• Journal of Ecology and Environment
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• 제40권1호
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• pp.24-33
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• 2016

Background: Previous numerous studies on watershed scale demonstrated that the constructions of upper dams may influence the below dams due to modifications of flow regime and nutrient inputs. Little is known about how the dam constructions influence the downstream lakes or reservoirs in the regional scale. This study demonstrates how the construction of upper dam (i.e., Yongdam Dam) influences nutrient regime, trophic relations, and empirical models in Daechung Reservoir (DR). Yongdam Dam was constructed at the upstream region of DR in year 2000. Results: The analysis of hydrological variables showed that inflow and discharge in the DR were largely reduced after the year 2000. The construction of upper dam construction also resulted in increases of water temperature, pH and conductivity (as an indicator of ionic content) in the DR. Empirical models of TP-CHL and N:P ratio-CHL suggested that stronger responses of CHL to the phosphorus were evident after the upper dam construction, indicating that algal production at a unit phosphorus increased after the upper dam construction. Mann-Kendall tests on the relations of N:P ratios to TN showed weak or no relations ($t_{au}=-0.143$, z = -0.371, p = 0.7105) before the dam construction, while the relation of N:P ratios to TP showed strong in the periods of before- ($t_{au}=-0714$, z = -2.351, p = 0.0187) and after the construction ($t_{au}=-0.868$, z = -4.270, p = 0.0000). This outcome indicates that TP is key determinant on N:P ratios in the reservoir. Scatter Plots on Trophic State Index Deviations (TSIDs) of "TSI(SD) - TSI(CHL)" against "TSI(TP) - TSI(CHL)" showed that the dominance of clay turbidity or light limitation was evident before the upper dam construction [TSI(TP) - TSI(CHL) > 0 and TSI(SD) - TSI(CHL) > 0] and phosphorus limitation became stronger after the dam construction [(TSI(TP) - TSI(CHL) < 0 and TSI(SD) - TSI(CHL) > 0]. Conclusions: Overall, our analysis suggests that the upper dam construction modified the response of trophic components (phytoplankton) to the nutrients or nutrient ratios through the alteration of flow regime, resulting in modifications of ecological functions and trophic relations in the low trophic levels.

• 한국해안해양공학회지
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• 제18권3호
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• pp.198-210
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• 2006

본 연구에서 이용한 3차원 유동모델인 POM(Princeton Ocean Model)은 저층수의 거동예측에 유리한 ${\sigma}$ 좌표계를 채용하고 있는 모델로서 범용성이 높고, 해양유동모델로서 개발되었지만 최근에는 연안역에서의 적용 예(박경 등, 1998)도 증가하고 있다. 기존의 POM은 ${\sigma}$좌표계 모델의 좌표변환에 기인한 수치오차에 대한 보정을 실시하지 않은 모델로서, 이러한 수치오차를 축소시키는 것은 저층부근의 유속의 정도향상에 매우 중요하지만 오차의 축소를 시도하지 않고 그대로 적용하고 있는 실정이다. 따라서, 본 연구에서는 $Sl{\Phi}rdal$(1997)이 제안한 방법을 이용하여 오차보정을 통한 3차원 유동모델인 POM의 정도향상을 실시하였다. 구축된 모델을 이용하여 우리나라의 대표적인 기수호중 하나인 영랑호에 적용하여 저층수의 거동을 파악하고 빈산소수괴를 포함한 저층수의 거동 및 형성기구를 명확히 할 수 있는 자료로서 활용하고자 하였다. 적용결과, 기존 POM모델과 비교하여 개량형 POM모델을 이용하였을 경우 수역에서의 저층수의 거동재현에 있어서 더욱 효과가 있음을 볼 수 있었다.

• 한국환경농학회지
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• 제35권2호
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• pp.143-147
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• 2016

BACKGROUND: Rice fields are one of the most important habitats for various bird species. The list of bird species occurred in rice fields in Korean peninsula have been documented. However, information of listed bird species is included not only rice fields but also other wetland habitats such as lakes, tidal flats and rivers. Therefore, the study was conducted to clarify the status of bird observed in rice fields of Korea.METHODS AND RESULTS: Birds using rice fields defined as birds which forage or rest on rice paddies, levees, ditches and farming roads. Birds using rice fields recorded as total 124 species belonging to 40 families. Anatidae and Scolopacidae were the best represented family, followed by Ardeidae, Accipitridae, Motacillidae and Emberizidae; 50% of species belonged to these six families. 18 of 124 endangered wild species, which designated threatened at the national scale, found in this study regions.CONCLUSION: Despite interest in birds using rice fields of Korean peninsula, knowledge of birds and rice fields there is extremely limited. We need more studies to understand and conserve for birds in rice fields of Korea.

• 환경영향평가
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• 제16권2호
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• pp.143-156
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• 2007

This study has researched the management status and the pollution level of water, soil, stream sediments of 11 abandoned coal mines out of a total of 12 within Obong-Dam area except Bukyung mine, which was submerged when constructing Obong-Dam, and selected areas which are in needs to have pollution control facilities in the first place. From the results of examination on the runoff at the waste rock pile and mineheads, the runoff from Sueun mine (pH, Fe, Al), Samwon mine (pH, Al), Wangdo mine (pH, Al), Mose mine (pH, Fe, Al) and Daeryeong mine (pH) exceeded the permissible discharge standards of the water quality, but the water at merging point with Obong-Dam after joined with Doma branch satisfied both Water Quality Standards and Drinking Water Quality Standards. In regard to groundwater contamination, it is found that areas where exceeded the Drinking Water Quality Standards are Wangdo mine (pH), Jangjae mine (pH, Zn), Daeryeong mine (pH) whereas all areas satisfied Soil Contamination Warning Standards of Soil Environmental Conservation Law. When comparing a research result on underwater sediments of branches of abandoned mines to the EPA Guidelines for classification of great lakes harbor sediments, Dongguk Gaerim (Fe), Jungwon mine (Fe), Daebo mine (Mn), Samwon mine (Mn) and Daeryeong mine (Mn) showed mid-level of contamination, whereas Sueun (Fe, Mn), Daebo mine (Fe), Woosung mine (Fe, Mn), Wangdo mine (Fe, Mn), Mose mine (Fe) and Daeryeong mine (Fe) showed high-level of contamination. In addition, contamination levels of underwater sediments in Wangsan and Doma branch where abandoned mine's branches merge together, Wangsan branch showed no contamination at all whereas Doma branch shows mid-level of contamination which reflect the Doma branch is affected by waste rock pile and minehead runoff of the abandoned mines in the Doma branch area. It is concluded that Mose mine and Sueun mine required treatment of acid mine drainage. and Wangdo, Jungwon, and Samwon mines were in need of mine tailing and erosion control work. The Samwon mine additionally required a control system for closed minehead runoff. Although the Samwon mine reached a high concentration of Al, Mn $Ca^{2+}$, $SO{_4}^{2-}$ in the runoff, the levels decreased after it was combined with a tributary. It has been concluded that after further monitoring of the cause of pollution, a preventive measure system may be needed to be built.

• 대한환경공학회지
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• 제30권9호
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• pp.907-912
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• 2008

본 연구는 지표수나 호소수 등에서 유기 및 무기오염물질의 저감을 위해 반응매질로서 사용되는 black shale 및 영가철의 수중의 무기인산염을 흡착제거하는 데 있어서의 정량적 특성을 알아보았다. 무기인산염의 회분식 흡착실험에는 갯벌에서 마련한 퇴적토, black shale, 영가철이 흡착제로 사용되었으며 인산염의 흡착에 미치는 영향을 공존 칼슘이온의 농도를 0, 1, 5 mM로 변화시켜 실험하였다. 칼슘이온의 공존과 함께 세 흡착제에 대한 인산염 농도감소를 빠른 흡착계수(k$_f$), 느린 흡착계수(k$_s$)과 침전계수(k$_p$)로 구성된 kinetic model을 이용하여 해석하였다. 등온흡착의 결과는 Langmuir와 Freundlich 모델을 적용하였으며 퇴적토, black shale, 영가철에 대한 Freundlich 모델의 K$_f$값은 각각 1.141, 7.721, 그리고 4.873였다. 공존하는 칼슘이온과의 침전가능성으로 인하여 kinetic model에서는 칼슘농도와 침전제거간의 상관관계가 있었으나 등온흡착식에서 인산염의 최대흡착량에는 칼슘농도가 영향을 미치지 않았다.

• Asian Pacific Journal of Cancer Prevention
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• 제15권1호
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• pp.375-380
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• 2014

This study examined the incidence rates of cancer cases (averages for 2006-2010) and relationships with environmental radioactivity levels. Soil and water samples were collected from provincial and district centers of Van city and the outdoor gamma doses were determined using a portable gamma scintillation detector. Gross alpha and beta, (226)Ra, (232)Th, and (40)K activities were measured in both tap water and soil samples. Although high rates of stomach and esophagus cancers have been reported previously in Van the underlying reasons have not hitherto been defined. Incidences of cancers were highest in the Gurpmar (326.0) and Ozalp (377.1) counties (p<0.001). As to the results of the gross alpha and gross beta radioactivity measurements in the drinking water, these two counties also had high beta radionuclide levels: Gurpmar ($140mBq/dm^3$) and Ozalp ($206mBq/dm^3$). Even if within the normal range, a relation between the higher rate of the incidence of stomach and esophagus cancers with that of the higher rate of beta radionuclide activity was clear. On Spearman correlation analysis, the relation between higher beta radionuclide levels and cancer incidence was found to be statistically significant (p<0.01). According to the results of the analysis, Van residents receive an average 1.86 mSv/y annual dose from outdoor gamma radiation, ingestion of radionuclides in the drinking water, and indoor $^{222}Rn$ activity. Moreover, gross alpha and beta activities were found to be extremely high in all of the lakes around the city of Van, Turkey. Further investigations with long-term detailed environmental radiation measurements are needed regarding the relationship between cancer cases and environmental radioactivity in the city of Van.

• Environmental Analysis Health and Toxicology
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• 제28권
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• pp.2.1-2.7
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• 2013

Objectives Tricalcium phosphate and calcium hydrogenorthophosphate are high production volume chemicals, mainly used as foodstuff additives, pharmaceuticals, lubricants, synthetic resin, and disinfectants. Phosphate has the potential to cause increased algal growth leading to eutrophication in the aquatic environment. However, there is no adequate information available on risk assessment or acute and chronic toxicity. The aim of this research is to evaluate the toxic potential of phosphate compounds in the aquatic environment. Methods An aquatic toxicity test of phosphate was conducted, and its physico-chemical properties were obtained from a database recommended in the Organization for Economic Cooperation and Development (OECD) guidance manual. An ecotoxicity test using fish, Daphnia, and algae was conducted by the good laboratory practice facility according to the OECD TG guidelines for testing of chemicals, to secure reliable data. Results The results of the ecotoxicity tests of tricalcium phosphate and calcium hydrogenorthophosphate are as follows: In an acute toxicity test with Oryzias latipes, 96 hr 50% lethal concentration ($LC_{50}$) was >100 (measured:>2.14) mg/L and >100 (measured: >13.5) mg/L, respectively. In the Daphnia test, 48 hr 50% effective concentration ($EC_{50}$) was >100 (measured: >5.35) mg/L and >100 (measured: >2.9) mg/L, respectively. In a growth inhibition test with Pseudokirchneriella subcapitata, 72 hr $EC_{50}$ was >100 (measured: >1.56) mg/L and >100 (measured: >4.4) mg/L, respectively. Conclusions Based on the results of the ecotoxicity test of phosphate using fish, Daphnia, and algae, $L(E)C_{50}$ was above 100 mg/L (nominal), indicating no toxicity. In general, the total phosphorus concentration including phosphate in rivers and lakes reaches levels of several ppm, suggesting that phosphate has no toxic effects. However, excessive inflow of phosphate into aquatic ecosystems has the potential to cause eutrophication due to algal growth.

• 대한환경공학회지
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• 제38권9호
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• pp.482-496
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• 2016

하천과 호수의 부영양화로 인하여 남조류가 대량으로 증식하게 되면 고유의 생물독소로 인한 위해뿐만 아니라 정수처리 과정에서 경제적 손실을 야기할 가능성이 있다. 현재 상용화되어있는 천연조류제거제인 M사의 W.H. 응집제(이하 W.H.)는 참나무 유래 성분의 살조 및 타감작용을 이용한 응집.부상공정을 통하여 조류를 사전에 제거함으로써 정수공정에 미치는 영향을 효과적으로 저감할 수 있다. 그러나, W.H.를 활용한 응집 부상공정은 정수처리의 전처리공정으로 적용된 사례가 없기 때문에 최적주입농도의 결정기법에 대한 보고 또한 전무한 실정이다. 본 연구에서는 (1) 한강에서 채취한 복합 조류와 (2) 남조류를 선택적으로 대량 배양하여 광조건 하에서 W.H. 투여량 및 조류농도 등의 여러 조건을 변화시키면서 Jar-test를 시행하여 응집 부상공정에서의 조류의 제거기작을 검토하였다. Jar-test 결과를 바탕으로 IBM-SPSS를 활용한 다중회귀분석을 실시하여 최적 W.H. 주입농도를 결정하기 위한 Chl-a 농도와 탁도를 변수로 하는 두 가지 선형식을 도출하였다. 또한 유입수질의 변동에 따라 W.H. 주입농도를 신속하게 결정하고 자동화할 수 있는 자동제어 로직의 프로토타입(Prototype)을 제시하였다.

• 한국전통조경학회지
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• 제31권1호
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• pp.1-12
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• 2013

한국의 전통 석가산(石假山)은 고려시대 창안되어 조선시대로 계승된 우리의 우수한 석정문화(石庭文化)이다. 이 연구는 고려시대와 조선시대 석가산 문화가 시대 흐름에 따라 석가산 내면에 어떠한 함의성(含意性)을 표상하며 계승되어 왔는지를 분석하였다. 고려시대 산악형 풍경을 모사해 창안한 한국의 전통 석가산은 괴석을 소재로 진산(眞山)을 모사한 작은 인공가산(人工假山)을 만들었다. 그리고 산수풍경을 축경적(縮景的)으로 재현하고 심산유곡의 흥취를 집안에서 와유(臥遊)하며, 풍류를 즐기는 동시에 정서적 안정과 치유라는 실용적 측면의 경물(景物)로서의 심미적 풍경의 산수체험을 석가산을 통해 경험하였다. 이러한 석가산은 내향적으로는 경물 자체의 형식미를 초월하며 불로장생을 염원하는 삼신산(영주, 봉래, 방장)과 도교적 신선사상이 응축된 오악(숭산, 태산, 화산, 항산, 형산)을 표상하며, 신선계(神仙界)를 이상향적으로 나타내고자 하였다. 또한 석가산을 대하며 유교의 요산요수(樂山樂水)의 교훈을 실천해 심성을 가다듬고, 중국의 명산명호(名山名湖)를 모방하는 등 석가산 내면에 다양한 함의성을 포용하며 변천, 발달하였다. 한국의 전통 석가산은 심미적 풍경의 산수체험은 물론 실용적 경물로서의 형식미를 초월하며, 석가산의 심오한 상징적 함의성을 표상하여 무한한 상상의 관념적 공간으로 승화시켰다.

• Journal of Microbiology and Biotechnology
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• 제30권10호
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• pp.1516-1524
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• 2020

Climate change is expected to affect not only availability and quality of water, the valuable resource of human life on Earth, but also ultimately public health issue. A six-year monitoring (total 20 times) of Escherichia coli O157, Salmonella enterica, Legionella pneumophila, Shigella sonnei, Campylobacter jejuni, and Vibrio cholerae was conducted at five raw water sampling sites including two lakes, Hyundo region (Geum River) and two locations near Water Intake Plants of Han River (Guui region) and Nakdong River (Moolgeum region). A total 100 samples of 40 L water were tested. Most of the targeted bacteria were found in 77% of the samples and at least one of the target bacteria was detected (65%). Among all the detected bacteria, E. coli O157 were the most prevalent with a detection frequency of 22%, while S. sonnei was the least prevalent with a detection frequency of 2%. Nearly all the bacteria (except for S. sonnei) were present in samples from Lake Soyang, Lake Juam, and the Moolgeum region in Nakdong River, while C. jejuni was detected in those from the Guui region in Han River. During the six-year sampling period, individual targeted noxious bacteria in water samples exhibited seasonal patterns in their occurrence that were different from the indicator bacteria levels in the water samples. The fact that they were detected in the five Korea's representative water environments make it necessary to establish the chemical and biological analysis for noxious bacteria and sophisticated management systems in response to climate change.