| Dr. P.C. Nwilo & O. T. Badejo
Department of Surveying and Geoinformatics
Faculty of Engineering
University of Lagos, Akoka – Lagos, Nigeria
Nigerian Coastal AreasNigeria has a coastline of approximately 853km facing the Atlantic Ocean. This coastline lies between latitude 4o 10’ to 6o 20’N and longitude 2o 45’ to 8o 35’ E. The Nigerian coastal area is low lying with heights of not more than 3.0 m above sea level and is generally covered by fresh water swamp, mangrove swamp, lagoonal mashes, tidal channels, beach ridges and sand bars (Dublin- Green et al, 1997).
The Nigerian coast is composed of four distinct geomorphological units namely; the Barrier-Lagoon complex; the Mud coast; the Arcuate Niger delta; and the Strand coast (lbe, 1988). The vegetation of the Nigerian coastal area is also characterised by mangrove forests, brackish swamp forests and rain forests.
The coastal zone is richly endowed with a variety of minerals. The most important of these are oil and gas. Since the first shipment of crude oil in 1958, there has been an upsurge in oil exploration activities in Nigeria. These have led to the discovery of numerous oil fields and subsequently to the development of various oil terminals (Ozobia, 1998). The Nigerian coastal zone is richly endowed with oil and gas. Nigerian crude oil reserve is over 25 billion barrels, while the crude oil production per day is estimated at 2.2million barrels. Oil production activities are increasing. The Nigerian Government is aiming at increasing the reserve capability from 25 billion barrels to 30 billion barrels in 2003. By 2003, daily crude oil production is expected to hit 3.0millon barrels.
Review of Oil Spill Incidents in Nigeria
Oil spillage is categorized into four groups: minor, medium, major and disaster. Minor spill takes place when the oil discharge is less than 25 barrels in inland waters or less than 250 barrels on land, offshore or coastal waters that does not pose a threat to the public health or welfare. In the case of the medium, the spill must be 250 barrels or less in the inland water or 250 to 2,500 barrels on land, offshore and coastal water while for the major spill, the discharge to the inland waters is in excess of 250 barrels on land, offshore or coastal waters. The disaster refers to any uncontrolled well blowout, pipeline rupture or storage tank failure which poses an imminent threat to the public health or welfare (Ntukekpo, 1996).
Oil spillage in Nigeria occurs as a result of sabotage, corrosion of pipes and storage tanks, carelessness during oil production operations and oil tankers accidents. In Nigeria, fifty percent (50%) of oil spills is due to corrosion, twenty eight percent (28%) to sabotage and twenty one percent (21%) to oil production operations. One percent (1%) of oil spills is due to engineering drills, inability to effectively control oil wells, failure of machines, and inadequate care in loading and unloading oil vessels.
Most of the oil pipes and tanks in the country are very old and lack regular inspection and maintenance. Thousands of barrels of oil have poured into the environment through some of the corroded pipes and tanks. A recent major occurrence was that at Idoho, an offshore platform in south-eastern Nigeria, where about 40,000 barrels of oil spilled into the environment. Sabotage is another major cause of oil spillage in the country. Some of the inhabitants of the oil rich Niger Delta engage in oil bunkering and from time to time damage and destroy oil pipelines in their efforts to collect oil from them.
Oil spill incidents have occurred in various parts and at different times along our coast. Between 1976 and 1998 a total of 5724 incidents resulted in the spill of approximately 2,571,113.90 barrels of oil into the environment. Some major spills in the coastal zone are the GOCON’s Escravos spill in 1978 of about 300,000 barrels, Shell Petroleum Development Corporation’s (SPDC’s) Forcados Terminal tank failure in 1978 of about 580,000 barrels, Texaco Funiwa-5 blow out in 1980 of about 400,000 barrels, and the Abudu pipe line spill in 1982 of about 18,818 barrels (NDES, 1997). Other major oil spill incidents are the Jesse fire incident which claimed about a thousand lives and the Idoho Oil spill in January 1998, in which about 40,000 barrels were spilled into the environment (Nwilo et al, 2000). The most publicised of all oil spills in Nigeria occurred on January 17 1980 when a total of 37.0 million litres of crude oil got spilled into the environment. This spill occurred as a result of a blow out at Funiwa 5 offshore station. The heaviest recorded yearly spill so far occurred in 1979 and 1980 with a net volume of 694,117.13 barrels and 600,511.02 barrels respectively.
Table 1.0 below shows data on oil spill incidents in the country between 1976 and 1998. Figure 1.0 also shows the graph of the number of oil spill incidents per year in the country. The graph clearly indicates that the lowest oil spill incidents occurred in 1977, while the highest number of oil spill incidents happened in 1994. Figure 1.1 also shows the graph of quantity of oil spilled per year in the country. The lowest quantity of oil was spilled in 1989, while the highest quantity was spilled in 1979.
Table 1.0: Oil Spill Data
Source: The Department of Petroleum Resources
IMPACTS OF OIL SPILL
Major oil spills heavily contaminate marine shorelines, causing severe localised ecological damage to the near-shore community. The harmful effects of oil spill on the environment are many. Oil destroys plants and animals in the estuarine zone. It settles on beaches and kills organisms and marine animals like fishes, crabs and other crustaceans. Oil endangers fish hatcheries in coastal waters and as well contaminates the flesh of commercially valuable fish. Oil poisons algae, disrupts major food chains and decreases the yield of edible crustaceans. It also coats birds, impairing their flight or reducing the insulative property of their feathers, thus making the birds more vulnerable to cold.
Oil on water surface also interferes with gaseous interchange at the sea surface and dissolved oxygen levels will thereby be lowered. This will in no doubt reduce the life span of marine animals. Micro-organisms also degrade petroleum hydrocarbons after spillage (Atlas, 1981; Leahy and Colwell, 1990; Atlas and Bartha, 1992)
In a bid to clean oil spills by the use of oil dispersants, serious toxic effects will be exerted on plankton thereby poisoning marine animals. This can further lead to food poisoning and loss of lives. Another effect of oil slicks is loss of economic resources to the government. When spilled, oil is not quickly recovered, it will be dispersed by the combined action of tides, wind and current. The oil will therefore spread into thin films, dissolve in water and undergo photochemical oxidation, which will lead to its decomposition.
On the Nigerian Coastal environment, large areas of the mangrove ecosystem have been destroyed. Oil spill has also destroyed farmlands, polluted ground and drinkable water and caused drawbacks in fishing off the coastal waters. There has been continuous regional crises in the Niger Delta area as a result of oil spill pollution of the coastal ecosystem. The oil producing states are now calling for control of oil resources in their respective states.
The Idoho oil spill of 1998 polluted coastal waters from Akwa Ibom State in the east to Lagos State in the west. Mobil Producing Unlimited commissioned a verification exercise to determine the extent and impacts of this oil spill. During the verification exercise, it was observed that the spill destroyed fishing nets, boats, and fishing ponds.
Ogoni and Oil
The Ogonis, whose population of 500,000, once made a living from farming and fishing. For over 30years Shell and Chevron financed drilling on Ogoni land. This has increasingly pushed the population into the forests and mangrove swamps. Those who remain in the townships and villages are subjected to displacement and expropriation of their properties. The Ogoni have received virtually none of the $30 billion from oil pumped out of their lands, and they have been actively demonstrating against such injustices.
The movement for the survival of Ogoni People (MOSOP) and other Ogoni activists have on several occasions called on the Nigerian Federal Government to regulate the oil exploration, drilling, and processing activities of Shell Oil and other oil companies in the oil producing regions of Nigeria. Mr. Ken Saro-Wiwa, along with eight other MOSOP members, were arrested and charged with the murder of four traditional chiefs belonging to a pro-government group in the Ogoni region. The murders occurred during a bloody clash in May 1994 between Ogoni activists and Federal Government soldiers. On October 31, 1995, a Federal military tribunal sentenced them to death. On November 10, 1995 the Nigerian Federal Government hanged Ken Saro-Wiwa and eight others, in Port Harcourt. Ken Saro-Wiwa’s final words before he was hanged were “Lord take my soul, but the struggle continues.” (TED Case Studies, 1997).
Reactions by the international community after the Federal Government hanged Ken Saro Wiwa and eight others were swift and included:
MANAGEMENT OF OIL SPILLS IN NIGERIA
A number of laws already exist in the Nigerian oil industry. Most of these laws provide the framework for oil exploration and exploitation. However, only some of these laws provide guidelines on the issues of pollution (Salu, 1999). According to the Federal Environmental Protection Agency, Lagos Nigeria, the following relevant national laws and international agreements are in effect namely:
References to Caps, volumes and pages are as in the laws of the Federation of Nigeria. Some of the acts and regulations on pollution given by (Oshineye, 2000) are given below:
The Federal Environmental Protection Agency (FEPA), which was recently made part of the Ministry of the Environment is legally vested with the responsibility of protecting and sustaining the Nigerian environment through formulation and implementation of regulatory frameworks. The National Policy on the Environment (1989) comprises one of the instruments developed by the agency to carry out its tasks. The document describes guidelines and strategies for achieving the policy goal of sustainable development (Ntukekpo, 1996).
Due to increasing awareness in preventing and controlling spills in Nigeria, the Clean Nigeria Associates (C.N.A.) was formed in November 1981. The C.N.A. is a consortium of eleven oil companies operating in Nigeria, including N.N.P.C. The primary purpose of establishing the C.N.A is to maintain a capability to combat spills of liquid hydrocarbons or pollutants in general. The Environmental Impact Assessment (EIA) decree No 86 of 1992 was promulgated to protect and sustain our ecosystem. The law makes EIA compulsory for any major project that may have adverse effects on the environment (Ntukekpo, 1996; Olagoke, 1996). The Decree was to control activities that have environmental impact on the host communities, facilitates the promotion and implementation of policy, encourage information exchange. It sought to assess the likely or potential environmental impacts of proposed activities, including their direct or indirect, cumulative, short term and long term effects, and to identify the measures available to mitigate adverse environmental impacts of proposed activities, and assessment of those measures. The guidelines made provisions for offshore operations, safety measures, liability and compensation (Ozekhome, 2001).
Effective response to a marine oil spill requires knowledge of the sensitivity of the coastal zones. This will enable the determination of priorities for protecting the most sensitive areas. In order to assist the decision-makers in choosing the areas of priority, coastal sensitivity maps of Nigeria including areas of ecological and socio-economic interest must be produced.
As part of an environmental baseline studies project for the Nigerian National Petroleum Corporation (NNPC), sixty coastal and two hundred riverine/estuarine stations were studied in 1984 and 1985. Data gathered at these stations were used in describing regional and site-specific shoreline types. The outer coastline of Nigeria was divided into five broad categories, and within these categories, the shoreline has been divided into Environmental Sensitive Index (ESI) shoreline types. In addition, an ESI scale was developed and applied for the tidally influenced Bonny/New Calabar mouth and estuary.
ESRI Professional Services has been contracted to develop a widely useful set of standards and protocols foe generating Environmental Sensitivity Index (ESI) maps for coastal and inland interior areas of the Niger Delta in southern Nigeria. These protocols permit the efficient, consistent development of reliable ESI maps, concepts and procedures. These protocols can be used in many other parts of the world as well.
Development of the protocols was funded by the Oil Producers Trade Section (OPTS), whose member companies explore for, and produce oil within and offshore of, the Niger Delta. Nigerian regulatory requirements specify ESI mapping as part of contingency planning for oil exploration and production activities to better protect the delta’s natural resources. Working with ESRI is co-contractor Environmental Resource Management Limited (ERML) of Nigeria.
A successful combat operation to a marine oil spill is dependent on a rapid response from the time the oil spill is reported until it has been fully combated. In order to reduce the response time and improve the decision making process, application of Geographic Information Systems (GIS) as an operational tool is suggested. Information on the exact position and size of the oil spill can be plotted on maps in GIS environment and a priority of the combat efforts and means according to the identified coastal sensitive areas can be carried out. GIS offers opportunities for integration of oil drift forecast models (prediction of wind and current influence on the oil spill) in the computer program framework (Milaka, 1995).
Required information for oil spill sensitivity mapping can be depicted on a set of thematic maps using GIS even though they can in theory be depicted onto a single sheet. With the use of a GIS, however, all the relevant information or themes can be stored in the system and produced onto maps in a format that befits the needs of the day. Alternatively, modelling exercises using the GIS can be conducted to assess the adequacy of any given oil spill contingency plan (Parthiphan, 1994).
The creation of regional spill response centres along Nigerian coastlines will help in managing oil spill problems (Smith and Loza, 1994). The centres will use oil spill models for combating oil spill problems. Using data collected with an airborne system to input one or several new starting point(s) into the model, will improve the accuracy of the further predictions (Sandberg, 1996). Oil spillage can also be treated or removed by natural means, mechanical systems, absorbents, burning, gelling, sinking and dispersion. Oil spillage can be removed by natural means through the process of evaporation, photochemical oxidation and dispersions (Smith 1977). Bioremediation can also be used for managing oil spill problems (Hoff, 1993; Prince, 1993).
An effective response to a marine oil spill requires knowledge of the sensitivity of the coastal zones. This will assist in determining priorities in event of an oil spill. In order to assist the decision-makers in choosing the areas of priority, coastal sensitivity index maps of Nigeria including areas of ecological and socio-economic interest must be produced at large and medium scales.
CONCLUSION AND RECOMMENDATIONS
There is a need to acquire real time or predicted meteorological data and medium scale digital maps of the coastal areas. Establishment of regional spill response centres along the coastline, and the use of data collected with an airborne system will help in managing oil spill problems in Nigeria.
The petroleum industry should work closely with government agencies, universities and research centres to reduce the frequency and impact of oil spills. When a spill occurs, various government agencies and industries must start to immediately to clean the spilled oil and efforts made to minimise its impact on the environment.
The GIS could be used to identify responders and provide information about the closest resources of oil spill response equipment and personnel. Planners to review could also use it where spill-fighting resources are deployed. The petroleum industry should work closely with government agencies, universities and research centers to reduce the frequency and impact of oil spills.
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