Chemical Water Quality of Bottled Drinking Water Brands Marketed in Mwanza City, Tanzania

摘要

Water is a useful resource for domestic, industrial and agricultural purposes and its importance to man cannot be overemphasized due to its essentiality in body metabolism and proper functioning of cells. The present study was carried out to determine the physico-chemical quality of bottled drinking water brands available in retail shops in Mwanza city (Tanzania), and compare with drinking water standards. The results show that water type for different bottled water brands when classified according to TDS ranged from very low concentrations (brands A and B) to low concentrations (brands C, D, E, and F). Based on the classification criteria of total hardness, most brands were considered to have soft water except for brand E which had moderately hard water. The dominant component to all bottled water brands was SO_(2) accounted 48% to 90% of the total major ions, whereas Cl accounted for 8% to 25%. Somewhat high contributions up to 20% was observed for Ca~(2+), while Mg~(2+) was below 9%, and Fe~(2+) and NO_(3-) were below 6%. Brand D has exceptionally high levels for Cl, NO_(3), and Mg~(2+) ions. When compared with Tanzania Bureau of Standards (TBS) and World Health Organization (WHO) guidelines for drinking water, analysed parameters in all brands were within TBS and WHO limit values for drinking water. The study therefore concludes that the analysed bottled water brands are safe for human consumption. However, it recommends other water quality parameters such as microbiological and heavy metal be studied in future.