• Fisheries and Aquatic Sciences
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• v.10 no.2
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• pp.93-101
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• 2007

Concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were determined in marine sediments from Mokpo coastal water of Korea. Total and toxic equivalent (TEQ) concentrations of PCDD/Fs ranged from 19.4 to 175pg/g dry weight and ranged from 0.195 to 2.87 pg WHO-TEQ/g dry weight, respectively. These PCDD/F concentrations were below the safety sediment value (20 pg TEQ/g dry weight) of chronic toxicity. A highly significant correlation between the concentrations of PCDD/Fs and total organic carbon (TOC) in marine sediments was observed. Overall PCDD/F concentrations in the sediments were elevated in rivers and at inner locations close to harbors, indicating that these contaminants derived from local discharges of human activities. PCDD/F concentrations measured in our study were lower than those in several industrialized areas in Korea. Nonparametric multidimensional scaling (MDS) ordination showed that combustion processes from industrial complexes are the major source of PCDD/Fs in Mokpo coastal water.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.3
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• pp.127-133
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• 2009

In order to determine organic carbon oxidation by manganese and iron oxides, six core sediments were obtained in slope and basin sediments of Ulleung Basin in East Sea. The basin sediments show high organic carbon contents (>2%) at the water depths deeper than 2,000 m; this is rare for deep-sea sediments, except for those of the Black Sea and Chilean upwelling regions. In the Ullleung Basin, the surface sediments were extremely enriched by Manganese oxides with more than 2%. Maximum contents of Fe oxides were found at the depth of $1{\sim}4cm$ in basin sediments. However, the high level of Mn and Fe oxides was not observed in slope sediment. Surface manganese enrichments (>2%) in Ulleung Basin may be explained by two possible mechanisms: high organic carbon contents and optimum sedimentation rates and sufficient supply of dissolved Manganese from slope to the deep basin. Reduction rates of iron and manganese oxides ranged from 0.10 to $0.24\;mmol\;m^{-2}day^{-1}$ and from 0.30 to $0.57\;mmol\;m^{-2}day^{-1}$, respectively. In Ulleung Basin sediments, $13{\sim}26%$ of organic carbon oxidation may be linked to the reduction of iron and manganese oxides. Reduction rates of metal oxides were comparable to those of Chilean upwelling regions, and lower than those of Danish coastal sediments.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.4
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• pp.372-389
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• 2008

In this study, we formed a detailed grid at the estuary area of the Nakdong and collected the surface sediments. Particle size analysis and comparison with existing data were conducted to investigate the characteristics of seasonal and long-term changes in the sediments. As a result of investigation, the distribution of the sediments showed a great change per season and was greatly influenced by the quantity of outfall discharge at the Nakdong estuary barrier and the incident wave climate. The sandy sediments showed dominant movement toward the front of Jinwoodo west of the estuary area of the Nakdong due to the influence of the ENE wave, the annually-dominant wave. And the muddy sediments showed deposition by being moved toward the deep open sea along with a current. The present conditions of the sediments at the estuary area of the Nakdong showed great differences from the results of previous studies.

• Journal of Environmental Science International
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• v.31 no.9
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• pp.767-779
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• 2022

In this study, sediment cores were sampled from tidal flats (six sites) in the west and south coastal wetlands, the blue carbon stock in the tidal flat sediments was calculated, and the blue carbon stock characteristics and influencing factors were analyzed. The sediment particle size of the west coastal tidal flats was larger than that of the south coastal tidal flats, and the organic carbon content in the south coastal tidal flats was more than twice that of the west coastal tidal flats. Blue carbon stock per unit area was 28.4~36.8 Mg/ha on the west coastal tidal flats and 69.8~89.8 Mg/ha on the south coastal tidal flats, which was more than twice higher in the south coastal tidal flats than in the west coastal tidal flats. The total amount of blue carbon stock in the tidal flats was the highest in Suncheon Bay tidal flats at 153,626 Mg, and followed by Gomso Bay tidal flats at 141,750 Mg, Hampyeong Bay tidal flats at 58,420 Mg, Dongdae Bay tidal flats at 44,900 Mg, Cheonsu Bay tidal flats at 36,880 Mg, and Jinhae Bay tidal flats at 26,205 Mg. Blue carbon stock per unit area was higher in the south coastal tidal flats, but the total amount of blue carbon stock in the tidal flats was higher in the west coast. The slope of the regression function of blue carbon stock with respect to the organic carbon content in the tidal flat sediments was estimated to be about 0.05 to 0.07, and the slope of the regression function was higher in the west coastal tidal flats than in the south coastal tidal flats.

• Journal of Environmental Impact Assessment
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• v.15 no.5
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• pp.289-297
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• 2006

The study investigates the problems of silt protector used for mitigation measure of suspended sediments (SS) during coastal construction and provides their improvements based on the field investigation and analysis of the environmental impact assessment reports for the coastal development projects of Korea. The field investigation along west, east and south coasts of Korea reveals a variety of problems in the installation and management of silt protector solely used for the SS mitigation in Korea. Major problems include installation itself, low cost and quality of silt protector, and maintenance. These problems superimpose the effectiveness of silt protector in mitigating coastal environment impact. The present study provides the specific guideline on the project type needed for the installation of silt protector, installation standard and planning, maintenance and management. The study also suggests new mitigation options such as environmental window to limit the construction period and environmental dredger to compensate for the deficits of silt protector.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2002.05b
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• pp.344-345
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• 2002

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.3
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• pp.159-165
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• 2012

In this study, a series of deposition tests have been performed using an annular flume and depositional parameters of natural cohesive sediments have been estimated domestically for the first time. The natural cohesive sediments for deposition tests have been collected from Kwangyang Bay and total 18 deposition tests have been carried out on different bed shear stress respectively but with the same initial concentration. Test results for natural cohesive sediments of Kwangyang bay show that minimum bed shear stress ${\tau}_{bmin}$, standard deviation ${\sigma}_1$, and time scale parameter $({\tau}_b^*-1)_{50}$ are $0.11N/m^2$, 0.68 and 0.85, respectively. Through the comparison with results of previous studies for other sediments, the results of this study are shown to be good enough to verify.

• Journal of Microbiology and Biotechnology
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• v.26 no.5
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• pp.883-890
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• 2016

Marine sediments are a microbial biosphere with an unknown physiology, and the sediments harbor numerous distinct phylogenetic lineages of Bacteria and Archaea that are at present uncultured. In this study, the structure of the archaeal and bacterial communities was investigated in the surface and subsurface sediments of Jeju Island using a next-generation sequencing method. The microbial communities in the surface sediments were distinct from those in the subsurface sediments; the relative abundance of sequences for Thaumarchaeota, Actinobacteria, Bacteroides, Alphaproteobacteria, and Gammaproteobacteria were higher in the surface than subsurface sediments, whereas the sequences for Euryarchaeota, Acidobacteria, Firmicutes, and Deltaproteobacteria were relatively more abundant in the subsurface than surface sediments. This study presents detailed characterization of the spatial distribution of benthic microbial communities of Jeju Island and provides fundamental information on the potential interactions mediated by microorganisms with the different biogeochemical cycles in coastal sediments.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2003.08a
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• pp.353-358
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• 2003

As fur quantitative evaluation of the amount of sediments released into the ambient waters by various works fur coastal development, the instrument and method of the measurement of suspended sediment concentration (SSC) are critical for estimating the efficiency of a silt screen to reduce the spreading of sediment plumes generated by coastal works. (omitted)

• Ocean and Polar Research
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• v.29 no.4
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• pp.379-389
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• 2007

This paper presents an attempt to determine natural background levels of heavy metals which could be used for assessing heavy metal contamination. For this study, a large archive dataset of heavy metal concentration (Cu, Cr, Ni, Pb, Zn) for more than 900 surface sediment samples from various Korean coastal environments was newly compiled. These data were normalized for aluminum (grain-size normalizer) concentration to isolate natural factors from anthropogenic ones. The normalization was based on the hypothesis that heavy metal concentrations vary consistently with the concentration of aluminum, unless these metals are of anthropogenic origin. So, the samples (outliers) suspected of receivingany anthropogenic input were removed from regression to ascertain the "background" relationship between the metals and aluminum. Identification of these outliers was tested using a model of predicted limits at 95%. The process of testing for normality (Kolmogorov-Smirnov Test) and selection of outliers was iterated until a normal distribution was achieved. On the basis of the linear regression analysis of the large archive (please check) dataset, background levels, which are applicable to heavy metal assessment of Korean coastal sediments, were successfully developed for Cu, Cr, Ni, Zn. As an example, we tested the applicability of this baseline level for metal pollution assessment of Masan Bay sediments.