Assessment of seasonal variations in surface water quality characteristics is an\nessential aspect for evaluating water pollution due to both natural and anthropogenic\ninfluences on water resources. In this study, temporal variations\nof water quality in river Rwizi section within Mbarara municipality, Uganda,\nwere assessed using multivariate statistical methods. This river section is a\nmajor source of water for the inhabitants of Mbarara municipality. Water\nsamples from five sites were analyzed for physicochemical parameters such as\npH, EC, turbidity, temperature, TSS, TDS, alkalinity, salinity, colour, NH3-N,\n24\nSO âË?â?? , total hardness, BOD, COD, DO, Ca, Mg, Fe, and Mn. About 50% of\nsites recorded colour above 800 Pt Co, 60% of sites recorded turbidity above\nmaximum permissible limit of 100 mg/l, attributable to erosion and mineral\nmatter. pH for dry season ranged between 6.5 and 8.5 whereas for rainy season\nwas below 6.0. All study sites recorded total Fe above 0.3 mg/l and Mn\nbelow 0.5 mg/l, attributable to chemical weathering of host rock materials as\nwell as from industrial effluent. About 60% of sites recorded COD above 100\nmg/l, 40% and 80% of study sites showed BOD above 50 mg/l in dry and rainy\nseasons respectively. Hardness ranged between 50 and 100 mg/l indicating\nthat the water is moderately soft. Colour, turbidity, alkalinity, TSS, TDS, salinity,\npH, hardness, Fe, Mn, NH3-N, BOD, COD, and DO were higher in\nrainy season, as a result of erosion, discharge of domestic and industrial waste.\nMg, Ca, and 24\nSO âË?â?? were higher during dry season due to high evaporation of\nwater from the river. PCA/FA determined that 81.2% of the total variance was\nexplained by the first factor for the dry season and 69.2% for rain season.\nThese results revealed that water pollution resulted primarily from domestic\nwaste water, agricultural runoff and industrial effluents.
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