• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.340-343
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• 2004

Since the tide embankment construction started in 1991, the coastal environment in and around the Saemangeum area has undergone changes rapidly, there is a need for monitoring the environmental change in this region. Owing to high temporal and spatial heterogeneity of the coastal ecosystem and processes as well as the expense with traditional filed sampling at discrete locations, satellite remote sensing measurements offer a unique perspective on mapping a large region simultaneously because of the synoptic and repeat coverage and that quantitative algorithms used for estimating constituents' concentration in the coastal environments. Thus, the main objectives of the present study are to analyze the retrieved Suspended Sediment (SS) pattern to predict changes after the commencement of the tide embankment construction work in 1991. This is accomplished with a series of the Landsat TM/ETM+ imagery acquired from 1985-2002 (a total of 18 imageries). Instead of a simple empirical algorithm, we implement an analytical SS algorithm, developed by Ahn et al. (2003), which is especially developed for estimating SS concentration (SSC) in Case-2 waters. The results show that there is a significant change in SS pattern, which is mainly influenced by the tide and tidal height after the construction of the embankment work. As the construction progressed, the distribution pattern of SS has greatly changed, and the rate of SS concentration in the gap area of the dyke of post-construction has significantly increased.

• 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 Korean Journal of Pesticide Science
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• v.3 no.1
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• pp.51-56
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• 1999

For the determination of coastal environmental contamination level of benomyl, benzimidazole pesticide, the residue of benomyl in various environmental samples on the Cheju island was monitored in May, August and October 1996, respectively. The residue of benomyl was determined as carbendazim because benomyl was converted to carbendazim (methyl 2- benzimidazolecarbamate) in the environment. The qualified limit detection of benomyl was $0.2{\mu}g/L$ in ocean water and $0.4{\mu}g/kg$ in the solid such as sediment and sea organism by HPLC with UV detector. Benomyl was not detected in any water and sediment. Moreover benomyl was neither detected in seaweed cava(Ecklonia Cava), agar(Gelidium amansii), turban sell(Batillus cornutus) and sea urchin(Anthocidaris Crassispina). Above date suggest that the benomyl used in the Cheju island is not the major source of coastal contamination.

• 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.

• Journal of The Geomorphological Association of Korea
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• v.24 no.1
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• pp.25-38
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• 2017

To investigate the characteristics of sand sediment topography in the Yeonggwang coastal area of Chonnam and to collect evidence of the past extreme events causing coastal flooding, three sites were surveyed among the sediments of Baeksoo-eup Hassari. In this study, the changes of particle characteristics, chemical composition, and the age of deposition of sediments were investigated. The sediments near Baeksoonam Elementary School at the elevation of 10m near the paleo-coastline are estimated to have been deposited at about 3,400 years ago and the grain size of the upper part of the sandy layer is in the range of $2.47-2.11{\varphi}$. The burial age of the sediment layer at Sadeung junction(BSN-B) was about 100 years. Considering the distance from the current coastline, the sands forming the dune are estimated to have been moved or deposited from the nearby area or the other dune on the front side. The mean grain size is observed to be fining upward. Especially, the mean of the upper part is about $2.3{\varphi}$, which is similar to other survey points. The averaged grain size of the lower part of the BSNC (Hasari-1 Gu) was $2.196{\varphi}$ and the upper part was $2.16{\varphi}$. The sorting showed that the upper part was slightly poorer than the lower, and it was difficult to specify the change of the environment. The burial age of the lower layer, which contains shells, was about 300 years. Considering previous studies, this shell layer is presumed to have formed by coastal flooding, such as a storm surge.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.5
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• pp.514-523
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• 2022

Concentrations of perfluoroalkyl substances (PFASs) were measured in seawater, sediment, and biota collected from Gunsan coast, Korea to investigate their occurrence, distribution, and risk of exposure to humans through seafood consumption. The total concentrations of PFASs in seawater, sediment, and biota ranged from 5.97 to 74.9 ng/L, 0.01 to 13.3 ng/g dry weight, and 0.02 to 5.73 ng/g wet weight, respectively. Predominant PFAS compounds differed across matrices, indicating that the distribution of PFASs in multiple environmental samples is governed by their carbon-chain length. The concentrations of PFASs in seawater were significantly negatively correlated with salinity (P<0.01), suggesting terrestrial input (including land-used PFASs) as the major source of PFAS contamination in coastal environments. The estimated daily intakes (EDIs) of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) through seafood consumption were 0.05 and 0.06 ng/kg body weight/day, respectively. The EDIs of PFOA and PFOS measured in this study were lower those the proposed by the United States Environmental Protection Agency and Canada guidelines, indicating limited health risk for Korean population from PFASs through consumption of seafood from Gunsan coastal environment.

• Journal of Environmental Science International
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• v.28 no.10
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• pp.851-861
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• 2019

In this study, we performed a sediment elution experiment to evaluate water quality in terms of phosphorus, as influenced by the dissolved oxygen consumed by sediments. Three separate model column treatments, namely, raw, calcined, and sonicated oyster shell powders, were used in this experiment. Essential phosphorus fractions were examined to verify their roles in nutrient release from sediment based on correlation analyses. When treated with calcined or sonicated oyster shell powder, the sediment-water interface became "less anaerobic," thereby producing conditions conducive to partial oxidation and activities of aerobic bacteria. Sediment Oxygen Demand (SOD) was found to be closely correlated with the growth of algae, which confirmed an intermittent input of organic biomass at the sediment surface. SOD was positively correlated with exchangeable and loosely adsorbed phosphorus and organic phosphorus, owing to the accumulation of unbound algal biomass-derived phosphates in sediment, whereas it was negatively correlated with ferric iron-bound phosphorus or calcium fluorapatite-bound phosphorus, which were present in the form of "insoluble" complexes, thereby facilitating the free migration of sulfate-reducing bacteria or limiting the release from complexes, depending on applied local conditions. PCR-denaturing gradient gel electrophoresis revealed that iron-reducing bacteria were the dominant species in control and non-calcined oyster shell columns, whereas certain sulfur-oxidizing bacteria were identified in the column treated with calcined oyster powder.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.6
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• pp.619-626
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• 2014

In this paper, it was constructed the halophyte Mesocosm experimental which was used tidal flat and dredged sediment as a substrate material. Depending on the vegetation and substrate material of Mesocosm, Mesocosm A(tidal flat sediment + Salicornia herbacea), Mesocosm B (only dredged sediment), Mesocosm C(dredged sediment + Salicornia herbacea). Monitoring was carried out of Warter quality factots(Chemical Oxygen Demand(COD), Total Nitrogen(T-N), Total Phosphorus(T-P), water temperature, salinity), Sediment factors(Chemical Oxygen Demand(COD), Total Nitrogen(T-N), Total Phosphorus(T-P)) and growth of Salricornia herbacea. Habitat Stability Index of vegetation was calculating by using the monitoring results. HSI of Mesocosm C was calculated from 0.87 to 0.95 as compared to the relatively high HSI in Mesocosm A, it was evaluated to be able to be used in the restoration and construction of the coastal salt marsh with dredged sediment.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.1
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• pp.28-39
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• 2019

In the design process of counter measures against the beach erosion, information like the main sediment transport mode and yearly net amount of longshore and cross shore transport is of great engineering value. In this rationale, we numerically analyzed the yearly sediment budget of the Mang-Bang beach which is suffering from erosion problem. For the case of cross sediment transport, Bailard's model (1981) having its roots on the Bagnold's energy model (1963) is utilized. In doing so, longshore sediment transport rate is estimated based on the assumption that longshore transport rate is determined by the available wave energy influx toward the beach. Velocity moments required for the application of Bailard's model (1981) is deduced from numerical simulation of the nonlinear shoaling process over the Mang-Bang beach of the 71 wave conditions carefully chosen from the wave records. As a wave driver, we used the consistent frequency Boussinesq Eq. by Frelich and Guza (1984). Numerical results show that contrary to the Bailard's study (1981), Irribaren NO. has non negligible influence on the velocity moments. We also proceeds to numerically simulate the yearly sediment budget of Mang-Bang beach. Numerical results show that for ${\beta}=41.6^{\circ}$, the mean orientation of Mang-Bang beach, north-westwardly moving longshore sediment is prevailing over the south-eastwardly moving sediment, the yearly amount of which is simulated to reach its maxima at $125,000m^3/m$. And the null pint where north-westwardly moving longshore sediment is balanced by the south-eastwardly moving longshore sediment is located at ${\beta}=47^{\circ}$. For the case of cross shore sediment, the sediment is gradually moving toward the shore from the April to mid October, whereas these trends are reversed by sporadically occurring energetic wind waves at the end of October and March. We also complete the littoral drift rose of the Mang-Bang beach, which shows that even though the shore line is temporarily retreated, and as a result, the orientation of Mang-Bang beach is larger than the orientation of null pont, south-eastwardly moving longshore sediment is prevailing. In a case that the orientation of Mang-Bang beach is smaller than the orientation of null pont, north-westwardly moving longshore sediment is prevailing. And these trend imply that the Mang-Bang beach is stable one, which has the self restoring capability once exposed to erosion.

• ALGAE
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• v.19 no.2
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• pp.129-137
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• 2004

Since cultural eutrophication has the detrimental effects on estuarine and coastal ecosystems, recognition of early stage of nutrient over-enrichment is critical for effective managements of the ecosystems. Since released nutrients into coastal ecosystems are diluted and dissipated through tidal action and rapid uptakes by marine plants, monitoring of in situ nutrient concentrations may not be useful for detecting early eutrophication on coastal and estuarine ecosystems. To develop an effective indicator of cultural eutrophication using marine plants, tissue N content and area normalized leaf mass of eelgrass, Zostera marina were examined in Kosung Bay and Koje Bay on the south coast of Korea from June 2001 to April 2003. Eelgrass tissue N content exhibited obvious seasonal variations. Leaf N content was highest during winter and early spring and lowest during summer. Eelgrass tissue N content was higher at Kosung Bay site, which has higher sediment organic content, than at Koje Bay site. Area normalized leaf mass showed reverse trend of leaf N content, and consequently, eelgrass leaf N content and leaf mass exhibited strong negative correlation at both study sites. The results of the present study suggested that the ratio of eelgrass leaf N content to area normalized leaf mass can be applied to assess environmental nitrogen conditions on the coastal and estuarine ecosystems.