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Toxicological assessment of potable reuse and conventional drinking waters


Potable reuse, the process of treating wastewater to drinkable standards, offers a reliable and sustainable solution to cities and regions facing shortages of clean water. However, implementation is hindered by perceptions of poor water quality and potential health threats. Herein, we compare water samples from potable reuse systems with conventional drinking waters based on the analysis of Chinese hamster ovary cell cytotoxicity contributed by disinfection by-products (DBPs) and sewage-derived anthropogenic contaminants. In all cases, the cytotoxicity of potable reuse waters is lower than that of drinking waters derived from surface waters. The median contribution to total cytotoxicity was 0.2% for regulated DBPs and 16% for the unregulated DBPs of current research interest. Nonvolatile, uncharacterized DBPs and anthropogenic contaminants accounted for 83% of total cytotoxicity. Potable reuse waters treated by reverse osmosis are not more cytotoxic than groundwaters. Even in the absence of reverse osmosis, reuse waters are less cytotoxic than surface drinking waters. Our results suggest that potable reuse can provide a safe, energy-efficient and cost-effective alternative water supply.

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Fig. 1: Comparison of potable reuse and conventional drinking-water quality.
Fig. 2: Effect of advanced treatment processes on cytotoxicity.
Fig. 3: Contributions of DBPs and anthropogenic chemicals towards cytotoxicity.

Data availability

The datasets generated and/or analysed during the current study are available in Supplementary Tables 18 for (semi-)volatile DBPs and in Supplementary Data 2 for the cytotoxicity bioassay results. Data associated with Supplementary Tables 1–12 are provided in Supplementary Data 1. Source data are provided with this paper.


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This work was supported by funding from the National Science Foundation (CBET 1706154 to W.A.M. and CBET 1706575 to M.J.P.) and the Water Research Foundation (projects 4737 and 5140) to W.A.M. and M.J.P.

Author information

Authors and Affiliations



W.A.M. and M.J.P. designed the project. S.S.L. and W.A.M. collected water samples, measured DBP concentrations and compiled all the data. S.S.L. prepared samples for bioassays. K.B., A.T., E.D.W. and M.J.P. performed the bioassays and data analysis. S.S.L., W.A.M. and M.J.P. wrote the paper.

Corresponding author

Correspondence to William A. Mitch.

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Peer review information

Nature Sustainability thanks Martin A. Page and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary information

Supplementary Information

Supplementary Figs. 1–12, Tables 1–12, Notes 1–9 and references.

Supplementary Data 1

Supplementary Tables 1–12 in Excel format. Basic water-quality parameters, DBP concentrations, summary of cytotoxicity results and description of treatment processes.

Supplementary Data 2

Raw cytotoxicity data for each facility.

Source data

Source Data Fig. 1

CAT and BCAT values plus standard errors

Source Data Fig. 2

CAT and BCAT values plus standard errors

Source Data Fig. 3

CHO cell cytotoxicity values plus standard errors

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Lau, S.S., Bokenkamp, K., Tecza, A. et al. Toxicological assessment of potable reuse and conventional drinking waters. Nat Sustain 6, 39–46 (2023).

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