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International Journal of Agricultural Sciences and Natural
International Journal of Agricultural Sciences and NaturalInternational Journal of Agricultural Sciences and Natural
International Journal of Agricultural Sciences and Natural
Resources
ResourcesResources
Resources
2014; 1(4): 76-80
Published online September 30, 2014 (http://www.aascit.org/journal/ijasnr)
Keywords
Ecological Effects,
Oil exploration,
Niger-Delta,
Sustainable Development,
Nigeria
Received: September 17, 2014
Revised: September 25, 2014
Accepted: September 26, 2014
Review of ecological effects of oil
exploration in the Niger-Delta,
Nigeria
Emmanuel Teryila Tyokumbur
Ecology and Environmental Biology Unit, Department of Zoology, University of Ibadan, Ibadan,
Nigeria
Email address
e.tyokumbur@mail.ui.edu.ng
Citation
Emmanuel Teryila Tyokumbur. Review of Ecological Effects of Oil Exploration in the
Niger-Delta, Nigeria. International Journal of Agricultural Sciences and Natural Resources.
Vol. 1, No. 4, 2014, pp. 76-80.
Abstract
A review was carried out on the ecological effects of oil exploration in the Niger-Delta
region of Nigeria. The Niger-Delta is a vast bird foot-shaped floodplain and the World’s
third largest delta. It is a geographical entity situated in the central part of Southern-
Nigeria that is home to the oil-producing states of Nigeria. Oil activities and its
ecological effects are discussed with remediation of affected sites. Sustainable
development is recommended in the sector to boost the economy and meet the
environmental quality aspirations of host communities.
1. Introduction
The Niger Delta Area is located in the South-South region of Nigeria, with a total area
of 7,722.04 square miles, and located between 4
o
15
1
N and 4
o
50
1
N and 5
o
25
1
E and
7
o
37
1
E (Powell et al., 1985). The population of the area is about 31 million (CRS, 2008),
(Akintola, 1982).The accumulation of marine sediment buildup and fluviatile activities
during the upper Cretaceous, led to the formation of the Niger Delta, which is typified by
widespread interconnectivity of deltaic tributaries, mangrove swamps, flood plains,
creeks, and coastal barrier islands. The soils is of fluvial origin, characteristic of the
back-swamps soils include peat covered water-logged weighty clay whereas clay and
silty loamy soils found in elevated areas (Rahaman, 1976).The region is home to the oil-
producing states of Nigeria namely Abia, Akwa Ibom, Bayelsa, Cross-River, Delta, Edo,
Imo, Ondo and Rivers (Nwokolo, 2001). The oil-rich area is home to Nigeria’s vast
crude oil reserves, which stands at nearly 40 billion barrels excluding its enormous
natural gas reserves, which is estimated at approximately 100 trillion cubic feet (Abulu,
2001). The Niger Delta is the world’s largest mangrove forest, West Africa’s most
extensive freshwater swamp forest, Nigeria’s last remaining rainforests and one of the
continent’s remaining sanctuaries of unique wildlife (Onosode, 2001).It is indeed a
region of vast human and natural resources.
1.1. Brief History of Oil Exploration Activities in the Niger-Delta
Oil exploration activities in the Niger-Delta dates back to the first decade of the 20
th
century when a German Oil Company prospecting for bitumen in the coastal parts of
Ayetoro in present day Ondo State started. The company made little progress until World
War I started. They did not return after the war. In 1937, the Shell d’Arcy Company
(present day Shell Petroleum Development Company) started further activities in the
Okigwe-Owerri-Aba-Port Harcourt axis of Eastern Nigeria. The first commercial oil
77 Emmanuel Teryila Tyokumbur: Review of Ecological Effects of Oil Exploration in the Niger-Delta, Nigeria
production and export eventually were from the oil fields of
Oloibiri in today’s Bayelsa State.
Beginning with a daily production rate of just 5,100 barrels
of oil per day (bopd) in 1958, production rose steadily such
that by independence (1960), the export level of 17,000 bopd
had already been reached. Over the years after independence
and the Nigerian Civil War, production rose to over 2.0
million bopd. This was mainly as a result of the impressive
global demand and upbeat price situation culminating in the
oil boom, which started in 1973. Production today averages
2.2million bopd, but actual figures now depend on many
internal and external factors, including Organization of
Petroleum Exporting Countries (OPEC) quotas. Oil
production is predicted to grow faster over the successive
years with other companies like Chevron, Mobil Producing,
Texaco Nigeria, Agip Oil, Elf Petroleum, Conoil, Sun Oil and
Oando amongst others joining the league of oil companies
involved in crude oil exploration in the Niger-Delta.
1.2. Reserve Base and Production in the
Region
In 1959, the crude oil reserve base of the country was a
modest 25 million barrels. In 2006, it was estimated to stand
at nearly 35 million barrels with the government targeting 50
million barrels in subsequent years. Exploration and
production activities are mainly concentrated in the onshore
and offshore parts of the Niger-Delta region. Although
substantial funds have been committed over the years into the
prospecting for oil and gas in the Upper Benue and Chad
Basin areas of the country, commercial quantity has not been
struck in these areas. Many deepwater offshore fields
recently discovered are expected to come on stream in the
years ahead (Onuoha, 2004).Apart from crude oil, Nigeria
also has vast reserves of natural gas in the Niger-Delta. For
every cubic metre of oil extracted, there is an equivalent of
187 cubic metres of natural gas. These vast reserves make
Nigeria the 3
rd
most productive nation among OPEC
countries, while ranking ninth on the global scale with
approximately 2.8% of world production (Jones, 1998).
Crude oil production in Nigeria averaged 2.332 million
barrels of oil per day (bopd) in 1997. The average for 1998
and 1999 were 2.13 and 2.153 million bopd. The OPEC
quotas were mainly accountable for production cuts in 1999
to 1.89 million bopd but which was hiked to 2.2 million
barrels in 2004. Oil forms the mainstay of the Nigerian
economy with the sector providing Nigeria with 90% of her
foreign exchange earnings, 80% of her gross domestic
product (GDP) and 96% of the National Budget. Some oil
producing states have their internal revenues solely generated
from derivations from the oil trade.
However, the Niger-Delta from which the oil is obtained
suffers environmental degradation due to the oil exploration
activities. These activities creates harmful effects on the
components of the environment namely air, water, soil and
living organisms. Humans as well as domestic animals are
affected by the prospecting, exploration and exploitation of
crude oil and associated gas.
1.3. Oil activities in the Niger-Delta
The oil industry in Nigeria is mainly confined to the
onshore and offshore parts of the Niger-Delta. The industry is
usually considered to be in two distinct classes:
1.3.1. The Upstream Sector
The upstream sector refers to activities in oil exploration
and production that are carried out within or around the oil
wells. These activities include prospecting (searching for oil
deposits in commercial quantities), production (actual
pumping of the discovered oil out of the Earth) and
transportation (moving the unrefined crude oil to the
refineries).
1.3.2. The Downstream Sector
The downstream sector of the oil industry involves the
refining of crude oil into various products like petrol, diesel,
kerosene, naphtha (to mention a few) and the transportation
of refined products to consumers by pipelines, sea, road,
tankers and rail tankers.
Activities in these sectors (upstream and downstream)
have adverse effects on the flora and fauna of these oil-rich
areas. These negative effects and their remediation form the
basis of this review.
2. Effects of Oil Activities on the
Environment
2.1. Oil Pollution
According to the World Health Organization, the
environment is considered to be polluted when it is altered in
composition or conditions directly or indirectly as a result of
the activities of man so that it becomes less suitable to some
or all of the uses for which it would be suitable in its natural
state. Activities in the oil industry exposes the entire
community to ever increasing environmental contaminants,
which leads to pollution of air, land and water thereby
rendering them unsafe for human use (Fekumo, 2004).
The disastrous effects of oil pollution on the environment
have been proved beyond reasonable doubt. It has been
confirmed both internationally and nationally that even with
proper planning , design and implementation of correct
procedures and personnel training, the development of
advanced technology and careful precautions, accidents seem
to occur periodically in the drilling for oil (Doust and
Huang,1992;Ofurhie, 2001). All activities of the oil industry
such as prospecting, production and refining have been found
to have negative effects on the environment. Oil spillages,
deforestation, acid rain, noise pollution and others are some
of the effects of oil activities that are highlighted in the
following sections.
International Journal of Agricultural Sciences and Natural Resources 2014; 1(4): 76-80 78
2.2. Specific Environmental Effects
2.2.1. Prospecting
Prospecting activities involve the searching for oil in
possible sites. This is the first stage in the exploration for
crude oil. These activities usually results in physical noise,
electrical/electronic and chemical pollution with devastating
effects.
2.2.2. Physical Pollution
This became obvious in the early 1960s when surveyors
started clearing virgin forests and swamps. During the
preparation of the well site, a lot of trees are cut down, which
result in disturbance of terrestrial ecosystems. The supply of
timber, which is useful in building houses, construction and
other commercial activities, greatly reduced so that the
income from these resources is also reduced. Marked
deforestation will also lead to exposure of soil surfaces,
which will lead to erosion and washing away of the top soil
principally by rain. The nutrients in the soil are reduced as
well as reduction in agricultural activities.
2.2.3. Noise Pollution
During prospecting, geophysicists shoot their geophysical
lines to locate specific hydrocarbon traps and oil wells.
Seismic technology is the most reliable and widely used
exploration tool in the oil industry. It involves the creation of
seismic waves at the subsurface and the recording of their
times of arrival at specific locations. Explosives and fire
electrical devices are employed in this process and in most
cases have caused the migration of fauna. The affected
environment has reduced agricultural potentials because of
the reduction of animal waste that might have served as
fertilizers and manure for enriching the soil. The noise
pollution resulting from oil production affects both man and
animals alike. Since production is a continuous process, the
effect of noise is an ongoing and long lasting one. Noise also
results from the vibrations and mechanical movement of
components of the drilling rig and other equipment.
Light and heat pollution results from gas flaring activities
which forms a basic problem in the Niger-Delta. Flaring of
gas alters the environment and contributes to global warming,
acid rain and other sundry negative environmental effects
(Ogbuigwe, 2001).
2.2.4. Chemical Pollution
Prospecting results in the destruction of topsoil and the
infiltration of chemicals into the aquifers. The net effect of
prospecting activities has been the gradual environmental
degradation and alteration of the ecosystem of the area such
as the total destruction of the virgin mangrove forest in
Igbokoda area of Ondo State in 1988/1989 (Abulu, 2001 and
Onuoha, 2004).Oil production processes usually pollute the
environment through the dumping of chemicals, drilling mud
and oil around wellheads. Valve failure around flow stations
and material failure along pipelines are regular sources of
pollution. This occurs in both offshore swamps and land
areas but the more devastating effects are noticeable in the
swamps. Here, the channels and stagnant water bodies are
covered by oil and oil-associated chemicals. As a result, the
ecosystem is severely damaged since fish, birds and other
animals in the vicinity are killed or scared away leading to
loss of natural animal habitats and sanctuaries. Thus,
chemical pollution destroys the environment, truncates the
food chain and has a lasting effect on the health of animals
and humans in the community
2.2.5. Oil Transportation
Crude oil is transported by pipelines and tankers and could
result in pollution as follows. Transportation by pipelines
over land or through the sea is a veritable source of pollution
resulting from either seepage or leakage, breakage of pipes
due to accidents or material failure and sabotage or
vandalization of pipeline facilities that is a common
occurrence in the Niger-Delta. Pollution resulting from
pipelines could be slight or massive depending on the
quantity of oil spilled. However, the direct physical, chemical
or fire damage caused by the effects of this pollution is
always devastating and often alters the ecosystem on a
permanent basis.
Transportation of gas, crude oil and associated products
could be by land (road or rail) tankers, or by water (sea)
tankers or super tankers. The pollution resulting from these
tankers could be slight discharges from small quantities
arising from washing out of tankers containing crude oil into
the water bodies or heavy discharges from ship accidents
such as the Armoco Cadiz spillage of 1979 and Exxon
Valdeze spillage of the 1980s. The net result of the pollution
is the same in which fauna and flora are totally destroyed
resulting in irreparable damage to the ecosystem.
In the downstream sector, refined products cause less
damage than the heavy crude but nonetheless leaking
pipelines and tanker collisions can lead to loss of lives due to
the combustible nature of refined petroleum products. Spent
oils such as used engine oils and naphthalene often result in
contamination of the environment due to indiscriminate
dumping. These oils degrade farmlands, pollute water bodies
and block drainages thereby resulting in reduction of
agricultural, fishing and environmental activities.
Ukpong (2001) investigated the Niger-Delta Ecosystem at
various locations from the viewpoint of sustainable
agriculture, fishing and environmental quality. The study
showed a high level of degradation in areas of oil
exploitation and the resultant effects on both plants and
animals. This point to the fact that communities in which oil
activities take place are subjected to environmental abuse and
therefore needed remediation.
3. Ecological Effects of Oil Activities
on Flora and Fauna in the
Niger-Delta
Ecological disequilibrium occurs when the natural factors
of the environment are modified by man in the course of
79 Emmanuel Teryila Tyokumbur: Review of Ecological Effects of Oil Exploration in the Niger-Delta, Nigeria
resource exploitation (Ukpong, 2001). The damage to the
fragile Niger-Delta ecosystem occurs due to indirect
modification as a result of petroleum exploitation. Since the
late 1950s, environmental deterioration has increased
proportionately to increase in totality of external
surroundings of man and other forms of life are not excluded
from the environmental perturbation that has replaced the
natural dynamic equilibrium situation in the Niger- Delta
ecosystem.
3.1. Ecological effects of Oil Exploration on
Plants and Economic Crops
3.1.1. Deforestation
During the preparation of oil sites for exploitation, viable
economic trees are cut down. This leads to a decrease in the
supply of trees or timber for building houses, constructing
bridges and other wood related commercial activities. The
removal of these trees results in the leaching away of topsoil
due to exposure of soil surfaces. The nutrients in soils found
in this environment are reduced and culminates in a marked
reduction of agricultural activities. Deforestation also results
in erosion due to the direct downpour of rain on the
unprotected soil in the Niger-Delta.
3.1.2. Damage to Farmland
Oil spillage at exploration sites and along the pipelines
will result in damage to farmlands. There is destruction of the
topsoil, which supports plants and allows the infiltration of
chemicals into the aquifer. Drilling activities also result in the
scraping of the topsoil. Depletion of essential nutrients from
the ground will lead to abnormal plant growth which
culminates in reduction of production output.
3.1.3. Water Salinization
Water salinization may be caused by disposal of industrial
wastes and oilfield brines. This disturbs the use of clean
water particularly for irrigation of sensitive crops. The loss of
fertile agricultural land and reduced crop yields caused by
water shortage and oil salinization of irrigated areas
destroyed the livelihood of whole communities, some of
which depend solely on agriculture as a means of survival.
3.1.4. Hydrocarbon Pollution of Soils and Air
Some parts of the Niger-Delta such as Ifie, Warri and
Ibeno were studied by Ukpong (2001) on pollution of soils
meant for crop cultivation. These areas were chosen due to
the continuous activities of major oil exploiting companies in
the region. Expectedly, yields were low in affected areas.
During exploration for crude oil, dynamites shot into the
ground cause uncontrollable gushing to the surface. The flow
usually occurs along gradients into creeks or basin wetlands
where vegetation is starved of air as anaerobic conditions are
created. Where soils are polluted by hydrocarbons, soil
organisms are destroyed, decomposition is slowed down,
anaerobic conditions are created due to blocking of soil pores
and nutrients are depleted. As a result of these, there tends to
be a decrease in soil nutrient values as pollution becomes
more severe. Increase in pollution leads to decrease in
production output of food and cash crops and an overall
reduction in financial earnings.
Atmospheric pollution arising from gas flaring also affects
the soil as rain passes through the atmosphere to soil surfaces.
Considerable volumes of petroleum associated acids also find
their way into the soil and water channels and affect viable
plant growth.
3.2. Ecological Effects of Oil Exploration on
Man and other Organisms
One of the routine soil and water quality parameters in the
Niger-Delta is hydrocarbon. Ukpong and Akpan (2001)
investigated the Total Hydrocarbon (THC) levels in some
water bodies in the Niger-Delta and came up with the
following results.
Table 1. Total Hydrocarbon (THC) values in Water Samples from Selected
Areas in the Niger-Delta
Location THC (ppm)
Warri River 150,000
Ugbodede Creek 18,000
Ogune Creek 20,000
Edjeba River 60
The results show that hydrocarbon pollution is high and
spreads faster in tidal areas. This spread can be phenomenal
particularly if the source is offshore and the current is
onshore in the direction as is usually the case along the
Niger-Delta shoreline. In these polluted waters, sediment and
mangrove mud becomes impregnated with hydrocarbons far
from the pollution source and the effects include destruction
of fish spawning grounds, decline in plankton that fish feed
on and destruction of fishing as a profession. Human health
in these areas deteriorates proportionately to the level of
water pollution. Gas flaring has also been shown to cause
infertility problems due to the heat emitted and respiratory
problems due to the toxic substances that they breathe in.
Other health effects of oil pollution on the community and
workers include excessive heat and colds, falls from tall
heights, disability from fire and explosion, dermatitis from
improper handling of spillage materials, respiratory disorders
and carcinogenesis.
3.3. Remediation of Affected Sites
Proposed remediation of affected sites include clean-up
programs and remediation. In the context of the environment,
remediation implies attempts to restore by deliberate action,
the natural equilibrium condition that has been destroyed
(USEPA, 2000; Ukpong, 2001; Victor and Esin, 2005).
Arguably, the Nigerian oil industry is currently immersed in
an era of sustainable development, which is consequent upon
the growing awareness on environmental issues and concerns.
Environmental degradation due to hydrocarbon
contamination has over the years been an integral part of
exploration and production activities in the Nigerian oil and
gas industry. The most significant large-scale entry of crude
oil and associated pollutants into the ecosystem is through
International Journal of Agricultural Sciences and Natural Resources 2014; 1(4): 76-80 80
accidental spills and gas flaring. Efforts have been made by
the major oil companies in the Niger-Delta to cushion the
effects of environmental pollution through various innovative
environmental management systems and approaches. These
approaches have proved effective both in the land terrain and
in the swamps with much successes recorded in offshore
spillage cleanups.
4. Conclusion
Environmental pollution and the adverse effects on the
host communities of oil exploration sites in the Niger-Delta
is an important issue that requires urgent and prompt
attention in view of the fact that petroleum production forms
the major natural-based resources on which the country
depends. Policy makers of the various oil exploration
companies should realize that there is need to protect the
health, safety and welfare of these communities.
The communities and the inhabitants have to be well
protected and some of the health and safety measures which
members of the company staff benefit should be extended to
members of the host community. Also these companies must
adhere to relevant government legislation aimed at protecting
lives and property in their areas of operation to maintain and
ensure minimal environmental degradation. Reduction of
morbidity and mortality resulting from exposure to
environmental pollutants and improvement of the overall
productivity of the communities will result in a boost for the
country’s economy.
Acknowledgement
Literature searches by Mr Ikuomola Olumide Temitayo are
hereby acknowledged.
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