• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2004.09a
• /
• pp.186-190
• /
• 2004

The electrokinetic bioremediation employing electrolyte circulation method was carried out for the cleanup of phenanthrene-contaminated kaolinite, and microorganism used in the biodegradation of phenanthrene was Sphingomonas sp. 3Y. The electrolyte circulation method supplied ionic nutrientsand the microorganism into soil, and inhibited the significant pH change of soil by increasing the soil buffering capacity by providing phosphate buffer compounds. When the remediation process was conducted without surfactant, the removal efficiency of phenanthrene, at the initial concentration of 200 ppm, was 69% for only 7 days. Higher microbial population and lower phenanthrene concentration were observed in the anode and middle regions of soil specimen than in the cathode region. The higher density of microorganism was because the microbial movement was in the direction of the anode part due to the negative surface charge. When Triton X-100 and APG of 20 g/1 were used to improve the bioavailability of phenanthrene strongly adsorbed onto soil surface, about 90 and 39% of phenanthrene removal were obtained. Consequently, it was confirmed that the microorganism preferred APC to phenanthrene as carbon source and so the removal efficiency with APG decreased less than that without APG.

• Korean Journal of Soil Science and Fertilizer
• /
• v.37 no.4
• /
• pp.220-227
• /
• 2004

Phosphorus desorption study is essential to understanding P behavior in agricultural and environmental soils because phosphorus is considered as two different aspects, a plant nutrient versus an environmental contaminant. This study was conducted to determine soil P buffering power related to P desorption quantity intensity (Q/I) parameters, $Q_{max}$(an index of P release capacity) and $l_0$(an index of the intensity factor), and to investigate the characteristics of relationship between the P desorption Q/I parameters and the soil properties. Soil samples were prepared with treatments of 0 and $100mg\;P\;kg^{-1}$ applied as $KH_2PO_4$ solution. The P desorption Q/I curves were obtained by a procedure using anion exchange resin beads and described by an empirical equation ($Q=aI^{-1}+bln(I+1)+c$). The P desorption Q/I curves for the high available P (${\g}20mg\;kg^{-1}$ of Olsen P) soils were characteristic concave trends with or without soil P enrichment, whereas for the low available P (${\lt}20mg\;kg^{-1}$ of Olsen P) soils, the anticipated Q/I concave curves could not be obtained without a proper amount of P addition. When the soils were enriched in phosphates, the values of desorbed solid phase labile P and solution P, such as $Q_{max}$ and $I_0$ respectively, were increased, but the ratio of $Q_{max}$ versus $I_0$ was decreased. Thus, the slope of desorption Q/I curve represented as phosphorus buffering power, $|BP_0|$, is decreased. The $|BP_0|$ values of the high available P soils ranged between 48 and $61L\;kg^{-1}$ in the P untreated samples and between 18 and $44L\;kg^{-1}$ in the P enriched samples. Overall $|BP_0|$ values of both low and high available P soils treated with $l00mg\;P\;kg^{-1}$ ranged between 14 and $79L\;kg^{-1}$. The $Q_{max}$, values ranged between 71.4 and $173.1mg\;P\;kg^{-1}$, and the lo values ranged between 0.98 and $3.82mg\;P\;L^{-1}$ in the P enriched soils. The $Q_{max}$ and $I_0$ values that control the P buffering power may be not specifically related to a specific soil property, but those values were complicatedly related to soil pH, clay content, soil organic matter content, and lime. Also, phosphorus release activity, however, markedly depended on the desorbability of the applied P as well as the native labile P.

• Korean Journal of Soil Science and Fertilizer
• /
• v.37 no.2
• /
• pp.59-65
• /
• 2004

Interactions of phosphorus and zinc in soils are important to determine the availability of the elements because those elements are closely related in the agricultural environment. The objective of this study was to investigate the interactions of P and Zn using desorption quantity (Q)-intensily(I) isotherms. Physically and chemically different soils, acidic Egan, acidic sandy Egeland, calcareous Glenham, and neutral Maddock, were used. The soils were enriched with different concentrations of P and Zn as $KH_2PO_4$ and $ZnSO_4$ solutions, respectively. Zinc enrichments affected availability of P in the Egan soil, which contained higher amounts of clay, organic matter, and exchangeable Fe than the other soils tested. After Zn enrichments, the pH drastically decreased in Egeland sandy soil, not changed in the calcarious Glenham soil, and slightly decreased in Egan and Maddock soil systems. The values of $Q_{max}$ and $I_0$ of phosphorus decreased with increasing Zn concentrations enriched in all soils, the changes of those values did not influence the P buffering power, |$BP_o$| values, in most soils. The influences of P treatment on Zn availability were varied. The values of Zn buffering capacity, $BC_{Zn}$, were lowest in the Egeland soil that had the lowest soil pH, amounts of clay minerals, organic matter, CEC, and exchangeable Fe, and were highest in the calcareous Glenham soil. The $BC_{Zn}$ values ranged from 202 to 4480. With P application, the changes of $BC_{Zn}$ values were more affected by the changes of soil solution Zn contents (I) than the changes of DTPA extractable Zn contents(Q). The change of Q and I values was found to be dependent upon soil properties, especially, soil pH.

• The Korean Journal of Ecology
• /
• v.13 no.2
• /
• pp.131-142
• /
• 1990

From July 1, 1985 to June 30, pH values of precipitation in Seoul area were average 5.1 and acid rain which was lower than pH 5.5 showed a frequence of 70.7%. Seasonal changes appeared in pH values of annual precipitation in Seoul. The pH patterns of spring and autumn were generally less acid than that of summer and winter, and snowfall pH was lower than rainfall. The beginning rainfall in Seoul was neutral because of alkali dust in the atmosphere. As times went on, rainfall pH was gradually low and after 1 to 2 hours, showed a steady state. On the surface soil precipitation was neutralized by soil buffering capacity.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2003.04a
• /
• pp.455-458
• /
• 2003

We investigated the leaching of elements from anthracite ashes by interactions with seawater. The results show that consumption rates of dissolved oxygen are 7.5 times greater in the seawater system than in the fresh water system and indicate that the differences in DO consumption rate may plat a role in regulating the element leaching from the coal ashes. It is revealed that seawater's pH buffering capacity is the most important factor that makes the leaching of elements and their chemical behaviors in the seawater system different from those in the fresh water environments. In overall, element leaching from the weathered ash is smaller than that from the fresh ash. However, the leaching of Si, Fe, Al, Mn, phosphate, and some other elements were independent of weathering. They were dependant only on the pH of the solutions.

• Journal of Environmental Impact Assessment
• /
• v.32 no.2
• /
• pp.112-122
• /
• 2023

To restore the ecological function of contaminated soil and maximize the ecological services provided by the soil, besides the toxicity orrisk caused by pollutants, the functional aspects of the soil ecosystem should be considered. In this study, a method for evaluating the health of cleaned soil was presented, and the applicability of the proposed evaluation method was examined by applying it to soil treated with washing and landfarming. Productivity, habitat, water retention capacity, nutrient cycling, carbon retention capacity, and buffering capacity were used as soil health evaluation indicators. The results showed that the soil health was not completely recovered after remediation, and even in the case of the washed soil, the health was lower than before remediation. On the other hand, there was no significant change in soil quality due to oil pollution, but soil health deteriorated. Unlike the slightly improved soil quality after landfarming treatment, soil health was not completely restored. Therefore, the results of this study indicate that it is desirable to consider both soil quality and health when evaluating the remediation effect. The soil health evaluation method proposed in this study can be usefully utilized for the sustainable use of cleaned soil and to promote ecosystem services.

• Journal of Soil and Groundwater Environment
• /
• v.23 no.2
• /
• pp.23-29
• /
• 2018

This study explored secondary effects of the residual hydrofluoric acid (HF) after a hypothetical acid spill accident by investigating the long-term dissolution of minerals and leaching of pre-existing arsenic (As) from two soil samples (i.e., KBS and KBM) through batch and column experiments. An increase in the HF concentration in both soil samples resulted in a dramatic increase in the release of major cations, especially Si. However, the amounts of mineral dissolved were dependent on the soil type and mineral characteristics. Compared to the KBM soil, relatively more Ca, Mg and Si were dissolved from the KBS soil. The column experiment showed that the long-term dissolution rates of the minerals are closely associated with the acid buffering capacity of the two soils. The KBM soil had relatively higher effluent pH values compared to the KBS soil. Also, more As was leached from the KBM soil, with a more amorphous hydrous oxide-bound As fraction. These results suggest that the potential of heavy metal leaching by the residual acid after an acid spill will be influenced by heavy metal speciation and mineral structure in the affected soil.

• Journal of Soil and Groundwater Environment
• /
• v.22 no.6
• /
• pp.1-11
• /
• 2017

This study was conducted to investigate the performance of four commercial chemical agents in stabilizing arsenic (As) in soil at the forest area near the former Janghang smelter site. After amending the stabilizing agents (A, B, C, and D) into As-contaminated soil samples, synthetic precipitation leaching procedure (SPLP) and solubility bioavailability research consortium (SBRC)-extractable As concentrations significantly decreased except for agent D, which is mainly composed of fly ash and calcium carbonate. Increase of SPLP and SBRC-extractable As concentrations in four soil samples (S1, S2, S3, and J2) was attributed to desorption of As adsorbed on iron oxides due to high pH generated by agent D. It is therefore necessary to consider application conditions according to soil characteristics such as pH and buffering capacity. Results of sequential extraction showed that readily extractable fractions of As in soil (i.e., sum of $SO_4-$ and $PO_4-extractable$ As in soil) were converted into non-readily extractable fractions by amending agents A, B, and C. Such changes in the As distribution in soil resulted in the decrease of SPLP and SBRC-extractable As concentration. A series of follow-up monitoring and management plan has been suggested to assess the longevity of the stabilization treatments in the site.

• Journal of Soil and Groundwater Environment
• /
• v.26 no.6
• /
• pp.65-73
• /
• 2021

Since the amount of red mud, generated from aluminum smelting process as a by-product, has increased worldwide, the recycle and metal resource recovery from the red mud is becoming more important. In this study, in order to recycle the red mud as a soil stabilizer to remediate arsenic contaminated soils, neutralization of red mud was investigated. Red mud was neutralized by washing with distilled water and NaCl, CaCl₂, FeCl₃, and HCl solutions and heating at 200-800℃, and arsenic stabilization characteristics in soils were evaluated with the neutralized red mud. Although washing with distilled water was not effective in neutralizing red mud, the application of the washed red mud to soils lowered the soil pH compared to the application of untreated red mud. Among NaCl, CaCl₂, FeCl₃, and HCl solutions, washing with FeCl₃ showed the most effective in lowering pH of the red mud from pH 10.73 to pH 4.26. Application of the neutralized red mud in soils resulted in quite different arsenic stabilization efficiency depending on soil samples. In M1 soil, which showed relatively high arsenic stabilization efficiency by untreated red mud, the neutralization of red mud resulted in little effect on arsenic stabilization in soil. On the other hand, in M2 soil, which showed low arsenic stabilization efficiency by untreated red mud, the neutralization of red mud increased arsenic stabilization significantly. Soil characteristics such as clay minerals and pH buffering capacity seemed to affect reactions between red mud and soils, which resulted in different effects of the red mud application on soil pH and arsenic stabilization efficiencies.

• Journal of Environmental Science International
• /
• v.7 no.2
• /
• pp.149-156
• /
• 1998

Enoronmental problems caused by certain geologic conditions Include pollution of soil by heavy metal, acidization of souls , acid mine drainage, Pound-water pollution, and natural radioactivity, as well as zoo-logical hazards such as landslide and subsidence. The acrid mine drainage contains large amount of heavy metals nO, therefore. cause serious pollution onto the nearby drainage systems and soils. In spite of this prospective environmental danger, few studies have been done on the acid mine drainage derived from non-metallic ore deposits such as pyrophyllitefNapseok) deposits. The sudo-bearing pyrophyllite ores, alteration zones, and mine talllngs of pyrophylllte deposits produce acrid mine drainage by the okidation of weathering. Compared to the fresh host rocks, the ores and altered rocks of pyrophyllite deposits produce acidic solution which contain higher amount of heavy metals because of OeP lower buffering capacity to acrid solution. The pus of urine water and nearby stream water of pyrophyllite deposits are 2.1~3.7, which are strong- ly acidic and much lower than that (6.2~7.2) of upstream water and than that (6.8~7.6) of the stream water derived from the non-mineralized area. This study reveals that this acrid mine drainage can affect the downstream area which is 8km far from the pyrophyllite deposits, even though the drain Is diluted with abundant non-contaminated river water This suggmists that not only acid mine drainage but also the sulfide-bearing sediments originated from the pyrophyllite deposits move downstream and form acidic water through continuous oxidation reaction. The heavy metals such as Pb, Zn, Cu, Cd, Nl, Mn and Fe are enriched In the mine water of low pH, and their contents decrease as the pH of mine water Increases because of the Influx of fresh stream wainer. SoUs of the Pyrophyulte deposits are characterized by high contents of heavy metals. The stream sediments containing the yellowish brown precipitates formed by neutralization of acid mine drainage occur in all parts of the stream derived from the pyrophyllite deposits, and the sediments also contain high amounts of heavy metals. In summary, the acid mine drainage of the pyrophyllite deposits is located in the upstream part of Hoidong water reservoir in Pusan contains large amounts of heavy metals and flows into the Holdong water reservoir without any purification process. To protect the water of Holdong reservoir, the acid mine drainage should be treated with a proper purification process.