ASSESSMENT OF INSTALLATION WATER QUALITY IN AN EDUCATIONAL BUILDING ON THE BASIS OF LEGIONELLA Sp. CONCENTRATION
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Politechnika Lubelska, Wydział Inżynierii Środowiska, ul. Nadbystrzycka 40B, 20-618 Lublin
Publication date: 2017-06-01
Inż. Ekolog. 2017; 3:245-252
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Legionella are known as one of the dangerous water-borne pathogens, causing severe respiratory tract infections. The aim of this study was to assess the installation water quality in an educational building located in Lublin on the basis of Legionella sp. concentration and physicochemical parameters of cold and hot installation water. Samples (n=60) of cold and hot water were collected for testing from the 10 tapping points during three surveys over a period of five months. The test samples were analyzed for the basic physicochemical parameters of the water quality such as pH, electrical conductivity, temperature, hardness, alkalinity, the total carbon content, the concentration of nitrates, chlorides and sulphates. Additionally, the concentration of calcium, magnesium, iron, manganese and zinc were examined. The presence of Legionella in water samples was measured according the standard methods. The quality of the analyzed water did not raise objections and met the criteria of the Ordinance of the Polish Ministry of Health (2015, pos.1989). The only parameter which did not comply with applicable regulations was the temperature of the supply water and return hot water - it was lower than required. Bacteria of the genus Legionella were detected only in the hot water samples from series 1 when the rate of colonization reached the level of 80%. Among the positive samples, 2 contained less than 1000 CFU/100 ml, 4 samples contained 1x103 to 1x104 CFU/100 ml, and 2 samples contained more than 1x104 CFU/100 ml. The maximum number of CFU in a sample was 1.8x104/100 ml. The most dangerous serogroup L. pneumophila sg 1 was not detected in any of the positive isolated samples. All Legionella - positive samples belonged to L. pneumophila sg 2-14. These findings necessitated a corrective action in the form of thermal disinfection system and its maintenance. Its effectiveness was confirmed by the results of the survey of 2 and 3.