Volume 10, Number 3—March 2004
Research
Legionella Infection Risk from Domestic Hot Water
Paola Borella*
, M. Teresa Montagna†, Vincenzo Romano-Spica‡§, Serena Stampi¶, Giovanna Stancanelli#, Maria Triassi**, Rachele Neglia*, Isabella Marchesi*, Guglielmina Fantuzzi*, Daniela Tatò†, Christian Napoli†, Gianluigi Quaranta‡, Patrizia Laurenti‡, Erica Leoni¶, Giovanna De Luca§, Cristina Ossi#, Matteo Moro#, and Gabriella Ribera D’Alcalà**
, M. Teresa Montagna†, Vincenzo Romano-Spica‡§, Serena Stampi¶, Giovanna Stancanelli#, Maria Triassi**, Rachele Neglia*, Isabella Marchesi*, Guglielmina Fantuzzi*, Daniela Tatò†, Christian Napoli†, Gianluigi Quaranta‡, Patrizia Laurenti‡, Erica Leoni¶, Giovanna De Luca§, Cristina Ossi#, Matteo Moro#, and Gabriella Ribera D’Alcalà**Table 2
Chemical, physical, and microbiologic characteristics of the examined hot water samples
| Characteristic | Mean | SD | Minimum | Maximum | |
|---|---|---|---|---|---|
| Ca (mg/L) |
85.0 |
33.0 |
0.1 |
252.0 |
|
| Mg (mg/L) |
17.6 |
10.6 |
0.1 |
90.1 |
|
| Total hardness (°F) |
28.3 |
11.4 |
0.3 |
100.1 |
|
| Sampling temperature (°C) |
41.9 |
12.4 |
17.0 |
65.0 |
|
| Operating temperature (°C) |
52.9 |
10.0 |
20.0 |
90.0 |
|
| Geometric mean |
Median |
5th percentile |
95th percentile |
||
| Fe (μg/L) |
15.0 |
21.0 |
0.1 |
171.5 |
|
| Mn (μg/L) |
2.4 |
3.0 |
0.1 |
13.9 |
|
| Cu (μg/L) |
11.5 |
14.2 |
0.1 |
87.5 |
|
| Zn (μg/L) |
62.6 |
100.0 |
1 |
776.4 |
|
| Free Cl (μg/L) |
9.2 |
26.4 |
0.0 |
250.0 |
|
| Oxidizability (mg/L O2) |
0.63 |
0.64 |
0.24 |
1.70 |
|
| Pseudomonas spp. (CFU/100 mL)a |
139.2 |
223.6 |
1.0 |
1.0 × 104 |
|
| Total count at 36°C (CFU/mL)a |
98.6 |
95.0 |
3.4 |
1.7 × 103 |
|
| Total count at 22°C (CFU/mL)a | 50.4 | 30.0 | 4.0 | 3.9 × 103 | |
aPositive samples only.
