광양만의 표층 퇴적물의 유기물 함량과 중금속 분포 특성

Abstract

Abstract

To recognize geochemical and sedimentologic characteristics of surface sediments, We investigated the organic matters and the metal elements (Pb, Cd, Cr, Cu, Ni, Co, As, Zn, Fe, Al, Mn) concentrations. Mean grain size values of surface sediments in Gwangyang bay were in the range of 7.23-8.85Ф and consisted predominantly of silt. The water content of the surface sediments exceeded 50% except for some stations. The contents of Ignition Loss (IL), Total Organic Carbon (TOC) and Total Nitrogen (TN) were ranged from 4.3-9.4%, 0.7-2.0% and 0.09-0.24%, respectively. Based on the C/N ratios, the organic matter in the surface sediments of the Gwangyang bay meant terrigenous source that organic matter of the west stations of the Myodo and stations located between Myodo and Yeosu peninsula originating from the nearby land. And the east of the Myodo meant oceanic source that organic matter originating from the ocean because the inflow of sea water was more than the other rgions. The Chmical Oxygen demand (COD) and Acid volatile sulfide (AVS) were ranged from 10.18-41.9 mg O2/g.dry, 0.002-1.074mg S/g-dry, respectively. Heavy metals of the surface sediments in the Gwangyang Bay were high concentrations generally at the stations entering Gwangyang stream, around Yulchon industrial complex and the POSCO. The distribution of heavy metals and organic matter in the study area were considered as lower correlations, also regulated by artificial factors originating from nearby urban areas and industrial complexes. we calculated the enrichment factor (EF) and geoaccumulation index (Igeo) in order to evaluate quantitative contamination of metal elements of sediments. The enrichment of metallic elements relative to Al exceed 1 at the study site, compared to levels in the earth's crust except for Cu, Ni. In addtion, Gwangyang stream flow station was relatively high enrichment factor except for Mn. Both Cr and Mn were relatively high enrichment factors in surface sediments of the POSCO surrounding area. The Igeo class of the Cu indicated 5-6 range showing that Gwangyang stream inflow station and the POSCO surrounding area were a significant level of contamination. Therefore, the sediments in Gwangyang Bay were needed management to identify the contamination paths and the pollution levels of organic matters and metallic elements. Through continuous monitoring for the behavior and the accumulation of pollutants in sediments studies for the underlying factors are needed.