| Title: |
Risk Assessment of Legionella pneumophila in Drinking Water Distribution Systems |
| Authors: |
LeChevallier, Mark W.; Bartrand, Timothy A.; Clancy, Jennifer L. |
| Contributors: |
Water Research Foundation |
| Source: |
AWWA Water Science ; volume 7, issue 4 ; ISSN 2577-8161 2577-8161 |
| Publisher Information: |
Wiley |
| Publication Year: |
2025 |
| Collection: |
Wiley Online Library (Open Access Articles via Crossref) |
| Description: |
An assessment of the public health risk posed by Legionella pneumophila in public drinking water was performed on a dataset of 9181 samples collected by 57 water utilities. Overall, 109 (1.19%) samples were positive for L. pneumophila , and only 5 (0.054%) were greater than 1 MPN/mL. When detected, 73% of the positive results were < 10 MPN/100 mL, indicating that L. pneumophila levels in drinking water distribution systems are typically very low. Applying a Quantitative Microbial Risk Assessment model to the six utilities with the highest frequency of L. pneumophila revealed that the annual risk of infection was below the 10 −4 level used for controlling microbial contaminants under the Safe Drinking Water Act. Overall, a national estimate of risk for exposure to L. pneumophila from drinking water distribution systems would be exceedingly small (< 1 × 10 −7 annual risk of infection). Even the sample with the highest detected concentration of L. pneumophila (267 MPN/100 mL) was less than a 1 × 10 −4 risk of infection for a single exposure (from a faucet). Despite the low risk levels, the results should encourage water utility managers to continue to monitor for L. pneumophila and implement corrective measures so as to maintain levels below public health thresholds. The results of this study should not promote complacency among water utilities but encourage them to apply best management practices for Legionella control. The USEPA should consider including L. pneumophila testing in the next Unregulated Contaminant Monitoring Rule program so that a more complete assessment can be obtained for L. pneumophila in drinking water. |
| Document Type: |
article in journal/newspaper |
| Language: |
English |
| DOI: |
10.1002/aws2.70028 |
| Availability: |
https://doi.org/10.1002/aws2.70028; https://awwa.onlinelibrary.wiley.com/doi/pdf/10.1002/aws2.70028 |
| Rights: |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
| Accession Number: |
edsbas.C7E2CDDB |
| Database: |
BASE |