Microbial Characterization of Water and Biofilms in Drinking Water Distribution Systems at Sport Facilities

Article excerpt

SUMMARY

The present study investigated the in situ microbial indicators' occurrence in water and biofilm in drinking water distribution systems of sport facilities such as gyms. The presence of Legionella, such as a potential pathogen, was also verified. Water and biofilm were contemporaneously collected and microbiologically analyzed. Few colonies of coliforms were detected in biofilm but not in the corresponding water samples. Conversely, some colonies of heterotrophs were counted at 22 °C in both the 80% biofilm samples and the 53% water samples. Legionella was detected in 29% of the hot water systems, and, in particular, L pneumophila in 21% and L non pneumophila in 9% of the samples. Higher counts were found in biofilm samples.

As it was recommended for swimming pools, it is to be hoped that hygiene risk assessment criteria and safety plans could be also developed for gyms to reduce potential hazards to health for all attendants.

Key words: biofilm, drinking water, gyms, microorganisms, plumbing system, sport facilities

INTRODUCTION

The main challenge for drinking water producers is the preservation of drinking water quality in distribution systems.

The European Union Drinking Water Directive 9 8/8 3 /EC (1) sets out the basic parameters that every water system should strive to achieve in order to provide the cleanest, safest and most reliable drinking water possible. Even if routine monitoring is an essential component of water supply management, it is not enough to protect public health. In fact, it is well known that in all distribution systems the interior pipe walls, storage tanks, sediments, and all the surfaces in contact with finished water are colonized by microorganisms, which can survive, grow, and detach depending on local conditions. Release of microorganisms from surfaces of distribution systems into the bulk water may be one of the causes of microbial contamination, resulting in the deterioration of hygienic quality of drinking water (2, 3). These microenvironments create biofilm that can accumulate microorganisms, segregating and protecting them from the effects of disinfection. They are dynamic in nature, and portions are frequently sloughed off pipe surfaces; as a result, the suspended bacterial counts observed in distribution systems can be often the result of biofilm cell detachment rather than growth of organisms in the water (4-6).

Autotrophic and heterotrophic organisms, bacterial indicators, strict and opportunistic pathogens can colonize biofilms and, after mobilisation into the bulk water phase, can reach consumers. Among the opportunistic bacteria, Legionella within man-made water systems presents a potential health concern, particularly for immuno-compromised individuals. In fact, the design of centralized hot and cold water systems creates conditions that suit the growth of these bacteria (7, 8).

In the most recent years the number of people practising a regular physical activity has greatly increased. As a result, a greater attention is being focussed on hygienic risks associated with use of sport facilities (9, 10) where, healthy and immuno-competent people, as well elders, young children and people following rehabilitative treatments, exercise or swim. To obtain advantages from the physical activity and to prevent adverse effects, sports must be practised in suitable structures under the guide of qualified coachers. Nevertheless in these places, in addition of physical accidents, which represent the most frequent type of injury in sports facilities, health risks can be also linked to the use of hygienic facilities (e.g., bathrooms, showers, sinks). Control and maintenance of water distribution systems is therefore becoming a crucial task in ensuring the high quality of distributed water.

Some studies have been performed on real distribution systems investigating both water and biofilm microbial ecology; however none dealt with water distribution systems in sport facilities, such as gyms. …

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