new study of the Deepwater Horizon response showed that massive quantities of chemically engineered dispersants injected at the wellhead—roughly 1,500 meters (4,921 feet) beneath the surface—were unrelated to the formation of the massive deepwater oil plume.


A University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science-led research team analyzed polycyclic aromatic hydrocarbons (PAHs), the most toxic components of petroleum, based on the BP Gulf Science Data's extensive water chemistry samples taken within a 10-kilometer (6-mile) radius of the blowout site.

The results of this analysis demonstrated that substantial amounts of oil continued to surface near the response site, despite 3,000 tons of subsea dispersants injection (or SSDI)—a new spill response strategy meant to curb the spread of oil and facilitate its degradation.

Dispersants application to manage surface oil spills has been shown to break the oil into small, easily dissolved droplets. However, the Deepwater Horizon was very different in that the oil entered the system at depth. The turbulent energy and pressure at such immense depths not only contributed to the rapid expansion of the spill, but these natural forces helped disperse oil in micro-droplets and render the dispersant ineffective and unnecessary.

"The results of this study are critically important," said the study's coauthor Samantha Joye from the University of Georgia. "This work shows clearly that the eruptive nature of the Macondo discharge was more than sufficient to generate the deepwater oil plume. Further, application of dispersant did not increase the amount of oil in the aqueous phase or change the distribution of oil over depth. These findings should change the way we think about spill response and calls for a reconsideration and reprioritization of response measures."
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