• Journal of the Korean Geographical Society
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• v.42 no.1 s.118
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• pp.15-26
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• 2007

This study aims to estimate the similarities of lacustrine deposits of lava-dammed Yeoncheon paleo-lake by geochemical analysis such as XRF, ICP-AES, and 14C and OSL age datings in Chugaryeong Rift Valley of Central Korea. OSL age of the lacustrine coastal deposit(YC1) is estimated as 0.11-0.13 Ma. It indicates that paleo-deposits may have remained during at least 20,000 years from 0.13 Ma The origin analysis of deposits were carried out by comparison between lacustrine mud layers($YC1{\sim}2$) and various geomorphic materials of vicinity As a result, the similarity of the origin is highest between the paleo-coastal alluvial deposit of Chatan River(YC8), and surface clay deposit of Jeongok lava plateau(YC9) Next higher similarity is between paleo-lacustrine bottom deposit(YC2) and west valley-side mountain slope colluvial materials(YC5). Another high similarities are among present Chatan River channel sediment(YC7), acustrine coastal deposit(YC1) and east valley-side mountain slope colluvial materials(YC4).

• Journal of the Korean Geographical Society
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• v.40 no.6 s.111
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• pp.716-729
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• 2005

In the Yeongpyeong River, one of the branches of Hantan River, there 4 fluvial terraces are identified. During the Quaternary, lava flow from Hantan River had gone 4.5km into upstream Part of the Yeongpyeong River and damed its entrance, and resultantly its lower basin had become a lava-damed paleolake. This study deals with fluvial terrace surface classification, stratigraphic analysis, deposits analysis, and OSL age dating in from Gungpyeongri to Seongdongri in lower reach of Yeongpyeong River, in order to identify Seomorphological Process of the terrace landforms relating to duration of lava-damed paleolake. Terrace surface T4, named Baekeuiri Formation, has been located under Jeongok lava layer to indicate pre-lava river bed. Terrace surfaces T3 and T2 are supposed to be formed during paleolake time, based on $3{\~}4m$ thick sand deposits including pebble and cobble layers, and clay and silt layers intersected with sand ones in nearly horizontal bedding. Terrace T1 is estimated to be formed as post-lake fluvial terrace after dissection of lava dam, based on the more fresh phase of deposits and very low height from present riverbed. The results of the OSL age dating for the T3 deposit layers indicate approximately $33{\~}40ka$, and still lake phase at that time.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.207-211
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• 2011

하천공사의 매립 및 준설 시 뿐만 아니라 최근에는 호우 시에도 발생하는 고농도 오탁수의 유출 확산으로 인하여 주변 수역의 수산자원 및 자연환경에 심각한 영향을 미치고 있다. 특히 유사는 하천과 호소에 유입되어 탁도를 증가시켜 수자원의 이용가치를 저하시키며, 박테리아나 각종 미생물의 이동 매개체가 되고 있다. 또한 퇴적된 유사는 유량이 증가하면 다시 침식되어 부유상태가 되며 이때에 영양염류나 독성물질이 재용출 되기도 하는 등 하천의 물리 및 토양환경의 장 단기적인 변화를 유발하는 원인이 된다. 결국 유사는 다양한 방식으로 하천과 호소의 생태환경에 큰 변화를 초래한다. 부유토사의 발생 가능한 피해의 범위와 정도는 유역의 부유토사 발생율과 하천, 호소 퇴적물의 성분종류와 입도분포, 그리고 유속에 따라 결정된다. 따라서 탁수의 영향범위를 예측하고, 악영향이 예측될 경우에는 탁도를 저하시킬 수 있는 오탁물질의 저하기법을 적용하여 그 대책을 수립하여야 한다. 현재 정부가 역점을 두고 있는 4대강 살리기 사업 중 하나인 하천 준설 사업 시 발생되는 고농도 오탁수는 주변 수역의 수자원 및 자연환경에 심각한 영향을 미치므로 자연환경의 보존, 해양자원을 보호하기 위하여 오탁물질의 제어가 반드시 필요한 실정이다. 기존의 오탁 저감시설이나 방법의 경우 오탁물질의 확산을 제어하는데 한계가 있고 오탁물질의 종류와 관계없이 일률적으로 시공함으로서 오탁제어 효과가 의문 시 되고 있다. 이러한 문제점을 개선하기 위하여 오탁물질의 확산 범위를 줄이고 침강효율을 높이는 방법을 찾아 오탁확산 제어 효율을 개선할 필요가 있다. 본 연구에서는 오탁물질 제어 시 2차 응집물로 인한 오염이 발생하는 않는 천연광물 제올라이트를 이용한 실내실험을 통하여 고농도 탁수의 탁도 저감효율을 파악하여 고농도 탁수의 탁도 저감에 대한 제올라이트의 적용 가능성을 살펴보았다. 4대강 살리기 사업 중인 OO강 OO공구의 OO보 현장에서 하천 준설 시 발생하는 고농도 탁수를 이온을 첨가한 제올라이트를 이용하여 확산제어에 관한 효과를 검토한 결과 2,000NTU 정도의 고농도로 유하하는 탁수에 대하여 제올라이트 혼합 후 20분이 경과한 시점에 제거효율이 90%이상으로 제올라이트의 탁수저감 효과가 대단히 크다는 것을 알 수 있었다.

• Korean Journal of Ecology and Environment
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• v.41 no.3
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• pp.360-366
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• 2008

The spatial and temporal variations of the high turbid water by a single event of heavy rain (total 299.1 mm and daily maximum 99.4 mm) were studied in Andong Reservoir, which has hypolimnetic discharges. Turbid water entered into the reservoir, was isolated from the bottom at the midreservoir and then passed through the metalimnion as an interflow current in the lacustrine zone. Maximum turbidity was 290 NTU at 16 m depth of the midreservoir, but the initial turbidity showed about 10 NTU in the reservoir before the rainfall. Turbid water in the reservoir affected to increase the withdrawal turbidity from the 3rd day after the rainfall, the maximum turbidity was 129 NTU at 5th day after the rainfall. Turbid water that flew towards the downreservoir distributed within 5 m above the outlet gate of the intake tower, showing the maximum turbidity, and that was decreased in its thickness and concentration by discharging through the intake tower. It has taken 38 days until the turbidity in the withdrawal reduced to 30 NTU, and 87 days to reduce the turbidity to the way when it was before the rainfall, with the correlation coefficient of 0.96 and 0.97, respectively. Turbid water was withdrawn from the reservoir by entraining into the intake tower as a form of the interflow, and not be settled down to the bottom of the reservoir. Therefore, we assessed that the depth of the withdrawal was appropriately positioned in Andong Reservoir, so as to withdraw the turbid water effectively from the reservoir.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.431-431
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• 2016

J 호소는 1942년도에 충청남도 아산시 선장면에 설치된 농업용 저수지로서, 현재 COD, TN, TP 모두 등급외의 수질상태를 보이고 있다. J 호소 상류 유역은 축산농가가 다수 위치하고 있으며, 설치된 지 70년이 지난 노후화된 저수지로 고농도의 오염물질 유입뿐만 아니라 호소 바닥의 오염 퇴적물에 의한 내부 부하가 중요한 수질오염원이 되고 있다. 호소의 수질은 현재 COD 10.6~16.5 mg/L, Chl-a $75mg/m^3$ 이상으로 수질오염도가 매우 높으며, 특히 늦봄에서 초가을까지 외기온도 상승 및 저수율 저하와 함께 부영양화 증가, 녹조 대발생 등으로 호 내 물고기 대량 폐사 및 악취발생 등으로 민원이 다수 발생하고 있다. 이러한 현상의 직접적인 원인은 수중의 DO 농도 결핍이며, 따라서 수중의 DO 농도를 일정수준 이상으로 유지시켜 주는 것은 호소 수질관리를 위해 매우 필요하다고 판단된다. 본 연구에서는 공기 중의 산소를 호소 수체에 포기시켜 주는 마이크로버블 발생장치를 J 저수지에 설치하여 수체의 DO 농도 변화 등을 분석하였고, 본 연구결과는 농업용 호소의 수질개선을 위한 기술개발 및 계획수립의 기초자료로 활용하고자 하였다. 마이크로버블 포기장치는 수심이 약 4m 되는 저수지 제방 근처에 100m 간격으로 총 3지점에 설치하였다. 버블 발생기는 기액 2상류 선회형 마이크로 버블 발생장치로 3지점에 각 1set(1set에 3기로 구성)씩 구성하여 저수지 바닥 층에서 상부로 1m 떨어진 지점에 고정식으로 설치하였다. 총 공기흡입량은 380 LPM이며, 사용동력은 12.2kW를 사용하였다. 마이크로 버블 포기장치 설치 후 호 내 DO 농도 변화를 평가하기 위하여 호소 전체에 18개 지점을 선정하여 수심 50cm 간격으로 DO 농도를 측정하였다. 가동 전에는 DO 평균농도가 표층에서는 약 7.7mg/L로 나타났고, 수심에 따라 거의 수직적으로 감소하여 바닥층에서는 약 0.2mg/L로 거의 무산소 상태를 보이고 있었다. 마이크로 버블 가동 2주 후에는 수심 3m까지의 모든 수층에서 DO 농도가 약 6.0mg/L 이상을 보였고, 바닥층에서는 DO 약 3.4mg/의 농도를 나타내었다. 가동 3주 후에도 2주 후와 비슷한 수치를 보이고 있었으나 가동 4주가 지나면서부터는 호소 바닥층(수심 3.5m)에서도 DO 농도가 7.0mg/L 이상의 높은 농도를 유지하는 것으로 조사되었다. 호소 저층에서 호기성 상태의 지속적 유지는 퇴적 오염물질이 수층으로 용출되는 것을 예방할 수 있으므로 마이크로버블을 잘 활용하면 호소의 악취제거 및 수질개선에 많은 도움이 될 것으로 판단된다.

• The Journal of the Korean bone and joint tumor society
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• v.9 no.1
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• pp.84-92
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• 2003

Purpose: To report two cases of bone tumors other than osteoid osteoma in the proximal femur and treated with percutaneous high frequency radioablation method. Cases: We reviewed two cases with intracortical chondroma and enchondroma in the femoral head retrospectively. The patient with intracortical chondroma was a thirty one year old woman and had suffered right hip pain of 1 year duration. The lesion was located in the head of right femur and treated with CT guided percutaneous high frequency radioablation after needle biopsy under general anesthesia. The symptom was gone immediately after the procedure and was discharged postop. 1 day. 15 months has passed without symptom recurrence. Second case having enchondroma, was 56 year old woman complaining of gluteal area pain for 3 months. Radiologic evaluation showed osteolytic lesion with sclerotic rim on the inferior portion of the left femoral head. She received a same therapy with CT guided radiofrequency ablation following needle biopsy. She reported dramatic pain relief after the procedure and was discharged postop. 1 day. No symptom has occurred for 3 months until now. Conclusion: We present 2 cases of bone tumor occurred in the hip joint area other than osteoid osteoma which were treated with CT guided radiofrequency ablation.

• Korean Journal of Ecology and Environment
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• v.55 no.2
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• pp.156-166
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• 2022

Understanding the characteristics of reservoir water quality is fundamental in reservoir ecosystem management. The water quality of reservoirs is affected by various factors including hydro-morphology of reservoirs, land use/cover, and human activities in their catchments. In this study, we classified 83 major reservoirs in South Korea based on nine physicochemical factors (pH, dissolved oxygen, chemical oxygen demand, total suspended solid, total nitrogen, total phosphorus, total organic carbon, electric conductivity, and chlorophyll-a) measured for five years (2015~2019). Study reservoirs were classified into five main clusters through hierarchical cluster analysis. Each cluster reflected differences in the water quality of reservoirs as well as hydromorphological variables such as elevation, catchment area, full water level, and full storage. In particular, water quality condition was low at a low elevation with large reservoirs representing cluster I. In the comparison of eutrophication status in major reservoirs in South Korea using the Korean trophic state index, in some reservoirs including cluster IV composed of lagoons, the eutrophication was improved compared to 2004~2008. However, eutrophication status has been more impaired in most agricultural reservoirs in clusters I, III, and V than past. Therefore, more attention is needed to improve the water quality of these reservoirs.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.145-149
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• 2011

우리나라의 강우특성은 여름철인 6월~9월에 집중되며 대부분이 일시에 집중적으로 발생하여 하천을 통하여 호소 및 바다로 유입된다. 이러한 강우특성으로 여름철에 집중되는 강우로 인한 하천의 유량을 댐과 같은 수공시설물을 통해 저류시킴으로써 하류지역의 홍수피해를 예방하고 이용할 수 있는 물을 안정적으로 확보할 수 있도록 하고 있으나 대형 인공호의 유역에서는 인구 증가와 상업 및 공업화에 따른 토지이용이 변화함에 따라 오염물질의 유입이 증가하고 있는 추세이다. 댐이나 호소는 지표면에 고여 있는 수체를 말하며 물이 천천히 흐르거나 흐름이 전혀 없는 경우도 있다. 댐이나 호소에서는 장기간 수류의 지체현상이 발생하므로 발생하는 수체 및 수질의 문제가 하천과는 다르다고 할 수 있다(서동일 등, 2009). 호소의 물은 정체되어 있기 때문에 흐르는 물에 비해 자정능력이 부족하고 바닥에 퇴적된 유기물이 분해되어 수질에 나쁜 영향을 미치기 때문에 수질관리에 여러 가지 어려움이 따른다(박석순, 2009). 따라서 흐름방향 보다 수심방향으로의 특성이 강하게 작용하는 댐이나 호소에서는 3차원 수리 수질 모형의 적용이 타당하며 본 연구에서는 이를 위하여 EFDC를 적용하였다. 섬진강 유역의 경우 전체유역의 65.8%가 임야로 이루어진 산림유역으로 비교적 적은 양의 유역오염물질이 발생하지만 산불이나 벌채와 같은 산림의 손실은 홍수기 때 유역오염물질의 발생 및 유출을 증가시켜 주변수체의 수질을 악화시킬 우려가 있다. 이에 본 연구에서는 운암호 수질측정망 상류 유역면적인 $526.23km^2$에 대하여 토지변화 시나리오를 임야의 25%, 50%, 75%가 손실되어 나대지화 되었다고 가정하고, EFDC 모형을 이용하여 산림지역의 소실에 따른 토지피복 변화가 섬진강 댐 운암호의 수질에 미치는 영향 정도를 파악하였다.

• Journal of Environmental Impact Assessment
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• v.32 no.5
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• pp.291-304
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• 2023

Harmful algal blooms (HABs) have become an increasing concern in terms of human health risks as well as aesthetic impairment due to their toxicity. The reduction of water pollutants, especially nutrients from non-point sources in a reservoir watershed, is fundamental for HABs prevention. We investigated the pollutant removal efficiencies of a constructed wetland to evaluate its feasibility as a method for controlling non-point sources located in the Annaecheon stream within the Daecheong Reservoir watershed. The overall removal efficiencies of pollutants were as follows: BOD 14.3%, COD 17.9%, SS 50.0%, T-N 19.0%, and T-P 35.4%. These results indicate that constructed wetlands are effective in controlling pollutants from non-point sources. The seasonal variation in removal efficiency depended on the specific pollutants. The removal efficiencies of BOD, COD, and T-N were stable throughout the year, except during winter, which might have been influenced by lower microorganism activity. In contrast, T-P showed a consistent removal efficiency even during the winter season, suggesting that the wetland can reduce external phosphorus loading to the reservoir. Regarding the effects of pollutant loadings on removal efficiency, the effluent concentrations of all pollutants were significantly decreased compared to those in the influent in case of middle and high loadings. This demonstrates that constructed wetlands can handle high pollutant loads, including the initial runoff during rainfall, to prevent reservoir eutrophication. Despite the various strengths of wetland water purification, there are limitations as passive treatment. Therefore, more case studies should be conducted to suggest optimum operational conditions for constructed wetlands, taking into consideration reservoir-specific characteristics.

• Journal of Preventive Medicine and Public Health
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• v.26 no.2 s.42
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• pp.251-267
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• 1993

The relationship between lead related subject symptoms and lead exposure indices was studied in 435 male lead workers in thirteen lead using industries. 212 male office workers who were not exposed to lead occupationally were also studied as a control group. Fourteen lead related symptoms were selected. They were further subdivied into 4 sub-symptom groups such as 1) gastrointestinal, 2) neuromuscular and joint 3) constitutional, and 4) psychological symptoms. Symptom questionnaires were provided to the workers and filled up by themselves and reconfirmed by interviewer(doctor). The test used fer the evaluation of lead exposure were blood lead(PbB), zinc protoporphyrin in whole blood(ZPP), hemoglobin(Hb), hematocrit (Hct), delta-aminolevulinic acid in urine(DALA). The results obtained were as follows; 1. The higher prevalence rate in the sub-group of neuromuscular and joint symptoms was observed in occupationally lead exposed subjects than non-exposed subjects. Among the sub-groups, the most frequent symptom was 'numbness of finger, hands or feet', and the prevalence of the symptom of 'arthralgia', 'weakness of fingers, hands or feet' and 'myalgia' were higher in order. 2. While the symptom which showed the biggest difference of prevalence rate among the 14 symptoms between exposed and non-exposed subjects was 'numbness of fingers, hands or feet', the symptom which showed the highest prevalence rate was 'feeling tired generally' in exposed and non-exposed subjects, but no statistical difference of symptom prevalence were observed. 3. In total study population, PbB and ZPP had dose-response relationship with 4 symtoms of neuromuscular and joint symptoms ('numbness of finger, hands or feet', 'arthralgia', 'weakness of fingers, hands or feet' and 'myalgia') and one symptom of gastrointestinal group('intermittent pains in lower abdomen'). 4. In lead exposed workers, only neuromuscular and joint symptoms group showed dose-response relationship with PbB and ZPP, 5. In lead exposed workers, the prevalance rate of overall symptoms of lead workers with age below 39 years was higher than that of lead workers with age above 40. While neuromuscular and joint symptoms group had a dose-response relationship with PbB in former group, it had a dose-response relationship with ZPP in latter group. 6. Age adjusted odds ratios of symptoms of non-exposed with exposed and odds ratios of low exposed with high exposed workers showed the dose-response relationship of lead exposure with neuromuscular and joint symptoms group('numbness of fingers, hands or feet', 'arthralgia', 'weakness of fingers, hands or feet' and 'myalgia') and gastrointestinal symptoms group('intermittent pains in lower abdoman').