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ENVIRONMENT:
Oil-Eating Bacteria for Antarctica
Marcela Valente
BUENOS AIRES, (Tierramérica) -
Argentine scientists are developing a
biological process for combating oil
spills in the extremely cold
temperatures of Antarctica, where
petroleum exploitation is banned, but
leaks and spills occur in handling and
storing fuels at research stations.
For the past 25 years it has been known
that certain bacteria are useful for
cleaning up oil spills in warmer
climates, where the microorganisms
easily reproduce and decompose
contaminants. This technique might now
be used the immense ice-covered
continent, thanks to the results of
recent experiments.
Biologist Walter MacCormack, of the
Argentine Antarctic Institute, and
biochemist Lucas Ruberto, of the
University of Buenos Aires, set out to
find an efficient ”biological
remediation process” for extremely cold
conditions, like those in Antarctica,
where the average temperature is below
freezing.
Such processes, using microorganisms to
clean up soil contaminated by fossil
fuels or heavy metals, have an
established history, but ”the bacteria
that break down fossil fuels tend to
reproduce at temperatures between 20 and
30 degrees Celsius,” MacCormack told
Tierramérica.
”At four degrees, they do not grow, and
the (decontamination) processes have not
been successful or are too slow to be
considered efficient,” he added.
And there is another problem in applying
this technique in Antarctica.
The Madrid Protocol, which establishes
environmental protection standards for
Antarctica, prohibits the introduction
of viruses, bacteria or any
microorganism from other regions, and
also bans taking samples from the frozen
continent, except for previously
authorised scientific purposes.
The Protocol is an annex of the
Antarctic Treaty, which has been in
force since 1961. There are 45 member
states, with 12 holding consultative
status: Argentina, Australia, Belgium,
Britain, Chile, France, Japan, New
Zealand, Norway, Russia, South Africa
and United States.
These restrictions obligated the
Argentine scientists to use locally
available bacteria -- those found in
Antarctica -- in all of their tests. The
solution came from the ”sicrofilo
facultativo”, which can grow at very low
temperatures but also can adapt to a
climate of more than 20 degrees Celsius.
The experiments were conducted at
Argentina's bases on the Antarctic
Peninsula, 1,000 km south of South
America, where the climate is less
extreme than on greater Antarctica, and
on summer days temperatures can reach 20
degrees.
The studies proved that biological
remediation is possible in Antarctica,
although there is not a single strategy:
it depends on the extent of the
contamination and on the history of the
soils being treated.
For example, the scientists worked with
the bacteria in soils saturated with
petroleum products from nearby fuel
storage tanks.
In that microenvironment of chronic
contamination from repeated gasoline
spills, the soil is ”accustomed” to the
micro-flora, which proliferate in the
presence of phosphorous and nitrogen and
which break up the polluting residues.
To speed up the process in experiments,
more nutrients were added, which
achieved the elimination of 80 percent
of the petroleum derivatives in less
than 60 days.
But in soils contaminated for the first
time by an oil or gasoline spill the
response of the autochthonous microbes
was not as efficient. It was necessary
to introduce more bacteria, isolated in
the spill zone, in order to accelerate
the degradation process.
The scientists stress, however, that
compared to other soil clean-up systems,
like incineration or washing, biological
remediation costs less.
The tests ”confirm that even in extreme
environments there is a remarkable
adaptation of the bacteria to the
contaminating compounds, and that the
(bio-remediation) process could prove
satisfactory during the short summer
period,” conclude MacCormack and Ruberto
in their report.
The same technique can be used in the
southern Argentine region of Patagonia,
where the country's petroleum and
natural gas wealth is concentrated.
Approximately 75 percent of Argentina's
fossil fuel output comes from the
provinces of Neuquén and San Jorge, both
in Patagonia.
Biological clean-up began to be utilized
more than two decades ago as a
complement to the physical removal of
soils contaminated by oil spills.
If an oil tanker sinks and its load
reaches land, microorganisms are set to
work after the initial efforts to remove
the oil that has spilled.
”At sea, physical removal of the
contaminant is more efficient,”
explained MacCormack.
But for soils contaminated by fossil
fuels, clean-up using bacteria is ideal,
according to the researchers.
”The soil contains the spill, so it is
localized and therefore easier to apply
bio-remediation techniques,” MacCormack
said.
The most common accidents on land are
pipeline ruptures or leaks in fuel
storage tanks, as well as spills during
transport.
On the frozen southern continent, where
the Antarctic Treaty bans petroleum or
mineral exploitation, the contamination
risks arise from shipping and storing
fuels.
The most serious accident occurred in
Antarctica in 1989, when the Bahía
Paraíso tanker sank off the coast of the
peninsula, spilling some 600,000 litres
of diesel fuel near the Palmer Base of
the United States, biologist José María
Acero told Tierramérica.
The consequences ”were not catastrophic
because it was light fuel and strong
winds carried it out to sea,” said Acero,
head of environmental management for the
Argentine Antarctic Institute.
But there are many ”small accidents” in
handling fuels for the many research
bases, and these are resolved through
contingency plans, he said.
”In 1994 at Argentina's Marambio Base, a
valve on a fuel tank broke and we lost
80,000 litres of fuel,” but now there
are mechanisms in place to prevent such
accidents.
But MacCormack and Ruberto's discovery
is important because it could be used to
deal with a major spill in Antarctica, a
14 million-square-km natural laboratory
for scientific research.
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