Abstract
Freshwater salinization is an emerging and largely unregulated threat to drinking water security. We identify three dominant, seasonally distinct sources of rising sodium in a drinking water supply serving 1 million people: (1) road deicers, which elevate reservoir sodium in winter, with detectable impacts at watershed impervious cover as low as 3%; (2) reclaimed water, which increases sodium during summer low flows when dilution is minimal; and (3) the drinking water treatment plant (DWTP), which adds NaOH to neutralize acidity from coagulation and in-reservoir microbial processes. In this social-ecological-technological system (SETS), salinization is tied to population growth, impervious cover, sodium-rich waste streams, nitrogen management, reservoir biogeochemistry, and DWTP operations. Framing drinking water salinization as a SETS challenge integrates behavioral and biophysical drivers with engineering and governance responses, providing a framework for adaptation in One Water systems.
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Data availability
All biophysical and de-identified human subjects research data can be found at the following archive: https://doi.org/10.4211/hs.98063d3cf62844cb966b2f461a47b5f2. Ethical approval for human subjects research was granted by Virginia Polytechnic Institute and State University’s Institutional Review Board (HS #20-648).
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Acknowledgements
Funding provided by U.S. National Science Foundation Growing Convergence Research Program (#2021015, #2020814, #2020820) and a Metropolitan Washington Council of Government award (#21-001). The authors thank Bob Angelotti and Brian Owsenek from the Upper Occoquan Service Authority, Sarah Sivers from the Virginia Department of Environmental Quality, and Reza Ramyar from Prince William County for providing data and valuable feedback on this work.
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Stanley B. Grant conceived the study, developed the methodology, conducted formal analysis, acquired funding, and wrote the original manuscript draft. Shantanu V. Bhide conceived the study, developed the methodology, conducted formal analysis, and contributed to writing the original draft. Anne Spiesman contributed text and assisted with data collection. Shalini Misra contributed text and assisted with funding acquisition. Megan A. Rippy contributed text, assisted with data analysis, and assisted with funding acquisition. Christopher A. Galik contributed text. Thomas A. Birkland contributed text and assisted with funding acquisition. Todd Schenk contributed text and assisted with funding acquisition. Sujay S. Kaushal assisted with funding acquisition. Peter Vikesland contributed to funding acquisition. William Knocke conducted a formal analysis. Admin Husic conducted a formal analysis. Harold Post contributed text and assisted with data collection. Chad C. Oneway assisted with data collection. Greg Prelewicz assisted with data collection. Brian Steglitz assisted with data collection. Bethany Laursen contributed text to the manuscript. Kristin Rowles contributed text to the manuscript. Shannon Curtis assisted with data collection. Ashley Studholme assisted with data collection. All authors contributed to reviewing and editing the manuscript.
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Communications Earth and Environment thanks Miguel Iglesias, Emma Moffett and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Primary Handling Editors: Rahim Barzegar and Martina Grecequet. [A peer review file is available].
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Grant, S.B., Bhide, S.V., Spiesman, A. et al. Social-ecological-technological drivers of freshwater salinization in the Occoquan Reservoir, United States.
Commun Earth Environ (2026). https://doi.org/10.1038/s43247-025-03152-w
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DOI: https://doi.org/10.1038/s43247-025-03152-w
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