Tracking disinfection by-products in northern Canada: impacts of dissolved organic matter and regional variation.

Herrera Molina, Camilo Andres; Comte, Jérôme ORCID: https://orcid.org/0000-0002-7936-4290; Guilherme, François; Rodriguez, Manual; Moisan, Marie-Ange et Laurion, Isabelle ORCID: https://orcid.org/0000-0001-8694-3330 (9999). Tracking disinfection by-products in northern Canada: impacts of dissolved organic matter and regional variation. Science of The Total Environment . (Non Publié)

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Résumé

The concentration of dissolved organic matter (DOM) is increasing in surface waters globally-a phenomenon known as water browning-that is especially pronounced in northern ecosystems. Browning affects lake mixing, light penetration, oxygen availability, and microbial communities, and also presents new challenges for drinking water safety. In northern communities, where drinking water is often treated without prior DOM removal, chlorination can lead to the formation of disinfection by-products (DBPs), such as trihalomethanes (THMs) and haloacetic acids (HAAs), both regulated in various countries for their potential health risks. In this study, we assessed DBP concentrations in drinking water from eight northern communities located across the Northwest Territories, Nunavut, and Nunavik, and examined their relationship with DOM quantity and composition. Despite the oligotrophic nature of the source waters and their relatively low levels of dissolved organic carbon (DOC < 6 mg L^-1), DBPs were detected in all treated water samples, with concentrations occasionally exceeding Canadian guidelines (up to 109 and 100 μg L^-1, respectively). DBP formation was primarily correlated with DOC levels in source water and, to a lesser extent, with pH and specific DOM components. Regional variations in DOM quality-characterized using optical and fluorescence-based indicators—were also linked to differences in DBP composition. These findings underscore the vulnerability of northern drinking water systems to DBP formation, even under low-DOM conditions, and the importance of DOM quality as a driver of DBPvariability. As climate change intensifies browning through increased precipitation, permafrost thaw, and runoff, the associated risks of DBP formation in remote northern communities are likely to rise, highlighting the need for enhanced monitoring, improved treatment strategies, and long-term planning.

Type de document:	Article
Mots-clés libres:	drinking water security; trihalomethanes; haloacetic acids; arctic lakes; water treatment; chlorination; dissolved organic matter
Centre:	Centre Eau Terre Environnement
Date de dépôt:	29 oct. 2025 19:33
Dernière modification:	30 oct. 2025 17:57
URI:	https://espace.inrs.ca/id/eprint/16723

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