Microbiological quality of drinking water in northern settlements: Influence of source water and treatment processes.

Moisan, Marie-Ange; Laurion, Isabelle ORCID: https://orcid.org/0000-0001-8694-3330; Guillemette, François; Guilherme, Stéphanie; Edge, Thomas A.; Saleem, Faizan; Schellhorn, Herb; Gurney, Kirsty E. B. ORCID: https://orcid.org/0000-0001-8036-4725; Herrera Molina, Camilo Andres et Comte, Jérôme ORCID: https://orcid.org/0000-0002-7936-4290 (9999). Microbiological quality of drinking water in northern settlements: Influence of source water and treatment processes. Science of The Total Environment . (Non Publié)

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Résumé

Northern settlements face unique challenges regarding drinking water quality which may be exacerbated by rising pressures on freshwater ecosystems from climate change. Notably, browning, which results from the increasing addition of organic matter in surface water, could affect drinking water quality. In this study, we assessed the microbiological quality of water from source to tap, in settlements - including hamlets and northern villages - across Nunavut, Nunavik, and the Northwest Territories. We examined the bacterial composition of drinking water and its relationship with dissolved organic matter (DOM) and nutrients to identify the environmental drivers underlying changes in microbiological quality. Our study shows that the bacterial composition of drinking water sources, and consequently of water within the supply system, differs both spatially and temporally across settlements, and is associated with DOM and nutrient composition (dissolved organic carbon, total nitrogen, and proportions of fluorescent DOM components). Bacterial community composition (abundance and taxa) shifted along the drinking water systems, with patterns of reduction, stability, or increase from source to tap depending on the settlement. In some cases, bacterial abundance increased significantly in household taps, raising potential health concerns. Differences in treatment practices between settlements, particularly chlorination levels and the use (or absence) of filtration, influenced bacterial abundance, resulting in heterogeneous assemblages in treated waters. Overall, these findings highlight that drinking water monitoring must be adapted to local contexts and include regular temporal assessments to effectively identify risks related to microbiological water quality, particularly those arising from environmental changes that alter DOM composition.

Type de document:	Article
Mots-clés libres:	climate change; aquatic microbiome; drinking water quality; drinking water supply; northern settlements; dissolved organic matter; bacterial community structure
Centre:	Centre Eau Terre Environnement
Date de dépôt:	29 oct. 2025 19:34
Dernière modification:	30 oct. 2025 18:02
URI:	https://espace.inrs.ca/id/eprint/16724

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