• Economic and Environmental Geology
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• v.31 no.4
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• pp.297-310
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• 1998

Geochemical characteristics of environmental toxic elements at the Narim mine area were investigated on the basis of major, minor, rare earth element geochemistry and mineralogy. Ratios of $Al_2O_3/Na_2O$ and $K_2O/Na_2O$ in soils and sediments range from 11.57 to 22.21 and from 1.86 to 3.93, and are partly negative and positive correlation against $SiO_2/Al_2O_3$ (3.41 to 4.78), respectively. These suggested that sediment source of host granitic gneiss could be due to rocks of high grade metamorphism originated by sedimentary rocks. Characteristics of some trace and rare earth elements of V/Ni (0.33 to 1.95), Ni/Co (2.00 to 6.50), Zr/Hf (11.27 to 53.10), La/Ce (0.44 to 0.55), Th/Yb (4.07 to 7.14), La/Th (2.35 to 3.93), $La_N/Yb_N$ (6.58 to 13.67), Co/Th (0.63 to 2.68), La/Sc (3.29 to 5.94) and Sc/Th (0.49 to 1.00) are revealed a narrow range and homogeneous compositions may be explained by simple source lithology. Major elements in all samples are enriched $Al_2O_3$, MgO, $TiO_2$ and LOI, especially $Fe_2O_3$ (mean=7.36 wt.%) in sediments than the composition of host granitic gneiss. The average enrichment indices of major and rare earth elements from the mining drainage are 2.05 and 2.91 of the sediments and are 2.02 and 2.60 of the soils, normalizing by composition of host granitic gneiss, respectively. Average composition (ppm) of minor and/or environmental toxic elements in sediments and soils are Ag=14 and 1, As=199 and 14, Cd=22 and 1, Cu=215 and 42, Pb=1770 and 65, Sb=18 and 3, Zn=3333 and 170, respectively, and extremely high concentrations are found in the subsurface sediments near the ore dump. Environmental toxic elements were strongly enriched in all samples, especially As, Cd, Cu, Pb, Sb and Zn. The level of enrichment was very severe in mining drainage sediments, while it was not so great in the soils. Based on the EPA value, enrichment index of toxic elements is 8.63 of mining drainage sediments and 0.54 of soils on the mining drainage. Mineral composition of soils and sediments near the mining area were partly variable being composed of quartz, mica, feldspar, amphibole, chlorite and clay minerals. From the gravity separated mineralogy, soils and sediments are composed of some pyrite, arsenopyrite, chalcopyrite, sphalerite, galena, goethite and various hydroxide minerals.

• Analytical Science and Technology
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• v.24 no.4
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• pp.310-318
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• 2011

The collection of atmospheric $PM_{10}$ and $PM_{2.5}$ particle samples was made at Gosan site of Jeju Island, which is one of the most representative background sites in Korea. Their chemical compositions have been analyzed to explore the pollution characteristics and emission sources. The mass concentrations of $PM_{10}$ and $PM_{2.5}$ particles were $37.6{\pm}20.1$ and $22.9{\pm}14.3{\mu}g/m^3$, respectively, with the content of $PM_{2.5}$ to $PM_{10}$ as 61%. The $PM_{2.5}/PM_{10}$ ratios of nss-$SO_4^{2-}$, $NO_3^-$, and $NH_4^+$ were 0.94, 0.56, 1.02, respectively, indicating that these components were distributed mostly in the fine fractions. Based on the factor analysis, it was found that the compositions of fine particles were mainly influenced by anthropogenic sources, followed by soil or marine sources. The results of the backward trajectory analysis indicate that the concentrations of nss-$SO_4^{2-}$, $NO_3^-$, $NH_4^+$, nss-$Ca^{2+}$, and Pb were high when the air parcels moved from the China continent, while relatively low with the air parcels coming from North Pacific Ocean and/or East Sea.

• Journal of the Microelectronics and Packaging Society
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• v.22 no.2
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• pp.47-53
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• 2015

The effects of electroless nickel immersion gold (ENIG) and organic solderability preservative (OSP) surface finishes on the in-situ intermetallics reaction and the electromigration (EM) reliability of Sn-3.0Ag-0.5Cu (SAC305) solder bump were systematically investigated. After as-bonded, $(Cu,Ni)_6Sn_5$ intermetallic compound (IMC) was formed at the interface of the ENIG surface finish at solder top side, while at the OSP surface finish at solder bottom side,$ Cu_6Sn_5$ and $Cu_3Sn$ IMCs were formed. Mean time to failure on SAC305 solder bump at $130^{\circ}C$ with a current density of $5.0{\times}10^3A/cm^2$ was 78.7 hrs. EM open failure was observed at bottom OSP surface finish by fast consumption of Cu atoms when electrons flow from bottom Cu substrate to solder. In-situ scanning electron microscope analysis showed that IMC growth rate of ENIG surface finish was much lower than that of the OSP surface finish. Therefore, EM reliability of ENIG surface finish was higher than that of OSP surface finish due to its superior barrier stability to IMC reaction.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.11
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• pp.1422-1426
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• 2008

The purpose of this study was to test characteristics between normal and autistic children via comparison of nutrient intakes, hair mineral, blood free radical, and serotonin contents. A total of 50 children aged 3-9 were divided into two main groups of normal control children (n=22) and autistic children (n=28) tested by child psychiatrist. The nutrient intakes by 24-hour recall method were no significantly different between the two groups. The concentrations of toxic mineral, such as cadmium (Cd) and lead (Pb) in hair of autistic children were significantly higher, while concentration of antioxidant mineral (Cu, Zn, Fe) was lower than that of normal children. The autistic children had significantly higher concentrations of blood free radical than that of normal children. No significant difference was observed in serotonin concentration between the two groups. Our results suggest a possible role of increased toxic mineral and free radical, both of which may be relevant to the pathophysiology of autism in children with developmental delay.

• Korean Journal of Environmental Agriculture
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• v.2 no.2
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• pp.90-97
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• 1983

Water pollution status of the sewage in Jinju City was investigated to provide the basic information for the conservation of the Nam River. Physicochemical characteristics of the sewage were examined at five sites of sewage ditches, Jinyang Lake and Nam River. The results are as follows; 1) Average value of analyzed components of the sewage at five sampling sites were pH 7.1, DO 2.3 ppm, BOD 126.2 ppm, COD 123.7 ppm, turbidity 22.3 ppm, $NH_4^+-N 9.30 ppm$, alkalinity 121 ppm, hardness 121 ppm, Cl 44.3 ppm, $SO_4--$ 88.9 ppm, Pb 0.0052 ppm, Zn 0.0079 ppm, Cu 0.0124 ppm, Mn 0.0050 ppm, respectively. 2) Discharged amount of sewage in Jinju City was $38,720 m^3/day$. BOD loading of the Nam River discharged from the sewage ditches was 4.93 ton/day, and her BOD loading discharged from the Jinyang Lake was 6.94 ton/day. 3) Heavy metals content of the sewage were comparatively low, and then it would not influence the water quality of the Nam River. But $NH_4+$ contents were very high at all sewage ditches. Therefore, the sewage would not suitable for the agricultural irrigation water.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.34 no.1
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• pp.57-62
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• 2008

No matter how small amount of heavy metals it may be cause skin allergies through percutaneous adsorption when existing in cosmetic products as impurities. In order to develop a highly sensitive method for simultaneous determination of $Pb^{2+},\;Fe^{2+},\;Cu^{2+},\;Ni^{2+},\;Zn^{2+},\;Co^{2+},\;Cd^{2+},\;and\;Mn^{2+}$ in coloring agents and cosmetic products with rapidity and accuracy, we carried out the determination on ion chromatography. All of these metals are well separated through a bifunctional ion-exchange column(IonPac CS5A) and detected by post-column reaction and spectrophotometric detection. The calibration graphs are linear($r^2>0.999$) in the range $0.1{\sim}1000{\mu}g/mL$. Detection limits for 200 ${\mu}L$ of sample solution are at the level of ${\mu}g/L$, which is sufficient for judging whether the product is safe or not. The relative standard deviations(RSDs) of the retention time and the peak area are less than 0.21 and 1.24%, respectively. The recovery rates are $97{\sim}104%$. The new method was applied to analyze the amount of heavy metals which were contained in 22 cosmetic products and 11 coloring agents.

• Korean Journal of Heritage: History & Science
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• v.37
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• pp.267-284
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• 2004

As an initial step to understand the transitions in Korean bronze technology the present study has examined metallurgical microstructures of 8 artifacts excavated from the Silla Wang-Gyong site in Kyongju. Important trends have been found in alloy compositions and also in manufacturing processes. In the design of alloys, the Sn content was apparently changing toward the peritectic point, 22 mass %, of the Cu-Sn phase diagram while the Pb addition was intentionally avoided. This trend in composition was found accompanied by the introduction, subsequent to casting, of such special thermo-mechanical treatments as quenching and forging in artifact manufacture. In addition, the Sn content in alloys containing a significant amount of As was relatively low and no evidence of forging was observed in them. The use of quenching and forging and the rejection of Pb and As from alloys are all necessary requirements if the brittle nature of high Sn alloys is to be overcome in bronze working. This paper will show that the Wang-Gyong era corresponds to that of innovations leading to the technical climax in Korean bronze tradition, which has been maintained up to the present.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.5
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• pp.118-127
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• 2021

Recently, the public's interest in the air environment has increased, and public health is threatened by fine particulate matter. Furthermore, the government continues efforts to improve air quality by expanding the monitoring of air pollutants and reinforcing environmental standards. Since air quality differs depending on the region in the Korean Peninsula, it is currently necessary to identify the cause and search for influencing factors. In this study, the atmospheric environment and regional differences in cities located in the Chungnam Province were observed. As a research method, regression analysis was performed for weather conditions, such as temperature, wind speed, precipitation, and season and targeted at air pollutants, such as SO₂, NO₂, CO, O₃, PM₁₀, and PM_2.5, as well as heavy metals contained in particulate matter, such as Pb, Cd, Cr, Cu, Ni, As, Mn, Fe, Al, Ca, and Mg. In the case of PM₁₀, the concentrations of Mn(0.4884) in Cheonan, CO(0.3329) in Dangjin, and Mg(0.5691) in Seosan were highest. In the case of PM_2.5, Cheonan NO₂(0.4759), Dangjin CO(0.4128), and Seosan NO₂(0.3715) were significantly affected. In summary, the influencing factors vary according to the region in Chungnam province in terms of air quality, and there is a difference in the degree of contribution. Therefore, it is considered that the Korean government's management of air quality is required for each region.

• Journal of Mushroom
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• v.20 no.1
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• pp.22-28
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• 2022

In order to provide basic data for preparing management standards and to verify the safety of the Chinese oak mushroom-derived moisturizing medium-which is synthesized and imported in large quantities-the presence of 321 residual pesticides, 7 heavy metals, and 3 radioactive materials was analyzed in the moisturizer samples. Examination of residual pesticides in seven moisturizing medium samples prepared using the Chinese oak mushroom and three domestic sawdust samples used for mushroom culture revealed the presence of cypermethrin and iprodione in three moisturizer samples, but the contents of these pesticides were below the standard limits. Zn was detected in ten samples, Cu was detected in nine samples, and Ni was detected in four samples, but their contents were below the standard limits. Pb, Cd, Cr, and Hg were not detected in any sample. No radioactive materials were detected in the samples. In addition, fruiting bodies of the oak mushroom were observed in each medium. Examination did not reveal the presence of any residual pesticides or harmful compounds. In this study, the use of the moisturizing medium prepared using the Chinese oak mushroom was found to be safe. As residual pesticides, heavy metals, and radioactivity-even in trace amounts-remain concentrated in the human body, continuous verification of the safety of hazardous substances and pollutants during the systematic cultivation and management of these mushrooms is required.

• Analytical Science and Technology
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• v.22 no.3
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• pp.235-246
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• 2009

The analyses of minor and trace elements in glass debris were performed using LA-ICP-MS in order to identify manufacturers using real commercial samples. At first, a calibration curve was made using standard glass samples of NIST 610, 612, 614 and 616. $^{29}Si$ was used as an internal standard, and the ratios of metal/Si for each metal were compared with their concentrations. Based on elements in each sample and standard materials, 24 metals were quantified and the LOD in analysis, according to the blank sample, was in the range of 0.11 mg/kg (Ti)-4.91 mg/kg (Ca). Eleven samples from two manufacturers were collected and five sub-samples were taken from each sample for analysis. 15 elements (Co, Ce, Ca, Mn, Sr, Ba, Li, Rb, U, La, Th, Na, Al, Zr and Hf) were selected to identify manufacturers because some elements (Cu, Cr, Cd and Ni) were below the detection limit and some elements (Ti, Pr, Mg, Nb, Nd) were absent in the analysis of standards and others (Pb and Sn) had a problem of homogeneity. The attempts to identify manufacturers and the manufacturing period were performed through a triangular diagram. In the manufacturer discrimination by discriminant analysis, a canonical discriminant function was made based on Mn, Ce and Rb, and each sample could be identified.