Home' Trinidad and Tobago Guardian : June 7th 2017 Contents tobagotoday.co.tt June 7 - 2017
Oil spills are "bad for the environment". Ideally, there
should be no oil spills once all measures are put in place
to prevent such occurrences. Unfortunately, accidents do
happen and oil spills negatively impact plants, animals
and humans, but an "ounce of prevention is better than
a pound of cure". The severity of the impact depends on
factors such as the type of oil, location of the spill, the
level and route of exposure.
WHAT IS THE COMPOSITION OF OIL?
Crude oil is a mixture of thousands of compounds com-
prising largely of atoms of carbon and hydrocarbon, hence
the name - hydrocarbons. It has smaller amounts of
nitrogen, sulfur and oxygen and some trace metals such as
iron, nickel and vanadium. Most often the oils that neg-
atively impact our environment are petroleum-based com-
pounds as opposed to non-petroleum based oils such as
coconut, olive and shark oils. Coconut oil and olive oil are
of plant origin while whale oil and fish liver oil are of
animal origin and are relatively non-toxic. The petro-
leum-based oils that are of environmental concern are
crude petroleum and its refined products such as gasoline,
kerosene, diesel oils and lubricating oils. Spillages of these
types of oils present a risk to terrestrial and aquatic life.
WHAT IS THE TOXIC FRACTION OF OIL?
Most scientific studies indicate that the aromatic and
polycyclic aromatic (PAHs) fractions of oil are responsible
for its toxic nature. Benzene compounds are an example
of aromatic compounds in crude and refined oils that are
classed as "carcinogens" since they are linked to causing
cancer. PAHs consist of more than one benzene ring fused
together. Examples of PAHs are naphthalene, chrysene and
benzo(a)pyrene compounds. Benzo(a)pyrene has been exten-
sively studied and rated as the most toxic PAHs, given a
toxic equivalency factor (TEF) of unity, whereby all other
PAHs are compared to it.
Light vs Heavy Oils and the impact on the environment
Light oils such as gasoline and diesel that are used in
cars and trucks are very volatile which means that the
majority of it is lost in the environment after the spill.
However, the major concern is the immediate risk of a fire
and explosion, and the inhalation of toxic vapors at the
spill site. Light oil will spread out quickly and dissolve in
the aquatic environment and may cause immediate death
to organisms depending on the size of the spill, but will
not be persistent (long lasting). On the other hand, heavy
oils such as bunker "C" and crude oils will degrade slow-
ly in the environment and last weeks or months depending
on the amount spilled, the location and prevailing weath-
er conditions. Toxic compounds in heavy oils can be per-
sistent in the environment until the compounds are degrad-
ed, and transformed by microbial degradation to less toxic
HOW OIL MAY AFFECT ANIMALS AND PLANTS?
The acute or "short-term" effects of oil is the smoth-
ering of animals and plants. This can lead to impairment,
and ultimate death depending on the severity of the spill
including the size of the spill, amount, location, time of
year and prevailing weather conditions. The habitats of
marine organisms would also be disrupted. Areas vulner-
able to oil spills include nursery sites, coral reefs, estuarine
areas and enclosed bays in which dispersion and flushing
of oil may be low, coupled with high pollutant persistence
and build up. In the open ocean, there may be better mix-
ing and dilution and avoidance by aquatic organisms.
Chronic or "long term" exposure can lead to habitat loss,
tainting of shellfish and finfish, reproductive impairment,
reduced species diversity and abundance. Bio-accumulation
of PAHs in the food chains can occur as smaller aquatic
organisms in oil contaminated sites are eaten by larger
organisms such as fish. As the oil floats, seabirds may be
covered and may die from hypothermia (they lose the
ability to keep themselves warm). Sea turtles and other
mammals can mistakenly eat oiled substances such as tar
balls for food, and this could lead to death.
HOW IS HUMAN HEALTH AFFECTED BY OIL SPILLS?
Precautionary measures should be taken by humans
during an oil spill so as to limit exposure to the toxic
compounds. The route of exposure can be by direct inha-
lation, skin contact and eating of contaminated food. Direct
inhalation of volatile fumes after a spill can lead to irrita-
tion of the nose, throat and lungs, headaches, nausea,
dizziness, fatigue, loss of coordination and labored breath-
ing. According to the United States Centers for Disease
Control and Prevention, long term exposure can lead to
neurological effects on the central nervous system causing
depression, damage to blood and organs such kidneys.
There is also a significant increase in the risk of cancer.
Extremely vulnerable groups are children and pregnant
What can you do to limit exposure after an oil spill?
• Avoid contaminated areas.
• Avoid bathing in contaminated waters.
• Wear protective clothing (coveralls, respiratory organ-
ic fumes mask, and safety boots) during oil spill clean-
• Warn people of contaminated areas, and avoid eating
fish captured in areas subject to an oil spill.
Dr. Darryl Banjoo
Senior Research Officer
Institute of Marine Affairs
Impacts on the marine environment and human health
Oil spills negatively impact animals,
plants and human health. Contaminated
areas should be avoided and cleaned up
as soon as possible.
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