Urinary tritium concentrations and associated environmental factors among residents living near a nuclear power plant in South Korea: a community-based biomonitoring study.

Abnormally high tritium levels were identified at the Wolsong nuclear power plant (NPP) in 2019, prompting growing concern among nearby residents and public health authorities. The study aimed to investigate tritium internal exposure concentrations among residents and to identify potential internal exposure pathways. A total of 359 residents living within 15 km of the NPP with no occupational history at the facility were enrolled in this cross-sectional study in 2021. Participants were categorized into three distance-based zones. Tritium concentrations were measured in urine samples and local water resources. Statistical analyses were conducted using appropriate parametric tests and linear regression based on log-transformed data. The results showed that residents within 10 km of the NPP exhibited significantly higher urinary tritium levels (mean ± SD: 3.28 ± 2.28 Bq/L; 95% CI: 2.87-3.69; P < 0.05) compared with those living further away. Tap water within 5 km contained the highest tritium levels (6.6 ± 1.6 Bq/L), whereas groundwater in the 5-10 km zone showed elevated levels (2.0 ± 1.9 Bq/L). Participants who had visited the NPP in the previous 2 years presented higher urinary tritium levels than those who had not (P < 0.01). Overall, this study showed that urinary tritium concentrations varied according to residential distance and water resource. All measured urinary tritium levels were far below international safety limits. These findings establish essential baseline data for future surveillance and risk communication on nuclear-related public health issues.