• Journal of the Korean GEO-environmental Society
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• v.2 no.2
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• pp.5-12
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• 2001

The physical characteristics and contaminant level of the dredged material generated by the channel maintenance and water quality improvement was analysed in a series of the study of the beneficial uses of dredged material in harbor. Dredged materials were sampled at Kunsan, Kohyun, Samchunpo, and Pohang Harbors and tested in the laboratory(leaching Test). From the experimental results, the specific gravity does not shows large differences, while almost grains are composed of silts and oyster shells except Pohang harbor containing gravels. The COD release rate and ignition loss is high in Kunsan dredged materials because of the watershed pollutants loads. The nutrient release rate is also relatively high. The release concentration of the heavy metals shows the highest values on Zn, Pb, Cd, Cu constituents at Kohyun, Kunsan, Samchunpo, Kunsan, respectively.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1647-1654
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• 2008

The characteristics of arsenic(As) contamination were investigated on soils of 3 abandoned metal mine sites in Gangwon-do, Korea. Total forty nine soils were sampled to conduct standard methods(extraction by 1HCl), sequential extraction and column leaching test. Concentration of As extracted by 1N HCl was ordered as follows: A mine > B mine > C mine, and the concentration of arsenic in the soils of A mine was significantly greater than that at any other cases and all samples of A mine were exceeded the national regulation of $6mg \;kg^{-1}$. In the results of sequential extraction, the potential contamination risk for groundwater and plants was ordered as follows: C mine > B mine > A mine because the C mine showed the relatively greater mobility and bioavailability of fraction than any other mines. And, in colume test, concentration of As was ordered as follows: C mine > B mine > A mine, and it was expected that these results were connected with fraction characteristics of the mine sites. Therefore adequate leaching investigations should be used to simulate the effect of natural leaching conditions, and to predict both the potential mobility of metals to groundwater and their bioavailability to plants under natural conditions.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.2
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• pp.161-166
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• 2021

This study was on leaching test(KSLT) of the aggregate for the products to evaluate the characteristics of contaminants and the possibility of contamination arising from the aggregate. On the basis pH, conductivity, turbidity, TN, TP, COD and heavy metal contents in the aggregate increased as the particle size of the aggregate was smaller. The pH appeared to be 9.9~11.4 which is relatively higher than soil, however, heavy metal has investigated within the 1 region's standard value of soil pollution standards. From the leaching test, there is strong indication that the risk of pollution due to elution of pollutants gets higher with the smaller grain size. Especially conductivity and turbidity are the potential water pollution source and recycled aggregates of 10mm or less could be a potential pollution source since it could elute soluble matters and suspended solid, but there is no proper management standard for them. As a result of evaluating water pollution possibility of the aggregate, the pH displayed in items with a very high possibility of contamination, TN and TP did in item with a low possibility of contamination and on the other hand the heavy metals did in item with a very low possibility of contamination.

• Journal of the Mineralogical Society of Korea
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• v.27 no.2
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• pp.73-83
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• 2014

In order to investigate selective phase transformations and to determine the maximum Au leaching factors from microwave treated Au-bearing complex sulfides, a microscope, SEM-EDS analysis, and thiocyanate leaching tests were performed. When the Au-bearing complex sulfides were exposed to microwave heating, increasing the microwave exposure time increased temperature and decreased weight. Arsenopyrite was first selectively transformed to hematite, which formed a concentric rim structure. In this hematite, oxygen and carbon was detected and always showed high iron content and low arsenic content due to arcing and oxidation from microwave heating. The results of the leaching test using microwave treated sample showed that the maximum Au leaching parameters was reached with 0.5 g concentration thiocyanate, 2.0 M hydrochloric acid, 0.3 M copper sulfate and leaching temperature at$60^{\circ}C$. Under the maximum Au leaching conditions, 59% to 96.69% of Au was leached from the microwave treated samples, whereas only 24.53% to 92% of the Au was leached from the untreated samples.

• Geotechnical Engineering
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• v.11 no.3
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• pp.5-16
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• 1995

In this paper, two leaching tests(batch test & column test) were carried out to estimate the detrimental effects of coal ash leachates. The variation of constituents and concentration of coal ash leachate with the lapse of leachins time was analysed through the column tests. From the test results, it was found coal tach can be classified as a general waste, and all other items except pH of coal ash leachate are satisfied the concentration requirements for the drinking water. It was also found the concentration of coal ash rapidly decrease with the lapse of the leaching time and become the insignificant value after an elapsed time.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.424-433
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• 2006

This paper studies the field applicability of the Special Chemical grouting Method(SCM) in reinforcing and reducing permeability of the back of an existing continuous wall. SCM uses double rod which imposes intermediate pressure$(981\sim9,810kPa)$ to disturb, cut, discharge, and mix the ground. It is observed that a bulb is formed by using cement paste and environmentally friendly injection materials with minimal alkali leaching. Uniaxial compression tests, test for chemical properties and fish poison test are performed. Test results indicate that the method results in higher durability, less leaching through use of the environmentally friendly injection material, and faster mobilization of the strength. In addition, field tests confirm the formation of the bulb and the seepage cutoff wall.

• Journal of the Korean Geotechnical Society
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• v.22 no.12
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• pp.25-31
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• 2006

This paper studies the field applicability of the Special Chemical grouting Method (SCM) in reinforcing and reducing permeability of the back of an existing continuous wall. SCM uses double rod which imposes intermediate pressure ($981{\sim}9,810kPa$) to disturb, cut, discharge, and mix the ground. It is observed that a bulb is formed by using cement paste and environmentally friendly injection materials with minimal alkali leaching. Uniaxial compression tests, test for chemical properties and fish poison test are performed. Test results indicate that the method results in higher durability, less leaching through the use of the environmentally friendly injection material and faster mobilization of the strength. In addition, field tests confirm the formation of the bulb and the seepage cutoff wall.

• Economic and Environmental Geology
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• v.34 no.5
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• pp.461-470
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• 2001

The Shihung mine was restored in the early 90's after abandonment for 20 yews since 1973. Although disposed mine tailings were removed and the site was replaced by an incineration plant, still some residual mine tailings remain in the places including the old mine tailing ditposal area and the adjacent agricultural area. These residual mine tailings are prone to impose an adverse impact on the soil and groundwater and needs investigation for the potential contamination. Mine tailing samples were collected from the old tailing disposal area and the iii paddy. The porewater from the mine tailing were extracted and analysed to investigate chemical changes along the reaction path. Batch leaching tests were also carried out in the laboratory to find any supporting evidence found in the field analysis. Evidence of elemental leaching was confirmed both by the mine tailing and the porewater chemistry in them. The element concentrations of Cu, Cd, Pb, Zn in the porewater exceed the standard for drinking water of Korean government and US EPA. Leaching of heavy metals from the mine tailing seem to be responsible for the contamination. In batch leaching test. heavy metals were either continuous1y released or declined rapidly. Combining the information with porewater variation with depths and the geochemical meodeling results, most of elements are controlled by dissolution and/or precipitation processes, with some solubility controlling solid phases (Cu, Pb, Fe and Zn). Batch leaching test conducted at fixed pH 4 showed much higher releases for the heavy metals up to 400 times (Zn) and this area is becoming more vulnerable to soil and groundwater pollution as precipitation pH shifts to acidic condition.

• Korean Journal of Environmental Agriculture
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• v.25 no.1
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• pp.58-63
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• 2006

In order to elucidate the adsorption and leaching characteristics of the insecticide imidacloprid in two types of paddy soils near Suwon, this experiment was carried out with $[^{14}C]$imidacloprid as a radiotracer. In an adsorption study conducted using $[^{14}C]$imidacloprid in 2 test soils, the adsorption coefficient was higher in soil A $(K_f\;2.6)$ than that in soil B $(K_f\;1.7)$. As calculated from Freundlich constant, distribution coefficients and half lives in soils, GUS indices showed low leachabilities of imidacloprid treated on the paddy soils into the groundwater. The amount of imidacloprid leached from the soil columns during the 4 weeks of leaching was less than 2% of the originally treated $^{14}C$. In the leaching test the amounts of $^{14}C$ activities distributed in the soil layer of 0-10 cm were more than 80% of the originally tented $^{14}C$ and those in rice plants were less than 3% of the originally treated $^{14}C$, suggesting that imidacloprid has very low teachability and bioavailability.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.3
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• pp.453-457
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• 2006

A long-term leaching column experiment was performed to evaluate the teachability of the stabilized lead-contaminated soil using soluble phosphate. The study shows that Pb in the leachate was little detected and the remaining $PO_4-P$ concentration kept below 0.1 mg/L due to the formation of geochemically stable lead phosphate minerals from the reactions of labile soil Pb forms with the added soluble phosphate salt. After the experiment, there was no Pb migration from the top to the bottom of the stabilized soil column. But the Pb concentrations of the 12 soil samples from the control column decreased with the increase of the soil depth.