Background
Drinking water quality can be deteriorated by microbial and toxic chemicals during transport, storage and handling before using by the consumer. This study was conducted to evaluate the microbial and physicochemical quality of drinking water from bottled water coolers.
Methods
A total of 64 water samples, over a 5-month period in 2012-2013, were collected from free status bottled water coolers and water taps in Isfahan. Water samples were analyzed for heterotrophic plate count (HPC), temperature, pH, residual chlorine, turbidity, electrical conductivity (EC) and total organic carbon (TOC). Identification of predominant bacteria was also performed by sequence analysis of 16S rDNA.
Results
The mean HPC of water coolers was determined at 38864 CFU/ml which exceeded the acceptable level for drinking water in 62% of analyzed samples. The HPC from the water coolers was also found to be significantly (P < 0.05) higher than that of the tap waters. The statistical analysis showed no significant difference between the values of pH, EC, turbidity and TOC in water coolers and tap waters. According to sequence analysis eleven species of bacteria were identified.
Conclusion
A high HPC is indicative of microbial water quality deterioration in water coolers. The presence of some opportunistic pathogens in water coolers, furthermore, is a concern from a public health point of view. The results highlight the importance of a periodic disinfection procedure and monitoring system for water coolers in order to keep the level of microbial contamination under control.
Introduction
Drinking water quality is a worldwide concern and has the greatest impact on human health. Consumption of contaminated drinking water was associated with 80 percent of disease and one third of death in developing countries . Therefore, an essential dasar requirement for health protection is to provide the public with adequate supply of drinking water that is safe.
Advances in water treatment have significantly increased the quality and specially the safety of water. However, drinking water quality can deteriorate by microbial and toxic chemicals during transport, storage and handling before reaching the consumer. Distribution systems, service lines and home devices could influence the quality of drinking water. Water quality in home devices is highly affected by biofilm formation. Prevailing conditions in the devices that influence bacterial proliferation include high surface to volume ratio, absence or very low of chlorine residual and relative long stagnation period.