• Journal of the Mineralogical Society of Korea
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• v.29 no.3
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• pp.89-101
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• 2016

This study investigated spectral characteristics of heavy metal contaminated soil samples in the vicinity of abandoned Boksu mine. Heavy metal concentrations including arsenic, lead, zinc, copper and cadmium were analyzed by XRF analysis. As a result, all of the soil samples excluding control sample were over-contaminated based on the counter measure standard. The XRD results revealed that quartz, kaolinite and smectite were detected for all of the soil samples and heavy metals in soil were adsorbed on clay minerals such as kaolinite and smectite. The spectral analyses confirmed that spectral reflectance of near-infrared and shorter portion of shortwave-infrared spectrum decreases as heavy metal concentration increases. Moreover, absorption depths at 2312 nm and 2380 nm, the absorption features of clay minerals, decreases with higher heavy metal concentration indicating adsorption of heavy metal ions with clay minerals. It indicates that spectral features and heavy metal contamination of soil samples have high correlations.

• Korean Journal of Veterinary Research
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• v.36 no.3
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• pp.709-718
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• 1996

This experiment was carried out to clarify the effect of lead poisoning on the lead and essential trace elements homeostasis of tissues in rats. Fifty female Wistar rats, 7 weeks old, were divided into four experimental groups(B, C, D, and E) and a control(A). The four experimental groups received diets contaminated artificially with 10 (B group), 100 (C group), 1,000 (D group) and 5,000 (E group) ${\mu}g/g$ of lead as lead acetate, respectively. The control group received normal diet. Rats were necropsied on the 4th or 8th week of experimental periods and heart, liver, spleen, kidney, muscle, lung and hair were taken. The tissues were analysed for lead, copper, zinc, iron and calcium content by atomic absorption spectrophotometry. From these experiments following results ware obtained ; In C group, lead content of the heart, liver, kidney and hair were significantly increased both on the 4th and 8th week of experiment. In D and E group, lead content of all tissues including heart, liver, spleen, kidney, muscle, hair and lung were significantly increased in accordance with the lead contamination both on the 4th and 8th week of experiment. In C group, copper content of tissues were significantly increased in the heart, liver, kidney and lung on the 4th week and all tissues on the 8th week of experimental periods. In D and E group, copper content of the liver were significantly increased both on the 4th and 8th week of experiment. But the copper content of tissues were gradually decreased compared with C group in accordance with the lead contamination. Especially the content in spleen, heart or kidney were significantly decreased compared with the control group. The zinc content of kidney, heart, or spleen were decreased in D and E groups whereas the iron and calcium content showed no significant change.

• Journal of Wetlands Research
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• v.13 no.2
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• pp.243-263
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• 2011

In order to understand the sedimentary environment of the southern intertidal zone of Shihwa Lake, west coast of Gyeonggi-do, 10 surface and 2 core sediment samples were analysed for grain size, water content, AVS (Acid Volatile Sulfide), TOC (Total Organic Carbon), concentrations of metals (Al, Fe, Mn, Cu, As, Pb, Zn, Ni, Cd, and Cr). The surface sediments are generally poorly sorted (0.60~2.31 ${\phi}$) sandy Silt, slightly gravelly muddy Sand, silty Sand, Sand with mean grain size of 2.95 to 6.00 ${\phi}$. The sediments contain Al (1.54%), Fe (1.75%), Cu (9.1ppm), As (1.1ppm), Pb (18.8 ppm), Ni (11.0 ppm), Cd (0.02 ppm), and Cr (30.1 ppm) on the average. Heavy metals are concentrated less than ERL (Effect Range-Low), verified by NOAA (National Oceanic and Atmospheric Administration). In the core sediments, they are also less than the ERL. Based on the uniform vertical distribution of excess radioactivity of $^{210}Pb$, the core sediments seen to have been actively mixed biologically or rapidly deposited after the construction of Shi-Hwa Seawall. The 'enrichment factor' of metals, normalized to Al, shows that the upper sediments of 35 cm in depth are more polluted. infect was significant in 2 core sediment samples in 35 cm below layer.

• Korean Journal of Environmental Agriculture
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• v.34 no.4
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• pp.282-287
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• 2015

BACKGROUND: The current study was carried out to investigate Cd, Hg, Pb and As contaminations in 222 commercial medicinal plants and to estimate the potential health risk through dietary intake of commercial medicinal plants in Korea.METHODS AND RESULTS: The Cd, Hg, Pb, and As in medicinal plants were analyzed by ICP/MS and mercury analyzer.The potential health risk was estimated using risk assessment tools. Total amount of Cd in medicinal plants with 29% samples exceeded the standard limit legislated in 'Pharmaceutical Affairs Act' while all plant samples were lower than the standard limit value for As, Hg, and Pb. However, when applying the standard limit for root vegetable (fresh weight) in the Food Sanitation Act, four samples exceeded the standard limit of Pb. For health risk assessment, the values of cancer risk probability were 0.3~5.9×10^-7which were less than the acceptable cancer risk of 10^-6~10^-4for regulatory purpose. Also, Hazard quotientvalues were lower than 1.0.CONCLUSION: Therefore, these results demonstrated that human exposure to Cd, Hg, Pb, and As through dietary intake of commercial medicinal plants might notcause adverse health effects although some medicinal plants were higher than the standard limit values for Cd and Pb.

• Applied Biological Chemistry
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• v.42 no.1
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• pp.73-78
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• 1999

Acid mine drainage (AMD) results from sulfuric acid produced by the oxidation of pyrite, and contains large amounts of toxic elements. In the neutralization of AMD, iron and aluminum hydroxides are the major precipitates and those two can be separated with two-phase neutralization. In this study, removal of toxic elements by the two phases of neutralization was investigated using an AMD collected from the abandoned antimony mine in Gachang, Taegu. Contents of As, Cd, Cu, Mn, Pb and Zn in the AMD were higher than the criteria of river water quality or permissible waste water discharge. In the first phase, the AMD was neutralized to several % (25, 50, 75, 100, and 125) of $Fe(OH)_3$ equivalence point with solid $Ca(OH)_2$. In the second phase, the supernatant of the first phase neutralization was titrated to pH 7.5. After neutralization of the AMD to 100% of the $Fe(OH)_3$, equivalence point, most of Fe and Pb were removed but levels of As, Cd, Cu, Ni, Mn, and Zn were not reduced in the supernatant solution. In the second phase neutralization, levels of those toxic elements in the supernatants dropped below the wastewater discharge or river water quality criteria. This result suggests that the precipitate formed in the first phase of the neutralization process may be disposed without any special cares. Thus the two-phase neutralization scheme can reduce the cost of disposing precipitates containing toxic metals in comparison with the monophase neutralization scheme.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.28 no.3
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• pp.130-134
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• 2018

In the past few years, various solder compositions have been a representative material to electronic packages and surface mount technology industries as a replacement of Pb-base solder alloy. Therefore, extensive studies on process and/or reliability related with the low Ag composition have been reported because of recent rapid rise in Ag price. In this study, Sn-3.0Ag-0.5Cu, Sn-0.7Cu and Sn-0.3Ag-0.5Cu solder bar samples were fabricated by melting of Sn, Ag and Cu metal powders. Crystal structure and element concentration were analyzed by XRD, XRF, optical microscope, FE-SEM and EDS. The fabricated solder samples were composed of ${\beta}-Sn$, ${\varepsilon}-Ag_3Sn$ and ${\eta}-Cu_6Sn_5$ phases.

• Journal of the Mineralogical Society of Korea
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• v.22 no.4
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• pp.297-305
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• 2009

Ores of the Jeonnam pyrophyllite province mainly consist of not only pyrophyllite but also kaolinite, and they usually contain minor amounts of muscovite and quartz. We usually call them as porcelaneous stones which usually show lower grade characteristics in the viewpoint of Korean nonmetallic industries. Mineralogical studies for the ores and their intimate formations revealed that another kind of clay minerals could have been produced from the volcanic sediments with similar ages and compositions. Corundum is commoner than the diaspore in the pyrophyllite deposits, and so diaspore can be regarded as one of temporary minerals from which corundum would be finally formed. Kaolinite deposits contain neither diaspore nor corundum, but alunites produced by an advanced argillic alteration are often observed in the upper portions of the kaolin ores. The lowest formation interbedded with pyrophyllite and/or kaolinite ores usually contain purple tuff bed on the uppermost part, and in ascending order, siliceous formation, fine ash tuff and lapillistone are found in the study areas. As ages are becoming younger, amounts of pyrophyllite and kaolinite are radically decreased, or disappeared completely. On the other hand, content of muscovite is slightly increased, and those of plagioclase feldspars and quartz are found to have been preserved from the original rocks during alteration process. Most of ore bodies show rather well bedded formations which are easily discernable in the outcrops, but more effective discremination is desirable where rather massive ores exist. Siliceous beds and purple tuff ones on the upper part of ore bodies would be useful as marker horizons or key beds which have distinct lithologies and extensions.

• Resources Recycling
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• v.14 no.5 s.67
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• pp.45-53
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• 2005

Electro-generated chlorine leaching of waste printed circuit boards was investigated in hydrochloric acid solutions. Non-magnetic component of $0.6{\sim}1.2mm$ was prepared by grinding, magnetic separation, and sieving. The non-magnetic component of pulverized printed circuit board contained about 45% of metal component, in which copper was about 83.6%. The leaching rate of copper was greatly affected by current density and agitation speed. The leaching of copper up to 98% was achieved at $20mA/cm^2$, $50^{\circ}C$, 180 minutes, and 600 rpm in 1M HCl solutions. Increasing agitation and lowering current density enhanced utilization efficiency of electro-generated chlorine. Leaching of copper was suppressed at the initial stage, while the minor metal elements, such as aluminum, lead, and tin, were dominantly leached out.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1080-1084
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• 2011

Predictive model for estimating total contents of cadmium (Cd) and lead (Pb) was developed by stepwise multiple-regression analysis using chemical properties and extractable contents of metal in paddy soil adjacent to abandoned mines in 2009 and 2010. Soil properties, e.g. pH, electrical conductivity (EC), organic matter (OM), available phosphorus ($P_2O_5$), and exchangeable cations (i.e. Ca, Na, K, Mg) were measured. Total contents of Cd and Pb as well as extractable contents of metals were analyzed by ICP-OES. Results showed that the total and extractable contents were estimated to be 3.55 and $0.27mg\;kg^{-1}$ in Cd and 83.38 and $24.32mg\;kg^{-1}$ in Pb on the average. From stepwise analysis, it was found that the contents of extractable Cd, Zn, Cu, as well as exchangeable Na were significantly influenced on estimation of the total contents of Cd in soil. Moreover, it also showed that the contents of extractable Pb, Zn, and Cu significantly affected estimation of the total contents of Pb in soil. More significant relationship between estimated and measured value in total contents of Pb was observed than those of Cd ($R^2$=0.87, p<0.0001). This demonstrates that extractable contents of metal are influenced more on estimation of total contents of Cd and Pb in soil than soil properties.

• Journal of Mushroom
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• v.18 no.4
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• pp.387-392
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• 2020

Eight dried ear mushroom products (three domestic and five Chinese products) distributed in Korea were analyzed for 321 residual pesticides, 7 heavy metals, and 3 types of radioactivity. Residual pesticides in the domestic products were not detected. However, chlorpyrifos, isoprocarb, mepiquat chloride, and carbendazim were detected in four Chinese products, all of which were below the allowable residual limit. Among the detected pesticide ingredients, only the residue for mepiquat chloride has been established to be present in ear mushrooms. In the heavy metal test, trace amounts of heavy metals were detected in all samples. However, none of the samples exceeded the allowable residual limits, except for one domestic sample that exceeded the standard value of 0.3 mg/kg for lead. Radioactivity tests confirmed that levels were below the minimal detectable activity value in all samples.