• Proceedings of KOSOMES biannual meeting
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• 2006.05a
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• pp.129-135
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• 2006

This study was performed to characterize the seasonal variation of water quality and sediment environment from May, 2004 to February, 2006 in 21 stations of Gwangyang bay. Gawngyang bay is located in the middle of south coast of Korea and semi-dosed with Yeosu peninsula, Gwangyang-city and Namhea-do. Water quality at the west coast of Myo-do were highly deteriorated than other stations. At summer season(July 2005), the concentration of the most analytical items were highly detected than other seasons and the lowest concentration was at the winter season(January 2005, February 2006). Especially, DIP and TP were highly detected around the coast of Yeosu industrial complex. N/P ratio were higher than 16 of Redfield ratio in the spring(May 2005) and winter(February 2006) at the surface layer. While at other seasons and most stations were lower than 16 of Redfield ratio. In the survey of sediment environment, ignition loss(IL), chemical oxygen demand(COD) and acid volatile sulfide(AVS) were in the range of $2.51\sim22.10%,\;2.65\sim48.41mg/g-dry\;and\;0.01\sim8.95mg/g-dry$, respectively. COD in surface sediment was highest at summer season AVS was highest at autumn. In sediment, the corelationship coefficients between COD and IL, COD and AVS were 0.65 and 0.44, respectively.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.1
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• pp.38-46
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• 2012

This study carried out current status, characteristics, and problems of coastal environment management on semi-enclosed Masan Bay in Korea and suggests cost-effective and eco-friendly water quality management policy. The pollutants from terrestrial sources into the Bay have apparently environmental pollution problems, such as eutrophication, red tide, and hypoxia. The carrying capacity of the Bay is estimated by hydrodynamic model and ecosystem model, material circulation including bivalve in ecosystem is analyzed by the growth model of bivalve. The resulting reduction in the input load was found to be 50~90%, which is unrealistic. When the efficiency of water quality improvement through bivalve farming was assessed based on the autochthonous COD, 30.7% of the total COD was allochthonous COD and 69.3% was autochthonous COD. The overall autochthonous COD reduction rate by bivalve aquaculture farm was found to be about 6.7%. This study indicate that bivalve farming is about 31% less expensive than advanced treatment facilities that remove both nitrogen and phosphorous.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.5
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• pp.414-422
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• 1984

This research was conducted to evaluate the effect of polluted Oncheon Stream on the marine organisms in the Suyeong Bay. Water quality and 96 hr acute toxicity to the sea urchin, Hemicentrotns pulcherrimus by recirculation bioassay were examined from Feb. 20 to Apr. 15, 1984. The 96 hr $50\%$ effective concentration($EC_{50}$) on the attachment of the podia of the sea urchin was observed to occur at test concentrations between 40.0 and $51.0\%$ (v/v), and safe concentrations may be assumed to be within 4.0 and $5.1\%$. These values indicate as follows : 1. Oncheon Stream was extremely polluted by oxygen-demanding wastes and synthetic organic compounds from sewage and industrial waste water. 2. Linear alkylbenzene sulfonate(LAS) which has not been yet included in water quality standard was discharged above the TLm. 3. Unknown toxicity may be synergy among complex substances. In consideration of the relationship between COD values of Oncheon Stream and dilution water, the effect of toxicity of Oncheon Stream water reached to the area of the Suyeong Bay where the COD value was found to be 12.2 ppm.

• The Journal of Engineering Geology
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• v.2 no.1
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• pp.70-91
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• 1992

Cheju and Oahu island are similar in geology, characterized by same types of volcanic activities during the late Tertiary to the early Quaternary. The occurrence of groundwater in both islands depend on two basic elements, permeability of volcanic rocks and precipitation. However, groundwater occurrence in Oahu is much more controlled by dike complex in the regional volcanic rocks. There are two different types of groundwater in both islands. One is perched groundwater standing at any high altitude, and the other is basal groundwater developed near the coastal area. The groundwater quality of Cheju island is good in general for drinking. But many wells near the eastern coastal area are salt intruded due to over pumping activities and the area of salt water intrusion has increased landward from the year of 1970. This feature of salt water contamination is similar at Pearl Harbour in Oahu island. In order to prevent this salt water contamination into fresh groundwater reservoir on Cheju island, it is urgently asked to make groundwater flow study along the coastal area on terms of groundwater potentials and their maximum ultimate exploration.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.3
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• pp.200-205
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• 2013

Pretreatment process is the critical step of RO (Reverse Osmosis) membrane desalination plant in order to prevent RO membrane fouling. The pretreatment as a key component of RO process must be designed to produce a constant and high quality RO feedwater which has low silt density index (SDI). This experiment was conducted to assess parameters affecting SDI value, such as pH, seawater turbidity, temperature, and coagulant dose. The experimental results indicated that the source seawater turbidity did cause little effects on SDI values of filtered water. The 0.45 um hydrophilic membrane was more appropriate than the hydrophobic membrane for measuring SDI. The SDI value was increased with decreasing pH under the condition of below pH 7.0. In addition, the water temperature significantly affected the SDI values, showing higher SDI value with lower water temperature.

• Journal of the Korea Organic Resources Recycling Association
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• v.21 no.1
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• pp.45-52
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• 2013

In this study, we had analyzed the ammonia removal efficiency in sea animal-culturing aquarium water using hypochlorous acid (HOCl) which is very reactive, no harm to human, and with no formation of toxic trihalomethane. The amount of hypochlorous acid for the removal of ammonia varied with the concentration of ammonia in samples, with 90% of removal efficiency for 30 minute reaction time in the sea water where the ratio of hypochloous acid to ammonia (w/w) is about 8.5 ~ 9.0, and 100% removal in the sample with the ratio of 9.8 ~ 10.1. The removal efficiency with the time was shown to be 90% within 10 minute in the ratio of 9.0 ~ 10.0. These results will effectively be used for the proper management and protection of sea animals in large aquarium through water clarification with hypochlorous acid by calculating the right amount and reaction time.

• Proceedings of KOSOMES biannual meeting
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• 2006.11a
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• pp.163-168
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• 2006

In order to develop the deep ocean water, we performed to study the characteristics of vertical distribution of dissolved trace metals(Cd, Co, Cu, Ni, Pb, Zn) from Apr. to Oct., 2005 in the East Sea. Total six sampling sites were selected in Gangwon-Do and Gyeongsanbuk-Do. Accuracy of the analytical procedures was assessed by the SRM(CASS-4) for dissolved metals in seawater. The mean recoveries of CASS-4 ranged from 89.4% for Co to 99.8% for Cd. In this study, the dissolved metal concentrations varied with space, time and element. The metal concentrations showed wide range in the surface. Cd, Ni and Zn showed a nutrient-type profile with surface depletion and enrichment at depth. However, Co, Cu and Pb were irregular in the vertical distribution. All metal concentrations studied in this study are lower than the criteria of Korean drinking water.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.21 no.2
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• pp.58-66
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• 2016

We have evaluated the ammonium data in seawater as a potential short-term index for marine environment through the following steps. 1. reviewing of chemical characteristics of ammonium in seawater, 2. comparative relationships of ammonium data with other water quality indices such as DO, COD, and nutrients from Typical Marine Environment(TME) and Special Marine Environment(SME). Ammonium data generally represent negative correlation with DO, while positive correlation with COD. In particular, under frequent cases of seawater conditions showing similar concentration of COD or DO, we have limited choice of explanation for such situation. However ODIN(ODIN/RDIN) or RDIN(RDIN/TDIN) ratio could provide advanced information to understand these seawater conditions. Based on these results, we suggest ammonium data as a potential short-period index for transilient marine environment, such as benthic flux of bottom sediment, hypoxia, and algal bloom. Under overcoming several handicaps, ammonium data could be an useful tool for better understand short transformation of marine environment.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.6
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• pp.899-905
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• 2022

Seawater management via Total Pollutant Load Management System (TPLMS) is crucial because it enables local governments to optimally allocate pollutant loads in order to best reduce pollutant load burden while supporting reasonable development. This study analyzed the feasibility of introducing a TPLMS on Gwangyang Bay, a specially managed sea area. We researched the inflow of pollutants and analyzed the present state of seawater quality in Gwangyang Bay and then discussed our findings and reviewed other specially managed sea area with the Gwangyang Bay Advisory Committee. We conclude that TPLMS on Gwangyang Bay is needed and suggest checking economic feasibility, ef iciency, and conducting continuous monitoring of seawater quality indicators such as chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP), heavy metals and polcyclic aromatic hydrocarbons (PAHs) prior to introducing a TPLMS in Gwangyang Bay.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.447-447
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• 2022

하굿둑 실증시험 및 개방 시 하굿둑으로부터 해안지역 대수층의 지하수 내 염분침투를 예방하고 지속가능한 지하수자원 이용과 관리를 위해서 담수(freshwater)와 염수(saltwater)의 경계면 변동 및 분포를 추적하기 위해 지화학적·물리적 접근 연구는 매우 중요하다. 해안 및 하굿둑 주변지역의 담·염수 경계면 특성에 관한 조사 및 분석은 직·간접적 관측방법으로 이뤄진다. 직접 관측방법에는 심도별 전기전도도(Electrical condutivity, EC) 측정 방법으로 1개 정밀센서(CTD-Diver)를 와이어에 연결하여 수동으로 측정하는 방식과 자동 관측센서(CTD-Diver)를 공내 여러 관심심도에 이격거리에 따른 관측센서를 여러 개 설치하여 특정 관심심도별 연속적인 상태를 파악하는 방법이다. 간접 관측방법에는 관심심도별 또는 특정 심도의 지하수 수질을 채취하여 지화학 분석하는 방법이 있다. 직·간접적 관측방법에는 관심심도별 구간의 이격거리와의 공백과 조사시기에 대수층의 해수침투를 파악할 수 있으나 연속적 관측과 예측은 매우 어렵다. 직접적 관측방법 중 1개 정밀센서와 와이어를 이용한 특정 시·공간에 대한 연직 프로파일링 관측은 가능하나, 연속적 관측과 예측 또한 매우 어렵다. 따라서 본 연구는 물리적 방법을 기반으로, 하굿둑 인근의 담수(freshwater)와 염수(saltwater)와의 경계면 분포특성에 관한 연구는 하굿둑 실증시험 시 지하수 내 염분침투에 따른 지하수 환경 등에 대한 전반적 특성 등을 분석하였다. 하구언 일대의 지하수 내 염분침투 및 지하수 오염관리를 위해 실증실험 등 인위적인 요소와 강우, 태풍, 가뭄 등 자연적인 요소에 의해 여러 형태의 분포특성을 보이는 담수와 염수의 분포 및 혼합대의 특성에 따른 담염수의 경계면 형태별 분석을 하는데 목적을 두었다. 해수침투의 예방과 지하수 오염 방지를 위해 심도별 자동 수질측정 장치를 개발하고, 이를 이용한 염지하수의 프로파일링 감시 시스템을 제안하였다.