• Korean Chemical Engineering Research
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• 제44권2호
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• pp.114-120
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• 2006

중금속을 함유하여 환경문제를 야기하고 있는 무기안료를 대체할 환경 친화적 안료 제품을 개발할 목적으로, potassium vanadate와 bismuth nitrate의 수용액으로부터 bismuth vanadate 안료를 제조할 때 공정 변수가 생성되는 안료의 물성에 미치는 영향을 실험적으로 조사하였다. 두 수용액을 각각 일정한 유속으로 서서히 첨가한 후, 반응혼합물의 1차 pH와 2차 pH를 각각 4.5와 7.0~7.5로 하여 침전을 생성시켜 반응혼합물 속에서 3시간 이상 숙성하고, $400^{\circ}C$에서 3시간 이상 소성하면 0.90 이상의 은폐율과 ${\Delta}E^*$값 1.50 이하의 색상을 지닌 bismuth vanadate 안료를 제조할 수 있었다. 반응혼합물 중 Mo의 첨가량이 증가하면 안료의 은폐력이 증가하는 경향을 나타내었으나, 다른 미량 성분들의 영향은 그리 크지 않은 것으로 나타났다.

• 농업과학연구
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• 제21권1호
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• pp.28-36
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• 1994

식육자원으로서 야생조류인 꿩과 청둥오리고기의 식품안전성에 관하여 검토한 결과는 다음과 같다. 1. 꿩과 청둥오리의 소장, 맹장과 직장에 대한 식중독균 검사에서, Salmonella속균 등 본 실험에서 검사한 3종의 식중독균은 모두 검출되지 않았다. 2. 꿩과 청둥오리의 혈액, 분, 소화기관 및 흉강장기에 대한 기생충검사에서 기생충은 발견되지 않았다. 3. 꿩과 청둥오리의 도체 근육에 대한 디스크 간이법에 의한 항생물질의 잔류검사에서, 모든 시료는 음성반응을 보였다. 4. 꿩과 청둥오리의 근육 및 간에 대한 DDT, BHT 등 7종의 농약 잔류검사에서, 모든 시료는 음성반응을 보였다. 5. 꿩과 청둥오리의 간, 근육 및 혈액에 대한 Cd 등 4종의 독성 중금속 검사에서 그 잔류량은 허용기준 이하였다. 이상의 꿩과 청둥오리에 대한 식품 안전성 검사 결과, 이들의 고기가 인체에 미치는 직접적인 위험도는 매우 낮을 것으로 사료된다.

• 생명과학회지
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• 제21권1호
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• pp.134-140
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• 2011

대전일원의 유류오염 지역의 토양으로부터 원유를 단일 탄소원으로 이용하는 총 145균주를 순수분리 하였고, 이중 생물 계면활성제 생성능이 가장 우수한 한 균주를 최종 선별하여 형태 및 생리 생화학적 특성을 조사하고 16S rRNA 염기서열을 분석을 통하여 동정한 결과 Pseudomonas sp.로 확인되어 Pseudomonas sp. Z1이라 명명하였다. 최종 선별된 Pseudomonas sp. Z1은 클로람페니콜과 암피실린 등의 항생제와 리튬, 망간, 바륨 등의 중금속에 대해 강한 내성을 갖고 있었고, 최적 온도와 pH는 각각 $30^{\circ}C$와 pH 6.0-7.0으로 확인되었다. Pseudomonas sp. Z1이 생성하는 생물 계면활성제는 배양 10시간 이후부터 배양액의 표면장력이 급격히 감소해, 배양 21시간 후에 최대 28 dyne/cm까지 감소되었고, 2% 이상의 NaCl을 첨가한 경우 배양액의 생물계면활성제의 활성이 감소하였다.

• 한국환경과학회지
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• 제1권1호
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• pp.13-21
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• 1992

The inhibitory effects of mercury ions on the growth of barley seedlings were studied and the distribution of metal elements in the organs of treated plants was investigated by using synchrotron radiation induced X-ray emission (SRIXE). Although the treatment of mercury ions caused growth inhibition, the mercury-specific increase in variable fluorescence and the abolishment of energy-dependent quenching in broken barley chloroplasts as shown by Moon et at. (1992) were not observed in the leaves of growth-inhibited seedlings. Instead the treatment of mercury decreased Fmax and Fo values. However, Fmax/Fo ratio and photochemical and nonphotochemical quenching coefficients were not affected significantly. By SRIXE analysis of $10\mu\textrm{m}$ mercury chloride treated seedlings, accumulation of mercury in roots was observed after 1 hour of treatment and similar concentration was sustained for 48 hours. Relative contents of mercury was high in roots and underground nodes where seeds were attachedl but was very low in leaves. Iron and zinc were also distributed mainly in the lower parts of the seedlings. However after 72 hours of treatment the contents of these metals in roots decreased and their distribution became more uniform, which may lead to death of the plants. These results suggest that the observed inhibitory effects on barley seedlings upto 48 hours after the treatment is not due to direct damages in the photosynthetic apparatus, but due to its accumulation in roots and the consequent retardation of the growth of barley seedlings. The decrease in Fmax and Fo is probably due to the decrease in chlorophyll and protein contents caused by the retardation of growth. The observed slow expansion of primary leaves could be also explained by the retardation of growth, but the fluorescence induction pattern from the leaves did not show characteristic symptoms of leaves under water stress.

• 한국환경과학회지
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• 제11권3호
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• pp.215-225
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• 2002

In order to evaluate the relationship between geochemical characteristics and benthic facies of the sediments from the Oenaro Island where red tide proliferation is first observed every year including this year, surface and short multiple core sediment samples were analyzed in terms of geochemical and benthic facies variation. The contents of organic carbon, carbonate, and sulfide gas were relatively low. The variation in C/N ratios, which indicate nature of organic carbon, suggested that the organic carbon recorded in the study area is composed of mixtures of marine and terrigenous organic matters. The concentration of minor elements found at the surface and multiple core sediment samples were also low as well as the enrichment factors(Ef) for the seven heavy metals indicated that the sediment of this area is not polluted significantly. The macrobenthic faunal community comprised 61 species, and their mean density was 708 ind./m2. Polychaete worms were major taxa of this benthic community. A crustacean amphipod, Melita sp. was the most abundant species accounted for 20.7% of total abundance, and the small polychaetes such as Heteromastus filiformis, Paralacydonia poradoxa, Magelona japonica and Sigambra tentaculata were the next dominant species. The macrobenthos around the Oenaro Island were more diverse and abundant than that in Gamak Bay. The benthic communities in the study area sustained somewhat different species composition based on the cluster analysis and the MDS ordination. The benthic community health condition at three stations seemed to be unbalanced, and slightly polluted based on the biological index such as BPI and BC. There was no clear relationship between the geochemistry characteristic and the benthic faunal facies attributed by the micro-algal blooms in this coastal area.

• 상하수도학회지
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• 제25권1호
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• pp.15-21
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• 2011

Arsenic is one of the most abundant contaminant found in waste mine tailings, because of it's carcinogenic property, the countries like United states of America and Europe have made stringent regulations which govern the concentration of arsenic in drinking water. The current study focuses on different treatment methods for removal of arsenic from waste water. Treatment method the high strength arsenic waste water is treated with Fe(III)-ettringite by co-precipitation method. Number of experiments were carried out to decide the optimal dosage of Fe(III)-ettringite to treat arsenic waste water. The Fe(III)-ettringite was synthesized by taking appropriate equivalent ratios of calcium oxide and ferric chloride in proportion to the arsenic. The best removal efficiencies of 94% were observed at a As/(Ca: Fe) ratio of 1:3. The maximum removal of arsenic was observed in pH range of 12. But as the pH increases the arsenic removal efficiency decreases as portlandite is formed in the pH above 12. The analysis of surface of precipitate conform the needle like structure of ettringite. This treatment technique has promising features such as, the chemicals required in the treatment as well as the sludge generated can be reduced. The operating pH range is in alkaline region which is advantageous over traditional treatment process which has lower pH. Also the co-precipitation not only helps in removal of arsenic but also heavy metals.

• 자원리싸이클링
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• 제25권6호
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• pp.65-72
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• 2016

중유 화력발전소에서 발생되는 중유회를 처리한 용출액(Fly Ash Leach Liquor; FALL)으로부터 V을 선택적으로 회수하기 위한 기초 연구를 UV 분광법을 이용해 수행하였다. Ni, Fe등이 포함된 시료를 분광법으로 V을 정량할 때, Ni, Fe등의 금속이 V 정량에 미치는 범위를 조사하였고 FALL 시료에 5.0M $NH_3$ 사용량과 pH 변화에 따른 금속의 침전율과 교반시간에 따른 금속 침전율의 최적 조건을 조사하였다. $25^{\circ}C$, pH 7.0 (5.0M $NH_3$)에서 선택적인 V의 회수 시점은 교반 시간이 1분 이내일 때로 91.5%의 회수율을 보였다.

• 한국토양비료학회지
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• 제48권6호
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• pp.666-670
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• 2015

Competition among anion species in solution for same sorption sites and soil surface can be of major significance in determining the effective mobility of any potentially adsorbing species. Major soil anion species include $OH^-$, $F^-$, $Cl^-$, $HCO_3{^-}$, $CO_3{^-}$, $NO_3{^-}$, $SO_4{^{2-}}$, and $PO_4{^{3-}}$. And some micro nutrients such as boron and molybdenum exist as $H_2BO_3{^-}$ and $MoO_4{^{2-}}$, as do some heavy metals such as chrome and arsenic as $CrO_4{^{2-}}$ and $HAsO_4{^{2-}}$. Pesticides such as 2,4,5-T and 2,4-D also exist as anions. Many anion species are retained by more complex mechanisms than the simple electrostatic attractions involved in most cation adsorption reactions. In binary system composed of two anions, the adsorption of one anion is influenced by the other anion due to the competition for the available and limited binding sites in soil constituents. The specifically adsorbed anions may compete more effectively for sorption sites than that of nonspecifically adsorbed anion. In this study, we aim to evaluate the mathematical models to determine the magnitude of concentration variations in adsorption due to competitive interactions between anions introduced to a system in binary mixtures.

• Journal of Preventive Medicine and Public Health
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• 제54권6호
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• pp.471-480
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• 2021

Objectives: Cadmium is widely used, leading to extensive environmental and occupational exposure. Unlike other organs, for which the harmful and carcinogenic effects of cadmium have been established, the hepatotoxicity of cadmium remains unclear. Some studies detected correlations between cadmium exposure and hepatotoxicity, but others concluded that they were not associated. Thus, we investigated the relationship between cadmium and liver damage in the general population. Methods: In total, 11 838 adult participants from National Health and Nutrition Examination Survey 1999-2015 were included. Urinary cadmium levels and the following liver function parameters were measured: alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma glutamyl transferase (GGT), total bilirubin (TB), and alkaline phosphatase (ALP). Linear and logistic regression analyses were performed to assess the associations between urinary cadmium concentrations and each liver function parameter after adjusting for age, sex, race/ethnicity, annual family income, smoking status, alcohol consumption status, physical activity, and body mass index. Results: The covariate-adjusted results of the linear regression analyses showed significant positive relationships between log-transformed urinary cadmium levels and each log-transformed liver function parameter, where beta±standard error of ALT, AST, GGT, TB, and ALP were 0.049±0.008 (p<0.001), 0.030±0.006 (p<0.001), 0.093±0.011 (p<0.001), 0.034±0.009 (p<0.001), and 0.040±0.005 (p<0.001), respectively. Logistic regression also revealed statistically significant results. The odds ratios (95% confidence intervals) of elevated ALT, AST, GGT, TB, and ALP per unit increase in log-transformed urinary cadmium concentration were 1.360 (1.210 to 1.528), 1.307 (1.149 to 1.486), 1.520 (1.357 to 1.704), 1.201 (1.003 to 1.438), and 1.568 (1.277 to 1.926), respectively. Conclusions: Chronic exposure to cadmium showed positive associations with liver damage.

• 한국지하수토양환경학회지:지하수토양환경
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• 제29권4호
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• pp.12-20
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• 2024

Diffusive gradients in thin films (DGT) are passive sampling devices used to determine the time-weighted average concentrations (TWAC) of contaminants. To ensure accurate performance in groundwater, it is crucial to identify environmental characteristics and maintain optimal operational conditions. This study examined the deployment time required to reach effective capacity, the thickness of the diffusive boundary layer (DBL) under stagnant water conditions, and biofilm formation on the DGT surface using groundwater samples. When using DGT with Chelex gel (A=3.14 cm²), the effective capacity was 0.7 ㎍ for Cd and 250 ㎍ for Zn, with a deployment time of 24 h. Lower Cd accumulation was due to the competition effect of coexisting ions. The DBL thickness under stagnant conditions was 0.074 cm, 93% of the diffusion gel's thickness (0.08 cm). Neglecting DBL thickness in TWAC calculations led to a 79% decrease in the determined concentration. No biofouling was observed during the 28-d DGT deployment in groundwater. In conclusion, it is essential to consider the appropriate deployment time, DBL thickness, and biofilm formation to ensure accurate DGT performance in determining contaminant levels in groundwater.