Control factors and contamination assessment of organic matter in Korean coastal sediments

Using data from the Korea National Marine Ecosystem Monitoring Program (2017–2022), this study investigates the spatiotemporal distribution of organic matter across five ecoregions designated by the Marine Environment Management Act. Three analytical approaches were applied to identify key factors influencing organic matter distribution: (1) correlation with sediment particle surface area and clay content, (2) characterization of organic matter sources, and (3) evaluation of sedimentary productivity. Background concentrations were established for each ecoregion, reflecting their unique sedimentary characteristics. Based on these baselines, contamination trends were found to be decreasing in the Central West Sea and Western South Sea, while increasing in the East Sea, Korea Strait, and Jeju Sea. Despite certain methodological limitations in defining background concentrations and contamination thresholds, this study provides valuable insights into the drivers of organic matter contamination and offers essential baseline data for future environmental assessments and coastal management strategies.