• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.298-302
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• 2005

This paper presents the protection effect of SPDs according to installation conditions. To develop the effective protection countermeasures of information and communication equipments against lightning surges, actual-sized experiments in relation to the protection effects on the installation positions of surge protective devices(SPDs), the length of branch circuit the materials and long of conduit were conducted. The best method for protecting the electronic equipments from surges is to install the SPD at the front point of the devices to be protected. The installation method of the metal conduit bonded with common ground conductor were more effective than that of the PVC conduit.

• Journal of the Korean Chemical Society
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• v.53 no.6
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• pp.793-804
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• 2009

In this study, high school students' perceptions of chemically ill-defined ‘heavy metals’ were examined through questionnaires. Nineteen classes of 11th graders (N = 611) were divided into two groups according to completion of 'Chemistry I', which were 10 science-classes and 9 liberal art-classes and compared each other. Three terms of students' cognition and definition, impact on the formation of their cognition, and their chemical knowledge of 'heavy metals' were analyzed by SPSS. The findings revealed that most of students recognized ‘the heavy metal’ as the metal which causes to be accumulated on any living thing and is hazardous in human body regardless of different major between liberal art and science. Mass media and school instruction were found to be the greatest impact on the formation of these cognitions. Especially, school instruction had more effects on students majoring in science than students majoring in liberal art, which bring the result that students in science-classes have more misconception about the definition of 'heavy metals' with human toxicant regardless of metal species and its content in human body and physical density due to the ill-defined terminology of the textbook than students in liberal art-classes do. It is interesting that students in science-classes understood hazard and chemical structure of 'heavy metals' better, while students in liberal art-classes answered the question better about hazardous properties of heavy metals.

• The Korean Journal of Ecology
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• v.23 no.6
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• pp.445-452
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• 2000

The effects of sludge and fertilizer application on germination and seedling growth of woody plants on heavy metal mine tailings were evaluated by greenhouse experiment. Two different mine tailings (Lead-zinc mine tailings from Kwangmyong, Kyonggi-do and tungsten mine tailings from Sangdong. Kangwon-do). four fertilizer treatments (N +P +K: 20, 40, 60, and 80 kg/m$^3$), and four sewage sludge treatments (5.5, 11, 22.5, and 45 Mg/m$^3$) were used in the experiment. Tested plants were Pinus densiflora, Larix leptolepis, Amorpha fruticosa, and Alnus hirsuta. There were three replicates for each treatment. In addition, vermiculite was used instead of mine tailings to determine the effect of physical amendments. Fifty seeds of a species were sown in a pot (upper diameter 13.5 cm, depth 10 cm) and seedling emergence were recorded daily for 30 days. The highest germination rate was 53% for all treatments. Germination rate of Larix leptolepis was lowest among the four species studied. One month later after seeding, seedlings were thinned and only 5 seedling were left in each pot, and fertilizer and sewage sludge were applied once again. Growth of seedlings were determined for 10 weeks since then. Most plants grew very poorly or died within 5 weeks on lead/zinc mine tailings from Kwangmyong. The analysis of heavy metal contents by the total dissolution method showed that heavy metals generally increased in the order of tungsten mine tailings from Sangdong < sewage sludge from Puchon < lead/zinc mine tailings from Kwangmyong. Growth of woody plants was improved significantly by the fertilizer treatments on tungsten mine tailings. In contrast. survival and growth of woody plants were not affected significantly by the sewage sludge treatment on both tailings. This study shows that fertilizer applied to established seeded stands may provide some benefits in terms of increased ground cover in the field. It is suggested that reclamation should be proceeded by the study of the physico-chemical and biological characteristics of mine tailings.

• 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.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.1
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• pp.65-72
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• 2013

This study was carried out to understand the long-term effects of organic waste treatments on the fate of heavy metals in soils originated from the organic wastes and consequent uptake of heavy metals by plant, together with examination of changes in soil properties and plant growth performance. In this study, the soils treated with three different organic wastes (municipal sewage sludge, alcohol fermentation processing sludge, pig manure compost) at three different rates (12.5, 25.0, 50.0 ton $ha^{-1}yr^{-1}$) for 7 years (1994 - 2000) were used. To see the long-term effect, plant growth study and soil examination were conducted twice in 2000 and 2010, respectively. There was no additional treatments of organic wastes for 10 years after the organic waste treatment for 7 years. Compared to plant growth examination conducted in 2000 using radish (Raphanus sativus cv. sodamaltari), it appeared that height, root length and diameter, fresh weight of radish grown in 2010 decreased in the plots treated with municipal sewage sludge and alcohol fermentation processing sludge and that the extent of decrease was higher with increase of sludge application rates. On the other hand, pig compost treatment increased plant height, root length and diameter, fresh weight with increasing application rates. Cu and Pb concentrations in radish root and leaves increased in 2010 compared to those in 2000 while Ni concentrations in root and leaves decreased. Zn concentration was increased only in the soils treated with pig manure compost. Multiple regression analysis among heavy metal species fractions in soils, soil pH, and metal concentrations in radish root and leaves indicated that the metal uptake by radish was governed mainly by the soil pH and subsequent increase of available heavy metal fractions in soils with organic waste treatments.

• Advances in environmental research
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• v.6 no.1
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• pp.15-23
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• 2017

Powdered marble wastes (PMW) generated by Utique marble cutting industries (North of Tunisia) with abundant amounts were used in this study as low-cost materials to investigate the stabilization of heavy metals (Pb, Zn, Fe) in sludge generated from a local Zn-Electroplating factory. Powdered marble wastes were evaluated by means of chemical fractions of heavy metals in sludge and concentrations of heavy metals in leachate from columns to determine their ability to stabilize heavy metals in contaminated sludge. Results indicated that chemical fractions of heavy metals in sludge were affected by application of the PMW mineral materials and pH, however, the effects varied with heavy metals. Application of the powdered marble wastes mineral materials reduced exchangeable metals in the sequence of Pb (60.5%)>Fe (40.5%)>Zn (30.1%). X-ray diffraction and hydro-geochemical transport code PHREEQC analysis were successfully carried out to get a better understanding of the mechanisms of reactive mineral phases involved in reduced exchangeable heavy metals in sludge after PMW material amendments. Therefore, metal immobilization using powdered marble wastes materials is an effective stabilization technique for industrial metallic hydroxide sludge.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.6
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• pp.491-495
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• 2014

Phytoremediation is a technology using plants and associated soil microbes to reduce the concentrations or toxic effects of contaminants in the environments. It is regarded as a cost-effective, efficient, eco-friendly, and solar-driven technology with good public acceptance. This study was conducted to find the plants accumulating heavy metals in soils contaminated with Cd and Pb. Experimental plots (plot size: $0.81m^2$) was artificially contaminated using a contaminated soil collected from a field in vicinity of Wondong mine (WD). Sunflower, corn and castor were tested for their potential to remove heavy metals from the contaminated soils. The results indicated that sunflower was most effective in accumulating heavy metals and thus remedying the soils among the three crops. Dry weight and heavy metal uptake of sunflower shoot differed with growth period. For example, the Cd content of shoots including leaf and stem were 0.31mg, 2.23 mg, and 0.96 mg per plot at 4, 8 and 12 weeks after planting in Cd4-WD treatment; in addition, the dry weight of the shoots in Cd8-WD treatment was reduced due to heavy metal toxicity. This experiment showed that sunflower absorbed Cd, Pb and Zn in their shoots up to 8 weeks of planting; thereafter heavy metals uptake was diminished. This implies that the efficiency of these plants in cleaning the contaminated soils may be high at the early stage of plant growth.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.3
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• pp.270-276
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• 2010

This study estimated the heavy metal concentrations in octopus (Octopus minor) and conducted a food safety assessment of octopus. Octopus, a benthic cephalopod, was collected from the Seosan intertidal zone on the west coast of Korea. The samples were digested with acids, and then the cadmium (Cd), copper (Cu), and zinc (Zn) contents were analyzed using inductively coupled plasma mass spectrometry (ICP-MS). The Cd, Cu, and Zn range of concentrations in octopus were 0.06-19 (mean 5.8), 44-1,463 (mean 354.8), and 76-929 (mean 247.9) mg/kg on a dry weight basis, respectively. The concentrations of heavy metals were higher in the internal organs than in the mantle. Of the three heavy metals, copper had the highest concentrations in the internal organs because of the existence of hemocyanin bound with copper in octopus blood, whereas zinc had the highest concentrations in the mantle. No relationship between the concentration of heavy metals and biological parameters (length, weight, and sex) was found. The ratios (I/M) of the heavy metal concentrations in internal organs and mantle were highest for cadmium, although cadmium had much lower concentrations in the internal organs compared with copper and zinc. Considering the provisional tolerable weekly intake (PTWI) of the three heavy metals and the average intake of octopus per day, all three elements should have no adverse effects on humans.

• Microbiology and Biotechnology Letters
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• v.36 no.2
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• pp.165-172
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• 2008

To find the optimum growth and metal removal condition of isolated strain LH2, effects of the environmental factors such as medium pH, growth temperature, and metal concentrations were investigated. Based on the 18S rDNA analysis, the isolated strain was identified to Exophiala sp. with 100% homology. Isolated strain Exophiala sp. LH2 showed maximum removal efficiency of metals at the shaking conditions of pH 7 and $25^{\circ}C$. When the concentration of metal was under 200ppm, the specific metal removal velocity at pH 7 increased from 0.01 to 4.43 mg-metal $L^{-1}{\cdot}d^{-1}{\cdot}mg{\cdot}DCW^{-1}$ as the concentration of metal increased from 10 ppm to 200 ppm. When 200 ppm of each metal was contained in the culture medium adjusted with pH 7, metal removal efficiencies Cr, Cu, Ni, Pb and Zn were 99.28%, 97.67%, 91.94%, 99.77%, 99.61%, respectively.

• Journal of fish pathology
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• v.23 no.2
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• pp.245-254
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• 2010

Effects of heavy metal ions on the gene expression of cytochrome P4501A (CYP1A) were examined in cultured eel hepatocytes. When the expression of CYP1A mRNA was measured by RT-PCR after incubation of eel hepatocytes with benzo[$\alpha$]pyrene (B[$\alpha$]P) at concentrations of 10-8~10-5 M, the CYP1A expression increased with B[$\alpha$]P treatment in a dose dependent manner, showing significant increase at concentrations more than 10-7 M. When the eel hepatocyte was treated with cadmium (10-6 and 10-5 M), the expression of CYP1A was inhibited and especially at higher concentration (10-5 M). The inhibition of CYP1A expression by cadmium was also observed in cells treated with B[$\alpha$]P. In another study, effects of heavy metal ions on the expression of CYP1A were examined in cultured hepatocytes isolated from eel which was treated previously with B[$\alpha$]P in vivo. Hepatocytes isolated from the liver of eel taken at 48 hours after injection of B[$\alpha$]P (10 mg/kg) were cultured for 2 days with cadmium, copper, lead or zinc (10-6 and 10-5 M). The expression of CYP1A was found to be suppressed by the metal ions compared with the control in which CYP1A was induced with previous treatment of B[$\alpha$]P in vivo. The present results may provide an important basic information for studying the effects of heavy metal ions on CYP1A expression in other species of fish and studying toxicological mechanisms of heavy metal ions in aquatic livings.