Sources of Water Pollution and Selected Physicochemical Parameters of the Nyakomisaro River in Kisii County, Kenya

Abstract

Water is the most vital natural resource in existence as all forms of life depend on it. However, this resource is constantly polluted by human activities. Pollution of rivers is a big challenge not only in Kisii County but as a Country at large. Purposive sampling was used to identify the study area and random sampling was used to collect questionnaires. Water samples were also collected from the study site and physicochemical parameters were analysed in the laboratory. Primary data was analysed descriptively while laboratory data was analysed descriptively and statistically using t-test. Dumping of liquid and solid waste (37.2%) and farming along the river banks (34.9%) were some of the causes of pollution in River Nyakomisaro. The two main economic activities affecting the river are sand harvesting (30.6%) and farming along the river banks (26.8%). The mean value of COD, BOD, TDS, Do, pH, Ec and Temp in Nyaguru (upstream) sampling points were 74.58±13.88 mg/l, 8.42±0.4 mg/l, 20.25±0.5 N. T. U, 3.75±0.21mg/l, 6.78±0.02, 0.19±0.00 S/m and 22.28±0.37°C respectively and the mean value of COD, BOD, TDS, Do, pH, Ec and Temp in Daraja (downstream) sampling points were 14.33±1.09 (mg/l), 4.92±0.45 (mg/l), 17.5±0.5 N. T. U., 3.65±0.34 mg/l., 6.84±0.02, 0.18±0.00 S/m and 22.98±0.40°C respectively. The concentrations of these physico-chemical parameters except Do and pH showed significant differences among the points (P>0.05). The values of all the parameters were within standards stipulated by World Health Organization except the values of Chemical Oxygen Demand. This also means that this water is not good for drinking and certain protective measures should be taken to ensure that residents depending on the source are not affected by it use. Therefore, community and town residents should be sensitized on the effects of indiscriminate disposal of waste to environment and River Nyakomisaro. Also, there should be a continuous monitoring of the water quality along the river to ensure that water is safe for consumption.