• Economic and Environmental Geology
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• v.52 no.6
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• pp.509-517
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• 2019

The birnessite (7Å manganate, δ-MnO₂) which is a manganese oxide and comprises manganese nodules, is a major manganese mineral on the earth surface and a precursor in the synthesis of todorokite. In this study birnessite was synthesized by three different methods: Feng et al. (2004) and Luo et al. (1998) based on redox reaction and Ma et al. (1999) based on reduction reaction. 12 birnessite samples were synthesized by different combinations of Na⁺ and K⁺ cations based on the base (OH^-) and permanganate (MnO₄^-) reagents in the synthesis. The mineral compositions of synthesized birnessite were identified by XRD, and the two cation ratio in the mineral was measured by ICP. The products obtained after hydrothermal treatment of Mg-buserite, by the precursor of birnessite, was examined by XRD, and then phase transition to todorokite and their characteristics were compared. Our results show that the byproducts and the characteristics of phase transition by each synthetic method have different trends. Hausmannite (γ-Mn₃O₄) and feitknechtite (β-MnOOH) were formed by both methods in the redox reaction mechanism. By Feng et al. (2004)'s method, manganite (γ-MnOOH) phase only appeared when cation was predominantly Na⁺. Two birnessite samples synthesized by redox reaction mechanism showed phase transition to todorokite (10Å manganate, OMS-1) when both NaOH and KMnO₄ were used together. However, single-phase birnessite was formed by Ma et al. (1999)'s method, and phase transition was confirmed only for the sample when the cation was only composed of Na⁺.

• Journal of Korea Soil Environment Society
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• v.5 no.2
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• pp.23-31
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• 2000

The objective of this study was to develop an effective separation and quantification method for kerosene and diesel in a mixed petroleum fuel (gasoline, kerosene, and diesel) contaminated environmental samples. This investigation was directed to prove the hypothesis that if the source of petroleum fuels were identical, the peak-area ratios of a reference n-alkane to other n-alkane peaks should be a constant even at the different concentrations. In addition, experimental recovery rates were determined to select the reference peaks of kerosene and diesel for peak area ratio measurements. The experimental results showed that the peak area ratios were constant among the samples having different concentrations when the ratios were calculated from areas of $C_{l3}$, $C_{l4}$, and $C_{15}$ peaks for kerosene and $C_{l6}$ and $C_{l7}$ peak for diesel as reference n-alkane peaks. The recovery rates were evaluated by comparing the relative peak area ratios of each reference peaks after making pairs of the kerosene and diesel reference peaks in the samples contained a known amount of gasoline, kerosene, and diesel. The recovery rates(%) Were 107.0$_{{\pm}20.6}$/86.6/ sub $\pm$15.9/ for kerosene- $C_{13}$/diesel- $C_{16}$, 99.6$\pm$$_{17.2}$/86.6$_{{\pm}15.9}$ for kerosene- $C_{14}$/diesel- $C_{16}$, 73.9/$\pm$14.4//86.6$_{{\pm}sub 15.9}$ for kerosene- $C_{15}$ /diesel- $C_{16}$, 109.4$_{{pm}0.8}$/75.9$_{{pm}4.7}$ for kerosene- $C_{13}$/diesel- $C_{17}$, 107.4$_{{pm}7.9}$/75.9$_{{pm}4.7}$ for kerosene- $C_{14}$/diesel- $C_{17}$, and 95.7$_{{pm}4.6}$ /75.9/$\pm$14.6//75.9$_{{pm$}4.7}$ for kerosene- $C_{15}$ /diesel- $C_{17.}$ The above experimental results confirm that all of the reference peak pairs of kerosene and diesel are applicable to the quantitative analysis for the mixed fuel contaminated samples, but the kerosene- $C_{15}$ /diesel- $C_{l7}$ peaks are recommended since the pair has a lower standard deviation than the other pairs.s..s.s.s..s..s.s.s.s.s.

• Journal of the Korean Association of Geographic Information Studies
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• v.14 no.3
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• pp.236-256
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• 2011

Forest carbon stocks change due to land use change is an important data required by UNFCCC(United Nations framework convention on climate change). Spatially explicit estimation of forest carbon stocks based on IPCC GPG(intergovernmental panel on climate change good practice guidance) tier 3 gives high reliability. But a current estimation which was aggregated from NFI data doesn't have detail forest carbon stocks by polygon or cell. In order to improve an estimation remote sensing and GIS have been used especially in Europe and North America. We divided research trends in main countries into 4 categories such as remote sensing, GIS, geostatistics and environmental modeling considering spatial heterogeneity. The easiest way to apply is combination NFI data with forest type map based on GIS. Considering especially complicated forest structure of Korea, geostatistics is useful to estimate local variation of forest carbon. In addition, fine scale image is good for verification of forest carbon stocks and determination of CDM site. Related domestic researches are still on initial status and forest carbon stocks are mainly estimated using k-nearest neighbor(k-NN). In order to select suitable method for forest in Korea, an applicability of diverse spatial data and algorithm must be considered. Also the comparison between methods is required.

• Korean Journal of Environmental Agriculture
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• v.32 no.1
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• pp.70-77
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• 2013

BACKGROUND: Nitroxoline is an antibiotic agent. It is used for the treatment of the second bacterial infection by the colibacillosis, salmonellosis and viral disease of the poultry. When the nitroxoline is indiscreetly used, the problem about the abuse of the antibiotics can occur. Therefore, this study presented the residue analytical method of nitroxoline in food for the safety management of animal farming products. METHODS AND RESULTS: A simple, sensitive and specific method for nitroxoline in chicken muscle by high performance liquid chromatograph with PDA was developed. Sample extraction with acetonitrile, purification with SPE cartridge (MCX) were applied, then quantitation by HPLC with C18 column under the gradient condition with 0.1 % tetrabutylammonium hydroxide-phosphoric acid and methanol was performed. Standard calibration curve presented linearity with the correlation coefficient ($r^2$) > 0.999, analysed from 0.02 to 0.5 mg/L concentration. Limit of quantitation in chicken muscle showed 0.02 mg/kg, and average recoveries ranged from 72.9 to 88.1 % in chicken muscle. The repeatability of measurements expressed as coefficient of variation (CV %) was less than 12 % in 0.02 and 0.04 mg/kg. CONCLUSION(S): Newly developed method for nitroxoline in chicken muscle was applicable to food inspection with the acceptable level of sensitivity, repeatability and reproducibility.

• Korean Journal of Environmental Biology
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• v.23 no.2 s.58
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• pp.191-199
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• 2005

The community structure, vertical distribution and harpacticoids composition of the meiofauna community were observed from five stations in Marian Cove, King George Island and one station on the northeastern side of Nelson Island. Sample was taken by a free-fall corer in December 2002. Generally, 11 taxa of meiofauna were found, and meiofauna abundance ranged from 322 to 1575 indiv. $10cm^{-2}$ (mean 781 indiv. $10cm^{-2}$). Nematodes were the most dominant group, making up $89\%$ of total meiofauna, followed by harpacticoids $(6.8\%)$. Benthic harpacticoids appeared 19 species of nine families at all the stations, and most various taxa appeared at station B (13 species of seven families). For vertical distribution, more than $70\%$ of meiofauna was concentrated in the upper $0\~2cm$ sediment layers, and the density abruptly decreased with depth in all the stations. Total biomass of meiofauna varied between 41 and $360{\mu}gC\;10cm^{-2}$, and overall mean biomass was $205{\mu}gC\;10cm^{-2}$. Also nematodes had the highest percentage of total maiofauna biomass $(62.4\%)$. The analysis results of Canonical Correspondence Analysis between meiofauna community and sediment grain size showed that polychaets, oligochaets and cumaceans were influenced by silt&cray, and sand, granule and pebble had a influence on harpacticoids, kinorhynchs and ostracods respectively. But nematodes were not affected by sediment grain size.

• Economic and Environmental Geology
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• v.35 no.6
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• pp.523-532
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• 2002

The rare earth elements (REE) and Nd, Sr and noble gas isotopic compositions eHer'He, 4$^{\circ}$Arp6Ar) for the Quaternary alkali basaltic rocks and mantle xenoliths in the basaltic rocks from the Baegryongdo were investigated to decipher the origin of alkali basaltic magma and xenolith beneath the Sino-Korean craton. Analytical results are summarized as follows; (1) The alkali volcanic rocks with voluminous xenoliths which are represented by the Mg-olivine and clinopyroxene dominant spinel-lherzolite in the Baegryongdo consist mainly of the basalt-mugearite and basaltic andesite. (2) The REE pattern of alkali basaltic rocks characterized by high HREE is similar to that of oceanic island basalt (OlB). Relatively concordant REE patterns of the basaltic rocks suggest that the alkali basaltic magma be formed by the identical source materials. (3) The Nd-Sr isotopic data of the alkali basaltic rocks suggest that the alkali basaltic magma be originated from the depleted mantle source with a little contamination of the continental crustal materials. (4) The $^3$He/ $^4$He ratios in olivines of xenoliths ranging from 5.0${\pm}$1.lRa to 6.7${\pm}$1.3Ra are lower than that of MORB (ca. 8.0Ra). It suggest that the xenolith be derived from the subcontinental lithospheric mantle. However, the high $^3$Her'He value of 16.8${\pm}$3.IRa at 1800$^{\circ}$C fraction (sample no OL-7) might be resulted from the post-eruptive cosmogenic $^3$He. The 4OAr/ 36 Ar ratios in olivines of mantle xenoliths are comparable to that of atmospheric argon, and are much lower than that of the MORB type mantle. These facts can lead to conclusion that the olivine of the xenolith in the Baegryongdo is affected by the post-eruptive atmospheric contamination during the slow degassing process.

• Economic and Environmental Geology
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• v.45 no.5
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• pp.487-502
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• 2012

This paper is focused on mineral compositions, microstructures and distributional characters of remained grains in the fault rocks collected from a fault developed in Yongdang-ri, Yangbuk-myeon, Gyeongju City, Korea, using X-ray diffraction (XRD), optical microscope, laser grain size analysis and fractal dimension analysis methods. The exposed fault core zone is about 1.5 meter thick. On the average, the breccia zone is 1.2 meter and the gouge zone is 20cm thick, respectively. XRD results show that the breccia zone consists predominantly of rock-forming minerals including quartz and feldspar, but the gouge zone consists of abundant clay minerals such as chlorite, illite and kaolinite. Mineral vein, pyrite and altered minerals commonly observed in the fault rock support evidence of fault activity associated with hydrothermal alteration. Fractal dimensions based on box counting, image analysis and laser particle analysis suggest that mineral grains in the fault rock underwent fracturing process as well as abrasion that gave rise to diminution of grains during the fault activity. Fractal dimensions(D-values) calculated by three methods gradually increase from the breccia zone to the gouge zone which has commonly high D-values. There are no noticeable changes in D-values in the gouge zone with trend being constant. It means that the bulk-crushing process of mineral grains in the breccia zone was predominant, whereas abrasion of mineral grains in the gouge zone took place by continuous fault activity. It means that the bulk-crushing process of mineral grains in the breccia zone was predominant, whereas abrasion of mineral grains in the gouge zone took place by continuous fault activity. Mineral compositions in the fault zone and peculiar trends in grain distribution indicate that multiple fault activity had a considerable influence on the evolution of fault zones, together with hydrothermal alteration. Meanwhile, fractal dimension values(D) in the fault rock should be used with caution because there is possibility that different values are unexpectedly obtained depending on the measurement methods available even in the same sample.

• Economic and Environmental Geology
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• v.51 no.5
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• pp.401-407
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• 2018

For the treatment of heavy metals in the mine drainage from the closed mine area, various methods such as passive, active and semi-active treatments are considered. Among contaminated elements in the mine drainage, Mn is one of the difficult elements for the treatment because it needs high pH over 9.0 for its concentration to be reduced. In this study, the efficiency of various slag complex reactors (slag (S), slag+limestone (SL) and slag+Mn coated gravel (SG)) on Mn removal in the presence of Fe, which is a competitive element with Mn, was evaluated to investigate effective methods for the treatment of Mn in mine drainage. As a result of experiments on Mn removal without Fe during 358 days, using influent with $30{\sim}50Mn{\cdot}mg/L$ and pH 6.7 on the average, S reactor showed continuously high Mn removal efficiency with the average of 99.9% with pH 8.9~11.4. Using the same reactors, Mn removal experiments with Fe during 237 days were conducted with the influent with $40{\sim}60Mn{\cdot}mg/L$. The pH range of effluent reached to 6.1~10.0, which is slightly lower than that of effluent without Fe. S reactor showed the highest range of pH with 7.1~9.9, followed by S+L and S+G reactor. However, the efficiency of Mn removal showed S+L>S>S+G with the range of 94~100%, 68~100% and 68~100%, respectively in spite of relatively low pH range. S+L reactor showed the most resistance on Fe input, which means other mechanisms such as $MnCO_3$ formation by the carbonate prouced from the limestone or autocatalysis reaction of Mn contributed to Mn removal rather than pH related mechanisms. The evidence of reactions between carbonates and Mn, rhodochrosite ($MnCO_3$), was found from the X-ray diffraction analysis of precipitates sample from S+L reactor. From this study, the most effective reactors on Mn removal in the presence of Fe was S+L reactor. The results are expected to be applied for the Mn containing mine water treatment in the presence of Fe within the relatively low range of pH.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.4
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• pp.314-323
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• 2006

This study was conducted to identify ingredients of thinners and to confirm reliability of material safety data sheets (MSDS) of thinners for public and workers' health. The 41 thinner products were collected from paint shops located in Busan and Gyeongnam province. The 12 thinner products among them were identified using product MSDS. GC-MSD was used to analyze 41 kinds of thinners qualitatively and quantitatively. The 12 products MSDS were compared with thinner's component through qualitative analysis to confirm MSDS. Chemical ingredients, such as Benzene, Toluene, and Xylene etc., of thinners were analysed in quantity. The 41 thinner products contained 17 disclosed specific, trade name, or generically described chemical solvent ingredients. These 17 ingredients came under 6 classes: alcohols, aromatic hydrocarbons, esters, glycol ethers, ketones, and mixtures. These 17 ingredients were important in the view of industrial hygiene and had occupational exposure limit in the ambient, such as toluene, xylene, acetone, nonane, EGEE, heptane, cumene, MIBK, indene, tri-methyl benzene, etc, were found in 41 kinds of thinners. Aromatic hydrocarbons were the most identified ingredient in thinners. Especially, the benzene, which induces leukemia, was found in 4 kinds of thinners. The content rates of benzene in thinners were 0.25~1.18%. The benzene in enamel thinner, which were 0.39~0.72%, was highest from chemical classification. The contents of toluene, which was found from 27 kinds of thinners, were 5.35~64.16%, which were highest in sobu thinner as 58.80%. Xylene was found from 22 kinds of thinners and contents of xylene were 4.61~72.42%. Acrylic thinner's contents of xylene were 12.06~51.05%, which was most high. It was found that contents of benzene were increased and frequency of detection was decreased through comparison with other study. The MSDS possession rate of paint shops was low as 29.27%. So it did not provide information with public or workers. Mean of agreement rate between MSDS and components of thinners through qualitative analysis was 42.01% and it has wide range from 8.3% to 75%. There are many deficiencies in MSDS about component of thinners. In some case of sample, expecially, despite containing benzene, information was not written it on MSDS.

• Korean Journal of Environmental Agriculture
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• v.30 no.1
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• pp.52-59
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• 2011

BACKGROUND: This study was performed to investigate pre-harvest residue limit (PHRL) in Chwinamul, to estimate biological half-life for residue of each pesticide. Chwinamul was sprayed with pesticides of standard and double application rate. Chlorfenapyr and fenarimol were sprayed once on Chwinamul at 10 days before harvest, and it was sampled 7 times and analysed the residual change of two pesticides. METHODS AND RESULTS: Chwinamul sample was extracted with acetonitrile and partitioned with dichloromethane, and pesticide residues were determined with GCECD. Method quantitation limit (MQL) of chlorfenapyr was 0.10 mg/kg and that of fenarimol was 0.02 mg/kg. Recoveries of chlorfenapyr at two fortification levels of 1.0 and 5.0 mg/kg were $94.2{\pm}$1.70 and $99.0{\pm}1.61%$, respectively. Recoveries of fenarimol at two fortification levels of 0.2 and 1.0 mg/kg were $92.1{\pm}2.14$ and $83.1{\pm}1.98%$, respectively. CONCLUSION(s): The biological half-lives of chlorfenapyr were about 3.5 days at standard application rate, and 3.4 days at double application rate. The biological half-lives of fenarimol were about 6.0 days at standard application rate, and 5.9 days at double application rate. The PHRLs of chlorfenapyr were recommended as 13.02 and 6.25 mg/kg for 10 and 5 days before harvest, respectively. And the PHRLs of fenarimol were recommended as 2.80 and 1.67 mg/kg for 10 and 5 days before harvest, respectively.