• Korean Journal of Soil Science and Fertilizer
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• v.30 no.1
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• pp.72-83
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• 1997

Forty six natural habitats of Korean lespedeza(Leapedeza stipulacea Maxim.) were investigated for the growth characteristics, mineral contents of plant and the physico-chemical properties of natural habitat's soil compared with the upland soil nearby the habitat. The results obtained were summarized as follows. Plant height and dry matter yield were higher in the samples taken in late than early August showing large variation within the sampling date and location. Korean lespedeza showed higher contents of Fe and Mn, but lower contents of K, Ca, Mg and Cu than Alfalfa. The contents of P and Zn were about the same. The natural habitat showed higher soil pH and Ca content but lower contents of $P_2O_5$, K, and organic matter than the vicinity of natural habitats and the average soil of Korea. The contents of Mg were about the same. The soil texture of natural habitats showed much higher portion of sand and extremely low portions of silt and clay than both area. Korean lespedeza is so well adapted to the soil with low fertilizer and organic matter that other crops and most weeds fail. It also appears to thrive on the sandy loams, loamy sands of the piedmont region such as waste land and on the similar soils with variously physico-chemical properties.

• Journal of Environmental Impact Assessment
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• v.32 no.3
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• pp.157-165
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• 2023

In Korea, a major contaminant of farmland soils in the vicinity of abandoned mines is arsenic, for which the general soil reclamation method is contaminated soil stabilization and cover the stabilized soil with clean soil at a thickness of 40 cm. In a previous pot experiment study we confirmed the feasibility of a lower thickness (20 cm) of covering soil for such reclamation in abandoned coal mines, where arsenic contamination levels are generally lower than in metal mines. In this subsequent study a field experiment including rice plant cultivation in field test plots was conducted. For over 4 months, the transfer of arsenic from the contaminated soil to the unpolished rice grains was reduced by 44% when a clean soil covering with a thickness of 20 cm was applied. The maximum decrease (56%) was shown when the stabilization process was performed before the covering. These results reveal a lower thickness of clean soil covering has a high feasibility and it can increase cost-efficiency in the reclamation of an abandoned coal mine.

• Economic and Environmental Geology
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• v.57 no.3
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• pp.305-317
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• 2024

To investigate the effect of changes in microbial communities on arsenic release in soil, experiments were conducted on arsenic-contaminated soils (F1, G7, and G10). The experiments involved three groups of the experimental sets; ① BAC: sterilized soil + Bacillus fungorum, ② IND: indigenous bacteria, and ③ MIX: indigenous bacteria + B. fungorum, and incubated them for seven weeks using lactate as a carbon source under anaerobic conditions. The experimental results showed that higher concentrations of arsenic were released from the IND and MIX soils, where indigenous bacterial communities existed, compared to BAC. Significantly higher levels of arsenic were released from the G10 soil, which showed higher pH, compared to the F1 and G7 soils. In the G10 soil, unlike other soils, the proportion of As(III) among the released arsenic was also low. These results may be attributed to differences in microbial community composition that vary depending on the soil. By the seventh week, the diversity of microbial species in the IND and MIX soils had significantly decreased, with dominant orders such as Eubacteriales and Bacillales thriving. Bacteroidales in the seventh week of the MIX in the F1 soil, Rummeliibacillus in the seventh week of the IND and MIX of the G7 soil, and Enterobacterales in the IND and MIX of the G10 soil were dominant. At present, it is not known which mechanisms of microbial community changes affect the geochemical behavior of arsenic; however, these results indicate that microbiome in the soil may function as one of the factors regulating arsenic release.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.64-65
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• 2016

This study that prevent cancer using absorbent to inflow Radon gas in the room existing soil and rock is making board to absorb the Radon gas as a fundamental study. So, we use bentonite as a absorbent. So, we use bentonite as a absorbent. Bentonite is a 'clay mineral' composed to montmorillonite of main component that volcanic ash denatured to a clay mineral. Bentonite has fine microparticle of nano level, abundant mineral 66 of kinds, adsorbability, swelling, a positive ion(heavy metal adsorption reaction) as a bentonite's property. Using magnesia cement for oxide of magnesiuma and magnesium chloride as a main binder, we measure Radon gas absorbent efficiency and thermal conductivity.

• Economic and Environmental Geology
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• v.44 no.1
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• pp.37-48
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• 2011

Some industrial minerals used in domestic industries such as monazite, apatite, bauxite, and ilmenite belong to NORM (Naturally Occurring Radioactive Materials) because they show a high radioactivity. Products, semi-products, wastes, and by-products which show higher radioactivity than NORM belong to TENORM (Technologically Enhanced Naturally Occurring Radioactive Materials). Apatite used for manufacturing phosphate fertilizer in Namhae Chemical company belongs to NORM, and its by-product, phospo-gypsum, belongs to TENORM. A geological investigation is needed for the future environmental impact assessment of the Namhae Chemical company's site. According to survey results of the Namhae Chemical company's site, soil mineral composition indicated the mixture of minerals derived from the country rock (quartz, feldspar, mica, $l4{\AA}$ mineral, kaolin and amphibole) and minerals from the gypsum open-air storage yard (gypsum and apatite). Soil samples showed average content of U 4.6 ppm and Th 10 ppm, which are similar to average crustal abundances. They also show average contents of $^{40}K$ 191-1,166 Bq/kg, $^{226}Ra$ 15.6-710 Bq/kg, and $^{232}Th$ 17.4-72.7 Bq/kg, which indicate moderate levels of radio nuclide. But $^{226}Ra$ anomaly in the gypsum open storage yard is clearly confirmed and $^{232}Th$ anomaly is also confirmed in the east road side of the factory and nearby mountain areas. Soil external hazard indices ranged 0.24-2.01 with the average 0.54. Although most external hazard indices were lower than 1, which means radiation hazard index to be negligible, 5 samples out of total 40 samples showed higher values than 1, and further detailed investigation is needed.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.182-186
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• 2001

An acid forest surface soil as a land farming medium was treated with a water plant alum sludge at 0 to 18%. Indian mustard was grown in the treated soil in a greenhouse for 5 weeks and watered with pH 4 tap water adjusted with a mixed acid (1HNO$_3$: 2H$_2$SO$_4$) during plant growth. Changes in soil property, leachate chemistry, plant growth, and plant uptake of elements by the sludge treatment were determined. The alum sludge treatment increased buffer capacity to acidity, hydraulic conductivity, water holding capacity, and phosphate adsorption of the soil and decreased bulk density and mobility of small particles. The sludge treatment reduced leaching of Al, Mg, K, Na, and root elongation. Plant did uptake less amount of the cations and P but more Ca with the sludge treatment.

• Economic and Environmental Geology
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• v.25 no.2
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• pp.145-151
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• 1992

In order to study the optimum depth for the soil geochemical exploration in the area which is affected by agricultural activities and waste disposal of metal mine, the soil samples were sampled from the B layer of residual soil and vertical 7 layers up to 250 cm in the rice field and 3 layers up to 90 cm in the ordinary field. They were analyzed for Au, As, Cu, Pb and Zn by AAS, AAS-graphite furnace and ICP. To investigate the proper depth for the soil sampling in the contaminated area, the data were treated statistically by applying correlation coefficient, factor analysis and trend analysis. It is conclude that soil geochemical exploration method could be applied in the farm-land and a little contaminated area. The optimum depth of soil sampling is 60 cm in the ordinary field, and 150~200 cm in the rice field. Soil sampling in the area of a huge mine waste disposal is not recommendable. Plotting of geochemical map with factor scores as a input data shows a clear pattern compared with the map of indicater element such as As or Au. The second or third degree trend surface analysis is effective in inferring the continuity of vein in the area where the outcrop is invisible.

• Geomechanics and Engineering
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• v.21 no.4
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• pp.337-348
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• 2020

Tropical organic soils having more than 65% of organic matters are named "peat". This soil type is extremely soft, unconsolidated, and possesses low shear strength and stiffness. Different conventional and industrial binders (e.g., lime or Portland cement) are used widely for stabilisation of organic soils. However, due to many factors affecting the behaviour of these soils (e.g., high moisture content, fewer mineral particles, and acidic media), the efficiency of the conventional binders is low and/or cost-intensive. This research investigates the impact of different constituents of cement-sodium silicate grout system on the compressibility behaviour of organic soil, including settlement and void ratio. A microstructure analysis is also carried out on treated organic soil using Scanning Electron Micrographs (SEM), Energy Dispersive X-ray spectrometer (EDX), and X-ray Diffraction (XRD). The results indicate that the settlement and void ratio of treated organic soils decrease gradually with the increase of cement and kaolinite contents, as well as sodium silicate until an optimum value of 2.5% of the wet soil weight. The microstructure analysis also demonstrates that with the increase of cement, kaolinite and sodium silicate, the void ratio and porosity of treated soil particles decrease, leading to an increase in the soil density by the hydration, pozzolanic, and polymerisation processes. This research contributes an extra useful knowledge to the stabilisation of organic soils and upgrading such problematic soils closer to the non-problematic soils for geotechnical applications such as deep mixing.

• Korean Journal of Plant Resources
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• v.35 no.6
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• pp.762-769
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• 2022

Growth characters and ingredient contents of two-year-old bellflower (Platycodon grandiflorum) roots were investigated under both control and soil moisture treatment condition using soil moisture control system including soil sensing and automatic water supply chain in this study. Root diameter, fine root number, root length, fresh weight and dry weight of the plant were significantly influenced by the automatic water treatment, 20%, 30%, 40% and 50%, respectively. Ingredient contents of the two-year-old roots in bellflower plants were detected in the 20% and 50% of controlled soil moisture content. Contents of amino acids were decreased by the soil moisture treatment, meanwhile, contents of minerals were not showed significant decrease except for phosphorus content. Showing no difference in proline and tyrosine, fourteen of the amino acid contents were gradually decreased by the increased soil moisture contents, with significant decrease in serine, glycine, alanine, leucine, lysine and histidine at 20% treatment.

• Resources Recycling
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• v.20 no.3
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• pp.28-39
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• 2011

This review investigated theoretical principals and practical application examples on recirculation system of soil washing-wastewater treatment-treated water recycling. As for technologies which have attempted to remediating metals-contaminated soil in and around country, there are reactive barriers, encapsulation, solidification/stabilization, soil washing, and phytoremediation. Among those, in particular, this review covers soil washing technology which physicochemically removes contaminants from soils. The major drawbacks of this technology are to generate a large amount of wastewater which contains contaminants complexed with ligands of washing solution and needs additional treatment process. To solve these problems, many chemical treatment methods have been developed as follows: precipitation/coprecipitation, membrane filtration, adsorption treatment, ion exchange, and electrokinetic treatment. In the last part of the review, recent research and field application cases on soil washing wastewater treatment and recycling were introduced. Based on these integrated technologies, it could be achieved to solve the problem of soil washing wastewater and to enhance cost effective process by reducing total water resources use in soil washing process.