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            Due to the negative effect of oil spillage on the environment, recently Nigeria President Muhammadu Buhari flag up campaign for cleaning up of the Ogoni Land in Niger Delta region of the country, he was ably represented by the Vice President Professor Yemi Osibanjo.

            Traditional environmental problems have been rife ever since the creation of man. Notable among these are the generation of domestic waste and later, industrial wastes. The generation of domestic wastes is as old as human activity or human existence, and the environmental effects are widespread.

             Cases of oil spill have been an isolated issue occurring perhaps randomly in countries using oil as power source or as a source of income. The prominence gained by oil spills is mainly due to its pollution and devastating environmental effects. International recognition of oil spill seemed to have started with the oil spill from the Torrey Canyon disaster of 1967 in a reef in the English Channel. This oil spill with the attendant pollution then attracted the attention of the French and English governments. Further developments in oil activities in other countries of the world resulted in other cases of oil spills in different parts of the globe.

              Oil in this context and in all its ramifications connotes petroleum, and all its allied products. Oil spill parse can be said to connote the process of oil accidentally coming out or seeping out from pipe or any other container, hitherto containing oil. Put more succinctly, oil spill is an accidentally or intentional discharge of oil which may reach water bodies (FEPA, 1991) or any other part of land. In this sense, the type of oil spill can include petrol spill, gas spill and diesel spill. The effect of any of these spillages is not negligible.

              As already indicated, oil spills occur in oil producing/consuming areas of the world. In Nigeria, cases of oil spill are rife. One is reported by Imerson (1976) to have occurred in Bomu in 1970 where oil was spilled over an area of approximately 108 hectares. Other cases of oil spill in Nigeria is reported by Ogbonna (1981) include the Obagi spill in 1971, Bori spill in 1973 and Obirikom spill in 1977 among others. Oil spillage can occur from the refineries, oil pipelines, deports and pump stations. Activities connected with each of these segments have adverse environmental effects. For instance, in connection with petroleum transportation process is the unavoidable presence of oil leak from the pipes and tankers. We will now consider the possible causes of oil spills in general and Nigeria in particular.

CAUSES OF OIL SPILL 
              In recent times, oil spill has been identified as one of the greatest single environmental problem all over the world. According to the European Environmental Agency (1998) accidents such as oil spills constitutes a unique class of environmental problem. The agency recognizes oil pollution as resulting from accidental oil spills and natural oil seepage. In essence, there are diverse causes of oil spills. Ahman (1992) in her key note address at the opening session of a workshop during an Environmental Day states that the “immediate causes of the spillages range from break up or damage to oil tankers or storage vessels to sabotage by aggrieved people”. Ofomata (1997) observes that in addition to blowouts, cases of local oil spills can occur as a result of improper handling or mishaps such as burst pipes…..or from continuous seepage from the jetties during the loading of vessels, or from the deliberate action of foreign ships dumping their oil-sodden ballast into our coastal waters and gas flaring.

              As a matter of fact there has not been a comprehensive documentation of oil spills by causes apart from random reports. It is even estimated that the contribution from routine actions such as flushing oil tankers at time exceed the level of oil pollution from oil spill.

              Within the last few decades in Nigeria, pipeline vandalization in oil producing area or in area traversed by oil pipeline has been on the increase. The issue of oil pipeline vandalization has been increased mainly as a result of rising oil price and petroleum scarcity sometime in Nigeria. The vandals hope to make enormous profit from such act. Many other times, the vandalization is perpetuated by angry villages in the oil producing area who may not be contented with the level of attention paid to them by the government and oil producing companies.

               Another cause of oil spill is the leakage of oil from the pipeline. This is normally brought about by old and worn-out pipelines which due to old age starts rusting and eventually leaking oil. In other case, the leakages are caused by vehicular or other accidental contact with the pipeline especially where the pipelines are exposed to the surface.

              Oil spill by vehicular tankers are becoming prominent. Apart from the pipeline oil distribution, vehicular tankers play active role in this respect. Many times there are oil spills from these tankers brought about by accidents and leakages. Such accidents when initiated are aggravated by fire outbreak, which then result in more spills and more environmental effects.

              Oceanic accidents involving oil carrying ships bring about oil spills. Probably, the Torrey Canyon disaster in the English Channel in 1967 might be a good example. In this disaster, as reported by Vesilind and Pierce (1982) “…..the huge tanker loaded with crude oil plowed into a reef……and almost immediately oil began seeping out. Almost all the oil eventually leaked out and splashed on the beaches. These oceanic oil accidents obtain in areas or countries which use water for oil distribution.

                The cases of oil spill in Nigeria depend to a large extent on the distribution of oil wells.
SUMMARY OF WELL DRILLED IN VARIOUS ECOLOGICAL ZONE (1960-1985)

Year
Offshore
Land
Swamp
Total
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
-
-
1
1
28
48
54
65
61
83
78
84
74
91
92
63
41
41
33
42
34
49
41
40
35
19
25
20
30
39
52
79
118
76
71
63
53
88
115
112
114
95
59
41
48
48
46
66
47
24
29
23
7
4
7
9
14
30
43
26
10
6
24
51
61
34
44
37
48
40
33
41
44
36
28
18
14
25
32
24
38
49
94
163
215
165
150
152
155
223
250
237
250
195
148
122
114
137
124
157
116
82
78
67
Total
1,196
1,581
748
3525
 Source: S.N. Uchegbu (2002, p.33)
              From the above table it is clear that from 1960 to 1985, Nigeria has a total of 3525 cases of oil wells comprising offshore, land, swampy ecological zones. Out of this total 33.3% are offshore; 44.9% on shore and 22.2% from swampy environment. Thus the percentage which is on land is substantial. Therefore, substantial oil spill can be expected from it. None of the others, where offshore drilled or swamp drilled may be free from all accidental spill.

              On their part Olapade and Olusegun (1997) stated that oil spills result from;
(i) Overflowing storage tanks overturned vehicle or fractured pipeline.
(ii) Smaller but, perhaps repetitive losses of oil which often arise from careless handling of small factories and similar installations.
(iii) The surreptitious dumping of waste oils.
              They went further to summarize that causes of oil spill may include pipeline leakage, leakage at drilling rigs disposal of used oil or lubricant, gas flaring, usage of chemicals among others.

EFFECT OF OIL SPILL ON ENVIRONMENT 
POSITIVE EFFECTS: 
             The greatest positive contribution of oil to the development of Nigeria is through the improvement in the economy. The Petroleum sector’s contribution to government revenue over the years is enormous. As at late fifties and sixties, the total dependence of the economy on the oil sector appreciated as shown in the table below:

CRUDE OIL EXPORTS 1958/66 


Year
Export in the Sand Ton
Value in Thousand
1958
1959
1960
1961
1962
1963
1964
1965
1966
245
538
828
2,224
3,368
3,695
5,783
13,019
18,945

979
2,702
4,408
11,546
16,739
20,176
32,057
68,097
91,973

          Source: S.N. Uchegbu (2002 p.35)
             The contribution of oil to the economy continued to present to a level of about 80%. Specifically from 1967 to 1979/80, the breakdown of the petroleum sector contribution to government revenue is shown below:  


PETROLEUM SECTORS CONTRIBUTION TO GOVERNMENT REVENUE. 1967/68 to 1979/80
Fiscal Year
Fed. Govt. (N’000) Revenue
Revenue from Petroleum (N’000)
% share of Petroleum total revenue
1967/68
1968/69
19/69/70
1970/71
1971/72
1972/73
1973/74
1974/75
1975/76
1976/77
1977/78
1978/79
1979/80
300,197
299,986
435,908
755,605
1,410,911
1,389,911
2,171,370
5,177,063
5,252,297
5,756,328
7,652,500
6,815,200
11,809,100
41,884
29,582
75,444
196,390
740,185
567,151
1,549,383
4,183,816
4,568,425
4,833,713
6,459,000
5,458,500
9,869,800
13.95
9.86
17.31
25.99
52.46
41.45
71.36
80.81
86.98
83.97
84.04
80.01
83.57
          Source: S.N. Uchegbu (2002 p.36)








              The table shows clearly that the continued increase in revenue from the oil sector and as a matter of fact, the contribution has continued till date.
Apart from the contribution to the economy, the whole process of petroleum exploration service, refining and marketing provided employment for thousands of Nigerians (Ofomota, 1997). According to Ofomota, the oil companies awarded scholarships to some Nigerians. In addition to providing roads, maps, etc which have been of immense value to Nigerians, they contribute to the training of Mechanics, drillers, seismic operators and laboratory operators thus developing the human resources (Udo, 1981).
          The oil industry provides other available energy sources such as petrol, kerosene, diesel oil, heavy fuel oil, and bottled gas. Moreover, the oil industry contributes directly to the Federal for more economic growth of the country.
NEGATIVE EFFCT OF OIL SPILLS
          The problems inherent in oil spills are wide spread in their effects and long lasting in duration. The effects of oil spills throughout the world may be the same since the vegetation, waterbodies, soil and groundwater are affected. The Torray Canyon disaster in 1961 earlier mentioned affected the environment negatively.
          During the Gulf War, the oil released from Kuwait’s sea terminal was out at about 950,000 cubic metres. The spilled oil polluted the coast of Saudi Arabia (outreach 1992). Accordingly, there was water pollution, destruction of vegetation and nesting place for birds and the like. Also, affected were the lives of aquatic animals living in the sea. Despite the management efforts by these fairly advanced countries to avert spills, they do not occur frequently or once in a while.
          In Nigeria, the effect of oil spill according to Ahman (1992) include lost of fish and aquatic animals, devegetation and other form of ecological damages, loss of drinking and industrial water, and so on. Ahman observed that when there was an oil spillage in Bonny Local Government Area (LGA) of Rivers State, it was not possible then to find portable (drinking) water anywhere in the entire L.G.A.
          A review of the yearly distribution of oil spills, in Nigeria for instance, would help to drive home the outlined above.
          The table below summarizes the magnitude of the oil spill problem.

YEARLY DISTRIBUTION OF OIL SPILL IN NIGERIA (1970-1982)
S/No
Year
No. of Spills
Net Volume (BBLS)
1
2
3
4
5
6
7
8
9
10
11
12
13
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1
14
41
59
105
128
128
104
154
157
241
233
46
180
15,111
15,390
95,580
65,714
56,854.82
20,023
31,144
97,250
630,405
558,053
22,840
34.4
Total
13 years
4,581
1,678,989.42
Source: S.N. Uchegbu (2002 p.38)
 
As a matter of fact, about 1,678,989.42 Barel Per Litre (BPLS) of oil were discharged to the environment within a period of 13 years. One could only imagine the tremendous effect on the environment and particularly on man.

          Initially, it was thought that the oil spills and their negative effect are localized in the oil producing areas but this is no true as they also occur along oil pipelines which traverse none oil producing areas enroute to oil dumps and other stations.  However, most of the negative effects are experienced in the oil producing areas comparative to other areas. For instance, the Niger-Delta basin with its very delicate riverine and mangrove ecology serving as a source of food for shrimps with an estimated yield of about 50,000 metric tone per year is being devastated instantly by oil spill and pollution problems.
          By and large, the extent of the potential damage that could result from oil pollution which resulted from oil spill depend on the severity of the oil spillage, the toxicity of the oil and the type of environment (Ene-Ita, 1984). The next table is a summary of potential effect of oil spillage, pollution and oil related activities on the environment.

POTENTIAL IMPACT OF OIL OPERATION ON THE ENVIRONMENT
Gas Operation
Potential Impact on the Environment
Gas Flaring
Causes very high temperature with excessive noise and vibrations around the area. The excessive heat scorched and withered some vegetation especially palm-trees. Air pollution from the incomplete combustion of the gas flare is noticed.
Oil Drilling/Leakages
-Accumulation of toxic material from drilling materials.
- Oil pollution of the sea, beaches or land.
- Destruction of fisheries ground for some marine fishes.
- Alteration of the taste of fishes.
- Killing of bottom dwellers.
-Pollution of underground water.

Flat form and tank forms
- Water and land pollution from sanitary.
- Waste, used and leaked lubricating oil.
Gas Flaring (extra)
- Suppressed the growth and flowering tree
- Destruction of mangrove swamps and salt.
- Aesthetic devaluation.

Loading, location spillages (onshore and offshores)
- Spillage during loading operation with all its accompanying effect on the fauna and flora.
Transportation by pipeline , tankers
-Sedimentation along pipe line routes.
-Water pollution from consequences of leaks from fracturing or breaking of pipes cause by mental fatigue, trawlers and dredges or sea floor failure, or sabotages.
-Air pollution by transport tankers.
-Destruction of environmentally sensitive areas e.g. lowlands, where enturies, wetland and sand dumes fields exist.
-Erosion and flooding.
Storage Deports (spillage)
-Land pollution from chemical cons and drums.
-Air pollution from storage tanks.
-Air pollution from gaseous fumes during loading.
Refinery
-Water pollution by organic and inorganic pollutants including oil and grease.
Health Effects
-In almost all cases the health of man is affected.
          Source: S.N. Uchegbu (2002 p.39-40)
          Off all these oil operations, the lessons resulting from spill are greater. Example of oil spill incidents includes the following:
       i.            Shell 21 blowout in 1970
     ii.            the Setrap now Elf, Obagi blowout of 1971
  iii.            The Agip Oyakama pipeline leakage.
          An oil spillage from well blowout is disastrous as large quantities of oil are released to the environment. For example, the Funiwa V oil well blowout in 1980 resulted in the release of estimated 8.4 million gallons of oil into the Marine environment (Oil spill intelligence Report, 1982), the effect can be expected ranging from surface water pollution, ground water pollution and aquatic life losses.
          There are other cases of oil spills in Nigeria within attendant environmental effect, example is oil spill in Uzo in February, 2000 and from that time to present there were many cases of oil spills and vandalization which resulted in large degree of serious environmental pollution and acute fuel shortages in Nigeria.





CONTROL OF OIL SPILL
          According to Ofomata (1997) it would appear that the major obstacle to the solution to the environmental problem of oil spillage is the ultimate dependence of the political economy on the profit of the oil industry. However, in spite of this, solution and control measures have to be proffered. Various methods have been used to control pollution from oil spills. However, a saying that “prevention is better than cure”. The preventive measures to curb the incidence of oil spill are:
(1) Adequate maintenance of pipeline by prompt changing of old and worn out ones.
(2) Guarding of pipeline site to prevent vandalization and human induced leaks.
(3) Regular clearing of the bushes along which the traversed to make the pipeline visible to human in order to prevent accidental contacts capable of initiating leakages.
(4) Public enlightenment as to benefits of safeguarding oil installations and the possible negative environmental effects in case of oil pollution from oil spills.
          When these preventive measures are taken and either in case of error of omission or commission, there are oil spill, then remedial measures should be made to remove the spilled oil from the environment. The method normally used includes the following:
(1) Spreading straw on beaches: the use of straws on the beaches allow the straw to absorb the oil. The oil soaked straws are later collected and burnt. More straws means more oil being reduced. However, this method depends on the extent of spillage on the water body.
(2) The use of detergents: the use of detergent ensures that the oil or the water are dispersed and the emulsion are flushed off the beaches or water body.
(3) The use of boom and net: the booms and net are floating barriers that keep the oil from spreading. In this method, the barriers are substances that limit the spread of the oil.
(4) The use of skimmers: skimmers are machines that scoop off oil from a polluted water body. If the skimmers are in good condition, as much as 300,000 cubic metres of oil may be scooped up, especially in major spills.
(5) Spraying hot water at high pressure: when hot water is spread at high pressure over an oil spill area, oil may be removed possibly by evaporation.
(6) Sprinkling the shoreline with nitrogen base fertilizer to degrade the oil.
(7) Bioremediation: the use of bacteria and microbes to feed or degrade the oil.
(8) The use of chemical dispersants that act like detergents to break up the oil (Outreach 1992).
(9) Another effective way of dissluding or removing oil from any surface is called degreasing. The fairly viscous, non-corrosive chemical that is capable of performing this function is called dirthbaster (degreaser) (Adedeji, 2000).
          Composition of the degreaser include:
(i)                Sulphoric acid
(ii)             Coustic soda
(iii)           Soda Ash
(iv)           S.T.P.P
(v)             S.L.S
(vi)           Active solvents
(vii)        Essentials






Applications: when an appreciated quantity of this degreaser is generously applied to then affected surface, it emulsifies the hydro-carbon based substances, the emulsion that is formed and rinsed is effluent friendly and not harmful to the ecosystem. The beauty of it is that after days it grows algae which is a source of nutrients to the aquatic animals.
          However, for a more effective oil clean up, there is the need for a combination of method.
CONCLUSION
          The oil industry particularly in the area of exploration and exploitation, drilling well, transportation, e.t.c have had considerable impact on the environment which man inhabits. The gain from oil has been noted, but the negative effect seem to equate with the gain. According to reports about N5-6 billion are used annually by the Federal Government to control pipeline rehabilitation occasioned by pipeline vandalization and spillages.
          There is therefore the need for measures to be taken to prevent oil spillage or manage oil spillages effectively at the last cost. Our environment and man should not be allowed to suffer as a result of the presence of oil in Nigeria. As Ofomata (1997) rightly pointed out “the human environment is the basis for economic, social and cultural development and it is important that the quality of our environment be maintained in a good state so as to ensure a high level of societal performance, preservation of the ozone layers, maintenance and substance of human, aquatic and vegetation life as well as promotion of environmental of aesthetic among others.

Baba Ali Mustapha is with the Department of Planning/Research, Ministry of Environment, Maiduguri, Borno State.

Reference:
          The research work was based on the work of S.N. Uchegbu, the Associate Dean, Faculty of Environmental Studies, University of Nigeria, Enugu Campus, from his book, Issue and Strategies in Environmental Planning and management in Nigeria. Published by Stotelite Publishers, 27 Ochi Street, Achara Layout, Enugu, Nigeria.

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