Abstract

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The study was carried out to isolate and identify Coliform bacteria from well water situated in Lapai metropolis. Fifteen (15)samples of well water, used for domestic purposes were collected from different well water points within Lapai metropolis. Most Probable Number was used for enumeration of Coliform, Cultured on Nutrient agar and Eosin methylene blue (EMB) Agar. The isolates were subjected to series of biochemical tests for possible identification. The physicochemical parameters analyzed were pH, Temperature, and Turbidity. The MPN coliform index per 100ml of the water samples ranged from 0-1100+. The Bacteria isolated from well water samples included, Escherichia coli (26.7 %,) Citrobacter sp (13.3%), Shigella sp (13.3%), Salmonella sp(6.7%), Klebsiella sp (20.0%), Serratia sp (13.3%), and Enterobacter sp(6.7%). The percentage occurrence of the isolates indicated that E. coli was predominant with 26.7%, the least occurrence of the isolates were Salmonella sp, and Enterobacter . sp with 6.7% each. The highest temperature recorded for the samples was 25.8°C, and the least was 20.7°C. The pH of the water samples ranged from 6.48-8.15. The turbidity values of the well water samples ranged from 0-4 Nephelometric Turbidity Units (NTU). From the results obtained, most of the water samples analyzed met World Health Organization standard of 0 MPN index/100ml. However, the few samples observed to harbour contaminations calls for treatment before consumption.

Keywords: Isolation, Coliform bacteria, Well water