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Choi B.,Chungnam National University | Son M.,Yeongsan River Environment Research Center | Kim J.I.,Chungnam National University | Shin W.,Chungnam National University
Algae | Year: 2013

The genus Cryptomonas is easily recognized by having two flagella, green brownish color, and a swaying behavior. They have relatively simple morphology, and limited diagnostic characters, which present a major difficulty in differentiating between species of the genus. To understand species delineation and phylogenetic relationships among Cryptomonas species, the nuclear-encoded internal transcribed spacer 2 (ITS2), partial large subunit (LSU) and small subunit ribosomal DNA (rDNA), and chloroplast-encoded psbA and LSU rDNA sequences were determined and used for phylogenetic analyses, using Bayesian and maximum likelihood methods. In addition, nuclear-encoded ITS2 sequences were predicted to secondary structures, and were used to determine nine species and four unidentified species from 47 strains. Sequences of helix I{cyrillic, ukrainian}, I{cyrillic, ukrainian}I{cyrillic, ukrainian}, and I{cyrillic, ukrainian}I{cyrillic, ukrainian}I{cyrillic, ukrainian}b in ITS2 secondary structure were very useful for the identification of Cryptomonas species. However, the helix I{cyrillic, ukrainian}V was the most variable region across species in alignment. The phylogenetic tree showed that fourteen species were monophyletic. However, some strains of C. obovata had chloroplasts with pyrenoid while others were without pyrenoid, which used as a key character in few species. Therefore, classification systems depending solely on morphological characters are inadequate, and require the use of molecular data. © The Korean Society of Phycology.


Duong C.N.,Gwangju Institute of Science and Technology | Lee J.H.,South Korean National Institute of Animal Science | Lim B.J.,Yeongsan River Environment Research Center | Kim S.D.,Gwangju Institute of Science and Technology
Water Science and Technology | Year: 2011

The objective of this study was to investigate the ability of E. coli in river sediments to degrade estrogen conjugates. Biodegradation experiments on glucuronide estrogens (E1-GLU, E2-GLU and E3-GLU) using E. coli, non-E. coli bacteria as well as sediment crude extracts were carried out in batch mode. A pure identified E. coli strain (KCTC 2571) was used for comparison of enzyme activity. The results showed that the degradation rate of estrogen conjugates by KCTC 2571 and E. coli isolated from sediments followed a similar trend. Fecal bacteria showed a high ability to deconjugate glucuronided estrogens. Approximately 50% of glucuronide moieties were cleaved within 4 h of contact time in experiments using pure E. coli. The degradation rate was slower in experiments using crude extracts of sediments, and conjugated estrogens were not completely degraded even after 12 h of reaction. These results provide a clear understanding of the fate and behavior of estrogen by bacteria in the environment. © IWA Publishing 2011.


Ra J.-S.,Eawag - Swiss Federal Institute of Aquatic Science and Technology | Lee S.-H.,Gwangju Institute of Science and Technology | Lee J.,Gwangju Institute of Science and Technology | Kim H.Y.,Gwangju Institute of Science and Technology | And 3 more authors.
Journal of Environmental Monitoring | Year: 2011

Broad scale monitoring of estrogenic compounds was performed at 19 sampling points throughout the Yeongsan and Seomjin river basins and 5 wastewater treatment plants (WWTPs) adjacent to the Gwangju area, Korea, from December 2005 to August 2007. The concentrations of estrogenic compounds, including estrone (E1), 17β-estradiol (E2), 17α-ethynylestradiol (EE2), bisphenol-A, nonylphenol (NP) and 4-octylphenol (OP), in the samples was measured with gas chromatography/mass spectrometry (GC-MS). In addition, the estrogenic activities throughout the river were investigated using the E-screen assay. Of the six estrogenic chemicals, NP (114.6-336.1 ng L -1) and EE2 (0.23-1.90 ng L -1) were detected at the highest and lowest levels, respectively in both the river waters and the WWTP effluents. Bisphenol-A showed the largest concentration range, from 7.5 to 335 ng L -1. The concentrations of E1, E2 and octylphenol ranges were 3.6-69.1, 1.2-10.7, and 2.2-16.9 ng L -1, respectively. According to the calculated estradiol equivalent concentration (EEQ); however, no estrogenic contribution was observed due to the phenolic compounds in the river waters and effluents. E1 and E2 dominated in both the river water and effluent samples, with contributions to the calculated EEQ of over 79 and 77%, respectively. Conversely, EE2 was rarely detected in the river waters (21%) and effluents (0%). The largest contribution of EE2 to the calculated EEQ was 21% in the river water at S-7. The levels of E1, E2, and EE2 were remarkably decreased in the effluents, indicating that the 5 WWTPs did not contribute to the estrogenic effect of the receiving streams. Overall, the WWTPs did not contributed to the estrogenic activity of the receiving waters, but the livestock industry or wildlife may play an important role in the estrogenic contribution to river water. © 2011 The Royal Society of Chemistry.


Baek S.-S.,Ulsan National Institute of Science and Technology | Choi D.-H.,Chonnam National University | Jung J.-W.,Jeolla Namdo Environmental Industries Promotion Institute | Lee H.-J.,Yeongsan River Environment Research Center | And 3 more authors.
Water Research | Year: 2015

Currently, continued urbanization and development result in an increase of impervious areas and surface runoff including pollutants. Also one of the greatest issues in pollutant emissions is the first flush effect (FFE), which implies a greater discharge rate of pollutant mass in the early part in the storm. Low impact development (LID) practices have been mentioned as a promising strategy to control urban stormwater runoff and pollution in the urban ecosystem. However, this requires many experimental and modeling efforts to test LID characteristics and propose an adequate guideline for optimizing LID management. In this study, we propose a novel methodology to optimize the sizes of different types of LID by conducting intensive stormwater monitoring and numerical modeling in a commercial site in Korea. The methodology proposed optimizes LID size in an attempt to moderate FFE on a receiving waterbody. Thereby, the main objective of the optimization is to minimize mass first flush (MFF), which is an indicator for quantifying FFE. The optimal sizes of 6 different LIDs ranged from 1.2 mm to 3.0 mm in terms of runoff depths, which significantly moderate the FFE. We hope that the new proposed methodology can be instructive for establishing LID strategies to mitigate FFE. © 2015 Elsevier Ltd.


Baek S.-S.,Chonnam National University | Choi D.-H.,Chonnam National University | Jung J.-W.,Yeongsan River Environment Research Center | Yoon K.-S.,Chonnam National University | Cho K.-H.,Ulsan National Institute of Science and Technology
Desalination and Water Treatment | Year: 2015

Abstract: Adapting best management practices (BMPs) is influenced by target reduction efficiency BMP size, and BMP type. The System for Urban Storm water Treatment and Analysis INtegration (SUSTAIN) model was evaluated to determine optimal size and type of BMP with monitoring results from a commercial area and a public park in Korea. The hydrology model in SUSTAIN was tested in a commercial area (impervious area: 85%) and a public park (impervious area: 36%) in South Korea. A sensitivity analysis revealed that the significant parameters for total flow were impervious area Manning’s roughness (IMPN) and saturated hydraulic conductivity (HYDCON); and those for peak flow were IMPN, Manning’s roughness of conduit (ROUGH) and HYDCON. The observed average run-off ratios of the two study sites were 0.59 and 0.30 for the commercial area and the public park, respectively. In contrast, the simulated average run-off ratios were 0.53 and 0.22, respectively. The SUSTAIN hydrology model was also evaluated statistically by comparing observed and simulated run-off. In a commercial area, R2, root mean square error, and Nash–Sutcliffe efficiency were 0.68, 10.98, and 0.46, respectively, whereas the public park yielded 0.74, 1.97, and 0.62, respectively. After calibrating the model, the BMP options of SUSTAIN (i.e. bioretention, dry pond, and wet pond) were utilized to test run-off reduction capability with 11 mm of retaining run-off depth from the commercial area and 3 mm from the public park. Monitoring data showed that 11 and 3 mm run-off storage ensured about a 50% reduction of run-off from the commercial area and the public park, respectively. In the commercial area, average reduction rates were identically all 43.0% for bioretention, dry pond, and wet pond, respectively, and those for the public park were 49.6, 57.6, and 53.5%, respectively. Overall, the BMP function of SUSTAIN seemed to be reasonable for reducing run-off and could be used to design BMP to meet a target reduction goal where monitoring data does not exist. © 2014 Balaban Desalination Publications. All rights reserved.

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