Assessing the effect of sunlight exposure on the physico-chemical parameters of bottled water in Addis Ababa, Ethiopia.
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Date
2020-01
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Abeba University
Abstract
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).
Description
Keywords
Bottled water ,sunlight exposure