• 한국지하수토양환경학회지:지하수토양환경
• /
• 제18권7호
• /
• pp.63-72
• /
• 2013

This study estimated stabilization efficiency of As and heavy metal contaminated agricultural soil in abandoned mine through pot experiment. Also contaminants uptake of plant (lettuce) was compared as function of amendment (limestone, steelmaking slag and the mixture of these) addition. In soil solution analysis, concentration of contaminants in soil solutions which added limestone or steelmaking slag were lower than that of the mixture. Especially in As analysis, concentration with 5% (wt) addition of steelmaking slag showed the lowest value among those with other amendments. This seems that As stabilization happens through Fe adsorption during precipitation of Fe by pH increasing. Leachability of As in stabilized soil by TCLP was represented similar result with soil solution analysis. However leachability of heavy metals in stabilized soil was similar with that of non-stabilized soil due to dissolution of alkali precipitant by weak acid. Contaminants uptake rate by plant was also lower when limestone or steelmaking slag was used. However this study revealed that concentration of contaminants in soil solution didn't affect to the uptake rate of plant directly. Because lower $R^2$ (coefficient of determination) was represented in linear regression analysis between soil solution and plant.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제18권7호
• /
• pp.1-11
• /
• 2013

The actively soil pollution by the toxic heavy-metals like the arsenic, cadmium, lead due to the industrialization and economic activity. The uses the electrokinetic remediation of contaminated soil has many researches against the fine soil having a small size in the on going. However, it is the actual condition which the research result that is not effective due to the low surface charge of the particle and high permeability shows in the electrokinetic remediation in comparison with the fine soil in the case of the sandy soil in which the particle size is large. In this research, the electrokinetic remediation and ultrasonic wave fetch strategy is compound applied against the sandy soil polluted by the arsenic, cadmium, and lead removal efficiency of the sandy soil through the comparison with the existing electrokinetic remediation tries to be evaluated. First of all, desorption of contaminants in soil by ultrasonic extraction in the Pre-Test conducted to see desorption effective 5~15%. After that, By conducted Batch-Test results frequency output century 200 Khz, reaction time 30 min, contaminated soil used in experiment was 500 g. Removal efficiency of arsenic, cadmium, lead are 25.55%, 8.01%, 34.90%. But, As, Cd, Pb remediation efficiency less than 1% in EK1(control group).

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제25권2호
• /
• pp.9-15
• /
• 2020

This study was conducted to investigate the in situ formation of amorphous Fe oxides as a stabilization technology in As-contaminated soil. After addition of ferric nitrate and the neutralizing agent, most of extractable fractions of As in soil (i.e., SO₄^2- and PO₄^3--extractable As) was converted into As bound to amorphous Fe oxides. In addition, results of solubility bioavailability research consortium (SBRC) test indicated that a significant amount of As in untreated soil changed to a non-bioaccessible form after stabilization. The reason was attributed to the newly formed amorphous Fe oxides in the stabilized soil, which was confirmed by linear combination of fitting (LCF) using X-ray absorption spectroscopy (XAS) analysis. Interestingly, after five months of aging of the stabilized soil, ferrihydrite and schwertmannite newly formed in the soil were transformed to crystalline Fe oxides such as goethite, and further decrease in SBRC extractable fraction of As was observed. The results suggest that co-precipitated As with amorphous Fe oxides can be further immobilized with time, due to the crystallization of amorphous Fe oxides.

• 한국환경농학회지
• /
• 제28권4호
• /
• pp.378-385
• /
• 2009

Arsenic (As) is known to be very toxic and carcinogenic to human beings. Arsenic contaminated soil was collected from a timber mill site at Busan Metropolitan City, Korea, where chromated copper arsenate (CCA) had been used to protect wood from rotting caused by insects and microbial agents. The soil was stabilized using both natural oyster shells (NOS) and calcinated oyster shells (POS). The calcination of natural oyster shells was accomplished at a high temperature in order to activate quicklime from calcite. Two different oyster shell particle sizes (-#10 mesh and -#20 mesh) and curing periods of up to 28 days were investigated. The stabilization effectiveness was evaluated based on the Korean Standard Test (KST) method (1N HCl extraction). The stabilization results showed that the POS treatment was more effective than the NOS treatment at immobilizing the As in the contaminated soils. A significant As reduction (96%) was attained upon a POS treatment at 20 wt% and passed the Korean warning standard of 20 mg/kg ('Na' area). However, an As reduction of only 47% (169 mg/kg) was achieved upon a NOS treatment at 20 wt%. The -#20 mesh oyster shells seem to perform better than the -#10 materials. The scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDX) results showed that As immobilization was strongly associated with Ca and O in the presence of Al and Si.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제21권6호
• /
• pp.87-100
• /
• 2016

Biochar, which has high alkalinity, has widely studied for amendment of soil that contaminated with heavy metals. The aim of this study is assessment of amendment for arsenic and heavy metals contaminated acidic agricultural soil using biochar that derived from buffalo weed (A. trifida L. var. trifida). Pot experiments were carried out including analysis of soil solution, contaminants fractionation, soil chemical properties and plant (lettuce) uptake rate. Arsenic and heavy metals concentrations in soil solution showed relatively low in biochar added experiments when compared to the control. In the heavy metals fractionation in soil showed decrease of exchangeable fraction and increase of carbonates fraction; however, arsenic fractionations showed constant. Soil chemical properties indicated that biochar could induce recovery of soil quality for plant growth in terms of soil alkalinity. However, phosphate concentration in biochar added soil decreased due to Ca-P precipitation by exchangeable calcium from biochar. Arsenic and heavy metals uptake rate of plant in the amended experiment decreased to 50% when compared to the control. Therefore biochar derived from buffalo weed can be used as amendment material for agricultural soil contaminated with arsenic and heavy metals. Precipitation of As-Ca and metal-carbonates are major mechanisms for soil amendment using char.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
• /
• pp.229-241
• /
• 2008

In order to investigate stabilization effect on As-contaminated soils treated by zero-valent iron(ZVI) and industrial by-products, batch tests and column tests were carried out with As-contaminated soils collected from farmland around the abandoned mine site. In batch tests, ZVI and industrial by-products(blast furnace slag, steel refining slag and oyster shell powder) were used as treatment materials to reduce As. 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. After incubation, all samples showed the reduction of As concentration and it was expected that ZVI and steel refining slag were effective treatment materials to remove As among treatment materials used in batch test. In column tests, columns were made by acrylic with the dimension of diameter=10cm, height=100cm, thickness=1cm and these columns were filled with untreated soils and treated soils mixed with ZVI and steel refining slag(mixing ratio=3%). Distilled water was discharged into the columns with the velocity of 1 pore-volume/day. During test, pH, EC, Eh and As concentration were measured in the regular term(1 pore-volume). As a result, ZVI and steel refining slag were shown 93%, 62% reduction of As concentration respectively by comparison with untreated soils. Therefore, if ZVI and steel refining slag are used as treatment materials in As-contaminated soils, it is expected that the As concentration in soils is reduced effectively.

• 한국물환경학회지
• /
• 제33권3호
• /
• pp.334-340
• /
• 2017

A pilot-scale electrodialysis system was designed and constructed to treat groundwater polluted with arsenic and manganese. Synthetic groundwater, in which some amount of arsenic and manganese was added to make 500 mg/L of Mn and $50{\mu}g/L$ of As, was used as a feed for the ED system. The limiting current density, linear water velocity, applied voltage, and membrane surface area were investigated to obtain efficient and economic operation of the ED system. The linear water velocity was increased 0.74 cm/s to 11 cm/s based on evaluation of limiting current density. The water quality of diluate for 85 minutes of operation was satisfied with water quality criteria for drinking water using the ED system with 14 pairs of ion exchange membranes. The increased membrane pairs to 21 and 42 pairs were very effective to reduce conductivities of the diluate. The operation cost of the ED system was assessed using specific energy consumption, which was $1.065{\sim}1.2kWh/m^3$. Considering low salt concentrations of the groundwater, improvement of the ED system are required to increase current utilization and to apply low voltage while the ED system was applicable to produce drinking water.

• 한국식품위생안전성학회지
• /
• 제17권4호
• /
• pp.178-182
• /
• 2002

전국 폐광지역(48곳) 평야지역(8곳) 농산물(280건), 토양(280건), 농경수(48건)를 채취하여 수은 함량은 Mercury analyzer로, 납, 카드뮴, 비소 등 중금속은 습식분해후 ICP, AAS등으로 분석하였다. 본 연구결과, 평야지역에 비해 폐광산지역의 토양에 있어 크롬을 제외한 수은, 납 등 중금속 함량이 더 높았으며 농경수에 있어서는 수은을 제외한 다른 중금속함량이 더 높았다. 폐광산지역의 농산물중 납, 카드뮴 등 중금속 함량은 평야지역에 비해 대체로 높은 편이었으나 구리 함량은 평야지역의 농산물이 다소 높았다. 토양과 농산물중 납 등 중금속함량간의 유의적인 상관관계는 관찰되지 않았다(p>0.05). 앞으로도 식품의 안전성 확보 및 국민건강증진차원에서 폐광산지역의 토양, 농산물중 중금속 함량에 대한 모니터링 사업이 지속적으로 수행되어야 할 것으로 사료된다.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2008년도 추계 학술발표회
• /
• pp.1463-1474
• /
• 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.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제22권6호
• /
• 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.