Challenges in the Era of Globalization - iaabd

Abstract
Land Based Sources of Pollution in Lagos Lagoon
Challenges in the Era of Globalization
Edited by Emmanuel Obuah
Oshisanya, K. I kharphioshi@yahoo.com
Nigeria Institute for Oceanography and Marine Research, Victoria Island, Lagos Nigeria.
Due to lack of recent and detailed scientific data on Lagos lagoon there is an urgent need for a precise qualitative
and quantitative assessment of the significant sources of land-based pollution in the region. In Lagos lagoon the
major source of pollution from land-based activities is constituted by litter, solid wastes, plastics and other marine
debris which threatens marine life, degrades the visual amenities of marine and coastal areas, with negative effects
on tourism and general aesthetics.
The major contaminants originate from various domestic discharges and run-offs (including markets, hospitals, etc.)
as well as industrial facilities (from breweries, food, textile, wood processing), Agricultural run-off, Oil and gas.
The main consequences are public health risks from the presence of sewage pathogens, eutrophication or oxygen
depletion due to excess load of nutrients and organic carbon as well as contamination of the marine and human
organisms through the aquatic food chain the water quality deterioration resulting from the insidious sewage runoff
phenomenon, in particular during the rainy season, posed a major risk to the coastal and marine environment
and to people health. The chronic lack of hygiene in most of these environments results in an increase in the number
of infections among the population, in particular among children, with the result that epidemics of typhoid, hepatitis
and malaria are common.
Introduction
Land-based sources of pollution of the urban area of Lagos are best understood giving an insight into the
structure and uniqueness of the Lagoon. The Lagos lagoon is the largest of the four lagoon systems of the
Gulf of Guinea. It stretches for about 25km from Cotonou in the Republic of Benin to the western edge of
the Niger Delta. The brackish water lagoon subtending the island of Lagos is generally located between
longitude 3” 10’ and 3” 45’E and latitude 6”15’and 6”15’N.
The estimated area of the main body of the lagoon is 150.5km 2 . These wide sheets of shallow water which
cover ancient river beds and creeks extend inland. The tidal range is small, only about 0.6 – 1.2m. The
interconnecting creeks are also very shallow and are sites of active silting and deposition of mud. Lagos,
like any other fast growing cities around the globe, pays the ultimate price; Pollution, due to a new and
trendy disposable lifestyle of the developing and developed countries. With a population just over ten
million is the largest and most industrialized city in Nigeria. Over sixty percent of Nigeria’s industrial
production facilities are located in Lagos. These include over 2000 industries on twelve industrial estates,
five of which contain the majority of large and medium-sized industries. .
The major sources of land based pollution in the city are textiles, food processing, metallurgical
(electroplating), rubber and plastics, pharmaceuticals and chemical industries and paint facilities. With the
exception of the treatment works at Agbara Estate and a few primary treatment facilities located in
industries, almost no wastewater is treated in Lagos. Most surveys show that industries discharge their
liquid effluents through ditches, shallow pits, gutters or trenches which eventually empty into the Lagos
lagoon (FMWH, 1983; Ajao 1990).
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