• Fisheries and Aquatic Sciences
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• v.13 no.3
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• pp.244-253
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• 2010

The quality of marine sediments from the industrialized coastal areas of Korea (Ulsan Bay, Masan Bay, and artificial Lake Shihwa) was investigated using a bacterial bioluminescence toxicity test. Sediment toxicity results were compared with the levels of chemical contamination (trace metals, organic wastewater markers, acid volatile sulfides, total organic carbon). Effective concentration 50% (EC50) of sediments ranged from 0.014 to 1.126 mg/mL, which is comparable to or lower than values in contaminated lakes, rivers, and marine sediments of other countries. Sediment reference index (SRI) ranged from 13 to 1044, based on the EC50 of the negative control sample. Mean average SRI values in Masan Bay and Lake Shihwa were approximately 8 and 9 times as high as that in Ulsan Bay, indicating higher sediment toxicity and greater contamination in the two former regions. Sediment toxicity were strongly associated with the concentrations of some chemicals, suggesting that this test may be useful for determining potential chemical contamination in sediments.

• Journal of Korean Port Research
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• v.14 no.4
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• pp.451-461
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• 2000

The design and maintenance of navigation channel and water facilities of an harbor which is located at the mouth of river or at the estuary area are difficult due to the complexity of estuarial water and sediment circulation. Effects of deepening navigable waterways, of changing coastline configurations, or of discharging dredged material to the open sea are necessary to be investigated and predicted in terms of water quality and possible physical changes to the coastal environment. A borad analysis of the transport mechanism in the estuary area was made in terms of sediment property, falling velocity, concentration and flow characteristics. In order to simulate the transport processes, a two-dimensional finite element model is developed, which includes erosion, transport and deposition mechanism of suspended sediments. Galerkin’s weighted residual method is used to solve the transient convection-diffusion equation. The fluid domain is subdivided into a series of triangular elements in which a quadratic approximation is made for suspended sediment concentration. Model could deal with a continuous aggregation by stipulating the settling velocity of the flocs in each element. The model provides suspended sediment concentration, bed shear stress, erosion versus deposition rate and bed profile at the given time step.

• Journal of the Korean Geotechnical Society
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• v.24 no.10
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• pp.113-120
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• 2008

It is difficult to acquire good-quality fill material for levee in field and it is the most important factor of levee construction technology to use the bed sediment for the safe and economic construction. So, it is necessary to evaluate geotechnical characteristics of bed sediment, design and construction method through field application tests. In this study geotechnical characteristics of Hyunpoong bed sediment (SP) in Daegu were analyzed, and laboratory/field compaction test for mixing granite weathered soil (SW) was performed. And field mixing method was suggested.

• Journal of The Korean Society of Agricultural Engineers
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• v.66 no.2
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• pp.53-62
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• 2024

This study assessed the efficiency of reducing soil erosion and suspended sediment through the restoration of alpine unauthorized and illegally cultivated fields, using the SWAT (Soil and Water Assessment Tool) model in the Mandae District. The results showed that in Scenario 5, which involved restoring unauthorized and illegal fields within forests, along rivers (banks), and in ditch areas were restored to their original land categories, achieved the highest efficiency in reducing average annual soil erosion and suspended sediment, with reductions of 8.1% and 4.5%, respectively. In particular, it was confirmed that the restoration of unauthorized and illegal fields within forested areas has a significant impact. This demonstrated that the restoration of unauthorized and illegal agricultural fields can substantially reduce the soil erosion and suspended sediment attributable to non-point source pollution. Our findings highlight the importance of managing these unauthorized and illegal agricultural activities in developing sustainable strategies within non-point source pollution management areas. This study is expected to provide important basic data to effectively establish water quality improvement strategies in the region of non-point source pollution management.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.3
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• pp.541-547
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• 2017

In Yongwon channel, its natural flow of seawater is blocked by the construction of Busan Newport including the container berth. The channel was transformed into a narrow and long one, where it is possible that ships are only allowed to pass through the north-side channel of Gyeonmado located at the point of river mouth to Songjeongcheon. So it is considered that the changes in the terrain characteristics of Yongwon channel is likely to alter the circulation of sea water, thereby changing its water quality. Contaminants are accumulated from the sediment release. In this study, before and after dredging the sediment release test was performed. As a result, after the sediment dredging is performed, the reduction rate was higher at the same point. The results show that the water quality can be improved by dredging. Each group (A~C) reduction rate of the evaluation of the reduction rate of 4.64% T-N, 18.00%, 18.59%, respectively. T-P rate of 24.75% reduction, 24.17%, 44.08%, respectively. COD reduction rate was 18.57%, 19.76%, 38.08%, respectively. These results can be used as basic data for controlling the contamination by dredging in Yongwon channel.

• Journal of Life Science
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• v.22 no.1
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• pp.80-86
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• 2012

This study was conducted to improve quality of takju where natural honey is used to control the ripening fermentation and the amount of sediment derived from takju mash. A koji was prepared using rice starch and Aspergillus awamori var. kawachii. Takju mash was prepared by alcohol fermentation with Saccharomyces cerevisiae and a 3-step addition of steamed rice. The clean part of the mash (CPM) was separated from the sediment at $5^{\circ}C$ and 5% (w/v) of natural honey was added and then ripened for 23 days at 5, 10, or $15^{\circ}C$. Temperature, pH, acidity, and total sugar content showed no significant differences, but a 0.2 percent reduction in alcohol content occurred during storage. However, CPM ripened with honey had a comparatively higher score on sensory evaluation than did immature CPM with added honey added. Takju with 8% alcohol content was prepared by mixing the water from the mixed CPM ripened with honey together with 100, 50, and 25% of the frozen sediment. Several quality characteristics of the takju were checked over 37 days of fermentation at $10^{\circ}C$. The pH was sustained between 4.1 and 4.3, and changes in the number of viable yeast cells, acidity, total sugar amounts, and alcohol content showed similar patterns but differences in scale. Smaller amounts of sediment affected the stability of the takju. Mixing the CPM ripened with natural honey at low temperature moderately reduced the amount of sediment in the mash and resulted in a highly flavorful takju with an extended shelf life.

• The Korean Journal of Food And Nutrition
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• v.29 no.1
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• pp.134-143
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• 2016

We evaluated the antioxidant properties of adzuki beans and the quality characteristics of sediment using various cultivation methods. There were significant differences in total polyphenol and flavonoid contents in beans grown using different methods of cultivation (p<0.05). Also, DPPH and ABTS radical-scavenging activities were significantly different depending on cultivation method (p<0.05). The sediment yield before drying of Chungju-pat, Hongeon, and Arari was 296.64~339.01, 271.36~282.24, and 268.21~292.32%, respectively, and the sediment yield after drying was 71.68~85.41, 77.90~85.19, and 74.15~78.65%, respectively. The L-value of Chungju-pat and Arari sediments revealed a significant difference given different cultivation methods (p<0.05), but Hongeon sediment did not show a significant difference. There was a significant difference in the a- and b-value of adzuki bean sediments cultivated using different methods (p<0.05). The particle size of Chungju-pat, Hongeon, and Arari sediments was 66.21~98.80, 61.62~97.07, and $82.96{\sim}106.71{\mu}m$, respectively, and all were significantly different depending on cultivation method (p<0.05). There were also significant differences in the water absorption index, water solubility index, and swelling power when different cultivation methods were used (p<0.05).

• Proceedings of KOSOMES biannual meeting
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• 2003.05a
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• pp.201-204
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• 2003

• Water for future
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• v.30 no.4
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• pp.28-34
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• 1997

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2004.11a
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• pp.44-44
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• 2004