River–estuary–coastal systems are important transitional environments where land-derived particles and associated contaminants are transported, deposited, and redistributed before entering the marine environment. Road dust accumulates organic chemicals from traffic, urban, and industrial sources, and once mobilized by wind or runoff, road-associated particles can enter nearby waters and reach estuarine sediments. Estuarine sediments act as sinks for particle-associated contaminants, preserving chemical signals of surrounding terrestrial, urban, and industrial inputs. Examining road dust, water, and sediments together can therefore link contaminants across their terrestrial sources, transport through the water, and eventual accumulation in sediments, providing a more integrated view of organic contaminant distribution in the estuarine environments. Non-target screening can provide a broader understanding of chemical profiles and help identify unknown or previously overlooked organic contaminants across different environmental matrices, including compounds that are not included in targeted monitoring lists. The Geumgang River estuary in Korea provides a relevant setting for such an approach, as its lower reaches are bordered by urban, industrial, and port areas and have been shaped by an estuary dam that regulates freshwater discharge, influencing the transport and deposition of land-derived particles. We examined organic contaminant composition in road dust (n = 20), water (n = 26), and sediments (n = 14) from the Geumgang River estuary, Korea, using a gas chromatography–time-of-flight mass spectrometry (GC-TOF/MS)–based non-target screening approach. Road dust was considered a potential indicator of terrestrial and road-associated inputs, water was used to represent contaminants transported within the water column, whereas sediments were used to evaluate the accumulation of organic contaminants in depositional environments. This study provides exploratory information on the occurrence and chemical characteristics of organic contaminants in the Geumgang River estuary. Examining multiple environmental matrices together is important for understanding how organic contaminants are distributed and transferred across these systems. These results will improve our understanding of the distribution and potential source-related patterns of organic contaminants among road dust, water, and sediments, and by characterizing a broad range of compounds rather than a predefined target list, may help identify candidate compounds for further investigation and support monitoring and management of emerging contaminants in river-influenced estuarine environments.

Acknowledgements: This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (RS-2025-02263830).