울산 해양 퇴적물의 중금속 오염: 인천, 여수와의 비교를 통한 지역적 특성 분석

Abstract

This study analyzed national monitoring data from 2015 to 2024 to evaluate patterns of heavy metal contamination in sediments and seawater along the industrialized coasts of Incheon, Ulsan, and Yeosu in Korea. Ulsan exhibited notably higher levels of heavy metal contamination in sediment, with median concentrations of Zn (80.4 mg/kg), Hg (0.155 mg/kg), and As (20.4 mg/kg) frequently exceeding the NOAA threshold effect levels (TEL), indicating persistent high-risk conditions. The ecological hazard quotients (HQ_EC50) were significantly higher than those derived from chemical assessments, particularly for Hg (8.00) and As (10.20), underscoring the substantial underestimation of ecological risks when relying solely on chemical criteria. Time-series analysis indicated a significant decline in the concentrations of regulated metals, especially Cu in Ulsan, following targeted pollution control measures, with an annual rate of decrease of -6.21% (p = 0.015). Conversely, concentrations of non-regulated metals such as As (annual increase of 3.92%, p = 0.010) and Cr (annual increase of 1.96%, p = 0.006) continued to rise. Incheon frequently exceeded long-term ecological criteria for Cu in seawater, although Hg concentrations significantly decreased at an annual rate of -8.26% (p = 0.012). Yeosu maintained consistently low and stable levels of heavy metals in both sediment and seawater, reflecting the effectiveness of environmental management efforts implemented in 2012. These findings highlight the critical need for multi-criteria ecological risk assessment frameworks and strengthened management strategies for heavy metals in industrial coastal areas.