• Journal of Microbiology and Biotechnology
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• 제24권4호
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• pp.534-544
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• 2014

The effects of microbial iron reduction and oxidation on the immobilization and mobilization of copper were investigated in a high concentration of sulfate with synthesized Fe(III) minerals and red earth soils rich in amorphous Fe (hydr)oxides. Batch microcosm experiments showed that red earth soil inoculated with subsurface sediments had a faster Fe(III) bioreduction rate than pure amorphous Fe(III) minerals and resulted in quicker immobilization of Cu in the aqueous fraction. Coinciding with the decrease of aqueous Cu, $SO_4{^{2-}}$ in the inoculated red earth soil decreased acutely after incubation. The shift in the microbial community composite in the inoculated soil was analyzed through denaturing gradient gel electrophoresis. Results revealed the potential cooperative effect of microbial Fe(III) reduction and sulfate reduction on copper immobilization. After exposure to air for 144 h, more than 50% of the immobilized Cu was remobilized from the anaerobic matrices; aqueous sulfate increased significantly. Sequential extraction analysis demonstrated that the organic matter/sulfide-bound Cu increased by 52% after anaerobic incubation relative to the abiotic treatment but decreased by 32% after oxidation, indicating the generation and oxidation of Cu-sulfide coprecipitates in the inoculated red earth soil. These findings suggest that the immobilization of copper could be enhanced by mediating microbial Fe(III) reduction with sulfate reduction under anaerobic conditions. The findings have an important implication for bioremediation in Cu-contaminated and Fe-rich soils, especially in acid-mine-drainage-affected sites.

• 한국지하수토양환경학회지:지하수토양환경
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• 제25권2_spc호
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• pp.86-100
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• 2020

Analyzing and monitoring environmental contaminants based on geophysical exploration techniques have become important and it is now widely applied to delineate spatial distribution geophysical characteristics in wide area. Among the techniques, induced polarization (IP) method, which measures polarization effects on electrical potential distribution, has drawn much attention as an effective tool for environmental monitoring since IP is sensitive to changes in biochemical reactions. However, various reactions stemming from the presence of multiple contaminants have greatly enhanced heterogeneity of polluted sites to result in highly variable electrical characteristics of the site. Those contaminants influence chemical and physical state of soil and groundwater to alter electrical double layer, which in turn influences polarization of the media. Since biochemical reactions between microbes and contaminants result in various IP effects, IP laboratory experiments were conducted to investigate IP responses of the contaminated soil samples under various conditions. Field IP surveys can delineate the spatial distribution of contamination, while providing additional information about electrical properties of a target medium, together with DC resistivity. Reviewing IP effects of contaminants as well as IP surveys can serve as a good starting point for the application of IP survey in site assessment for environmental remediation.

• 자원환경지질
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• 제40권5호
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• pp.551-561
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• 2007

본 연구는 토양오염의 공간적 확산 및 거동을 이해하기 위한 측정방법을 고찰하고, 토양공극수 채취와 해석에 관한 사례연구이다. 이를 위해서 석유계 탄화수소로 오염된 대표적인 국내 유류오염부지 토양내 PAH류(Polycyclic aromatic hydrocarbons)의 오염 확산과 거동을 정량하기 위한 심도별 토양공극수의 추출장치를 구성하고, 불포화층과 포화층의 토양수를 분석하여 오염물질의 거동을 해석하였다. 토양공극수 추출장치는 공극수 추출용 압력펌프와 토양공극수 추출부로 구성되고, 토양수분장력과 추출압력을 동시에 측정하며 심도별로 토양공극수를 채취하도록 구성하였다. PAH류 오염물질은 추출압력과 시간에 따른 주변 토양공극수의 유입에 의한 희석에 의해서 농도가 낮아졌다. 특히, 추출 심도에 따라 토양의 산화환원전위의 영향에 의해 불포화층의 산화환경에서 포화층의 환원환경보다 자연저감정도가 높았다. 따라서 토양수분장력의 세기에 따라 강한 토양수분장력의 모세관수와 약한 장력의 중력수에 해당하는 토양공극수를 추출함으로써 토양공극수의 평형과 비평형정도를 해석할 수 있다.

• 대한환경공학회지
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• 제35권7호
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• pp.503-508
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• 2013

본 연구의 목적은 가축사체 매몰지 토양의 침출수 오염에 따른 병원성 미생물에 의한 잠재적 위해성을 평가하기 위하여 미생물 군집을 조사하는 것이다. 경기도 지역에 위치한 가축사체 매몰지 세 군데(A, B, C) 토양을 대상으로 DNA를 추출하여, 16S rRNA 염기서열을 분석을 통해 미생물 군집을 조사하였다. 연구결과를 문(phylum)별로 구분해보면, A 토양은 전체 토양미생물이 Proteobacteria (100%) 1개의 문으로 동정되었으며, B 토양은 Actinobacteria (66.4%) > Proteobacteria (31.1%) > Bacteriodetes (2.1%) > Acidobacteria (0.3%) 순으로, C 토양은 Actinobacteria (63.1%) > Proteobacteria (36.9%) 순으로 분포하였다. 속(genus)별로 구분해보면, A 토양에서는 Pseudomonas가 98% 비율로 나타났고，B와 C 토양의 경우 Arthrobacter이 각각 68, 61%로 우점하였다. 세 군데(A, B, C) 토양 미생물 군집의 종 다양성을 Shannon 지수에 근거하여 분석한 결과, B 토양(3.45)과 C 토양(3.43)은 유사한 수준이었으나, A 토양(2.37)은 가장 낮게 계산되었다. 또한, 분석결과 Salmonella, Campylobacter 그리고 Clostridium perfringens과 같은 병원균도 발견되지 않았으나, 세균혈증을 일으키는 Ralstonia pickettii가 높은 농도로 관찰되었다. 본 연구에 사용된 가축 매몰지 토양은 침출수에 의한 미생물학적 오염도가 낮은 것으로 판단되지만, 가축매몰에 따른 병원성 미생물에 의한 토양의 잠재적 위해성을 평가하기 위하여 지속적인 모니터링이 필요하다.

• 환경영향평가
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• 제20권4호
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• pp.497-507
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• 2011

This research studied human health risk assessment of benzene from industrial complexes of Chungcheong Province (Seosan industrial complex) and Jeonla Province (Iksan industrial complex and Yeosoo industrial complex). The residents near the industrial complexes areas can be often exposed to volatile organic compounds (e.g., benzene, toluene, xylenes) through a number of exposure pathways, including inhalation of the organic pollutant via various environmental matrices (air, water and soil), contaminated water, and soil intake. Benzene is well known to be a common carcinogenic and toxic compound that is produced from industrial and oil refinery complexes. In this study, a number of samples from water, air, and soil were taken from the residential settings and public school zones located near the industrial complex sites. Based on the carcinogenic risk assessment, the risk estimates were slightly above $10{\times}10^{-6}$ at all three industrial sites. According to deterministic risk assessment, inhalation was the most important route. The distribution of benzene in the environment would be dependent on vapor pressure, and the physical property influencing the extent of the potential risks. Non-carcinogenic risk assessment of benzene shows that the values of Hazard Index(HI) were much lower than 1.0 at all industrial complexes. Therefore, benzene was not a cause of concern in terms of non-carcinogenic risk posed to the residents near the sites. When compared to probabilistic risk assessment, the CTE(central tendency exposure) cancer risk values of deterministic risk assessment were close to the mean values predicted by the probabilistic risk assessment. The RME(reasonable maximum exposure) values fell within the range of 95% to 99.9% estimated by the probabilistic risk assessment. Since the values of carcinogenic risk assessment were higher than $10{\times}10^{-6}$, further detailed monitoring and refined risk assessment for benzene may be warranted to estimate more reliable and potential inhalation risks to receptors near the industrial complexes.

• 한국지하수토양환경학회지:지하수토양환경
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• 제27권spc호
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• pp.51-63
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• 2022

In this study, the TPH(Total Petroleum Hydrocarbon) contamination and microbial ecological characteristics in petroleum-contaminated site were investigated through the correlation among the vertical TPH contamination distribution of the site, the geochemical characteristics, and the indigenous microbial ecology. The high TPH concentration showed in the vicinity of 3~4 m or less which is thought to be affected by vertical movement due to the impervious clay layer. In addition, the TPH concentration was found to have a positive correlation with Fe²⁺, TOC concentration, and the number of petroleum-degrading bacteria, and a negative correlation with the microbial community diversity. The microbial community according to the vertical distribution of TPH showed that Proteobacteria and Firmicutes at the phylum level were dominant in this study area as a whole, and they competed with each other. In particular, it was confirmed that the difference in the microbial community was different due to the difference in the degree of vertical TPH contamination. In addition, the genera Acidovorax, Leptolinea, Rugoshibacter, and Smithella appeared dominant in the samples in which TPH was detected, which is considered to be the microorganisms involved in the degradation of TPH in this study area. It is expected that this study can be used as an important data to understand the contamination characteristics and biogeochemical and microbial characteristics of these TPH-contaminated sites.

• 자원환경지질
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• 제38권6호
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• pp.657-662
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• 2005

Extractions fro fertilizer and soil samples were performed to yield the operationally defined fractions 'soluble' chromate (extractable with $NH_4NO_3$), 'exchangeable' chromate (extractable with phosphate buffer pH 7.2), and these results were compared with the data obtained by extractions with ammonium sulfate, borate buffer pH 7.2, saturated borax pH 9.6, and polyphosphate (Graham's salt). In order to maintain the pH of extractant solution about constant, the concentration of extractant buffer had to be raised to at least 0.5 M. The results strongly depended on the kind of extractant, and the solid: liquid ratio. For most of the samples investigated, the extraction efficiency increased in the order borate-sulfate-nitrate-phosphate. Whereas the recovery of $K_2CrO_4\;and\;CaCrO_4$ added to the samples of basic slags prior to the extraction was about complete, the recovery of added $PbCrO_4$ was highly variable. In soil extracts, the color reaction was interfered from co-extracted humics, which react with the chromate in weak acid solution during the time period necessary for color reaction (1 hour). However, this problem can be overcome by standard addition and subtraction of the color of the extractant solution. In soil extract of about pH < 7, organic material reduced chromate during the extraction period also, and standard addition of soluble chromate is recommended to prove recovery and the stability of chromate in the samples. In admixtures of soils and basic slags, results for hexavalent chromium were lower than from the mere basic slags. This effect was more pronounced in phosphate than in nitrate extracts. As a proficiency test, samples low in organic carbon from contaminated sites in Hungary were tested. The results from $NH_4NO_3$ extracts satisfactorily matched the results of the Hungarian labs obtained from $CalCl_2$ extractants.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 International Symposium
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• pp.70-86
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• 2003

Despite its usability, TCE has been managed as a hazardous material due to the toxicity and many contamination cases were surveyed in some developed countries. U.S.EPA(Kram et al., 2001) suggested DNAPL characterization methods and approaches based on survey experiences at several sites. However, Korea has not the least assessment of contamination and trial of remediation, although there are a lot of doubtable areas where ground water would be contaminated with TCE. In this study, we try to assess the volume and extent of ground water contamination with TCE and delineate the contamination source zones in an industrial area. Ground water in this area flows through fractures and the contaminant TCE has the properties of high volatility, high density and low partitioning to soil material. Thus, we applied a variety of technical approaches to identify the contamination status; documentary, hydrogeochemical, hydrogeological and geological surveys. In addition, additional survey was performed based on the interim findings, which showed that ground water contamination was limited to the relatively small area with high concentrations to the deep place. The contamination source zone is estimated to be the asphalt test institute where a great deal of TCE has been used to analyze the amount of asphalt soluble in TCE since 1984. Based on the contamination characterization and a myriad of documents about ground water remediation, appropriate site remediation management options will be recommended later. This study is now under way and this paper was focused on describing the technical approaches used to achieve the goals of this study.

• 한국환경생태학회지
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• 제24권3호
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• pp.279-285
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• 2010

본 연구는 중금속이 낙엽의 분해에 미치는 영향을 알아보기 위하여 충남 청양의 폐금광의 광미에 분포하는 쑥(Artemisia princeps var. orientalis)과 쇠뜨기(Equisetum arvense)를 이용하여 실험하였다. 광미는 높은 중금속 함량과 낮은 유기물 함량을 가지고 있었다. 광미의 중금속 함량은 대조구 토양에 비해 비소(As)는 약 13배, 카드뮴(Cd)은 약 28배 높은 것으로 나타났다. 또한 크롬(Cr), 니켈(Ni) 및 아연(Zn)은 약 3배에서 6배 높게 측정되었다. 광미와 대조구 토양에서 채집한 식물체내의 중금속 함량은 광미에서 채집한 식물에서 현저히 높게 나타났으며, 쑥 잎의 경우 As는 약 23배, Cd은 25배 높게 나타났으며, 쇠뜨기 지상부의 경우 As는 58배, Cd은 11배 높은 것으로 나타났다. 대조구에서 분해 결과 중금속 농도가 높은 쑥의 잎과 대조구에서 채취한 잎이 각각 50.4%, 65.7%가 분해되었다. 또한 광미에서 진행된 분해 결과 쑥의 잎은 폐광지역에서 채취한 잎과 대조구에서 채취한 잎이 각각 31.6%, 57.5%가 분해되었다. 쑥의 줄기의 분해결과도 잎의 분해율과 비슷한 양상을 나타내었다. 쇠뜨기의 지상부의 분해는 대조구에서 분해된 결과 광미에서 채집된 쇠뜨기와 대조구에서 채집한 쇠뜨기가 각각 77.8%와 89.3%가 분해되었으며, 광미지역에서 분해 결과 각각 67.6%와 82.1%가 분해된 것으로 나타났다. 따라서 광미에서 생육하는 식물체의 중금속의 함량이 높을수록 분해가 느린 것으로 나타났으며, 이는 중금속이 낙엽의 분해에 영향을 미친 것이라고 판단된다.

• 한국환경농학회지
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• 제4권2호
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• pp.88-94
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• 1985

온산(溫山)공업단지 조성(造成)에 따른 토양(土壤)의 오염(汚染)가능성을 조사하기 위하여 1978년 3월부터 1979년 5월말까지 수차에 걸쳐 공업단지 주변의 전답(田畓), 과수원 및 야산(野山)의 토양시료에 대하여 중금속 원소의 농도를 분석한 결과는 다음과 같다. 1) 농경지통양 46개지점의 중금속 농도(풍건물(風乾物) 기준)는 비소 흔적${\sim}9.3ppm$, 카드뮴 흔적${\sim}$0.6 ppm, 구리4${\sim}$22ppm, 수은 흔적${\sim}$0.37ppm, 납 6${\sim}$43ppm, 아연 27${\sim}$93ppm으로서 전국(全國) 논토양의 분석치와 비교할 때 중금속의 오염은 전혀 인정할 수 없었다. 2) 중금속 함량을 논, 밭, 과수원의 토양별로 비교한 결과 As, Cd, Cu, Zn은 토양에 따라 유의차(有意差)가 없었으나 Hg, Pb는 유의차(有意差)가 있었다. 공단내(工團內) 리단위(里單位)지역에 따른 중금속 함량을 비교한 결과 As, Cd, Hg는 유의차(有意差)가 없었으나 Cu, Pb, Zn은 유의차(有意差)가 있었다. 3) 금속제련소 인접지역에서는 아연제련소(亞鉛製鍊所)의 시운전(試運轉)중 사고에 의하여 Cd, Pb, Zn으로 오염(汚染)된 지점이 여러곳 관찰되었으나 정상가동(正常稼動)에 들어간 이후에는 오염이 더 이상 진행되지 않았다.