• Journal of the Korean Geotechnical Society
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• v.16 no.4
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• pp.107-116
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• 2000

In this study, the permeability reduction in the soil-filter systems due to clogging phenomenon was evaluated. An extensive research program was performed using two typical weathered residual soils which were sampled at Shinnae-dong and Poi-dong area in Seoul. Two separate simulation tests with weathered residual soil were performed: one was the filtration test(cross-plane flow test); and the other was the drainage material in the field. The compatibility of the sol-filter system was investigated with emphasis on the clogging phenomenon. The hydraulic behaviour of the soil-filter system was evaluated by changing several testing conditions. Also, experimental results of the permeability reduction are compared with the results obtained from the theoretical model which can monitor the spatial variation of the permeability with time.

• Toxicological Research
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• v.24 no.3
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• pp.207-212
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• 2008

Pesticide residues play several key roles as environmental and food pollutants and it is crucial to develop a method for the rapid determination of pesticide residues in environments. In this study, a simple, effective, and sensitive method has been developed for the quantitative analysis of methoxyfenozide in water and soil when kept under laboratory conditions. The content of methoxyfenozide in water and soil was analyzed by first purifying the compound through liquid-liquid extraction and partitioning followed by florisil gel filtration. Upon the completion of the purification step the residual levels were monitored through high performance liquid chromatography(HPLC) using a UV absorbance detector. The average recoveries of methoxyfenozide from three replicates spiked at two different concentrations and were ranged from 83.5% to 110.3% and from 98.1% to 102.8% in water and soil, respectively. The limits of detection(LODs) and limits of quantitation(LOQs) were 0.004 vs. 0.012 ppm and 0.008 vs. 0.024 ppm, respectively. The method was successfully applied to evaluate the behavioral fate of a 21% wettable powder(WP) methoxyfenozide throughout the course of 14 days. A first-order model was found to accurately fit the dissipation of methoxyfenozide in water with and a $DT_{50}$ value of 3.03 days was calculated from the fit. This result indicates that methoxyfenozide dissipates rapidly and does not accumulate in water.

• 한국균학회소식:학술대회논문집
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• 2015.05a
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• pp.29-29
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• 2015

Clubroot disease is caused by the soil-born obligate plant pathogen Plasmodiophora brassicae. This pathogen can infect all cruciferous vegetables and oil crops, including Brassica rapa, B. oleracea, B. napus, and other Brassica species. Clubroot disease is now considered to be a major problem in Chinese cabbage production in China, Korea, and Japan. We collected several hundreds of P. brassicae infected galls from Korea, and isolated the single spore from the collection. For establishment of novel isolation, and mass-propagation methods for singe spore isolates of P. brassicae pathogen, we developed new filtration method using both cellulose nitrate filter and syringe filter. Accurate detection of P. brassicae pathogen in the field was done by using real-time PCR in the potential infested soil. When we tested the different pathogenicity on commercial Chinese cabbage varieties, P. brassicae from collected galls showed various morphological patterns about clubroot symptom on roots. To date, 8 CR loci have been identified in the B. rapa genome using the quantitative trait loci (QTL) mapping approach, with different resistant sources and isolates. We are trying to develop the molecular marker systems for detect all 8 CR resistant genes. Especially for the study on the interaction between pathogens and CR loci which are not well understood until now, genome wide association studies are doing using the sequenced inbred lines of Chinese cabbage to detect the novel CR genes.

• Journal of Soil and Groundwater Environment
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• v.17 no.6
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• pp.1-8
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• 2012

This study is to suggest a few efficient ways of rainwater utilization, through monitoring and analyzing 143 rainwater storage systems and 110 artificial recharge systems, which are installed in the recommended facilities by law, among the rainwater harvesting systems in Jeju Island. In the case that catchment facilities are damaged, rainwater could be contaminated by leaves and debris so that the rates of rainwater usages come to be lower. It is possible that contaminated rainwater could contaminate artificial recharge wells or rainwater discharging out of the rainwater harvesting system could result in flood and damage for the downgradient area. For maintaining high quality of rainwater and increasing rainwater utilization rate, it is necessary to install screening facilities and purification plant functioning precipitation and filtration. Also, in order to efficiently preclude the overflowing rainwater exceeding storage capacity, it is recommended to associate rainwater storage tanks with artificial recharge well or infiltration trench facilities.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.451-454
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• 2004

The study aims to assess the quality of bank filtrate in relation to streamflow and physico-chemical properties of the stream. Turbidity, pH, temperature and dissolved oxygen (DO) of Nakdong River and riverbank filtrate were statistically analyzed. The physico-chemical properties of riverbank filtrate were measured from irregularly different seven pumping wells every day. Autocorrelation analyses were conducted to the qualities of stream water and bank filtrated water. Temperature, pH and DO of streamflow shows strong linearity and long memory effect, indicating the effect of seasonal air temperature and rainy season. Temperature of riverbank filtrate shows weak linearity and weak memory, indicating differently from the trend of stream temperature. Turbidity of steramflow shows strong linearity and long memory effect, while turbidity of riverbank filtrate indicates weak linearity and weak memory. Cross-correlation analysis shows low relation between turbidity, pH, temperature and DO of riverbank filtrate and those of streamflow. Turbidity of streamflow was largely affected by the streamflow rate, showing a similar trend with autocorrelation function of streamflow rate. The turbidity of riverbank filtrate has a lag time of 25 hours. This indicates that turbidity of streamflow in a dry season has very low effect on the turbidity of riverbank filtrate, and a high turbidity of the stream in a rainy season has a fairly low effect on the turbidity of riverbank filtrate.

• Microbiology and Biotechnology Letters
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• v.20 no.4
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• pp.401-408
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• 1992

The extracellular cholesterol oxidase produced from a soil microorganism HSL613 was purified and partially characterized. Through a series of purification procedures including concentration with CH2 concentrator, DEAE-cellulose column chromatography and gel filtration on Superose12, the purified enzyme was shown to have a specific activity of 108 units/mg protein giving 30.8-fold purification and final yield of 66%. The molecular weight of the enzyme was estimated to be 59,500 daltons by SDS-PAGE. The optimum temperature and pH for this enzyme were $50^{\circ}C$ and 6.0, respectively. The activity of the purified cholesterol oxidase was inhibited by $Ag^{2+}$, $Hg^{2+}$ and SDS.

• Korean Journal of Environmental Agriculture
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• v.17 no.4
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• pp.329-334
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• 1998

This study was conducted in order to investigate removal rate of organic matter, nitrogen and phosphorus to reduce environmental polluation with treatment to attach combined septic tank to 3 stage soil filter after mixing anaerobic treated water of livestock wastewater and low concentrated wastewater generated in farm house. Because anaerobic filter bed was packed in combined septic tank and a microorganism was accumulated in combined septic tank with increasing hydraulic retention time(HRT), if HRT $4{\sim}12day$, CODcr was removed $63.4{\sim}84.0%$. Also, $NH_4\;^+-N$ and $PO_4\;^{3-}-P$ were removed $3.9{\sim}5.4%$ and $18.3{\sim}29.0%$, respectively. In being re-treated by 3 stage soil filter, although hydraulic loading rate was gradually increased, CODcr, $NH_4\;^+-N$ and $PO_4\;^{3-}-P$ were removed above 90% due to filtration, adsorption, ion exchange, and action of soil microorganism. Generally, the attached treatment of combined septic tank and 3 stage soil filter did suitably treat livestock wastewater to water standard of discharge applied from '96 year, in view of decreasing pollution loading amount and recycling of agricultural water.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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• pp.522.3-523
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• 1986

A Screening test was carried out for chitin-decomposing bacteria. In 100 samples from soil, fesh water and sea water, 7 strains of Chitinolytic bacteria were isolated. 5-3K which exhibited the highest chitinase activity was identified as Aeromonas hydrophila and cultural conditions from maximum chitinase production were determined. Optimum Chitinase production was obtained at pH 7, 33eC and with chitin concentration greater tham 0.2% Under optimal conditions, high yields of Chitinase were obtained in 16-30 hours. Chitinase was purified by ammonium sulfate precipitation and sephadex G-100 gel-filtration from the culture filtrgte.

• Microbiology and Biotechnology Letters
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• v.28 no.4
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• pp.214-218
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• 2000

The inulinase producing microorganism was isolated from soil and tentatively identified as Arthrobacter protophormiae/ramosus. Inulinase was pruified by ethanol precipitation, DEAE-Sephadex ion exchange chromatography and Sephadex gel filtration chromatography. The molecular weight of the purified enzyme was 34 kDa. The specific activity, yield and purity were 31.5 Unit/mg, 19.5% and 18.5 fold, respectively. Optimal pH and temperature for reaction of the purified inulinase were 8.5 and $55^{\circ}C$, respectively. The enzyme was stable at pH 7.5, below$ 55^{\circ}C$, and the activity was stimulated Mg2+.

• Microbiology and Biotechnology Letters
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• v.22 no.2
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• pp.169-174
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• 1994

Antitumor antibiotic HS-1 was purified from the culture broth of a streptomyces floridae SHS-1372 which had been isolated from soil, by solvent extraction, silica gel column chromatography and gel filtration. It was confirmed that HS-1 was active against gram positive bacteria and cancer cells(K562, P388, MCF-7, HT-29). Through the analysis of UV spectrum, melting point, IR spectrum, FAB-MS, $_{1}$H-NMR, $_{13}$C-NMR, 2D-NMR spectra, HS-1 could be identified sa the actinomycin X$_{2}$ antibiotics containing actinocine chromophore and peptides consisted of threonine, proline, methylvaline, sarcosine, D-valine and 4-ketoproline.