• 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.

• Economic and Environmental Geology
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• v.33 no.5
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• pp.379-389
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• 2000

This study was focused on the investigation for the heavy metal contamination of soils derived from Yoecheon Industrial Complex in Chonnam Province. Total 201 soil samples including farmland, paddy, forest and playground soils were collected, extracted by 0.1N HCl and analyzed for Cd, Cu, Cr, Fe, Mn and Zn using AAS. Most pH values in soils were weak acidic ranges of 4-6, while some of them were over 8.0. Concentrations of Cd, Cu, Fe and Zn in the soils tend to be relatively high around the Au-Ag mine area, railroad stations and oil station, however, those of Cr, Mn and Pb show high at the northside of Pohang Steel Co (POSCO). Cadmium-Zn couples, and Cd-Zn and Zn-Cr couples have relatively good correlations in the farmland soils and paddy soils, respectively. Concentrations of Cd, Fe and Zn with depth tend to be higher in the top soils than in the bottom soils, but those of Cu and Pb do not show regular variations with depth.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.544-547
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• 2003

The objective of this study is to investigate the contamination levels and dispersion patterns of arsenic and heavy metals and to estimate the bioaccessible fraction of the metals in soil and plant samples in the vicinity of the abandoned Songcheon Au-Ag mine. Tailings, soils, plants (Chinese cabbage, red pepper, soybean, radish, sesame leaves, green onion, lettuce, potato leaves, angelica and groundsel) and waters were collected around the mine site. After appropriate preparation, all samples were analyzed for As, Cd, Cu, Pb and Zn by ICP-AES and ICP-MS. Elevated levels of As and heavy metals were found in tailings. Mean concentrations of As in agricultural soils were higher than the permissible level. Especially, maximum level of As in farmland soil was 513 mg/kg. The highest concentrations of As and Zn were found in Chinese cabbage (6.7 mg/kg and 359 mg/kg, respectively). Concentrations of As, Cd, and Zn in most stream waters which are used for drinking water around this mine area were higher than the permissible levels regulated in Korea. Maximum levels of As, Cd and Zn in stream waters were 0.78 mg/L, 0.19 mg/L and 5.4 mg/L, respectively. These results indicate that mine tailings can be the main contamination sources of As and heavy metals in the soil-water system in the mine area. The average of estimated bioaccessible fraction of As in farmland soils were $3.7\%$ (in simulated stomach) and $10.8\%$ (in simulated small intestine). The highest value of bioaccessible fraction of metal in farmland soils was $46.5\%$ for Cd.

• Economic and Environmental Geology
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• v.40 no.1 s.182
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• pp.15-28
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• 2007

The study is for contaminations of major, rare earth and trace elements of the farmland soils from the Boeunjeil mine area. The results are compared with the soils of Chungjoo, Deokpyeong, Boeun and Chubu areas. Fe and S contents of the contaminated area are high relative to those from the uncontaminated areas, Chungjoo and Boeun areas. Trace elements of the contaminated area are high relative to those from uncontaminated area, Chunajoo, Deokpyeong, Boeun and Chubu areas. The trace elements ares divided into Cd, Ni, Sr, U, V, Zn and As, Co, Cu, Mo, Pb, Sb, based on these dispersion and correlation. Two groups show the positive correlation. Enrichment factor of potentially toxic elements from contaminated area is >5 value, but <4 value in the uncontaminated area. In the geoaccumulation index of the minor elements, the contaminated area has >1 value and the uncontaminated area has <1 value except Mn. Enrichment index of potentially toxic elements(As, Cd, Co, Cu, Ni, U, Zn) ranges from 0.3 to 87.0 in the contaminated area and from 0.4 to 3.9 in the uncontaminated area. Overall results show that the high contents of farmland soils for the elements(Fe, S, As, Cd, Co, Cu, Ni, U, Zn) indicate the contamination by coal-related activities.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.1
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• pp.118-126
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• 2012

Korea's agriculture had many inherent problems. Korea is a mountainous country with only 22 percent farmland and less rainfall than most other neighboring rice-growing countries. A major land reform in the late 1940s and early 1950s spread ownership of land to the rural peasantry. Individual holdings, however, were too small or too spread out to provide families with much chance to produce a significant quantity of food. The enormous growth of urban areas led to a rapid decrease of available farmland, while at the same time population increases and bigger incomes meant that the demand for food greatly outstripped supply. The result of these developments was that by the late 1980s roughly half of Korea's needs, mainly wheat and animal feed corn, was imported. Korea's agriculture is facing a new round of difficulties from the inevitable process of market opening. Therefore, we have reviewed the agricultural status and soils in Korea how we can meet the coming issues with respect to production and prospect based on the government documents and articles published on the journals.

• Economic and Environmental Geology
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• v.33 no.4
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• pp.273-282
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• 2000

In order to investigate the extent and degree of arsenic and heavy metal contamination and the bioavailability of toxic elements around the abandoned mine in Korea, an environmental geochemical survey was undertaken in the Daduk mine. After appropriate preparation, tailings, soil, stream sediment, crop plant and fingernail samples were analysed for As, Cd, Cu, Pb and Zn by ICP-AES and ICP-MS. Elevated levels of 8,782 mg/kg As, 8.3 mg/kg Cd, 489 mg/kg Cu, 3,638 mg/kg Pb and 919 mg/kg Zn were found in tailings from the Daduk mine. These significant concentrations can impact on soils and sediments around the tailing ponds. Mean concentrations of As, Cd, Pb, Cu and Zn in soils are significantly higher than those in world average soil, especially for As and Pb. Element concentrations in sediments decrease with distance from the tailing ponds due to a dilution effect by the mixing of uncontaminated sediments. Arsenic and Cd are elevated in rice grains and stalks, and Cu and Zn concentrations in chinese cabbage, sesame and bean leaves are higher than the upper limit values for normal plant. Arsenic concentration in fingernails of farmers are higher than the normal level with a maximum value of 1.5 mg/kg. The post-ingestion bioavailability of toxic heavy metals in some paddy and farmland soils has been also investigated using the SBET (simple bioavailability extract test) method. The method utilises synthetic leaching fluids closelyanalogous to those of the human stomach. The quantities of As, Cd, Cu, Pb and Zn extracted from paddy soils after 1 hour indicated 15.9, 65.4, 46.2, 39.4 and 29.4% bioavailability, respectively and for farmland soils, 12.4, 26.0, 31.2, 29.3 and 19.4% bioavailability, respectively. The results of the SBET indicate that regular ingestion of soils by the local population could pose a potential health threat due to long-term toxic element exposure.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.914-919
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• 2008

This present was carried out to evaluate the adaptability of stabilization method which was used industrial byproducts as the stabilization agency in the abandoned mine site. In order to investigate stabilization effect on As-contaminated soils treated by industrial by-products, batch tests and column tests were carried out with As-contaminated soils collected from farmland around the abandoned mine site. ZVI(zero valent iron) and SRS(steel refining slag) was shown a good treatment effect. After the column test, sequential extraction test and simple bioavailability extraction test(SBET) were carried out to analysis of the soil, and scanning electron micrograph(SEM) analysis was carried out to compare the morphology and structure of ZVI and SRS before and after reacting with arsenic in the soil. As a result, ZVI and SRS were shown 93%, 62% reduction of As concentration respectively by comparison with untreated soils. Therefore, if ZVI and SRS are used as treatment materials in As-contaminated soils, it is expected that the As leaching from soils is reduced effectively.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1463-1474
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• 2008

In order to investigate stabilization effect and sustainability on As-contaminated farmland soils which were affected the abandoned mine site and stabilized by zerovalent iron(ZVI) and industrial by-products, batch-scale and pilot-scale tests were carried out. In batch tests, ZVI and industrial by-products(blast furnace slag, steel refining slag and oyster shell powder) were used in treatment materials to reduce the As leaching. Industrial by-products were mixed with As-contaminated soils, in the ratio of 1%, 3%, 5% and 7% on the weight base of dried soil. The results of batch-scale tests was shown that the reduction of As concentration was observed in all samples and it was expected that ZVI and steel refining slag were more effective than other treatment materials to stabilize As compounds. In pilot-scale tests, columns were filled with untreated soils and treated soils mixed with ZVI and steel refining slag in the same mixing ratio of 3%. Distilled water was discharged into the columns with the velocity of 0.3 pore volume/day. During the test, pH, EC, Eh and As concentration were measured in the regular term(1pore volume). after six months, pilot-scale tests were retested to investigate sustainability of treatment materials. As a result, It was shown that the leachate from control column was continuously released during the test period and its concentration was greater than $100ug{\cdot}L^{-1}$ which was exceeded the national regulation of water discharged to river or stream ($50ug{\cdot}L^{-1}$). On the other hand, soil treated with ZVI and steel refining slag showed that the concentrations of leachate were lower than national regulation of water discharged to river or stream. Therefore it was expected that ZVI and steel refining slag could be applied to the farmland site as the alternative treatment materials.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.1
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• pp.36-40
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• 2014

Korea's agricultural land is constantly being reduced. The reasons for this are due to the change of agricultural profitability and the policy conditions. The reduction of agricultural land in 2010 showed a decline trend by 14.4 % of paddy fields and 1.2% of uplands compared to areas from 2000. These reductions were mainly due to switch rice paddy fields into upland or greenhouse facility cultivation because of low profitability of rice products compared to farm products. In addition, the permit system of agricultural areas was relaxed in switching paddy fields and this accelerated the reduction of agricultural land. For this reason, more than 1% of agricultural land area has been reduced every year for last five years. Moreover, indiscreet fill and cover materials such as construction wastes were used in agricultural lands and caused land contamination which threatened foundation as sustainable agricultural lands. For these reasons, it is a desperate situation to conserve good agricultural lands. However, the standards of transported soils, filling soils and cutting soils in the Agricultural Land Act are qualitative and have a problem of causing complaints. Therefore, the following criteria (proposals) are proposed in the Agricultural Land Act; (1) Use the proper soils for crops (criterion), (2) Soil components and amounts should be proper as transported soils (range), and (3) Prohibiting usage of improper earth rocks or recycled aggregates in case of filling soils (kinds). The presented criteria (proposals) suggest following; (1) Use physio-chemically proper soils for crops (criterion), (2) In case of transported soils, i, exclude potential acid sulphate soils, ii, gravel content sould be less than 15%, and iii, Heavy metals and other contaminants should be less than the soil contamination warning limit from the Ministry of Environments, (3) In case of filling soils, 13 kinds of recycled wastes specified in the Wastes Control Act should not be used as filling soils, (4) Practice soil conservation technology in case of sloping areas, and (5) Follow proper fertilizer application standards for maturing paddy fields and uplands when cutting soils.

• Magazine of the Korean Society of Agricultural Engineers
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• v.40 no.4
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• pp.77-84
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• 1998

Adsorption and leaching characteristics of the artificial soils produced from water and wastewater treatment sludges were examined. The batch adsorption test and TCLP leaching test were used, and constituents of interest were heavy metals and nutrients. As, Cr, Cu, Pb, and Cd were analyzed for metals, and nitrogen and phosphorus were analyzed for nutrients. All the artificial soils showed strong adsorption and low leaching for the heavy metals, which implies that the artificial soils may not be hazardous to the environment due to heavy metals and even they can be utilized effectively to remove metals in solution like mine and industrial wastewaters. This is quite promising result because in most case heavy metals are the most concern in the application of sludge product to the farmland. For the nutrients, generally, artificial soils showed high adsorption and low leaching except artificial soil from wastewater sludge produced by low temperature firing. The artificial soils produced from water treatment sludge were active in adsorbing nutrients and showed low leaching that they can be practically used to remove nutrients in advanced treatment process of the wastewater. The artificial soils produced from wastewater treatment sludge were less active in adsorbing nutrients and showed high teaching. However, they could be used usefully if applied properly to the plant growing because of their fertilizing effect. Based on the test results, overall, the artificial soils were thought to be not hazardous to the environment and they could be more useful if applied properly.