• Journal of Life Science
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• v.34 no.8
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• pp.540-547
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• 2024

The continuous use of polymer materials has exacerbated waste and environmental challenges, spurring a growing interest in eco-friendly polymers, especially biodegradable polymers. These polymers are gaining attention for their potential as antimicrobial agents, particularly in fields like food packaging a need further underscored by the recent COVID-19 pandemic. This study focuses on the development of an antibacterial polymer by combining poly-butylene adipate terephthalate (PBAT) with zinc pyrithione (ZnPt). The antibacterial properties were assessed through turbidity analysis, the shaking flask method, and the film adhesion method. The antibacterial activities of the composites with varying ZnPt% (w/w) contents (0, 0.1, 0.3, and 0.5) were evaluated against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Results revealed that even at a low concentration of 0.1% (w/w), the composites demonstrated significant antibacterial activity against both Gram-positive bacteria (S. aureus) and Gram-negative bacteria (E. coli). Composites with ZnPt concentrations of 0.3% (w/w) or higher achieved over 99.999% antibacterial efficacy. Field emission scanning electron microscopy (FE-SEM) analysis of the fracture surfaces of the composites confirmed the uniform distribution of ZnPt particles, ranging from 1-4 ㎛. Further FE-SEM analysis of bacterial suspensions exposed to the composite surfaces showed clear evidence of cell wall destruction in both E. coli and S. aureus. As an antimicrobial biodegradable polymer, PBAT-ZnPt composites show great promise for applications in various sectors, including food packaging.

• Korean Journal of Environmental Agriculture
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• v.24 no.2
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• pp.106-116
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• 2005

This experiment was conducted to investigate available extraction capacity and potential mobility of heavy metal according to the distribution property and contamination level of heavy metals in soils and to suggest a reform measure of soil environment assessment methodology applied with soil quality and the official soil heavy metal test methods in domestic and foreign countries. The soils were collected from the natural forest paddy with long-term application of same type fertilizer, and paddies near metal mine and industrial complex. The post-treatment methods of soil were partial extraction, acid digestion and sequential extraction methods. For the heavy metal contents with different soil properties, it was shown that their natural forest and paddy soil were slightly low and similar to the general paddy soil, while their paddies near metal mine and industrial complex were higher than the standard level of Soil Environment Protection Act. Heavy metal concentrations in the soils with different soil properties had difference between $HNO_3\;and\;HNO_3+HCl$ extractant by US-EPA 3051a method. There were highly significant positive relationships in both two methods. It was appeared that the higher extractable concentration ratio with 0.1N-HCl to total heavy metal content with $HNO_3+HCl$ extractant the greater total heavy metal content. There were highly significant positive correlationship between total heavy metal content and extractable content with 0.1N-HCl. For extractable capacity of soil extractable solution compared to the total heavy metal content it was appeared that it extractable method with 0.1N-HCl was higher than those with EDTA and DTPA. In extractable ratio with 0.1N-HCl in the contaminated paddy soils near mine and industrial complex, it was shown that the lower soil pH, the higher total heavy metal content. The order of a potential mobility coefficient by distribution of heavy metal content with ie different typies in the soil was Cd>Ni>Zn>Cu>Pb. It could be known that contamination characteristics of heavy metals with different types of soils were affected by different heavy metal components, contamination degree and soil chemical properties, and heavy metal concentration with different extractable methods had great variations with adjacent environment. To be compared with assessment methodology of soil environment impact at domestic and foreign countries with our results, it might be considered that there was necessary to make a single analysis method based on total heavy metal content with environmental overloading concept because of various analysis methods for total heavy metal content and present analysis method with great variation according to soil environment. In spite of showing higher concentration of heavy metal with acidic digestion than the extractable method, it might be considered that there is need to be adjusted the national standard of soil heavy metal contamination.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.1
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• pp.33-41
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• 2001

Enormous volumes of mining wastes from the abandoned and closed mines are disposed without a proper treatment in the upper Okdong River basin at Southeastern part of Kangwon Province. Erosion of these wastes contaminates soil, surface water, and sediments with heavy metals. Objectives of this research were to fractionate heavy metals in the mine tailing stored in the Sangdong Tungsten tailing dams and to assess the potential pollution index of each metal fraction. Tailing samples were collected from tailing dams at different depth and analyzed for physical and chemical properties. pH of tailings ranged from 7.3 to 7.9. Contents of total N and organic matter were in the ranges of 3.2~5.5%, and 1.3~9.1%, respectively. Heavy metals in the tailings were higher in the newly constructed tailing dam than those in the old dam. Total concentrations of metals in the tailings were in the orders of Zn > Cu > Pb > Ni > Cd, exceeded the corrective action level of the Soil Environment Conservation Law and higher than the natural abundance levels reported from uncontaminated soils. Relative distribution of heavy metal fractions was residual > organic > reducible > carbonate > adsorbed, reversing the degree of metal bioavailability. Mobile fractions of metals were relatively small compared to the total concentrations. Distribution of metals in the tailing dam profiles was metal specific. Concentrations of Cu at the surface of tailing dams were higher than those at the bottom. Pollution index (PI) values of each fraction of metals were ranged from 4.27 to 8.51 based on total concentrations. PI values of mobile fractions were lower than those of immobile fractions. Results on metal fractions and PI values of the tailing samples indicate that tailing samples were contaminated with heavy metals and had potential to cause a detrimental effects on soil and water environment in the lower part of the stream. A prompt countermeasure to prevent surface of tailings in the dams from water and wind erosions is urgently needed.

• Economic and Environmental Geology
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• v.55 no.6
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• pp.727-736
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• 2022

Ice wedges are subsurface ice mass structures that formed mainly by freezing precipitation with airborne dust and surrounding soil particles flowed through the active layer into the cracks growing by repeating thermal contractions in the deeper permafrost layer over time. These ice masses characteristically contain high concentrations of solutes and solids. Because of their unique properties and distribution, the possibility of harnessing ice wedges as an alternative archive for reconstructing paleoclimate and paleoenvironment has been recently suggested despite limited studies. It is imperative to preserve the physicochemical properties of the ice wedge (e.g., solute concentration, mineral particles) without any potential alteration to use it as a proxy for reconstructing the paleo-information. Thawing the ice wedge samples is prerequisite for the assessment of their physicochemical properties, during which the paleo-information could be unintentionally altered by any methodological artifact. This study examined the effect of thawing conditions and procedures on the physicochemical properties of solutes and solid particles in ice wedge samples collected from Cyuie, East Siberia. Four different thawing conditions with varying temperatures (4 and 23℃) and oxygen exposures (oxic and anoxic) for the ice wedge sample treatment were examined. Ice wedge samples thawed at 4℃ under anoxic conditions, wherein biological activity and oxidation were kept to a minimum, were set as the standard thawing conditions to which the effects of temperature and oxygen were compared. The results indicate that temperature and oxygen exposure have negligible effects on the physicochemical characteristics of the solid particles. However, the chemical features of the solution (e.g., pH, electric conductivity, alkalinity, and concentration of major cations and trace elements) at 4℃ under oxic conditions were considerably altered, compared to those measured under the standard thawing conditions. This study shows that the thawing condition of ice wedge samples can affect their chemical features and thereby the geochemical information therein for the reconstruction of the paleoclimate and/or paleoenvironment.

• Economic and Environmental Geology
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• v.33 no.2
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• pp.91-100
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• 2000

It has been more than ten years since Dukun mine was abandoned. Tailings of waste deposits and slime dumps in the abandoned Dukum mine have been left to be deserted for fifty years. The results of fifty years of neglecting are nothing short of major environmental problems. Slime dumps have been exposed to air and water in the mine over ten years and then soil profile has been formed well. Soil in the upper layer (A horizon) is the light gray color due to the leaching of cations. Soil in the lower layer (A2 horizon, 0.2∼0.3m)is tinted with reddish brown and yellowish brown color due to the development of iron oxides and iron hydroxides. Soil in the lower part of B horizon of (1.0∼3.0m) with the growth of copper and zinc oxides exposes to the bluish green, light blue, and dark gray. Ranging from 3m to 8m in depth, 85 samples were taken from 22 sampling sites with 50m intervals located on the slime dump area with hand auger and trench (open cut). As tailings was distributed, heavy metal elements extracted by the process of surface water and ground water move and disperse in to the hydrosphere. Waste dumps were distributed in and around the mine and water draining from those dumps be a potential source of contamination. Soils, thus, can be dispersed into downslope and downstream through wind and water by clastic movement. These materials may be deposited in another horizon if the water is withdrawn, or if the materials are precipitated as a result of differences in pH, or other conditions in deeper horizons. These were primarily associated with acid mine drainage. The characteristics and rate of release of acid mine drainage are influenced by various chemical and biological reactions at the source of acid generations. Prolonged extration of heavy metal elements has a detrimental effect on the agricultural land and residental area. Twenty soil samples were collected from the agricultural land in the area (0∼30 cm). Seventeen samples were also taken from the sediment in the stream running alongside the dumps. The dispersion patterns of heavy metal elements are as follows: The content of As ranged 2∼6 ppm in a horizon, 20∼125 ppm in B horizon with large amount of clay mineral is concentrated and the content of Cd ranged 1∼2 ppm in A horizon, 4∼22 ppm in B horizon. Like Cd, the content of As, Cu, Zn, Pb in B horizon is higher than that in A horizon (approximately 5∼100 times). When soil formation proceeds in stages, it is necessary to investicate the B horizon with the concentration of heavy metal and preventive measures will have to established.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.4
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• pp.555-569
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• 2004

Size -segregated measurements of aerosol composition using 8-stage DRUM impactor are used to determine the transport of natural and anthropogenic aerosols at Gosan site from 29 March to 30 May in 2002. Separation of ambient aerosols by DRUM impactor offers many Advantages over other standard filtration techniques. Some of the most important advantages are the ability to segregate into details by particle tire, to better preserve chemical integrity since the air stream doesn＇t pars through the deposit, to collect samples as a function of time, and to have a wide variety of impaction surfaces available to match analytical needs. Although the transport of Yellow sand is a well-known phenomenon in springtime, the result of measurement shows that not only soil dust but also anthropogenic aerosols, including sulfur, enriched trace metals such as Pb, Ni, Zn. Cu, Cr, As, Se, Br, are transported to Gosan in springtime. This study combines the size- and time-resolved aerosol composition measurements with isentropic, backward air-mass trajectories in order to identify some potential source regions of anthropogenic aerosols. As a result, during the NYS period, the average concentration of PM$_{10}$ was 46$\mu\textrm{g}$/㎥, Si, Al. S, Fe, Cl, K, Ca were higher than 1,000 ng/㎥ and Ti was about 100 ng/㎥. The concentrations of Zn, Mn, Cu. Pb, Br, Rb, V, Cr, Ni. At, Se ranged between 1 and 70 ng/㎥. More than 50% typical soil elements, tuck as Al, Si, Fe, Cd. Ti, Cr, Cu, Br. were distributed in a coarse particle range(5.0-12${\mu}{\textrm}{m}$). In other hand, anthropogenic pollutants, luck as S, N, Vi, were mainly distributed in a fine particle range (0.09-0.56${\mu}{\textrm}{m}$). During the YS period, PM$_{10}$ increased about 8 times than NYS period, and main soil elements, such as Al, Si, S, K, V, Mn, Fe also doubled in coarse particle range (1.15-12${\mu}{\textrm}{m}$). But Zn, As, Pb, Cu and Se, which distributed in the time aerosols (0.09-0.56${\mu}{\textrm}{m}$), were on the same level with or decreased than NYS period. Finally. except the YS Period, coarse particles (2.5-12${\mu}{\textrm}{m}$) are inferred to be influenced by soil, coal combustion, waste incineration, ferrous and nonferrous sources through similar pathways with Yellow Sand. But fine particles have different sources, such as coal combustion, gasoline vehicle, biomass burning, oil or coal combustion, nonferrous and ferrous metal sources, which are transported from China, Korea peninsula and local sources.ces.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.1
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• pp.61-68
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• 2010

In this study, we investigated the concentrations of volatile organic compounds (VOCs) in Shiwha area and compared the characteristics of both industrial area and residential area. The passive samplers were set 6 times each for a month in 21 locations at industrial and residential area to obtain 6 VOCs including benzene, trichlorobenzene, toluene, ethyl benzene, xylene and stylene. Above all, toluene was the most abundant VOCs in the ambient air both in industrial and residential area. Average TVOC concentration of industrial area was 1.86 times higher than that of residential area, and it was greatly reduced in winter compared with summer. Furthermore, the average BTEX concentrations showed that all concentrations of industrial area were 1.94~5.39 times higher than those of residential area except benzene which were similar to each other. In winter, the concentration of ethyl benzene and xylene were significantly decreased by comparing with summer: but benzene concentrations were increased. Also, BTEX relative ratio was as follows: toluene>benzene>ethylbenzene>xylene. Correlation coefficients among VOCs were confirmed that VOCs in ambient air of industrial area were generally more related to each other than that of residential area. On the whole, the concentrations of VOCs in industrial area were higher, and it seems to be potential that industrial area affects the distribution of VOCs to residential area.

• Tuberculosis and Respiratory Diseases
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• v.80 no.3
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• pp.247-254
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• 2017

Background: Airway epithelial cells are the first line of defense, against pathogens and environmental pollutants, in the lungs. Cellular stress by cadmium (Cd), resulting in airway inflammation, is assumed to be directly involved in tissue injury, linked to the development of lung cancer, and chronic obstructive pulmonary disease (COPD). We had earlier shown that ACN9 (chromosome 7q21), is a potential candidate gene for COPD, and identified significant interaction with smoking, based on genetic studies. However, the role of ACN9 in the inflammatory response, in the airway cells, has not yet been reported. Methods: We first checked the anatomical distribution of ACN9 in lung tissues, using mRNA in situ hybridization, and immunohistochemistry. Gene expression profiling in bronchial epithelial cells (BEAS-2B), was performed, after silencing ACN9. We further tested the roles of ACN9, in the intracellular mechanism, leading to Cd-induced production, of proinflammatory cytokines in BEAS-2B. Results: ACN9 was localized in lymphoid, and epithelial cells, of human lung tissues. ACN9 silencing, led to differential expression of 216 genes. Pathways of sensory perception to chemical stimuli, and cell surface receptor-linked signal transduction, were significantly enriched. ACN9 silencing, further increased the expression of proinflammatory cytokines, in BEAS-2B after Cd exposure. Conclusion: Our findings suggest, that ACN9 may have a role, in the inflammatory response in the airway.

• Journal of Environmental Health Sciences
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• v.42 no.1
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• pp.10-18
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• 2016

Objectives: Microcystin (MC) produced during cyanobacterial blooms is a worldwide problem presenting a serious health threats to humans and ecosystems. During July through October of 2013, the Ilwol Reservoir experienced a high biomass of phytoplankton (maximum $211.7mg/m^3$ of Chlorophyll-a) containing the toxigenic cyanobacterium Oscillatoria sp. The aim of this study is to analyze MC concentration in the reservoir water, as well as in representative fish species (Carassius cuvieri, Carassius auratus, Channa argus). We also evaluated the human health risk of exposure to MCs accumulated in the fish. Methods: Concentrations of MCs in the water and fish samples were analyzed by liquid chromatography with a triple quadrupole tandem mass spectrometer (LC/MS/MS) and enzyme-linked immunosorbent assay (ELISA). Results: The total levels of four MC variants, including MC-LR, MC-RR, MC-YR and MC-LA were below the WHO drinking water guideline limit (1 ug MC-LR per liter) both for the dissolved and particulate fraction present in the water samples. The mean MC concentrations in the livers of all species were significantly higher than in the gills (p < 0.01) and muscles (p < 0.05). The values of estimated daily intake of MCs in muscles, the edible part of the fish, would be only $0.005-0.015{\mu}g/kg{\cdot}day$, much lower than WHO's provisional tolerable daily intake of $0.04{\mu}g/kg{\cdot}day$. Conclusion: This study suggests that, owing to the spatial distribution or temporal variation of MC, there is a need for careful monitoring of cyanotoxin in reservoir water and aquatic animals to protect public health.

• Journal of Wetlands Research
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• v.22 no.2
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• pp.153-160
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• 2020

Most studies defined microplastic (MP) as plastic particles less than 5 mm. The ubiquity of MP is raising awareness due to its potential risk to humans and the environment. MP can cause harmful effects to humans and living organisms. This paper review aimed to provide a better understanding of the sources, pathways, and impacts of MP in the environment. MP can be classified as primary and secondary in nature. Moreover, microplastic can also be classified as based on its physical and chemical characteristics. Stormwater and wastewater are important pathways of introducing MP in large water bodies. As compared to stormwater, the concentrations of MP in wastewater were relatively lower since wastewater treatment processes can contribute to the removal of MP. In terms of polymer distribution, wastewater contains a wider array of polymer varieties than stormwater runoff. The most common types of polymer found in wastewater and stormwater runoff were polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), polyethylene (PE) and polyethylene terephthalate (PET). The continuous discharge and the increasing number of MP in the environment can pose greater hazards and harmful effects on humans and other living organisms. Despite the growing number of publications in relation to MP, further studies are needed to define concrete regulations and management strategies for mitigating the detrimental effects of MP in the environment.