• Animal cells and systems
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• v.7 no.4
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• pp.289-294
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• 2003

To quantify nutrient loading from emergent macrophytes through leaching in the littoral zones of Paldang Reservoir, we conducted incubation experiments using leaf litter of the emergent macrophyte, Zizaniz latifolia. To separate the leaching process from microbial decay, we used $HgCl_2$ to suppress microbial activity during the experiment. We measured electric conductivity, absorbance at 280nm, total nitrogen and dissolved inorganic nitrogen, total phosphorus and soluble reactive phosphorus, Na, K, Mg and Ca amounts in leaf litter and in water. In addition, we examined the effects of water temperature and ion concentrations of ambient water on the leaching process. A total of 6% of the initial ash-free dry mass of leaf litter was lost due to leaching during incubation (four days). Electric conductivity and A280 continued to increase and saturate during the incubation. To compare reaching rates of different nutrients, we fitted leaching dynamics with a hyperbolic saturation function [Y=AㆍX/(B+X)]. From these fittings, we found that ratios of leaching amounts to nutrient concentration in the litter were in the order of K > Na > Mg > P > Ca > N. Leaching from leaf litter of Z. latifolia was dependent on water temperature while it was not related with ion concentrations in the ambient water. Our results suggest that the leaching process of nutrients, especially phosphorus, from aquatic macrophytes provides considerable contribution to the eutrophication of the Paldang Reservoir ecosystem.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.7
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• pp.1357-1364
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• 2000

Our study was performed to evaluate the effect of leaching parameters including the physicochemical characteristics and the fractionated composition of heavy metals on the release of heavy metals in fly ash discharged from MSWI. Leaching parameters such as pH, CEC, particle size, and exchangeable fraction among the fractional composition classified by sequential extraction procedure are considered. The leaching rate of heavy metal released by KSLT method is largely dependent on the pH of fly ash. The effect of pH on the release of heavy metals is different from elements. It appears that the leaching rate of cadmium and copper decreases with increasing pH, while lead and zinc increases at the condition of neutral or strong alkali condition, which suggests that the leaching of heavy metals are limited by the solubility. It is found that the effect of CEC is similarly to that of pH, $D_{10}$ among the particle size of fly ash is negative correlated with the concentration of heavy metals leached by KSLT method. In the case of exchangeable fraction, the leaching rate of heavy metals is linearly correlated with the exchangeable fraction for the fly ash below 40 meq/l00g of CEC, but not related out of the range.

• Asian Journal of Turfgrass Science
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• v.20 no.1
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• pp.47-55
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• 2006

Golf course community has always been concerned about water quality regarding to pesticide and fertilizer managements. This study conducted to investigate sorption and leaching behavior of common pesticides used for golf course in granular activated carbon I (GAC 1), granular activated carbon II(GAC II), and charcoal. We used batch study to investigate the influence of concentrations of Smithion and Folicur and particle sizes of GAC I, GAC II, and charcoal on sorption. Also, column study was used to investigate the leaching effect of Smithion in GAC I and charcoal. We found that sorption of Smithion and Folicur were higher in less $45{\mu}m$ of particle size for GAC I, GAC II, and charcoal compared to $1.7{\sim}2.0mm$ size, and the sorption of Smithion and Folicur in less $45{\mu}m$ of particle size ranged from 90 to 99%. In the column study, there was no difference in leaching effect between GAC I and charcoal. Overall, we found that charcoal might offer a cost effective adsorbent as a pesticides in leachate.

• Analytical Science and Technology
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• v.11 no.5
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• pp.394-399
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• 1998

This study was carried out to characterize the chemical composition and leaching properties of heavy metals in coal fly ash, which was generated from Korean electrical power utilities in several million tons per year. Comparion with respect to the leachability of heavy metals between the Korea standard leaching test (KSLT) and the American Environment Protection Agency (EPA) method 1311 (TCLP: Toxicity Chracteristic Leaching Procedure) was performed. The concentration of Ag, As, Ba, Cd, Cr, Cu, Pb, Se, Hg in the leacheate was determined by ICP-MS. The analytical result showed a significant difference of the leachability according to the characteristics of the leaching solution except Se, suggesting the necessity of improvement in the leaching test method that is currently implemented in Korea.

• The Korean Journal of Pesticide Science
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• v.17 no.3
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• pp.168-177
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• 2013

This experiment was carried out to estimate leaching potential of thirteen endocrine disruptor-suspected pesticides in upland soils using soil columns (5 cm I.D. ${\times}$ 35 cm H.) packed with soil A (sandy loam) and soil B (loam). When 12.6 mL of water, average precipitation in Cheongju area during the period from June to August, 2001-2010, was percolated through soil column packed with soil A every day for 21 days, no pesticides were detected from leachate, with the exception of metribuzin which was detected with negligible. Also, when 2 L of water was percolated consecutively five times through soil columns packed with soil A and B, irrespective of soil types, cypermethrin, endosulfan, fenvalerate, parathion and trifluralin, which were very low water solubilities and high soil $K_{oc}s$, were not detected from leachate and were distributed mostly in the depth of 0-5 cm, representing that water solubility and soil $K_{oc}$ are major contributing factors to their leaching behavior. Despite high average leaching rates in carbaryl and methomyl, actual possibilities of ground water contamination in the agricultural environment by them would be very low, considering that the negligible amount of pesticide was percolated through a lysimeter with an undisturbed soil core simulating the field conditions, while most of pesticide was percolated through a soil column with the disturbed soil profile.

• Journal of Microbiology and Biotechnology
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• v.13 no.3
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• pp.323-331
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• 2003

Bacteria and fungi are fundamental biotic components of natural biogeochemical cycles for metals and metalloids, and play important roles in dissolution, precipitation, oxidation and reduction processes. Some processes catalyzed by microorganisms also have important applications in environmental biotechnology in the areas of ore leaching and bioremediation.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.1
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• pp.64-71
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• 2015

Soil contamination with arsenic and heavy metals is a worldwide problem. Main objective of this research was to evaluated effects of reducing heavy metal leaching under reduced soil condition amended with industrial by-products. The contaminated soil was amended with 3% (w/w) of limestone (Ls), steel slag (SS) and acid mine drainage sludge (AMDS). Synthetic acid rain ($H_2SO_4:HNO_3=6:4$, pH 5.5 fixed) was used for feeding solution with flow rate of $0.78{\sim}0.88mL\;min^{-1}$. Results showed that similar pH and EC of leachate was observed in all treatments regardless of applied industrial by-products. However, arsenic concentration of leachate increased when industrial by-products were mixed. Meanwhile, concentration of heavy metal in the leachate decreased from 11.3 to 4.59 mg for Cd, from 92.3 to 7.93 mg for Pb, and from 11,716 to 1,788 mg for Zn via immobilization in soil with AMDS amended, respectively. Overall, application of industrial by-products can be an environmentally-friendly way to remediate soil and(or) leachate contaminated with metal(loid)s in metal mine site.

• Journal of Soil and Groundwater Environment
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• v.10 no.3
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• pp.1-8
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• 2005

Fractional compositions and leaching potentials of Cd, Cu and Zn were investigated in the soils which had been disposed with the metal processing wastes, tungsten mine tailings and low quality coal mine area. Total concentrations of metals in these soils were higher than in non-polluted paddy and upland soils. Fractions of Cd, Cu and Zn were mostly reducible, organic and residual forms, but varied with origins of wastes. Residual fraction was a predominant form in the nonpolluted soils. Leaching potentials of metals were higher in polluted soils than in non-polluted soils. Metals leached were higher at pH 4.0 than 7.0 and increased with the duration time. After 25 to 35 hrs, metals released from soils reached a pseudoequilibrium. Leaching potential of metals in non-polluted soils was low due to high percentage of residual fractions.

• Korean Journal of Environmental Agriculture
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• v.24 no.2
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• pp.132-138
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• 2005

Objective of this research was to evaluate the fate of nitrogen and phosphorous in hydroponic waste solution from the plastic film house cultivation applied to the upland soil by column leaching and field experiment. The pH and EC of leachate were decreased by the reaction with the upland soil in the column leaching experiment. The EC and concentrations of $H^+,\;K^+,\;and\;{NH_4}^+$ of leachate were decreased as the column length (soil depth) was increased. But these were increased as the amounts of the hydroponic waste solution were increased field experiment growing red pepper (Capsicum annum L.) to monitor the nutrients movement using ion exchange resin capsule demonstrated that the nutrient concentration of soil solution was increased in the orders of $PO_4-P. Nitrate concentration of resin capsule inserted into the soil was relatively higher than other nutrients $(NH_4-N\;and\;PO_4-P)$ at the 45 cm of soil depth. The overall results demonstrated that the hydroponic waste solution could be recycled as plant nutrients to enhance fertility of soils. But nitrate leaching was a major factor for safe use of the hydroponic waste solution in soil.

• Journal of Applied Biological Chemistry
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• v.65 no.4
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• pp.421-427
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• 2022

In this study, Jeju Tatary buckwheat tea's chemical composition and physiological activities were compared according to the leaching temperature (60, 80, 100 ℃). As the leaching temperature is increased, the degree of browning is induced. However, there was no significant change in pH. The total polyphenol content was higher at 80 ℃ than at 60 ℃ leaching temperature, but significantly decreased at 100 ℃ leaching temperature (60 ℃: 17.06 mg GA/g, 80 ℃: 20.09 mg GA/g, 100 ℃ :18.45 mg GA/g). There were high content of flavonoid and rutin as the leaching temperature increased. Consistently, 2,2-diphenyl1-picrylhydrazyl (DPPH) radical scavenging activity and tyrosinase inhibitory activity were significantly higher with increasing temperature (DPPH % inhibition: 60 ℃: 41.88%, 80 ℃: 46.01%, 100 ℃: 46.80%/tyrosinase inhibitory activity: 60 ℃: 9.38%, 80 ℃: 22.94%, 100 ℃: 28.17%). However, there was no significant difference in DPPH radical scavenging activity between 80 and 100 ℃. A cytotoxicity test was performed by treating with Jeju Tatary buckwheat extract into mouse macrophage cells (Raw264.7). 100 and 200 ㎍/mL treatment (100 ℃ extract) were significantly upregulated the survival rate, but there was no significant difference in other concentrations. Collectively, most of the bioactive components, antioxidant activity, and tyrosinase inhibitory activity were induced as the leaching temperature increased. However, the content of polyphenols which are known to have antioxidant activity, was significantly reduced at 100 ℃ leaching temperature. Several reports have demonstrated that leaching at too high temperature lowered the overall acceptability, so the optimal leaching condition of Tatary Buckwheat is 80 ℃, 5 min in this study.