• Title/Summary/Keyword: environmental science

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Effect of the Chemical Reduction by Ferrous ions on Chromate Toxicity to Daphnia magna

  • Park, Kyeong S.;Man B. Gu;Kim, Sang D.
    • Proceedings of the Korea Society of Environmental Toocicology Conference
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    • 2001.05a
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    • pp.122-122
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    • 2001

  • The reaction kinetics of hexavalent chromium with ferrous ions were studied to determine the influence of reduction on the toxicity of chromium to aquatic organisms. The changes in chemical forms of the chromate in the presence of ferrous ions were examined in a bioassay system using Dphnia magna as a test organism. (omitted)

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Evaluation of Methods for Cyanobacterial Cell Lysis and Toxin (Microcystin-LR) Extraction Using Chromatographic and Mass Spectrometric Analyses

  • Kim, In S.;Nguyen, Giang-Huong;Kim, Sung-Youn;Lee, Jin-Wook;Yu, Hye-Weon
    • Environmental Engineering Research
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    • v.14 no.4
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    • pp.250-254
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    • 2009

  • Contamination of microcystins, a family of heptapeptide hepatotoxins, in eutrophic water bodies is a worldwide problem. Due to their poisoning effects on animals and humans, there is a requirement to characterize and quantify all microcystins present in a sample. As microcystins are, for most part, intracellular toxins produced by some genera of cyanobacteria, lysing cyanobacterial cells to release all microcystins is considered an important step. To date, although many cell lysis methods have been used, little work has been conducted comparing the results of those different methods. In this study, various methods for cell lysis and toxin extraction from the cell lysates were investigated, including sonication, bead beating, freeze/thaw, lyophilization and lysing with TritonX-100 surfactant. It was found that lyophilization, followed by extraction with 75% methanol, was the most effective for extracting toxins from Microcystis aeruginosa cells. Another important step prior to the analysis is removing impurities and concentrating the target analyte. For these purposes, a C18 Sep-Pak solid phase extraction cartridge was used, with the percentage of the eluent methanol also evaluated. As a result, methanol percentages higher than 75% appeared to be the best eluting solvent in terms of microcystin-leucine-arginine (MC-LR) recovery efficiency for the further chromatographic and mass spectrometric analyses.

  • https://doi.org/10.4491/eer.2009.14.4.250 인용 PDF KSCI KPUBS

An Investigation on High School Students' Chemistry-Related Environmental Conceptions and Environmental Attitudes (고등학생들의 화학 관련 환경 개념 및 환경에 대한 태도 조사)

  • Han, Jae-Young;Kang, Suk-Jin;Noh, Tae-Hee
    • Journal of The Korean Association For Science Education
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    • v.20 no.2
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    • pp.344-352
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    • 2000

  • In this study, high school students' environmental conceptions and attitudes, and their relationships with affective variables (self-esteem, enjoyment of science lesson, and leisure interest in science) were investigated. Students' environmental conceptions were found to be low, and male students' environmental conceptions were higher than female students. However, the environmental attitudes of female students were more positive than those of male students. There were no differences between male and female students in the ecocentric attitudes, but male students had more egocentric attitudes than female students. Students of higher prior science achievement level possessed higher level of environmental conceptions than their counterparts. Among the affective variables studied, leisure interest in science was significantly correlated with environmental attitudes.

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