• Journal of Korean Society on Water Environment
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• v.32 no.5
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• pp.419-432
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• 2016

The aim of this study is to assess the influence of effluent discharge from a sewage treatment plant by evaluating oxidative stress and histopathological alterations in freshwater crucian carp Carassius auratus collected from the Eungcheon stream, located in Korea. Catalase activity in the gills, liver, and kidneys of C. auratus was collected from mixing zones; the downstream site was notably higher of fish than that of the upstream site. In addition, the activity of glutathione-S-transferase in the gills and liver was significantly higher in samples from the mixing zone than in those from the upstream site (p < 0.05). In addition, significantly elevated lipid peroxidation levels were observed in fish livers sampled from the mixing zone than in those from the upstream site (p < 0.05). Significant histopathological alternations were also observed in C. auratus, with the order of magnitude changes being liver > kidney > gills. These findings suggest that the liver is most affected by effluent discharge. The degree of tissue changes (DTC) indicate that the highest level occurred in samples from the mixing zone (30.98 ± 5.40) followed by those from the downstream site (19.28 ± 4.31) and was the lowest in samples from the upstream site (4.83 ± 2.67). These findings indicate that fish collected from the mixing zone are most affected by effluent discharge and both oxidative stress and histopathological indices are useful tools for monitoring contaminated rivers and streams.

• Journal of Environmental Impact Assessment
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• v.8 no.2
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• pp.31-44
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• 1999

Atmospheric dry deposition flux and ambient particle mass size distribution were measured to evaluate the impact of atmospheric deposition around the Nanjido landfill sites. Wind direction affects greatly on the variation of mass flux and mass size distribution and made two times higher when the wind was blown from the road side. The effect of Nanjido landfill on the mass size distribution was significant comparing to simultaneously measured mass size distribution at the other sampling site. The results showed that the particle diameter bigger than $10{\mu}m$ explained the majority of atmospheric dry deposition flux. A survey was also carried out to investigate the contamination of soils in a completed Nanjido landfill. The chemical properties of the soil analyzed in the present study include pH, oxidation-reduction potential (ORP), anion and cation concentration, total organic carbon(TOC), and some-metal elements concentrations were analyzed. Microbial activity in the soils was also evaluated by measuring dehydrogenase activities. TOC in the soil contaminated with leachate was $467.0{\mu}g/g-dry$ soil, and the TOC in the soil, where Nanjido landfill gases were emitted from, was $675{\mu}g/g-dry$ soil. The highest microbial activity of $968.0{\sim}2147{\mu}g-TPF/g-dry$ soil day was found in the soil spouting Nanjido landfill gases. Compared with those in the uncontaminated soil, the concentrations of Cr, Cu and Ph in the contaminated soil were higher.

• Journal of Biosystems Engineering
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• v.34 no.5
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• pp.377-381
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• 2009

Excessive presence of heavy metals in environment may contaminate plants and fruits grown in that area. Rapid on-site monitoring of heavy metals can provide useful information to efficiently characterize heavy metal-contaminated sites and minimize the exposure of the contaminated food crops to humans. This study reports on the evaluation of a bismuth-coated glassy carbon electrode for simultaneous determination of cadmium (Cd) and lead (Pb) in a NIST-SRM 1568a rice flour by anodic stripping voltammetry (ASV). The use of a supporting electrolyte 0.1 M $HNO_3$ at a dilution ratio (sample pretreated with acid digestion in a microwave oven: supporting electrolyte) of 1:1 provided well-defined, sharp and separate peaks for Cd and Pb ions, thereby resulting in strongly linear relationships between Cd and Pb concentrations and peak currents measured with the electrode ($R^2\;=\;0.97$, 0.99 for Cd and Pb, respectively). The validation test results for spiked standard solutions with different concentrations of Cd and Pb gave acceptable predictability for both spiked Cd and Pb ions with mean prediction errors of 6 to 30%. However, the applicability of the electrode to the real rice flour sample was limited by the fact that Cd concentrations spiked in the rice flour sample were overly estimated with relatively high variations even though Pb ion could be quantitatively measured with the electrode.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.77-82
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• 2004

Quantifying rates of microbial processes under subsurface conditions is difficult, and is most commonly approximated by laboratory studies using aquifer materials. In this study a single-well, 'push-pull' test method is adapted for the in situ determination of denitrification rates in groundwater aquifers. The rates of stepwise reduction of nitrate to nitrite, nitrous oxide, and molecular nitrogen were determined by performing a series of push-pull tests at an experimental well field of Korea University. A single Transport Test, one Biostimulation Test, and four Activity Tests were conducted for this study. Transport tests are conducted to evaluate the mobility of solutes used in subsequent tests. These included bromide (a conservative tracer), fumarate (a carbon and/or source), and nitrate (an electron acceptor). At this site, extraction phase breakthrough curves for all solutes were similar, indicating apparent conservative transport of the solutes prior to biostimulation. Biostimulation tests were conducted to stimulate the activity of indigenous heterotrophic denitrifyinc microorganisms. Biostimulation was detected by the simultaneous production of carbon dioxide and nitrite after each injection. Activity tests were conducted to quantify rates of nitrate, nitrite, and nitrous oxide reduction. Estimated zero-order degradation rates decreased in the order nitrate '||'&'||'gt; nitrite '||'&'||'gt; nitrous oxide. The series of push-pull tests developed and field tested in this study should prove useful for conducting rapid, low-cost feasibi1ity assessments for in situ denitrification in nitrate-contaminated aquifers.

• Journal of Korea Soil Environment Society
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• v.4 no.3
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• pp.25-33
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• 1999

The recent emergence of biofiltration as a cost effective waste-gas control technology has stimulated in European countries and the USA. Biofiltration of soil vapor extraction off-gas from gasoline contaminated site was simulated in lab-scale in this study. A filling material used was a compost. This study was conducted to evaluate biofiltration characteristics of the compost material for gasoline off-gas. TPH elimination capacity at the gas loading rate of about 50g/$\textrm{m}^3$((filling material)/hr was circa 40g/$\textrm{m}^3$((filling material)/hr. Removal rate of xylene was the highest among BTEX. while it was the lowest in case of bezene. The maximum elimination capacity of the compost was about 1.5g/$\textrm{m}^3$((filling material)/hr for benzene. More than 95% of trimethylbenzene and naphtalene were removed below the loading rate of 0.7g/㎥(filling material)/hr. About 80% of total TPH and BTEX were removed by biodegradation.

• Journal of Soil and Groundwater Environment
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• v.25 no.1
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• pp.25-36
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• 2020

In a redox transition zone, geochemical reactions are facilitated by active bacteria that mediate reactions involving electrons, and arsenic (As) and iron (Fe) cycles are the major electron transfer reactions occurring at such a site. In this study, the effect of repetitive redox changes on soil bacterial community in As-contaminated soil was investigated. The results revealed that bacterial community changed actively in response to redox changes, and bacterial diversity gradually decreased as the cycle repeated. Proportion of strict aerobes and anaerobes decreased, while microaerophilic species such as Azospirillum oryzae group became the predominant species, accounting for 72.7% of the total counts after four weeks of incubation. Bacterial species capable of reducing Fe or As (e.g., Clostridium, Desulfitobacterium) belonging to diverse phylogenetic groups were detected. Indices representing richness (i.e., Chao 1) and phylogenetic diversity decreased from 1,868 and 1,926 to 848 and 1,121, respectively. Principle component analysis suggests that repetitive redox fluctuation, rather than oxic or anoxic status itself, is an important factor in determining the change of soil bacterial community, which in turn affects the cycling of As and Fe in redox transition zones.

• Korean Journal of Environmental Agriculture
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• v.28 no.4
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• pp.340-346
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• 2009

Chromated copper arsenate (CCA) is a chemical wood preservative that has been intensively used to protect wood from decay during the last few decades. CCA is widely used to build structures such as decks, fences, playgrounds and boardwalks. However, structures constructed of CCA-treated wood have caused adverse environmental effects due to leaching of Cr, Cu and As into surrounding soils. This research was conducted to monitor the vertical and horizontal distribution of Cr, Cu and As in soils adjacent to CCA-treated wood structures in Korea. Two structures constructed with CCA-treated wood were selected at Hongcheon and Chuncheon in Gangwon Province, South Korea. Eleven soil profile samples were collected at depths of 0 to 80 cm at each site, while 12 surface soil samples were collected at distances of 0 to 200 cm from each structure. The soil chemical properties, soil particle size distribution and total metal concentrations were then determined. The results revealed that soils near CCA-treated wood structures were generally contaminated with Cr, Cu and As when compared to the background concentration of each metal. In addition, the concentrations of Cr, Cu and As in soils decreased as the vertical and horizontal distance from the structure increased. Further studies should be conducted to evaluate the mobility and distribution of these metals in the environment as well as to develop novel technologies for remediation of CCA contaminated soils.

• Journal of the Korea Organic Resources Recycling Association
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• v.14 no.3
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• pp.148-156
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• 2006

Potential hydrocarbon degrading bacteria were screened from the site artificially polluted with 20,000 ppm of diesel. Among the isolates, two strains, SJD2 and SJD4, showed higher activities to degrade diesel on the Bushnell-Hass broth medium containing 2% of diesel. 16S rDNA sequence analysis revealed that SJD2 and SJD4 were Bacillus fusifomis and B. cereus, respectively. Both strains were found to grow in a wide range of temperature between $20^{\circ}C-55^{\circ}C$, with the best at $30^{\circ}C-37^{\circ}C$. This is the first report, as far as we know, that B. fusifomis is capable of degrading diesel. We hope that a new isolate, B. fusifomis, will efficiently conduct bioremediation at the contaminated sites with petroleum hydrocarbons.

• Journal of Microbiology and Biotechnology
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• v.15 no.5
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• pp.952-964
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• 2005

The diesel-degrading activities of biofilms sampled from petroleum-contaminated groundwaters in urban subway drainage systems were examined in liquid cultures, and the microbial populations of the biofilms were characterized by denaturing gel gradient electrophoresis (DGGE) and 16S rDNA sequence analysis. Biofilm samples derived from two sites (19 K and 20 K) at subway Station N and Station I could degrade around $80\%$ of applied diesel within 20 and 40 days, respectively, at $15^{\circ}C$, and these results were strongly correlated with the growth patterns of the biofilms. The closest phylogenetic neighbor of a dominant component in the 19 K biofilm was Thiothrix fructosivorans strain Q ($100\%$ similarity). Four dominant strains in the 20 K biofilm were closely related to Thiothrix fructosivorans strain Q ($100\%$ similarity), Thiothrix sp. CC-5 ($100\%$ similarity), Sphaerotilus sp. IF14 ($99\%$ similarity), and Cytophaga-Flexibacter-Bacterioides (CFB) group bacterium RW262 ($98\%$ similarity). Three dominant members in the Station I biofilms were very similar to uncultured Cytophagales clone CRE-PA82 ($91\%$ similarity), Pseudomonas sp. WDL5 ($97\%$ similarity), and uncultured CFB group bacterium LCK-64 ($94\%$ similarity). The microbial components of the biofilms differed depending on the sampling site. This is the first report on the isolation of clones highly similar to Thiothrix fructosivorans and Thiothrix sp. from biofilms in petroleum-polluted groundwaters, and the first evidence that these organisms may play major roles in petroleum degradation and/or biofilm-development.

• Journal of Soil and Groundwater Environment
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• v.16 no.5
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• pp.1-8
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• 2011

This study was performed to evaluate the remediation efficiency by Helianthus annuus, Brassica juncea and Brassica campestris on the soil contaminated with nickel, zinc and lead, respectively. The growth rates fell down under 60% in the condition of over 700 mg/kg of zinc for Brassica campestris, 300 mg/kg of lead for Helianthus annuus, and 150 mg/kg of nickel for Brassica juncea on the basis of heavy metal concentration in the soil, because of its toxicity. Also, the hyperaccumulators showed the maximum heavy metal contents in their biomass after 90 days of cultivation. The accumulated heavy metal content per kilogram of hyperaccumulator was 0.65 mg of nickel in Brassica juncea, 0.14 mg of zinc in Brassica campestris, and 0.06 mg of lead in Helianthus annuus, respectively. Additionally, 73.2% of nickel accumulated in Brassica juncea and 95.1% of zinc accumulated in Brassica campestris were concentrated in the upper site of crop like stem and leaves. However, in the case of Helianthus annuus, 83.7% of lead was accumulated in the root.