The River Pollution Profile for Mbagathi River

In recent times, Nairobi Rivers have become vulnerable to pollution due to increased
urbanisation. Despite the potential health hazards that the pollution of water bodies has for
persons who use the water bodies, river pollution still persists. Mbagathi River is one of the
Nairobi Rivers whose pollution levels have increased overtime due to various human activities
along its catchment area as a result of urbanisation. This is the same case for most rivers that
traverse towns, cities or other urban areas. Discard of wastes from the towns or urban areas is a
common scenario especially where the necessary sanitation infrastructure and waste disposal
mechanisms lack.
The project was based upon field and laboratory experiment techniques. It involved collecting
samples and testing various water quality parameters for the river water such as temperature,
hydrogen ion concentration, total suspended solids, dissolved oxygen, chemical oxygen demand,
biological oxygen demand, chlorides, nitrates and total coliform counts. The water samples were
taken at three sampling points between Kephis along Ngong Road and Maasai lodge in Ongata

Rongai. This was done to determine the change in the parameters as the river flows through
Ongata Rongai Township which is responsible for the river pollution. The values obtained were
then compared to those recommended by various water quality standards to determine whether
they fall within the recommended values. This was done for effluent standards and for sources of
domestic water standards.
Pollution of the river was found to increase downstream. Minimal pollution was noted upstream
before entry to Ongata Rongai. However, water quality had deteriorated before the river’s entry
to Nairobi National Park which borders Ongata Rongai. This is an indication that Ongata Rongai
Township is indeed responsible for pollution of Mbagathi River. Pollution of the river was found
to be mainly due to human activities. Such activities are washing of clothes and motorcycles into
the river, uncontrolled disposal of solid wastes and release of raw sewerage into the river. Other
minor causes include are surface run off and agricultural activities.
Although the level of pollution has not yet reached a point to detrimental effects to public health,
appropriate measures have to be taken to control pollution hence improve the water quality in the
river. Public awareness campaigns should be conducted in the area to educate and sensitiz

river. Public awareness campaigns should be conducted in the area to educate and sensitize the
residents on the need to s
sanitation infrastructure and waste disposal mechanisms should be enhanced in order to ensure
good healthy environments in the home, neighborhood and community levels.


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