• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.961-967
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• 2012

There have been many studies about efficiency of amendments for heavy metal stabilization through chemical assessment. The objective of this study was to evaluate the efficiency of several soil amendments (lime, agric-lime, dolomite, steel slag, fly ash and acid mine drainage sludge) on heavy metals stabilization through not only chemical but also biological assessments (phytotoxicity test) in abandoned mining area soil. In order to achieve the goal, we conducted preliminary screening experiment targeting 12 types of crop plants such as radish, young radish, chinese cabbage, winter grown cabbage, cabbage, bok choy, chicory, crown daisy, carrot, chives, spinach, and spring onion. The results of inhibition rates of early plant growth in metal-contaminated soil against non-contaminated soil and the correlations between inhibitions items showed that the bok choy was appropriate specie with respect to confirm the effect of several amendments. Several amendment treatments on contaminated soil brought about the changes in the root and shoot elongation of bok choy after 1 week. Agric-lime, dolomite and steel slag treatments showed the great efficiency of reducing on mobility of heavy metals using chemical assessment. But in contrary, these treatments resulted in the reduction of root and shoot elongation and only AMD sludge increased that of elongation, significantly. When considering both chemical and biological assessments, AMD sludge could be recommended the compatible amendment for target contaminated soil. In conclusion, biological assessment was also important aspect of decision of successful soil remediation.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.5
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• pp.265-276
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• 2017

Heavy metals leaching from closed mines have been causing severe environmental problems in nearby soil ecosystems. Mine reclamation in Korea has been recently implemented based on the heavy metal immobilization (a.k.a., stabilization). Since the immobilization temporarily fixes the heavy metals to the soil matrix, the potential risk of heavy metal leaching still exists. Therefore the appropriate monitoring and the related policies are required to safeguard the soils, where all the cultivations occur. The current monitoring methods are based on either heavy metal concentration or simple toxicity test. Those methods, however, are fragmented and hence it is difficult to evaluate the site in an integrated manner. In this study, as the integrated approach, ecological functional state evaluation with a multivariate statistical tool was employed targeting physiochemical soil properties, heavy metal concentrations, microbial enzymatic activity, and arsenic respiratory reductase gene quantity. Total 60 soil samples obtained from three mines (Pungjeong, Jeomdong, Seosung) were analyzed. As a result, the stabilized layer soil and lower layer soil have shown the similar pattern in Pungjeong mine. In contrast, Jeomdong and Seosung mine have shown the similarity between the stabilized layer soil and the cover layer soil, indicating the possible contamination of the cover layer soil.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.296-300
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• 2001

In order to recycle the incineration ash (bottom ash and fly ash) generated from the incineration of municipal waste for a cement material, salts as well as heavy metal should be removed by the stabilization treatment. Most of these heavy metal and over 80% of salts are removed by a washing as a pre-treatment. However, wastewater which is another pollutant is generated by a washing, then proper treatment should be developed. First the characteristics of incineration ashes collected from two domestic full-sized incinerators were investigated and removal rate of salts and heavy metals from them also studied. The wastewater quality was compared to the criteria of the regulation by analyzing the characteristics of generated wastewater during the washing of incineration ash as a condition of liquid/solid ratio. Also, we tried to used this experimental results for the basic data to develop proper processing technique of municipal waste.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1999.10a
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• pp.34-38
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• 1999

This paper investigated remediation options for contaminated sediments with heavy metals. Twenty three sediment samples were taken from three different depths of 0.5m, 1.5m and 2.5m. The concentration of Heavy metals Cu, Pb, and Hg were measured. The concentration of copper far exceeded the Sediment Quality Guideline in U.S.A and Interim Sediment Quality Guidelines in Canada. Therefore, remediation of the sediments is requried to protect the benthos. Two remediation options were suggested : dredging of the organic sediments as deep as about 85cm followed by surface covers with clean soil, and in-situ stabilization of tile sediments using lime or cement followed by surface cover with clean soil.

• Journal of Soil and Groundwater Environment
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• v.21 no.6
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• pp.87-100
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• 2016

Biochar, which has high alkalinity, has widely studied for amendment of soil that contaminated with heavy metals. The aim of this study is assessment of amendment for arsenic and heavy metals contaminated acidic agricultural soil using biochar that derived from buffalo weed (A. trifida L. var. trifida). Pot experiments were carried out including analysis of soil solution, contaminants fractionation, soil chemical properties and plant (lettuce) uptake rate. Arsenic and heavy metals concentrations in soil solution showed relatively low in biochar added experiments when compared to the control. In the heavy metals fractionation in soil showed decrease of exchangeable fraction and increase of carbonates fraction; however, arsenic fractionations showed constant. Soil chemical properties indicated that biochar could induce recovery of soil quality for plant growth in terms of soil alkalinity. However, phosphate concentration in biochar added soil decreased due to Ca-P precipitation by exchangeable calcium from biochar. Arsenic and heavy metals uptake rate of plant in the amended experiment decreased to 50% when compared to the control. Therefore biochar derived from buffalo weed can be used as amendment material for agricultural soil contaminated with arsenic and heavy metals. Precipitation of As-Ca and metal-carbonates are major mechanisms for soil amendment using char.

• The Journal of the Acoustical Society of Korea
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• v.34 no.3
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• pp.200-209
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• 2015

An underwater sound surveillance system detects and tracks enemy ships in real-time using hydrophone arrays, in which seabed-mounted sensor arrays play a pivotal role. In this paper the conceptual design of seabed-mounted, cylindrical hydrophone arrays for use in shallow coastal waters is performed via finite element calculations. To stabilize the receiving characteristics under the ocean ambient noise, a technique for whitening the ambient noise spectrum using a metal baffle is proposed. Optimization of the array configuration is performed to achieve the directivity in the vertical and azimuthal directions. And the effects of the sonar dome shape and material on the structural vibration and sound scattering properties are studied. It is demonstrated that a robust hydrophone array, having a sensitivity deviation less than 4 dB over the frequency range of interest, can be obtained through the whitening of the ambient noise, the optimization of the array configuration, and the design of acoustically transparent sonar domes.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.5
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• pp.558-564
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• 2010

Cleaning up the landfill soil by phytoremediation in association with biomass production and utilization of biosolid as a soil amendment will be an attractive green technology. In order to examine this integrated green technology, in the current study of pot trial, heavy metal removal rate and biomass production were determined following cultivation of three different plant species in the landfill soil incorporated with biosolid at two different levels (25 ton $ha^{-1}$ and 50 ton $ha^{-1}$). Among the three plant species including Indian mustard (Brassica juncea), giant sunflower (Helianthus giganteus. L), and giant cane (Arundo donax. L), sunflower appeared to produce the largest biomass yield (19.2 ton $ha^{-1}$) and the produced amounts were magnificently increased with biosolid treatment compared to the control (no biosoild treatment). The increased production associated with biosolid treatment was common for other plant species and this was attributed to the biosolid originated nutrients as well as the improved soil physical properties due to the organic matter from biosolid. The elevated heavy metals in soil which was originated from the incorporated biosolid were Cu and Zn. Based on the phytoavailable amount of heavy metals from biosolid, the removed amount by plant shoots were 95% and 165% for Cu and Zn, respectively, when sunflower was grown. This indicated that mitigation of heavy metal accumulation in soils achieved by the removal of metal through sunflower cultivation enables the successive treatment of biosolid to soils. Moreover, sunflower showed heavy metal stabilization ability in the rhizosphere resulting in alleviation of metal release to ground water.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.6
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• pp.376-380
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• 2017

In this paper, we prepared a metal alloy resistor with stable thermal electro motive force (thermal EMF) as well as a low temperature coefficient of resistance (TCR) by adjusting the manganese proportion from 3 to 12 wt% in the Cu-Mn-Ni alloy. Composition of the fabricated metal alloy was investigated using energy dispersive X-ray (EDX) analysis. The TCR of each sample was measured as 44.56, 40.54, 35.60, and 31.56 ppm for Cu-3Mn-2Ni, Cu-5Mn-2Ni, Cu-10Mn-2Ni, and Cu-12Mn-2Ni, respectively. All the resistor samples were available for the F grade (${\pm}1%$ of the allowable error of resistance) high-precision resistor. All the samples satisfied the baseline of high thermal EMF (under 3 mV at $60^{\circ}C$); however, Cu-3Mn-2Ni and Cu-5Mn-2Ni satisfied the baseline of low thermal EMF (under 0.3 mV at $25^{\circ}C$). We were thus able to design and fabricate the metal alloy resistor of Cu-3Mn-2Ni and Cu-5Mn-2Ni to have low TCR and stable thermal EMF at the same time.

• Applied Chemistry for Engineering
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• v.26 no.6
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• pp.692-697
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• 2015

In this study, the reduction efficiencies of leachate heavy metal levels were investigated by adding $Al_2O_3$ and CaO to the bottom ash to observe their effects on the heavy metals leachate reduction efficiency. The ratio of $Al_2O_3$ and CaO contents were varied by 10~40% (W/W) alongside different curing time of 7 and 28 days. The reduction efficiencies of leachate heavy metal levels were estimated to be 69.3% for Cu and 52.1% for Pb during the curing time of 7 days. For the curing time of 28 days, the efficiencies changed to 85.2 and 100% for Cu and Pb, respectively. It was thus confirmed that the high reduction efficiency could be obtained as the curing time increased.

• Food Science and Preservation
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• v.15 no.3
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• pp.352-360
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• 2008

The extraction yield and storage stability of Codium fragile pigments extracted in acetone, ethanol or methanol were studied. Methanol was the most effective solvent for pigment extraction, providing an extraction yield of $25.0{\pm}2.10\;mg/g$ (my base). As shown by TLC and HPLC analysis, chlorophyll a(0.40 mg/g) and chlorophyll b(1.94 mg/g) were the major pigment components in dried Codium fragile. The total chlorophyll content of Codium fragile stored a 40C in light or dark conditions for 30 weeks remained at 23.2% and 58.4% respectively. The effect of metal ions ($Cu^{++}$, $Zn^{++}$, $Fe^{++}$ and $Mg^{++}$) on pigment stability was analyzed Among the four metal ions $Cu^{++}$ was the most effective stabilizer of Codium fragile pigments during storage, and $Zn^{++}$ ion was the second most effective. In the presence of 1 mM $Cu^{++}$, the total chlorophyll retained in Codium fragile stored at 40C in light or dark conditions was increased to 47.0% and 88.8% after 30 weeks storage, respectively. The optimum concentrations of $Zn^{++}$ and $Cu^{++}$ for pigment stabilization under dark conditions were 0.5 mM and 0.1 mM, respectively.