Abstract
To characterize the occurrence levels and distribution of disinfection byproducts in drinking water of Chengdu in China, evaluate health risks to the adult population via oral, dermal, and inhalation exposure routes, and identify key health risk drivers. From 2023 to 2025, water samples were collected from 118 centralized water supply units across 23 districts to detect trihalomethanes and haloacetic acid disinfection byproducts, analyze differences in detection and concentration levels across water periods, regions, and water supply scales, and applied the US EPA health risk assessment model to assess exposure risks of trichloromethane, bromodichloromethane, dibromochloromethane, tribromomethane, dichloroacetic acid, and trichloroacetic acid through oral and dermal routes. All 4464 samples had disinfection byproduct concentrations met national standards, with 100.0% pass rate. Trichloromethane had the highest detection rate (86.0%) and median concentration (9.00 µ g/L). Concentrations of trichloromethane, bromodichloromethane, dichloroacetic acid, and trichloroacetic acid were higher in the wet season than in the dry season. Trichloromethane and bromodichloromethane concentrations were higher in urban versus rural samples, whereas dibromochloromethane and dichloroacetic acid were higher in rural areas. Detection rates and concentrations in large centralized water supply units exceeded those in small units (P < 0.05). The health risk assessment showed that the cumulative non-carcinogenic risk (HI < 1) was within acceptable limits, and the cumulative carcinogenic risk (TCR = 4.15 × 10⁻⁵) fell within the commonly used regulatory benchmark range but warrants continued attention. Trichloromethane contributed the largest share (26.5%). Disinfection byproduct concentrations in Chengdu’s drinking water comply with national standards, and the associated non‑carcinogenic health risks are low. The cumulative carcinogenic risk is within the commonly accepted benchmark range but is sufficiently elevated to justify continued surveillance and source‑control measures, with trichloromethane and trichloroacetic acid as priority compounds.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing interests.
Ethical review
This study involved the collection and analysis of drinking water samples and did not involve experimental animals or direct interventions with human subjects. All data were obtained from the “China Disease Prevention and Control Information System” database, which collects routine drinking water monitoring data as mandated by national regulations. The data were anonymized prior to the analysis and did not include any personally identifiable information. According to Article 32 of the “Measures for the Ethical Review of Life Science and Medical Research Involving Human Subjects” (National Health Commission of the PRC, 2023), research using anonymized information data that causes no harm to human subjects and does not involve sensitive personal information is exempt from institutional review board approvals. Therefore, formal ethical approval was not required for this study.
Additional information
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Supplementary Information
Below is the link to the electronic supplementary material.
Rights and permissions
Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.
About this article
Cite this article
Lan, S., Huang, W., Kuang, D. et al. Monitoring and health risk assessment of disinfection byproducts in drinking water in Chengdu, China, 2023–2025. Sci Rep (2026). https://doi.org/10.1038/s41598-026-51835-x
Received:
Accepted:
Published:
DOI: https://doi.org/10.1038/s41598-026-51835-x
