• 한국환경농학회지
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• 제33권2호
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• pp.129-133
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• 2014

BACKGROUND: This study was performed for selecting yeast mutants with a high tolerance for targeted metals, and determining whether yeasts strains tolerant to multiple heavy metals could be induced by sequential adaptations. METHODS AND RESULTS: A mutant yeast strain tolerant to the heavy metals cadmium (Cd), copper (Cu), nickel (Ni), and zinc (Zn) was selected by sequential elevated exposures to each metal with intermittent mutant isolation steps. A Cd-tolerant mutant was isolated by growing yeast cells in media containing $CdCl_2$ concentrations that were gradually increased to 1 mM. Then the Cd-tolerant mutant was gradually exposed to increasing levels of $CuCl_2$ in growth media until a concentration of 7 mM was reached, thus generating a strain tolerant to both Cd and Cu. In the subsequent steps, this mutant was exposed to $NiCl_2$ (up to 8 mM), and a resultant isolate was further exposed to $ZnCl_2$ (up to 60 mM), allowing the derivation of a yeast mutant that was simultaneously tolerant to Cd, Cu, Ni, and Zn. CONCLUSION: This method of inducing tolerance to multiple targeted heavy metals in yeast will be useful in the bioremediation of heavy metals.

• 한국해양환경ㆍ에너지학회지
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• 제15권4호
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• pp.302-313
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• 2012

마산만과 진해만 해저에서 각각 31개와 65개 표층퇴적물을 채취하여 중금속(Al, Fe, Mn, Cr, Cu, Ni, Zn, Pb, As, Cd)을 분석하였다. 중금속 함량은 우리나라 주변의 만 및 하구 퇴적물에 비해 마산만에서 Fe, Cr, Cu, Zn, Pb, Cd, As 등이 높았고 진해만에서 Mn이 높았다. Cu, Zn, Pb, Cd, As는 항구 및 산업시설이 위치한 마산만 해안에서 매우 뚜렷한 증가를 보였으며 공간분포를 통한 오염물질의 근원지 추정이 가능하였다. 오염에 의한 중금속 농축은 지각의 함량을 배경농도로 한 농축비에 근거할 때 진해만은 국지적으로, 반면에 마산만은 넓은 지역에 걸쳐 활발히 진행된 것으로 확인되었으며 특히 Cu, Zn, Pb 및 Cd의 농축비가 대비되었다. As, Cd, Cr, Cu, Pb, Ni, Zn 함량을 중금속 환경기준에 적용한 결과 진해만 시료의 일부와 마산만 시료의 거의 대부분이 주의기준(NOAA ERL, EC TEL, ANZECC ISQG-low, Hong Kong ISQV-low)을 초과하였으며, Cu 및 Zn 함량은 일부 마산만 시료에서 관리기준(NOAA ERM, EC PEL, ANZECC ISQG-high, Hong Kong ISQV-high)을 초과하였다. $I_{geo}$ 값에 근거한 마산만의 중금속 오염은 Fe, Mn, Cr, Ni는 우려할 만한 수준이 아닌 반면 Cu, Zn, Pb는 강한 오염단계에 직면해 있거나 진입해 있으며, Cd는 시료의 87.1%가 강한 오염단계 이상의 심화된 오염상태로 파악되었다.

• 대한화학회지
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• 제41권10호
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• pp.561-565
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• 1997

• Journal of Ecology and Environment
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• 제30권1호
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• pp.81-86
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• 2007

Human activities have enhanced the influx of heavy metals to aquatic ecosystem and hanged the abiotic environment such as the sediments supporting benthic organisms. The levels of heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) in the benthic gastropod Oxyloma hirasei and the sediments around their habitat were investigated to examine heavy metal levels and the potential of the gastropod as a bioindicator. We detected different levels of heavy metals in the sediments of two wetland areas, Upo and Mokpo, in the relatively well-conserved Upo wetland, Ramsar Convention Area. Oxyloma hirasei had higher concentrations of heavy metals except Cr and Ni in their soft tissues than in their shells (Cd: $2.10{\sim}3.16$, Cu: $19.73{\sim}28.66$, Pb: $0.67{\sim}1.17$, Zn: $216.1{\sim}285.7\;{\mu}g/g$ dry weight in the soft tissues; Cr: $1.19{\sim}2.58$, Ni: $0.47{\sim}1.16\;{\mu}g/g$ dry weight in the shells). Differences in the Cd, Cu, Ni and Pb concentrations in O. hirasei soft tissues reflected differences in heavy metal concentrations in the sediments at the sampling sites. The coefficients of variation for Cd, Cu and Pb were lower than those for other metals in the soft tissues. Levels of Cd in the tissues of O. hirasei were the highest among the metals examined in this study. Therefore, the soft tissue of O. hirasei appears to be a promising bioindicator particularly for Cd.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.551-554
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• 2002

As a general rule, the brazing process between cemented carbides and steel used by Silver (Ag) type brazing filler. The composition of Ag type filler were used Ag-Cu-Zn-Cd type filler mainly. But, the demand of Cadmium (Cd)-free in Ag type filler was raised recently. The reason why Cd-free in Ag brazing filler were occupied to vaporize as a CdO$_2$ when brazing process, because of Cd element was almost low boiling point of all Ag type filler elements. And, CdO$_2$ was a very harmful element for the human body. This experiment was developed Cd-freeing on Ag type filler that was used Indium (In) instead of Cd element. In this experiment, there were changed from 0 to 5% In addition in Ag brazing filler and investigated to most effective percentage of Indium. As a result, the change of In addition instead of Cd, there was a very useful element and obtained same property only 3% In added specimens compared to Cd 19% added specimens. These specimens were obtained same or more deflective strength. In this case, there were obtained 70 MPa over strength and wide brazing temperature range 650-800 C. A factor of deflective strength were influenced by composition and the shape of $\beta$ phase and between $\beta$ phase and cemented carbides interface. Indium element presented as $\alpha$ phase and non-effective factor directly, but it's occupied to solid solution hardening as a phase. $\beta$ phase were composed 84-94% Cu-Ni-Zn elements mainly. Especially, the presence of Ni element in interface was a very important factor. Influence of condensed Ni element in interface layer was increased the ductility and strength of brazing layer. Therefore, these 3% In added Ag type filler were caused to obtain a high brazing strength.

• Applied Biological Chemistry
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• 제20권3호
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• pp.300-309
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• 1977

The information related to the heavy metal pollution in the environment was obtained from studies on the effects of pH, phosphate and soil properties on the adsorption of metal ions (Cd, Cu, Ni, and Zn) by soils. Three soil materials; soil 1 with low CEC (8.2 me/100g) and low organic carbon content (0.34%); soil 2 with high CEC (36.4 me/100g) and low organic carbon content (1.8%) and soil 3 with high CEC (49.9 me/100g) and high organic carbon content (14.7%) were used. Soils were adjusted to several pH's and equilibrated with metal ion mixtures of 4 different concentrations, each having equal equivalents of each metal ion (0.63, 1.88, 3.12 and 4.38 micromoles per one gram soil with and without 10 micromoles of phosphate per one gram soil). Reported here are the results of the equilibrium study on soil I. The rest of the results on soil 2 and soil 3 will be repoted subsequeutly. Generally higher metal ion concentration solution resulted in higher final metal ion concentrations in the equilibrated solution and phosphate had minimal effect except it tended to enhance removal of cadmium and zinc from equilibrated solutions while it tended to decrease the removal of copper and nickel. In soil 1, percentages of added metal ions removed at pH 5.10 were; Cu 97, Ni 69, Cd 63, and Zn 55, while increasing pH to 6.40, they were increased to Cu 90.9, Zn 99, Ni 96, and Cd 92 per As initial metal ion concentration increased, final metal ion concentrations in the equilibrated solution showed a relationship with pH of the system as they fit to the equation $p[M^{++}]=a$ pH+b where $p[M^{++}]=-log$[metal ion concentration in Mol/liter]. The magnitude of pH and soil effects were reflected in slope (a) of the equation, and were different among metal ions and soils. Slopes (a) for metal ions in the aqueous system are all 2. In soil 1 they were; Zn 1.23, Cu 0.99, Ni 0.69 and Cd 0.59 at highest concentration. The adsorption of Cd, Ni, and Zn in soil 1 could be represented by the Iangmuir isotherm. However, construction of the Iangmuir isotherm required the correction for pH differences.

• 한국해양학회지:바다
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• 제7권4호
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• pp.226-234
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• 2002

퇴적물 내 황화물(acid volatile sulfide, AVS)이 저서 생물의 금속 생물 축적 및 독성 반응에 어떠한 영향을 미치는 지를 이해하기 위해서 해양 다모류인 Neanthes arenaceodentata를 이용한 퇴적물 노출실험을 수행하였다. 이를 위해서 세 개의 다른 AVS 농도군에 대조구를 포함한 다섯 개의 농도 구배로 Cd, Ni, Zn를 오염시킨 퇴적물에서 N. arenaceodentata를 20일간 배양한 후 실험생물의 체내 금속 축적량과 그에 따른 사망률 및 성장률을 조사하였다. N. arenaceodentata에 의한 금속의 생물축적은 Cd과 Zn의 경우 AVS 농도의 영향을 받아서 해수(overlying water, OW)내 용존 금속 농도에 비례해서 증가했다. Ni은 AVS농도에 영향을 받지 않고 퇴적물 내 금속(simultaneously extracted metals. SEM)농도에 비례해서 증가했다. N. arenaceodentata의 사망과 성장률 저해현상은 SEM과 AVS 간의 몰농도차가 영보다 큰 조건(［SEM-AVS］>0)에서만 관찰되었는데 용존 Zn에 의한 결과로 추정되었다. OW-Zn의 20-d LC50값은 9.3(8.0$\pm$11.0) $\mu$M이었다. 사망률에 대한 체내 Zn 농도의 최소영향농도(LOEC)는 7.8 $\mu$mol/g이었고, 최대무영향농도(NOEC)는 6.2$\mu$mol/g이었다. 성장률 저해에 대한 체내 Zn 농도의 LOEC는 5.9$\mu$mol/g이었고, NOEC은5.1 $\mu$mol/g토이었다. 본 실험에서는 실험실 조건에서 인위적으로 오염시킨 퇴적물 내 Zn의 입자상 Zn 농도와 용존 Zn농도의 비 (K$_{d}$ )가 현장 퇴적물에 비해서 10배 정도 감소함으로써 결국 용존 Zn에 의한 독성이 과대평가된 것으로 보인다.

• 한국재료학회지
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• 제11권10호
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• pp.859-862
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• 2001

The crystal structure and magnetic properties of the $Ni_{1-x} Cd_xFeAlO_4$(0$\leq$x$\leq$0.5) have been investigated by means of X-ray diffractometry and Mossbauer spectroscopy. The samples($0\leq$x$\leq$0.5) have been prepared by the ceramic sintering method. The X-ray diffraction pattern shows that the crystal structure of the samples is a cubic spinel type. The lattice constant has been found by extrapolation using the Nelson- Riley function and it increases slightly from $8.321{\AA}$ to $8.410{\AA}$ with Cd concentration. The Mossbauer spectra for x<0.4 show a superposition of two sextets and a paramagnetic doublet at room temperature. The cation distribution for x=0 was determined to be $[Fe_{0.75}Al_{0.25}]^A[NiFe_{0.25}Al_{0.75}^BO_4$. The superparamagnetic doublet for x< 0.4 seems to be due to A1 ion in tetrahedral site by the superparamagnetic clustering effect.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2006년도 총회 및 춘계학술발표회
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• pp.242-246
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• 2006

Background level of heavy metals In soils (316 points by 15 classifications of land use) was investigated by two test methods, 0.1N HCl(1N HCl for As) extraction and aqua regia extraction methods. The average concentrations of aqua regia extractable heavy metals in soil(n=316) was 6.24(As), 0.25(Cd), 37.99(Cr), 24.10(Cu), 0.04(Hg), 25.68(Pb), 22.59(Ni), 106.11(Zn) mg/kg, respectively. Also the average concentrations of 0.1N HCl extractable heavy metals was 0.06(As), 0.08(Cd), 0.27(Cr), 3.78(Cu), 4.02(Pb), 12.5(Zn), 0.58(Ni) mg/kg, respectively. The ratio of soluble contents and total contents were 2.6%(As), 32.7%(Cd), 0.7%(Cr), 15.7%(Cu), 15.7%(Pb), 2.6%(Ni), 11.8%(Zn), and the correlation coefficient of soluble contents and total contents were 0.26(As), 0.27(Cd), 0.22(Cr), 0.57(Cu), 0.42(Pb), 0.23(Ni), 0.72(Zn).

• 한국환경과학회지
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• 제26권7호
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• pp.847-858
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• 2017

For 26 soil series distributed more than 1% among 63 soil series in Jeju Island, natural uncultivated soil samples were collected. For these soils, the chemical speciation of eight heavy metals (Cd, Cr, Cu, Mn, Ni, Pb, V, and Zn) was examined. Further, the Plant Bioavailability (PB) and Mobility Factor (MF) of these heavy metals were evaluated using Tessier's 5-step sequential extraction method (exchangeable, carbonate, reducible (bound to Fe/Mn oxides), oxidizable (bound to organic matter), and residual fraction). The main form present was residual fraction for Cd and Zn; residual and oxidizable fractions for Cr, Cu, Ni, and Pb; reducible fraction for Mn; and carbonate fraction for V. The average plant availability and average mobility factor were found to be V (57.37%) > Zn (12.49%) > Cd (11.76%) > Cu (11.19%) > Pb (9.37%) > Cr (9.09%) > Mn (3.13%) > Ni (2.63%), and Mn (61.04%) > V (59.94%) > Zn (31.54%) > Cd (17.65%) > Cr (15.66%) > Ni (13.89%) > Pb (13.80%) > Cu (13.53%), respectively.