BACTERIOLOGICAL QUALITY STATUS OF BOREHOLES WATER IN THARAKA NITHI COUNTY, KENYA

Abstract

Water shortage that is caused by long droughts and higher cost of accessing piped water have forced many households in Kenya to opt for wells and borehole water. Where they are used, boreholes are exposed to contamination by pathogenic microorganisms from nearby toilets, defecation from domesticated animals and surface runoff. Despite of known health concerns of consuming contaminated water, many rural residents still consume borehole water whose portability is not determined and may not meet WHO standards. Thus, this study was conducted in Tharaka Nithi County to assess bacterial quality status of selected boreholes in Maara, Igamba Ngombe and Tharaka Constituencies between April to September 2019. A total of 108 water samples were collected from 36 boreholes. Boreholes in Mukothima within Tharaka area were not collected as the ones accessed were dry at the time of sampling. The samples were analyzed at Chuka University using most probable number methods, Plate count and bacteria species identified using selected biochemical methods. Data (MPN) for total and feacal coliform for different location of study and boreholes were log transformed (log10 (cfu+3) and compared using general linear method in SAS. Significance means were separated using least significant difference post hoc test in SAS version 9.4. Number of bacteria isolated from water samples were also compared using general linear model. Feacal coliform values exceeding WHO recommendation of (0 CFU/ 100 ml was observed in all borehole surveyed. Mean MPN value of 17.5/ 100 ml CFU was observed in Kawangware. Coliform bacteria E. coli, Bacillus spp, Klebsiella spp were isolated in all the water sampled. However, E. coli followed by Bacillus spp were higher compared to the rest of isolates. Occurrence of these bacteria in borehole water put the health of depended consumers at risk of infection.