• 한국물환경학회지
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• 제26권1호
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• pp.125-132
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• 2010

Characterization of sediment quality is important for the proper management of surface water quality, yet sediment has not been monitored sufficiently. In this study, fecal indicator microorganism concentrations of sediments in the Geum River Basin were monitored. Sampling was carried out at one paddy field, one lakeshore and five monitoring stations in the lower reach of the Geum River Basin. Surface waters and sediments were sampled four times during rainy season. Total coliform concentrations of sediments were 12 times higher in average to those of surface waters while E. coli concentrations of sediments were six times higher. No correlation found between indicator microorganism concentration between surface waters and sediments.

• Ocean Systems Engineering
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• 제13권3호
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• pp.313-324
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• 2023

The vertical distribution of suspended sediments in the mangrove-mud coast is complicated due to the characterization of cohesive sediment properties, and the influence of hydrodynamic factors. In this study, the time-evolution of suspended sediment concentration (SSC) in water depth is simulated by a one-dimensional model. The model applies in-situ data measured in October 2014 at the outer station in Cu Lao Dung coastal areas, Soc Trang, Vietnam. In the model, parameters which have influence on vertical distribution of SSC include the settling velocity Ws and the diffusion coefficient Kz. The settling velocity depends on the cohesive sediment properties, and the diffusion coefficient depends on the wave-current dynamics. The settling velocity is determined by the settling column experiment in the laboratory, which is a constant of 1.8 × 10^-4 ms^-1. Two hydrodynamic conditions are simulated including a strong current condition and a strong wave condition. Both simulations show that the SSC near the bottom is much higher than ones at the surface due to higher turbulence at the bottom. At the bottom layer, the SSC is strongly influenced by the current.

• 한국수산과학회지
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• 제44권3호
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• pp.207-215
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• 2011

An endosulfan degrading bacterial strain, K-1321, was isolated by endosulfan-enrichment culture from a seaside sediment collected at Dadaepo Beach, Busan, Korea. The strain was identified as a Serratia sp. based on the results of morphological, biochemical and 16S rDNA homology analyses. Serratia sp. K-1321 was able to completely degrade 50 ppm endosulfan in culture media and soil within 6 weeks at $25^{\circ}C$. GC/MS analysis revealed that endosulfan diol was an intermediate of the bacterial endosulfan degradation. Considering the above results, we concluded that Serratia sp. K-1321 utilized endosulfan as a carbon source and metabolized endosulfan via a less toxic pathway, such as the formation of endosulfan diol as an intermediate.

• 한국물환경학회지
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• 제22권5호
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• pp.838-845
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• 2006

Characterization of sediment in the riverbed is of importance for effective water quality management, yet have not been monitored sufficiently. This paper reports monitoring results of nutrient concentrations of sediments. Surface waters and sediments were sampled four times during rainy season at five monitoring points. Organics of overlying water were increased after high flow condition followed by decreasing tendencies. Soluble phosphorus fraction among total phosphorus was increased after high flow condition while total phosphorus was in decreasing tendencies. Monitoring result suggested that more extended monitoring scheme for flow rate, scouring velocity, and suspended material is required for analyzing relationship between water quality and sediment.

• Advances in concrete construction
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• 제4권1호
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• pp.15-26
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• 2016

In Algeria, wastes are often stored in such conditions that do not meet standards. Today and more than ever, we really must implement an environmentally management of wastes. Recovery of waste in Algeria has a considerable delay due to the absence of a policy favorable to the development of waste management. But many researchers have shown the possibility to reuse dredged sediments in road construction. Through Europe, recent research works have been already performed on dam sediments. Present study fits into the context of the valorization of dredged sediments from Fergoug dam. They are found in considerable quantities and mainly composed of mineral phases, organic matters and water. The reservoir sedimentation poses problems for the environment and water storage, dredging becomes necessary. Civil engineering is a common way of recycling for such materials. Dredged sediments have not the required mechanical characteristics recommended by the standards as GTR guide (LCPC-SETRA 1992). So as to obtain mechanical performance, dredged sediment can be treated with cement, lime, or replaced materials like quarry sand. An experimental study has been conducted to determine physical and mechanical characteristics of sediments dredged from dam. Then different mixtures of sediment and/or quarry sand with hydraulic binders are proposed for improving the grain size distribution of the mixes. Finally, according these mixtures, different formulations have been tested as alternative materials with dredged sediments.

• 대한환경공학회지
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• 제33권1호
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• pp.9-15
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• 2011

농업 및 위락용으로 유지용수를 공급받는 군산 미제저수지의 수질 및 퇴적물 오염현황을 파악하고 퇴적물용출, 비점 오염원 및 외부공급수 등 세가지 영양염 유입경로별 오염부하를 비교 분석하였다. 수질분석결과 하절기에 수질이 크게 저하되고 부영양화에 따른 녹조현상이 가장 활발히 나타났으며, 부영양화지수 TSI (secchi depth)는 53.6, TSI (chlorophyll-a)은 57.7 및 TSI (TP)도 56.7로 모두 50 이상의 부영양호 상태를 보였다. 퇴적물오염도 조사결과 조사시기(계절)별 퇴적물 총질소(T-N)함량, 총인(T-P)함량 및 유기물함량의 각 평균은 통계학적으로 유의한 차이가 없는 것으로 나타났으나 시료채취 지점별 평균은 유의한 차이를 나타내 공간적 변화가 뚜렷하였다. 반면, T-N 및 T-P 퇴적물용출율결과는 공간적변화보다 시기별 변화가 뚜렷하였다. 수질 및 퇴적물 데이터의 상관성분석결과, 수질 T-N은 퇴적물 T-N함량 및 퇴적물 유기물함량과 통계학적으로 유의한 상관관계가 있었으나 수질 T-P는 통계학적으로 상관성을 보이는 인자가 확인되지 않았고 퇴적물 영양염 용출율 역시 수질과 통계학적으로 상관성을 보이는 인자가 확인되지 않았다. 미제저수지내 유입경로별 영양염오염부하 산정결과, T-N의 경우 외부 공급수에 의한 오염부하가 월등히 높게 나타났고 T-P의 경우 퇴적물용출부하와 외부 공급수 유입부하는 유사하고 비점유입부하가 상대적으로 적게 나타났다. 미제저수지의 수질개선을 위해서는 영양염오염부하가 상대적으로 높은 외부 공급수(금강호 양수)에 대한 대책이 우선적으로 수립되어야 하며 아울러, 퇴적물로부터 T-P용출을 저감시키는 수질오염저감대책이 필요한 것으로 판단된다.

• 한국수산과학회지
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• 제40권5호
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• pp.282-287
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• 2007

Chloroanilines are aromatic amines used as intermediate products in the synthesis of herbicides, azo-dyes, and pharmaceuticals. 3,4-dichloroaniline (DCA) is the degradation product of some herbicides (diuron, propanil, and linuron) and of trichlorocarbanilide, a chemical used as an active agent in the cosmetic industry. The compound, however, is considered a potential pollutant due to its toxicity and recalcitrant property to humans and other species. With the increasing necessity for bioremediation, we sought to isolate bacteria that degraded 3,4-DCA. A bacterium capable of growth on 3,4-DCA as the sole carbon source was isolated from seaside sediment using a dilution method with a culture enriched in 3,4-DCA. The isolated strain, YM-7 was identified to be Pseudomonas sp. The isolated strain was also able to degrade other chloroaniline compounds. The isolated strain showed a high level of catechol 2,3-dioxygenase activity on exposure to 3,4-DCA, suggesting that this enzyme is an important factor in 3,4-DCA degradation. The activity toward 4-methylcatechol was 53.1% that of catechol, while the activity toward 3-methylcatechol, 4-chlorocatechol and 4,5-chlorocatechol was 18.1, 33.1, and 6.9%, respectively.

• The Korean Journal of Ecology
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• 제19권3호
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• pp.209-216
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• 1996

In order to identify the habitat characteristics of water shield (Brasenia schreberi), water quality and sediment characters were investigated. Water shield had peculial habitats such as old reservoir, developed basin-like reservior, a water depth within 1.5 m, constant water level, and thick sediment layer at the bottom. The species had very dense populations under the favorable growing conditions and occasionally grew together with Utricularia japonica. When water shield decreased, Nelumbo nucifera, Nuphar japonicum and Zizania latifolia increased. Natural populations of water shield need protection because it is endangered by the human activities and their harvest. The optimal conditions for the growth of water shield was near neutral pH. low conductivity and low turbidity. Therefore the input of pollutants should be controlled for its growth. The inorganic ion contents such as K, Mg, and Na were higher in the water shield growing area. Especially iron content of the sediments in the reservoirs with water shield was nearly five times as high as that in the reservoirs without water shield. thus iron might be one of the major limiting factors for the growth. It was considered that molybdenum can be another major factor because water shield is a nitrogen fixing plant.

• Journal of Microbiology and Biotechnology
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• 제26권1호
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• pp.120-129
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• 2016

An industrial complex in Wonju, contaminated with trichloroethene (TCE), was one of the most problematic sites in Korea. Despite repeated remedial trials for decades, chlorinated ethenes remained as sources of down-gradient groundwater contamination. Recent efforts were being made to remove the contaminants of the area, but knowledge of the indigenous microbial communities and their dechlorination abilities were unknown. Thus, the objectives of the present study were (i) to evaluate the dechlorination abilities of indigenous microbes at the contaminated site, (ii) to characterize which microbes and reductive dehalogenase genes were responsible for the dechlorination reactions, and (iii) to develop a PCE-to-ethene dechlorinating microbial consortium. An enrichment culture that dechlorinates PCE to ethene was obtained from Wonju stream, nearby a trichloroethene (TCE)-contaminated industrial complex. The community profiling revealed that known organohalide-respiring microbes, such as Geobacter, Desulfuromonas, and Dehalococcoides grew during the incubation with chlorinated ethenes. Although Chloroflexi populations (i.e., Longilinea and Bellilinea) were the most enriched in the sediment microcosms, those were not found in the transfer cultures. Based upon the results from pyrosequencing of 16S rRNA gene amplicons and qPCR using TaqMan chemistry, close relatives of Dehalococcoides mccartyi strains FL2 and GT seemed to be dominant and responsible for the complete detoxification of chlorinated ethenes in the transfer cultures. This study also demonstrated that the contaminated site harbors indigenous microbes that can convert PCE to ethene, and the developed consortium can be an important resource for future bioremediation efforts.

• Journal of Species Research
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• 제9권4호
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• pp.362-374
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• 2020

A total of 35 bacterial strains were isolated from various sediment samples. From 16S rRNA gene sequence similarities higher than 98.7% and the formation of a robust phylogenetic clade with the closest species, it was determined that each strain belonged to independent and predefined bacterial species. No previous official reports have described these 35 species in Korea. The unrecorded species were assigned to 6 phyla, 10 classes, 18 orders, 23 families, and 31 genera. At the genus level, the unrecorded species were affiliated with Terriglobus of the phylum Acidobacteria, as well as with Mycobacterium, Rhodococcus, Kineococcus, Phycicoccus, Agromyces, Cryobacterium, Microbacterium, and Arthrobacter; Catellatospora of the class Actinomycetia; Lacibacter of the class Chitinophagia; Algoriphagus and Flectobacillus of the class Cytophagia; Flavobacterium and Maribacter of the class Flavobacteriia; Bacillus, Cohnella, Fontibacillus, Paenibacillus, Lysynibacillus, and Paenisporosarcina of the class Bacilli; Bradyrhizobium, Gemmobacter, Loktanella, and Altererythrobacter of the class Alphaproteobacteria; Acidovorax of the class Betaproteobacteria; Aliiglaciecola, Cellvibrio, Arenimonas, and Lysobacter of class Gammaproteobacteria; and Roseimicrobium of the class Verrucomicrobia. The selected strains were subjected to further taxonomic characterization, including Gram reaction, cellular and colonial morphology, and biochemical properties. This paper provides detailed descriptions of the 35 previously unrecorded bacterial species.