Oil spill: Potential Global Environmental hazard to
Earth’s biosphere
As the world struggles with a health emergency in the
wake of Covid-19, a small island nation of Mauritius has declared
an environment emergency after a grounded vessel began leaking tonnes of oil
into the Indian Ocean. A Japanese oil tanker, The MV Wakashio vessel,
reported to be carrying nearly 4000 tonnes of oil, ran aground on a coral reef
on Mauritius’s southeast coast on 25 July, 2020. According to media reports, more than 1000
tonnes of fuel have leaked from the cracked vessel into the ocean – polluting
the nearby coral reefs, as well as the surrounding beaches and lagoons.
An environmental emergency is defined as a "sudden-onset
disaster or accident resulting from natural, technological or human-induced
factors, or a combination of these, that causes or threatens to cause severe
environmental damage as well as loss of human lives and property.
Following a disaster or conflict, an environmental
emergency can occur when people's health and livelihoods are at risk due to the
release of hazardous and noxious substances, or because of significant damage
to the ecosystem. Examples include fires, oil spills, chemical accidents, toxic waste dumping and groundwater pollution. However, oil spills are, particularly, taking a heavy
toll of immediate marine environment during the recent years and the
environmental risks can be acute and life-threatening. All such disasters have
some environmental impacts. Some of these may be immediate and life-threatening
– for example, when an earthquake damages an industrial facility, which in turn
releases hazardous materials. In such cases these so-called 'secondary impacts'
may cause as much damage as the initial causal factor. For example, Typhoon
Haiyan/Yolanda that struck the Philippines in November 2013, caused massive
destruction and had a huge human toll but also generated a spill of around
800,000 litres of heavy oil, when a power barge ran aground in Estancia, Iloilo
province, at the height of the typhoon.
How do oil spills occur? Oil spills that happen in rivers, bays and
the ocean most often are caused by accidents involving tankers, barges,
pipelines, refineries, drilling rigs and storage facilities, but also occur
from recreational boats and in marinas.
Spills can be caused by:
· people making mistakes or being careless
· equipment breaking down
· natural disasters such as hurricanes, storm
surge or high winds
· deliberate acts by terrorists, acts of war,
vandals or illegal dumping.
Most oils float on the oceans’ saltwater or
freshwater from rivers and lakes. Oil usually spreads out rapidly across the
water’s surface to form a thin oil slick. As the oil continues spreading, the
slick becomes thinner and thinner, finally becoming a very thin sheen, which
often looks like a rainbow. However, in rare cases, very heavy oil can
sometimes sink.
An oil-spill is
the release of a liquid petroleum hydrocarbon into
the environment, especially the marine ecosystem, due to human activity, and is
a form of pollution.
The term is usually given 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 (such as gasoline, diesel)
and their by-products, heavier fuels used by large ships such as bunker fuel,
or the spill of any oily refuse or waste oil.
Oil
spills penetrate into the structure of the plumage of
birds and the fur of
mammals, reducing its insulating ability, and making them more vulnerable to
temperature fluctuations and much less buoyant in
the water. 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. Oil
spills can have disastrous consequences for society; economically,
environmentally, and socially. As a result, oil spill accidents have initiated
intense media attention and political uproar, bringing many together in a
political struggle concerning government response to oil spills and what
actions can best prevent them from happening.
Environmental pollution caused by petroleum is of
great concern. This is because petroleum hydrocarbons are toxic to all forms of
life and harm both aquatic and terrestrial ecosystems. Why the pollution of
marine habitats has caught the attention of researchers and environmentalists today?
I think this is due to the serious impact of oil spills on marine life, as well
as on people whose career relies on the exploitation of the sea’s resources.
Additionally, marine life may be affected by clean-up operations. It may also
be indirectly affected by the physical damage to the habitats in which plants
and animals live in. Petroleum marine fuel spills, which result from damage,
transportation accidents and various other industrial and mining activities,
are classified as hazardous waste. They are considered to be the most frequent
organic pollutants of aquatic ecosystems. In recent years, there have been
numerous studies regarding the levels of contamination of the seawater by
hydrocarbons. The majority of these studies were conducted following the Gulf
War of 1991 and after, the BP Deepwater Horizon (DWH) oil spill on 20th April,
2010. Petroleum contamination is a growing environmental concern that harms
both terrestrial and aquatic ecosystems. However, the public and regulatory and
scientific communities have given more attention to the contamination of marine
habitats. This is because marine oil spills can have a serious economic impact
on coastal activities, as well as on those who exploit the resources of the
sea. Thus, communities that are at risk of oil disasters must anticipate the
consequences and prepare for them.
Crude
oil and refined fuel spills from tanker ship accidents
have damaged vulnerable ecosystems in Alaska,
the Gulf of
Mexico, the Galapagos Islands, France,
the Sundarbans,
Ogoniland, and many other places. The quantity of oil spilled during accidents
has ranged from a few hundred tons to several hundred thousand tons
(e.g., Deepwater
Horizon Oil
Spill, Atlantic Empress, Amoco Cadiz), but
volume is a limited measure of damage or impact. 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. Since 2004, between 300 and 700 barrels of oil per day have been
leaking from the site of an oil-production platform 12 miles off the Louisiana coast
which sank in the aftermath of Hurricane Ivan.
The oil spill, which officials estimate could continue throughout the 21st
century, will eventually overtake the 2010 BP Deepwater Horizion
disaster as the largest ever, but there are currently no efforts to cap the
many leaking well heads. The largest oil spill in all categories, however, was
a war-related incident. During the Gulf War, in Kuwait in 1991, in anticipation
of a landing by the US Marines from the sea, much like D-Day during World War
II, the Iraqis emptied all the oil-storage tanks along the coast, the strategy
being to set fire to the oil when the enemy came, roasting them in the flames.
The enemy didn’t come, not that way, and the war took a totally different turn.
Left in the Persian Gulf was 1200 000 tons of intentionally discharged oil. The
contamination was, obviously, massive but the damage, as far as it could be
assessed under the circumstances, only moderate. Even local coral reefs,
sometimes referred to as ‘seasonal’ as they appear dormant during the part of
the year with highest temperature and salinity, were not severely affected,
perhaps because they were hit during their inactive period. Evaporation of
volatile oil fractions, photo-oxidation, and general weathering progressed
rapidly at the high temperatures and in the calm shallow waters of the Gulf.
How do oil spills affect the marine environment? Impact of oil spills on marine organisms depends on
the fate of the oil. When oil is present in the environment, it is either
dispersed in the top layer of the water (littoral zone) or remains on the
surface and, consequently, on the coastal areas. If the oil is not dispersed,
it remains on the surface. In this case, currents bring the oil towards coastal
areas which harms coastal organisms like invertebrates, mammals and birds.
However, if the oil is dispersed, organisms, such as fish, plankton and larvae,
are immediately subjected to oil toxicity. Zooplankton is a particularly
important food resource, especially for baleen whales. It can influence or
control the primary productivity by top-down effects in return. Its population
dynamic change can influence the biomass of other marine animals like fish by
bottom-up effects. Some zooplankton, such as copepods, euphausiids and mysids,
assimilate hydrocarbons directly from seawater and by ingesting oil droplets
and oil contaminated food. The ingestion of oil by these organisms often causes
mortality, while surviving organisms often show developmental and reproductive
abnormalities.
Oil dispersants are potentially harmful to
marine life including coral reefs also. In a study using coral nubbins
in coral reef eco-toxicology testing, found that dispersed oil and oil
dispersants are harmful to soft and hard coral species at early life stages. In
addition, recreational attractions for divers, coral reefs are
considered to be important constituents of marine ecosystems. This is because
they are important nurseries for shrimp, fish and other animals. The aquatic
organisms that live within and around the coral reefs are at risk of exposure
to the toxic substances within oil, as well as smothering. They are rapidly
deteriorating because of a variety of environmental and anthropogenic pressures.
Thus, they are suffering significant changes in diversity, species abundance
and habitat structure worldwide. Depending on the
circumstances, oil spills can be very harmful to marine birds, sea turtles and mammals, and also
can harm fish and shellfish. Oil destroys the insulating ability of fur-bearing
mammals, such as sea otters, and the water-repelling abilities of a bird's
feathers, exposing them to the harsh elements. Many birds and animals also
swallow oil and are poisoned when they try to clean themselves or when eating
oiled prey. Fish and shellfish can also digest oil, which could cause changes
in reproduction, growth rates or even death. Commercially important species
such as oysters, shrimp, mahi-mahi, grouper, swordfish and tuna also could
suffer population declines or become too contaminated to be safely caught and
eaten. Depending on just where and when a spill happens, from a few up to
hundreds or thousands of birds, fish, mammals, reptiles, corals and other
animals and plants can be killed or injured. 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. These can kill seabirds, mammals,
shellfish and other organisms they coat. Oil spills on land are more readily
containable if a makeshift earth dam can be rapidly bulldozed around
the spill site before most of the oil escapes, and land animals can avoid the
oil more easily. Since most oils float, the
creatures most affected by oil are animals like sea otters, turtles and seabirds that
are found on the sea surface or on shorelines if the oil comes ashore. During
most oils pills, seabirds are harmed and killed in greater
numbers than other kinds of creatures In general, spilled oil can affect
animals and plants in two ways: dirесt from the oil and from the response or
cleanup process. There is no clear relationship between the amount of oil
in the aquatic environment and the likely impact on biodiversity. A smaller
spill at the wrong time/wrong season and in a sensitive environment may prove
much more harmful than a larger spill at another time of the year in another or
even the same environment. Oil penetrates into the structure of the plumage of
birds and the fur of
mammals, reducing their insulating ability, and making them more vulnerable to
temperature fluctuations and much less buoyant in
the water.
Effects
of oil spills on wild life and its impact on human life is huge and cannot be
ignored. Oil-drenched seabirds have become
the prevailing image of the effects of oil spills, with the chemicals released
by oil spills having the ability to disrupt their bodily functions to such an
extent that killing oil-soaked birds would be kinder than cleaning them. Oil
spills can coat the feathers of birds, making flying impossible and removing
the natural insulation and waterproofing the feathers provide. This leaves the
birds susceptible to hypothermia or overheating. Attempts to remove the oil
through preening also causes birds to swallow oil, which causes severe organ
damage. Migratory patterns and nesting grounds can be contaminated by oil
spills, with potentially disastrous effects on natural life cycles of many
species of bird. Mammals are also vulnerable to the effects of oil spills. Much
like with birds, oil can coat the insulated fur of marine mammals and leave
them open to overheating or hypothermia.
The
effects of oil spills on wildlife can in turn adversely affect humans too. For
instance, the contamination of local ecosystems can impact communities who rely
on said ecosystems to survive, with crops and food sources becoming poisonous
or disappearing altogether as a result of food chains being de-stabilized.
Water supplies in surrounding areas are at risk of contamination from oil
spills. In 2013, oil spills interrupted the supply of water for 300,000
people in Miri, Malaysia and 80,000 people in
Coca, Ecuador. Fishermen and local ship workers can lose their sources of
income due to the health problems associated with exposure to oil such as
respiratory damage, decreased immunity and increased cancer risk. This could
deprive communities of essential resources and revenue needed to support them. Oil
spills can affect the air quality in surrounding areas,
releasing toxic chemicals into the atmosphere. Following the 2010 Deepwater
Horizon disaster, a 2015 study found concentrations of
benzene and fine particulate matter around southeast Louisiana that were high
enough to exceed public health criteria, with measurable exposure disparities
in the coastal areas closer to the spill and clean-up activities. A 2019
study in Nigeria, Africa’s most populous country and largest oil
producer, discovered that nearby oil spills increased neonatal mortality by
38.3% per 1,000 live births. Further evidence suggesting these effects persist
for several years after an oil spill takes place, with the study describing the
impact as “an alarming ongoing human tragedy.
Oil spills can do a lot of harm to animals because oil
spills mainly occur in the ocean. It is important that
we, human beings, also should avoid oil spills because they could
also do a lot of harm to us, the humans. According to the International
Disaster Database (EM-DAT),
between 2003 and 2013, there were 380 industrial accidents reported, affecting
207 668 people and resulting in over US$22 million in losses. Climate change is
having an unprecedented effect on the occurrence of natural disasters and the
associated risk of environmental emergencies. With climate change already
stretching the disaster relief system, future climate-related emergency events
will generate increased and more costly demands for assistance. Disasters may
also have longer-term impacts. For example, natural disasters may cause
long-term waste management difficulties or eco-system damage.
The Environmental Emergency Program (EEP) is
responsible for responding to hazardous material spills. The program
develops and implements tools to prepare for, respond to and recover from spill
incidents and other environmental emergencies. EEP is dedicated to
protecting the welfare of the public and environment in the event of an
environmental emergency or disaster. Therefore, controlling oil slicks is critical to protecting
sensitive areas of environment. Approaches and techniques vary by need. The response to an oil spill has several goals – foremost to stop
the flow of the oil or chemical, but also to protect sensitive areas that could
be harmed by the spill itself, and to safely remove the oil from the
environment as quickly and efficiently as possible.
During a spill response, sensitive locations, like coastal
wetlands or animal nesting areas threatened by an oil slick, can be protected
with various kinds of equipment and tactics, but the tools used depend on where
spill has occurred and type of oil spilled. Some spills evaporate rapidly off
the water surface without any active clean-up needed. Booms are floating physical barriers, made of plastic, metal or other
materials, which slow the spread of oil and keep it contained. This method is
presently being used to contain the Mauritius oil spill. A boom may be placed
around a tanker that is leaking oil, to collect the oil, or along a sensitive
coastal area to prevent oil from reaching it. Another
approach—dependent in part on the thickness of the slick—is to contain and
remove oil through skimmers, boats and other devices that can remove oil from
the sea surface before it reaches sensitive areas. They skim or scoop oil from
the water surface so it can be collected for proper disposal. Arguably, other possible, but more controversial and
rarely used measures include:
·
In situ burning, a method of burning freshly spilled oil, usually while it's
floating on the water.
·
Using aircraft or boats to apply dispersants (chemicals that disperse the oil into the water column) so that much
less stays at the surface where it could move to coastal wetlands, beaches, and
tidal flats endangering critical habitat and nursery areas
·
Responders can use biological agents such as microbes or fertilizers to help break down oil into its chemical constituents.
·
Responding to shoreline oil spills :
1. Shore-line flushing/washing
2. Booms
3. Vacuums
4. Absorbents
5. Shoreline cleaners and bio-degradation agents
6. Burning
7. Manual removal
8. Mechanical removal
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