| dc.description.abstract | The Mara River and its tributaries are important, not only ecologically but socially, since they serve as the main source of water for inhabitants living within the basin. However, overdependence on their water resource has initiated concerns pertaining to human health because the two tributaries also serve as receptacles of waste resulting from anthropogenic activities particularly within Mulot and Bomet Towns, which lack waste treatment facilities, resulting in water quality degradation. However, the extent to which the water is polluted with respect to different uses and the spatial variation in pollutant levels, is not clear, which necessitated this study, whose main objective was to determine the influence of anthropogenic activities on water quality of Nyangores and Amala tributaries of the Mara River. The specific objectives were to: observe and describe site characteristics and on-going anthropogenic activities, identify and characterize solid waste resulting from anthropogenic activities and deposited within and along the river channels, determine variations in physicochemical parameters, nutrients, benthic macro invertebrates, and coliform bacterial levels resulting from antrhopogenic activities along Amala and Nyangores tributaries. This was a crossectional study in which eight sampling sites were purposively selected; four along each tributary. On each tributary, three sites (1.5krn apart) were located within the urban areas (Bomet or Mulot) at the upper, middle and lower parts of each town, to effectively capture the influence of anthropogenic activities within the urbanized area on water quality. Also for each tributary, a fourth site was located approximately 20km upstream at a spring draining into the tributary, to act as a control. Site characteristics including on-going anthropogenic activities were observed and recorded, while solid waste was visually identified and categorized. Physico-chemical parameters were determined in situ while water samples for nutrients determination were collected in replicates and analysed in the laboratory following the standard methods outlined by the American Public Health Association. Benthic macro invertebrates were sorted out from sediment samples and classified into taxa. Microbial analysis was performed on water samples using the multiple tube fermentation technique. Analysis of Variance followed by Duncan Multiple Range Test were used to determine variations in water quality parameters between sites along each tributary, while Student's ttest was used to establish differences in solid waste and water quality parameters between Amala and Nyangores tributaries. Regression analysis was used to describe relationships between the predictor and response variables. Results showed that all sites were disturbed by anthropogenic activities, except the upper catchment spring draining into Nyangores tributary, which was protected. Most (96.1 %) of the solid waste encountered was recyclable, with polythene bags being dominant (48.9%). Significantly more (62.4%) waste was recorded along Amala than Nyangores tributary (p=O.031). Dissolved oxygen, conductivity, total suspended solids and total phosphorus varied significantly (p<O.05) between sites, along the two tributaries, while total phosphorus levels were significantly higher along Amala than Nyangores tributary (p<O.02). Total nitrogen levels varied significantly (p<O.OOOI)between sites along Nyangores tributary but, not Amala tributary. Benthic macro invertebrate diversity was significantly higher along Nyangores than Amala tributary (p=O.02), with significant variations observed between different taxa along both tributaries (p<O.OOOI). Only total dissolved solid was predictive of benthic macroinvertebrates. Escherichia coli and total coliform levels varied significantly between sites along Nyangores tributary. However, only total coliform showed significant variation between sites along Amala tributary (P=O.OI2). Total nitrogen, pH and total suspended solids were predictive of E. coli abundance along the Mara River tributaries. Regular monitoring of water quality, maintenance of ecological integrity by controlling anthropogenic activities, proper sanitation and waste disposal practices, protection of water sources and public education with regard to water treatment before consumption are recommended based on the findings from this study. | en_US |
