• Title, Summary, Keyword: Marine sediment

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Electrokinetic Extraction of Metals from Marine Sediment (중금속으로 오염된 해양퇴적토의 전기동력학적 정화)

  • Kim, Kyung-Jo;Yoo, Jong-Chan;Yang, Jung-Seok;Baek, Kitae
    • Korean Chemical Engineering Research
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    • v.51 no.6
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    • pp.733-738
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    • 2013
  • Sediment contains a high fraction of organic matter, high buffering capacity, and a large portion of fine grained particles such as silt and clay, which are major barriers to remove heavy metals from sediments. In this study, a lab-scale electrokinetic (EK) technique was applied to remove heavy metals effectively from marine sediment at a constant voltage gradient of 2 V/cm. A concentration of 0.1 M of ethylenediaminetetraacetic acid (EDTA), citric acid (CA), $HNO_3$, and HCl were circulated in the cathode, and tap water was circulated in the anode. CA extracted 92.4% of Ni, 96.1% of Cu, 97.1% of Zn, and 88.1% of Pb from marine sediment. A higher voltage gradient enhanced the transport of citrate and EDTA into the sediment and, therefore, increased metal extraction from the marine sediment through a complexation reaction between metals and the chelates. Based on these results, the electrokinetic process using a high voltage gradient with EDTA and CA might be useful to extract heavy metals from marine sediment.

Database of Navigational Environment Parameters (Water Depth, Sediment Type and Marine Managed Areas) to Support Ships in an Emergency

  • Kim, Tae-Ho;Yang, Chan-Su
    • Journal of Navigation and Port Research
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    • v.43 no.5
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    • pp.302-309
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    • 2019
  • This study introduces the navigational environment database(DB) compiling water depth, sediment type and marine managed areas (MMAs) in coastal waters of South Korea. The water depth and sediment data were constructed by combining their sparse points of electronic navigation chart and survey data with high spatial resolution using the inverse distance weighting and natural neighbor interpolation method included in ArcGIS. The MMAs were integrated based on all shapefiles provided by several government agencies using ArcGIS because the areas should be used in an emergency case of ship. To test the validity of the constructed DB, we conducted a test application for grounding and anchoring zones using a ship accident case. The result revealed each area of possible grounding candidates and anchorages is calculated and displayed properly, excluding obstacle places.

Prediction of Cohesive Sediment Transport and Flow Resistance Around Artificial Structures of the Beolgyo Stream Estuary

  • Cho, Young-Jun;Hwang, Sung-Su;Park, Il-Heum;Choi, Yo-Han;Lee, Sang-Ho;Lee, Yeon-Gyu;Kim, Jong-Gyu;Shin, Hyun-Chool
    • Fisheries and aquatic sciences
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    • v.13 no.2
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    • pp.167-181
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    • 2010
  • To predict changes in the marine environment of the Beolgyo Stream Estuary in Jeonnam Province, South Korea, where cohesive tidal flats cover a broad area and a large bridge is under construction, this study conducted numerical simulations involving tidal flow and cohesive sediment transport. A wetting and drying (WAD) technique for tidal flats from the Princeton Ocean Model (POM) was applied to a large-scale-grid hydrodynamic module capable of evaluating the flow resistance of structures. Derivation of the eddy viscosity coefficient for wakes created by structures was accomplished through the explicit use of shear velocity and Chezy's average velocity. Furthermore, various field observations, including of tide, tidal flow, suspended sediment concentrations, bottom sediments, and water depth, were performed to verify the model and obtain input data for it. In particular, geologic parameters related to the evaluation of settling velocity and critical shear stresses for erosion and deposition were observed, and numerical tests for the representation of suspended sediment concentrations were performed to determine proper values for the empirical coefficients in the sediment transport module. According to the simulation results, the velocity variation was particularly prominent around the piers in the tidal channel. Erosion occurred mainly along the tidal channels near the piers, where bridge structures reduced the flow cross section, creating strong flow. In contrast, in the rear area of the structure, where the flow was relatively weak due to the formation of eddies, deposition and moderated erosion were predicted. In estuaries and coastal waters, changes in the flow environment caused by artificial structures can produce changes in the sedimentary environment, which in turn can affect the local marine ecosystem. The numerical model proposed in this study will enable systematic prediction of changes to flow and sedimentary environments caused by the construction of artificial structures.

A Research on Diagnosis of Institutional Problem and Improvement Plan for Management in Coastal Dredged Sediment - Case Study of Masan Bay - (연안준설토 관리의 제도적 문제점 진단 및 개선방안 연구 - 마산만 사례를 중심으로 -)

  • Yi, Yongmin;Oh, Hyuntaik;Lee, Dae In;Kim, Gui Young;Jeon, Kyeong Am;Kim, Hye Jin
    • Journal of Environmental Impact Assessment
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    • v.24 no.5
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    • pp.444-455
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    • 2015
  • In relation to the utilization and disposal of dredged sediment caused by coastal dredging project, we diagnosed the status of legal standard and system, and proposed the improvement plan. Dredging costal sediment distinguished the usage and the disposal by the Standard for the Beneficial Usage of Dredged Sediment. The site where disposal has been completed could be used as a site for developmental project. In case of the usage of dredged sediment for reclamation, we found that the adaptation of the Standard for Beneficial Usage of Dredged Sediment is appropriate for reclamation considering the characteristic of soil, the differences of variables, and the distinction of standard analysis methods. The current the Standard for Beneficial Usage of Dredged Sediment requires the improvement with the usage of dredging coastal sediment in the following. First, the Standard needs to include the standard of the discrimination for reclamation. Second, the current Standard is necessary to be divided by two levels, it needs to be mitigated considering human health risk. Third, it is necessary to consider both the marine environmental impact assessment and mitigation plan near coastal dredging area.

Stabilization of Heavy Metals in Contaminated Marine Sediment using Bentonite (벤토나이트에 의한 해양오염퇴적물 내 중금속 안정화 특성)

  • Shin, Woo-Seok;Na, Kyu-Ri;Kim, Young-Kee
    • Journal of Navigation and Port Research
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    • v.38 no.6
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    • pp.655-661
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    • 2014
  • In this study, stabilization treatment of heavy metals such as Ni, Cu, Pb, and Zn in contaminated marine sediment was achieved using bentonite. Stabilization experiment was accomplished by wet-curing with bentonite for 150 days. From the sequential extraction results of heavy metals, it was observed that the easily extractable fraction (exchangeable, carbonate, and oxides forms) of Ni, Cu, Pb, and Zn in a treated sediment decreased to 8.5%, 5.6%, 19.2%, and 28.2%, respectively, compared with untreated sediment. Moreover, the TCLP(Toxicity Characteristic Leaching Procedure) results evaluating efficiency of extraction reduction of heavy metals showed that extraction of heavy metals reduced drastically to 95.7%, 96.8%, 99.2%, 85.9% for Ni, Cu, Pb, and Zn by stabilization when compared to untreated sediment. From these results, we can confirm that bentonite as a capping material exhibits good stabilization of heavy metals in contaminated marine sediment.

Studies on Toxicological Evaluation of Freshwater Sediment using a PLHC-1 Cell Comet Assay (PLHC-1세포주의 Comet assay를 이용한 하천 퇴적토의 생태독성평가)

  • Bak, Jeong-Ah;Hwang, In-Young;Baek, Seung-Hong;Kim, Young-Sug
    • Korean Journal of Environmental Biology
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    • v.29 no.1
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    • pp.23-30
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    • 2011
  • In this study, the Comet assay (evaluation of DNA damage) used the fish hepatocellular carinoma cell, PLHC-1, was tried to the sediment extract obtained from freshwater to understand its applicability as a tool for monitoring sediment toxicity. In parallel, induced EROD (7-ethoxyresorufin- O-deethylase) activity and DNA damage (TEM values) in PLHC-1 cells were measured for establishing the tandem endpoints of the PLHC-1cell test to test the ecotoxicity of sediment. Among several study sites in a small river passed through downtown and industrial park area, one of them, site B, showed a higher level of EROD activity and DNA damage than other sites. It indicates that a tandem endpoints of PLHC-1 cells could be useful tools for assessing the toxicity of sediment. The sensitivity of Comet assay with PLHC-1 cells was a little higher than that with a blood cell of frog tadpoles to the solvent extract of sediment. According to the results, a PLHC-1 cell-Comet assay could be used as a useful tool for evaluating ecotoxicity of the freshwater sediment. In addition, more detailed studies are needed to the contaminated site.

Microbial community structure analysis from Jeju marine sediment (제주도 인근 해양퇴적물 내의 미생물 군집 구조분석)

  • Koh, Hyeon Woo;Rani, Sundas;Hwang, Han-Bit;Park, Soo-Je
    • Korean Journal of Microbiology
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    • v.52 no.3
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    • pp.375-379
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    • 2016
  • In this study, the structure and diversity of bacterial community were investigated in the surface and subsurface marine sediments using a NGS method (i.e. illumina sequencing technology). The bacterial community in the surface was distinct from that in the subsurface of marine sediment; with the exception of the phylum Proteobacteria, the relative abundance of Bacteroides phylum were higher in the surface than subsurface, whereas the sequences affiliated to the phyla Chloroflexi and Acidobacteria were relatively more copious in the subsurface than surface sediment. Moreover, interestingly, we observed that the phyla Nitrospinae and Nitrospirae contribute to nitrogen cycle in the marine sediment. This study may present the possibility for the presence of novel microorganisms as unexplored sources and provide basic information on the microbial community structure.

An Experimental Study on Properties of Seabed Unconsolidated Sediment for Wind Power System Construction (해상풍력발전단지 건설 시 해양미고결지반 물성 파악을 위한 실험 연구)

  • Yoo, Hyun-Jong;Lim, Jong-Se;Shin, Sung-Ryul;Jang, Won-Yil;Yoon, Ji-Ho
    • Journal of the Korean Society of Marine Engineering
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    • v.32 no.2
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    • pp.365-373
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    • 2008
  • When the wind power system is planned to construct, it is important to understand the physical, chemical and mechanical properties of sediment. Especially, If it is the seabed unconsolidated sediment, we need to experiment on sediment through seabed unconsolidated sediment test and sediment survey. Because the sediment's properties are different as its formation, accumulation and load, unconsolidated sediment is difficult to be expected to its behavior. So we can estimate suitability for mechanical material and decrease the uncertainty through seabed unconsolidated sediment test. Seabed unconsolidated sediment test can be experimented in laboratory or in-situ as purpose, in-situ condition, economic problem. In this study, we sampled the seabed unconsolidated sediment at offshore around Korea Maritime University and measured properties of sediment through the laboratory test, showed the effect on physical properties of seabed unconsolidated sediment when the wind power system is planned to construction.

The Sediment-Water Interface Increment due to the Complex Burrows of Macrofauna in a Tidal Flat

  • Koo, Bon-Joo;Kwon, Kae-Kyoung;Hyun, Jung-Ho
    • Ocean Science Journal
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    • v.40 no.4
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    • pp.221-227
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    • 2005
  • The architecture of macrofaunal burrows and the total area of the sediment-water interface created by biogenic structure were investigated in the Donggeomdo tidal flat on the west coast of Korea. Resin casting methods were applied to recover burrows of four dominant species, Macrophthalmus japonicus, Cleistostoma dilatatum, Perinereis aibuhitensis, and Periserrula leucophryna, and whole burrows within the casting area at three sites in different tidal levels. P. leucophryna excavated the largest burrow in terms of a surface area among them. In the case of whole burrow casting, the space occupied by the biogenic structure was extended into deeper and expanded more greatly at the higher tidal level. In the uppermost flat, the burrow wall surface area within sediment was more extensive than the sediment surface area. Increased oxygen supply through the extended interface could enhance the degradation rates of organic carbon and also change the pathways of degradation. Quantifying the relationship between the extended interface and mineralization rate and pathway requires more extensive study.

Application of Red Mud and Oyster Shell for the Stabilization of Heavy Metals (Pb, Zn and Cu) in Marine Contaminated Sediment (적니와 굴패각을 이용한 해양오염퇴적물 내 중금속(Pb, Zn and Cu) 안정화 처리)

  • Shin, Woo-Seok;Kang, Ku;Park, Seong-Jik;Um, Byung-Hwan;Kim, Young-Kee
    • Journal of Korean Society of Environmental Engineers
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    • v.34 no.11
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    • pp.751-756
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    • 2012
  • In this study, a heavy-metal stabilization treatment using stabilizing agents derived from waste resources was utilized on Incheon North Port range sediment contaminated with Pb, Zn, and Cu. Both calcined red mud (5%, 10%, and 15% w/w) and oyster shell (5%, 10%, and 15% w/w) were applied for a wet-curing duration of 15 days. From the sequential extraction results, the oxide and organic fraction of heavy metals (Pb, Zn, and Cu) were observed strongly in the contaminated sediment. However, the fraction of heavy metal in the stabilized sediment was higher than the organic and residual fraction, in comparison to the contaminated sediment. Moreover, the leaching of heavy metals was reduced in the stabilized sediment, compared with the contaminated sediment. From these results, red mud and oyster shell were shown to be potential stabilizers of heavy metals in contaminated sediment.