Microbial and Physical Chemical Indicators of Groundwater Contamination in Kenya: A Case Study of Kisumu Aquifer System, Kenya

Abstract

Safe water of adequate quantity, and dignified sanitation, is vital for the sustenance of a healthy and productive human population. In the recognition of this, the United Nations formulated the Sustainable Development Goal No. 6 to ensure access to safe water and sanitation by all by 2030. Actualization of this Goal requires information on the existing status of water resources and sanitation levels. Knowledge on contamination of groundwater is essential to prevent risks to human health. The objective of this study was to determine groundwater contamination in Kisumu, Kenya. A total of 275 water samples were collected from 22 sites within the informal settlements between December 2016 and December 2017. The samples were analysed for bacterial contamination and physical chemical quality. Thermal tolerant coliform bacteria enumeration was used as a proxy to bacteria contamination, and the pH, turbidity, dissolved oxygen, conductivity, salinity and temperature were used as physical chemical indicators of contamination. The results indicate that groundwater in Kisumu hosed coliform bacteria and therefore didn’t comply with contamination limits for domestic water proposed by WHO and local KEBS standards. The results further indicated that the levels of bacteriological contamination vary with water type, shallow well having the highest bacterial loads. The study concluded that there were potential risks to human health due to high content of coliform bacteria. The study attributed the contribution to pit latrines that were present in virtually all compounds. The pit latrines are located close to the water points. The study recommended the definition of minimum distance between the pit latrines and shallow wells to minimize contamination. The low income dwellers should be educated on simple ways of treating drinking water contaminated by microbial to minimize enteric infections.