• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.17 no.3
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• pp.160-180
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• 2012

We have studied the eukaryotic plankton species diversity to compare the community structure of fresh and brackish waters in the lower reaches of the Nakdong River using metagenomic methods. We constructed 18S rDNA clone libraries of total DNAs extracted from environmental water samples collected at Mulgeum (MG100929, fresh) and Eulsukdo bridge (ES, brackish). Through the steps of colony PCR, PCR-RFLP, sequencing and similarity analysis, we discovered the diverse species composition of eukaryotic plankton. Total 338 clones (170 at MG100929 and 168 at ES) were analyzed, and then we found 74 phylotypes (49 for MG100929 and 25 for ES). From the phylogenetic analysis, we confirmed various eukaryotic plankton of broad range of taxonomic groups, including Stramenopiles, Cryptophyta, Viridiplantae, Alveolata, Rhizaria, Metazoa, and Fungi. We also found several unreported species in Korea and candidates of new taxonomic entities at levels higher than genus. Especially, the cryptic species diversity including unreported phylotypes of Pirsonia (Stramenopiles) and Perkinsea (Alveolata) suggests that the molecular monitoring method can produce new informative biological data in monitoring the changes in the Nakdong River Mouth ecosystem.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.6B
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• pp.565-575
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• 2011

The purpose of this study was to quantitatively evaluate the expression of both multi-metric qualitative habitat evaluation index (QHEI) and biological integrity index (IBI) for artificial structures eco-artificial fish reef (EAFR) for fishes asylum and habitat. Especially, both experimental evaluation and biological verification were performed in Water and Environmental Center's outdoor test-bed of Korea Institute of Construction Technology located in Andong-city, Gyeongsangbuk-do. The experimental conditions reflecting the situation of domestic river include the flow rate (e.g., $0.0{\sim}1.5m\;s^{-1}$), the width (e.g., 1.0~3.0 m), the depth (e.g., 0.05~0.70 m), and variable bed materials. Both QHEI and IBI were monitored for 8 months from May to December 2010. Whereas QHEI values were highest at experimental points of the E~F with an average of 83.1, those were lowest at B~C with an average of 78.1. However, QHEI values inside EAFR were more than 98.9, regardelss of space and time, and indicated more than the highest good of the state (Good) in the habitat. Overally, IBI values showed similar trend with QHEI, but were 44.2 in the winter dry season, compared to 32.8 of QHEI values. IBI values Also, IBI values inside EAFR were greater than those at the experimental channel by 5.7 to 11.4% and 18.7 to 34.8% in flow and stagnant conditions, respectively, indicating that EAFR can secure asylum and habitat for fish during the dry season. For comprehensive aquatic ecosystem assessment, the experimental channel showed generally fair conditions (Fair~Good), whereas EAFR showed good conditions (Good), suggesting that EAFR can be applied to aquatic ecosystem restoration and improvement.

• Korean Journal of Ecology and Environment
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• v.51 no.1
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• pp.71-85
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• 2018

A recent topic of interest within ecology is ecosystem services that are importantly connected with biodiversity. Biodiversity is a fundamental component of ecological studies and has been the subject of many studies worldwide. However, studies on the diversity and distribution of freshwater fish were not undertaken in earnest until 2000, and the number of internationally available studies is therefore still limited. In this study, we used data from "The Survey and Evaluation of Aquatic Ecosystem Health (hereafter SEAEH)" within the framework of which whole water systems on the Korean peninsula are annually monitored to investigate and determine the current status of the diversity and distribution of freshwater fish, as well as to elucidate major factors impacting freshwater fish. A total of 130 species from 28 families were identified at around 953 sites in the SEAEH investigation of 2014. The species Zacco platypus (relative abundance: 28.2%) and Z. koreanus (19.3%) were identified as the most abundant species on the Korean peninsula, and besides these 20 endangered species, 51 endemic species and 4 exotic species were also collected. Highest (96 species) and lowest (72 species) diversity were identified in the Han River Watershed and the Yeongsan/Seomjin River Watershed, respectively. The mean endemic rate was 32.7%, which is higher than the previous rate determined in 1995. The exotic species Micropterus salmoides, Lepomis macrochirus and Carassius cuvieri were found in the whole river system except north Yeongdong, whereas Oreochromis niloticus occurred only at three sites due to the cold water temperatures in winter. Totally, 28 species were found to be translocated to different water systems not connected with known original habitats, most translocations occurring in the Nakdong River and the Yeongdong region. Among the translocated species, Opsariichthys uncirostris amurensis, and Erythroculter erythropterus were dominantly distributed in the mid- to lower reaches of Nakdong River where they may be harmful to the native fish assemblages due to their strong predation. The construction of weirs in connection with the "4 River Project" generated changes in fish assemblages before, during and after the project, resulting in altered habitat condition. Especially, a decrease in the number of endemic species and an increase in the abundance of lentic species were seen. Human-induced global warming will allow exotic species requiring high water temperatures to adapt to the environmental conditions of the Korean peninsula, which may enhance the diversity of native fishes and create changes in distribution. For the establishment of realistic and efficient management and protection strategies for Korean freshwater fish, SEAEH, which produces fundamental and quantitative data for Korean streams, is an important and necessary tool.

• Journal of Environmental Policy
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• v.10 no.4
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• pp.61-80
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• 2011

Through concentrated investments in environmental regulations centered around BOD, which is a biodegradable matter index, and basic environmental infrastructures, national BOD pollution level has continuously improved. Nonetheless, limitations of BOD management system has become evident through nation-wide stagnation and/or increases of refractory organic matters, such as COD, at main drinking water sources, and the need for a new index, which can easily indicate different environmental conditions, has increased. Therefore, this study suggests a new organic management index for a proper management of surface water. $COD_{Cr}$ and TOC were examined as candidates for surface water quality management index, and it was found that TOC was more appropriate than $COD_{Cr}$ as an organic matter management index. Through this study, it was found that TOC possesses following qualities: a more representative index; international acceptability; monitoring program is easier; better availability of analysis techniques; better accuracy and precision of analysis; less time required for analysis; ease of operation; management of disinfection byproducts; connection with present policies; existence of foreign and domestic application case studies; and correlation with water ecosystem.

• Journal of Wetlands Research
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• v.10 no.1
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• pp.69-75
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• 2008

Toll-gate in highways often received the pollution impact from transportation/vehicular activities. Thus, concentrated pollutants carried by stormwater runoff are directed to nearby streams affecting the water quality and ecosystem. In order to determine the environmental impact on nearby waterbodies and predict the future impact by stormwater runoff, the unit pollutant loads from various landuses are really important. This research was performed to characterize the stormwater runoff and to provide the unit loads from Toll-gate landuses in Korea. The monitoring was conducted at toll gate locating in Gaeryoung City during 2006-2007. The water quality parameters including TSS, COD, DOC, TN, and TP were analyzed and also the flow rates were measured during the monitoring. In this paper, EMCs will be calculated by using the monitored water quality concetraions and flow rates, which will be used to determine the unit pollutant loads from the toll-gate of highway.

• Journal of Korean Society on Water Environment
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• v.28 no.6
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• pp.896-901
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• 2012

In this research, the levels of concentrations from the junction of effluent from wastewater treatment plant during dry days and combined with runoff from the surrounding 11 ha livestock catchment area during wet days were determined to investigate the relationships of the concentration of various pollutants such as particulates, nutrients and organics originating from point and nonpoint sources. Manual sampling was conducted from October 2008 to December 2011 during dry and wet days. Based on the results, the flow rates and concentrations of most pollutant parameters were increased during wet days. It was found out that the effluent wastewater combined with stormwater runoff has low BOD to TN/TP ratio and high TN/TP to BOD ratio. Therefore, it is needed to employ other treatment methods to effectively manage the wastewater and reduce the pollutant discharge to receiving water bodies.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.546-546
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• 2015

현재 새만금 호 내로 유입되는 만경, 동진강 유역은 대규모 관개시스템을 통해 하천수의 대부분을 농업용수로 취수하고 있어 하천의 건천화가 심화되고 이에 따라 수질관리와 수생태계 보전에 어려움이 있다. 또한 새만금호는 방조제 완공 이후 배수갑문을 통한 해수유통이 줄어들어 호 내중 하류부에만 영향을 미치고 상류부인 만경, 동진강의 유입부는 유입되는 유량과 오염부하량의 지배적인 영향을 받는다. 이러한 새만금유역과 호에 대해 적정수질유지 및 합리적인 수질관리 대책 수립이 중요하며, 이를 위하여 상류하천 및 새만금호의 주요 지점에 대한 지속적인 모니터링 및 유역과 수역의 기작 등을 합리적으로 구현할 수 있는 수질예측 모델을 구축, 운영 할 필요가 있다. 따라서 본 연구에서는 새만금유역에 대해 SWAT모형을 적용시켜 자료를 구축하였고, 그 결과를 토대로 3차원 수리?수질모델인 EFDC를 이용하여 2020년 호 내 수질을 모의하였다. 또한 제수문 방류조건(1cms방류, 65%방류, 전량방류)에 따른 수질 변화를 모의하여 호 내 수질변화와 영향범위를 추정하였다. 제수문에서의 1cms방류조건과 전량방류조건을 모의하여 연평균 농도를 비교 한 결과 M3지점에 서 COD 1.304mg/L 감소, T-N 1.207mg/L 감소, T-P 0.08mg/L 감소, Chl-a $5.095mg/m^3$ 감소, D3지점에서 COD 0.492mg/L 감소, T-N 0.205mg/L 감소, T-P 0.009mg/L 감소, Chl-a $2.117mg/m^3$ 감소하는 것으로 예측되어 수질이 개선되는 것으로 나타났다. 이는 만경강과 동진강 제수문의 증가된 방류량으로 인해 유황이 개선되고 호 내 오염부하농도가 감소하는 것으로 판단된다. 방류조건별 영향범위를 살펴본 결과, 65%방류조건에서는 호 내 상류구간에 영향을 미치는 것으로 나타났고, 전량방류조건에서는 호 내 중?상류구간이 지배적인 영향범위로 평가되었다. 따라서 유역 내 제수문 관리를 통한 방류량 조정은 새만금호의 효과적인 수질관리에 기여 할 것으로 예상되며, 향후 제수문의 체계화된 운영방안 수립대책이 필요하다.

• Environmental Analysis Health and Toxicology
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• v.24 no.3
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• pp.241-249
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• 2009

Heavy metal contaminants on the aquatic environment are of interest because they can have severe effects on economy and public health. Recently, the studies for monitoring of heavy metals try to do on aquatic system to assess safety and health of ecosystem by heavy metals. Thus, biological responses were investigated on Korean fairy shrimp Branchinella kugenumaensis exposed to cadmium (Cd) or copper (Cu) for long-periods (30 days). The survival rate decreased significantly (p<0.05) on B. kugenumaensis exposed to Cd and Cu at all concentrations. Especially, the highest decrease was observed at the relatively high concentration of Cd and Cu (p<0.01) and the response by Cd exposure was at dose-dependent. The growth rates were also decreased significantly (p<0.05) on B. kugenumaensis exposed to Cd and Cu for at all concentrations. Then, the reproduction rate, numbering cyst, was decreased significantly (p<0.01) on B. kugenumaensis after Cd or Cu exposures. Long exposure of the relatively high concentration Cd and Cu can have severe effects on the reproduction, while exposures of Cd and Cu can not have effects on sex ratios of B. kugenumaensis. Additionally, asymmetric telson deformity was only observed after Cd exposure. Therefore, these results suggest that B. kugenumaensis is a sensitive bio-indicator of heavy metal exposure and these biological responses of B. kugenumaensis give important information for long-term monitoring on aquatic ecosystem.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.203-203
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• 2019

도시화로 인한 불투수면의 증가는 물순환 왜곡, 비점오염원 발생 및 수생태계 건상성 훼손 등을 야기시키며, 이를 해결하기 위하여 다양한 LID 기법을 적용하고 있다. 일반적으로 LID 내 적용 되는 여재들은 무기성여재로 중량이 크고 미세공극의 부재로 물리화학적 및 생물학적 저감기능이 제한적이다. 따라서 본 연구에서는 중량성이 낮은 생물폐자원을 선정하여 LID 시설 적용성평가를 수행하고자 한다. 생물폐자원은 발생량, 경량성 및 용이성을 고려하여 꼬막껍질(CS)과 호두껍질(WS)을 선정하였다. 생물폐자원의 산화부식을 고려하여 무기성 여재인 화산석과 혼합하여 Bioretention 시설에 적용하였으며, 여재 혼합비율에 따라 총 3가지의 Case 로 구성하였다. 식생은 구절초와 꽃댕강나무를 식재하였으며, 여재의 물리적 특성 분석을 위하여 적용 전과 후의 SEM(Scanning Electronic Microscope)을 수행하였다. 모니터링은 도로퇴적물 100g과 물 110L를 제조하여 인공강우유출수를 이용하여 수행하였으며, $0.0003{\sim}0.007m^3/sec$의 유속으로 주입하였다. 시설의 유입 및 유출부에서 유량 측정 및 수질 시료를 채취하였으며, 채취된 시료는 수질오염공정 시험법에 준하여 입자상 물질, 유기물, 영양물질 및 중금속 등을 분석하였다. Bioretention 시설의 모니터링 결과를 이용하여 물수지 및 TSS 저감 효율을 산정하였으며. 물수지 분석결과 시설의 저류율은 Case 1(soil) > Case 3(WS+RV) > Case 2(CS+RV) 순으로 나타났다. 시설 내 공극률이 가장 낮았던 Case 1에서 저류율이 약 55%로 가장 높게 것으로 분석되었다. Case 3(WS+RV)은 Case 2(WS+RV)와 시설 내 공극률이 유사함에도 불구하고 저류율이 약 10% 높은 것으로 분석되었다. 오염물질 저감효율 분석 결과, TSS와 TP의 제거효율은 모든 Case에서 약 75% 이상으로 높게 나타났으며, COD의 경우 모래를 적용한 Case 1에 비해 생물폐자원인 꼬막껍질과 호두껍질을 적용한 Case에서 약 1.3배 이상 높게 나타났다. 호두껍질과 꼬막껍질의 SEM 분석 결과 표면에 다공성이 형성되어 있는 것으로 조사되었다. 이는 여과 및 저류기작으로 인한 물순환 효과증대와 다공성과 돌기사이로 인한 입자상의 물질 여과 및 흡착으로 인하여 오염물질의 제거효율이 증대 된 것으로 평가된다. LID시설 내 생물폐자원과 무기성여재를 적절히 배합하여 복합여재로 조성할 경우 침하현상을 방지할 뿐만 아니라 저류 및 침투기능 향상과 미생물의 서식환경을 제공하기에 물순환 회복 및 비점오염물질 저감에 기여할 것으로 평가된다.

• Ecology and Resilient Infrastructure
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• v.4 no.2
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• pp.105-114
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• 2017

This study performed physical habitat simulation for fish and macroinvertebrate species in the Gongneung River. Target fishes were selected as Rhinogobius brunneus and Zacco platypus. Target macroinvertebrate species were selected as Hydropsyche kozhantschikovi and Chironomidae. Habitat suitability curves were constructed by using monitoring data from the monitoring project which is called "the survey and evaluation of aquatic ecosystem health". For calculation of CSI, weighted mean method was used. For macroinvertebrates species, the weighting factor derived from analytic hierarchy method was considered. River2D, which is capable to simulate flow in two-dimensional space, was selected for flow computation. Composite suitability index was simulated for target fish and macroinvertebrate species for discharge of drought, low, normal, and averaged-wet flow. Simulation results show that Chironomidae and Hydropsyche kozhantschikovi prefer the pool and riffle habitat, respectively. Rhinogobius brunneus and Zacco platypus show high suitability in riffle habitat.