Water Quality Index of Distributed Portable Water in the City of Nairobi, Kenya

Abstract

Water quality is one of the indicators that can provide consumer confidence in drinking water distributed in the City of Nairobi. Clean water supply is important to public health hence poor quality of portable water may have negative consequences on general public health. Kenya’s capital, the City of Nairobi, faces several water challenges such as water shortages which could lead to the distribution of substandard portable water. The aim of this study was to investigate the water quality index of portable water distributed in the City of Nairobi. Random sampling was done from twenty eight shops, thirty two households, twenty eight supermarkets and twenty eight water vending stations. The water samples were analysed for colour using spectrophotometry, multiparameter-photometer for the Fluoride test, Silicon ions were tested using the Microwave Plasma Atomic Emission Spectrometer and the Most Probable Number method used to analyse microbial parameters. The study indicated that 12.5 % of the household population living in Nairobi treated their water either by sterilizing or boiling. Portable water from supermarkets and shops recorded nil of Escherichia coli and total coliforms. However, 50 % of water samples from vending stations recorded levels ranging from 1 to 35 MPN/ 100 ml of total coliforms while 18 % recorded 1 to 8 MPN/ 100 ml of Escherichia coli. Moreover, a total population of 6.82 % was found to be taking water with Fluoride above the recommended limits. The recommended Fluoride level in drinking water is 1.5 mg.L-1. The quality of selected parameters was 13.6 % within the set specifications. This means, 86.4 % of the total population in the City of Nairobi is drinking unsafe water. Households should consider boiling water as a means of treatment over chemical sterilization by use of Sodium Hypochlorite.