• Journal of the Korean earth science society
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• v.42 no.4
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• pp.412-424
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• 2021

Understanding the distribution of heavy metals in sediment is necessary because labile heavy metals can partition into the water column and bioaccumulate in aquatic organisms. Here we investigated six heavy metals (Co, Cu, Mn, Ni, Pb, and Zn) in sediment cores using a five-step sequential leaching method to examine the occurrence of heavy metals in the sediment. The results showed that all elements, except Mn, are depleted in the exchangeable and carbonate fractions. However, heavy metal concentrations are much higher in the Fe-Mn oxide and organic matter fractions, especially for Cu, indicating enrichment in the organic matter fraction. Furthermore, contamination parameters (contamination factor and geoaccumulation index) indicate that Mn contamination is high, primarily derived from anthropogenic sources, presenting a potential risk to ecosystems in the Nakdong River.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.9
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• pp.604-608
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• 2014

This study investigated influence of dissolved organic nitrogen (DON) in natural organic matter (NOM) on the formation of organic chloramines upon monochloramination. Ratios of dissolved organic carbon (DOC) to DON of the 16 NOM isolates ranged from 7 to 47 mg-C/mg-N. Levels of organic chloramines maxed in 24 hours at $0.16mg-Cl_2/mg-N$ in average. The yields were relatively lower, but decay of organic chloramines were slower than those upon chlorination. Organic chloramines formed upon monochloramination decreased by 56% in average in 120 h. NOM with lower DOC/DON ratios formed more organic chloramines. NOM fractions such as hydrophobic, hydrophilic, transphilic, and colloidal did not significantly impact formation of organic chloramines. As the monochloramine doses increased, more organic chloramines were produced ($R^2=0.91$). Overestimation of disinfection capacity due to the formation of organic chloramines may not be concerns for monochloramine systems since only 6% of monochloramine could be converted to organic chloramines upon monochloramination of NOM.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.E
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• pp.27-40
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• 1998

The solubility characteristics of organic compounds were studied in terms of the extraction efficiency as a function of the polarity of the organic solvent, and the acidity of water in urban aerosol samples collected in University of East Anglia (UEA), Norwich, England. The extraction efficiency of organic compounds were evaluated with respect to the organic carbon, -nitrogen and -hydrogen by means of a wide range of solvent which include polar and nonpolar organic solvents as well as acids and alkaline water. In addition, after being dissolved in aqueous solution, the aqueous chemistry of organic compounds were studied in terms of the organic metal complexes in aerosol, which were studied with oxalic acid, copper, and zinc. The results of this study indicate that solubility characteristics of organic compounds depend on the polarity of the solvents and the acidity of the solvents. In particular, some organic compounds are water soluble, even though they are much smaller than acetone soluble fractions. In the comparison between polar organic solvent extraction and non- polar organic solvent extraction, it can be thought that significant fraction of organic compounds analysed in the aerosol samples, are polar organic compounds because of the higher extraction efficiencies of organic compounds in polar organic solvent extraction than in nonpolar organic solvent extraction. Regarding the study of the oxalic -metal complexes, it can be thought that most oxalic acids are present in the form of oxalic -copper complexes in the aerosols collected at UEA.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.3
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• pp.754-758
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• 2004

To test the cytoprotective effect of sophorae radix (SR) against hydrogen peroxide (H₂O₂)-induced cytotoxicity, we investigated the cell viability using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay in the presence of methylene chloride, n-butanol, ethyl acetate and water soluble fraction of SR water extracts in H9c2 cells. These results were obtained as followed; H₂O₂ decreased the cell viability of H9c2 cells in a dose dependent manner. Cells pretreated with SR water extracts were protected the H₂O₂-induced decrease of viability in H9c2 cells. Among organic solvents fractions of SR water extracts, ethyl acetate soluble fractions of SR protected the decrease of viability induced by H₂O₂ in H9c2 cells. These results suggest that ethyl acetate soluble fractions of SR water extracts is effective in the prevention of H₂O₂-induced cytotoxicity.

• Fisheries and Aquatic Sciences
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• v.21 no.6
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• pp.16.1-16.7
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• 2018

Background: Matrix metalloproteinases (MMPs) are linked with several complications such as metastasis of cancer progression, oxidative stress, and hepatic fibrosis. Brown seaweeds are being extensively studied for their bioactive molecule content against cancer progression. In this context, Sargassum horneri was reported to possess various bioactivities including antiviral, antimicrobial, and anti-inflammatory partly due to its phenolic compound content. Methods: In this study, potential of S. horneri was evaluated through anti-MMP effect in HT1080 fibrosarcoma cells. S. horneri crude extract was fractionated with organic solvents, namely, water ($H_2O$), n-buthanol (n-BuOH), 85% aqueous methanol (85% aq. MeOH), and n-hexane. The non-toxicity of fraction samples (Sargassum horneri solvent-partitioned extracts (SHEs)) was confirmed by cell-viability assay. SHEs were tested for their ability to inhibit MMP enzymatic activity through gelatin digestion evaluation and cell migration assay. Expressions of MMP-2 and MMP-9 and tissue inhibitors of MMP (TIMPs) were evaluated by reverse transcription and Western blotting. Results: All fractions inhibited the enzymatic activities of MMP-2 and MMP-9 according to gelatin zymography. Except $H_2O$ fraction, fractions hindered the cell migration significantly. All tested fractions suppressed both mRNA and protein levels of MMP-2, MMP-9, TIMP-1, and TIMP-2. Conclusion: Overall, current results suggested that S. horneri has potential to be a good source for anti-MMP agents, and further investigations are underway for better understanding of the action mechanism and isolation and elucidation of the bioactive molecules.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.1
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• pp.65-72
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• 2013

This study was carried out to understand the long-term effects of organic waste treatments on the fate of heavy metals in soils originated from the organic wastes and consequent uptake of heavy metals by plant, together with examination of changes in soil properties and plant growth performance. In this study, the soils treated with three different organic wastes (municipal sewage sludge, alcohol fermentation processing sludge, pig manure compost) at three different rates (12.5, 25.0, 50.0 ton $ha^{-1}yr^{-1}$) for 7 years (1994 - 2000) were used. To see the long-term effect, plant growth study and soil examination were conducted twice in 2000 and 2010, respectively. There was no additional treatments of organic wastes for 10 years after the organic waste treatment for 7 years. Compared to plant growth examination conducted in 2000 using radish (Raphanus sativus cv. sodamaltari), it appeared that height, root length and diameter, fresh weight of radish grown in 2010 decreased in the plots treated with municipal sewage sludge and alcohol fermentation processing sludge and that the extent of decrease was higher with increase of sludge application rates. On the other hand, pig compost treatment increased plant height, root length and diameter, fresh weight with increasing application rates. Cu and Pb concentrations in radish root and leaves increased in 2010 compared to those in 2000 while Ni concentrations in root and leaves decreased. Zn concentration was increased only in the soils treated with pig manure compost. Multiple regression analysis among heavy metal species fractions in soils, soil pH, and metal concentrations in radish root and leaves indicated that the metal uptake by radish was governed mainly by the soil pH and subsequent increase of available heavy metal fractions in soils with organic waste treatments.

• Ocean and Polar Research
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• v.24 no.2
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• pp.167-175
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• 2002

Sediment from six piston cores from the East Sea (Sea of Japan) was analyzed for evidence of paleoceanographic changes and paleoclimatic variation. A distinct geochemical boundary is evident in major element concentrations and organic carbon content of most cores near the 10-ka horizon. This distinctive basal Holocene change is interpreted to be largely the result of changing sediment sources, an interpretation supported by TiO_2/Al_2O_3$ ratios. Organic carbon and carbonate contents also differ significantly between the Holocene and glacial intervals. The C/N ratio of organic matter is greater than 10 during the glacial period, but is less than 10 for the Holocene, suggesting that the influx of terrigenous organic matter was more volumetrically important than marine organic matter during glacial times. The chemical index of weathering (CIW) is higher for the Holocene than the glacial interval, and changes markedly at the basal Holocene geochemical boundary. Silt fractions are higher in the glacial interval, suggesting a strong effect of climate on silt particle transportation: terrigenous aluminosilicates and continental organic carbon transport were higher during glacial times than during the Holocene. Differences in sediment composition between the Holocene and glacial period are interpreted to have been climatically induced.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.11
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• pp.769-775
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• 2013

UV-induced transformations in the characteristics of dissolved organic matter (DOM) and the subsequent effects on the disinfection by-product formation potential (DBPFP) were investigated using the mixtures of the two humic substances with different sources, and two different size fractions of Suwannee River fulvic acid (SRFA). 7 day-photodegradation resulted in the decrease of specific ultraviolet absorbance (SUVA) of the mixtures as well as the specific DBPFP. After the irradiation, however, higher specific DBPFP values were consistently observed at the same range of the SUVA values. This suggests that non UV-absorbing components, generated by the UV-irradiation, may contribute to the formation of DBPs. Two different molecular size fractions of SRFA showed dissimilar responses to photodegradation. The behavior was also influenced by the types of the DBPs generated. Higher levels of trihalomethenes (THMs) were formed per organic carbon for the high molecular fraction compared to the low molecular fraction, whereas no differences were found in the formation of haloacetic acids (HAAs) between the two different size fractions. The formation of the two types of DBPs also differed by the irradiation times. Specific formation potential of THMs consistently increased upon the irradiation, whereas HAAs showed the initial increase followed by the decrease in their specific formation potential.

• Korean Chemical Engineering Research
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• v.45 no.5
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• pp.500-505
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• 2007

The objectives of this research were to (1) identify the membrane fouling potential due to different fractions of NOM (2) correlate the physicochemical properties of NOM and membranes with the adsorption of humic substances on membrane (4) find out the effect of membrane physical and chemical washing according to membrane material. The static adsorption test and adsorption test showed that hydrophobic organics adsorbed much more quickly than hydrophilic organics. In case of the effect of membrane properties on the adsorption of organic fractions, the adsorption rate ratio(a) of hydrophobic membrane (0.016, 0.077) was greater than that of hydrophilic membrane (0.010, 0.033) regardless of the kind of organic fractions. This suggests that the UF membrane fouling were occurred mainly by internal pore size decreasing due to adsorption of organic into pore surface for hydrophobic membrane, and by sieving of organics and forming a gel layer on the membrane surface for hydrophilic membrane. In conclusion, the decrease in the pore volume, which was caused by the organic adsorption into the internal pore, was greater with the hydrophobic membrane than with the hydrophilic membrane. In case of the effect of membrane properties on permeate flux, the rate of flux decline for the hydrophobic membrane was significantly greater than that for the hydrophilic membrane.

• Journal of Life Science
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• v.33 no.2
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• pp.138-148
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• 2023

This study compared and analyzed the antioxidant activities of various organic solvent fractions from the leaves and roots of Peucedanum insolens Kitagawa. For this study, the dried leaves and roots of P. insolens Kitagawa were first extracted using 70% ethanol. The extracts were sequentially sub-fractionated in the order of hexane, chloroform, ethyl acetate, n-butanol, and water. The results revealed that the distribution of total phenolic contents by organic solvent fractions showed the same pattern in both the leaves and roots, with the highest in the ethyl acetate fraction (101.1±1.0 mg vs 71.2±3.4 mg of GAE/mg), but the lowest content in the hexane fraction (9.5±0.2 mg vs 7.5±2.1 mg of GAE/mg). The distribution of total flavonoid content in the organic solvent fractions showed the same pattern as that of total phenolic content. The results of DPPH, ABTS, and FRAP assays showed that the leaf and root extracts exhibited free radical scavenging activity in the same pattern, particularly, the ethyl acetate fraction had the highest activity. These results indicate that not only the roots of P. insolens Kitagawa but also the leaves possess potential substances that exhibit strong antioxidant activity. Significant correlations (R=0.903, p<0.0001, DPPH radical; R=0.891, p<0.001, ABTS radical; R=0.745, p<0.05, FRAP radical) between total phenolics and radical scavenging activities, but also significant correlations (R=0.867, p<0.001, DPPH vs. ABTS radicals; R=0.882, p<0.0001, DPPH vs. FRAP radicals; R=0.973, p<0.0001, ABTS vs. FRAP radicals) between radical scavenging activities were found in the organic solvent fractions. Therefore, as in the roots of P. insolens Kitagawa, the leaves possess strong antioxidant capacity and can be used as the main antioxidant material.