BIOBURDEN (QUALITY) OF DIFFERENT DRINKING WATER SAMPLES

Authors: O. Obire1*, Ramesh.R.Putheti2* and Igoni.O.Abigail1

1Department of Applied and Environmental Biology,Rivers State University of Science and Technology, P.M.B. 5080, Port Harcourt, Nigeria; 2*Member, American Association of Pharmaceutical Scientists,10314-E,Malcolm circle,Cockeysville,Maryland,21030.USA; E-mail: rutwikusa@yahoo.com

The bacteriological quality of various drinking water samples of treated pipe-borne (tap) water, borehole water and well water collected from five (5) locations within “Town” Area of Port Harcourt in Nigeria was evaluated using the standard plate count method and the most probable number (MPN) technique. The temperature and pH mean values recorded ranged from 22.2°C ± 1.48°C to 23.4°C ± 1.95°C and from 7.16 ± 0.055 to 7.36 ± 0.055 respectively. Total aerobic heterotrophic bacterial counts ranged from 7.72 x 10³cfu/ml ± 6.42 x 10³cfu/ml to 12.2 x 10³cfu/ml ± 7.29 x 10³cfu/ml.  While the total coliform and faecal coliform MPN index/100ml ranged from 0 to 1800+ and from 0 to 900 respectively. Analysis of variance (ANOVA) using F-test showed that there was significant difference at p ≤ 0.01 in pH and in faecal coliform MPN and at p≤0.05 in the other parameters determined. The bacteria isolated include Chromobacterium spp., Corynebacterium spp., Escherichia coli, Enterobacter spp., Klebsiella spp., Salmonella spp., Shigella spp., Staphylococcus spp., Streptococcus spp., and their percentages ranged from 5% to 15%. The order of decreasing bacteriological quality of samples is treated tap water > borehole water > well water. The presence of E. coli and enteric pathogens such as Shigella, Enterobacter etc., indicated the contamination of the various water sources with faecal matter implying that they are not suitable for drinking.

Keywords : drinking water, bacteriological quality, coliforms, E. coli, faecal indicator.