Physicochemical and microbial quality of bottled drinking water sold in Embakasi Central, Nairobi, Kenya

Abstract

ABSTRACT Bottled drinking water is among the fastest-growing options for seemingly safe drinking water in low- and middle-income countries. However, comprehensive water quality information is rarely made available to consumers. The objective of this study was to assess the physicochemical and microbial quality of bottled drinking water at the point of sale in Embakasi Central sub-county, Nairobi County. Using a cross-sectional study design, we assessed eight bottled water brands purchased from local retail outlets (n = 158 bottles). Laboratory analysis was conducted to assess a range of parameters, including Escherichia coli, heterotrophic bacteria, lead, nitrite, nitrate, fluoride, and pH. Across all bottles sampled, 12% exceeded the national standards for microbial safety (detectable E. coli) and 3% presented a high risk to health (>10 colony forming units per/100 mL for E. coli). Select brands were frequently contaminated, with all samples of Brand 5 having elevated fluoride levels. Overall, one in four samples exceeded national standards for contaminants of public health concern. These findings reveal the poor quality of bottled drinking water in a suburb of Nairobi, presenting risks to consumers. There is a need to strengthen risk management and oversight of water packaging facilities in this setting.