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What are Oil Spills?
• An oil spill is the release of a liquid petroleum hydrocarbon into the
environment, especially marine areas, due to human activity, and is a
form of pollution.
• The term is usually applied to marine oil spills, where oil is released
into the ocean or coastal waters, but spills may also occur on land.
• Oil spills may be due to releases of crude oil from tankers, offshore
platforms, drilling rigs and wells, as well as spills of refined petroleum
products and their by-products, heavier fuels used by large ships such
as bunker fuel, or the spill of any oily refuse or waste oil.
• Cleanup and recovery from an oil spill is difficult and depends upon
many factors, including the type of oil spilled, the temperature of the
water (affecting evaporation and biodegradation), and the types of
shorelines and beaches involved.
• Spills may take weeks, months or even years to clean up.
• Crude oil and refined fuel spills from tanker ship
accidents have damaged natural ecosystems in Alaska
and many other places.
• The quantity of oil spilled during accidents has ranged
from a few hundred tons to several hundred thousand
• Smaller spills have already proven to have a great impact
on ecosystems, such as the Exxon Valdez oil spill
because of the remoteness of the site or the difficulty of
an emergency environmental response.
• Oil spills at sea are generally much more damaging than
those on land, since they can spread for hundreds of
nautical miles in a thin oil slick which can cover beaches
with a thin coating of oil.
GREATEST IN HISTORY
M/T Haven Tanker, 1991
Location: Genoa, Italy
Gallons: 42 million
How It Happened:
An apparently shoddily maintained tanker exploded and later sunk off the coast of
Italy. The accident killed six people.
Immediately after the incident, an effort by the Italians to tow the Haven to shore
failed, and the 820-foot-long (250 meter) vessel sunk off the coast of Genoa. Today it
is believed to be the largest shipwreck in the world and is a popular tourist
destination for divers.
Immediately after the incident Italian authorities scrambled to fight the fire and
control the spread of the spillage using six miles of inflatable barriers that were
submerged below the water surface around the vessel. The rest of the surface oil was
sucked up using vacuums.
Fergana Valley, 1992
Gallons: 87.7 million
How It Happened:
Nearly 88 million gallons of oil spilled from an oil well in Fergana Valley, one of
Uzbekistans’s most active energy- and oil-refining areas. While the spill didn’t get
much press at the time, it is the largest inland spill ever reported.
The ground absorbed this spill, leaving nothing for cleaning crews to tackle.
Nowruz Oil Field, 1983
Location: Persian Gulf
Gallons: 80 million
How It Happened:
Smack in the middle of the Iran-Iraq War, an oil tanker
crashed into the Nowruz Field Platform in the Persian Gulf
and knocked it askew, damaging the well underneath. The
oil well then leaked about 1500 barrels a day, but because it
was in the center of a war zone, seven months went by
before it was fixed.
Norpol, a Norwegian company, used booms and skimmers
to stem the spread of oil.
ABT Summer, 1991
Location: Off the coast of Angola
Gallons: 80 million
How It Happened:
While en route to Rotterdam, the fully loaded tanker ABT Summer experienced an
explosion onboard and caught fire while it was 900 miles off the coast of Angola,
leaking its payload into the ocean.
Surrounded by a growing oil slick that spanned 80 square miles, the tanker burned
for three days before sinking.
While no one can say how much of the oil sank or burned off, most of the oil is
thought to have been broken up by high seas at little environmental cost, thanks to
the incident’s offshore location.
Odyssey Oil Spill, 1988
Location: 700 nautical miles off the coast of Nova Scotia, Canada
Gallons: 43 million
How It Happened:
In November 1988 the Liberian tanker Odyssey, virtually full to the
brim with North Sea crude oil, broke in two and sunk in the North
Atlantic 700 miles off the coast of Nova Scotia. It also caught fire as it
Because the incident took place so far from the coastline, the oil was
expected to dissipate naturally, ergo no clean up at all.
and plant life
• Local industries effected include tourism as fishing,
swimming or sailing is made impossible in the event of an
• Industries that rely on fresh sea water also are effected
and cannot resume their activities till the water has been
• Fishing industry suffers majorly, not only because of the
large amount of marine life lost, but as the catch obtained
would be covered in oil and is hence inedible as they’re
• Furthermore, devices used to catch fish cannot be used for
fear of damaging them in area that have had an oil spill,
which means that boats can also not be used for the same
• The impacts are however short term and are remedied
once cleaning has been done, as fish reproduce in large
Effect on Human Health
• Inhalation of vapor, touching oil
slicks and consuming contaminated
• Exposure may cause neurological,
acute toxic effects, ocular (eye) and
also problems of respiratory system.
• People living in effected areas
showed nausea, throat infections,
nose and eye irritations etc along
with migraines and headaches.
• Ingestion of oil produces in sea food
is dangerous as oil products having
polycyclic aromatic hydrocarbons
(PAH). These are human
Effect on Marine Ecosystem
Factors on which it depends
Spread of oil slick
weather (cold , low
energy, little water
Proximity to bird
Area effected i.e.
Timing i.e. during bird
• Oil spills also have impacts on
• Oil reaching the root areas of plants
may be harmful
• However, a thick coating of oil on the
leaves does almost no damage if it
occurs outside the growing season.
• Loss of sea grasses and other vegetation
is harmful as these are food supplies
• Living coral is also vulnerable to oil
slicks. If the living coral dies, then the
reef of coral can be destroyed by wave
erosion. This means many fish and
animals lose their homes.
• Are salt tolerant tress and shrubs and provide
habitat for sea birds, crabs, oysters, breeding
ground for birds, Their complex root system
stabilizes and sediment, preventing soil erosion
• They are vulnerable to oil spills as they obtain
oxygen through lenticels on aerial roots, which
may become clogged and stop oxygen supply
• Toxic components in oil may also upset plants
mechanism of maintaining salt balance
• There may be long term loss of habitat
Categories of Marine Life Effected
Effect on Marine Life
• Oil, or hydrocarbons, can affect plants and animals in
• One of the most visually alarming physical effects on
marine birds and mammals is through smothering,
where oil coats the outside of their bodies, covering
feathers and fur.
• A less obvious impact is a toxic response to the oil.
• Toxic compounds from the spilt oil can be ingested by
animals directly, in their prey, as they breath or as they
clean their fur or feathers, causing short and long term
• These impacts can be difficult to quantify.
Spend more time on or near effected
Oil causes feathers to collapse and
matt. This may:
and change the insulation
properties of feathers and down.
This can severely hamper the ability
of birds to fly.
A breakdown in the water proofing
and thermal insulation provided by
the feathers, causing hypothermia.
seabirds lose buoyancy, sink and
drown because of increased weight
or lack of air trapped in the
Body weight decreases quickly as
the metabolism attempts to
counteract low body temperature.
Internal effects can include:
reduced reproduction ability,
reduction in the number of eggs laid,
decreased fertility of eggs,
decreased shell thickness and
disruption of the normal breeding and
• If oil spill occurs during breeding season,
effects are more drastic and this holds true for
all marine life
• These include sea otters, sea lions,
seals, walruses, sea cows (dugongs),
dolphins, porpoises and whales
• Marine mammals are vulnerable to
oil spills because of their
amphibious habits and their
dependence on air
• They show migratory behaviors
hence they show lesser impact due
to oil spills as compared to other
• The rough skin surface, body hair
and grooming habits of some
species increase the possibility of oil
contact, ingestion and associated
• The Exxon Valdez oil spill killed thousands of sea otters,
hundreds of harbor seals, roughly two dozen killer
whales and a dozen or more river otters. Even more
troubling in some ways, in the years after the Exxon
Valdez oil spill scientists noted higher death rates
among sea otters and some other species affected by
the oil spill, and stunted growth or other damage
among other species.
• Less effected due to reclusive
and migratory behavior
• They also have smooth
surfaces with little hair so
contact with oil by whales may
cause only minor oil
• Baleen whales, which skim the
surface are more likely to
ingest oil than "gulp feeders"
or toothed whales.
• Inhalation during surfacing
could damage mucous
membranes, damage airways
or even cause death.
• Spend much of their time on or near the surface
of the water, to breathe or haul our of sea
• Fur seals are more vulnerable as oil adheres to
fur, leading to reduced swimming ability and lack
of mobility out of the water.
• seal pups , mostly furry, are severely effected as
oil makes their flippers stick to their bodies,
leading to drowning or increased predation.
• Their mothers cannot identify them hence as
they cannot distingush them from their smell.
They may not feed it or it might even reject
attempts by the pup to suckle. This leads to
starvation and abandonment.
Long Term Impacts
• Oil sinks and can have damaging effects on fragile
underwater ecosystems, killing/ contaminating many fish
and smaller organisms that are essential links in the global
• Unbalanced Food Web - When oil spills happen around
breeding season, like the gulf oil disaster, egg and larval
populations are diminished or wiped out, effecting food
• Decreased Fish and Wildlife Populations -Herring
population collapsed 4 years after the 1989 Exxon Valdez
oil disaster that the herring population collapsed. Twenty
years later, it is still has not recovered.
• Decline in Recreation - Gulf states that relied on fishing and
recreation have been deprived of both from May to August,
and state park closures dealt a serious blow to tourism.
On The Beach
• Bioremediation The application of certain fertilizers to
beaches stimulates the growth of "oil-eating"
microbes. This fertilizing process is known as
• Hot Water & High Pressure By using hot water at high
pressure, cleanup crews blast oil off beaches into the
water where it can be skimmed off.
• Manual Treatment Manual treatment incorporates the
use of shovels, rakes, absorbent materials and human
• Mechanical Treatment Tractors loaders, and other
On The Water
• Boom comes in many sizes, shapes, and types and is
used primarily to deflect and/or collect oil
• Burning Fresh oil contains gases which are very
volatile. By igniting these gases whole oil slicks can be
reduced to tarry residue.
• Dispersants are used to do just that, disperse. They are
chemicals that break-up oil into smaller and smaller
concentrations. Potentially into individual molecules
• Skimming is a mechanical system for removing oil from
the surface. This process was created based on the
reality that oil is lighter than water.
BOOMS are First Used to
Contain the Oil Spill
Photo by EPA
Containment booms control the spread of oil
to reduce the possibility of polluting
shorelines and other resources,
concentrate oil in thicker surface layers,
divert and channel oil.
Booms are anchored to tied to buoys
Need to be monitored for changes for tides
and shifts in waves.
Wood pipes, plastics, tyres ,etc. inflated
• An above-water "freeboard" to contain the oil and to
help prevent waves from splashing oil over the top of
• A flotation device
• A below-water "skirt" to contain the oil and help
reduce the amount of oil lost under the boom
• A "longitudinal support," usually a chain or cable
running along the bottom of the skirt, that strengthens
the boom against wind and wave action; the support
may also serve as a weight or ballast to add stability
and help keep the boom upright
In situ BURNING
• the process of burning oil slicks at sea, at or close
to the site of a spill.
• removes large amounts of oil from the sea
• there are a number of problems which limit the
viability of this response technique.
• the ignition of the oil; maintaining combustion of
the slick; the generation of large quantities of
smoke; the formation and possible sinking of
extremely viscous and dense residues; and safety
• Helitorch is a flame-thrower which is suspended beneath a
helicopter and is generally accepted as being one of the
safest methods of ignition in trained hands.
• Fire proof containment boom and an igniter will most
probably be required for a burn to be undertaken.
• Issues such as the distance of the oil from the damaged
vessel or from a populated area; the potential toxicity of
the resultant smoke; the nature of the oil.
• The viscous residue that can be left following in-situ
burning resembles the consistency of toffee,
• it is difficult to recover both at sea and from the shoreline.
• Sunken residue has the potential to smother or poison
bottom dwelling (benthic) species.
• In the response to the spill from the HONAM JADE (South
Korea, 1983) crude oil was deliberately ignited. As a result,
a dense residue formed which sank and seriously
contaminated shell fish beds. When oil does sink to the sea
bed and cause problems, the scope for recovering it is
• A skimmer is a device for recovering spilled oil from the
• Skimmers may be self-propelled, used from shore, or
operated from vessels.
• The efficiency of skimmers depends upon conditions at sea.
Oleophilic skimmers use belts, disks, or continuous mop chains
of Oleophilic materials to blot the oil from the water surface.
The oil is then squeezed out or scraped off into a recovery
tank. Can be used effectively on spills of any thickness.
Suction skimmers operate similarly to a household vacuum
cleaner. Oil is sucked up through wide floating heads and
pumped into storage tanks.
• Sorbents are insoluble materials or mixtures of
materials used to recover liquids through the
mechanism of absorption, or adsorption, or both.
• To be useful in combating oil spills, sorbents need to be
both Oleophilic (oil-attracting) and hydrophobic
• They are as the sole cleanup method in small spills.
• sorbents are most often used to remove final traces of
oil, or in areas that cannot be reached by skimmers.
• Sorbent used to recover oil must be disposed of in
accordance with approved local laws . Any oil that is
removed from sorbent materials must also be properly
disposed of or recycled.
• include peat
moss, straw, hay,
3 and 15 times
their weight in
• consist of clay,
wool, sand, or
from 4 to 20
weight in oil.
absorb up 70
times their own
weight in oil.
• Gelling agents, aka solidifiers, are chemicals that react with oil
to form rubber-like solids.
• With small spills, they are applied by hand and left to mix on
• For treating larger spills, the chemicals are applied to the oil,
then mixed in by the force of high-pressure water streams. The
gelled oil is removed from the water using nets, suction
equipment, or skimmers, and is sometimes reused after being
mixed with fuel oil.
• Gelling agents can be used in calm to moderately rough seas.
• Drawback is that Large quantities of the material must often be
applied, as much as 3X the volume of the spill. For oil spills of
millions of gallons it is impractical.
• Dispersants are chemical solvents or
• They don't eliminate oil, they make it less
obvious by breaking it into small pieces which
spread throughout the ocean.
• The dispersant Corexit is being used by BP and
has been proven to be toxic to
microorganisms and fish eggs.
Presented by : Shaima Saqib
• Bioremediation is a waste management technique
that involves the use of organisms to remove or
neutralize pollutants from a contaminated site.
• Technologies can be generally classified as in
situ or ex situ.
• In situ bioremediation involves treating the
contaminated material at the site, while ex
situ involves the removal of the contaminated
material to be treated elsewhere.
• Some examples of bioremediation related
are phytoremediation, bioventing, bioleaching, landfa
rming, bioreactor, composting, bioaugmentation.
• Bioremediation may occur on its own (natural
attenuation or intrinsic bioremediation) or may
only effectively occur through the addition of
fertilizers, oxygen, etc., that help encourage the
growth of the pollution-eating microbes within
• Recent advancements have also proven
successful via the addition of matched microbe
strains to the medium to enhance the resident
microbe population's ability to break down
The Biological and Chemical
Processes of Bioremediation
• Many microorganisms possess the enzymatic capability to
degrade petroleum hydrocarbons.
• Some microorganisms degrade alkanes, others aromatics,
and others both paraffinic and aromatic hydrocarbons
• More complex structures are more resistant to
biodegradation, meaning that fewer microorganisms can
degrade those structures and the rates of biodegradation are
lower than biodegradation rates of the simpler hydrocarbon
structures found in petroleum. The greater the complexity of
the hydrocarbon structure, i.e., the higher the number of
methyl branched substituents or condensed aromatic rings,
the slower the rates of degradation
•The biodegradation of petroleum in the marine environment
is carried out largely by diverse bacterial populations,
including various Pseudomonas species.
• The hydrocarbon-biodegrading populations are widely
distributed in the world’s oceans; surveys of marine
bacteria indicate that hydrocarbon-degrading
microorganisms are ubiquitously distributed in the marine
• Generally, in pristine environments, the hydrocarbondegrading bacteria comprise < 1% of the total bacterial
• These bacteria presumably utilize hydrocarbons that are
naturally produced by plants, algae, and other living
organisms. They also utilize other substrates, such as
carbohydrates and proteins.
• When an environment is contaminated with
petroleum, the proportion of hydrocarbondegrading microorganisms increases rapidly. In
particular, in marine environments
contaminated with hydrocarbons, there is an
increase in the proportion of bacterial
populations with plasmids containing genes
for hydrocarbon utilization.
Need for Bioremediation
It is particularly important to address oil polluted waters
as soon as possible as the contamination can have the potential
to damage fishery resources and affect the health of those
animals and humans that consume contaminated fish .
Besides the varying rates of biodegradation, researchers
have consistently documented a lag time after oil is spilled
before indigenous microbes begin to break down the oil
• This lag time is related to the initial toxicity of the volatile
fractions of the oil, which evaporate in the first few days of a
spill. Microbial populations must begin to use oil and expand
their population before measurable degradation takes place, a
period usually lasting several days. This fact becomes very
important when considering the appropriateness of
bioremediation as a quick or first response technique
Seeding with Microbial Cultures
One approach often considered for the
bioremediation of petroleum pollutants after an oil
spill is the addition of microorganisms (seeding) that
are able to degrade hydrocarbons. Most
microorganisms considered for seeding are obtained
by enrichment cultures from previously
• However, because hydrocarbon-degrading bacteria
and fungi are widely distributed in marine,
freshwater and soil habitats, adding seed cultures has
proven less promising for treating oil spills than
adding fertilizers and ensuring adequate aeration
• Hydrocarbon biodegradation in marine environments is often limited
by abiotic environmental factors such as molecular oxygen,
phosphate and nitrogen (ammonium, nitrate and organic nitrogen)
• Rates of petroleum biodegradation are negligible in anaerobic
sediments because molecular oxygen is required by most
microorganisms for the initial step in hydrocarbon metabolism.
Oxygen, however, is not limiting in well aerated (high energy) marine
• Usually, marine waters have very low concentrations of nitrogen,
phosphorus and various mineral nutrients that are needed for the
incorporation into cellular biomass, and the availability of these
within the area of hydrocarbon degradation is critical.
• Secondary containment :
methods to prevent releases of oil or hydrocarbons
• Oil Spill Prevention Containment and
Countermeasures (SPCC) program by the United
States Environmental Protection Agency.
• Double-hulling :
build double hulls into vessels, which reduces the
risk and severity of a spill in case of a collision or
grounding. Existing single-hull vessels can also be
rebuilt to have a double hull.
• Thick-hulled railroad transport tanks
• The Environmental Sensitivity Index (ESI),
developed by RPI’s senior scientists in 1976,
has become an integral component of oil-spill
contingency planning , response and coastal
resource management in the USA and other
• Environmental Sensitivity Index (ESI) maps are
used to identify sensitive shoreline resources
prior to an oil spill event in order to set
priorities for protection and plan cleanup
strategies. By planning spill response ahead of
time, the impact on the environment can be
minimized or prevented.
Environmental sensitivity index maps
are basically made up of information
within the following three categories:
• Ranked according to a scale relating to sensitivity,
natural persistence of oil, and ease of cleanup.
The sensitivity ranking is controlled by the
1) Relative exposure to wave and tidal energy;
2) Shoreline slope;
3) Substrate type (grain size, mobility, penetration,
and traffic ability); and
4) Biological productivity and sensitivity.
• Including oil-sensitive animals and rare plants; and habitats, which are used
by oil-sensitive species or are themselves sensitive to oil spills, such as
submersed aquatic vegetation and coral reefs.
• Biological resource information collected and used in ESI maps can also be
used for coastal resource management. The type of data collected for the
biological resources are:
1) Large numbers of individuals are concentrated in a relatively small area;
2) Marine or aquatic species present during special life stages or activities,
such as nesting, birthing, resting, or molting;
3) Early life stages or important reproductive activities occur in somewhat
4) Restricted areas important to specific life stages or migration patterns;
5) Specific areas are known to be vital sources for seed or propagation;
6) The species are threatened, endangered, or rare; or
7) A significant percentage of threatened/endangered species are likely to
• Specific areas that have added sensitivity and
value because of their use, such as:
1) High-use recreational and shoreline access
locations (i.e. beaches, parks, boat ramps, etc.);
2) Management areas (i.e. refuges, preserves,
3) Resource extraction locations (i.e. water intakes,
aquaculture/lease sites, etc.); and
4) Archaeological, Historical, and Cultural resource