• Current Photovoltaic Research
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• v.6 no.1
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• pp.17-20
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• 2018

The dependency of the photovoltaic performance of p-/n-type silicon solar-cells on the metallic contaminant type (Fe, Cu, and Ni) and concentration was investigated. The minority-carrier recombination lifetime was degraded with increasing metallic contaminant concentration, however, the degradation sensitivity of recombination lifetime was lower at n-type than p-type silicon wafer, which means n-type silicon wafer have an immunity to the effect of metallic contamination. This is because heavy metal ions with positive charge have a much larger capture cross section of electron than hole, so that reaction with electrons occurs much more easily. The power conversion efficiency of n-type solar-cells was degraded by 9.73% when metallic impurities were introduced in the silicon bulk, which is lower degradation compared to p-type solar-cells (15.61% of efficiency degradation). Therefore, n-type silicon solar-cells have a potential to achieve high efficiency of the solar-cell in the future with a merit of immunity against metal contamination.

• Journal of Environmental Science International
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• v.14 no.6
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• pp.605-611
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• 2005

The aim of this study was to analyze the local distribution of the heavy metal concentration in Daegu and Ulsan which were divided into the residual areas, the traffic dense areas and the industrial areas. The Inductively Coupled Plasma(ICP) was used to analyze heavy metals, such as As, Cr, Hg, Zn, Cd, Pb, Cu and minor metals, such as Fe, Si, Mg, Ca, AI, Na, K. The results of this analysis showed that the content of heavy metals which was classified by districts in Daegu and Ulsan was the highest in the industrial areas followed by the traffic dense areas and the residual areas. Compared to the level of heavy metals of national and local soil survey network in 2003, contamination of heavy metals in Daegu was lower than national average. However, the content of Cd, As, Zn in Ulsan was respectively 13.38 times, 472 times and 2.65 times higher than national average contamination. In addition, compared to the soil pollution level of the environmental protection law, contamination of all areas in Daegu was lower. But the content of As at the industrial areas in Ulsan was 10.71 times higher than standard of soil pollution and 4.28 times higher than standard of measures against soil contamination.

• Journal of Food Hygiene and Safety
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• v.1 no.1
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• pp.51-56
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• 1986

In the particular area the heavy metal concentrations in the soil were determined and compared to the contents in vegetables which were grown on the soil. Simultaneously the degree of contamination was examined. Samples were collected from Chinese cabbage, radish and Altari-mu, together with the soil on which the three kinds of vegetables have grown. The sites of samples collection were Jinguan-sa(non-polluted area) and Sangaedong(polluted area). The contents of cadimium, copper, lead and zinc were determined by means of atomic absorption spectro-photometer. The results obtained were as follows; 1. In soils, the average contents of heavy metal in Jinguan-sa area (Cd; 0.15ppm, Cu; 0.15ppm, Zn; 11.5ppm) were lower than those in sangye-dong(Cd; 0.26ppm, Cu; 13.0ppm, Zn; 17.1ppm). 2. In vegetables, the average have metal contents in Jinguan-sa were cadmium; 0.11ppm, copper; 5.29ppm, zinc; 18.75ppm and the average contents in Sangye-dong were cadmium; 0.16ppm, copper; 6.64ppm, lead; 0.14ppm, zinc; 15.01ppm. 3. The contents of lead showed zero ppm in Jinguan-sa area(soil and vegetables). In vegetables difference in concentration of heavy metals was not observed between reclaimed area and non reclaimed area. Statistical analysis showed that no correlation in the heavy metal concentrations between those in soils and in vegetables.

• Korean Journal of Environmental Agriculture
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• v.21 no.3
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• pp.223-228
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• 2002

In addition to supplying the essential elements, Ca and S, phosphogypsum can have profound effect on both the physical and chemical properties of certain soils. However, no widespread use of by-product phosphogypsum will be made unless such uses pose no threat to the public health and soil contamination. In this study, the extractability of As, Cd, Cu, and Pb with water and DTPA solution from phosphogypsum samples of pH 3, 5, and 7 were investigated to estimate the availability of those metals. Contents of water extractable metals in ohosphogypsum were less than 5 mg/kg for all the heavy metals investigated. The extractability of metals in DTPA solution was not quite different but a little higher in comparison to the water extraction. And the extractability was decreased as the pH of phosphogypsum increased. In the phosphogypsum of pH 7, amounts of water extractable metals were nearly zero. There was no significant difference in the amount of extractable metals during the extraction period of 5 weeks. The length of extraction time did not affect heavy metal extractability. Therefore there may be small fractions of easily soluble or extractable forms of metals in the phosphogypsum and most of the metals would be present in very insoluble forms. These results suggest that the application of phosphogypsum at appropriate rates on agricultural lands appears of no concern in terms of hazardous element contamination in soil.

• Journal of Applied Biological Chemistry
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• v.57 no.2
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• pp.131-136
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• 2014

An attempt was made to assess metal ionic toxicity levels of different fishes in the polluted rivers viz., Buriganga and Turag. Fish samples collected from two polluted rivers were analyzed for the levels of metals such as Cd, Cr, Cu, Mn, Pb, and Zn in order to elucidate the status of these contaminants in fish meant for human consumption. The detected concentrations of Cr, Cu, Mn, and Zn ions in fish species collected from the polluted rivers were below the toxic levels and did not appear to pose a threat. Among the analyzed metals, Cd and Pb ions were detected above the permissible levels in liver and muscle tissues of stinging catfish (Heteropneustesfossilis), spotted snakehead (Channapunctata) and wallago (Wallagoattu) collected from the polluted rivers causing toxicity for human consumption. Stinging catfish (Heteropneustesfossilis) was the species found to highly bioaccumulate these metals. Fish species bioconcentrated appreciable amounts of Cd and Pb as toxic metals in the liver as compared to the muscle. Levels of these toxic metals varied depending on different tissues in fish species.

• Journal of the Korean earth science society
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• v.24 no.4
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• pp.346-360
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• 2003

In order to investigate the geochemical characteristics of surface sediments in streams of Gwangju City, sediment samples from the main stream of Yeongsan river, Hwangryong river, and Gwangjucheon in the city were collected and analyzed for grain size and metal and organic carbon contents. The sediment types of the streams widely vary from pebble to mud. The metal contents in the sediments from Yeongsan river and Hwangryong river are mainly dependent on the grain size of the sediments and the geology around the streams, while the sediments in Gwangiucheon are controlled by organic matter contents from the domestic sewage. The enrichment factor (Ef) and index of geoaccumulation (Igeo) representing the degree of metal contamination in the sediments are relatively low in the mainstream of Yeongsan river and Hwangryong river. However, those of Gwangjucheon show EF values of P=8.30, Cu=5.54, Zn=14.28 and Pb=7.41 and Igeo values of P=3.78, Cu=2.79, Zn=3.66 and Pb=1.59. The heavy metal contamination is especially significant near the area where the Seobangcheon and Donggyecheon branches of Gwanjucheon, join. Therefore, it is suggested that the metallic contaminations of these small streams are significantly influenced by the domestic sewage of the city.

• Journal of the Korean Society of Mineral and Energy Resources Engineers
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• v.55 no.6
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• pp.588-595
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• 2018

This study has focused on evaluation of heavy metal contamination in seepage from 23 mine waste dumping sites in Korea. Seepage samples from the sites were taken and analyzed for heavy metals. The maximum levels (mg/L) in the samples were Al 53.98, As 16.19, Cd 1.15 Cu 37.30, Fe 28.64, Mn 39.00, Ni 0.097, Pb 0.750, and Zn 80.18. Among the sites, six mines were selected as continuous monitoring sites. As results of three months' monitoring of the sites, over the water guidelines for As, Cd, Cu, Fe, Mn, Zn and Al in seepage samples were found at two abandoned Au-Ag mines, Cd, Mn, Zn and Al at two Pb-Zn mines, and As, Fe and Mn at two other Fe-W mines. Therefore, those six mines need continuous monitoring on contamination assessment of seepage due to mining activities.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.536-539
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• 2003

The Dongjung Au-Ag-Cu mine area was seriously contaminated with As and heavy metals-Cd, Cu, Hg, Mn, Pb and Zn etc. Those elements were highly accumulated in plants grown at farmland as well as farmland soil. Stream waters and groundwater which has been used as drinking water around the mine site contain high levels of heavy metals, especially As. As a result of human health risk assessment using EHS(Extraction of Heavy metals in Stomach and Small intestine) test for bioaccessible contents of heavy metals, there is a potential of cancer and adverse effects on human health for the residents of the mine area.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.404-408
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• 2003

In this study, we examined the influences of pH and total concentration on the speciation of heavy metals (Cd, Cu, Zn) in acid mine drainage. Their labile concentrations were analyzed by Anodic Stripping Voltammetry (ASV) at both natural pH and adjusted pHs (from 2 to 8). We obtained regression equations for predicting labile concentrations as a function of the water pH and contamination level (total dissolved metal concentration). Our data show that labile Cu depends on both the total concentration and pH, while labile Cd and Zn concentrations are controlled mainly by their total concentration rather than pH. Therefore, the pH variation of AMD may significantly change the toxicity and bioavailability especially of Cu, owing to its speciation change.

• Journal of Powder Materials
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• v.14 no.6
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• pp.410-414
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• 2007

Carbon contamination from the binder resin is an inherent problem with the metal powder injection molding process. Residual carbon in the W-Cu compacts has a strong impact on the thermal and electric properties. In this study, uncertainty was quantified to evaluate determination of carbon in a W-15%Cu MIM body by the combustition method. For a valid generalization about this evaluation, uncertainty scheme applied even to the repeatability as well as the uncertainty sources of each analyse step and quality appraisal sources. As a result, the concentration of carbon in the W-Cu part were measured as 0.062% with expanded uncertainty of 0.003% at 95% level. This evaluation example may be useful to uncertainty evaluation for other MIM products.