Bacteriological Quality Assessment of Harvested Rain Water Stored in Excavated Tanks in Rural Communities of Ogbadibo Area, North Central Nigeria

Bacteriological quality of harvested rain surface water stored in randomly selected 49 cased and 77 uncased excavated tanks in Ogbadibo area was assessed during the dry season of January to March 2011. Multiple-tube fermentation technique and biochemical tests for identification of bacteria were used. Forty five (91.8%) of cased and 75 (97.4%) of the uncased reservoir water were positive for coliform and non-coliform bacteria, giving a total of 120 (95.2%) out of 126 sampled. Contamination of the reservoirs by bacteria was high throughout the communities, ranging from 94.1% in Orokam to 96.9% in Owukpa. The water quality was bad with most probable number (MPN) index ranging from 28 to above 278. The bacterial species identified and the number of affected tanks were Enterobacter species in 104 (82.5%), Klebsiella species 83 (65.9%), Proteus species 72 (57.1%), Citrobacter species 66 (52.4%), Escherichia coli 29 (23.6%), Salmonella species 15 (11.9%) and Shigella species 11 (8.9%). Every reservoir was contaminated with at least 3 species of the identified bacteria. There is urgent need for public health education, reservoir design for cased elevation and encasement, and stored water treatment to prevent outbreak of water borne diseases. Keywords: Coliform bacteria, tube-fermentation technique, contamination, biochemical test