NATIONAL ARTICLES

Title
균질한 매질 내 Calcium polysulfide 주입에 따른 고농도 중금속 오염 지하수 정화 타당성 검토

Abstract

In this study, column tests using relatively uniform Jumunjin sand media were conducted to evaluate the feasibility of calcium polysulfide (CaS_x, CPS) in removing high concentration of Zn²⁺ in groundwater. The injected CPS solution reacted rapidly with Zn²⁺ in artificial groundwater and effectively reduced Zn²⁺ by more than 99% through metal sulfide precipitation. Since the density (d = 1.27 g/cm³ ) of CPS solution was greater than that of water, CPS solution settled down rapidly while capturing Zn²⁺ and formed stable CPS layer similar to dense nonaqueous phase liquid. Mass balance analysis on Zn²⁺ in CPS solution suggested that CPS solution effectively reacted with Zn²⁺ to form metal sulfide precipitates except for high groundwater seepage velocity of 400 cm/d. With greater groundwater seepage velocity, injected CPS did not completely dissolve at the CPS-water interface, but a partially-misible CPS layer continuously moved and reacted with Zn²⁺+ in the direction of groundwater flow. Since hydraulic conductivity (K_h) decreased slightly due to the generated metal precipitates in the inter-pores of media, injection of CPS solution should be optimized to prevent clogging. As evidenced by both XRF and SEM/EDS results, ZnS precipitates were clearly observed through the reaction between the CPS solution and Zn²⁺. Further study is warranted to evaluate the feasibility of CPS to remove high-concentration heavy metalcontaminated groundwater in complex and heterogeneous media.

Keywords

DOI: https://doi.org/10.7857/JSGE.2023.28.1.001

Title
칼슘 및 칼륨 용액을 이용한 원자력발전소 주변 스트론튬과 세슘 오염토양 세척기술 연구

Abstract

Calcium (Ca) and potassium (K) were introduced to remove Sr and Cs in soil, respectively. Four factor and three level Box-Bhenken design was employed to determine the optimal washing condition of Ca- and K-based solutions, and the ranges tested were 0.1 to 1 M of Ca or K, L/S ratio of 5 to 20, washing time of 0.5 to 2 h, and pH of 2 to 7. The optimal washing condition determined was 1 M of Ca or K, L/S ratio of 20, washing time of 1 h, and pH of 2, and Ca-based and K-based solutions showed 68 and 81% removal efficiency for Sr and Cs, respectively in soil. For comparison, widely used conventional washing agents such as 0.075 M EDTA, 0.01 M citric acid, 0.01 M oxalic acid, and 0.05 M phosphoric acid were tested, and they showed 25 to 30% of Sr and Cs removal efficiency. Tessier sequential extraction was employed to identify the changes in chemical forms of Sr and Cs during the washing. In contrast to the conventional washing agents, Ca-based and K-based solutions were able to release relatively strongly bound forms of Sr and Cs such as Fe/Mn-oxide and organic matter bound forms, suggesting the involvement of direct substitution mechanism, probably due to the physicochemical similarities between Sr-Ca and Cs-K.

Keywords

DOI: https://doi.org/10.7857/JSGE.2022.27.2.076

Title
유류오염부지 시범적용을 통한 실외공기 오염물질흡입 노출경로에 대한 부지특이적 노출량 산정 방안에 대한 고찰

Abstract

Exposure assessment methodology for outdoor air inhalation pathways (i.e., inhalation of volatile compounds and fugitivedust in outdoor air) was investigated. Default values of several parameters currently used in Korea (e.g., Q/C; inversevalue of concentration per unit flux, and frs; soil fraction in PM10) may not be suitable and lack site-specificity, as theyhave been adopted from the risk assessment guidance of the United States or the Netherlands. Such limitation can beaddressed to a certain degree by incorporating the volatilization factor (VF) and the particulate emission factor (PEF) withBox model. This approach was applied to an exposure assessment of a site contaminated with petroleum hydrocarbons inKorea. The result indicated that the suggested methodology led to more accurate site-specific exposure assessment foroutdoor inhalation pathways. Further work to establish methodology to determine site-specific Q/C values in Korea needsto be done to secure the reliability of the exposure assessment for outdoor air inhalation pathways.

Keywords

DOI: 10.7857/JSGE.2020.25.3.065

Title
위해성기반 오염부지관리를 위한 의사결정체계 및 이를 위한 위해저감기술의 활용

Abstract

오염부지 관리 기조가 매체 중심에서 수용체 중심으로 변화하면서 우리나라에 위해성평가 제도가 도입되었으나, 이를 오염현장에 충분히 활용하기 위한 체계와 관련 기술들은 아직 제대로 확립되어 있지 않다. 특히, 여러 가지 이유로 정화곤란부지로 분류가 되는 오염부지의 정화 및 관리와 그러한 부지에 적용될 수 있는 위해저감기술들에 대한 기술적, 사회적 논의와 합의도 부족한 실정이다. 본 연구에서는 그동안 오염토양의 정화에만 초점이 맞추어진 우리나라의 토양환경정책이 오염부지의 관점에서 그와 연결된 수용체를 보호하는 방향으로 나아가기 위해 필요한 위해성기반 오염 부지관리 의사결정체계를 제안하고, 그러한 관리체계가 현장에서 적절히 적용되도록 하기 위해 필요한 위해저감기술들을 조사, 분류하여 위해저감 방식에 따른 위해저감기술의 활용성 및 적용성을 평가하는 방안을 제안하였다.

Keywords

위해성평가, 오염부지 위해관리체계, 위해저감기술

DOI: https://doi.org/10.7857/JSGE.2020.25.3.032

Title
비결정질철산화물 원위치 형성을 통한 비소오염토양 안정화 및 X선 분광분석법의 활용에 대한 연구

Abstract

X-ray absorption fine structure (XAFS) analysis using X-ray absorption spectroscopy is being applied as a state-of-the-art method in a wide range of disciplines. This review article summarizes the overall procedure of XAFS analysis from the preparation of soil samples to the analysis of data in X-ray absorption near edge structure (XANES) region and extended X-ray absorption fine structure (EXAFS) region. The previous studies on application of XANES and EXAFS techniques in environmental soil science field are discussed and classified them according to metal(loid)s (As, Cd, Cu, Ni, Pb, and Zn). A significant number of previous studies of XAFS application in the environmental soil science field have focused on the identification of Pb chemical species in soil. Moreover, XANES and EXAFS techniques have been widely used to investigate the contamination source via identification of metal species. Similarly, these techniques were applied to identify the mechanisms of metal stabilization in soil after application of various amendments, phytoremediation, etc.

Keywords

Co-precipitation, Arsenic, Amorphous Fe oxides, Crystallization, X-ray absorption spectroscopy (XAS)

DOI: https://doi.org/10.7857/JSGE.2020.25.2.009

Title
국내 대수층 특성을 반영한 포화대 내 유류오염물질 거동 개념 모델에서 수리동역학적 및 반응 입력인자 민감도 평가

Abstract

Sensitivity analysis of hydrodynamic and reaction parameters in conceptual model reflecting aquifer characteristics of
Korea was performed to evaluate the uncertainty in the predicted concentrations. Among the hydrodynamic input
parameters, both hydraulic conductivity (Kx) and hydraulic gradient (I) affected transport behaviors of contaminants, and
resulted in same convergence concentrations with continuous injections of contaminant. However, longitudinal dispervisity
(αL) affected both transport behaviors and the convergence concentrations of contaminants. Compared to the
hydrodynamic parameters, growth kinetic and degradation parameters (μm & Kc) more significantly affected both transport
behaviors and the convergence concentrations of contaminants, indicating those parameters had higher sensitivity indices
causing the uncertainties of model predictions. Considering that the sensitivity indices of both hydrodynamic and reaction
parameters were a function of transport distance of groundwater, the parameters with higher sensitivity indices, a priori,
need to be investigated using conceptual model reflecting site-specific aquifer characteristics before field investigation.
After determining the parameters with higher sensitivity indices, the detail field investigations for the selected
hydrodynamic and reaction parameters were warranted to reduce the uncertainties of model predictions.

Keywords

Conceptual model, Groundwater, Hydrodynamic parameter, Reaction parameter, Sensitivity analysis, Uncertainty

DOI: https://doi.org/10.7857/JSGE.2020.25.1.037

Title
비소오염토양에서 반복적인 Redox 환경 변화가 토양 미생물 군집과 비소 및 철의 순환에 미치는 영향

Abstract

In a redox transition zone, geochemical reactions are facilitated by active bacteria that mediate reactions involving
electrons, and arsenic (As) and iron (Fe) cycles are the major electron transfer reactions occurring at such a site. In this
study, the effect of repetitive redox changes on soil bacterial community in As-contaminated soil was investigated. The
results revealed that bacterial community changed actively in response to redox changes, and bacterial diversity gradually
decreased as the cycle repeated. Proportion of strict aerobes and anaerobes decreased, while microaerophilic species such
as Azospirillum oryzae group became the predominant species, accounting for 72.7% of the total counts after four weeks
of incubation. Bacterial species capable of reducing Fe or As (e.g., Clostridium, Desulfitobacterium) belonging to diverse
phylogenetic groups were detected. Indices representing richness (i.e., Chao 1) and phylogenetic diversity decreased from
1,868 and 1,926 to 848 and 1,121, respectively. Principle component analysis suggests that repetitive redox fluctuation,
rather than oxic or anoxic status itself, is an important factor in determining the change of soil bacterial community, which
in turn affects the cycling of As and Fe in redox transition zones.

Keywords

Redox transition zone, Bacterial community, Phylogenetic diversity, As contaminated soil

DOI: https://doi.org/10.7857/JSGE.2020.25.1.025

Title
라돈가스의 문제점과 사례분석을 통한 해결방안

Abstract

본 연구에서는 라돈가스의 환경적 문제점을 구체적으로 파악하였다. 각 나라별 라돈가스 환경문제 사례 분석을 통하
여 국가별 라돈 가스 농도와 위험도를 조사하였다. 환경적 문제가 되는 라돈가스 유입의 방지법을 조사 및 연구하여
소개한다.

Keywords

라돈가스, 사례분석, 공학적 차단기술

DOI: https://doi.org/10.7857/JSGE.2020.25.1.001

Title
석유계총탄화수소의 위해성평가 시 적정 분획 시료수 결정에 대한 고찰

Abstract

In this study, a reliable number of soil samples for TPH fractionation was investigated in order to perform risk assessment.
TPH was fractionated into volatile petroleum hydrocarbons (VPH) with three subgroups and extractable petroleum
hydrocarbons (EPH) with four subgroups. At the study site, concentrations of each fraction were determined at 18
sampling points, and the 95% upper confidence limit (UCL) value was used as an exposure concentration of each fraction.
And then, 5 sampling points were randomly selected out of the 18 points, and an exposure concentration was calculated.
This process was repeated 30 times, and the results were compared statistically. Exposure concentrations of EPH obtained
from 18 points were 99.9, 339.1, 27.3, and 85.9 mg/kg for aliphatic C9-C18, C19-C36, C37-C40, and aromatic C11-C22,
respectively. The corresponding exposure concentrations obtained from 5 points were 139.8, 462.8, 35.1 and 119.4 mg/kg,
which were significantly higher than those from 18 points results (p <0.05). Our results suggest that limited number of
samples for TPH fractionation may bias estimation of exposure concentration of TPH fractions. Also, it is recommended
that more than 30 samples need to be analyzed for TPH fractionation in performing risk assessment.

Keywords

Risk assessment, Exposure concentration, TPH fractionation, TPH EPH, TPH VPH

DOI: https://doi.org/10.7857/JSGE.2019.24.5.011

Title
오염부지 위해성평가 시 오염물질 노출이동경로 평가를 위한 수치모델 적용에 관한 연구

Abstract

The purpose of this study is to suggest conceptual models based on finite numerical method that can be used to assess contaminant transport through subsurface and estimate exposed concentration at contaminated site. This study tested various assumptions of the numerical models for contaminant transport in unsaturated and saturated zones to simulate the pathways to the human exposal point. For this purpose, models for seven possible scenarios of contaminant transport were simulated using the numerical code MODFLOW and MT3D. The simulation results that showed different peak concentrations and travel times were compared. In conclusion, the potential utility of the numerical models in the site specific risk analysis suggested as well as future research ramifications.

Keywords

Risk assessment, Exposed concentration, Numerical model, Groundwater, Contaminated site

DOI: https://doi.org/10.7857/JSGE.2019.24.3.013

Title
제일인산칼륨과 몬트모릴로나이트 점토를 이용한 사격장 토양 내 2,4,6-trinitrotoluene의 흡착증진 및 탈착감소에 의한 이동성 저감 연구

Abstract

Mobility reduction of 2,4,6-trinitrotoluene (TNT) was tested by amending monopotassium phosphate (MKP) andmontmorillonite to a firing range soil contaminated with TNT. While addition of MKP enhanced sorption of TNT on soilmatrix, and combined use of MKP with montmorillonite significantly decreased desorption of TNT as well as remarkablyincreased the TNT sorption. Montmorillonite amendment by 5% of soil mass resulted in TNT desorption of 0.12 mg/kgfrom soil loaded with 9.93 mg/kg-TNT. The decrease of TNT desorption was proportional to the amount ofmontmorillonite amended. At 10 and 15% amendment, only 0.79 and 1.23 mg/kg-TNT was desorbed from 29.33 and48.80 mg/kg-TNT. In addition, the leaching of TNT with synthetic precipitation leaching procedure (SPLP) andhydroxypropyl-β-cyclodextrin (HPCD) decreased, indicating that TNT in MKP/montmorillonite-treated soil became morestable and less leachable. The results demonstrate that addition of MKP and montmorillonite to TNT-contaminated soilreduces the mobility of TNT from soil not only by increasing TNT sorption, but also decreasing TNT desorption. It wasfound that MKP and montmorillonite amendments by 5 and 10% of soil mass, respectively, were optimal for reducing themobility of soil TNT.

Keywords

2,4,6-Trinitrotoluene,  Monopotassium phosphate,  Montmorillonite,  Desorption

DOI: http://dx.doi.org/10.7857/JSGE.2018.23.6.046

Title
준설토의 육상 유효활용을 위한 환경위해성평가 및 특성분석 기반 의사결정모델

Abstract

준설토는 다양한 용도로 유효활용 될 수 있는 가치 있는 자원임에도 불구하고 해마다 많은 양이 단순 투기 및 매립으로 처리되고 있다. 이러한 요인 중 하나로 준설토 유효활용과 관련한 일관된 의사결정 체계의 부족을 꼽을 수 있다. 본 연구에서는 이러한 문제를 극복하기 위해서 준설토 유효활용 가능여부, 활용용도, 용도별 적합성 등을 결정하는 합리적인 의사결정 모델을 제시하고자 하였다. 본 연구의 준설토 유효활용 대상은 육상 재활용으로 한정하고, 유효활용의 용도를 크게 습지조성, 서식지 조성, 토양개량제, 농업용 토양 등 생태자원과 성토재, 복토재, 간척지 조성, 매립지 덮개 등 공학재료로 구분하였다. 각 용도에 따른 의사결정에 필요한 결정인자로 오염물질 전함량, 단기 및 장기용출특성, 이화학적 특성, 공학기능, 생태독성영향, 오염물질 확산특성 등을 제시하였다. 각 결정인자에 대한 분석을 통하여 평가단계를 가장 합리적인 순서로 배치함으로써 주변 환경 및 생태계 영향을 최소화하고 준설토의 가치를 최대한 활용할 수 있는 의사결정모델을 제시하였다.

Keywords

의사결정모델, 유효활용, 준설토, 환경위해성평가, 특성분석

Title
건설폐기물을 성토재로 사용한 산업단지에서의 중금속 오염 원인 규명

Abstract

This paper is aimed at source tracking of soil heavy metal contamination at a site established by reusing construction wastes. The soil heavy metal concentration at the study site peaked at a depth range of 5-10 m. Column studies were conducted to investigate the possibility of the contamination scenario of infiltration of stormwater carrying heavy metals of ground origin followed by selective heavy metal accumulation at the 5-10 m depth range. Almost all amount of lead, zinc, cadmium, and nickel introduced to the columns each packed with 0-5 m or 5-10 m field soil were accumulated in the column. The very poor heavy metal mobility in spite of the weak association of the heavy metals with the soil (characterized by a sequential extraction procedure) can be attributed to the high pH (10-11) of the construction wastes.
From the results, the heavy metal contamination of the subsurface soil by an external heavy metal source was determined to be very unlikely at the study site. The column study applied in the current study is expected to be a useful methodology to present direct evidence of the contaminant source tracking at soil contamination sites.

Keywords

Construction waste, Heavy metal, Leaching, Source identification, Column study

DOI

http://dx.doi.org/10.7857/JSGE.2018.23.1.054

Title
토양시료의 분쇄가 왕수분해법을 이용한 비소와 납의 전함량 분석 결과에 미치는 영향

Abstract

The effect of soil grinding on total As and Pb concentrations determined by aqua regia method was examined. Among six field-collected, air-dried soil samples tested, soils A, B, C, and E were directly sieved through a 150−μm”>150−μm150−μm sieve without grinding and showed 2.18 to 3.03 times higher total As concentrations and 2.62 to 3.45 times higher total Pb concentrations than those of the soil samples prepared to allow all soil particles to pass through the 150−μm”>150−μm150−μm sieve by grinding. The reason can be ascribed to the fact that those soils contain fine particles (i.e., 150μm”>150μm150μm in diameter) only 4.6 to 6.8% of the total soil weights. On the other hand, for D and F soils, fine particles smaller than 150μm”>150μm150μmaccounted for 57 and 46%, respectively, so that the effect of grinding on As and Pb concentrations were relatively low (As: 1.15 and 1.23 times, Pb: 1.36 and 1.49 times, respectively). The result demonstrates that grinding prior to150−μm”>150−μm150−μm sieving is necessary to ensure the homogeneity of soil samples and hence to obtain more accurate heavy metal concentrations in soils. This is especially true for soil samples with less fine soil particles and/or microaggregates (i.e., below 150μm”>150μm).

Keywords

Grinding, Sieving, Aggregate, Heavy metal, Aqua regia digestion

DOI

http://dx.doi.org/10.7857/JSGE.2018.23.1.025

Title
강산 및 강염기 토양 유출에 따른 토양의 생태기능 관련 토양특성 변화

Abstract
본 연구에서는 강산 및 강염기 유출사고가 발생하였을 때 육상생물의 생육에 영향을 미칠 수 있는 토양특성의 변화를 살펴보았다. 강산과 강염기 화학물질로 HCl과 NaOH을 선정하였으며 이들 물질을 토양과 반응시킨 후 토양의 토성, 비표면적, 유기물 함량, pH, 양이온교환능력 및 치환성양이온 함량 변화를 측정하였다. 토양과 반응한 HCl 및 NaOH 농도가 각각 10 M과 1 M인 경우 (즉, 토양 1 g 당 50 mmol의 HCl이나 5 mmol의 NaOH가 유입된 경우) 유의한 수준의 토양 특성 변화가 관찰되었다. 10 M HCl 및 1 M NaOH 용액과 반응한 토양의 토성은 sandy loam에서 loamy sand로 변하였으며, 비표면적은 5.84 ㎡/g에서 각각 4.85 및 1.92 ㎡/g으로 감소하였다. 토양 유기물 함량은 3.23%에서 0.96 및 0.44%로 크게 감소하였으며, 반응 전 pH 5.05로 약산성인 토양의 pH는 각각 2.35 및 10.65로 변하였다. 토양 내 양이온교환능력은 10.27 cmol/kg에서 4.52 및 5.60 cmol/kg으로 크게 감소하였으며 Na+을 제외한 알칼리성 양이온 (K⁺, Mg²⁺, Ca²⁺)의 함량이 감소하였다. HCl과 반응한 경우 Na⁺ 함량은 감소, Al³⁺ 함량은 증가하였으나 반대로 NaOH와 반응한 경우 Na⁺ 함량은 증가, Al³⁺ 함량은 감소하였다. 높은 농도의 Al³⁺과 Na⁺은 각각 토양생물에게 직접적인 독성을 발현하거나 토양의 투수성을 감소시키고 중탄산염의 농도를 증가시켜 독성을 발현할 수 있다. 본 연구는 강산 및 강염기 유출사고로 인하여 변화한 토양특성이 토양의 생태기능에 영향을 줄 수 있음을 보여준다.

Keywords
산･염기 화학반응, 화학사고, 토양특성, 육상생물,  CuOH+,  CuCO3(aq)

DOI

http://dx.doi.org/10.17820/eri.2017.4.4.193

Title
Effect of Cu Species Distribution in Soil Pore Water on Prediction of Acute Cu Toxicity to Hordeum vulgare using Terrestrial Biotic Ligand Model

Abstract
In this study, the predictive toxicity of barley Hordeum vulgare was estimated using a modified terrestrial biotic ligand model (TBLM) to account for the toxic effects of CuOH+ and CuCO3(aq) generated at pH 7 or higher, and this was compared to that from the original TBLM. At pH values higher than 7, the difference in EA50{Cu2+} (half maximal effective acitivty of Cu2+) between the two models increased with increasing pH. As Mg concentration increased from 8.24 to 148 mg/L in the pH range of 5.5 to 8.5, the difference in EA50{Cu2+} increased, and it reached its maximum at pH 8. The difference in EC50[Cu]T (half maximal effective concentration of Cu) between the two models increased as dissolved organic carbon (DOC) concentration increased when pH was above 7. Thus, for soils with alkaline pH, the toxic effect of CuOH+ and CuCO3(aq) are greater at higher salt and DOC concentrations. The acceptable Cu concentration in
soil porewater can be estimated by the modified TBLM through deterministic method at pH levels higher than 7, while combination of TBLM and species sensitivity distribution through the probabilistic method could be utilized at pH levels lower than 7.

Keywords
Copper, CuOH+, CuCO3(aq), Terrestrial biotic ligand model, Acceptable Cu concentration

Title
Application of Galvanic Oxidation and Pyrite Dissolution for Sustainable In-Situ Mine Tailings Treatment

Abstract
Mine tailings generated during mining activity often contain high concentrations of heavy metals, with pyrite-containing mine tailings in particular being a major cause of environmental problems in mining areas. Chemical cell technology, or fuel cell technology, can be applied to leach heavy metals in pyrite-containing mine tailings. As pyrite dissolves through spontaneous oxidation (i.e. galvanic oxidation) in the anode compartment of the cell, Fe3+, sulfuric acid are generated. A decrease in pH due to the generation of sulfuric acid allows heavy metals to be leached from pyrite-containing mine tailings. In this study, pyrite was dissolved for 4 weeks at 23°C in an acidic solution (pH 2) and in a galvanic reactor, which induces galvanic oxidation, and total Fe leached from pyrite and pH were compared in order to investigate if galvanic oxidation can facilitate pyrite oxidation. The change in the pyrite surface was analyzed using a scanning electron microscope (SEM). Comparing the total Fe leached from the pyrite, there were 2.9 times more dissolution of pyrite in the galvanic reactor than in the acidic solution, and thus pH was lower in the galvanic reactor than in the acidic solution. Through SEM analysis of the pyrite that reacted in the galvanic reactor, linear-shaped cracks were observed on the surface of the pyrite. The study results show that pyrite dissolution was facilitated through the galvanic oxidation in the galvanic reactor, and also implied that the galvanic oxidation can be one remediation option for pyrite-containing mine tailings.

Keywords
Galvanic oxidation, Iron, Mine tailings, Pyrite dissolution

Title
Applicability of Stabilization with Iron Oxides for Arsenic-Contaminated Soil at the Forest Area near the Former Janghang Smelter Site

Abstract
This study evaluated the applicability of stabilization of arsenic (As)-contaminated soil with iron (Fe) oxides at the former Janghang smelter site. Three Fe oxides (magnetite, goethite, and hematite) were tested as stabilizing agents to one soil sample collected from the study site. Amendment of 5% of magnetite, goethite, or hematite for one week showed the 64, 58, and 36% of reduction of the SBRC (Solubility/Bioavailability Research Consortium)-extractable (bioaccessible) As, respectively. Duration of stabilization more than one week did not show an additional reduction in SBRC-extractable As. Amendment of 5% of magnetite, which showed the highest As stabilization efficiency, was applied to 24 soil samples collected from the same site for one week, and 72% of reduction in the bioaccessible As was observed. The potential carcinogenic human health risk at the study site caused by As was , which could be reduced to by the amendment of 5% magnetite for one week.

Keywords
Former Janghang smelter, Arsenic, Stabilization, Iron oxides, Magnetite