Intrinsic bioremediation of gas condensate hydrocarbons

Condensate liquids have been found to contaminate soil and ground water at two gas production sites in the Denver Basin operated by Amoco Production Co. These sites have been closely monitored since July 1993 to determine whether intrinsic aerobic or anaerobic bioremediation of hydrocarbons occurs at a sufficient rate and to an adequate end point to support a no-intervention decision. Ground water monitoring, soil gas analysis, and analysis of soil cores suggest that bioremediation is occurring at these sites by multiple pathways, including aerobic oxidation, sulfate reduction, and methanogenesis. Results of over two years of monitoring of ground water and soil chemistry at these sites are presented to support this conclusion.

     

The potential for intrinsic bioremediation of BTEX hydrocarbons in soil/ground water contaminated with gas condensate

Applied Biochemistry and Biotechnology - Gas condensate liquids contaminate soil and ground water at two gas production sites in the Denver Basin, CO. A detailed field study was carried out at...     

A case study of the natural attenuation of gas condensate hydrocarbons in soil and groundwater

Applied Biochemistry and Biotechnology - Condensate liquids have been found to contaminate soil and groundwater at two gas production sites in the Denver Basin operated by Amoco Production Co....     

Increase in removal of polycyclic aromatic hydrocarbons during bioremediation of crude oil-contaminated sandy soil

A 2³ full factorial experimental design was adopted to estimate the effects of three variables on the biodegradation of oil during soil bioremediation: bioaugmentation seeding a mixed culture, addition of fertilizer or mineral media, and correction of initial pH of the soil to 7.0. The tests were carried out in polyvinyl chloride reactors with 5.0 kg of crude oil-contaminated soil at 14 g/kg. After screening the variables, soil bioremediation tests were conduced with varied C:N ratios, yielding an increase in biodegradation of the oil heavy fraction from 24 to 65%, consumption of total n-paraffins, and a remarkable decrease in the concentration of residual polycyclic aromatic hydrocarbons of the soil.     

Eigenvalues of saturated hydrocarbons

A simplified Hückel-type molecular-orbital (MO) model for the valence electrons of saturated hydrocarbons is proposed and the consequent eigenvalue spectrum considered. A first foundational result is obtained, which every chemist “knows”, namely that: alkanes are stable, with half their (Hückel-type MO) eigenvalues positive and half negative.     

Functionalization of saturated hydrocarbons

Alkanes and cycloalkanes (isobutane, butane, isopentane, isohexane, and methylcyclopentane) react with benzene or bromobenzene at 0–20 °C in the presence of RCO⁺Al₂X₇ ^– complexes (R=Me, Pr, or Ph; X=Cl or Br) to give products of the alkylacylation of arenes. The yields of alkylated aromatic ketones reach 60–87 % in 5–30 min, whereas the yields of unalkylated aromatic ketones (the competitive reaction) reach 0–40 %. The reactions of isobutane or isopentane with benzene result exclusively inpara isomers oft-BuC₆H₄COR or a mixture of Me₂(Et)CC₆H₄COR and Me(i-Pr)CHC₆H₄COR isomers (11), respectively. The reaction of isobutane with benzene also proceeds regioselectively and gives only one isomer, 2-Br-t-BuC₆H₄COR.For Part 2 seeIzv. Akad. Nauk, Ser. Khim., 1991, No 1, 105 [Bull. Acad. Sci. USSR. Div. Chem. Sci., 1991, No 1, 90 (Engl. Transl)].Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1253–1257, July, 1993.The authors express their gratitude to B. I. Bakhmutov for his assistance in interpreting the spectra.     

Polycyclic aromatic hydrocarbons with mass number 300 and 302 in hard-coal flue gas condensate

Summary The emission condensate from hard-coal fired residential furnaces contains a number of PAH's of mass numbers 300 and 302 which have earlier been shown to be carcinogenic upon topical application to the skin of mice. TLC and HPLC of this particular fraction resulted in the isolation of 18 PAH's which were characterized by GC, MS, UV and fluorescence analysis. Eleven out of these could be unambiguously identified by comparison with synthetic standards, and possible structures are discussed for the remaining ones. PAH's not previously identified in combustion effluents include dibenzo(b,k)fluoranthene, naphtho(2,3-b)fluoranthene, naphtho(2,3-k)fluoranthene, naphtho(1,2-k)fluoranthene, benzo(b)perylene, naphtho(2,1-a)pyrene and naphtho(2,3-e)pyrene. However, the species responsible for the carcinogenicity of this PAH fraction remains elusive. A number of fluoranthene homologs, including the new naphtho(1,2-k)fluoranthene, were synthesized, and their UV and fluorescence spectra are discussed in an attempt to identify unknown components. The anomalous GC retention behaviour of the mass 302 compounds is pointed out.

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Polycyclische aromatische Kohlenwasserstoffe der Molmassen 300 und 302 in Steinkohle-EmissionskondensatenTeilweise Identifizierung durch Spektrometrie und unabhängige Synthese

Zusammenfassung Das Emissionskondensat von Steinkohle-beheizten Zimmeröfen enthält eine größere Zahl von PAH's der Molmassen 300 und 302, die sich in vorausgegangenen Tierversuchen an Mäusen als carcinogen erwiesen. Durch TLC und HPLC wurden aus dieser PAH-Fraktion 18 Einzelverbindungen isoliert, die durch GC, MS, UV und Fluorescenz charakterisiert wurden. Elf dieser Verbindungen konnten durch Vergleich mit synthetischen Reinsubstanzen eindeutig identifiziert werden, und für die verbleibenden werden Strukturvorschläge erarbeitet. Folgende PAH's wurden erstmals in Verbrennungsemissionen nachgewiesen: Dibenzo(b,k)fluoranthen, Naphtho(2,3-b)fluoranthen, Naphtho(2,3-k)fluoranthen, Naphtho(1,2-k)fluoranthen, Benzo(b)perylen, Naphtho(2,1-a)pyren und Naphtho(2,3-e)pyren. Welche Spezies für die Carcinogenität dieser PAH-Fraktion verantwortlich ist, konnte nicht ermittelt werden. Mehrere Fluoranthen-Abkömmlinge, darunter das bislang unbekannte Naphtho(1,2-k)fluoranthen, wurden synthetisiert; ihre UV- und Fluorescenzspektren werden im Hinblick auf die strukturelle Zuordnung unbekannter Komponenten diskutiert. Auf das ungewöhnliche GC-Retentionsverhalten der PAH's mit Molmasse 302 wird hingewiesen.

     

Characterization of complex hydrocarbons in cigarette smoke condensate by gas chromatography-mass spectrometry and comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry

Gas chromatography-mass spectrometry with electron ionization and positive-ion chemical ionization and comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC x GC-TOF-MS) were applied for the characterization of the chemical composition of complex hydrocarbons in the non-polar neutral fraction of cigarette smoke condensates. Automated data processing by TOF-MS software combined with structured chromatograms and manual review of library hits were used to assign the components from GC x GC-TOF-MS analysis. The distributions of aliphatic hydrocarbons and aromatics were also investigated. Over 100 isoprenoid hydrocarbons were detected, including carotene degradation products, phytadiene isomers and carbocyclic diterpenoids. A total of 1800 hydrocarbons were tentatively identified, including aliphatic hydrocarbons, aromatics, and isoprenoid hydrocarbons. The identified hydrocarbons by GC x GC-TOF-MS were far more than those by GC-MS.     

高效液相色谱-气相色谱在线联用同时测定土壤中饱和烃和芳香烃

为加强对土壤中石油烃类污染物的风险管控,生态环境部已将石油烃类列为土壤中的重点监测项目.石油烃源于石油与合成油,是涵盖一定碳数范围的碳氢化合物,主要分为饱和烃和芳香烃两大类.芳香烃通常是高度烷基化的单环、双环与多环芳烃,其对人和动物的毒性较饱和烃大很多,因此,仅仅测定土壤中总石油烃含量难以准确评估其环境毒性.目前环境领...     

Potential use of cyclodextrins in soil bioremediation

Bioavailability and toxic effect of contaminants are the main limitations during soil bioremediation. Cyclodextrins may influence bioavailability of the contaminants during biodegradation and also toxicity of the pollutant on soil microbes and plants since their ability to form inclusion complei with organic compounds. The effect of cyclodextrins on bioremediation and on toxic effect of hydrocarbons was investigated by testing the activity of hydrocarbon degrading microflora and of plant growth. The effect of cyclodextrins could be demonstrated in both cases: biodegradation of hydrocarbons could be enhanced and toxic effect of hydrocarbons on plants and soil microbes could be decreased by adding cyclodextrins.     

全二维气相色谱-飞行时间质谱分析焦化柴油中饱和烃的分子组成

建立了全二维气相色谱-飞行时间质谱(GC×GC-TOF MS)分析柴油馏分中饱和烃的分子组成的方法。结合谱库检索、质谱图解析、沸点与分子结构关系和全二维谱图特征,定性(或归类)了焦化柴油饱和烃组分中1057个化合物单体,其中正构烷烃排列规律性最强,一环~三环环烷烃按照极性和沸点的差异呈瓦片状分布在其上方。另外,还准确区分了在一维气相色谱上共流出的正构烷基环己烷和正构烷基环戊烷,以及正构 α 单烯烃。根据质谱采集的总离子流色谱图,采用峰面积归一化法得到了饱和烃组分的碳数分布结果,并将该方法应用于研究不同类型柴油馏分饱和烃的分子组成特点。结果表明,催化裂化和焦化柴油馏分饱和烃组分的化合物类型和分布各不相同。分子组成分析能为油品加工工艺机理的研究提供方法支持。     

Functionalization of saturated hydrocarbons by aprotic superacids

The inefficient formylation of adamantane by CO initiated by superacid systems based on polyhalomethanes and aluminum halides becomes selective in the presence of methylcyclopentane and affords 1-adamantanecarbaldehyde in an almost quantitative yield under mild conditions.     

Bioenergetics and bioremediation of contaminated soil

The microbial biodegradation of xenobiotic compounds in soil and ground water is constrained by the laws of thermodynamics. Bioremediation is being investigated in a rhizosphere environment in which higher plants provide carbon and energy to sustain the microbial population. Toluene, phenol, trichloroethylene and trichloroethane have been fed in separate experiments to a pilot scale system with alfalfa growing in sandy soil containing less than 10% of silt. It is well known that microbial populations are numerous in the root zone of healthy vegetation. Root exudates can stimulate aerobic microbial biodegradation of compounds which by themselves support growth poorly or not at all. Polynuclear aromatic compounds such as phenanthrene, anthracene, and pyrene, which are not very soluble in water, and chlorinated aliphatic hydrocarbons such as trichloroethylene are examples of compounds that can be biodegraded in the rhizosphere when root exudates are present to enhance and sustain microbial activity. Solar driven transport processes such as water and solute movements due to evapotranspiration increase the likelihood that the contaminants will come into contact with the microorganisms and be degraded. The thermodynamic and bioenergetic aspects of transport and biodegradation in the rhizosphere are examined through a review of the literature and the analysis of experimental data collected in the pilot scale system.