Scientists using geometry believe most oil will end up in marshes orsea floor

Carol Forsloff - Virginia Tech College of
Engineering researchers  are using geometry as their weapon of choice
for determining whether the shape of a glob of oil will aid in its
dissolution.

They are utilizing a $60,000
one-year National Science Foundation grant to study how microbes that
are naturally occurring in the environment can be used to eat away the
remaining oil spilled into the Gulf of Mexico following BP's Deepwater
Horizon explosion in April.

The hope is to be able to determine
if the shape of crude oil remnant – be it a flat syrupy sheet or a tar
ball – can affect deterioration rates.

Researchers
will also be examining the effect of oxygen and its lack on hindering
microbe growth and how carbon leaking from the dissipating oil can aid
in helping microbe growth.

The researchers also will study how
a lack of oxygen can hinder microbe growth, and how carbon leaching
from dissipating oil can further fuel these oil-eating microbes.
Researchers will also examine toxic chemicals left behind from the
spill.

“This research has the potential for improving our understanding of the
long-term persistence of chemicals in the environment. In terms of clean
up, there are many problems left to solve regarding the most toxic and
recalcitrant pollutants that dissolve out of liquid sources, not just
associated with oil spills, but at industrial sites, etc.,” says Mark
Widdowson,  who is a professor and assistant department head of CEE.
Widdowson is heading up the present research project with Amy
Pruden-Bagchi, associate professor of CEE.

Widdowson and Pruden-Bagchi maintain oil remnants with geometric shape of flat
surfaces will dissipate slower compared to tar balls that can be
“surrounded” by microorganisms. “Each has a unique geometry where the
rate of dissolution is controlled by exposed surface area,” Widdowson
and Pruden-Bagchi declare. “For oil layers, aerobic biodegradation on
the underside of the deposit will be severely limited by oxygen
availability.”

With 200 million gallons of oil and 500 miles of shoreline affected along
the Gulf Coast, scientists maintain this  “underscores the urgent need
for research that will lead to accurate predictions of the long-term
persistence of the crude oil in coastal environments.”

Certain crude oil buried by sand, debris or grasses, in areas of thickness in
the marshlands especially,  can remain for years. “There are some
reports in Alaska, where you can dig a few inches in the ground and find
oil left over from the Exxon Valdez spill,” said Pruden-Bagchi of the
1989 incident where the spill was anywhere from 11 million to 32 million
gallons.  “Limited oxygen is a big part of the problem.”

Both Widdownson and Pruden-Bagchi have traveled to the area to examine the beaches.

What they found in Alabama, where the oxygen is rich, were no large oil
slicks but instead massive tar balls shaped like raisons and that they
report as having the texture of soft licorice.

Where oxygen levels are poor, more of these are reported.

“Most of the remaining oil will end up in the marshes and on the sea floor,
and may not be obvious as it is on the beaches,” said Pruden-Bagchi.



In the meantime government scientists and independent researchers remain at odds
about how much oil was spilled into the Gulf, how much is left, and
what the specific damage has been and will be in the future.