• 한국물환경학회지
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• 제30권5호
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• pp.539-548
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• 2014

This study was carried out to investigate algal community structures and their correlations with environmental factors on five weir areas in the Nakdong River, South Korea. Water qualities, hydrodynamics, meteorological conditions and algal species compositions were observed in studied sites from May 2010 to Dec. 2013. Results showed that average total phosphorus concentration of 2013 was decreased by 52.4% in comparing with that from 2010 to 2011. Chlorophyll.a concentrations were positive significant with water temperature, pH, total phosphorus and total nitrogen, but is not significant with turbidity and suspended solids. Seasonal successions of algae were observed that Stephanodiscus sp. was dominant species with 65.3% of dominant frequency in studied site. Large algal biomass of the low temperature-adapted diatoms were observed during temperature range of $4{\sim}9^{\circ}C$, but large cyanobacterial biomass mainly during high temperature period ranged from $22^{\circ}C$ to $32^{\circ}C$. Microcystis sp. dominated during high water temperature in summer. The yearly correlations of algal biomass with accumulated solar radiations were not significant but seasonal correlations of summer from June to August were significant with correlation coefficient 0.33 (p<0.05). There were not significant correlations between turbidities and algal biomass. Turbidity and suspended solids concentrations were not significant correlation with algal biomass. According to the results, algal communities had strong correlation with water temperature and had partially correlation with solar radiation. For an effective management of algal blooms, water managers should survey with more long-term monitoring of various environmental factors and algal communities.

• 한국환경과학회지
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• 제10권1호
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• pp.21-25
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• 2001

The Keum river has been utilized for drinking water supply of several city including Kunsan city and is deepening pollution state due to numerous municipal and industrial discharges. The concentration BOD in river is affected by the organic loading from a tributary and the algae biomass that largely happen to under eutrophication state. In the eutrophic water mass such as the Keum river, the autochthonous BOD was very important part for making a decision of water quality management, because it was accounted for majority of the total BOD. The predict of water quality has important meaning for management of water quality pollution of the Keum river. The purpose of this study will manage and predict water quality of the Keum river using QUAL-2E model considering the autochthonous BOD. The estimation of autochthonous BOD represented that the relationship between BOD and chlorophyll a. The regression equation was shown to be autochthonous BOD=$\beta$(sub)5$\times$chlorophyll a. The results of this study may be summarized as followed; The QUAL-2E model was calibrated with the data surveyed in the field of the study area in June, 1998. The calculated value by QUAL-2E model are in good agree to measured value within relative error of 7.80~20.33%. Especially, in the case of the considering autochthonous BOD, the calculated value of BOD were fairly good coincided with the observed values within relative error of 15%. But the case of not considering autochthonous BOD, relative error of BOD was shown to be 43.2%. In order to attain II grade of water quality standard in Puyo station which has a intake facility of water supply, we reduced to the pollutants loading of tributaries. In the case of removed 100% BOD of tributaries, the BOD of Puyo station was 4.07mg/$\ell$, belong to III grade of water quality standard. But in the case of removed 88% nutrient of tributaries, it was satisfied to II grade of water quality standard as below 3mg/$\ell$ of BOD. For estimation of autochthonous BOD in Keum river, we are performed simulating in accordance with reduction of nutrient load(50~100%) under conditions removal 90% organic load. Occupancy of autochthonous BOD according to nutrient loading reductions were varied from 25.97~79.51%. Occupancy of autochthonous BOD was shown to be a tendency to increasing in accordance with reduction of nutrient loading. Showing the above results, the nutrient that one of the growing factor of algae was important role in decision of BOD in the Keum river. For the water quality management of the Keum river, therefore, it is necessary to considering autochthonous BOD and to construction of advanced sewage treatment plant for nutrient removal.

• 한국수자원학회논문집
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• 제35권2호
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• pp.149-159
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• 2002

삽교호유역에 위치한 19개 수질관측지점에서 측정된 월별수질자료를 이용하여 수질관측지점을 2개에서 7개의 수질특성으로 분류하였으며, 그에 따른 수질요인분석을 실시하였다. 군집분석결과 삽교호유역의 각 하천은 개개의 수질특성을 보이고 있으며, 삽교호, 삽효천, 무한천 및 곡교천의 4개 그룹으로 나눌 수가 있었다. 수질분석결과에 의하면 삽교호에서는 부유물질의 농도가 다른 하천보다 높았는데 이는 하천으로부터 유입되는 풍부한 영양염에 의한 식물플랑크톤의 생물량 증가에 따른 것으로 사료된다. 또한 곡교천의 수질은 다른 하천에 비해 생화학적산소요구량은 3.5∼4.8배, 화학적산소요구량은 1.7∼2.5배 높았으며, 전반적으로 삽교호 유역의 수질은 부영양상태를 훨씬 초과하였다. 요인분석결과 삽교천과 무한천은 농경지와 주거지에 의한 수질요인이 지배적이었고, 곡교천은 천안도시지역으로부터 유입되는 과다한 유기물유입과 상류에 위치한 하수처리장의 영향을 복합적으로 받고 있는 것으로 사료된다. 삽교호의 수질은 삽교천과 무한천및 곡교천에서 높은 부하를 보인 인자가 주된 오염요인으로 나타났다.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2006년도 추계학술발표회
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• pp.217-219
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• 2006

This study focused an water quality response to land-based pollution loads and the appropriate pollutant load reduction in Chinhae Bay using an eco-hydrodynamic model. Land-based discharge foam urban areas, industrial complex and sewage treatment plant was the greatest contributor to cause red-tide blooms and summer hypoxia. Tidal currents velocity af the ebb tide was about 10 cm/s stronger than that of the flood tide. A residual current was simulated to. have a slightly complicated pattern with ranging from 0.1 to. 2.7 cm/s. In Masan Bay, pollutant materials cannot flaw from the inner to the outer bay easily because af residual currents flaw southward at surface and northward at the bottom. The simulation results of COD distribution showedhigh concentrations aver 3 mg/L in the inner part of Masan Bay related pollutant discharge, and charge, and lower levels less than 1.5mg/L in the central part of Chinhae Bay. For improvement water quality in Chinhae Bay, it is necessary to reduce the organic and inorganic loads from paint sources by mare than 50% and ameliorate severe polluted sediment.

• Journal of Ecology and Environment
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• 제39권1호
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• pp.61-70
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• 2016

Major objectives of the study were to analyze chemical and biological influences of the river ecosystem on the artificial weir construction at three regions of Sejong-Weir (S_j-W), Gongju-Weir (G_j-W), and Baekje-Weir (B_j-W) during 2008-2012. After the weir construction, the discharge volume increased up to 2.9 times, and biological oxygen demand (BOD) and electrical conductivity (EC) significantly decreased (p < 0.05). Also, the decrease of total phosphorus (TP) was also evident after the weir construction, but still hyper-eutrophic conditions, based on criteria by , were maintained. Multi-metric model of Index of Biological Integrity (IBI) showed that IBI values averaged 21.0 (range: 20-22; fair condition) in the B_wc, and 14.3 (range: 12-18; poor condition) in the A_wc. The model values of IBI in S_j-W and G_j-W were significantly decreased after the weir construction. The model of Self-Organizing Map (SOM) showed that two groups (cluster I and cluster II) of B_wc and A_wc were divided in the analysis based on the clustering map trained by the SOM. Principal Component Analysis (PCA) was similar to the results of the SOM analysis. Taken together, this research suggests that the weir construction on the river modified the discharge volume and the physical habitat structures along with distinct changes of some chemical water quality. These physical and chemical factors influenced the ecosystem health, measured as a model value of IBI.

• 생태와환경
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• 제41권3호
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• pp.311-319
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• 2008

저온기 부영양 수계의 규조군집 특성과 이들의 유입능을 이해하기 위하여, 2008년 1월 15$\sim$29일까지 한강과 일감호에 인공기질을 15일 동안 설치하고, 환경요인과 규조류 유입능을 각각 조사하였다. 조사결과, 유속이 높을수록 수중의 영양염은 감소하였으나 설치된 기질의 유기물과 Chl-a는 유사한 변화 패턴을 나타냈다. 두 수계에서 가장 높은 빈도를 보인 우점 조류는 각각 Navicula sp. (한강)와 Synedra acus (일감호)이었으며, 가장 높은 유입능을 보인 조류는 각각 Nitzschia amphibia (한강)와 Aulacoseira italica (일감호)로 나타났다. 한강에서 조류의 유입능은 영양염, 유기물, Chl-a 등이 높고 유속이 낮을수록 높게 나타났으며, 일감호에서는 영양염이 높고 수생식물이 없는 곳에서 높았다. 결국, 저온기 규조류의 유입능은 하천에서는 영양염과 유속, 호수에서는 수생식물의 발달 여부에 따라 크게 영향을 받는 것으로 사료되었다.

• Ecology and Resilient Infrastructure
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• 제5권3호
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• pp.174-179
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• 2018

$TiO_2$-embedded expanded polystyrene (TiEPS) balls with powdered $TiO_2$ particles embedded on the surface of EPS were developed, and the growth inhibition of Chlorella ellipsoidea, a green algae, was evaluated. The experiment was conducted using four reactors with various conditions of (A) natural sunlight, (B) natural sunlight + TiEPS balls, (C) dark, and (D) dark + TiEPS balls on the roof of the building during five days. Based on the analysis of cell number, cell morphology, concentrations of chlorophyll-a and phaeopigments, both surface reactions in heterogeneous photocatalysis and light shielding could inhibit the growth of C. ellipsoidea. The highly reactive hydroxyl radicals ($OH{\cdot}$) from TiEPS balls degraded the lipid cell membrane through the peroxidation reaction with the light shielding, eventually resulting in cell inactivation. Although dominant inhibitory effects on the growth of C. ellipsoidea were ambiguous, TiEPS balls were feasible to prevent and inhibit the excessive growth of algae in eutrophic water body.

• 한국물환경학회지
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• 제24권5호
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• pp.550-555
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• 2008

This study was conducted to assess the growth characteristics of phytoplankton and to understand seasonal dynamics of phytoplankton in response to limiting nutrients in an agricultural reservoir from November 2002 to December 2003. Marked increase of chl.a concentration observed in July ($99.0{\mu}g/L$) and November ($109.7{\mu}g/L$) after heavy rainfall. TP concentration ranged $48.0{\sim}126.6{\mu}g/L$, and its the temporal variation was similar to that of chl.a concentration. Microcystis spp., dominant phytoplankton species were used for the growth kinetics experiment, except for the season when Aulacoseira spp. (March, April) and Aphanocapsa sp. (May) dominated. In the temperature range between $10{\sim}25^{\circ}C$, the rate of growth increase per $10^{\circ}C$ was almost two folds. The highest maximum growth rate (${\mu}_{max}=1.09day^{-1}$) of phytoplankton observed September, and ${\mu}_{max}$ was lowest ($0.34day^{-1}$) in March when Aulacoseira spp. dominated. The ${\mu}_{max}$ ($0.78{\pm}0.20day^{-1}$) was relatively high in the summer season when water temperature is above $20^{\circ}C$ and cyanobacteria dominated compared to the spring when diatoms dominated ($0.43{\pm}0.08day^{-1}$). The maximum growth rate ($0.55{\pm}0.12day^{-1}$) and the half saturation concentration ($K_s=0.73{\pm}0.15{\mu}M$) of cyanobacteria during winter season (November, December) was higher than those of diatoms. However, the ${\mu}_{max}$ and $K_s$ of cyanobacteria in December was similar to those of diatom, reflecting that diatom cell quota (Mean 48.4 pgP/cell) was greater than cyanobacteria (34.0 pgP/cell) during this time.

• 환경생물
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• 제31권4호
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• pp.233-242
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• 2013

Cyanobacteria (blue-green algae) are not only the first oxygenic organisms on earth but also the foremost primary producers in aquatic environment. Massive growth of cyanobacteria, in eutrophic waters, usually changes the water colour to green and is called as algal (cyanobacterial) bloom or green tide. Cyanobacterial blooms are a result of high levels of primary production by certain species such as Microcystis sp., Anabaena sp., Oscillatoria sp., Aphanizomenon sp. and Phormidium sp. These cyanobacterial species can produce hepatotoxins or neurotoxins as well as malodorous compounds like geosmin and 2-methylisoborneol (MIB). In order to solve the nationwide problem of hazardous cyanobacterial blooms in Korea, the following technically and strategically sound approaches need to be developed. 1) As a long-term strategy, reduction of the nutrients such as phosphorus and nitrogen in our water bodies to below permitted levels. 2) As a short term strategy, field application of combination of already established bloom remediation techniques. 3) Development of emerging convergence technologies based on information and communication technology (ICT), environmental technology (ET) and biotechnology (BT). 4) Finally, strengthening education and creating awareness among students, public and industry for effective reduction of pollution discharge. Considering their ecological roles, a complete elimination of cyanobacteria is not desirable. Hence a holistic approach mentioned above in combination to addressing the issue from a social perspective with cooperation from public, government, industry, academic and research institutions is more pragmatic and desirable management strategy.

• 한국수자원학회논문집
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• 제46권4호
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• pp.413-424
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• 2013

오염발생부하량을 억제하고 환경 친화적으로 지역을 개발할 수 있는 유역중심의 수질관리정책으로 수질오염 총량관리제를 도입하게 되었다. 하지만 총량 관리제의 시행에도 불구하고 낙동강 주요지천인 남강 하류부의 수질이 2005년 이후 지속적으로 악화되고 있는 실정이다. 남강 하류수계는 주변의 도시와 산업지역에 비점오염원이 산재하고, 하류수계의 물의 흐름이 더욱 완만해짐에 따라 수질 악화가 가속화되고 부영양화 현상이 발생되고 있다. 부영양화된 수역에서 BOD 농도는 유역으로부터 발생한 미처리 하수가 수역으로 유입되는 영향도 있지만 하천내에서 미처리된 영양염을 이용한 식물플랑크톤의 생산에 의해 공급되는 자생 BOD의 영향도 크게 작용한다. 남강하류의 수질관리를 위해서 유입 BOD와 자생 BOD의 기여도를 파악하여 오염 원인물질을 줄이기 위한 수질관리 방안이 설정되어야 한다. 본 연구에서는 조류생산 및 사멸에 의한 내부생산 유기물 증가를 고려하도록 국내에서 개발된 QUALKO2와 미국 EPA의 QUAL2E를 이용하여 자생 BOD의 영향을 분석하였다. QUALKO2 모형에서Chl.a의 영향을 받는 구간에서 BOD 농도가QUAL2E 모형의 BOD 농도보다 증가하고, 실측값과의 상관관계를 분석해 본 결과 QUALKO2 모형에서 상관관계가 높게 나타났다. 남강 하류의 수질악화 문제를 해결하기 위하여 댐 방류량의 증가와 하수처리장 방류수질 개선 등에 의한 Chl,a의 저감 방안을 모색하여 자생 BOD를 관리할 수 있을 것이다.