• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.1 no.1
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• pp.1-9
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• 1997

We investigated the depth profiles of heavy metals in the surface sediments at Heedong reservoir in Pusan. Sampling was done at the intervals of 50 m of drift along the water channel into the reservoir. All samples were analyzed with an ICP-AES. We determined the content of Zn, Pb, Cd, Mn, Cu, Cr, and Fe. The overall mean content of these heavy metals were observed to $(2.9\pm1.2){\times}10^{-3},\;(1.3\pm0.7){\times}10^{-3},$ $(1.9\pm2.1){\times}10^{-4},$ $(2.3\pm1.1){\times}10^{-2},\;(1.6\pm1.0){\times}10^{-3},\;and\;(4.5\pm2.6){\times}10^{-4}$ ppm/ppmFe, respectively excluding iron data. Mean contents of Cu show an increasing trend toward the surface of sediments, while those of Cd show a decreasing trend, and those of Pb and Cr are relatively stable. Comparing with the contents of heavy metals in soils at two sites of Kumjeong mountain, enrichment factors of heavy metals in the surface sediments were determined. Among heavy metals we investigated, copper showed the largest value of enrichment factor. Considering the maximum content of heavy metals in the surface sediment, the values of enrichment factors of Cu, Cd and Cr were significant, which were 22, 8.1 and 4.0, respectively. In leaching experiment, it appeared that Pb, Cd, Cr, and Fe in sediments were hardly leached out into water, We also examined the effect of pH on the content of heavy metals.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.2
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• pp.102-107
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• 2003

This study puts focus on the optimization of growth temperature of CIGS absorber layer which affects severely the performance of solar cells. The CIGS absorber layers were prepared by three-stage co-evaporation of metal elements in the order of In-Ga-Se. The effect of the growth temperature of 1st stage was found not to be so important, and 350$^{\circ}C$ to be the lowest optimum temperature. In the case of growth temperature at 2nd/3rd stage, the optimum temperature was revealed to be 550$^{\circ}C$. The XRD results of CIGS films showed a strong (112) preferred orientation and the Raman spectra of CIGS films showed only the Al mode peak at 173cm$\^$-1/. Scanning electron microscopy results revealed very small grains at 2nd/3rd stage growth temperature of 480$^{\circ}C$. At higher temperatures, the grain size increased together with a reduction in the number of the voids. The optimization of experimental parameters above mentioned, through the repeated fabrication and characterization of unit layers and devices, led to the highest conversion efficiency of 15.4% from CIGS-based thin film solar cell with a structure of Al/ZnO/CdS/CIGS/Mo/glass.

• Journal of the Korean Chemical Society
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• v.28 no.1
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• pp.41-46
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• 1984

To preconcentrate trace elements, microgram amounts of 5 heavy metals (Cu, Co, Ni, Zn and Cd) were precipitated with 8-hydroxyquinoline (oxine) and metal oxinates were extracted with stearic acid. And then each of the molten stearic acid extract with stearic acid. And then each of the molten stearic acid extract was poured into a glass ring and cooled for specimen preparation. The obtained specimens were analyzed by X-ray fluorescene spectrometry. And then conditions of precipitation formation and extraction, reproducibility, sensitivity and detection limit were observed. The relative standard deviation of specimen preparation was 1.0~5.7% and the detection limit was 5~$50{\mu}g$/100ml. The proposed preconcentration procedure exhibited a considerable inhancement and simplicity in preparing specimens.

• Journal of Environmental Science International
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• v.3 no.3
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• pp.197-207
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• 1994

Microorganisms capable of utilizing 2,4,5-trichlorophenoxyacetic acid(2,4,5-T) as sole carbon source were isolated from soil by enrichment culture. Among these strains, EL-O7IP had the highest biodegradability of 2,4,5-7, and according to its morphological and physiological characteristics, it was identified as Pseudomonas sp. This strain was resistant to rifampicin, streptomycin, ampicillin, kanamycin and such metal ions as $Zn^{2+}$, $Cu^{2+}$ Various compounds of chlorinated phenol and substrate analogs were more easily utilized than 2,4,5-7, but biodegradation rate for each compound was different. The strain easily utilized the compounds of chlorinated substituents on phenol in the order of ortho-, para-, and meta- position. The biodegradability of this strain was very stable. Key words : 2,4,5- trichlorophenoxyacetic acid, Pseudomonas sp .

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.10a
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• pp.292-300
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• 2001

The paper describes spectroscopic characteristics of plasma induces in the pulsed YAG laser welding of alloys containing a large amount of volatile elements. The authors have conducted the spectroscopic analyses of laser induced Al-Mg alloys plasma in the air and argon atmosphere. In the air environment, the identified spectra were atomic lines of Al, Mg, Cr, Mn, Cu, Fe and Zn, and singly ionized Mg lines, as well as the intense molecular spectra of A10 and Mg0 formed by chemical reactions of evaporated Al and Mg atoms from the pool surface with oxygen in the air. In argon atmosphere, Mg0 and AI0 spectra vanished, but AIH spectrum was detected. The hydrogen source was presumably hydrogen dissolved in the base metals, water absorbed on the surface oxide layer, or $H_2$ and $H_2O$ in the shielding gas. The resonant 1ines of Al and Mg were strongly self-absorbed, in particular, self-absorption of the Mg 1ine was predominant. These results show that the laser induced plasma was made of metal1ic vapor with relatively low temperature and high density.

• BMB Reports
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• v.28 no.2
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• pp.170-176
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• 1995

Rhodanese from mouse liver was purified to near homogeneity by ammonium sulfate precipitation, CM-Sephadex ion exchange, hydroxyapatite and Sephacryl S-200-HR gel filtration chromatographies with a purification of 776 folds. The molecular weight was determined by Sephadex G-150 gel filtration and found to be 34.8 KDa. SOS-PAGE showed molecular weight 34 KDa and two identical subunits splitting by aging for 3 weeks at $-70^{\circ}C$ the molecular weight of which was 17 KDa. The optimal pH of enzyme activity was 9.4 and the pI value of the enzyme was 6.6. Rhodanese showed the optimal reaction temperature of $25^{\circ}C$ and near linear increasing pattern until 10 min. incubation. $K_m$ values of rhodanese for KCN and $Na_{2}S_{2}O_{3}$ as substrates were 12.5 mM and 8.3 mM, respectively. Rhodanese activity was inhibited by more than 70% at a concentration of 100 ${\mu}M$ of $Ni^{2+}$, $Zn^{2+}$, $Cd^{2+}$, $Hg^{2+}$ and $Cu^{2+}$. Other metal ions, such as $Mn^{2+}$, $Mg^{2-}$, $Ca^{2+}$, and $Fe^{2+}$ showed no effect on rhodanese activity.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.05a
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• pp.46-51
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• 2000

Environmental quality regulations are used to establish the maximum permissible concentrations of heavy metals before a site can be deemed to be polluted or contaminated. This paper compares the results obtained by 0.IN HCl extraction and acid extraction method(HNO$_3$+HClO$_4$.HCl). The leaching efficiency of 0.1N HCl extraction is directly proportional to the final pH of leachate, due to the different solubilities of the heavy metals at different pH values, The severe differences between 0.1N HCl-extractable and total metal contents result mainly from the buffering effect of carbonates, present in sediment. samples. Application of sequential extraction experiments to some sediments collected from gully pot in Seoul illustrates a much stronger scavenging effect by Fe and Mn-hydroxides, carbonates and organic phases. As deduced from both sequential extraction and leaching experiments, the relative mobility of heavy metals is found to be: Mn>Zn>>Co>Cd>>Cu>Pb>Cr>Fe, in spite of large differences in heavy metal content and localization. Changes in the physicochemical environments (such as acidification) caused by a traffic accident may result in the severe environmental pollution of heavy metals of surrounding area( surface water and rivers).

• The Korean Journal of Quaternary Research
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• v.10 no.1
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• pp.27-52
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• 1996

금강 퇴적물의 지화학적 특성을 파악하기 위하여 상류에서 하류까지 21개의 표층 퇴적물을 채취하고 총금속(Al, Fe, Mn, Cr, Co, Ni, Cu, Zn, Pb) 입도별 금속 및 존재형태별 금속을 분석하였다. 또한 하천에서 연안역까지 미량금속의 공간적 변화를 보기 위해 부유물 을 일정 간격으로 채취하여 미량금속을 분석하였다. 퇴적물 중 미량 금속 함량을 평균 입도 와 밀접히 관계하여 변화하며 세립질실트 이하 부분에서 가장높은 함량을 보였고 이 높은 함량은 하천 부유물 중 금속 함량과 Mn을 제외하고 거의 유사한 수준이었다. Pb은 조립질 모래에서도 높은 함량을 보이는데 이는 조립질 모래에 많이 포함된 정장석에 의한 영향이 되고 세립질 실트에서의 높은 금속 함량은 세립한 중광물에 의한 영향이다. Mn과 Pb을 제 안한 금속들은 퇴적물 중 주로(70% 이상) 결정 격자와 관계하여 존재하는데 이는 퇴적물의 주구성 입도가 조립하여 금속이 풍부하고 세립한 중광 물에 의한 영향이 크기 때문이다. 하 천에서 염하구로 금속 함량이 급격히 감소하는데 이는 용존 $Mn^{+2}$이온이 $MnO_2$로 변화하는 산화반응과 하천구역에서의 퇴적 그리고 염하구에서 금속이 적어 진 입자(염하구 내에서 유기물 분해/용해로 만들어지거나 재부유 작요에 의한 조립질 물질) 와 하천 부유물과의 혼합작용에 의해 이루어진다.

• The Korean Journal of Ecology
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• v.25 no.6
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• pp.371-377
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• 2002

Leaves of two-week old seedlings of tomato (Lycopersicon esculentum) were treated with various concentrations (0, 0.2 and 0.4 $\mu$g/1) of 2,4,5-trichlorobiphenyl (PCB-29) and subsequent growth of seedlings, symptoms of oxidative stress and activities of antioxidant enzymes were investigated. Compared with the non-treated control, foliar application of PCB-29 decreased both biomass and superoxide ($O_2$) radical production but increased hydrogen peroxide production and lipid peroxidation such as malondialdehyde (MDA) formation with increased activities of superoxide dismutase (SOD), ascorbate peroxidase (APX) and guaiacol peroxidase (GPX). Further studies on the isozymes of SOD, peroxidase (POD) and APX showed that all three isozymes of SOD such as Mn-SOD, Fe-SOD and Cu/Zn-SOD, two among four isozymes of POD and all three isozymes of APX were selectively increased in response to PCB. Therefore, we suggest that a possible cause for the reduction of seedling growth by PCB exposure is the oxidative stress including over production of hydrogen peroxide and the selective expression of specific isozymes of some antioxidant enzymes.

• Journal of Environmental Science International
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• v.26 no.1
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• pp.119-131
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• 2017

This study evaluated the feasibility of recovering and recycling nitrogen (N) and phosphorus (P) from livestock excreta as struvite ($MgNH_4PO_4{\cdot}6H_2O$) in South Korea. Our experimental results showed that struvite precipitation was a very effective way to recover N and P from livestock excreta. Moreover, our study demonstrated that struvite precipitates from livestock excreta (SPL) contain higher concentrations of N, P, and magnesium (Mg) as compared to compost and liquid manure from livestock excreta. In addition, although SPL contain high concentrations of copper (Cu) and zinc (Zn), they meet the fertilizer criteria for concentrations of heavy metals. In South Korea, SPL cannot currently be used as a fertilizer due to legal constraints. Legal permission for SPL use would offer greater choice in livestock excreta management. In conclusion, recovery and recycling of N and P from livestock excreta as struvite can be an effective tool for managing nutrients in livestock excreta.