• Korean Journal of Soil Science and Fertilizer
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• v.39 no.6
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• pp.329-333
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• 2006

Most of volcanic ash soils in South Korea are distributed in Jeju province which is an island placed on southern part of Korea and has steep slope mountain area. There are many soils containing high contents of organic matter (OM) derived from volcanic ash in Jejudo, also. Therefore, irrigation and drainage in volcanic ash soil different with general soil which has low OM content have to be applied with another management way, but studies searching appropriate methods for them are set on insufficient situation because the area of volcanic ash soil in South Korea is only 1.3% (130,000ha). This study was conducted for analysis of soil water content and irrigation quantity appropriate for crops cultivated in volcanic ash soil with high OM content. Although soils with different soil color have the same soil texture, soil water characteristics curve by soil color showed the difference of water retention capability by OM content. But, this characteristics classified with soil color could be unified by scaling technique with similitude analysis method which get dimensionless water content using a present water content, a residual water content and saturated water content (or water content at 10kPa). A relation of gravimetric soil water content (GSWC) and dimensionless water content by the results showed a form of power function. The dimensionless water content (DWC) express a relative saturation degree of present water content. This was also expressed by van Genuchten model which describe the relation between relative saturation degrees and matric potentials. These results on soil water characteristics curve (SWCC) of volcanic ash soil will be the basic of irrigation plan in area having high organic contents into soil.

• Economic and Environmental Geology
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• v.47 no.5
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• pp.467-477
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• 2014

Naturally occurring asbestos (NOA) occurs in rocks and soils as a result of natural weathering and human activities. The asbestos have been associated with ultramafic and mafic rocks, and carbonate rock. The previous studies on NOA were mainly limited to ultramafic and mafic rock-hosted asbestos in Korea. But, studies on carbonatehosted asbestos are relatively rare. Therefore, the purposes of this study were to investigate mineralogical characteristics of carbonate-hosted and metapelite-hosted NOA and to examine genesis of NOA occurred in the both rocks. The study area was Daerori, Seosan, Chungnam Province, Korea. The major rock formation consisted of limestone and schist which have been known to contain asbestos. Sampling was performed at outcrop which contained carbonate rock showing acicular asbestos crystals as well as pegmatitic intrusion that contacted with carbonate rock. PLM, XRD, EPMA, and EDS analyses were used to characterize mineral assemblages, mineralogical characteristics, and crystal habits of amphiboles and other minerals. BSEM images were also used to examine the genesis of asbestos minerals. The amphibole group was observed in all of the carbonate rocks, and actinolite and tremolite were identified in all rocks. These mineral habits were mainly micro-acicular crystals or secondary asbestiform minerals on the surface of non-asbestiform minerals appearing split end of columnar crystals produced by weathering. BSEM images showed residual textures of samples. The residual textures of carbonate rocks showed dolomite-tremolite-diopside mineral assemblages that formed during prograde metasomatism stage. Some carbonate rock also showed diopside-tremolite-talc mineral assemblages which were formed during retrograde metasomatism stage, as the residual textures. In result the presence of asbestos actinolite-tremolite in the carbonate rocks were confirmed in the areas where actinolite-tremolite asbestos was influenced by low temperature hydrothermal solution during metasomatism stage. These asbestos minerals showed the acicular asbestiform minerals, but even non-asbestiform minerals, a bundle or columnar shape, could transform to asbestiform minerals as potential NOA by weathering because the end of columnar shape of non-asbestiform minerals appeared as multiple acicular shaped fibers.

• The Korean Journal of Pesticide Science
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• v.20 no.4
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• pp.319-325
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• 2016

This study was conducted to investigate residual organochlorine pesticides in green house soil and oriental melon, green pepper, and lettuce. The majority of them were designated as persistent organic pollutants (POPs) by the international community at the Stockholm Convention on Persistent Organic Pollutant. Extraction and clean-up method were developed using the QuEChERS method for residual organochlorine pesticides (OCPs) in soil and oriental melon, green pepper and lettuce. Recovery of OCPs in greenhouse soil and oriental melon, green pepper, and lettuce ranged from 73.3-110.6%. Limit of detection (LOD) of OCPs in soil and 3 crops were 0.01-0.08 and $0.11-0.17{\mu}g/kg$. The residues of OCPs in oriental melon, green pepper and lettuce greenhouse soil were analyzed by the developed method, and dieldrin, ${\beta}-endosulfan$ and endosulfan sulfate were detected at 1.4-72.5, 0.1-78.7 and $0.0-214.1{\mu}g/kg$, respectively. The detection frequency of 3 compounds in soils were 52 (29.7%), 34 (19.4%) and 57 (32.6%) among 175 samples, respectively. However, these compounds were not detected in all crop samples. The residue level in 3 crops were lower than 1/58.8 of maximum residue level of them. These results showed that the OCPs residue in oriental melon, green pepper, and lettuce greenhouse soil were not as high as crop safety threatening.

• The Korean Journal of Pesticide Science
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• v.11 no.2
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• pp.95-105
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• 2007

The aim of this study was to determine the residual amounts of PAHs in environmental samples such as crop, soil and water collected from paddy, upland fields and forestlands near industrial zone and/or a thermal power plant in South Korea. All of the samples were analyzed by GC-mass spectrometer. The average contents of total PAHs in soil samples were 140.2 ${\mu}g\;kg^{-1}$ and the range was from 4.3 to $662.9{\mu}g\;kg^{-1}$. The detection of benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene and dibenzo(a,h) anthracene which have strong carcinogenecity was ranged from 14.2 to 167.8 ${\mu}g\;kg^{-1}$. The residual amounts and detection frequency of PAHs in soil samples from the iron and heavy industrial areas near Pohang and Busan were 3-folds more than those of the other areas. Amounts of PAHs in upland soil samples was 1.5 folds higher than those of paddy soil samples, suggesting that it may be related to the content of organic matter in soil. The average contents of total PAHs in crop samples were 9.7 ${\mu}g\;kg^{-1}$ which ranged from 4.5 to 52.2 ${\mu}g\;kg^{-1}$. However, the residual amounts of PAHs in water samples were not detected. These results showed that soils and crops were slightly contaminated with PAHs. Therefore, the investigation should be continued for evaluating a safety or risk assessment through expansion of regions and crops.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.3
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• pp.224-231
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• 1984

Four kinds of soil conditioners, such as red earth, clayey tidal deposit, silty tidal deposit and tertiary deposit were evaluated for the rice growth and for the effectiveness of soil improvement in sandy paddy soil (Gangseo series) whose percolation and nutrient leaching are usually severe. Experiment was conducted at the farmer's field in Hackpo Ri, Bugog Myeon, Changyeong Gun, Gyeong Nam Province for two years (1980-1981) with using two rice varieties, Milyang 42 for 1980 and cheongcheongbyeo for 1981. For both experimental years, the grain yields were increased on the plots that were treated with soil conditioners compared with nontreated plot. The increase in grain yield was particularly high on the plots treated with clayey tidal deposit and teritary deposit. The dry weight of the plant and the uptake amount of inorganic ingredient tended to increase on the plots of clayey tidal deposit and tertiary deposit during whole rice growing season because of the residual effect of soil conditioners in the second experimental year. Cation exchange capacity, available silicate, exchangeable potassium and active iron was increased by the treatment with the soil conditoners. Especially cation exchange capacity was highest in the tertiary deposit treatment plot. Aggregation content and plastic index were increased for the all treatment plots with soil conditioner, however, hydraulic conductivity was conspicuously decreased by the tertiary deposit and clayey tidal deposit treatments.

• Korean Journal of Environmental Agriculture
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• v.29 no.1
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• pp.47-53
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• 2010

The purpose of this study was to investigate the effectiveness of a stabilization treatment for As contaminated soil. A combination of hydrated lime, Portland cement, $FeCl_3{\cdot}6H_2O$, and NaOH were used as stabilizing agents. The effectiveness of stabilization treatment was evaluated by the Korean Standard Test (KST) method (1N HCl extraction). Sequential extractions were performed to investigate the As distribution after treatment. Following the application of the treatment, curing periods of up to 7 and 28days were investigated. The experimental results showed that a combination of hydrated lime/Portland cement was more effective than treatments of hydrated lime or Portland cement at immobilizing As in the contaminated soil. The treatment of 25wt% hydrated lime and 5wt% Portland cement was effective in reducing As leachability less than the Korean warning standard of 20 mg/kg. However, the treatments of hydrated lime and Portland cement failed to meet the Korean warning standard even when up to 30 wt% was used. The treatment utilizing hydrated lime and $FeCl_3{\cdot}6H_2O$ was not effective in properly reducing As leachability. The addition of $FeCl_3{\cdot}6H_2O$ was negative in terms of pH condition. Moreover, the treatment with hydrated lime/NaOH was effective in reducing As leachability but not as much as hydrated lime/Portland cement. The sequential extraction results indicated that the residual phase was greatly increased upon the treatment of hydrated lime/Portland cement. It was concluded that the hydrated lime/Portland cement treatment was the best among the other combinations studied at achieving trace As concentrations.

• Journal of the Korean Geotechnical Society
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• v.27 no.2
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• pp.43-52
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• 2011

The characteristics of shear zone in granular soils largely affect the stability of geo-structures. The goal of this study is to evaluate shear zone in a direct shear test using shear wave, electrical resistivity, and cone tip resistance. Bender elements and electrical resistivity probe are embedded into the wall of a direct shear box made of transparent acrylic material to estimate the shear wave velocities and the electrical resistivity at shear and non-shear zones. At the point of peak and residual strength, micro cone penetration test which can be available to measure tip resistance has been performed. Experimental results show that the shear wave velocities at upper shear zone increase during shearing while the values remain constant at bottom and lower shear zone. Also, resistivities at lower shear zone depend on relative density while resistivities at bottom remain constant. The results of cone penetration test demonstrate the correlation of the cone tip resistance and small strain shear modulus at shear zone. This study suggests that the application of the modified direct shear box including shear wave, electrical resistivity and the micro cone tip resistance may become effective tools for analyzing the characteristics of a shear zone.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.4
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• pp.401-406
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• 1992

Antifungal substances against three plant pathogenic fungi, Phytophthora capsici, Phytophthora nicotianae var. parasitica and Rhizoctionaia solani were fractionated cultures of Streptomyces sp. A-2 strain isolated in Korean soils. Characterizations of active substances related with antagonistic effects were follows : 1. The excellent media which showed the transfer efficiency of antagonistic substances from Streptomyces sp. A-2 strain G.Y.B and B.H.I. among four that are glucose yeast broth (G.Y.B), $M\ddot{u}eller$, brain heart infusion(B.H.I.) and Czapek media. Active substances which were transfered into ethylacetate or left in residual aqueous phase did not lose antagonistic activity in spite of autoclavation. This indicated that bonds of these compounds were rigid enough to keep activity under such conditions. 2. Antagonistic substances were extracted according to adjustment of pH 3 or pH12 to 5 day-old B.H.I. broth cultures of Streptomyces sp. A-2 strain. Comparative analysis fluorescent bands on HPTLC to antagonsitic spectra against three phytopathogenic fungi indicated that major substances with antagonistic activity were extracted regardless of different pH adjustment to broth cultures. Since UV spectrum of these fractions scanned from 500nm to 200nm was similiar to that of polyene macrolide, major substances related with antagonistic activities were assumed to be polyene derivatives antibiotics.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.4
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• pp.628-634
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• 2012

Release of veterinary antibiotics (VSs) to agricultural environment through application of animal manure and/or animal manure-based composts to soils is of concern. The current study was conducted to examine decline of VAs during composting the chicken manure. For this, antibiotics free chicken manure (20 kg) and sawdust (10 kg) were added to the bench-scale composting apparatus and then the mixed material was spiked simultaneously with three VAs (chlortetracycline, CTC; sulfamethazine, SMZ; tylosin, TYL) at two different levels (10 and $20mg\;kg^{-1}$). Then the decline of VAs was determined using Charm II system during 53 composting period. For comparison, composting only chicken manure was included at VAs concentration of $10mg\;kg^{-1}$. During composting, the concentration of all three different VAs declined below the prospective guideline values ($0.8mg\;kg^{-1}$ for CTC, $0.2mg\;kg^{-1}$ for SMZ, and $1.0mg\;kg^{-1}$ for TYL) except CTC at $20mg\;kg^{-1}$ spiking when the chicken manure was composted together with sawdust. Interestingly, CTC at $10mg\;kg^{-1}$ spiking appeared to be declined under the guideline value without sawdust while SMZ was resistant to be declined without sawdust. Unlike CTC and SMZ, TYL showed immediate decline right after spiking TYL to composting materials regardless the spiking concentration and existence of sawdust. Appropriate composting procedure of chicken manure was able to decline the residual VAs in the manure below the prospective guideline value and the importance of organic substances on this decline was perceived.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.12
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• pp.1105-1112
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• 2009

Antibiotics are biologically active substances and commonly used for therapeutic treatment of infectious disease in humans and for treating and protecting the health of animals. In recent years, antibiotics have attracted worldwide attention because of their side effects on the environment. Consequently, efforts have been made to monitor the residual of antibiotics in the environment. This study tested the mobility of tetracyclines and sulfonamides in soil and leachate through column experiments. The three tetracycline antibiotics showed higher mass recovery rates in all kinds of soils(28.00~44.11%) than in leachate(10.54~27.43%). This seems attributable to the high adsorption coefficient values($K_d$) of tetracyclines representing strong and active adsorbability to organic and mineral phases in soil, ending up relatively small amount being detected in surface water. By contrast, the sulfonamides(sulfamethazine and sulfathiazole) showed higher mass recovery rates in leachate(23.19~26.20%) compared to in soil(10.41~14.21%) due to lower adsorption coefficient values and higher mobility of sulfonamides, enabling easier movement to surface water through the runoff in the environment.