• Journal of Korean Society on Water Environment
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• v.32 no.5
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• pp.465-474
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• 2016

Since Gyungan stream is included in the protected zone of the water supply source of the Metropolitan area in Korea, the water quality needs to be continuously managed. Therefore, a measure is required that can inhibit the flow of water pollutant into the water body and facilitate the ecological restoration of riparian vegetation. A field survey was conducted on the hydrological characteristics of the landscape elements established on the downstream catchment of the Gyungan stream, the result of which showed that the paddy field and urbanized area can be regarded as point pollution sources. The upland field can be regarded as a non-point pollution source. In order to improve the water quality in the Paldang lake, we first recommended creating a riparian vegetation belt. We also suggested introducing a treatment wetland and an artificial plant island to places in which the creation of a riparian vegetation belt is not ensured. We recommend creating a treatment wetland equipped with diverse functional groups. For creating the plant island, we recommend Zizania latifolia and Typha orientalis, which showed the highest productivity among aquatic plants. The former could be introduced around the outlet of a paddy field and the estuary of tributaries, while the latter could be introduced to a water body directly sourced from mountainous land.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.2
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• pp.135-140
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• 2017

The demand for aquatic products in the domestic and overseas is increased, so that the aquaculture industry can achieve high performance by controlling and standardizing the production even with a relatively small amount of resources compared with existing fisheries. However, traditional method has problems of low productivity such as natural disasters and ecosystem pollution, and it is necessary to develop a new culture system that can move to the optimal culture site. In order to find the optimal location, you need to collect and analyze the necessary data such as temperature and DO in real time. Data analysis was performed by using K-means clustering method based on machine learning, so that it was possible to decision when and where to move the farm by repeated unsupervised learning. The proposed research could solve the problems of low productivity such as natural disasters and ecosystem pollution if applied to regressive fish farmers.

• Journal of Environmental Science International
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• v.8 no.1
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• pp.115-123
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• 1999

Sewage has been almost treated by secondary treatment process. Secondary-treated effluent of sewage treatment plant caused the pollution of nearby beach. Nitrogen(N) and Phosphorus(P) in effluent water have caused many problems on estuary, such as red tide, eutrophication and aquatic toxicity. Therefore, the effective nitrogen and phosphorus removal from sewage treatment plants is necessary to prevent those pollution problems. However, little sewage treatment plant in Korea is effectively being operated for the removal of the nutrients. This study is analyzed for the effectiveness of cost when tertiary treatment process and Ocean Outfall are applied for the water quality of Suyong Bay After secondary treatment process, the effluent was discharged from the seabed in the depth of 32m of 4000m offshore. Pollutant concentration is decreased as much as the 180 times after the result of initial dilution, so that environmental protection requirement of Suyong Bay can satisfied. This Ocean Outfall process can save the 2.6~3.5 times as much as the cost of construction and operation for tertiary treatment process running over a 20 year.

• Journal of Ecology and Environment
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• v.43 no.4
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• pp.461-468
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• 2019

Background: This study aimed to identify NO₃^--N sources using the stable isotope δ¹⁵N in Chydorus sphaericus (OF Müller), to investigate hydrological characteristics and nutrient states in artificial wetlands near the Nakdong River. Chydorus sphaericus is dominant in wetlands where aquatic plants are abundant, occurring in high density, and is sensitive to wetland water pollution, making it suitable for identification of NO₃^--N sources. Results: NO₃^--N sources for each wetland were strongly dependent on hydrological characteristics. Wetlands with sewage or rainfall/groundwater as their main sources had high levels of NO₃^--N, whereas wetlands with surface water as their main input had comparatively lower levels. Since wetlands with sewage and rainfall/groundwater as their main water sources were mostly detention ponds, their inputs from tributaries or the main river stream were limited and nutrients such as NO₃^--N easily become concentrated. Changes in NO₃^--N levels at each wetland were closely associated with δ¹⁵N of C. sphaericus. Interestingly, regression analysis also showed positive correlation between δ¹⁵N of C. sphaericus and NO₃^--N level. Conclusions: We conclude that the nitrate stable isotope (δ¹⁵N) of C. sphaericus can be used to elucidate the hydrological characteristics of riverine wetlands. This information is important for maintenance and conservation of artificial wetlands at the Nakdong River.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.27 no.1
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• pp.1-16
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• 2024

The riparian area plays a crucial role in maintaining the balance between the aquatic and terrestrial ecosystems. The Korean government has recognized the importance of protecting riparian areas and has taken steps to purchase land and create ecobelt to reduce non-point source pollutants(NSPs) that can negatively impact water quality. However, selecting the catchment area and calculating the pollution load can be challenging due to the small area of the purchased land and the limitations of low-resolution DEMs. To address these challenges, this study proposes the use of unmanned aerial vehicles(UAVs) to create a high-resolution DEM and calculate the pollution load through land cover analysis. This approach can provide a more accurate representation of the land use status and help to identify areas that are contributing to NSPs. The quantitative comparison of the difference in water quality improvement ecosystem services according to the scenarios of additional catchment areas shows that even land purchased for the same amount of money may have different ecosystem service values, and this was quantitatively calculated. This can be used to prioritize future land acquisition. Overall, this study's approach could provide valuable insights into the effectiveness of ecobelt in reducing NSPs and inform future efforts to protect riparian areas in Korea and beyond.

• Korean Journal of Ecology and Environment
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• v.39 no.1 s.115
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• pp.62-72
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• 2006

Biological health in aquatic environments has been assessed by several approaches using various bio-taxa. Especially, fish has been identified as one of the best ecological indicators for an integrative health assessments in aquatic environments. In this preliminary study, the necropsy-based approach using the Health Assessment Index (Adams et al., 1993; HAI, Blazer, 2000), was employed for the assessments of aquatic environments influenced by effluent water from wastewater disposal plants (WDP) near a urban stream (i.e., Cap-Stream). For the impact analysis from the effluents, we developed 10 metric necropsy-based model including $M_l\;skin,\;M_2\;fin,\;M_3\;thymus,\;M_4\;spleen,\;M_5\;hindgut,\;M_6\;kidney,\;M_7\;liver.\;M_8\;eyes,\;M_9\;gill,\;and\;M_{10}$ pseudobranch. We set up duplicate controls (natural upstream water plus 5 fishes in each control tank) and duplicate treatments (effluent water from the WDP plus 5 fishes in each treatment tank) in the laboratory. Preliminary results showed that HAI values in the controls were zero, indicating an excellent condition by the criteria of HAI, while the HAI values in the treatments ranged between 40 and 150, indicating a poor condition. Also, various health conditions, based on the index of biological integrity (IBI), species richness, tolerance guilds, and trophic guilds supported the HAI approach. The HAI approach, not applied in Korea, not may be used as an surrogate fer ecological health assessment in lotic ecosystems.

• Fisheries and Aquatic Sciences
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• v.22 no.12
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• pp.30.1-30.11
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• 2019

Marine natural products isolated from the sponge Fascaplysinopsis cf reticulata, in French Polynesia, were investigated as an alternative to antibiotics to control pathogens in aquaculture. The overuse of antibiotics in aquaculture is largely considered to be an environmental pollution, because it supports the transfer of antibiotic resistance genes within the aquatic environment. One environmentally friendly alternative to antibiotics is the use of quorum sensing inhibitors (QSIs). Quorum sensing (QS) is a regulatory mechanism in bacteria which control virulence factors through the secretion of autoinducers (AIs), such as acyl-homoserine lactone (AHL) in gram-negative bacteria. Vibrio harveyi QS is controlled through three parallel pathways: HAI-1, AI-2, and CAI-1. Bioassay-guided purification of F. cf reticulata extract was conducted on two bacterial species, i.e., Tenacibaculum maritimum and V. harveyi for antibiotic and QS inhibition bioactivities. Toxicity bioassay of fractions was also evaluated on the freshwater fish Poecilia reticulata and the marine fish Acanthurus triostegus. Cyclohexanic and dichloromethane fractions of F. cf reticulata exhibited QS inhibition on V. harveyi and antibiotic bioactivities on V. harveyi and T. maritimum, respectively. Palauolide (1) and fascaplysin (2) were purified as major molecules from the cyclohexanic and dichloromethane fractions, respectively. Palauolide inhibited QS of V. harveyi through HAI-1 QS pathway at 50 ㎍ ml^-1 (26 μM), while fascaplysin affected the bacterial growth of V. harveyi (50 ㎍ ml^-1) and T. maritimum (0.25 ㎍). The toxicity of fascaplysin-enriched fraction (FEF) was evaluated and exhibited a toxic effect against fish at 50 ㎍ ml^-1. This study demonstrated for the first time the QSI potential of palauolide (1). Future research may assess the toxicity of both the cyclohexanic fraction of the sponge and palauolide (1) on fish, to confirm their potential as alternative to antibiotics in fish farming.

• Korean Journal of Environmental Biology
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• v.27 no.4
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• pp.391-396
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• 2009

The biological effects of carcinogenic polycyclic aromatic hydrocarbons (cPAHs) including benzo[a]pyrene (BaP), dibenzo[a,h]anthracene (DBA), benzo[a]anthracene (BaA), benzo[b] fluoranthene (BbF), benzo[k]fluoranthene (BkF), and indeno[1,2,3-c, d]pyrene (InP) on transcriptomic changes were determined in the liver of Oryzias latipes. Differentially expressed genes (DEGs) by binary exposure to cPAHs (BaP+BaA, BaP+BbF, BaP+BkF, BaP+DbA, BaP+InP) were screened by annealing control primers-based polymerase chain reaction followed by sequence analysis and BLAST searching. The results showed that four DEGs were commonly expressed by cPAHs and they were identified as ribosomal protein S4, coagulation factor II, elongation factor 1 beta, and a predicted protein similar to human immunodeficiency virus type I enhancer binding protein 3. This finding suggests that binary exposure to cPAHs interferes protein synthesis required for fundamental liver functions in fish.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.07a
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• pp.177-178
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• 2015

Sediments play a major role in determining pollution pattern in aquatic systems and reflecting the pollutant deposition. In the present study analysis the depth effect of organic pollutants and heavy metals using slow release biostimulant ball (BSB) in coastal sediment. BSB size fixed at 3cm, depth varied from 0cm to 10cm depth and 1 and 3 month interval period was carried out for the study. The organic pollutants of chemical oxygen demand, total solids and volatile solids were significantly changed at the surface sediment (0cm)in 1 month and 3 month interval time using BSB. In contrast, sediment depth increase upto 10cm the reduction percentage decrease like to control. Vertical distribution of heavy metals are not consistent from the surface layer toward the bottom layers. Heavy metals fractions were significantly changes, the exchangeable fraction was reduced and other organic and residual fractions were stabilized percentage are increased. This finding concluded BSB is effective for reduce organic pollutants, heavy metals stabilization from the contaminated sediment.

• Journal of Power System Engineering
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• v.19 no.2
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• pp.84-89
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• 2015

The occurrence of algae caused by eutrophication of fresh water is a pollution source to destroy the aquatic environment. When the high voltage electric field is applied in the water, When a high voltage is applied to the electric field in the water, the algae can be broken the balance of cell membranes, and is dead. In this paper, we develop a water quality improvement system for generating an electric field having a higher energy than the zeta potential when a high voltage is applied to 4,000V. To ensure the mobility of the water quality improvement system, we designed the PV generation system using the optimal size technique that is based on the model of power lack ratio. By evaluating the output characteristics of the water quality improvement system, power generation characteristics of the PV generation system, and battery charging characteristics, we can show that the proposed system can be applicable to the water quality improvement system inhibiting the growth rate of the algae in the fresh water.