Assessment of chemical variability of major bottled waters in Sri Lanka

Bottled water is one of the major drinking water sources for travellers in tourist hubs in Sri Lanka. In this study, 32 major bottled water brands sold in the country were analyzed with 19 parameters by means of atomic absorption spectrometer, spectrophotometer and titration. The main objective of the present study is to investigate geochemical variations of Sri Lankan bottled waters in order to identify the main geochemical processes. A comparison of the element concentrations and the legal limits (Sri Lanka, US EPA and WHO) shows that only magnesium level in one brand is above the lower level set by Sri Lankan Standard. According to classifications based on European Union mineral water directive, all the brands indicate low mineral content (TDS 0–150 mg/L) and they are suitable for low sodium diets. Hardness of the water fluctuates within soft water (25 brands), moderately hard water (6 brands) and very hard water (1 brand). Accepted water quality classification systems were used to characterize the different bottled water types. Piper and stiff diagrams were used to establish that the dominant chemical types of the bottled waters are magnesium–calcium–bicarbonate (11 brands), magnesium–calcium–sodium–bicarbonate (9 brands), sodium–magnesium–chloride–sulphate (4 brands) and sodium–chloride–sulphate–bicarbonate (3 brands). According to dietary reference intakes, all the bottled water brands are significantly lower than the recommended human mineral requirements. This means that the bottled waters available in the country are useful for low mineral diets rather than sources for the necessary mineral intake.