Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New view of dispersants used after Deepwater Horizon oil spill

29.08.2017

Study offers insights into dispersants' human health benefits

New research has uncovered an added dimension to the decision to inject large amounts of chemical dispersants above the crippled seafloor oil well during the Deepwater Horizon disaster in 2010.


At the time of the Deepwater Horizon disaster, oil was streaked across parts of the Gulf of Mexico.

Credit: NOAA

The dispersants, scientists have found, may have significantly reduced the amount of harmful gases in the air at the sea surface -- diminishing health risks for emergency responders and enabling them to keep working to stop the spill and clean it up sooner.

The results were published today in the journal Proceedings of the National Academy of Sciences.

The research team included Jonas Gros, Scott Socolofsky, Anusha Dissanayake and Inok Jun of Texas A&M University; Lin Zhao and Michel Boufadel of the New Jersey Institute of Technology; Christopher Reddy of the Woods Hole Oceanographic Institution; and J. Samuel Arey of the Swiss Federal Institute of Aquatic Science and Technology.

The study was funded by the Gulf of Mexico Research Initiative and the National Science Foundation (NSF).

"In 2010, when NSF began rapid response funding for research on Deepwater Horizon, it was important to characterize the initial conditions of the spill such as plume dynamics and ecological effects," says Don Rice, a program director in NSF's Division of Ocean Sciences, which supported the new research. "These scientists and others did just that. As the findings of this study clearly demonstrate, the discoveries of basic scientific research and the practical applications that follow in their wake are often unanticipated."

In the midst of the Deepwater Horizon crisis, officials made the decision to, over 67 days, inject more than 700,000 gallons of chemical dispersant above the oil rig's severed wellhead at the bottom of the gulf.

The aim was to break the petroleum into smaller droplets in the deep sea to diminish oil slicks and reduce the amount of harmful gases rising to the ocean surface.

The new study demonstrates a beneficial effect of the dispersants: The subsea dispersant injection may have allowed emergency responders to literally breathe easier.

By breaking petroleum into smaller droplets that dissolved faster in the deep ocean, the dispersants decreased the amounts of volatile toxic compounds that rose to the surface and into the air.

This process improved air quality for the responders and likely reduced the number of days when responders were forced to don respirators or suspend cleanup efforts.

Dispersants have been applied to oil slicks on the ocean surface for half a century to break petroleum into smaller droplets that dissipate and to keep oil from reaching ecologically sensitive coastlines.

But they had never been used at the unprecedented depth of 5,000 feet beneath the surface, where an estimated 7,500 tons per day of oil and 2,400 tons per day of natural gas were jetting from the ruptured wellhead.

That flow rate is equivalent to 57,000 barrels per day of oil and 92 million cubic feet per day of gas at the sea surface.

During the period studied, an inverted funnel, or "top hat," that was placed directly above the wellhead prevented 19,000 barrels per day of oil from escaping into the sea.

In the new study, the scientists built and tested a mathematical model that simulated the complex chemical and physical interactions among water, oil, gas and dispersant during Deepwater Horizon.

The researchers focused on the period starting June 3, 2010, when engineers cut the riser pipe at the wellhead, through July 15, 2010, a timespan when a large number of scientific observations were collected nearby in the air and ocean.

To test the model's ability to simulate the real-world disaster, the scientists compared its predictions to these observations.

Nearly all the comparisons aligned with the model's output, indicating that the model replicated many aspects of what happened to the oil and gas under the ocean surface.

The team then ran the model to see what would have happened if dispersants had not been injected above the wellhead during the same time period.

The results indicated the deep-sea dispersant injection did have a profound effect on air quality at the ocean surface.

The injection of the subsea dispersant caused the turbulent jet of petroleum fluids to form oil droplets that were about 30 times smaller by volume than they would have been without dispersants.

This subtle change caused many volatile petroleum chemicals to dissolve more rapidly. Most of the highly toxic benzene and toluene in the oil were transported away in deep currents and likely would have biodegraded within weeks, say the scientists.

The dispersant injection, according to the model, decreased the overall concentration of all volatile organic chemicals in the atmosphere by a modest amount, about 30 percent.

But it also significantly reduced the amount of chemicals most harmful to humans, such as benzene and toluene. The atmospheric concentration of benzene, for example, decreased by about 6,000 times, dramatically improving air quality.

Without the dispersant injection, the model showed that benzene concentrations in the air 2 meters above the sea surface would have been 13 times higher than the levels considered acceptable to breathe during a 10-hour working day or a 40-hour work week, based on guidelines by the National Institute of Occupational Safety and Health.

However, with the dispersant injection, the model showed that atmospheric benzene concentrations were 500 times lower than the levels considered acceptable to breathe.

The researchers believe that clean-up delays would have been more frequent if the subsurface dispersant injection had not been applied.

Media Contact

Cheryl Dybas
cdybas@nsf.gov

 @NSF

http://www.nsf.gov 

Cheryl Dybas | EurekAlert!

More articles from Earth Sciences:

nachricht Colorado River's connection with the ocean was a punctuated affair
16.11.2017 | University of Oregon

nachricht Researchers create largest, longest multiphysics earthquake simulation to date
14.11.2017 | Gauss Centre for Supercomputing

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>