• Journal of Microbiology and Biotechnology
• /
• v.14 no.2
• /
• pp.401-410
• /
• 2004

Soil samples from five different areas in Korea were collected during 2001/02 and examined for presence of the genus Clostridium. Direct immuno-fluorescent assay (IFA) examination showed that Clostridium septicum, Cl. novyi and Cl. chauvoei were detected in the soil of specific areas in Korea. Sixteen species of Clostridium were isolated and cultivated from the soil samples. Cl. peifringens was detected in all sampling locations, while the other species were not. The in vitro activity of 14 antibiotic agents was determined against 421 clostridia isolated from the soil contaminated with animal feces in Korea. Trovafloxacin was effective against all isolates of the genus Clostridium except one isolate of Cl. subterminale, two of Cl. tetani, and three of Cl novyi with $MIC_{50}$ $8- 16\mu$g $ml^{-1}$. Thirteen species of Clostridium were resistant to vancomycin except for Cl. perfringens, Cl. sporogenes, and Cl. subterminale. Imipenem and trovafloxacin showed high antimicrobial activities (>95%) against all strains in the clostridia investigated. Therefore, antibiotic agents such as imipenem and trovafloxacin are the most suitable agents for polymicrobial infection as broad-spectrum monotherapy.

• Journal of Environmental Science International
• /
• v.16 no.6
• /
• pp.725-733
• /
• 2007

The contents of five heavy metals such as lead, cadmium, zinc, copper and manganese in soil and vegetables collected from four sites in Busan district with composite sampling method were determined with ICP emission spectrometer. The ranges of their contents in soil were lead, $1.65\sim4.36ppm;$ cadmium, $0.05\sim0.09ppm;$ zinc, $6.33\sim11.09ppm;$ copper, $0.44\sim1.35ppm;$ manganese, $8.40\sim19.39ppm$, respectively. These contents were lower than the Clarke number. The range of heavy metal contents in four vegetables such as lettuce, radish and its roots, spinach and cabbage were lead, $0.09\sim0.48ppm;$ cadmium, $0.01\sim0.08ppm;$ zinc, $1.81\sim14.62ppm;$ copper, $0.14\sim1.87ppm;$ manganese, $0.71\sim14.5$ 5ppm with the order of Zn(7.30 ppm)>Mn(4.35 ppm)>Cu(0.53 ppm)>Pb(0.19 ppm)>Cd(0.04 ppm) in average contents. The average transfer ratio of metals from soil to vegetables was order of Zn(77.8 %)> Cd(37.5 %)>Cu(34.5 %)>Mn(18.6 %)>Pb(6.7 %). In case of the same cultivating soil, the transfer ratio could be expected to the order of spinach$lettuce{\approx}cabbage$

• Environmental Engineering Research
• /
• v.18 no.1
• /
• pp.37-43
• /
• 2013

Water distribution pipes installed underground have potential risks of pipe failure and burst. After years of use, pipe walls tend to be corroded due to aggressive soil environments where they are located. The present study aims to assess the degree of external corrosion of a distribution pipe network. In situ data obtained through test pit excavation and direct sampling are carefully collated and assessed. A statistical approach is useful to predict severity of pipe corrosion at present and in future. First, criteria functions defined by discriminant function analysis are formulated to judge whether the pipes are seriously corroded. Data utilized in the analyses are those related to soil property, i.e., soil resistivity, pH, water content, and chloride ion. Secondly, corrosion factors that significantly affect pipe wall pitting (vertical) and spread (horizontal) on the pipe surface are identified with a view to quantifying a degree of the pipe corrosion. Finally, a most reliable model represented in the form of a multiple regression equation is developed for this purpose. From these analyses, it can be concluded that our proposed model is effective to predict the severity and rate of pipe corrosion utilizing selected factors that reflect the fuzzy soil environment.

• Journal of Soil and Groundwater Environment
• /
• v.19 no.6
• /
• pp.18-23
• /
• 2014

The BTEX contamination of soil around gas station in Korea was investigated in 53 gas stations in 2013 by official test method on soil pollution. Each gas station was divided into oil tank area, line area, and surrounding area. The concentration of BTEX in 1066 sites of 53 gas stations was N.D.~ 3437.36 mg/kg. The order of average concentration for area was as follows: line area ($20.91{\pm}144.79mg/kg$) > tank area ($15.11{\pm}110.08mg/kg$) > surrounding area ($10.79{\pm}111.40mg/kg$). It was the number of sampling site exceeding regulatory levels at surrounding area the most at all. The average concentration of xylene was the highest, while that of ethylbenzene was the lowest.

• Journal of Biosystems Engineering
• /
• v.36 no.1
• /
• pp.33-39
• /
• 2011

An optical sensing approach based on diffuse reflectance has shown potential for rapid and reliable on-site estimation of soil properties. Important sensing ranges and the resulting regression models useful for soil property estimation have been reported. In this study, a similar approach was applied to investigate the potential of reflectance sensing in estimating soil properties for Korean paddy fields. Soil cores up to a 65-cm depth were collected from 42 paddy fields representing 14 distinct soil series that account for 74% of the total Korean paddy field area. These were analyzed in the laboratory for several important physical and chemical properties. Using air-dried, sieved soil samples, reflectance data were obtained from 350 to 2500 nm on a 3 nm sampling interval with a laboratory spectrometer. Calibrations were developed using partial least squares (PLS) regression, and wavelength bands important for estimating the measured soil properties were identified. PLS regression provided good estimations of Mg ($R^2$ = 0.80), Ca ($R^2$ = 0.77), and total C ($R^2$ = 0.92); fair estimations of pH, EC, $P_2O_5$, K, Na, sand, silt, and clay ($R^2$ = 0.59 to 0.72); and poor estimation of total N. Many wavelengths selected for estimation of the soil properties were identical or similar for multiple soil properties. More important wavelengths were selected in the visible-short NIR range (350-1000 nm) and the long NIR range (1800-2500 nm) than in the intermediate NIR range (1000-1800 nm). These results will be useful for design and application of in-situ close range sensors for paddy field soil properties.

• Journal of the Korean Geotechnical Society
• /
• v.20 no.2
• /
• pp.131-141
• /
• 2004

For geotechnical applications, engineers use data obtained from a site investigation to interpret the structure and potential behavior of the subsurface. In most cases, these data consist of samples that represent 1/100,000 or less of the total volume of soil. These samples and associated field and lab testing provide the information used to estimate soil parameter values. The resulting values are estimated ones and there exists some likelihood that actual soil conditions are significantly different from the estimates. This may be the case even if the sampling and interpretation procedures are performed in accordance with standard practice. Although these efforts have been made to characterize the uncertainty associated with geotechnical parameters, there is no commonly accepted method to evaluate quantitatively the quality of an investigation plan as a whole or the relative significance of individual sampling points or potential sampling points.

• Journal of Ecology and Environment
• /
• v.36 no.1
• /
• pp.19-29
• /
• 2013

Cicuta virosa is an endangered species in Korea, which is a southern marginal area. To conserve and restore habitats of this plant, we investigated water and soil environmental characteristics and vegetation at four habitats during the growing season. The C. virosa habitats differed in community structure, water and substrate properties, and water regime. Although the total distribution ranges of the water and soil environments for C. virosa were wide and overlapped with the optimal environmental range of distribution of accompanying species, the optimal water level range for C. virosa was defined as $7{\pm}3.5$ cm. Water level was adjusted by substrate structure such as a mound of P. japonica and a floating mat comprised of accompanying species. A floating mat was an aid to maintain an optimal and stable water level in deep or fluctuating water and to prevent strong competition with prolific macrophytes. The GS sampling site, which had floating mats, could be a good model for C. virosa conservation in a warm temperate region, whereas the PC sampling sites, which experienced a water shortage in spring, provided a clue about the decline in C. virosa population size.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2009.03a
• /
• pp.977-986
• /
• 2009

Sampling disturbance can introduce considerable errors in the laboratory estimation of geotechnical properties of soils, and the results obtained from sophisticated sampling and careful laboratory testing are not matching with field behavior. Therefore, it is advantage to adopt in-situ testing techniques for the estimation of geotechnical parameters. Therefore, Screw plate loading test, one of new field test technologies, has been investigated in this study. This test can be utilized to find out important properties of soils such as load-displacement, elastic modulus, and shear strength. The screw plate loading test modified from the plate loading test is an experiment underneath ground by inserting a spiral type of auger screw. The structure and characteristics of the screw plate loading test device was examined in detail. In addition, The new screw plate loading test device was manufactured to refer the previous studies. The reliability of developing screw plate loading test was examined through the analysis of the laboratory test.

• Membrane and Water Treatment
• /
• v.10 no.4
• /
• pp.313-320
• /
• 2019

Increasing the concentration of nitrate ions in the soil solution and then leaching it to underground aquifers increases the concentration of nitrate in the water, and can cause many health and ecological problems. This study was conducted to evaluate the vulnerability of Meymeh aquifer to nitrate pollution. In this research, sampling of 10 wells was performed according to standard sampling principles and analyzed in the laboratory by spectrophotometric method, then; the nitrate concentration zonation map was drawn by using intermediate models. In the drastic model, the effective parameters for assessing the vulnerability of groundwater aquifers, including the depth of ground water, pure feeding, aquifer environment, soil type, topography slope, non-saturated area and hydraulic conductivity. Which were prepared in the form of seven layers in the ARC GIS software, and by weighting and ranking and integrating these seven layers, the final map of groundwater vulnerability to contamination was prepared. Drastic index estimated for the region between 75-128. For verification of the model, nitrate concentration data in groundwater of the region were used, which showed a relative correlation between the concentration of nitrate and the prepared version of the model. A combination of two vulnerability map and nitrate concentration zonation was provided a qualitative aquifer classification map. According to this map, most of the study areas are within safe and low risk, and only a small portion of the Meymeh Aquifer, which has a nitrate concentration of more than 50 mg / L in groundwater, is classified in a hazardous area.

• Journal of Environmental Science International
• /
• v.22 no.1
• /
• pp.119-129
• /
• 2013

We compared equilibrium evaporation($E_{equili}$) eddy-covariance($E_{eddy}$) with soil moisture data($E_{SMseries}$) which were measured with a 2 hours sampling interval at three points for a humid forest hillslope from May 5th to May 31th in 2009. Accumulations of $E_{eddy}$, $E_{equili}$ for the study period were estimated as 2.52, 3.28 mm and those of $E_{SMseries}$ were ranged from 1.91 to 2.88 mm. It suggested that the eddy-covariance method considering the spatial heterogeneity of soil evaporation is useful to evaluate the soil evaporation. Method A, B and C were proposed using mean meterological data and daily moisture variation and the computations were compared to eddy-covariance method and equilibrium evaporation. The methods using soil moisture data can describe the variations of soil evaporation from eddy-covariance through simple moving average analysis. Method B showed a good matched with eddy-covariance method. This indicated that Dry Surface Layer (DSL) at 14:00 which was used for method B is important variable for the evaluation of soil evaporation. The total equilibrium evaporation was not significantly different to those of the others. However, equilibrium evaporation showed a problem in estimating soil evaporation because the temporal tendency of $E_{equili}$ was not related with the those of the other methods. The improved understanding of the soil evaporation presented in this study will contribute to the understandings of water cycles in a forest hillslope.