• 한국수산과학회지
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• 제49권1호
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• pp.7-12
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• 2016

Total mercury (TM) is a hazardous element that is of particular concern to human health. Due to the diversity of dietary habits among fishes, tissue-specific analysis of hazardous elements is necessary. In this study, the tissue-specific TM in cultured fish was analyzed to conduct risk assessment. The highest concentrations of TM were found in the farmed marine fish Pagrus major (0.111 mg/kg) and in the farmed freshwater fish Channa argus (0.162 mg/kg). TM concentration was significantly correlated with total fish length (P<0.01). Significant differences in TM were found between three types of fish tissue, with the concentration in fish muscle being significantly higher than those of gill or liver (P<0.01). Moreover, the tissue-specific TM concentrations of farmed freshwater fish were significantly higher than those of farmed marine fish (P<0.01). According to the risk assessment, the TM body exposure rate of muscle and liver in cultured fishes ranged from 0.001 to 0.389% of the Provisional Tolerable Weekly Intake. Therefore, these results showing the tissue-specific TM contents of cultured fish could be useful to assess the health risks of Korean dietary habits.

• 한국환경과학회지
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• 제27권12호
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• pp.1279-1290
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• 2018

Sea gulls are high trophic level consumers in the coastal environment, and thus, which have been widely used to monitor contamination biomagnified through a food web. However, such monitoring studies using sea gulls have been rare in the Korean literature. The National Environmental Specimen Bank chose eggs of a black-tailed gulls (Larus crassirostris) to serve as an environmental specimen for the long-term monitoring of the coastal ecosystem affected by terrestrial pollutants. Black-tailed gull eggs were collected from Baengnyeongdo, Hongdo and Uleungdo, and their DDTs and total mercury content were determined. The highest concentration of ${\Sigma}DDTs$ was $231.6{\pm}106.1{\mu}g/kg$ wet in Baengnyeongdo, followed by $230.0{\pm}123.8{\mu}g/kg$ wet in Ulleungdo, and $117.7{\pm}18.3{\mu}g/kg$ wet in Hongdo. In addition, total mercury was detected at $414.5{\pm}97.6{\mu}g/kg$ wet in Ulleungdo, $363.9{\pm}123.6{\mu}g/kg$ wet in Hongdo, and $237.5{\pm}42.3{\mu}g/kg$ wet in Baengnyeongdo. Relatively high concentrations of the target pollutants were recorded in specimens from Ulleungdo. Additional comprehensive and prolonged studies are required to elucidate spatial and temporal patterns of contamination in black-tailed gull eggs with regard to monitoring contaminant trends in eggs and prey.

• 한국지구과학회지
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• 제42권1호
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• pp.118-131
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• 2021

본 연구의 목적은 중학교 영재 학생들이 수행한 증거 기반 추론의 특징을 조사하는 것이었다. 연구를 위한 자료는 수도권에 위치한 한 대학교의 영재 교육원에서 중학교 영재 학생들이 비대면 방식으로 진행한 탐구 과제를 통해 수집되었다. 학생들에게 수성의 최대 이각을 관측한 자료를 제공하고 이 자료를 이용하여 수성의 공전 궤도를 작도하게 하였다. 또, 작도 전에 수성의 궤도에 대한 자신의 가설을 진술하게 하였으며 작도 결과를 증거로 삼아 수성 궤도의 모양을 추론하게 하였다. 학생들이 제출한 보고서의 내용을 분석하여 수성의 공전 궤도 모양에 관한 판단 유형을 5가지로 분류하고 가설 및 증거에 관한 추론 유형을 4가지로 분류한 후, 판단 유형에 따른 증거 기반 추론의 특징을 정리하였다. 분석 결과를 토대로, 증거 기반 추론에서는 증거에 대한 적절한 해석이 중요하고, 이론과 증거의 조화가 핵심적인 역할을 하며, 복수의 가설을 상정하는 것이 유리할 수 있음을 논의하였고, 지구과학 교육을 위한 시사점을 제안하였다.

• Geomechanics and Engineering
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• 제24권5호
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• pp.419-430
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• 2021

Investigation on the compressibility and shear strength of compacted loess is of great importance for the design and operation of engineering infrastructures in filling area. In this study, the mechanical behaviors of Yan'an compacted loess are investigated at various dry densities and water contents by conducting one dimensional compression and direct shear tests. And the elastic compressibility, plastic compressibility, yield stress and strength are obtained from the experiments. Results show that when water content increases, plastic compressibility parameter increases, but yield stress decreases. However, the increase of dry density leads to a decrease in plastic compressibility parameter but an increase in yield stress. In addition, elastic compressibility parameter is found to be a constant which is irrelevant to water content and dry density. As for strength, cohesion and internal friction angle is directly proportional to dry density, but inversely proportional to water content. Moreover, the mercury intrusion porosimetry (MIP) and scanning electron microscope (SEM) tests were also performed to observe the pore size distribution and microstructure of the specimens. Finally, by using results of MIP and SEM tests, the compressibility and strength behaviours of Yan'an compacted loess are explained from the perspective of pore-size distribution and microstructure.

• 한국식품영양학회지
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• 제13권6호
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• pp.595-601
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• 2000

광주광역시에서 생산·유통되고 있는 농산물 총 80개 품목(양파, 파, 마늘, 상치, 배추, 고추, 시금치. 무, 배, 복숭아)을 구입하여 중금속 및 미량금속 함유량을 조사한 결과 다음과 같은 결과를 얻었다. 수은은 모든 검체에서 검출되지 않았으며, 비소는 0.001 ppm이하의 결과를 보였다. 카드뮴과 납의 경우 각각 N.D.∼0.088 ppm과 N.D.∼0.096 ppm으로 검출되어 자연 함유량 수준으로 판단된다. 또한 농산물의 생육에 필수 원소로 작용하는 구리, 망간과 아연의 함유량은 0.109∼1.072 ppm, 0.829∼6.195 ppm, 0.731 ∼6.176 ppm으로 검출되었다.

• 환경생물
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• 제22권3호
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• pp.369-375
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• 2004

참게(E. sinensis)의 유생 생장에 미치는 기초적인 환경 및 생물학적 정보를 얻기 위해 본 실험을 실시하였다. 참게 유생을 카드뮴과 수은의 0.1, 0.2, 0.3 ppm농도에 처리하였다. 참게의 생존율과 카드뮴과 수은의 중금속 농도와 양의 상관을 나타내었다. 그런데 96시간 사육시 카드뮴과 수은의 반수치사농도는 유생 단계간 유의한 차이를 나타내었다. 반수치사농도는 카드뮴이 수은보다 높았으므로 수은이 더 치명적이였다. 중금속의 축적은 카드뮴과 수은 모두 메가로파 시기부터 급격히 증가하였다. 따라서 참게의 유생의 생육에서 카드뮴과 수은은 참게 유생의 생존에 치명적이며 생물농축이 일어났다.

• Nano
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• 제13권10호
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• pp.1850116.1-1850116.14
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• 2018

In this study, we report the mercury ions ($Hg^{2+}$) mediated phosphorus-containing carbon dots (PCDs) as a selective "off-on" fluorescence probe for glutathione (GSH), cysteine (Cys) and homocysteine (Hcys). PCDs obtained by hydrothermal reaction are sensitive to $Hg^{2+}$ ions and its fluorescence can be significantly quenched owing to the electron transfer from the lowest unoccupied molecular orbital (LUMO) of PCDs to $Hg^{2+}$. Interestingly, the weak fluorescence of $Hg^{2+}$-mediated PCDs could be gradually recovered with the addition of GSH, Cys and Hcys. This can be attributed to the formation of $Hg^{2+}-S$ complex due to the super affinity of $Hg^{2+}$-sulfydryl bond. The formation of $Hg^{2+}-S$ complex extremely reduces the oxidation ability of $Hg^{2+}$ that inhibits the electron transfer from LUMO of PCDs to $Hg^{2+}$ and re-opens the native electron transition from LUMO to the highest occupied molecular orbital (HOMO) of PCDs. Thus, the green fluorescence of PCDs is switched on. Furthermore, the present $Hg^{2+}$-mediated PCDs assay exhibits a high selectivity for GSH, Cys and Hcy and has been successfully used to detect the total biothiols content in human urine samples.

• Journal of Plant Biology
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• 제17권4호
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• pp.158-162
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• 1974

Some ecological attributes of perennial plants and Pb contamination were analyzed for study plots near an entrance of Nevade Test Site at Mercury Valley, Nye County, Nevada. The surface of the desert pavement soil was composed of stones (1 to 4cm diameter). The underside of each stone was coated with coarse and fine sand (about 90%). The profiles of soil were constituted with the A-horizon and C-horizon only. The soil pH at the plots ranges from 7.6 to 8.5, C/N was 13 and cation exchange capacity showed 15me/100g. Nine species and 42 number of individuals were found in all plots. Franseria dumosa and Larrea divaricata were dominant species. The discrete clumps of vegetation were consisted of 9 species of common perennials and these were covered about 25% on desert pavement, on the other words, bare area without vegetation was about 75%. The size and spacing of the plants was irregular. Community coefficient as comparison between shrub species in these study area and those in near the low elevation desert indicated a low degree of similarity. Density, cover and productivity in the study plots as compared with those in the nearest study areas in Mercury Valley showed a higher value. The soils in the studied area involved high heavy metal contents in the plant tissue was higher than those of its soil. The leavds of Lycium andersonii tended to accumulate more Zn and Mo than those of the other species. Larrea divaricata leaves accumulated very high leaves of Fe and Ephedra nevadensis were generally high in Mn. Lead contamination was apparent in foliage of desert vegetation collected alongside the roadway, reflecting the variation in traffic volume. Lead contents greater than fifteen-fold of normal (low traffic) were found in plant foliage alongside the heavily traveled roadway. Lead content of old foliage by the heavily traveled roadway was as much as 129 ppm but that of new foliage 17 ppm only.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1368-1370
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• 2003

Conventional methods investigating soil Hg contamination are time-consuming and expensive. A quicker method is developed to predict soil Hg content with convolved HyMap, ASTER, and TM spectra. The prediction accuracy for each sensor is satisfactory and similar. It suggests that low spectral resolution is not a limitation for predicting soil Hg content. Correlation analysis reveals that Hg -sorption by iron oxides is the mechanism by which to predict spectrally featureless Hg with reflectance spectra. Future study with field measurements and remote sensing data is recommended.

• 한국환경보건학회지
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• 제43권2호
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• pp.103-110
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• 2017

Objectives: This study was performed to provide basic data for the re-establishment of standards (criteria) and analytical methods for hazardous metals in nail enamel. Methods: Ten metals (lead; Pb, arsenic; As, cadminum; Cd, antimony: Sb, cobalt; Co, nikel; Ni, copper; Cu, chromium; Cr, aluminum; Al, and mercury; Hg) were measured in 67 commercial nail enamels containing glitter and/or pearls. The content of hazardous metals (excepting Hg) was determined by using an inductively coupled plasma-optical emission spectrophotometer (ICP-OES) after microwave digestion. Mercury content was measured by a mercury analyzer without any preparation. Results: The detected ranges of the intact samples were as follows: $ND-1.756{\mu}g/g$ for Pb, $ND-1.24{\mu}g/g$ for As, ND for Cd, $ND-20.41{\mu}g/g$ for Sb, $ND-12.36{\mu}g/g$ for Co, $ND-7.908{\mu}g/g$ for Ni, $0.088-79.27{\mu}g/g$ for Cu, $0.281-18.54{\mu}g/g$ for Cr, $13.78-3563{\mu}g/g$ for Al, and $ND-0.044{\mu}g/g$ for Hg. After centrifugation, the detected ranges of supernatant were as follows: $ND-0.435{\mu}g/g$ for Pb, $ND-0.504{\mu}g/g$ for As, ND for Cd, $ND-0.035{\mu}g/g$ for Sb, $ND-13.17{\mu}g/g$ for Co, $ND-0.232{\mu}g/g$ for Ni, $0.117-90.07{\mu}g/g$ for Cu, $0.174-2.787{\mu}g/g$ for Cr, and $9.459-1565{\mu}g/g$ for Al. The results of this analysis showed that the levels of heavy metals such as Pb, As, and Sb were much higher in the intact samples than those of supernatant. Conclusion: In the present study, we found that the levels of hazardous metals were significantly different depending on the status of the presence of glitter. Based on the results, we recommend that the product consumer refrain from prolonged application of nail enamel, avoid biting or chewing the nails, and wear gloves during cooking and washing dishes.