Onesmus Nzung’a Sila of the Department of Applied Sciences, Machakos Technical Institute for the Blind, Kenya recently evaluated the Physico-chemical and bacteriological quality of water sources in rural African settings using Kenya as a Case study.
Water sources namely, rivers, dams, furrows, springs, wells, boreholes and rainwater were analyzed for selected physicochemical properties that included: pH, total alkalinity, dissolved oxygen (DO), turbidity, color, electrical conductivity (EC) and salinity, and screened for pathogenic bacteria (Total coliforms, E. coli, Shigella, Salmonella, V. cholerae, Klebsiella, S. faecalis, C. perfringens) to ascertain if the water met the required healthy standards.
The physico-chemical characteristics investigated and bacterial load obtained were examined, equated and validated as per Kenya Bureau of Standards (KEBS) and the adopted World Health Organization (WHO) maximum guideline limits for potable water. Results revealed that parameter levels of mean turbidity (0.78 and 0.65 NTU) and color (0.0 mg pt L−1) in borehole and rainwater did not exceed the maximum permissible level.
The results analysis of color, temperature and conductivity found no significant differences (P > 0.05) while there was a significant difference in mean values of salinity, alkalinity, DO, turbidity, among water sources (P < 0.05). Presence of total coliforms (mean range, 10–23,830 CFU/ 100 mL), Escherichia coli (mean range, 10–3480 CFU/100 mL), Vibrio cholera, Shigella sp., Salmonella sp., Klebsiella sp., Streptococcus faecalis and Clostridium perfringens were detected in the water sources. The pathogenic bacteria screened were all detected in Athi and Kauthulini Rivers; hence these were the most polluted water sources. Shigella was found to be the most dominant pathogen occurring in all sampling sites except in borehole and rainwater.
Borehole and rainwater was found to be the safest in terms of physicochemical properties and bacteriological quality. The study concludes that most water sources in tropics do not meet the potable water standards according to KEBS and WHO; hence they can be potential sources of waterborne diseases.