• 한국지하수토양환경학회지:지하수토양환경
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• 제19권3호
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• pp.15-24
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• 2014

Soil pollution has been recognized as a serious problem because it causes groundwater pollution through medium contacts. Although concentration of individual chemical could be more easily measured by physico-chemical analysis, it is not easy to consider the bioavailability of edaphic receptors living in soil or groundwater. To measure the toxicity of soil, the soil extracts (soil elutriates or soil suspensions in the other words) are often used due to the difficulties of extracting soil pore water. In this study, we reviewed 15 toxicity test methods found in literature to analyze the detail of each extraction method and to recommend the most frequently used extraction methods. The identified most commonly used extraction methods are as following: The 1 : 4 soil:water ratio, 24 hours shaking time, room temperature, dark, and separation of supernatant using a $0.45{\mu}m$ pore size filter.

• 한국토양비료학회지
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• 제19권4호
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• pp.321-325
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• 1986

유효규산함량이 61 ppm 사양토(砂壤土)에서 규회석(硅灰石) 및 규산질비료시용(珪酸質肥料施用)에 의한 규산용출(珪酸溶出)의 변화(變化)에 관(關)해서 실내(室內) 시험(試驗)을 수행(遂行)한 결과(結果)를 요약(要約)하면 다음과 같다. 1. 규회석(硅灰石) 및 규산질비료(珪酸質肥料)를 토양(土壤)에 처리(處理)하고 증류수(蒸溜水) 및 1N-NaOAc(pH 4.0)로 연속침출(連續浸出)했을 때 각(各) 침출용액중(浸出溶液中)의 규산용출농도(珪酸溶出濃度)는 규회석(硅灰石)보다 규산질비료(珪酸質肥料) 처리(處理)에서 높았다. 2. 규회석(硅灰石) 및 규산질비료(珪酸質肥料)를 토양(土壤)에 처리(處理)하고 증류수(蒸溜水)로 연속침출(連續浸出)했을 때 pH는 규산질비료(珪酸質肥料)보다 규회석처리(硅灰石處理)에서 높았다. 3. 규회석(硅灰石) 및 규산질비료(珪酸質肥料)를 토양(土壤)에 처리(處理)하고 항온(恒溫)했을 때 규회석처리(硅灰石處理)는 시용량(施用量)이 많아짐에 따라 수용액중(水溶液中)의 $SiO_2$ 및 K 농도(濃度)는 낮아졌고 규산질비료(珪酸質肥料)에서는 높아졌으며 pH, Ca 및 Mg 농도(濃度)은 두비종(肥種) 모두 높아졌다. 4. 토양(土壤)에 pH를 달리하여 규산용액(珪酸溶液)을 흡착(吸着)시킨 결과(結果) pH 9.4 정도(程度)에서 최대(最大)로 흡착(吸着)되었다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1998년도 공동 심포지엄 및 추계학술발표회
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• pp.183-188
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• 1998

The efficiency of removing cadmium, copper, and lead from a contaminated soil of abandoned metal mine was studied in a laboratory investigation where citric acid were used to extract the metal from the soil. The contamination level of Pb, Cu in the soil A were 875.5, 667.5mg/kg respectively. The mobility and bioavailability of the metals in soil were also estimated by Sequential Chemical Extractions. Citric acid were examined for its potential extractive capabilities. Concentrations of the acid examined in this study ranged from 0.025 to 0.15M. The pH of the suspensions and S/S ratio in which the extractions were performed ranged from 2.4 to 8.1, and from 2.1:1 to 20:1. Results showed that the removal of contaminant using citric acid was pH and S/S raton dependent.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2001년도 봄 학술발표회 논문집
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• pp.559-562
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• 2001

There are many engineering applications that demand settling acceleration and volume reduction of fine solid suspensions. It is a matter to Improve the dredged soil thickening as well as the dewatering characteristic, because settling acceleration of dredged soil decreases the scale of industrial process and volume reduction of dredged soil decreases environmetal challenge to the disposal sites. Direct electric current induces the movement of fine solid particles suspended in water. Upon formation of a soil structure, the current further induces the movement of water and contaminant in the soil skeleton. Theses phenomena are known as electrokinetics. This study investigates the viability, of using the technique of electrokinetic dewatering to river dredged soil for settling acceleration and volume reduction. The aspect, such as sedimentation velocity, final volume and current variation are discussed.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2000년도 추계학술대회
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• pp.196-201
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• 2000

The influence of adsorption on cadmium toxicity to soil microorganisms in smectite-rich soils and sediments was quantified as a function of solution and sorbent characteristics. Adsorption and surface complexation experiments were conducted to infer Cd sorption mechanisms to a reference smectite and three fractions of a Veritsol soil, and to elucidate the effects of the surface complexation on Cd bioavailability and toxicity in soils and sediments. Cadmium adsorption isotherms conformed to the Langmuir adsorption model, with adsorptive capacities of the different samples dependent on their characteristics. Equilibrium geochemical modeling (MINTEQA2) was used to predict the speciation of Cd in the soil suspensions using Langmuir and Triple Layer surface complexation models. The influence of adsorption and surface complexation on cadmium toxicity to soil microorganisms was assessed indirectly through the relative change in microbial hydrolysis of fluorescein diacetate (FDA) as a function of total Cd concentration and sorbent characteristics. Adsorption decreased the toxicity of Cd to soil microorganisms. Inner-sphere complexation is more effective than outer-sphere complexation in reducing the bioavailability and toxicity of heavy metals in soils and sediments.

• Environmental Engineering Research
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• 제9권1호
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• pp.1-12
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• 2004

• The Plant Pathology Journal
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• 제37권6호
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• pp.596-606
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• 2021

Soil-borne diseases are the major problems in mono cropping. A mixture (designated LTM-m) composed of agricultural wastes and a beneficial microorganism Streptomyces saraceticus SS31 was used as soil amendments to evaluate its efficacy for managing Rhizoctonia solani and root knot nematode (Meloidogyne incognita). In vitro antagonistic assays revealed that SS31 spore suspensions and culture broths effectively suppressed the growth of R. solani, reduced nematode egg hatching, and increased juvenile mortality. Assays using two Petri dishes revealed that LTM-m produced volatile compounds to inhibit the growth of R. solani and cause mortality to the root knot nematode eggs and juveniles. Pot and greenhouse tests showed that application of 0.08% LTM-m could achieve a great reduction of both diseases and significantly increase plant fresh weight. Greenhouse trials revealed that application of LTM-m could change soil properties, including soil pH value, electric conductivity, and soil organic matter. Our results indicate that application of LTM-m bio-organic amendments could effectively manage soil-borne pathogens.

• 미생물학회지
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• 제7권1호
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• pp.29-40
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• 1969

Two kinds of organic materials, powders of Salicornia and Oryza sativa L. wre added as a source of organic matter to the suspensions of saline soils(soil : water = 1:3) to be 4 per cent of dried saline soil grams. And then, the samples were incubated at $28^{\circ}C$ to improve the decomposition of organic materials by soil microflora. Resutls of this experiment are summarized as followings : 1) The pH of soil suspension showed its highest value on the second or third week after the treatments, which were similar to those of the soil microflora. Results of this experiment are summarized as follwings : 1) The pH of soil suspension showed its highest value on the second ot third week after the treatments, which were similar to those of the soil microflora populations. 2) Salinity increased up to the second week and the highest value of it appeared in the samples which were treated with the powder of Salicornia. In general, the salinity of all samples decreased on the third week after the treatment. The fact was assumed the possibilities of desalination from saline soil by the microbial actions. 3) Soil microflora such as bacteria, actinomycetes and fungi, were determined its populations soil microflora is to act as decomposer in soil. Both of the bacteria and actinomycytes population showed in the third weak after the tratment. In general, 30-years old of saline soil contained microbial population much more than those of 5-year old of saline soil. Salicornia powder favored the increase of both the bacteria and fungal population, and Oryza sativa L. seemed to have been a great role in increase of actinomycetes. Especially, fungal population of the untreated soil suspension contained higher microbial populations more than those of the soils treated with both of the organic materials. 4) Sugar contents of soil suspesions decreased remarkably on the first week after the treatments. 5) The amount of nitrate had similar tendency to those of population changes of soil microflora. Total acidity decreased continuously and the amount of potassium showed its highest value on the third week treatment. However, the amount of phosphorus was determined to be insignificant.

• 한국농공학회지
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• 제30권4호
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• pp.127-133
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• 1988

This study was performed to obtain the basic data analyzing salt movement and desalinization effects, and two different desalinization experiments through leaching and rinsing were carried out, using samples of silt loam soil and silty clay loam soil collected in reclaimed tidelands. The relationships between the electrical conductivity of saturation extract and the electrical conductivity at various dilutions, and the correlations between electrical conductivity, total salt concentration, exchangeable sodium percentage and pH during the desalinization of reclaimed tidelands, were analyzed by the statistical method. The results obtained from this study were summarized as follows: 1.The sample soils used in this study were saline-sodic soils in accordance with the USDA classi- fication system of salt affected soils. 2.The electrical conductivity of saturation extract could be estimated conveniently, using the electrical conductivity of extract from various different soil-water suspensions. 3.The total salt concentration could be expressed in the electrical conductivity, but there was a little difference by soil textures. 4.The regression analysis showed that the relationship between the electrical conductivity of saturation extract and the exchangeable sodium percentage during the desalinization of reclaimed lands could be described by a linear regression equation. 5.The value of pH showed a tendency to increase according as the exchangeable sodium percentage decreased during the desalinization of reclaimed tidelands.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 추계학술발표회
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• pp.123-127
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• 2003

Changes in pyrene partitioning due to mineral surface adsorptive fractionation processes of humic substances (HS) were examined in model environmental systems. For purified Aldrich humic acid(PAHA), carbon-normalized pyrene binding coefficients ( $K_{oc}$ ) for the residual (i.e., nonadsorbed and dissolved) PAHA components were different from the original dissolved PAHA $K_{oc}$ , value prior to contact with mineral suspensions. A positive correlation between the extent of pyrene binding and weight-average molecular weight (M $W_{w}$) of residual PAHA components was observed, which appeared to be unaffected by the specific mineral adsorbents use and fractionation mechanisms. A similar positive correlation was not observed with the adsorbed PAHA components, suggesting that conformational changes occurred for the mineral-associated components upon adsorption. Nonlinear pyrene sorption to mineral-associated PAHA was observed, and the degree of nonlinearity is hypothesized to be dependent on adsorptive fractionation effects and/or structural rearrangement of the adsorbed PAHA components.s.