Browsing by Author "Kumie, Abera (Ph.D.)"

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    Assessing the effect of sunlight exposure on the physico-chemical parameters of bottled water in Addis Ababa, Ethiopia.
    (Addis Abeba University, 2020-01) Mulualem, Yibeyin; Kumie, Abera (Ph.D.); Tefera, Yifoker(Ph.D fellow)
    Background: It is a common practice for distributors or trader at sales points leaving bottled water to sunlight before being sold. The exposure of bottled water to sunlight facilitates the formation of toxic substances such as chloroform, haloacetic and terephthalic acid; increase concentration of nitrite; reduce concentration of fluoride and increase turbidity level which has a public health importance. The study on the effect of sunlight exposure of bottled water on its quality is limited in Ethiopia. Objective: To assess the effect of sunlight exposure on physicochemical parameters of bottled water in Addis Ababa, Ethiopia Methods: Experimental observational study design was employed to assess the effect of sunlight exposure on phyisco-chemical parameters of the sampled bottled waters from October 3-30/2020 in Addis Ababa, Ethiopia. Randomly selected bottled water were exposed to direct sunlight for 28 days and the physicochemical parameters of exposed and nonexposed groups were analysed in every seven days. A descriptive analysis was carried out to compare the results against the World Health Organization, International Bottled Water Association and our country standards, and the labelled value. Mean values for physicochemical parameters of bottled water before and after exposure to direct sunlight was compared using paired sample t-test and Wilcoxon signed rank test. Results: The experimental results showed that the values of pH, F - , Mg were decreased from 7.31 to 7.02; 0.20 to 0.15 mg/L, 0.486 to 0.365 mg/L and 3.95 to 3.52 mg/L respectively as sunlight exposure increased. Whereas the level of NO 2 - , TDS and turbidity were increased with increasing sunlight exposure from 0.00 to 0.02 mg/L, 82.82 to 85.24 mg/L and 0.00 to 0.57 NTU respectively. The rest parameters (EC, Cl , and total hardness) were numerically decreased or increased irrespective of sunlight exposure. Statistically significant difference was observed on pH, F - , NO 2 - , and turbidity levels between exposed and non-exposed group only. Conclusion: Sunlight exposure has been shown to increase the value of turbidity, NO , and TDS and decrease the value of pH, F - , Mg 2+ and NO 3 - but it has not exceeded the recommended standards except fluoride and turbidity. The increment or decrement of chloride, EC, hardness and Ca 2+ were not associated with sunlight exposure, instead it may indicates the formation of toxic substances. Recommendations: Proper handling and storage of bottled water have to be given attention to be on the safest side even if exposure didn't exceed most of the permissible value (limit).