Physico-Chemical Quality of Bottled Drinking Water Sold in Zomba City, Malawi

The quality of drinking water is a key priority from a human health perspective. The present study was conducted to assess the physico-chemical quality of bottled drinking water marketed in Zomba City, Malawi. Seven bottled water brands were analyzed for pH, EC, TDS, K, Na, Ca, Mg, NO3-, F-, Cl- and total water hardness using standard methods. The results of the analysis were compared with Malawi Standard (MS) 560 for natural mineral water, MS 699 for bottled water other than natural mineral water, and the World Health Organization (WHO) guidelines for drinking water. The results showed that EC, TDS, Cl-, NO3-, F-, K, Na, Ca, and Mg in all the bottled water brands complied with MS 560, MS 699, and WHO guidelines for drinking water. Further, four bottled water brands had their mean pH below the minimum MS 560 and MS 699 value of 6.5. Comparison of the analyzed water quality parameters with the reported label values showed considerable variation in both exaggeration and undervaluing. This study has also shown that all brands had low fluoride content as compared to recommended levels by MS 560 and MS 699. The paper suggests the need for strict monitoring to check bottled water quality compliance.