Bacteriological quality of drinking water from wells located near municipal solid waste dumps and liquid waste sites in Zaria, Kaduna State, Nigeria

Abstract

ABSTRACT This study aimed to determine the contamination level, seasonal distribution and the persistence of Salmonella sp, Vibrio cholera, and E. coli in well waters located near municipal solid and liquid waste dumpsites in Zaria, Kaduna State, Nigeria. A total of 186 samples: well water samples (96), soils from waste dump sites (72) and waste water (18), were collected for this study. Samples were plated using freshly prepared molten plate count, Eosine methylene blue agars, poured and swirled properly for a uniform mixture. The presence of E. coli, Salmonella, and Vibrio sp were determined for the two seasons (dry and wet). The bacteria count revealed a significant difference between well waters, soil samples, liquid waste and the control (total plate count - p < 0.005; 0.0001, total coliform count - p < 0.005; 0.0021). All the sampled well water had coliform counts higher than the recommended standard. The counts were higher in the wet season than the dry season. Out of a total of 125 suspected isolates tested, 70 (56%) were positive for Vibrio cholerae, out of this, 38 (54.3%), 28 (40%) and four (5.7%) isolates were from well water, solid waste dumps and liquid waste respectively. Out of the 177 suspected E. coli isolates from well water, solid waste dumps and liquid waste tested, 162 (91.5%) were positive with 82 (50.6%) of the positive E. coli further confirmed to be E. coli 0157:H7. The results showed significant (p < 0.05) statistical difference between the wet and the dry seasons for all the water samples studied and between control and the other well water samples. Adequate treatments of well water, as well as public health education are highly recommended.