Posted by: The ocean update | November 11, 2015

BP Oil Spill Dispersants Not Effective, Research Suggests (Gulf of Mexico, USA)

June 26, 2011 (Beth Buczynski). It took over a year, but earlier this month the Environmental Protection Agency finally released a partial list of the chemical components in oil dispersants used to “clean up” portions of the BP oil spill in the Gulf of Mexico

June 26, 2011 (Beth Buczynski). It took over a year, but earlier this month the Environmental Protection Agency finally released a partial list of the chemical components in oil dispersants used to “clean up” portions of the BP oil spill in the Gulf of Mexico

November 11th, 2015. Dubbed as the ‘worst environmental disaster’ in the United States — the Deepwater Horizon oil spill, informally called the BP oil spill disaster, in the gulf of Mexico killed 11 workers more than five years ago, and discharged more than 4.9 million barrels of oil that damaged marine and wildlife habitats.

After the explosion of the Deepwater Horizon oil rig, the sea floor gusher spewed millions of gallons of oil for 87 days, before it was capped in July 2010. After the accident, authorities have decided to apply a dispersant called Corexit into the Gulf.

This chemical agent, Corexit 9500, was applied from air onto the oil slick. The agent would break the oil slick into smaller clumps, and prevent it from reaching nearby beaches and other protected habitats.

Authorities said Corexit would also help oil-eating bacterias get rid of slick.

After several years, the oil appeared to be getting cleaner — but according to researchers from the University of Georgia, scientists and government officials didn’t monitor the microbes and chemicals in the Gulf, so they recreated the application inside laboratories to see if spraying the chemical agent was effective.

According to a study published Monday, with lead author Samantha Joye from the University of Georgia, Corexit 9500 didn’t help microbes at all, and even hurt one key oil-digesting bacteria.

Marine scientist Joye and colleagues have recreated the scene in a lab, with the Corexit 9500, BP oil and seawater from the Gulf of Mexico — and found that the dispersants “did a great job” when it comes to taking the oil off the surface, but it didn’t lower the presence of microbes. The agent also increased the presence of a bacteria called colwellia — but this family of microbes is not an effective oil-muncher.

Their tests with more than 50,000 bacterias show that Corexit 9500 has been suppressing marinobacter, one of the main groups of oil eaters on sea water. Marinobacters eat oil all the time and comprise about 3 percent of the bacteria in normal water. Joye said when there’s oil in water, they eat and multiply like crazy until they are as much as 42 percent of the bacteria. But their tests show that after putting Corexit 9500 on water, Marinobacters stopped multiplying.

Study co-author Sara Kleindienst University of Tübingen in Germany said in a statement that during the oil spill, the oil-eating marinobacter were not abundant in deep-water plume samples. “Whether natural hydrocarbon degraders were outcompeted by dispersant degraders or whether they were directly affected by dispersant-derived compounds needs to be resolved in future studies,” she said.

The study revealed that 7 million liters of dispersants were applied in the Gulf after the spill.

According to authorities, most of the oil from the disaster has evaporated or dissolved, but as of April, more than 10 million gallons of oil remain on the sea floor. Some reports also suggest that lumps of oil can still be found in marshes along the coast near the accident area.

In addition to 11 deaths (and microbes that have died), authorities reported back in May that the BP Oil spill of 2010 killed a lot of dolphins — as in, a lot. According to a NOAA study, dolphins most likely inhaled the fumes from the oil on the ocean surface. Aside from dolphins, researchers also added that exposure to oil fumes is one of the most common causes of chemical inhalation injury in other animal groups.

In July, BP agreed to pay more than $18.7 billion. States affected by the spill will receive $7.1 billion, payable over 18 years, while $5.5 billion was awarded to Clean Water Act penalties, and it’s payable over 15 years.

The research from the University of Georgia about the ineffective use of dispersants on the Gulf is published in the journal Proceedings of the National Academy of Sciences. Interested readers can access the documents at the website.

Citation : S. Kleindienst, M. Seidel, K. Ziervogel, S. Grim, K. Loftis, S. Harrison, S. Y. Malkin, M. J. Perkins, J. Field, M. L. Sogin, T. Dittmar, U. Passow, P. M. Medeiros, S. B. Joye. Chemical dispersants can suppress the activity of natural oil-degrading microorganismsProceedings of the National Academy of Sciences, 2015; DOI: 10.1073/pnas.1507380112




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