• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.2
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• pp.212-223
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• 2022

For the remediation and restoration of contaminated sediment at the West Sea-Byeong dumping site, dredged materials was dumped in 2013, 2014, 2016, and 2017. The physicochemical properties and benthic fauna in surface sediments of the capping area (5 stations) and natural recovery area (2 stations) were analyzed annually from 2014 to 2020 to evaluate the capping effect of the dredged materials. The natural recovery area had a finer sediment with a mean particle size of 5.91-7.64 Φ, while the sediment in the capping area consisted of coarse-grained particles with a mean particle size of 1.47-3.01 Φ owing to the capping effect of dredged materials. Considering that the contents of organic matters (COD, TOC, and TN) and heavy metals in the capping area are approximately 50 % lower (p<0.05) than that in the natural recovery area, it is judged that there is a capping effect of dredged materials. As a result of analyzing macrobenthic assemblages, the number of species and ecological indices of the capping area were significantly lower than that of the natural recovery area (p<0.05). The number of species and ecological indices at the capping area were increased for the first four years after the capping in 2013 and 2014 and then tended to decrease thereafter. It is presumed that opportunistic species, which have rapid growth and short lifetime, appeared dominantly during the initial phase of capping, and the additory capping in 2016 and 2017 caused re-disturbance in the habitat environment. In the natural recovery and capping areas, Azti's Marine Biotic Index (AMBI) was evaluated as a fine healthy status because it maintained the level of 2^nd grades (Good), whereas Benthic Pollution Index (BPI) remained at the 1^st and 2^nd grade. Therefore, capping of dredged materials for remediation of contaminated sediment in the dumping site has the effect of reducing the pollution level. However, in terms of the benthic ecosystem, it is recommended that the recovery trend should be monitored long-term. Additionally, it is necessary to introduce an adaptive management strategy when expanding the project to remediate the contaminated sediment at the dumping area in the future.

• The Journal of Fisheries Business Administration
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• v.40 no.3
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• pp.29-49
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• 2009

There are various types of predictable economic benefits to restoring beneficial uses from contaminated marine sediment cleanup. These benefits can be derived from reduction in aquatic animals died or infected, increase in their consumption recovery, increase in tourism including recreational fishing, reduction in human health risk, increase in amenity and aesthetics, increase in ecosystem integrity, and so on. The paper focuses on estimating the net increase in value for producers and consumers from producing and consuming those fish due to the pollution reduction of marine contaminated cleanup project. Almost Ideal Demand System(AIDS) is employed for estimate of the demand for fish, and the production cost function for fish are determined using market data. The result shows 10.8 billion won per year for economic surplus to the net increase for producers and consumers.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.12
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• pp.851-857
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• 2014

Treatability of heavy metals in marine sediments contaminated with mainly organic matter was investigated on the basis of washing technology using oxidizers and surfactants. Sediment samples were collected at N area which expected for remediation project of contaminated marine sediment. For additives, hydrogen peroxide ($H_2O_2$) and Tween-80 were used at oxidizer and nonionic surfactant, respectively. In experiments, sediments was mixed with sea water at the ratio of 1 : 3 than $H_2O_2$ (1 M, 3 M, 4 M, 5 M) and Tween-80 (0.05%) were added. Samples were gathered at following reaction time (10, 20, 30, 40, 50, 60, 70, 80 min and 24 h). Total Organic Carbon (TOC) was 55.2% at the conditions of 5 M $H_2O_2+0.05%$ Tween-80 24 h. Hence total heavy metals were Cu 29.5%, Zn 42.3%, Cd 73.0% and bioavailable heavy metals were Cu 60.0%, Zn 77.7%, Cd 90.2% at the conditions of 5 M $H_2O_2+0.05%$ Tween-80 10 min. The correlations for between bioavailable metals (Cu, Zn, Cd) and TOC were significant (Cu, Zn, Cd; $r^2=0.94$, 0.85, 0.69, respectively).

• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.3
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• pp.171-180
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• 2013

Even though styrofoam buoys represent a large portion of beached marine debris in Korea, efficient government actions have been lacking to address them. Three participatory workshops were organized from 2010 to 2012 to develop policy measures to manage styrofoam buoy marine debris. The first workshop held in 2010 was organized in order for workshop participants to understand and share the styrofoam debris issue. Participating stakeholders suggested policy measures to address styrofoam debris through brainstorming in the second workshop in 2011. In the third workshop organized in 2012, the analytic hierarchy process (AHP) was used to set priorities for 16 selected policy measures. A total of 56 people participated in AHP, and answers of 40 participants that passed the consistency test were analyzed. 'Beach cleanup by public works program' ranked highest in priority, followed by 'Development of alternative buoy and aquaculture technologies'. Other research projects also ranked high in priority. Feasibility of policy measures was considered the most important criterion in the priority setting, followed by effectiveness, efficiency, and acceptability. This study demonstrated that participatory workshops in which diverse stakeholders take part in could provide a valuable tool in developing practical policy measures on styrofoam buoy marine debris.

• Journal of Navigation and Port Research
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• v.41 no.4
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• pp.195-206
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• 2017

In situ capping technology for marine sediment pollution control has never been applied in South Korea. In this study a pilot project for the capping was carried out in Busan N Harbor. Pipeline and clamshell capping technologies were implemented for the pollution control. Changes of capping shapes, sediment contamination, and the time and costs required for the two constructions were compared. Both the pipeline and clamshell technologies were found to satisfy the target thickness of 50 cm on average. However, the pipeline method did not operate sensitively in terms of change of the sea floor topography, resulting in an uneven shape and a thickness. Organic carbon and ignition loss quite decreased after the pipeline or the clamshell capping while pH showed no significant change. Organic and residual fraction of Cd, Ni, and Zn in the sediments appeared to decrease after all cappings. The pipeline method took a construction time four times as much as the clamshell method. The clamshell method was demonstrated to reduce the construction cost by about 40% compared with the pipeline method. However, a monitoring for all the parameters needs to be conducted at least two years in order to better evaluate an efficiency of the pollution control by these capping constructions.

• Journal of the Korean Society for Marine Environment & Energy
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• v.2 no.1
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• pp.26-33
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• 1999

Coastal sediments in polluted areas adsorb many hydrophobic pollutants such as PCBs. During environmental remediation projects like dredging, they can be resuspended and transported to less polluted areas. To assess the environmental impact, the author previously developed a mathematical model that can simulate the changes of particle size distribution (PSD) due to sedimentation, vortical dispersion and coagulation. In this research, the simulation results using this model were presented in conjunction with observed PSDs from a 2-m settling column simulating coastal environments. The simulations showed that the model predictions were in fairly good agreement with the observed data (changes of PSDs in terms of depths and times), and that the resuspended sediments coagulated during the vertical transport. So, this study showed that the developed model has a good ability to describe the very complicated phenomena of real aggregation and vortical transport dynamics of coastal sediments with various particle sizes.

• Journal of the Korean Society for Marine Environment & Energy
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• v.1 no.1
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• pp.39-46
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• 1998

This study presents a numerical model that can simulate changes of particle size distribution (PSD) of PCB-contaminated coastal sediments. The developed model has one spatial dimension including sedimentation and vortical dispersion as well as coagulation. The reason for considering the vortical transport mechanisms is to calculate residence time of the particles. Using the model and Initial PSD data based on actual coastal sediments contaminated with PCBs, this study shows results of model simulations. Within 48 hours of the simulation time, the PSD changed significantly and the particles were removed from water in different rates between different particle sizes. It also shows that coagulation can act an important role in this process. The model may be useful in assessing the range of resuspended sediments that can pollute neighboring areas during environmental remediation projects such as dredging.

• Korean Journal of Remote Sensing
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• v.39 no.6_3
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• pp.1747-1761
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• 2023

Wetlands, defined as lands periodically inundated or exposed during the year, are crucial for sustaining biodiversity and filtering environmental pollutants. The importance of mapping and monitoring their topographical changes is therefore paramount. This study focuses on the topographical variations at the Incheon River estuary wetland post-restoration, noting a lack of adequate prior measurements. Using a multi-temporal Sentinel-1 dataset from October 2014 to March 2023, we mapped long-term variations in water bodies and detected topographical change anomalies using a pixel-frequency approach. Our analysis, based on 196 Sentinel-1 acquisitions from an ascending orbit, revealed significant topography changes. Since 2020, employing the pixel-frequency technique, we observed area increases of +0.0195, 0.0016, 0.0075, and 0.0163 km² in water level sections at depths of 2-3 m, 1-2 m, 0-1 m, and less than 0 m, respectively. These findings underscore the effectiveness of the wetland restoration efforts in the area.

• Korean Journal of Environment and Ecology
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• v.36 no.6
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• pp.575-581
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• 2022

Brown rats (Rattus norvegicusBerkenhout, 1769) were eradicated from Sasudo Island (33°55'13.04" N, 126°38'19.98" E), an uninhabited island designated as Natural Monument No. 333 and the largest breeding site for the streaked shearwater (Calonectris leucomelasTemminck, 1835) in South Korea. Twelve eradication studies were conducted from November 2015 to February 2021. The survey was conducted using a line census method that entailed slow wandering throughout the island and identifying starting and returning points. Capture traps were installed around traces of Rattus norvegicus,such as excrement and identified holes. As a result, 2 to 6 individuals were captured at each instance, except for the last time, when no individuals were captured. It is hypothesized that brown rats arrived at Sasudo Island via vessels arriving at the island for leisure and fishing. After the damage to streaked shearwater caused by brown rats was confirmed in 2006, entry to Sasudo Island was strictly prohibited through security measures, and marine clean-up programs that began in 2013 and continuous capturing since 2015 have been successful in eradicating brown rats. To maintain and manage the condition in Sasudo Island, preservation and management measures, such as strict visitor control, are necessary to prevent the inflow of new brown rats in the future.