• Korean Journal of Soil Science and Fertilizer
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• v.37 no.4
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• pp.212-219
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• 2004

To minimize the danger of soil erosion and settle habitats earlier, afforestation, which vegetates bare slopes, is selected as an environmental recovering technology. Large portions of these areas often are suffered by a bad germination and growth inhibition of sprayed seeds. Afforested materials collected in the normal and damaged sites were not any big difference in chemical characteristics and biological response to ryegrass. But background soil of the damaged site has very low pH (3.6) and high contents of iron and aluminum compared with them of the normal sites. Both germination and root growth of ryegrass were inhibited severely in the water extracts of damaged soils, but not in the water extracts of normal sites. Groundwater collected nearby the damaged sites was very strong acidic (pH 33) and exhibited a high value of electrical conductivity and high contents of iron and aluminum. In the ground water, germinated ryegrass was scarcely grown. In Al standard solution, the root growth of ryegrass was inhibited over 50% in 0.5 mM in pH 3.5-4.5 and in 1.4 mM in pH 5.5, which seems to be related to $Al^{3+}$ activity in solution. In the ferric Fe ($Fe^{3+}$) standard solution, ryegrass growth was inhibited over 50% in the concentration of 14-19 mM in root and 23-25 mM in shoot. This strong tolerance of ryegrass to $Fe^{3+}$ might be concerned with the very low activity of $Fe^{3+}$ at pH 3.5-5.5. In contrast, ryegrass responded very sensitively to ferrous Fe ion ($Fe^{2+}$), especially in root growth: $Fe^{2+}$ concentrations corresponding to 50% growth reduction were 0.3-0.4 mM at pH 3.5-5.5 in roots. This high growth inhibition should be related to the high ion activity of $Fe^{2+}$ irrespective of different pH conditions. In conclusion, low pH and high contents of $Fe^{2+}$ and aluminum seem to be caused by pyrite and be closely related to the growth inhibition of ryegrass seeded in afforested area.

• Journal of Soil and Groundwater Environment
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• v.13 no.3
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• pp.52-58
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• 2008

Mn-impregnated activated carbon (Mn-AC) prepared at different conditions was applied in the treatment of synthetic wastewater containing both organic and inorganic contaminants. Phenol and As(III) was used as the representative organic and inorganic contaminants, respectively. After evaluation of the physicochemical characteristic and stability of Mn-AC, oxidation of As(III) as well as adsorption of phenol by activated carbon(AC) and Mn-AC were investigated in a batch reactor. To investigate the stability of Mn-AC, dissolution of Mn from each Mn-AC was measured pH ranging from 2 to 4. Although Mn-AC was unstable at a strong acidic condition, the dissoluted Mn was below 3 ppm at pH 4. XRD analysis of Mn-AC indicated that the mineral type of the impregnated manganese was $Mn_2O_3$. From the simultaneous treatment of As(III) and phenol by AC and Mn-AC, As(III) oxidation by Mn-AC was greater than that by AC at lower pH, while the reverse order was observed at higher pH. After impregnation of Mn onto AC, 13% decrease of the surface area was observed, causing 8% reduction of phenol removal. Considering removal properties of As(III) and phenol, Mn-AC could be applied in the simultaneous treatment of wastewater contaminated with multi-contaminants.

• Journal of Korean Society of Forest Science
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• v.11 no.1
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• pp.1-24
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• 1970

This experiment was carried out to elucidate the behavior of nutrition absorption and the acid tolerance, on varying soil pH levels, of Pinus thunbergii, Pinus densiflora, Pinus rigida, PInus koraiensis, Larix leptolepis and Abies holophylla which are 6 month old seedlings through examinations of the absorption behavior, the acid and alkali tolerance of N,P,K, Ca and Fe in the sand culture media with artificially controlled pH. 1. The increase rate of dry matter conditioned by the behavior of nutrition absorption in a strong acidic condition (pH3) was found in the following decreasing order of Pinus rigida, Pinus thunbergii. This order, therefore, can also be said to apply to the case of acid tolerance. 2. The increase rate of dry matter in a strong alkaline condition (pH9) was found in the following decreasing order of Pinus thunbergii, Pinus rigida, Pinus densiflora, Pinus koraiensis, Abies hoplohylla, Larix leptolepis. This order, therefore can be said to apply to the case of alkali tolerance. 3. Considering the absorption behavior of K and Ca, it is possible to decide the tolerance of acid from the absorption behavior and it can be said that if the absorption quantity is K>Ca the acid tolerance is strong and vice versa. 4. Considering the ratio of K:Fe and Ca:Fe in this experiment, a strong acid tolerance shows a higher ratio of K/Fe and vice versa. And also a strong acid tolerance shows a lower ratio of Ca/Fe and vice versa. It is therefore possible to decide the acid tolerance from the absorption behavior of K, Ca and Fe. 5. Of the tree species subjected to this experiment, Pinus thunbergii was the strongest in both acid and alkali tolerance. 6. In spite of that in all species the dry weight in the root is smailer than that in the top, the quantity of Fe contained in the root was larger than that in the top.

• Microbiology and Biotechnology Letters
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• v.17 no.6
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• pp.580-586
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• 1989

Penicillium sp. CB-20 was selected for strong polygalacturonase activity among various strains of molds found in soil. The optimum pH for the enzyme activity was 5.0 and optimum temperature was 4$0^{\circ}C$. The enzyme was relatively stable in acidic condition and unstable by heat treatment. The activation energy, Km and V$_{max}$ for the polygalacturonase were 2.499 Kcal/mol, 2.13$\times$10$^{-2}$mol/l, and 104.17 $\mu$mol/min. The activity of polygalacturonase was inhibited by Ag$^{+}$, Cu$^{++}$, Pb$^{++}$, Fe$^{+++}$, $Ca^{++}$, Na$^+$, Mn$^{++}$. The enzyme can be inactivated by the treatment ethylenediamintetra acetic acid, 2,4-dinitrophenol and $H_2O$$_2$. The results indicate the possible involvement of histidine, chelate and terminal amino group as active site. The enzyme was endo-type polygalacturonase.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.2
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• pp.195-200
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• 1992

Rhizopus oryzae CJ-2114 was selected for its strong polygalacturonase activity among various strains of mold found in soil. The optimum pH for the enzyme activity was 4.0 and optimum temperature was 4$0^{\circ}C$. The activation energy for the polygalacturonase was calculated by Arrhenius equation was 2.048㎉/㏖. The reaction of this enzyme followed typical Michaelis-Menten kinetics with the Km value of 54.05mM with the $V_{max}$ of 13.9m mole/min. The enzyme is relatively stable in acidic condition. The activity of polygalactur-onase was inhibited completely by C $u^{2+}$, P $b^{2+}$ and Z $n^{2+}$, $_Mn^{2+}$ at concentration of 1 mM. The enzyme can be inactivated by the treatment with maleic anhydride and iodine. The results indicate the possible involvement of histidine at active site. When polygalacturonase from Rhizopus oryzae CJ-2114 was reacted with poly-galacturonic acid as a substrate mono-, di-, and oligogalacturonic acid were produced at early and mono-, digalacturonic acid produced at late incubation time. time.

• Economic and Environmental Geology
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• v.36 no.6
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• pp.469-480
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• 2003

Laboratory leaching experiment study carried out to estimate a extent of heavy metals that could be leached out when acid rain(pH 5.0-3.0) and strong acidic solution(pH 2.5-1.0) reacted with tailings and contaminated soils from abandoned metal mines. In slightly to moderately acid conditions(pH 5.0-3.0), As, Pb and Zn dissolutions became significantly increased with decreased pH in tailing, while dissolution of these elements was very limited in contaminated soil. These results suggested that moderately acid rainwater leaches Pb, As and Zn from the tailings, while these elements would remain fixed in contaminated soil. In the pH range of 2.5-1.0(strongly acid condition), Zn, Cd and Cu concentrations of leachate rapidly increased with decreased pH in contaminated soil, while Pb, As and Co dissolutions became importantly increased in tailings. The experimental solubility of Zn. Cd and Cu was very low even at very low pH values(up to pH 1), except for CY4(Cheongyang mine). These can result from an incomplete dissolution or the presence of less soluble mineral phases. So, the solubility of heavy metals depends not only on the pH values of leachate but also on the speciation of metals associated with contaminated soils and tailings. The relative mobility of each element within failings at the pH 5.0-3.0 of the reaction solution was in the order of Pb>Zn>Cd>Co=Cu>As. In case of pH 2.5-1.0 of the reaction solution, the relative mobility of each element within contaminated soils and tailings were in the order of Zn＞Cd>Cu>Co>Pb=As for contaminated soils, and Pb>Zn>Cd>hs>Co>Cu for tailings. The obtained results could be useful for assessing the environmental effects and setting up the restoration plan in the areas.