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Impact of stagnation and sampling volume on water microbial quality monitoring in large buildings

Émilie Bédard, Céline Laferriere, Éric Déziel and Michèle Prévost

Article (2018)

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Microbial drinking water quality can be altered in large buildings, especially after stagnation. In this study, bacterial profiles were generated according to the stagnation time and the volume of water collected at the tap. Successive volumes of cold and hot water were sampled after controlled stagnation periods. Bacterial profiles revealed an important decline (> 2 log) in culturable cells in the first 500 mL sampled from the hot and cold water systems, with a steep decline in the first 15 mL. The strong exponential correlation (R2 >/= 0.97) between the culturable cell counts in water and the pipe surface-to-volume ratio suggests the biofilm as the main contributor to the rapid increase in suspended culturable cells measured after a short stagnation of one-hour. Results evidence the contribution of the high surface-to-volume ratio at the point of use and the impact of short stagnation times on the increased bacterial load observed. Simple faucets with minimal internal surface area should be preferred to minimize surface area. Sampling protocol, including sampling volume and prior stagnation, was also shown to impact the resulting culturable cell concentration by more than 1000-fold. Sampling a smaller volume on first draw after stagnation will help maximize recovery of bacteria.

Uncontrolled Keywords

Bacterial Load; Biofilms; Colony Count, Microbial; Environmental Monitoring -- methods; Temperature; Water Microbiology; Water Quality

Subjects: 1000 Civil engineering > 1000 Civil engineering
1000 Civil engineering > 1006 Hydrologic engineering
1000 Civil engineering > 1007 Water resources and supply
Department: Department of Civil, Geological and Mining Engineering
Funders: NSERC Industrial Chair on Drinking Water, E. Bedard Vanier Canada Graduate Scholarship
PolyPublie URL: https://publications.polymtl.ca/4773/
Journal Title: PLOS One (vol. 13, no. 6)
Publisher: PLOS
DOI: 10.1371/journal.pone.0199429
Official URL: https://doi.org/10.1371/journal.pone.0199429
Date Deposited: 07 Apr 2021 10:54
Last Modified: 14 May 2023 23:54
Cite in APA 7: Bédard, É., Laferriere, C., Déziel, É., & Prévost, M. (2018). Impact of stagnation and sampling volume on water microbial quality monitoring in large buildings. PLOS One, 13(6). https://doi.org/10.1371/journal.pone.0199429


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