• Korean Journal of Soil Science and Fertilizer
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• v.17 no.3
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• pp.258-264
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• 1984

Pot and field experiments were conducted to find out the effects of lime application on growth and Cd uptake of paddy rice in Cd added and contaminated soils. Lime application to soil-applied Cd could reduce Cd content in brown rice as well as increasing rice yields compared to that of no lime. The optimum requirement of lime to maintain Cd content in brown rice below 0.4 ppm (precaution concentration) were 56,381 and 512kg/10a at 3, 6 and 12 ppm of Cd in soil by pot experiment and 142.7 and 623.9kg/10a at 1.5 and 5.4 ppm of Cd in soil by field trial, respectively. The recommendable soil pH before transplanting to keep the Cd content in brown rice below 0.4 ppm were 5.2, 7.2 and 7.5 at 3, 6 and 12 ppm of Cd in soil, respectively.

• Journal of the Korean GEO-environmental Society
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• v.13 no.1
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• pp.5-13
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• 2012

For the last decade the amount of waste has rapidly been increased in South Korea and many waste landfills have been built according to government guidelines specifying required systems such as landfill liner, leachate collecting facilities, final cover system, etc. This effort has led the recently constructed landfills to be under well managed sanitary condition. In a meanwhile closed waste-landfill sites in the past before the adoption of the government guidelines exits under unsanitary condition. In these cases untreated leachate flew out to the surroundings due to the absence of liner and leachate collecting facilities and caused groundwater and soils to be contaminated. Waste generated odor and gas also brought civil complaints. Because environmental influences bring serious problems nearby sites, it is required to have unsanitary waste-landfills to be appropriately treated and managed. A study to evaluate environmental influence and contamination level of surroundings nearby and on the unsanitary landfills is necessary before the establishment of "Management guide of closed landfill site." This paper presents an environmental evaluation for the closed site, Doil-dong landfill, according to "Closed landfill management regulation" by Ministry of Environment. "D" landfill, located in Pyeongtaek city, has possobility to contaminate surrounding surfacewater and groundwater by leakage of leachate. The in-situ stabilization carried out to build the DMW(deep soil mixing cutoff wall) wall and drainage systems.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.5
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• pp.949-957
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• 2000

This study investigates the remediation of the phenol or PNP(p-Nitrophenol) contaminated soils in a slurry reactor by a pure culture, P-99. The application of a pure culture for the phenol decontamination make the degradation rate three times faster than that of the mixed activated sludge. The destruction of 300 mg/L phenol was completed in 26 hours. As 1 mg of phenol was added, 0.1457 mg of microorganism was grown in the medium. The pure culture could not utilizes PNP, one of the xenobiotics, as a growth substrate. When the bacteria was induced by phenol enrichment medium. PNP could be effectively transformed with cometabolic process. The induction of the bacteria requires 1 mg of phenol for the destruction of 0.027 mg PNP. When PNP concentration in the medium contained phenol and PNP increased. the degradation rate of phenol was decreased. The degradation rate of phenol and PNP in the slurry reactor was about two times faster than in the reactor without slurry because of higher dissolved oxygen supply in the aqueous phase and adsorption on the surface of the soil.

• Korean Journal of Microbiology
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• v.49 no.1
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• pp.83-89
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• 2013

A bacterium, isolated from a vegetable field in a plastic film house and named strain CY6 was capable of biodegrading chlorpyrifos (CP). Based on the phenotypic features and the phylogenetic similarity of 16S rRNA gene sequences, strain CY6 was identified as a Naxibacter sp.. CP was utilized as the sole source of carbon and phosphorus by Naxibacter sp. CY6. We examined the role of this Naxibacter sp. in the degradation of other OP insecticides under liquid cultures. Parathion, methyl parathion, diazinon, cadusafos, and ethoprop could also be degraded by Naxibacter sp. CY6 when they are provided as the sole sources of carbon and phosphorus. Additionally, Naxibacter sp. CY6 ($10^8$ CFU/g) added to soil with CP (100 mg/kg) resulted in a higher degradation rate of approximately 90% than the rate obtained from uninoculated soils. These results highlight the potential of this bacterium to be used in the cleanup of contaminated pesticide soil.

• Journal of Applied Biological Chemistry
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• v.54 no.4
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• pp.252-257
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• 2011

To remove excess nitrate from the agricultural environments, Enterobacter amnigenus GG0461 has been isolated as a bacterial strain having high capability of nitrate uptake activity. This strain was able to remove nitrate more than 3,000 ppm (50 mM) in the Pseudomonas agar F (PAF) medium. Therefore, it could be a candidate strain for a nitrate scavenger in the various contaminated environments, such as agricultural soils, livestock sewage, and industrial wastewater. In order to develop medium for the large-scale production of the strain GG0461, each component of PAF medium was replaced with the corresponding commercial product and the optimal conditions for bacterial growth and nitrate uptake activity were measured. Glycerol was replaced with the commercially available product and the nitrogen source was substituted with commercial tryptone, yeast extract, soybean meal, and fermented fish extract. Bacterial growth and nitrate uptake activity were maximal in the media containing 2% tryptone, followed by yeast extract, soybean meal, and fermented fish extract. The pH of the growth medium containing 2% tryptone was decreased by the bacterial nitrate uptake, suggesting that the nitrate uptake is mediated by a nitrate/proton antiporter. This result shows that the medium containing commercial tryptone was good enough for the physiological activity of the strain GG0461. Each component of PAF medium was successfully replaced with the corresponding commercial product except peptone. In conclusion, the composition of medium for the cultivation of the strain GG0461 was determined as 2% tryptone, 1% glycerol, plus required salts according to the composition of PAF medium.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.9
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• pp.989-996
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• 2007

In this study, abiotic transformation of 1-naphthol(1-NP) via oxidative-coupling reaction and its reaction products were investigated in the presence of Mn oxides. The reaction products were characterized for their relative polarity using solvent extraction experiment and reverse-phase HPLC, and for structure using CCMS and LC/MS, and for absorption characteristics using UV-Vis spectrometry. The reaction products present in aqueous phase were more polar than parent naphthol and comprised of 1,4-naphthoquinon(1,4-NPQ) and oligomers such as dimers and trimers. Hydrophilic component present in water phase after solvent$(CH_2Cl_2)$ extractions was identified as naphthol polymerized products having molecular weight(m/z) ranging from 400 to 2,000, and showed similar UV-Vis. absorption characteristics to that of foil fulvic acid. Transformation of 1,4-NPQ, which is non-reactive to Mn oxide, to the polymerized products via cross-coupling reaction in the presence of 1-NP was also verified. In this experimental conditions(20.5 mg/L, 1-NP, 2.5 g/L $MnO_2$, pH 5), the transformation of 1-NP into the oligomers and polymerized products were about 83% of initial 1-NP concentrations, and more than 30% of the reaction products was estimated to be water insoluble fractions, not extracted by $H_2O$ methanol. Results from this study suggest that Mn oxide-mediated treatment of naphthol contaminated soils can achieve risk reduction through the formation of oligomers md polymer precipitation.

• Korean Journal of Veterinary Research
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• v.26 no.1
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• pp.49-59
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• 1986

This paper deals with the distribution, reservoir and mode of spread of salmonella infection on 7 pig farms in Taegu, Gyeongbuk, Gyeongnam and Chungnam and a slaughter house in Teagu during the period from May 1984 to May 1985. Isolated salmonella were examined for serotypes and biotyping of S. typhimurium. The results obtained were summarised as follows; 1. Of total 7,995 samples from 7 pig farms and a slaughter house, 319 salmonella were isolated from 234 samples (2.9%) and their serovar strains were S. derby 77, S. infantis 41, S. enteritidis 20, S. typhimurium 18, S. bredeney 16, S. london 14, S. paratyphi B 9, S. anatum 8, S. montevideo 8, S. senftenberg 7, S. thompson 6, S. pullorum 4, S. paratyphi A 1 and untypable 70. 2. The incidence rate of diarrhea of piglets, weaned pigs and fattening pigs was 9.8%, 2.3% and 0.5%, respectively whereas the rate by salmonella infection was 4.2%, 1.2% and 11.3%, respectively. 3. The isolation rate of salmonella was higher in summer and autumn. 4. The isolation rate of salmonella varied from 1.1% to 4.5% in 7 pig farms, it was higher in sewages(4.4%), weaned pigs(3.7%), boars(3.7%) and other(3.7%) included soils, manure and wild rats according to samples. Three out of 7 pig farms were contaminated heavily with various serovars of salmonella. 5. The isolation rate of salmonella from pigs slaughtered was 8.1%, it was 13.6% in rectal contents and 1.6% in mensenteric lymph nodes. 6. Eighteen strains of S. typhimurium were classified into 3 different biovars(1, 10 and 10a) by the method of Brandis and were subdivided into 6 different full biovars(1a, 1d, 1dh, 3d, 26i and 26ei) by the method described by Duguid et al. Appearance of different biovars indicated the occurrence of different exotic infection sources on the farms.

• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.2
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• pp.37-44
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• 2001

This study was carried out to evaluate the effects of initial concentration and moisture content on removal of phenol in soil. Texture of soil used was sandy loam. Air was supplied at the rate of $31{\ell}/m^3$(soil)/min. Initial phenol concentrations of contaminated-soils were about 700mg/kg and 1,200mg/kg(as dry weight basis), respectively. Low phenol concentration (about 700mg/kg) was degraded more rapidly than high concentration (about 1,200mg/kg). After phenol concentration of 1,200mg/kg was decreased to about 700mg/kg, its degradation was similar to the case of initial phenol concentration of about 700mg/kg. Phenol degradationrate rate of 15% soil moisture content was higher than that of 20%.

• Journal of the Korean earth science society
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• v.28 no.1
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• pp.112-122
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• 2007

It is known that coal-derived fly ashes have the unique chemical composition and mineralogical characteristics. Since iron oxides in coal fly ash are enriched with heavy metals, the subsurface media including soils, underground water, and sea water are highly likely contaminated with heavy metals when the heavy metals are leached from fly ashes by water-fly ash interactions. The purpose of this study was to investigate how indigenous bacteria affect heavy metal leaching and mineralogy in fly ash slurry during the fly ash-seawater interactions in the ash pond located in Dangjin seashore, Korea. The average pH of ash pond seawater was 8.97 in nature. Geochemical data showed that microbial activity sharply increased after the 7th day of the 60-day course batch experiments. Compared with other samples including autoclaved and natural samples, ${SO_4}^{2-}$ was likely to decrease considerably in the fly ash slurry samples when glucose was added to stimulate the microbial activity. Geochemical data including Eh/pH, alkalinity, and major and trace elements showed that the bacteria not only immobilize metals from the ash pond by facilitating the chemical reaction with Mn, Fe, and Zn but may also be able to play an important role in sequestration of carbon dioxide by carbonate mineral precipitation.

• Journal of Korea Soil Environment Society
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• v.1 no.2
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• pp.91-101
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• 1996

In recent years, phytoremediation, the use of plants to detoxify hydrocarbons, has been a promising new area of research, particularly in situ cleanup of large volumes of slightly contaminated soils. There is increasing need for a mathematical model that can be used as a predictive tool prior to actual field implementation of such a relatively new technique. Although a number of models exist for solute-plant interaction in the vegetated zone of soil, most of them have focused on ionic nutrients and some metals. In this study, we developed a mathematical model for simulation of bioremediation of hydrocarbons in soil, associated with plant root systems. The proposed model includes root interactions with soil-water and hydrocarbons in time and space, as well as advective and dispersive transport in unsaturated soil. The developed model considers gas phase diffusion and liquid-gas mass exchanges. For simulation of temporal and spatial changes in root behavior on soil-water and with hydrocarbons, time-specific distribution of root quantity through soil was incorporated into the simulation model. Hydrocarbon absorption and subsequent uptake into roots with water were simulated with empirical equations. In addition, microbial activity in the rhizosphere, a zone of unique interaction between roots and soil microorganisms, was modeled using a biofilm theory. This mathematical model for understanding and predicting fate and transport of compound in plant-aided remediation will assist effective application of plant-aided remediation to field contamination.