Physico-Chemical and Microbial Properties of Water from Kiserian Dam and Its Tributaries in Kajiado County, Kenya.
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Date
2024-10
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Kenyatta University
Abstract
In Kenya, water shortages in semi-arid and dry regions, particularly in urban centers, are being reduced by the construction of dams. However, dense populations in such places reduce water quality since there is a greater chance that sources of surface water may be contaminated due to anthropogenic activities. As a result, humans who utilize the water may be exposed to different disease-causing microbial pathogens such as bacteria, protozoans, viruses, and helminthes. Disease outbreaks have been linked to water, particularly in populations living in unhygienic and unsanitary environments. Kiserian water dam is located on the peripheries of Nairobi city in a region with uncontrolled urbanization that exerts pressure on natural resources including the water in the dam. Residents of Kiserian town and the surrounding areas use the water from the Kiserian dam for residential and recreational needs, making it a crucial resource. Despite the importance of the dam as a source of domestic water, the quality of water is not known and whether it is a possible risk for the residents of Kiserian. The objective of this study was to ascertain whether the water complies with global regulatory standards. Samples of water were collected from the dam and the three streams draining into it. At the dam, the samples were collected from the edges of the dam, about 2-3 metres into the dam. This was done all round the dam. Samples from the streams were collected upstream from the dam, at about 10 metres from each collection point. Cumulatively, 60 samples were taken: 30 from the dam and 10 from each of the streams. The samples' physico-chemical characteristics, including temperature, pH, conductivity, and turbidity, were assessed. The results were evaluated in comparison to the WHO and KEBS requirements for drinking water. The microbial quality was determined using the most probable number (MPN) and the presence of E.coli and other pathogenic microbes. To isolate waterborne bacterial pathogens, samples were inoculated in appropriate enrichment and selective media and the recovered bacteria characterized using biochemical tests. The concentration of various heavy metals such as Lead, Cadmium, Chromium Copper and Manganese was determined. Nutrients analyzed in this study included Nitrates, Phosphates and Sulphates. Data was subjected to statistical analysis using IBM SPSS Statistics Version 23 and excel computer application packages. The results revealed that water pH in all the sources was within the guidelines stipulated by WHO and KEBS of 6.5 to 8.5 for potable water. Conductivity in stream B with a mean of 2735±27.94 µS/cm exceeded the WHO and KEBS guidelines of 2500µS/cm. Turbidity from all the sources except stream A with a mean of 3.60±1.48 NTU exceeded the WHO and KEBS guidelines of 5 NTU. Microbial analysis gave a high MPN mean of >2400 was recorded in all Stream B and Stream C, while a low mean MPN of 920 was recorded in the dam and stream A. Therefore, basically, none of the water from these sources was safe to drink, as the MPN exceeded the guidelines stipulated by WHO and KEBS of 0 coliforms/100ml of water. Samples were then put in the proper enrichment and selective media for isolating waterborne bacterial pathogens, and the recovered bacteria were then described using the proper biochemical tests. In all the sampling points, lead and cadmium exceeded the WHO and KEBS guidelines of 0.01mg/L and 0.003mg/L respectively. The nutrients levels from all the sources were within the WHO and KEBS guidelines. This study presents baseline information on water quality for Kiserian dam, and can be used in designing appropriate strategies for pollution reduction.
Description
A Thesis Submitted in Partial Fulfilment of the Requirements for the Award of the Degree of Master of Science (Applied Parasitology) in the School of Pure and Applied Sciences of Kenyatta University, December 2024.
Supervisor
1. Eunice Kairu
2. Lucy Kamau