engleski

The Difference of Water Quality in Permanently vs. Seasonally Used Water Supply Systems

The presence of opportunistic bacteria such as Legionellae in water presents a public health problem especially in accommodation facilities due to the possible risk of infection and development of Legionnaires´ disease. The water quality in hotel water distribution systems (WDS) was monitored during 3 years in order to estimate Legionella pneumophila colonization risk and to determine the difference in Legionellae presence between the all year-round open hotel and the seasonal hotel (open only during the summer months) in an attempt to identify risk factors for Legionella pneumophila colonization in the Split Dalmatian County, Croatia. Furthermore to emphasize the possible impact and the role of metal ions, the iron, manganese, copper and zinc concentrations were monitored in 159 hot water samples taken from 2 hotels in the period from January 2009 to January 2012. The concentrations of metal ions and the presence of Legionella pneumophila were determined by AAS and by the BCYE agar cultivation method, respectively. During this study, the water quality monitoring results were used for detail statistical analyses. The dependence between permanent and seasonally opened systems was investigated and the seasonal variations of Fe, Zn, Mn and Cu in those WDS were observed and correlated with Legionella presence. Differences in metal concentrations between the seasonal and year-round accommodation facilities were evident, and metal concentrations were generally higher in the seasonal hotel. Legionella pneumophila was isolated in 24 out of 77 hot water samples (31.2%) in the hotel opened only during the summer months and in 24 out of the 82 samples (29.3%) in the all year-round open hotel. Higher concentrations of heavy metals observed in samples from the hotel open only during the summer were in accordance with the corrosion of the metal piping system and with the reduced water flow in seasonal systems, which favoured conditions for the growth and breeding of Legionella spp. WDS in hotels can be heavily colonized by Legionella pneumophila and may increase a risk of Legionnaires´ disease for tourists, therefore the monitoring of some water quality parameters could be used for the prediction of possible Legionellae colonisation.

Legionella pneumophila; copper; iron; manganese; zinc; water distribution systems

nije evidentirano