• Korean Journal of Pharmacognosy
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• v.30 no.3
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• pp.306-313
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• 1999

Polyphenol Oxidase(PPO) was purified from an extract of Ginkgo biloba leaves by ammonium sulfate fractionation followed by sephadex G-150 column chromatography, which resulted in a 18-fold increase in specific activity. The enzyme was most active at pH 8.5 and the temperature optimum for the PPO catechol oxidation reaction was $45^{\circ}C$. Heat inactivation studies showed that heating for 7, 9 and 48 min, at 80, 70 and $60^{\circ}C$ respectively caused a 50% loss in enzymatic activity and that the enzyme was completely inactivated after heat treatment at $90^{\circ}C$ for 60 min. Km values of the PPO for catechol, hydroquinone and 4-methylcatechol derived from Lineweaver-Burk plots were $6.06\;{\times}\;10^{-4}M,\;1.02\;{\times}\;10^{-3}M,\;1.41\;{\times}\;10^{-3}M$ respectively. Of the substrates tested, 4-methylcatechol was oxidized most readily and the enzyme did not oxidize monophenols. The enzyme datalyzed browning reaction was completely inhibited in the presence of reducing reagents, namely ascorbic acid, cysteine, glutathione, 2-mercaptoethanol, potassium metabisulfite at 0.5 mM level. Sodium chloride showed very little inhibition effect on Ginkgo biloba leaves PPO. Lineweaver-Burk analysis of inhibition data revealed that the inhibition by cysteine, 2-mercaptoethanol, potassium cyanide was competitive with ki values of $1.1\;{\times}\;10^{-5}M,\;2.4\;{\times}\;10^{-5}M,\;8\;{\times}\;10^{-5}M$, respectively. Among the divalent cations, $Cu^{2+}ion$ was a strong activator on PPO and $Mn^{2+}ion$ was little or no effect on PPO activity $Ni^{2+}ion$ was an inhibitor on PPO.

• Natural Product Sciences
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• v.26 no.1
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• pp.50-58
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• 2020

The study was conducted for quantitive determination of macronutrients, micronutrients and heavy metals present in Spilanthes acmella Hutch and Dalz, a traditionally used important medicinal plant. The results illustrated the presence of substantial amounts of essential nutrient elements in different parts of the plant. K and Mg were detected in the range between 36.35 ± 1.01 to 67.78 ± 1.33 g/kg and 2.17 ± 0.13 to 7.02 ± 0.84 g/kg of DWS respectively. While the essential micronutrients Fe, Na, Mn, Zn and Cu were detected in the range between 62.62 ± 12.72 to 856.95 ± 76.61 mg/kg, 365.47 ± 23.84 to 633.03 ± 38.12 mg/kg, 51.66 ± 7.77 to 186.33 ± 13.92 mg/kg, 41.87 ± 2.85 to 53.89 ± 3.79 mg/kg and 18.49 ± 2.07 to 48.71 ± 4.89 mg/kg of DWS respectively. Besides, heavy metals (Cd, Ni and Pb) detected in some of the plant samples were beyond the maximum permissible limit (MPL) of FAO/WHO for herbal medicines. The concentrations of the essential nutrient elements except zinc were significantly different in different parts of the plant (p < 0.001). Further variation in the concentrations of the elements in the plant was observed with respect to seasonal changes and geographical conditions. Nevertheless the findings corroborate ethnomedicinal significance of the plant and signify the possibilibity of utilizing its standardized products for preparation of food supplements as well as multidimensional therapeutic herbal medicines.

• Economic and Environmental Geology
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• v.33 no.3
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• pp.181-193
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• 2000

This study was undertaken to evaluate the drinking water quality based on physicochemical properties and chemical compositions of the supply water in the Daedeok Campus, and to verify the analytical reliabilities of ICP-MS and IC equipped in the Central Research Facilities at Chungnam National University , Korea. The supply water belongs to $Ca^{2+}-({HCO_3}^-+{SO_4}^{2-})$type, whereas the original water from the Daecheong lake belongs to $(Ca^{2+}-(Mg^{2+})-{HCO_3}^-$ type. Generally, temperature (14.1$^{\circ}C$), pH (6.95), Eh (0 mV), electrical conductivity (117${\mu}$S/cm) and TDS (86.975mg/l) of supply water were higher than those of original lake water . Results using WATEQ4F revealed that potentially toxic ions of the supply water might exist mainly as free metals ($M^{2+}$) and a small amount as ${CO_3}^{2-}$ and $OH^-$ complexes. Also, the water composition belongs to the kaolinite field. Calculated average enrichment indies of the supply water normalized to lake water for anions, mamor cations, toxic cations and total ions are 1.05 , 1.56, 13.05 and 1.17 , respectively. Those values of the ground water in the Daedeok Campus showed 1.71, 4.78, 5.71 and 2.49 , respectively. However , contents of all constituents of these water are within the drinking water standard. All samples were filtered before the chemical analysis. Pale yellow or yellowish brown colored materials of colloidal particles coated the filter paper to thickness of 0.02 to 0.2mm. these are mainly Fe-Cy-Zn compounds with traces of Ni and Pb, the net weights of which compounds range from 0.01to 3.20mg/l. Most elements did not show any conceivable filtering effect of Cu, Fe and Zn. Especially, mean concentration of total Fe decreased considerably from 168.52${\mu}g$/lto 42.58${\mu}g$/l by filtering .

• Economic and Environmental Geology
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• v.7 no.3
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• pp.87-100
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• 1974

This paper deals with grain size analysis, heavy mineral analysis and trace element analysis of the recent sediments of Han River basin between Cheongpyong, Gyeonggi province and Seoul. For each location the samples are taken at river shoreline, river berm and river dune. The size analysis discloses that the mean values range from $-1.37{\phi}$ to $-1.60{\phi}$, sorting values range from 0.25 to 1.84, skewness values range from -0.44 to 0.51 and kurtosis values range from -0.1 to 1.75. Based on the textural parameters, the dune sand can be distinguished from the shoreline-berm sand. The content of heavy minerals of each sample ranges from 0.04 to 4.7%. The principal heavy minerals are ilmenite, magnetite, leucoxene, garnet, amphibole, pyroxene, kyanite, zircon, monazite, tourmaline, epidote, limonite, and minor minerals are apatite, sillimanite, andalusite and olivine. In general, dune sand samples contain more heavy minerals than the samples of shoreline or berm sand. This suggests that the heavy mineral concentration is affected by wind action more than by any other causes. The content of ilmenite and leucoxene decreases, whereas the content of zircon and epidote increases as it approaches the downstream region. The differences result from the variance of geological occurrences. The emission spectrochemical analysis and colorimetry analysis revealed that the content of Ni and V in the heavy minerals of the study area are higher than those of other stream sediments in Korea. On the other hand the content of Cu, Ph, Zn, Mo, W, P, Mn, Cr, Ag and Sn are lower in the study area. It has been observed also that the contents of all the elements except for Bi are higher in this area than the samples of marine sediments of Yellow Sea.

• Ocean and Polar Research
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• v.42 no.1
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• pp.33-47
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• 2020

The bulk and partition geochemistry was studied in two sediment cores collected from the axial valley of the north-central Fonualei Rift and Spreading Center (FRSC), Lau back-arc Basin, southwest Pacific. The sediments consist of mostly volcanic ash, although minor amounts of biogenic and other components were present in some intervals. The major element composition of bulk sediments recalculated to a carbonate-free basis was in good agreement with the magma compositions of the adjacent Tofua Arc and the FRSC, with only significant difference in Mn content. The enrichment of Mn and other associated elements (e.g. Cu, Co, Ni, and P) is attributed to hydrothermal input to the sediments, as evidenced by their significant partitioning in the non-detrital phases according to the partition geochemistry. Hydrogenetic and diagenetic inputs were assessed to be relatively insignificant. Estimated hydrothermal Mn fluxes during the Holocene ranged between 5.0 and 37.1 mg cm^-2 kyr^-1, with the higher values in younger sediments, suggesting enhanced hydrothermal activity. The hydrothermal Mn fluxes comparable to or higher than those reported from other spreading centers with strong hydrothermal activities may indicate the presence of unknown hydrothermal vent sites and/or topographic restriction on the dispersal of hydrothermal plumes in the northern part of the FRSC.

• Bulletin of the Korean Chemical Society
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• v.24 no.12
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• pp.1775-1780
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• 2003

A continuous flow system has been developed to determine trace Cu(II), Mn(II), Ni(II) and Zn(II) in a large volume of water samples by a solvent sublation technique. The mixed solution of 1,10-phenanthroline(phen) and thiocyanate ion was used as ligands for the formation of their ternary complexes. The continuous system was constructed in this laboratory with a peristaltic pump, a mini shaker, three mixing bottles and a flotation cell by connecting each part with a polyethylene tube. The flotation conditions such as the flow rate of sample solution and the injection rates of ligand, buffer and surfactant solutions have been investigated to obtain the best sublation efficiencies. Each solution flowed into the flotation cell through each polyethylene tube by the peristaltic pumps. The ternary complexes were floated and extracted into MIBK in a flotation cell of 2 L by bubbling a nitrogen gas. The absorbances of extracted analytes in MIBK were directly measured by graphite furnace-AAS. The concentrations of 1,10-phenanthroline and thiocyanate ion were $2.6\;{\times}\;10^{-3}$ M and $2.3\;{\times}\;10^{-2}$ M in the mixed solution, respectively. The pH of sample solution was adjusted to 5.0 with a buffer solution and 1%(m/v) sodium lauryl sulphate solution was added as a surfactant to support the effective flotation of the complexes. The $N_2$ gas was bubbled at 30 mL/min for 90 minutes for 20 L of sample. Reproducible results of less than 10% RSD and recoveries of 80-120% could be obtained in real samples.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1085-1088
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• 2011

Heavy metal concentration as well as chemical composition were surveyed in commercial liquid pig manure to provide the basic information for mitigation research of hazardous material to agro-product. Seventy-five samples of liquid pig manure were collected and analyzed from 2009 to 2010 nationwide. Average contents of T-N, $P_2O_5$, and $K_2O$ were 0.29%, 0.08%, and 0.11%, respectively. The contents of heavy metals ranged from 0.001~0.083 for As, 0.001~0.108 for Cd, 0.002~0.495 for Cr, 0.07~47.8 for Cu, ND~0.005 for Hg, 0.035~1.033 for Ni, ND~0.291 for Pb, and $0.75{\sim}342.4mg\;L^{-1}$ for Zn, respectively. It was noted that among 75 samples, only four samples exceeded the Zn guideline ($130mg\;L^{-1}$) of liquid fertilizer derived from livestock manure but others were not exceeded the regulation.

• Journal of Soil and Groundwater Environment
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• v.27 no.6
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• pp.1-10
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• 2022

This study assessed the feasibility of iron oxide nanoparticles impregnated with biochar (INPBC), derived from woody biomass, as a stabilizing agent for the stabilization of farmland soil in the vicinity of an abandoned mine through pot experiments with 28 days of lettuce growth. The lettuce grown in the INPBC amended soils increased by more than 100% and the concentrations of inorganic elements (Cu, Ni, Zn) decreased by more than 40%. As, Cd and Pb were not transferred properly from the soils to the lettuce biomass. The bioavailability of arsenic and heavy metals in the INPBC amended soils were decreased by 26%~50%. It seems that the major mechanisms of stabilization were arsenic adsorption on iron oxides, heavy metal precipitation by soil pH increasing and heavy metal adsorption on organic matter. These results revealed that the lower bioavailability of the inorganic pollutants in the soils stabilized using INPBC induced lower transfer to the lettuce. Thus, INPBC could be used as an amendment material for the stabilization of farmland soils contaminated by arsenic and heavy metals. However, a pre-review of the chemical properties of the amended soil must be performed prior to applying INPBC in farmland soil because the concentration of the nutrients in the soil such as available phosphates and exchangeable cations (Ca, Mg, K) could be decreased due to adsorption on the surface of the iron oxides and organic matter.

• Journal of Forest and Environmental Science
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• v.40 no.3
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• pp.227-240
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• 2024

Trees improve air quality through the accumulation of air pollutants in their leaves; however, the responses of different tree species to air pollution varies. Hence, this study evaluated the responses to air pollution of selected tree species in the Swamp Forest Research Station, Onne. Ten tree species (Cola pachycarpa, Khaya grandifoliolia, Irvingia gabonensis, Garcinia kola, Chrysophyllum albidum, Treculia africana, Dacryodes edulis, Tectonia grandis, Gmelina aborea, and Nauclea diderrichii) were selected based on their abundance in the area. Leaves were collected from all sides in 3 replicates for each tree species. Laboratory analysis was carried out using standard procedures. Portable Multi Gas Detector was used to determine the concentrations of air pollutants. One-way analysis of variance was employed to test for significant difference (p≤0.05) in biochemical parameters among the tree species while Pearson's correlation was utilized to determine the level of association between different biochemical parameters and APTI; heavy metals and APTI. Results showed high concentration of PM₁₀, CO, moderate concentration of NO₂, PM_2.5, and VOC, and low concentration of ground O₃. Heavy metals - Cadmium, Mercury, Lead, Nickel and Copper were all present in the tree species at varying rates. There were significant differences in the biochemical parameters and APTI values. C. pachycarpa exhibited the highest APTI value (89.88), while D. edulis had the lowest APTI value (8.24). C. pachycarpa, K. grandifoliolia, C. albidum, G. kola, T. africana, and N. diderrichii were identified as tolerant tree species to air pollution. G. aborea, T. grandis, and I. gabonensis were considered intermediate tolerant species, while D. edulis was the only tree species sensitive to air pollution. Ascorbic Acid, Chlorophyll, Hg and Ni had positive correlations with APTI; Cd and Cu had negative association with APTI at the 0.05 significance level. C. pachycarpa, T. africana, K. grandifoliolia, C. albidum, N. diderrichii and G. kola, are recommended for planting in pollution-prone areas.

• Korean Journal of Environmental Agriculture
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• v.35 no.2
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• pp.87-96
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• 2016

BACKGROUND: The objective of this study is to evaluate the soil quality to cultivate crops in urban garden.METHODS AND RESULTS: During the period of six month from March to August 2015, measured eight heavy metals, seven Organic items and Fluorine on seventeen urban sites and thirty-one suburban sites in Gwangju city.METHODS AND RESULTS: The average concentration and range of heavy metal in soil are 0.15 mg/kg(ND-0.6) for Cd, 14.9 mg/kg(1.5-33.3) for Cu, 4.4 mg/kg(0.4-71.8) for As, 0.05 mg/kg(ND-1.366) for Hg, 24.7 mg/kg(13.1-62.7) for Pb, 102.5 mg/kg(49.1-276.4) for Zn and 9.2 mg/kg(ND-90.1) for Ni but Cr⁶⁺ is not detected. The average value and range of soil fertility items are 253.5mg/kg(76.6-1766.0) for fluorine, 6.4(4.8-7.7) for pH, 20.3 g/kg(5.0-44.0) for orangic matters, 562.7 mg/kg (28.0-1672.0) for available phosphate, 0.6 cmol⁺/kg (0.1-2.3) for K, 9.7 cmol⁺/kg (2.7-22.0) for Ca, 3.0 cmol⁺/kg (0.9-7.4) for Mg, 1.0 ds/m(0.2-2.9) for conductivity. The concentration of Hg in Suburban area is 0.005 mg/kg lower than 0.134 mg/kg in urban area. Also, the concentration of As, Cd, Ni and Zn is lower than urban area as 32%, 37%, 51%, 71% respectively.CONCLUSION: According to SPI index of soil contamination, 39 sites are first degree and 8 sites are second degree and 1 site(41th) is fourth degree. Pb and Cd are not detected and As is detected tiny amounts in plants grown polluted soil, so heavy metals have not moved to plants.