Quality of packaged drinking water in Kolkata City, India and risk to public health

Abstract

In recent years, packaged drinking water (PDW) has become one of the major sources of drinking water and is very popular among consumers. The study was conducted to assess the bacteriological and physicochemical quality of PDW sold in Kolkata city, India, and its effects on public health. The quality of Indian PDW has been compared with that of Kolkata Municipal Corporation (KMC) supply water. Further, the quality of PDW and KMC supply water has been compared with an average quality of bottled water of some branded companies of advanced countries with respect to relevant Indian and international standards (World Health Organization, IBWA, US FDA and EPA). The samples of 27 types of bottled PDW, 10 types of bubble top can PDW of different Indian brands and 18 samples of KMC supply water have been collected from different locations of the city. Physicochemical and bacteriological parameters of collected samples have been tested at School of Water Resources Engineering, Jadavpur University, as per APHA guidelines and also some parameters have been obtained using different field kit instruments. In the study, no bacteria were found in the entire samples of either PDW or KMC supply water. The study also showed that at least 41% PDW had pH value below 6.5 and was acidic, whereas pH of KMC supply water was within the acceptable range (6.5–8.5). Both types of PDW were found to be soft, containing low concentration of minerals, total dissolved solids (TDS), calcium (Ca) and magnesium (Mg). All PDW showed low TDS values having the averages of 38.26 mg/l (bottled), 24.68 mg/l (bubble top can) and the maximum of 117 mg/l. Similarly, all PDW were found with very low “total hardness (TH)” with the maximum value of 76 mg/l, which is much below the standard limit. Likewise, all samples were also found to have low concentration of calcium (Ca), magnesium (Mg), chloride (Cl−) and negligible concentration of fluoride (F−) compared to bottled water of branded companies of some advanced countries, as per relevant Indian and international standards. On the other hand, municipal corporation supply water samples showed quite higher values of above-mentioned physicochemical parameters satisfying the said standards. Long-term consumption of low mineralised PDW may lead to potential risk on public health, like irritation to mucous membranes, increase in cardiovascular diseases, etc. Under this situation, municipal supply water can be a good alternative for drinking purposes. For this purpose, concerned municipal authorities should carry on regular and proper monitoring of supply water to ensure desired quality and encourage people to use the corporation supply water.