[Health risk assessment of Pseudomonas aeruginosa in source water of the Yangtze River Basin in China].

Objective: To assess the health risk of exposure to Pseudomonas aeruginosa (P. aeruginosa) via drinking-water-related pathways based on its occurrence in the source water of the Yangtze River Basin in China. Methods: A total of 44 source water samples were collected from 22 water treatment plants located in 11 cities along the Yangtze River in China from June to August 2024 (wet season) and December 2024 to January 2025 (dry season). Based on the quantitative real-time PCR detection and quantitative microbial risk assessment (QMRA) framework, the annual infection risk and disease burden were evaluated for four exposure pathways, including drinking water intake, accidental ingestion during swimming, other unintentional ingestion, and ocular exposure. A sensitivity analysis was conducted to identify the key parameters influencing the risk estimates. Results: The detection rate of P. aeruginosa in the source water was 45.45% (20/44), with a median nucleic acid concentration of 3.15×102 copies/L. The QMRA results showed a median annual infection risk of 2.14×10-7 infections per person per year (pppy) and a median annual disease burden of 9.75×10-9 disability-adjusted life years (DALYs) pppy. Approximately 5.82% of simulated outcomes exceeded the WHO benchmark of 10-6 DALY pppy. Ocular exposure was identified as a major contributor to the overall risk. Sensitivity analysis indicated that the concentration of P. aeruginosa in source water and the log removal value (LRV) of the treatment process were the key parameters influencing the risk estimates. Conclusion: The overall health risk associated with exposure to P. aeruginosa via drinking-water-related pathways in the Yangtze River Basin is relatively low. However, potential risks may still exist in high-exposure scenarios such as ocular exposure.