• Title/Summary/Keyword: benzene, toluene, and xylenes

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온도와 초기 BTEX농도변화에 따른 BTEX 분해특성

  • 장순웅;라현주;이시진
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 1999.10a
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    • pp.19-22
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    • 1999
  • A microbial consortium derived from a gasoline-contaminated sites was enriched on toluene in 100-mL serum bottle and was found to degrade benzene(B), toluene(T), ethylbenzene(EB), and xylenes(X). Studies conducted to determine the temperature effects and BTEX concentration on BTEX degradation. The results indicated that lowering temperature significantly decreased BTEX degradation rates and varing the BTEX concentration also changed substrate degradation patterns.

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Benzene, toluene, ethylbenzene 그리고 세가지 xylene isomer를 분해하는 유기용매 내성세균 Pseudomonas savastanoi BCNU 106의 분리 및 분해 특성

  • Kim, Jong-Su;Park, Hyeong-Cheol;Jo, Su-Dong;Lee, Seung-Han;Bae, Yun-Wi;Mun, Ja-Yeong;Jeong, Yeong-Gi;Ju, U-Hong
    • 한국생물공학회:학술대회논문집
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    • 2003.04a
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    • pp.382-385
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    • 2003
  • Organic solvent tolerant bacterium, designated as strain BCNU 106 is a gram negative, rod-shaped aerobe and grows on benzene, toluene, ethylbenzene, and xylenes (BTEX) as a sole carbon source. According to 16S rDNA analysis and fatty acid analysis, strain BCNU 106 showed highest similarity to Pseudomonas syringae var. savastanoi (Pseudomonas savastanoi). Strain BCNU 106 was able to utilize toluene, ethylbenzene, both o-, m-, p-xylene , m-cresol and o-cresol. The degradation of o-, m-, p-xylene by strain BCNU 106 is particularly important, since o-xylene is a compound of considerable environmental interest, owing to its recalcitrance; and very few microorganism have been reported to utilize both o-, m-, p-xylene as a sole carbon source.

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Evaluation of Volatile Organic Compounds Levels in Industrial Complex and Nearby Residential Areas of Daegu (대구지역 공단과 인근 주거지역의 휘발성유기화합물질 오염도 평가)

  • Jo, Wan Geun;Lee, Jin U
    • Journal of Environmental Science International
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    • v.13 no.6
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    • pp.519-525
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    • 2004
  • Air pollution from the Daegu industrial complex (Die) in Korea has been a common nuisance and cause of complaints for nearby residents. The current study measured the indoor and outdoor levels of six VOC (benzene, toluene, ethylbenzene, and three isomeric xylenes) at two residential areas with a different proximity to the ODIC, plus the ambient levels at two industrial areas within the boundary of the DDIC. The QA/QC program included the range of correlation coefficient (0.94-0.99) for calibration curves, within the permissible range. Toluene was the most abundant VOC in the ambient air both in residential and industrial areas. Both indoor and outdoor air concentrations of all target VOC except benzene were higher in residential area near the DIC compared to that further away from the DIC. Moreover, the ambient air concentrations of all target VOC except benzene for two industrial sites (A and B) were significantly higher than the outdoor or indoor air concentrations in the two residential areas. The findings further suggested that VOC ambient levels measured in a residential area near the DIC be used as a potential indicator of odor-causing unidentified air pollutants transported from the DIC. Moreover, it was found that the elevated ambient toluene levels outweighed the indoor sources with respect to the environmental exposure of residents nearby the DIC. However, in the residential area further away from the DIC, the toluene indoor sources outweighed the outdoor sources.

Quenching Curves for VOCs in the Analysis of Groundwater $^{14}C$ using Liquid Scintillation Counter (액체섬광계수기를 이용한 지하수의 $^{14}C$ 측정에서 휘발성유기화합물(VOC)에 대한 소광곡선)

  • Lee, Kil-Yong;Cho, Soo-Young;Yoon, Yoon-Yeol;Ko, Kyung-Seok;Kim, Yong-Je
    • Journal of Soil and Groundwater Environment
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    • v.12 no.6
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    • pp.53-59
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    • 2007
  • Optimal quenching curves have been studied for the accurate analysis of $^{14}C$ in groundwater polluted by reducing efficiency of volatile organic compounds (VOCs) in liquid scintillation counter (LSC). The quenching parameters (SQP(E)) were measured for ten VOCs such as benzene, toluene, ethylbenzene, o-(m-,p-)xylene, trichloroethylene (TCE), tetrachloroethylene(PCE), carbon tetrachloride and chloroform. The quenching curves were plotted using $^{14}C$ standard solution and chloroform as a quenching agent. Optimal plotting conditions were determined for standard solution, LSC measuring time and the concentration of chloroform. The quenching effects of chlorinated organic compounds such as TCE, PCE, carbon tetrachloride and chloroform were greater than those of BTEX (benzene, toluene, ethylbenzene and xylene). Optimum measuring time was 100 minutes far 7,000 dpm/mL standard solution. A few mL of chloroform should be added for good quenching curves. These quenching curves have good correlation coefficients (> 0.99) and the curves could be applied to accurate analysis of $^{14}C$ in groundwater and tap water.

Risk Assessment of Volatile Organic Compounds (VOCs) and Formaldehyde in Korean Public Facilities: Derivation of Health Protection Criteria Levels

  • Kim, Ho-Hyun;Lim, Young-Wook;Shin, Dong-Chun;Sohn, Jong-Ryeul;Yang, Ji-Yeon
    • Asian Journal of Atmospheric Environment
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    • v.5 no.2
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    • pp.121-133
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    • 2011
  • This study suggests criteria to conduct a risk assessment of VOCs and formaldehyde in uncontrolled public facilities. Pollutants and facilities were selected based on two years of monitoring data and exposure scenarios in 573 uncontrolled public facilities, composed of 10 types of public institutions. With the exception of social welfare facilities, lifetime ECRs of formaldehyde and benzene in each facility were higher in employees than in users, except in social welfare facilities. In social welfare facilities, the risk of benzene for users ($1{\times}10^{-5}$) was higher than that of workers ($1{\times}10^{-6}$) because facility users live in the facility 24 hours per day, compared to workers who spend an average of 8 hours per day in the facility. The risk of benzene to workers in restaurants, academies, performance halls, internet cafe and pubs were estimated as high as $1{\times}10^{-4}$ and the risk to workers in the theaters and karaoke bars were recorded as $1{\times}10^{-5}$. Because lifetime ECRs of carcinogens exceeded $1{\times}10^{-4}$ for workers and users in most facilities, risk management of formaldehyde and benzene in these facilities is necessary. Although HQs of toluene and xylenes did not exceed 1.0, their HQs did exceed 0.1 in some facilities, so they were evaluated as potentially harmful materials. Additionally, criteria for health protection in IAQ by facility are suggested at $60-100\;{\mu}g/m^3$ for formaldehyde, $400-500\;{\mu}g/m^3$ for TVOCs, $10-20\;{\mu}g/m^3$ for benzene, $150-170\;{\mu}g/m^3$ for toluene and $100\;{\mu}g/m^3$ for xylenes, based on the survey on IAQ and HRA methodology. The excess rates of IAQ to health protection criteria in all facilities were 16% for formaldehyde, 8% for TVOCs and benzene, 9% for toulene, and 5% for xylenes.

The Simultaneous Analysis of Benzene, Toluene, Ethylbenzene, o,m,p-Xylenes and Total Petroleum Hydrocarbons in Soil by GC-FID after Ultra-Sonication

  • Sin, Ho Sang;Gwon, O Seung
    • Bulletin of the Korean Chemical Society
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    • v.21 no.11
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    • pp.1101-1105
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    • 2000
  • A simultaneous determination method of BTEX (benzene, toluene, ethylbenzene, o,m.p-xylene) and TPH (kerosene, diesel, jet fuel and bunker C) in soil with gas chromatography/flame ionization detection (GC-FID) was described. The effects of extracti on method, extraction solvent, solvent volume and extraction time on the extraction performance were studied. A sonication method was simpler and more efficient than Soxhlet or shaking methods. Sonication with 10 mL of acetone/methylene chloride (1 : 1, v/v) for 10 min was found to be optimal extraction conditions for 20 g of soil. Peak shapes and quantification of BTEX and TPH were excellent, with linear calibration curves over a wide range of 1-500 mg/L for BTEX and 10-5000 mg/L for TPH. Good reproducibilities by sonication were obtained, with the RSD values below 10%. By using about 20 g of soil, detection limits were 0.8 mg/L for BTEX and 10 mg/L for TPH. The advantages of this procedure are the use of simple and common equipment, reduced volumes of organic solvents, rapid extraction periods of less than 20 min, and simultaneous analysis of volatile and semivolatile compounds.

A Study on the BTEX Ratio and Correlation of C2-benzenes in Vehicle Exhaust (자동차 배출가스 중 BTEX의 비율과 C2-benzenes의 상관성 연구)

  • Mun, Sunhee;Chung, Taekho;Jung, Sungwoon;Kim, Sunmoon;Seo, Seokjun;Lee, Seounghwan;Kim, Jounghwa;Hong, Youdeog;Hong, Heekyoung
    • Journal of ILASS-Korea
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    • v.23 no.4
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    • pp.185-191
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    • 2018
  • Benzene, toluene, ethylbenzene and xylene (BTEX) were well known as ozone precursors from photochemical reactions and contribute to the formation of photochemical smog which pose health hazards. Also, some of these compounds directly affect the human health due to their toxicity such as benzene. In this study, BTEX ratios and correlation of $C_2$-benzenes (xylenes, ethylbenzene) in vehicle exhaust from recreational vehicle (RV) and multi-purpose vehicle (MPV) were characterized using a chassis dynamometer. VOCs were collected by tedlar bag and a GC/MS system was used for their quantification. Among all of the BTEX, toluene has the highest concentration(more than 30% in composition of BTEX). The average ratio of toluene to benzene emissions (T/B ratio=2.2) was found in vehicle exhaust. The average m,p-xylene/ethylbenzene and m,p-xylene/o-xylene ratios were 1.0 and 3.0 respectively. As a result, it showed a good correlation between the $C_2$-benzenes ($R^2=0.98{\sim}0.99$). In the future, it can be used as a marker for effect evaluation to atmospheric environment by vehicle exhaust.

Identification of Volatile Organic Compounds in Several Indoor Public Places in Korea

  • Seo, Sooyun;Lim, Soogil;Lee, Kiyoung;Seo, Young-Kyo;Baek, Sung-Ok
    • Asian Journal of Atmospheric Environment
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    • v.8 no.4
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    • pp.192-201
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    • 2014
  • A comprehensive profile of volatile organic compounds (VOCs) in public spaces is needed for interpreting indoor air measurements. Seasonal differences in profiles are critical for epidemiological study and risk assessment. The purposes of this study were to establish profiles for individual VOCs in 50 indoor public places in Korea and to determine seasonal variations in their concentrations. Air samples were taken during working hours. Seventy-two of the 91 targeted VOCs were identified using multiple standards. Six VOCs detected in all summer and winter samples were toluene, acetone, m,p-xylenes, ethylbenzene, benzene, and styrene. In summer, methyl ethyl ketone and 1-butanol were also found in all samples. In both seasons, the dominant indoor VOCs were toluene, m,p-xylenes, ethylbenzene, acetone, and isopropyl alcohol. Other chemicals associated with gasoline emissions were dominant in summer. Limonene was dominant only in winter due to the consumption of tangerines. The nine VOCs with the highest concentrations comprised 64.8% and 49.6% of the TVOC in summer and winter, respectively. Comparing two types of adsorbent tube, a single adsorbent tube with Tenax-TA had similar detection performance as a double adsorbent tube with Tenax and Carbotrap.

Degradation of TPHs, TCE, PCE, and BTEX Compounds for NAPLs Contaminated Marine Sediments Using In-Situ Air Sparging Combined with Vapor Extraction (증기추출법과 결합된 공기주입법을 이용한 비수용성액체 해양퇴적물의 TPHs, TCE, PCE 및 BTEX 정화)

  • Lee, Jun-Ho;Han, Sun-Hyang;Park, Kap-Song
    • Economic and Environmental Geology
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    • v.46 no.5
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    • pp.425-444
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    • 2013
  • This study was carried out in order to determine the remediation of total petroleum hydrocarbons (TPHs), trichloroethylene (TCE), perchloroethylene (PCE), benzene, toluene, ethylbenzene and xylenes (BTEX) compounds for non-aqueous phase liquids (NAPLs) using in-situ air sparging (IAS) / vapor extraction (VE) with the marine sediments of Mandol, Hajeon, Sangam and Busan, South Korea. Surface sediment of Mandol area had sand characteristics (average particle size, 1.789 ${\Phi}$), and sandy silt characteristics (average particle size, 5.503 ${\Phi}$), respectively. Sangam surface sediment had silt characteristics (average particle size, 5.835 ${\Phi}$). Sediment characteristics before experiment in the Busan area showed clay characteristics (average particle size, 8.528 ${\Phi}$). TPHs level in the B1 column of Mandol, Hajeon, Sangam, and Busan sediments were 2,459, 6,712, 4,348, and 14,279 ppm. B2 (3 L/min) to B5 (5 L/min) columns reduced 99.5% to 100.0% of TCE and 93.2% to 100.0% of PCE. Removal rates of TCE, PCE, and BTEX are closely correlated (0.90-0.99) with particle sizes and organic carbon concentrations. However, TPHs (0.76) and benzene (0.71) showed the poorer but moderate correlations with the same parameters.

Construction and Evaluation of Cryogenic Preconcentration System for Analysis of VOC with ppb Level in the Air (대기 중의 ppb 농도의 VOC의 분석을 위한 저온농축장치의 제작과 성능평가)

  • Jeon, Sun Joo;Kim, Byung Joo;Kim, Jin Seog;Heo, Gwi Suk
    • Analytical Science and Technology
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    • v.12 no.4
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    • pp.332-340
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    • 1999
  • Homemade cryogenic preconcentration system is constructed to preconcentrate the VOCs in the ambient air collected in canister. Homemade preconcentrator equipped with GC-MS was used for analysis of air sample containing VOCs at ppb level identified in EPA TO-14 method. The system was evaluated for analytical performance by comparison with the results of adsorption tube method widely used in the past, and shows good agreement for concentrations of benzene, toluene, ethylbenzene, and xylenes.

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