• Journal of the Korean Chemical Society
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• v.43 no.6
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• pp.644-650
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• 1999

Trace amount of cobalt in water samples was preconcentrated continuously with an organic precipitant and determined by flame atomic absorption spectrometry. The flow injection technique was used to preconcentrate cobalt by on-line direct precipitation with 1-nitroso-2-naphthol. The precipitation was dissolved with methyl isobutyl ketone (MlBK) and was sent to the flame. The optimum conditions for cobalt determination were determined and used to analyze Co samples. For 1.0 mL of sample, the enrichment factor was 13 and the sample throughput was about lO per hour for 0.5 ppm Co solution. The enrichment factor was increased to 68 fold for 10.0 mL. A semi-reference biologicaI sample was prepared and analyzed. The result was in good agreement with the expected value with RSD of 4%.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.5
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• pp.626-637
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• 2013

We measured the grain size, ignition loss (IL), chemical oxygen demand (COD), acid volatile sulfide (AVS) and trace metals (Al, Fe, Cu, Pb, Zn, Cd, Cr, Mn, Hg, and As) of intertidal surface sediment collected from 11 islands (62 stations) in the southern region of Jeollanam Province. The objective of this research was to evaluate the organic matter and trace metals contaminations of sediments from coastal island tidal flats. Surface sediment texture was characterized as follows: mud, sandy silt, muddy sand, and slightly gravelly sand facies. The finer sediments are mainly dominated in the northern part of each island. The concentrations of IL, COD, AVS and some trace metals (Al, Fe, Zn, Cr, Cu, and Hg) were higher in the northwestern part of Wan Island and the area between Gogeum and Sinji Islands, and were associated with relatively finer sediment, as compared to other locations. The concentrations of Mn, Pb, Cd, and As were higher in the northwestern and southeastern parts of Geoguem and Pyungil Islands, but were not correlated with mean grain size. Based on sediment quality guidelines (SQGs), the concentrations of trace metals were lower than the values of effect range low (ERL), used in United States, and threshold effects level (TEL), used in Korea, with exception of As. Similarly, the intertidal sediments were moderately contaminated with As, based on the the enrichment factor (EF) and the geoaccumulation index ($I_{geo}$). The high concentration of As in intertidal sediments from this study region may be due to the input of naturally or artificially contaminated submarine groundwater, contaminated waste from seaweed aquaculture operations and/or land-based seaweed processing facilities. Further studies are needed to identify the sources of As in this study region, and to determine the effects of As contamination on coastal ecosystem.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.6
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• pp.772-784
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• 2011

We measured grain size, organic matter, and metallic elements (Fe, Cu, Pb, Zn, Cd, Cr, Mn, Hg, and As) in intertidal sediments collected from six islands in the western part of Jellanam Province in order to evaluate heavy metal contamination in the tidal flat sediments of coastal islands. The evaluation of metal contamination was carried out using geochemical assessment techniques such as sediment quality guidelines (SQGs), enrichment factor (EF), and geoaccumulation index ($I_{geo}$). Surface sediments were classified into four sedimentary facies: sand, gravelly muddy sand, slightly gravelly mud, and silt. The concentrations of heavy metals in intertidal sediments from Jaeun, Amtae, Biguem, and Docho islands showed good positive correlations with mean grain size and ignition loss, indicating that the concentrations of metallic elements in these sediments were dependent on grain size and the organic matter content. The concentrations of heavy metals in sediments from almost all of the stations were lower than two criterion values proposed by the National Oceanic and Atmospheric Administration (NOAA) in the United States. Based on the EF and $I_{geo}$ results, surface sediments were a little polluted for Cr and were moderately polluted for As. Our results suggest that more intensive studies are necessary in the future in order to determine the major source of As in intertidal sediment and to evaluate the As pollution level in macrobenthos.

• Korean Journal of Microbiology
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• v.52 no.2
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• pp.183-191
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• 2016

Marine bacteria have represented unique physiologies and products which are not discovered from terrestrial organisms. There has been great interest to utilize and develop marine bacteria in many industrial sectors. Recently, we isolated and characterized anaerobic bacteria from various marine environments in Korea to search organic acids fermenting strains. From our enrichment performed under anaerobic condition, 65 strains were isolated and identified by the 16S rRNA gene sequence analysis. Among them, eleven strains were selected for phylogenetical and biochemical analysis. All tested strains were affiliated with Class Clostridia except one with Class Bacteroidia. Most of strains produce acetate (6 strains) with butyrate (2 strains) and/or formate (4 strains). Strain MCWD5 transformed 40% of glucose to extracellular polymeric substances. These results indicate that many novel anaerobic microorganisms which have great potential in commercial application are distributed in the marine environments of Korean Peninsula.

• Journal of Life Science
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• v.21 no.5
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• pp.700-705
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• 2011

Using enrichment procedures, we isolated organic solvent-tolerant Bacillus sp. BCNU 5005 from waste water and soil in the Ulsan industrial plant region. BCNU 5005 had a maximum similarity of 98% with B. subtilis and was designated as B. subtilis based on phylogenetic analyses using 16S rDNA sequences. Generally, most bacteria and their enzymes are destroyed or inactivated in the presence of high concentrations of organic solvents. However, the lipase activity of B. subtilis BCNU 5005 was very stable in the presence of various kinds of solvents (25%, v/v) except chloroform, ethylbenzene and decane. Furthermore, BCNU 5005 was determined to have a degradative ability towards organic solvents. This organic solvent tolerant Bacillus sp. BCNU 5005 could be used as a new potential resource for biotransformation and bioremediation.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.529-532
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• 2001

Korean food waste, one of the abundantly available but environmentally problematic organic wastes in Korea, was utilized as solid-substrate by fungal strain Aspergillus niger ATcC 6275 for the production of enzymemixture containing amylase, cellulase and xylanase. The enzyme mixture can be used as high value-added animal feed. Solid-state fermentation method yielded a 84-fold enhancement in xylanase activity compared with submerged fermentation method. The effect of incubation period, incubation temperature, pH of medium, moisture content, inoculum size and enrichment of the medium with nitrogen and carbon sources were observed for optimal production of these enzymes The optimal amylase activity of 33.10 U/g, cellulase activity of 24.41 U/g, xylanase activity of 328.84 U/g were obtained at 8 days incubation with 50%(w/w) soy bean flake, with incubation temperature of $25^{\circ}C$, pH of 6.38, optimal moisture content of 55% and with inoculum size of $3.8{\times}10^6$spore/g. Enzyme activities were enhanced when ImM $CaSO_4$, 2% Malt extract and 2% galactose were added as mineral, nitrogen and carbon enrichment respectively.

• Journal of Environmental Impact Assessment
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• v.10 no.2
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• pp.85-98
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• 2001

This study was conducted to investigate the geochemical factors governing the distribution of heavy metals(Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in the marine surface sediment samples collected from the Samcheonpo coal-fired power plant. Variations of absolute metal concentrations were related to those in textural and/or carbonate and organic matter content. Most elements, except for Pb, showed generally lower contents compared with the average shale concentration, and the effect of anthropogenic input appeared to be minimal in the sediments. Computations of LF%(labile fraction) and EF(enrichment factor) based on all trace metal data indicated the presence of mineralogical control for Co, Cr, Cu, Ni, and Zn, and anthropogenic contamination for Pb, which needs to be considered in the design of long term monitoring programmes.

• Journal of Wetlands Research
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• v.13 no.2
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• pp.243-263
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• 2011

In order to understand the sedimentary environment of the southern intertidal zone of Shihwa Lake, west coast of Gyeonggi-do, 10 surface and 2 core sediment samples were analysed for grain size, water content, AVS (Acid Volatile Sulfide), TOC (Total Organic Carbon), concentrations of metals (Al, Fe, Mn, Cu, As, Pb, Zn, Ni, Cd, and Cr). The surface sediments are generally poorly sorted (0.60~2.31 ${\phi}$) sandy Silt, slightly gravelly muddy Sand, silty Sand, Sand with mean grain size of 2.95 to 6.00 ${\phi}$. The sediments contain Al (1.54%), Fe (1.75%), Cu (9.1ppm), As (1.1ppm), Pb (18.8 ppm), Ni (11.0 ppm), Cd (0.02 ppm), and Cr (30.1 ppm) on the average. Heavy metals are concentrated less than ERL (Effect Range-Low), verified by NOAA (National Oceanic and Atmospheric Administration). In the core sediments, they are also less than the ERL. Based on the uniform vertical distribution of excess radioactivity of $^{210}Pb$, the core sediments seen to have been actively mixed biologically or rapidly deposited after the construction of Shi-Hwa Seawall. The 'enrichment factor' of metals, normalized to Al, shows that the upper sediments of 35 cm in depth are more polluted. infect was significant in 2 core sediment samples in 35 cm below layer.

• Food Science and Biotechnology
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• v.17 no.3
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• pp.447-456
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• 2008

Limonene, pinene, and isoprene are abundant and ubiquitous volatile organic compounds (VOCs) which are found in various natural products and also produced from various manufacture processes. Limonene and pinene are major components of food additives and household products for enrichment of good flavors and elimination of malodors, and isoprene is a basal motif of monoterpenes such as limonene and pinene. They have shown many beneficial effects such as chemopreventive, chemotherapeutic, and antioxidant activities. Upon certain conditions, however, adverse effects of these compounds on human health have also been reported. Although they do not seem to have acute and severe toxicity to human, they can easily generate secondary organic aerosols (SOAs) when they react with oxygen and/or ozone, which have shown certain toxic effects on experimental animal models as well as on humans. Numerous household and scented products containing limonene, pinene, and isoprene are widely used in these days. However, biological consequences upon exposure to these products are largely unknown. The aim of this review is to summarize and analyze the current understanding on the biological effects of VOCs, in particular limonene, pinene, and isoprene, as well as their SOAs.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.6
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• pp.1014-1025
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• 2014

We measured the concentrations of various geochemical parameters [grain size, ignition loss (IL), chemical oxygen demand (COD), acid volatile sulfide (AVS), and trace metals (Fe, Cu, Cd, Pb, Cr, Mn, As, Zn, and Hg)] in the surface sediments of two intertidal oyster Crassostrea gigas farming areas (Iwon and Mongsan tidal flats) on the Taean Peninsula, Korea, to evaluate the pollution level of organic matter and trace metals in sediment. The intertidal sediments in the study region comprise mostly sand with a mean grain size of 2.5-3.5 Ø. The concentrations of IL, COD, AVS, and trace metals in the sediment of two study regions were either similar or lower in oyster farming areas relative to non-farming areas, apparently due to biological uptake or physical and biological sediment reworking. Based on the results for the pollution evaluation of organic matter and trace metals derived from sediment quality guidelines, enrichment factor, and geoaccumulation index, our results suggest that the sediment in these two intertidal oyster farming regions is not polluted by organic matter and trace metals.