The Sea Journal of the Korean Society of Oceanography ISSN:1226-2978(Print) 2671-8820(Online) 한국해양학회지 바다

In this study, heavy metal concentrations, contamination levels, and ecological risks were evaluated in stream sediments within the terrestrial watersheds of five special management areas (Lake Shihwa-Incheon Coast, Gwangyang Bay, Masan Bay, Busan Coast, and Ulsan Coast). Fourteen heavy metal elements—V, Cr, Mn, Co, Ni, Cu, Zn, As, Mo, Cd, Sb, Cs, Ba, Pb, and Hg—and conservative elements Li and Cs were analyzed. Shihwa showed the highest average concentration of Ba at 825.3 mg/kg, while Gwangyang, Masan, Busan, and Ulsan showed the highest average concentrations of Mn at 739.5 mg/kg, 893.2 mg/kg, 1023.5 mg/kg, and 585.4 mg/kg, respectively. Regarding enrichment factors (EF), Sb in Gwangyang, Cr, Ni, and Hg in Masan, and Cu, Cd, and Sb in Ulsan exhibited high concentrations attributed to industrial activities. Analysis of the Pollution Load Index (PLI) revealed that five regions recorded values ​​of 1 or higher, indicating widespread pollution; high pollution loads were confirmed at stations near major national industrial complexes and industrial areas, including Ulsan (U10), Masan (M14), Busan (B7), and Shihwa (S8). In the Ecological Risk Index (ERI) assessment, Hg (mercury) and Cd (cadmium), which have high toxicity coefficients, were analyzed as key elements determining the overall risk. In particular, the average Hg ERI in the Ulsan region was 3,723.1, exceeding the “very high” threshold of 320 by tens of times, while the ERI at the Ulsan U10 station recorded a value of over 50,000, indicating a critically detrimental state to the ecosystem.