Evaluation of Bacteriological Quality and Physicochemical Parameters of Drinking Water from Water Vending Machines in Dar es Salaam Region, Tanzania

Abstract

The usage of water from water vending machines has spread in both 
developed and developing countries.  Despite their popularity, 
various studies documented on low quality of drinking water from 
water vending machines. The present study aimed to determine 
physicochemical (pH,  electrical conductivity (EC), Total Dissolved 
Solids (TDS), turbidity, Chloride, Nitrate, Sulphate, Phosphate , 
Calcium carbonate) and bacteriological (E.coli bacteria and total 
coliform) parameters of drinking water in selected parts of Dar es 
Salaam region, Tanzania.  Nine water samples from randomly selected 
water vending machines were collected and tested for 
physicochemical and bacteriological parameters. The pH, electrical 
conductivity (EC), and total dissolved solids (TDS) were measured 
using a multiparameter meter. Turbidity was determined using a 
turbidimeter, while Nitrate, Chloride, Phosphate, Sulphate, and 
Calcium carbonate were analyzed using a spectrophotometer. 
Bacteriological analysis, including E. coli and total coliforms, was 
conducted using cultural and biochemical methods. The average 
results of the physicochemical tests were as follows: pH 7.32, 
electrical conductivity 969 mg/L, total dissolved solids 506 mg/L, 
turbidity 1.84 NTU, Chloride234.90 mg/L, Nitrate 3.3 mg/L, Sulphate 
183 mg/L, phosphate 0.39 mg/L, and calcium carbonate 262 mg/L. 
Physicochemical results of tested samples were suitable for drinking 
and met World Health Organization (WHO) and   Tanzania Standards 
guidelines for drinking water.  For total coliform count, the majority 
of water samples (78%) were excellent while for Escherichia coli all 
samples (100%) were excellent. Therefore, the study concluded that, 
water from water vending machines is fit for human consumption. In 
order to safeguard public health, the study recommends public 
awareness, regular water testing and monitoring its quality.