http://www.tunisiesoir.com/tech/tech-research-suggests-dispersants-suppress-oils-natural-ability-to-biodegrade-report-9592-2018/
[This in addition to research which indicates Corexit has very limited
effectiveness in cold water, and a very short effective time from
application.
[https://www.restco.ca/RESTCo%20to%20Carl%20Brown%20re%20Corexit%20Approval.pdf]
In simple terms, it creates long-term environmental harm in return for a
short-term cosmetic benefit. In a rational examination, it would not
pass a Net Environmental Benefit Analysis study.]
Tech: Research suggests dispersants suppress oil’s natural ability to
biodegrade
– November 1, 2018
By James M. Patterson
A 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.”
The team’s research, led by Claire Paris, professor of ocean sciences at
UM, founded on an unprecedented volume of data publicly available
through the Gulf of Mexico Research Initiative Information and Data
Cooperative (GRIIDC), demonstrated that the formation of the massive
deepwater oil plumes was unrelated to the new response. They further
show, in agreement with previous studies, that plumes of oil persisted
in the Gulf months after the spewing wellhead was capped 87 days later.
The powerful chemical dispersant, called Corexit, may have added to the
ecological damage by suppressing the growth of natural oil-degrading
bacteria and by increasing the toxicity of the oil itself.
“Our earlier work using computer modeling and high-pressure experimental
approaches suggested that pumping chemical dispersants at the spewing
wellhead may have had little effect on the amount of oil that ultimately
surfaced. But empirical evidence was lacking until the release of the BP
Gulf Science Data. When completely different approaches converge to the
same conclusion, it is time to listen,” said Paris. “There is no real
trade-off because there is no upside in using ineffective measures that
can worsen environmental disasters.”
As the oil industry drills in deeper and deeper water, it must find
alternative strategies to manage blowouts, says the study’s authors. The
“capping stack” method in which BP used to stop the wellhead outflow may
be a more effective first response strategy. Bio-surfactants, which are
less toxic and more efficacious to biodegeneration, may offer a viable
alternative for oil spills in shallow waters, according to the researchers.
As part of the massive response and damage assessment effort, a robust
data collection and management strategy was employed, including the BP
Gulf Science Data water chemistry data used in this new study and
compiled under the Gulf of Mexico Research Initiative.
“This type of data management is a strategic asset enhancing both
science and management as it allows scientists to use data-driven
approaches and test important hypotheses for better understanding and
managing future oil spills,” said Igal Berenshtein, a coauthor of the
study and postdoctoral researcher at the UM Rosenstiel School.
On April 20, 2010, the Deepwater Horizon oil rig exploded, releasing 210
million gallons of crude oil into the Gulf of Mexico for a total of 87
days, making it the largest oil spill in U.S. history.
The study, titled “BP Gulf Science Data Reveals Ineffectual Sub-Sea
Dispersant Injection for the Macondo Blowout,” was published on Oct. 30
in the journal Frontiers in Marine Science’s Marine Pollution section.
The study’s authors include: Claire B. Paris, Igal Berenshtein, Marcia
L. Trillo, Robin Faillettaz, and Maria J. Olascoaga of the UM Rosenstiel
School of Marine and Atmosheric Science; Zachary M. Aman of the
University of Western Australia’s School of Mechanical and Chemical
Engineering; Michael Schlüter of Hamburg University of Technology,
Institute of Multiphase Flows; and Samantha B. Joye of the University of
Georgia’s Department of Marine Sciences.
The study was supported by a grant from the Gulf of Mexico Research
Initiative (GOMRI) Center for Integrated Modeling and Analysis of Gulf
Ecosystems (C-IMAGE) II and the Ecosystem Impacts of Oil and Gas Input
to the Gulf (ECOGIG). Data are publicly available through the Gulf of
Mexico Research Initiative Information and Data Cooperative (GRIIDC) at
https://data.gulfresearchinitiative.org.