By Olushola Adeshida
Historically, Apapa Local Government Area is reputed to be one of the modern day local government areas of Lagos State since its first creation in 1980. Human and economic activities as well as the development of the Apapa seaport have attracted the establishment of petroleum tank farm storage facilities and oil jetties within the Lagos harbour. In Nigeria, the Commodore channel, Atlas cove area and the entire Lagos harbor are located within Apapa local government area (LGA). Of keen interest also are the numerous jetties in the area. In this area, most spills occur as a result of either equipment failures or sometimes human errors and are frequent especially during transfer operations as between ships and shore. Other sources of oil spill in the environment include undetected discharges from storm sewers and tanker ballast operations. In addition, accidental discharge or spill of crude oil or refined oil products, as well as disposal of used or exhausted lubricants and waste oils, can have a deleterious effect not only on the environment but also on life forms within the environment.
The current population of Apapa, which is 217,362, has been projected to increase to 449,702 by 2020. Nonetheless, Apapa has a thriving transportation network which connects the area with other parts of Lagos State. Most of the roads in Apapa are of age thus requiring consistent maintenance to keep them in shape. The local council has in turn constructed culverts and drainages in order to ensure smooth water flow and roads have been constructed to ensure circularity and accessibility within the area. A portion of the local populace utilises water transport. This is due to the presence of the natural stretch of coastline that stimulates such movement particularly within the marine hydro-ecosystem. As a coastal marine ecosystem, nearness to roads becomes an asset to any location. For instance, oil spill locations nearest to roads could easily be accessed and remedial actions taken immediately than those that are not easily accessible. Eleven biological resources have been identified that were spatially distributed within the Apapa area. They include: shore birds, alligators, crabs, cray fish, crocodiles, diving birds, domestic animals, ducks, fishes, water birds, and other mammals.
Wherever an oil spill occurs, nature tries to adjust in a number of ways. These include evaporation of the lighter and more volatile components into the atmosphere. Heavier components tend to sink to the bottom of the sea. Biodegradation by micro-organisms in the sea is yet another method. Even unsuspecting birds and some animals come to peck at the oil mat. The cultural effect and implication of oil spill are immeasurable as it cuts across several aspects of human culture that not only are volatile and vulnerable but also could trigger migration, conflict, etc. Oil spill in coastal communities has oftentimes led to the destruction of traditional occupations such as artisanal fishing, canoe construction, net making, etc. as well as several indigenous cultural activities such as water-based cultural activities in many parts of the world. Oil spillage, depending on the nature of pollution, could also lead to unfit environmental area for living as a result of malodorous air thus reducing the ambient air quality. Traditional activities such as swimming and other local recreational uses of water will be adversely affected.
Oil Spill and Application of Environmental Vulnerability Studies
Information and technology and the competence to use them are essential for informed decision making
in land use/ resource planning. So far, substantial work has been carried out on the development of indices which depict the extent of oil spillage within a highly susceptible area, the vulnerabilities of coastal areas of the world as well as the level of risk to human, economic, social and ecological systems. In Nigeria, researchers have developed a new oil spill trajectory model which entail simulation from a point around OPL 250 located about 150km off the Nigerian coastline. It showed that the simulated oil spill for wet season reached the shore (around Penington River) after 104 hours (about 4.5 days). Also during the dry season, the results from the model indicated that the oil spill reached the shore (at the entrance of Benin River) after 162hours (6.5days). Nigerian researchers encourage the adoption of the merits of having the disaster monitoring constellation satellite owned by the Federal Government of Nigeria to monitor the oil spill trajectory for future studies.
So far, GIS was found useful as the requisite data for oil spill risk assessment are spatial in structure and nature. Thus, a combination of hazard and vulnerability data layers constitutes the GIS-based risk assessment methodologies used in the study. Hazard was modeled in the study by sources of petroleum oil spill moderated by surface characteristics, while data on crop suitability, socio-economy, environmental sensitivity, accessibility, and settlement development, were used to model vulnerability. The resulting risk layer was classed into four Risk zones of very high, high, moderate and marginal risk. Iko and the environs were found to be in the very high risk zone. Based on the fact that increasing investments are being made in the petroleum oil sector in Akwa Ibom State, the study analysed the implications of the findings and stressed the need for a comprehensive GIS based oil spill contingency plan for the area.
Oil Spill Vulnerability Analysis
In terms of statistics, the analysis of the total tonnage of crude oil shipment, oil tanker calls and gross registered tonnage of oil tanker calls at the operational crude oil terminals revealed that the total volume of crude oil shipment from various crude oil terminals with an average tonnage of crude oil shipment per oil tanker over the period was 125,784 tonnage. The crude oil terminals recorded a total of 10,376 oil tanker calls or an annual average of 798 oil tankers calls during the same period. Therefore, assessing the vulnerability of the landscape to oil spills is information critical to petroleum industry emergency response planners. In an emergency event, information on the potential risk for oil spills and the sensitivity of landscapes to oil spills are required for rapid production of response information. Compliance with existing guidelines for conducting Environmental Impact Assessment in the Oil and Gas Sector which states that construction of product depots for storage of petroleum products (AGO,PMS,DPK etc.) which have a combined storage capacity of 60,000 barrels or more be located 3km from any commercial , industrial or residential area was analysed. To do this, a buffer distance of 3km was created around all oil facilities and jetties in the area. Total surface area susceptible to oil spill was computed as 74.611 sqkm.
In Nigeria, Geographical Information System, G.I.S. has been used as a tool for monitoring, managing or reducing environmental effects of spills arising from Ports, terminals, Oil jetties and related activities. Accordingly, it provides a means to draw together diverse data sets, analyze and present the results to the user in a manner which could be rapidly assimilated for decision making.GIS also provides a measure of flexibility and timeliness when responding to environmental questions since the GIS data set can be readily updated in the light of new information or changes in environmental conditions.Operational standards should be viewed as being dynamic. Efforts should ensure continuous improvement on what exists. It is thus imperative to recommend that regulations specifically affecting the siting of Oil tank farm storage facilities, maritime and jetty operations as it relates to issues of environmental sustainability and safety of lives and properties be formulated and strictly enforced. Awareness creation on the usefulness of GIS as an integral part of a sound management programme for oil spill needs to be embarked upon. The relevant Agency should ensure this through prompt stakeholders’ engagements. More spill response centres should be established in close proximity to the more hazardous areas.Finally, more funds should be provided by stakeholders in the oil industry for further research in the development and use of GIS oil spill models such as this for the study area. Data directory which will allow for synergy in locating the existing response for better efficiency should be collected and harmonized. The oil industry and related operators should work closely with government agencies, universities and research centers to combat the menace of oil spill incidents.
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