PHYSICO-CHEMICAL AND MICROBIAL QUALITY OF BOTTLED DRINKING WATER SOLD IN EMBAKASI CENTRAL, NAIROBI, KENYA

Abstract

The global prevalence of diseases is heavily impacted by the consumption of unsafe drinking water. In Low- and Middle-Income Countries (LMIC), bottled drinking water is among the fastest growing options for seemingly safe drinking water. Convenience and perceived good quality are leading motivators of bottle water use in LMICs, however water quality information for bottled water brands in LMICs remain scarce. The objective of this study was to assess the physico-chemical and microbial quality of bottled drinking water in Embakasi Central Sub-County, Nairobi County, where elevated levels of diarrheal diseases have been documented in recent years. Using a cross-sectional study design, the study assessed 8 commonly consumed bottled water brands purchased from local retail outlets, consisting of 158 water samples collected in duplicate. Laboratory analysis was conducted to assess pH, electrical conductivity, lead, nitrite, nitrate, fluoride, heterotropic plate count (HPC), E. coli, total dissolved solids (TDS), hardness, sulphate, sodium, magnesium, potassium, and calcium. Across all brands, 12% of samples exceeded the national water quality guideline for microbial safety (<1 CFU E.coli/100 mL). Select brands were frequently contaminated with E. coli, with Brands 2 and 5 having 28% and 30% contamination rates, respectively. Additionally, 100% of Brand 5 samples had unsafe levels of fluoride. Overall, one in five samples collected exceeded the accepted thresholds for contaminants of public health concern (fluoride or E. coli). The results of this study reveal poor quality of bottled drinking water in a suburb of Nairobi, presenting a risk to consumers. There is a need to strengthen risk management and oversight of water packaging facilities in this setting.