ABSTRACT
Water is an essential resource for life. However, the
activities of humans contribute to the degradation of water and therefore
diminish the availability of water for future generations. Douala, the economic
capital of Cameroon is the most industrialised and most populated town of the
country. Industries that reject their waste water without previous treatment
degrad the river water quality and put the neighbouring populations in danger.
As part of this study, we worked in the catchment area of river Mgoua with a
surface area of 782 ha. The Mgoua river takes rise from a heavily
industrialized zone and receives pollutants from both industrial and domestic
sources.
The objectives of this work were to determine the sources of
pollution of the river, characterize the river, determine the risks the
neighbouring populations are facing due to the pollution of the river and
propose an institutional framework for integrated management of water resources
in the catchment.
Surveys were conducted at the level of the industries and the
river neighbouring households. Samples were taken from the river at five
different points, once a week from April 22 to May 26 2006. These samples were
subject to physico-chemical and bacteriological analysis. A stakeholder
analysis was carried in order to serve as a base for an institutional framework
to an integrated management of the basin.
The survey conducted among 95 waterside households and
industries showed that the origin of the pollution of the river is both
domestic and industrial. Indeed, all the industries (15) except one send out
waste water without appropriate treatment into the river. As concerns the
population, 54% use the river to dispose waste water, 15% use the river to
dispose sewage water, knowing that 53% of households have latrines situated
near the river. Solid household wastes are disposed directly in the river by
47% of households. The neighbouring riversides suffer from, flood, diseases
link to the quality of water, mosquitoes, smell and unhygienic conditions. The
study indicates that about 71% of the population use well water mainly for
cooking, bathing, washing clothes etc; and that diarrhea and malaria are the
most common diseases.
The five sets of sample have shown that the values of the
physico-chemical parameters for each of the sample do not respect the norms
required for surface water (The mean values of chemical oxygen demand and
biological oxygen demand in five days are greater than those of moderately
polluted surface water respectively by 1717% and 736%). The pollution is
significant immediately after the industries. Then we have a mean value of
211mg/l for total dissolved solids (TDS) and a maximum value of 421 mg/l for
the chemical oxygen demand (COD). Downstream, the pollution increase, values
such as 87 mg/l for biological oxygen demand in five days (BOD5), 111mg/l for
chemical oxygen demand (COD), 228mg/l for suspended materials and 211.8mg/l for
turbidity were found.
We propose setting up a management committee of the Mgoua
catchment which will be composed of resource persons in integrated water
resource management. The committee will benefit technically from the services
of the state and will propose possible solutions to ameliorate the quality of
the river and by so doing, improve the quality of life in the catchment. The
forum shall be composed of representatives of all the stakeholders in the
hydrologic system of river Mgoua.
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