Estimating the Distribution of Land-based Marine Debris and Risk Assessment to Sensitive Resources in an Estuarine Ecosystems with high river discharge in South Korea

Marine debris can be classified as either land or marine origin, with more than 8 million tons of land-based debris entering the ocean globally each year. Land-based debris enters estuaries and coasts in large quantities through river systems, which may cause water pollution, damage to aquatic and coastal ecosystems, and marine safety accidents. We applied an integrated approach linking watersheds, rivers, estuaries and oceans to investigate the transport processes of land-based debris into an estuarine ecosystem, and assessed their risk to sensitive resources in South Korea, a country with a monsoonal climate.

Based on the time-series trash data collected at major dams, a model was developed to estimate the amount of land-based debris generated in the watershed. We found that land cover, hydrological characteristics, and socioeconomic factors of the watershed played an important role in the generation of land-based debris. Most of the land-based debris is vegetation wastes and plastics, which tends to be discharged through rivers during the monsoon season when rainfall intensity is high. A particle transport modeling was used to estimate the spread of land-based debris through rivers to the Geum-River estuarine system. The results showed a good agreement with the distribution of marine debris monitoring data. The Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST)-Habitat Risk Assessment model was used to assess marine debris risk to sensitive resources in the estuarine ecosystems. The spatially explicit results of risk assessment provide key information to support marine debris management policies at the national and regional levels.

Acknowledge: This research was a part of the project titled “Development of Smart Technology to Support the Collection and Management of Marine Debris” (grant number 20200594), funded by the Ministry of Ocean and Fisheries (Korea), supported by Korea Institute of Marine Science & Technology Promotion. Also, this research was a part of the project titled “Establishing a smart response platform for marine accidents” (grant number 20220463), funded by the Korea Coast Guard, supported by Korea Institute of Marine Science & Technology Promotion. The project was implemented by the Korea Environment Institute (project 2024-007(R), project 2024-008(R)).