Quality assessment of drinking water from different sources in Lafia, Nassarawa State, Nigeria
One hundred and twenty four (124) samples of drinking water from different sources in Lafia and its environs were investigated during the months of February to June 2008. The city and its environs were divided into seven zones and samples of water collected from each zones analyzed for physical and microbial quality. The water sources included hand dug wells, boreholes, streams a river. Treated pipe borne water, sachet water and water sold in open containers were also investigated. Standard plate count technique, multiple tube fermentation technique, and membrane filtration technique were employed in determining the microbial quality of the water. The study showed uniform temperature range of 27.5 to 320C in all the zones. The pH at all the stations ranged from 4.9 recorded for Ombi stream to 6.9 recorded for hand dug well from zone C and were within the acceptable standard range for drinking water. Color values range from 6 to 25 hazen, while turbidity ranged from 1.5 NTU for sachet water to 15 NTU for River Amba. The bacterial counts revealed total heterotrophic bacteria range of 12 cfu/ml to too numerous to count. Coliform were present in all sources except sachet and borehole water. E. coli, Aerobacter aerogenes and fecal streptococci were present. E. coli counts of 8 cfu/ml were obtained in hand dug well and 61 cfu in Ombi stream. Yeast (Candida spp), filamentous fungi, the protozoa (Amoeba spp and Paramecium spp), algae, particularly Spirogyra spp were detected in hand dug wells, the three streams and River Amba. The detection of these organisms in dinking water is an indication of the unsuitability of the water sources. Protection of water sources, regular monitoring of drinking water supplies and enforcement of good sanitation habit are recommended for the study area.
Keywords: Drinking water, bacterial count, coliform, heterotrophic bacteria, microbial quality