Academic journal article Iranian Journal of Public Health

Assessment of Drinking Water Quality from Bottled Water Coolers

Academic journal article Iranian Journal of Public Health

Assessment of Drinking Water Quality from Bottled Water Coolers

Article excerpt

Introduction

Drinking water quality is a worldwide concern and has the greatest impact on human health (1). Con-sumption of contaminated drinking water was as-sociated with 80 percent of disease and one third of death in developing countries (2). Therefore, an essential basic requirement for health protection is to provide the public with adequate supply of drinking water that is safe (3).

Advances in water treatment have significantly increased the quality and specially the safety of water (4). However, drinking water quality can deteriorate by microbial and toxic chemicals dur-ing transport, storage and handling before reach-ing the consumer (5, 6). Distribution systems, ser-vice lines and home devices could influence the quality of drinking water (5). Water quality in home devices is highly affected by biofilm for-mation (5). 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 pe-riod (7).

Biofilms, which are well organized communities of microorganisms, are wide spread in the nature. They constitute a major problem in many environ-mental, industrial and medical settings (8). The presence of dissolved organic compounds in fin-ished drinking water is responsible for growth of bacteria and colonization of water surfaces (5). Biofilm formation is also a concern from public health because it plays a key role in the persistence of bacteria in water systems and protects the bac-teria from adverse environmental conditions, in-cluding disinfectants. Biofilms could also harbor pathogenic bacteria and support their proliferation which may contribute to the spread of waterborne diseases (9).

The heterotrophic plate count (HPC) is a parame-ter which could reflect the biofilm formation in water systems. It has been widely adopted as a standard and simple traditional technique for mi-crobiological testing and safety management of drinking water (10).

Bottled water coolers are home devices which cool and dispense water. They are widely used in warm climates especially in public places and workplaces. The structure of water cooler could affect the bacterial quality of drinking water. Bac-teria present in drinking water may attach to the bottle and dispenser surface of water coolers and form biofilm.

Chemical water pollution due to leaching of or-ganic compounds from Polyethylene terephthalate (PET) bottles in drinking water is also a globally concern (11, 12). Therefore, bottled water coolers have the potential to release hazardous chemicals to the drinking water.

To our knowledge, very few studies have been conducted on the bacteriological quality of bottled water coolers (13, 14). Levesque et al. found a sig-nificantly higher proportion of water cooler sam-ples resulted contaminated than tap water (13). Aerobic plate count was also higher in coolers compared with spring water used to supply the coolers (14). Similar results have also been re-ported about the microbial quality of drinking wa-ter dispensed from bottleless water coolers (water dispensers) (15-17). In general, the water dis-pensed from water coolers was found to be more contaminated than the water supplied to them.

Given the importance of drinking water safety and identification of potential microbial and chemical pollution sources of drinking water this study was conducted to evaluate the microbial and physico-chemical quality of water from bottled water cool-ers. In particular, we studied some physicochemi-cal factors that might influence the microbial qual-ity of water from water coolers. Since, the bacteri-ological quality of drinking water is highly de-pendent on the bacterial species encountered; the identification of predominant bacteria was also performed.

Materials and Methods

Water samples

A total of 32 drinking water samples were col-lected, over a 5-month period in 2012-2013, from free standing bottled water coolers in office build-ings in the city of Isfahan. …

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