Bacteriological and Physicochemical Analysis of Public Drinking Water Sources in Sokoto Metropolis

ABSTRACT

Bacteriological and physicochemical properties of drinking water (tap, well and borehole) in Sokoto metropolis were investigated to determine the level of contamination and the persistence of target organisms. A total of 270 samples comprising of 90 well water samples, 90 tap water samples and 90 boreholes water samples were obtained from some parts of Sokoto metropolis and analyzed using standard procedures. Total coliform count, heterotrophic plate count, physico-chemical properties feacal-coliform count and the presence of Escherichia coli, Enterobacter species, Bacillus subtilis, Shigella species, Salmonella species, Citrobacter species, Staphylococcu saureus and Bacillus cereus were determined. Biochemical identification showed that out of the 108 confirmed Escherichia coli isolates, 51(47%) were from well water and of the 42 Enterobacter species recovered 19 (45%) were from well water while5 (42%) out of 12 Salmonella species were also recovered from well water. The tap water had 26 (24%) Escherichia coli, 13(30%) Enterobacter, 3 (25%) Salmonella species, 5(71%) Bacillus species and other unidentified organisms while in contrast, borehole water had 31 (29%) Eschericia coli, 10 (24%) Enterobacter, 4 (33%) Salmonella species, 2 (26%) Bacillus and other unidentified organisms. No Vibrio species were isolated in all cases. The molecular analysis showed that out of the 79 isolates identified from biochemical analysis, 40 isolates were further subjected to molecular analysis using microgen GN-ID System (kit method).There were 13 (33%) inactive Eechericia coli, 5 (13%) active Eschericia coli and 10 (25%) were other organisms, while the remaining 12(30%) were not identified. The physicochemical properties show that the highest pH was in borehole water sample (6.73) while the lowest was in well water samples (5.7). The highest Electrical conductivity was in tap water samples (142.67 μs/cm), while the lowest was in well (5.8 μs/cm). The highest value of dissolved oxygen was in borehole water samples (8.83 mg/l) and the lowest was found in tap water samples (3.57 mg/l). The highest BOD was in well water samples (15.57 mg/l) while the lowest was in tap water samples (7.73). Therefore, adequate treatment of all waters and public health education are highly recommended.