Assessment of the Quality of Bottled Drinking Water Produced in African Cities: A Case Study of Kigali, Rwanda

Abstract

The primordial role of water in the survival of all living organisms is well known. Unfortunately, in most of developing countries including Rwanda, many people still lack access even to basic drinking water services. Consequently, demand in bottled water, which may also come from sources exposed to pollution, keeps on increasing where tap water’s safety is doubted. People are afraid of health problems including death which may be linked to consumption of unsafe water. In that regard, this research was conducted to assess the physicochemical quality of bottled drinking water and tap water produced in Kigali. Hence, seven (7) representative samples of seven certified bottled water brands plus an additional sample of tap water were collected. Samples were subjected to laboratory analysis in triplicates by using standard methods. Spectrophotometer method was used for analysis of nitrate (NO3-), iron (Fe), sulfate (SO42-), chloride (Cl-), potassium (K-), Fluoride (F-), and aluminum (Al3-); titration for total alkalinity (TA), calcium (Ca2+), magnesium (Mg2+); and direct reading on appropriate equipment for pH, turbidity, total dissolved solids (TDS), sodium (Na+) and electrical conductivity (EC). An Analysis of Variance (AoV) was conducted using Statistix 10.0 software. Results showed that the concentration of some parameters were significantly different (p≤0.05) among water brands, those were: pH, TDS, (Fe), (Na), SO4, Cl, TA, Al and EC. In contrast, Turbidity, NO3, Ca, Mg, K, and F were not significantly different (p≥0.05) among brands. Furthermore, all physical and chemical parameters investigated fell within the ranges of Rwanda Standards Board (RSB) and World Health Organization (WHO) permissible limits for safer drinking water, except for pH which violated the lower permissible limit in three brands and the tap water. The results also showed that tap water had good quality as compared to bottled drinking water. However, the research discovered that the concentrations of parameters provided on bottle labels did not match with laboratory results in most of the cases. Companies were recommended to update their labels periodically. The study finally concluded that the overall quality of bottled drinking water produced in Kigali and tap water supplied by WASAC meet the standards of safety for human consumption.