Bacteriological Study at nrinking Water In Nvala Town For introudtion of pallution

Abstract

Twenty six drinking water sources including 10 dugwells, 10 samples from Nyala Water Net Works, four reservoir tanks, three water taps and three Kiosks , and six pools, three inside and three in the outskirts of the town, were chosen for the study. Water samples from the sources were examined throughout the year, twice in Summer, Autumn and Winter seaons. Standard methods for examination of water were used in the study using faecal indicator bacteria as index for pollution of water with faecal material and hence other dangerous pathogens. MacConkey’s broth was used for presumptive coliform counts, and brilliant green bile_broth for their confirmation and _for that of E. coli. Indole formation in tryphtone water and characteristic growth on eosin methylene blue medium were used for further confrmation of the presence of E.co1i in water samples. Glucose azide broth was used for presumtive presence of E. faecalis, and aesculin glucose azide agar for its confirmation in the water samples. Reinforced closridial meduim g was used for tentative diagnosis of Clostridium perfiingens in water samples as a third faecal indicator, and litmus milk for its confirmation. Tables of Most Probable Number of bacteria per ml of water were used to estimate and was thus used as an indication for the degree contamination of water. I v It was concluded from the study that all water sources in the town were polluted with faecal indicator bacteria specially coliforms,E.c0_li and E. faecalis. Contamination was the heaviest in pools followed by dugwells and the boreholes respectively. This is attributed to several factors including floods, activities of man and animal and their location near lodgings. The degree of pollution also varied from season to season. v