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Institution

Korean Ocean Research and Development Institute

FacilityBusan, South Korea
About: Korean Ocean Research and Development Institute is a facility organization based out in Busan, South Korea. It is known for research contribution in the topics: Sea surface temperature & Bay. The organization has 1770 authors who have published 3032 publications receiving 50142 citations.


Papers
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Journal ArticleDOI
TL;DR: In this paper, the authors investigated the influence of precipitation and river stage on the sustainable performance of foundations of various urban buildings and infrastructures, as GWL causes changes in the stress state within soil.
Abstract: The sustainable performance of foundations of various urban buildings and infrastructures is strongly affected by groundwater level (GWL), as GWL causes changes in the stress state within soil. In the present study, the components affecting GWL were investigated, focusing on the effects of precipitation and river stage. These components were analyzed using a six-year database established for hydrological and groundwater monitoring data. Five study regions for which daily measured precipitation, river stage, and GWL data were available were compared. Different periods of precipitation, geographical characteristics, and local surface conditions were considered in the analysis. The results indicated that key influence components on GWL are different depending on the hydrological, geological, and geographical characteristics of the target regions. River stage had the strongest influence on GWL in urban areas near large rivers with a high ratio of paved surface. In rural areas, where the paved surface area ratio and soil permeability were low, the moving average showed a closer correlation to GWL than river stage. A moving average-based method to predict GWL variation with time was proposed for regions with a low ratio of paved surface area and low permeability soils.

1,051 citations

Journal ArticleDOI
TL;DR: In vitro tests revealed that antioxidant-related enzymes and MAPK signaling pathways were significantly activated in response to microplastic exposure in a size-dependent manner, suggesting that 6-μm microbeads are more effectively egested from B. koreanus than 0.05- or 0.5- μm microBeads.
Abstract: In this study, we evaluated accumulation and adverse effects of ingestion of microplastics in the monogonont rotifer (Brachionus koreanus). The dependence of microplastic toxicity on particle size was investigated by measuring several in vivo end points and studying the ingestion and egestion using 0.05-, 0.5-, and 6-μm nonfunctionalized polystyrene microbeads. To identify the defense mechanisms activated in response to microplastic exposure, the activities of several antioxidant-related enzymes and the phosphorylation status of mitogen-activated protein kinases (MAPKs) were determined. Exposure to polystyrene microbeads of all sizes led to significant size-dependent effects, including reduced growth rate, reduced fecundity, decreased lifespan and longer reproduction time. Rotifers exposed to 6-μm fluorescently labeled microbeads exhibited almost no fluorescence after 24 h, while rotifers exposed to 0.05- and 0.5-μm fluorescently labeled microbeads displayed fluorescence until 48 h, suggesting that 6-μm microbeads are more effectively egested from B. koreanus than 0.05- or 0.5-μm microbeads. This observation provides a potential explanation for our findings that microbead toxicity was size-dependent and smaller microbeads were more toxic. In vitro tests revealed that antioxidant-related enzymes and MAPK signaling pathways were significantly activated in response to microplastic exposure in a size-dependent manner.

782 citations

Journal ArticleDOI
TL;DR: The number of fragmented polymer particles produced by ultraviolet exposure and mechanical abrasion increased with decreasing size in all polymer types, and the size-normalized abundance of the fragmented PE, PP, and EPS particles according to particle size after UV exposure and MA was predictable.
Abstract: It is important to understand the fragmentation processes and mechanisms of plastic litter to predict microplastic production in the marine environment. In this study, accelerated weathering experiments were performed in the laboratory, with ultraviolet (UV) exposure for up to 12 months followed by mechanical abrasion (MA) with sand for 2 months. Fragmentation of low-density polyethylene (PE), polypropylene (PP), and expanded polystyrene (EPS) was evaluated under conditions that simulated a beach environment. PE and PP were minimally fragmented by MA without photooxidation by UV (8.7 ± 2.5 and 10.7 ± 0.7 particles/pellet, respectively). The rate of fragmentation by UV exposure duration increased more for PP than PE. A 12-month UV exposure and 2-month MA of PP and PE produced 6084 ± 1061 and 20 ± 8.3 particles/pellet, respectively. EPS pellets were susceptible to MA alone (4220 ± 33 particles/pellet), while the combination of 6 months of UV exposure followed by 2 months of MA produced 12,152 ± 3276 particles/pellet. The number of fragmented polymer particles produced by UV exposure and mechanical abrasion increased with decreasing size in all polymer types. The size-normalized abundance of the fragmented PE, PP, and EPS particles according to particle size after UV exposure and MA was predictable. Up to 76.5% of the initial EPS volume was unaccounted for in the final volume of pellet produced particle fragments, indicating that a large proportion of the particles had fragmented into undetectable submicron particles.

768 citations

Journal ArticleDOI
TL;DR: The results suggest that microplastics such as micro- or nanosized PS beads may have negative impacts on marine copepods.
Abstract: We investigated the effects of three sizes of polystyrene (PS) microbeads (0.05, 0.5, and 6-μm diameter) on the survival, development, and fecundity of the copepod Tigriopus japonicus using acute and chronic toxicity tests. T. japonicus ingested and egested all three sizes of PS beads used and exhibited no selective feeding when phytoplankton were added. The copepods (nauplius and adult females) survived all sizes of PS beads and the various concentrations tested in the acute toxicity test for 96 h. In the two-generation chronic toxicity test, 0.05-μm PS beads at a concentration greater than 12.5 μg/mL caused the mortality of nauplii and copepodites in the F0 generation and even triggered mortality at a concentration of 1.25 μg/mL in the next generation. In the 0.5-μm PS bead treatment, despite there being no significant effect on the F0 generation, the highest concentration (25 μg/mL) induced a significant decrease in survival compared with the control population in the F1 generation. The 6-μm PS beads d...

698 citations

Journal ArticleDOI
TL;DR: In this article, the authors conducted a literature survey to review the current identification methods for microplastics and compared the advantages and limitations of each identification method to indicate the best methods for the microplastic analysis.
Abstract: Microplastics have become a major global environmental issue in recent decades due to their ubiquity in the oceans, bioavailability and ability to carry toxic chemicals. Analysis of microplastics in environmental and experimental samples has become increasingly common. We conducted a literature survey to review the current identification methods for microplastics. The advantages and limitations of each identification method were compared to indicate the best methods for microplastic analysis. Identification of microplastics is based on the physical and chemical characterisation of isolated particles in mixtures of inorganic and organic remnant particles after the extraction and clean-up steps. In addition, novel methods which may possibly be applied to microplastic identification were suggested. Microscopic identification by itself has a high risk of producing both false positive and false negative results in analyses of small microplastics. At present, combinations of physical (e.g., microscopy) and chemical (e.g., spectroscopy) analyses are widely used. However, there is a need to improve and develop new methods to reduce the identification time and effort and to detect sub-micron plastics in environmental samples.

563 citations


Authors

Showing all 1787 results

NameH-indexPapersCitations
Ian H. Campbell7520418767
Ravi Shankar6667219326
Claude F. Boutron5717611220
Carlo Barbante5634713942
Won Joon Shim5621110099
Jong-Seong Kug4924811337
Dong-Gyu Jo471677599
Jong Seok Lee4639911661
Jong Seong Khim432356783
Sang Hee Hong41985804
Paolo Cescon401314161
Jung-Hyun Lee382155045
Narayanan Kannan381406116
Nan Li381835184
Sungmin Hong35994130
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202328
202222
2021223
2020260
2019286
2018259