Assessment of the Degree of Contamination in Marine Sediments at Cheonsu Bay, West Coast of Korea

Abstract

Yoon, Y.-K.; Lee, S.-W., and Yoon, J.-J., 2021. Assessment of the degree of contamination in marine sediments at Cheonsu Bay, west coast of Korea. In: Lee, J.L.; Suh, K.-S.; Lee, B.; Shin, S., and Lee, J. (eds.), Crisis and Integrated Management for Coastal and Marine Safety. Journal of Coastal Research, Special Issue No. 114, pp. 31–35. Coconut Creek (Florida), ISSN 0749-0208. In this study, 32 bottom sediments (30 sites on the surface and 2 sites in the core) were sampled to determine thedegree of marine sediment contamination in Cheonsu Bay. Cleanup indexes of eutrophication (CIET) and harmful chemicals (CHIC) were calculated to determine whether remediation of contaminated sediment was necessary. Generally, an area with CIET ≥ 6 or CHIC ≥ 2 requires cleanup. In the case of Cheonsu Bay, its CEIT value was six or higher at six sites located in the northern area of Cheonsu Bay. The analysis revealed that there was a significant level of organic matter pollution in this region. However, its CHIC was lower than 2 at all sites, indicating that the level of contamination caused by heavy metal pollutants was not high. Core samples were collected up to a depth of 60 cm from the surface at two sites in which CIET was assessed to be greater than 6. Analysis of the core samples indicated that organic matter contamination was present up to a depth of 20–30 cm from the surface. It was inferred that the polluted matter originated from Bunam Lake and Ganwol Lake, which are located to the north of Cheonsu Bay and have highly polluted water and bottom sediments. The results of this study prove that organic matter contamination because of these freshwater lakes has a continuous effect on the sediments in the inner Cheonsu Bay region. To mitigate the degree of contamination in the Cheonsu Bay area, fundamental countermeasures should focus on the source of terrestrial pollutants.