the atmospheric measurements and information about the chemical makeup of the leaking reservoir fluid, Ryerson and his colleagues calculate that at least 32,600 to 47,700 barrels of liquid gases and oil poured out of the breached reservoir on June 10, 2010.

This range, determined independently of previous estimates, presents a lower limit.

"Although we accounted for gases that dissolved before reaching the surface, our atmospheric data are essentially blind to gases and oil that remain trapped deep underwater," Ryerson says. Comparison of the new result with official estimates is not possible because this airborne study could not measure that trapped material.

Not including that trapped material, atmospheric measurements combined with reservoir composition information show that about one- third (by mass) of the oil and gas dissolved into the water column on its way to the surface. The team found another 14 percent by mass, or about 258 metric tons per day (570,000 lbs, per day), was lost quickly to the atmosphere within a few hours after surfacing, and an additional 10 percent was lost to the atmosphere over the course of the next 24 to

48 hours.

Among the study's other key findings:

* Some compounds evaporated essentially completely
to the atmosphere, which allowed scientists to make
an estimate of flow rate based solely on atmospheric
measurements and reservoir composition
information.
* Airborne instruments picked up no enhanced levels
of methane, the lightest-weight hydrocarbon in the
leaking reservoir fluid, showing that it dissolved
essentially completely in the water column.
* Benzene -- a known human carcinogen -- and
ethane were found in only slightly elevated
concentrations in the air, meaning they dissolved
nearly completely in the water.
* A number of slightly heavier carbon compounds
ended up in both the air and water, with the precise
fraction depending on the compound. Based on
these data, the team inferred different exposure
risks of mid- and shallow-water marine species to
elevated levels of potentially toxic compounds.
A portion of oil and gas was "recovered" by response activities and piped from the leaking wellhead to the Discoverer Enterprise drill ship on the ocean surface. The research team calculated this recovered fraction by measuring emissions from natural gas flaring aboard the recovery ship. They calculate a recovery rate of 17,400 barrels of reservoir fluid (liquid gas and oil) for June 10, and which accounts for approximately one-third to one-half of the group's total estimate of 32,600 to 47,700 barrels of fluid per day.

Ryerson and his colleagues conclude that the technique they developed could be applied to future oil spills, in shallow or deep water. The research flights, conducted at a minimum of 60 meters altitude (200 feet) above the Gulf surface, were possible because a NOAA WP-3D research aircraft had already been outfitted with sensitive chemistry equipment for deployment to California for an air quality and climate study and was redeployed to the Gulf.

Title:
"Atmospheric emissions from the Deepwater Horizon spill constrain air-water partitioning, hydrocarbon fate, and leak rate"
Authors:
Thomas B. Ryerson, Charles A. Brock, Ru-Shan Gao, David W.
Fahey, Ann M. Middlebrook, Daniel M. Murphy, A.R. Ravishankara, James M. Roberts, and David D. Parrish: Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, Colorado, USA;
Kenneth C. Aikin, Wayne M. Angevine, Fred C. Fehsenfeld, Joost A.
de Gouw, John S. Holloway, Daniel A. Lack, J. Andy Neuman, John B. Nowak, Jeff Peischl, Anne E. Perring, Illana B. Pollack, Joshua P.

Schwarz, J. Ryan Spackman, Harald Stark, Carsten Warneke, and Laurel A. Watts: Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, Colorado, USA, and Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA;

Elliot L. Atlas: Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida, USA;

Donald R. Blake and Simone Meinardi: Department of Chemistry, University of California, Irvine, California, USA;

Richard A. Lueb: Atmospheric Chemistry Division, National Center for Atmospheric Research, Boulder, Colorado, USA.

Contact information for authors:
Thomas B. Ryerson, NOAA Earth System Research Laboratory, Chemical Sciences Division, +1 (303) 497-7531, Thomas.B.Ryerson@noaa.gov

Peter Weiss | American Geophysical Union
Further information:
http://www.agu.org

More articles from Earth Sciences:

nachricht Global study of world's beaches shows threat to protected areas
19.07.2018 | NASA/Goddard Space Flight Center

nachricht NSF-supported researchers to present new results on hurricanes and other extreme events
19.07.2018 | National Science Foundation

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Future electronic components to be printed like newspapers

A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.

The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

A smart safe rechargeable zinc ion battery based on sol-gel transition electrolytes

20.07.2018 | Power and Electrical Engineering

Reversing cause and effect is no trouble for quantum computers

20.07.2018 | Information Technology

Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern

20.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>