Evaluation of the bacteriological and physicochemical quality of water supplies in Nsukka, Southeast, Nigeria

Abstract

The bacteriological and physicochemical quality of various water samples from bore hole, dug well and spring, collected from ten different locations within Nsukka were determined. Total viable and coliform counts were evaluated using the standard plate count method and the most probable number (MPN) technique, respectively. The physicochemical parameters were analyzed using standard methods. The mean total bacteria count of the water samples ranged as follows: bore hole (0.92 × 10⁴ to 1.41 × 10⁴) cfu/ml, well water (1.80 × 10⁴ to 2.40 × 10⁴) cfu/ml and spring water (0.78 × 10,⁴ to 1.06 × 10⁴) cfu/ml. The mean total coliform count of the samples in (MPN/100 ml) ranged as follows: bore hole (10 to 15), well water (14 to 18) and spring water (8 to 10). The isolated and identified bacteria were Enterobacter spp., Alcaligenes spp., Escherichia coli, Proteus spp., Klebsiella spp., Pseudomonas aeruginosa, Acinetobacter spp., Staphylococcus aureus and Bacillus sp. The physicochemical values of the water samples ranged as follows: pH (5.6 to 6.4), dissolved oxygen (DO) (5.4 to 6.4), biochemical oxygen demand (BOD) (10.0 to 20.4), chloride (1.6 to 2.3) mg L^-1, total hardness (48.6 to 68.0) mg L^-1, total dissolved solids (6.3 to 9.7) mg L^-1, sulphate (2.0 to 3.4) mg L^-1 and nitrate (1.2 to 4.1) mg L^-1. The water supply sources in the present study have good physicochemical attributes for human consumption but the presence of E. coli and other potential enteric pathogens indicated faecal matter contamination of the water implying that they are not suitable for human consumption.

Keywords: Drinking water, bacteriological and physicochemical quality, coliforms