Physico-Chemical Quality of Selected Drinking Water Sources in Mbarara Municipality, Uganda

Abstract

The study assessed the physico-chemical quality of selected drinking water sources (springs, boreholes, shallow wells and rainfall) in Mbarara municipality with respect to World Health Organization (WHO) drinking water guidelines and other guidelines in light of the increased anthropogenic activities in the municipality. A total of 70 water samples were collected from purposively selected boreholes, springs, wells and rainwater in Nyamitanga, Kamukuzi and Kakoba divisions of Mbarara municipality with various human activities. The samples were analysed for physico-chemical parameters: Temperature, pH, Dissolved Oxygen (DO), Biological Oxygen Demand (BOD), Total Dissolved Solids (TDS), Electrical Conductivity (EC) and Total hardness using American Public Health Association (APHA) standard methods. The mean temperature and pH ranged between 18.07 °C - 23.45 °C and 5.74 - 7.54, respectively. The mean DO values were found to be between 4.84 and 12.86 mg/l; whereas mean BOD was within the range of 1.83 - 7.71 mg/l. The mean TDS and EC of the water samples ranged, between 33.40 - 569.20 mg/l and 29.30 - 1139.90 μS/cm respectively. Furthermore, the lowest and highest mean total hardness were 70.00 and 264.00 mg/l, respectively. The recorded mean water temperatures for each of the water sources were above the WHO threshold temperature (15 °C) which makes drinking water palatable. Boreholes in Nyamitanga and Shuhaddea Secondary Schools, spring in Kiswahili, well in Kisenyi and rainwater in Mbarara University of Science and Technology (MUST) had mean pH below the WHO minimum guideline value (6.5) hence acidic. Borehole in Nyamitanga secondary school, spring in Kisenyi, shallow well in Nyamitanga and the rainwater in MUST had mean DO values below the WHO range (10 - 12 mg/l). Borehole in Shuhaddea Secondary School and the well in Kisenyi had average BOD values above the range of European Union guideline values (3 - 6 mg/l). TDS and EC of all the water sources were below the WHO maximum guideline limits of 1000 mg/l and 1500 μs/cm respectively. Total hardness was also below the WHO harmless limit of 1000 mg/l. However rainwater in MUST was moderately soft while the other drinking water sources exhibited moderate to full total hardness. The physicochemical parameters of some of the selected water sources in Mbarara municipality have been compromised mainly by the increased human activities especially croplands, latrines, landfills, transportation, animal and municipal wastes at the vicinity of the water sources. Mbarara municipal council should therefore ensure proper sanitation and water safety plans for these drinking water sources to avoid further contamination from the human activities.