WorldWideScience

Sample records for chlorinated hydrocarbon degradation

  1. Radiolytic degradation of chlorinated hydrocarbons in water

    International Nuclear Information System (INIS)

    Radiolytic degradation of chlorinated hydrocarbons (chloroform, trichloroethylene, and tetrachloroethylene) in water was carried out. Water solutions of the chlorinated hydrocarbons with different concentrations were irradiated with γ rays. Concentrations of methane, ethane, CO, CO2, H2, and O2 after the irradiation were determined by gas chromatography. Concentration of chloride ion in the irradiated sample was determined by ion chromatography. Experimental results show that radiolytic degradation of the chlorinated hydrocarbon increased with the radiation dose. Methane, ethane, CO2, H2, and Cl- concentrations increased with the radiation dose and the sample concentration. On the other hand, O2 concentration decreased with the radiation dose and the sample concentration. When sample concentration was high, dissolved oxygen might be not enough for converting most of the C atoms in the sample into CO2. This resulted in a low decomposition ratio. Addition of H2O2 as an oxygen resource could increase the decomposition ratio greatly. Furthermore, gas chromatography-mass spectroscopy was applied to identify some intermediates of the radiolytic dehalogenation. Radiolytic degradation mechanisms are also discussed. (author)

  2. Anaerobic Degradation of Chlorinated Hydrocarbons in Groundwater Aquifers or "Chlorinated Hydrocarbon Degradation"

    OpenAIRE

    Nielsen, R. Brent; Jay D Keasling

    1997-01-01

    Groundwater contamination by chlorinated hydrocarbons, such as tetrachloroethene (PCE) or trichloroethene (TCE), is a major concern throughout the United States. A developing strategy for the remediation of PCE and TCE contaminated aquifers is anaerobic biodegradation. From a TCE contaminated groundwater site, microorganisms were enriched with the ability to anaerobically convert PCE and TCE completely to ethene. Kinetic studies performed with this culture showed that degradation of PCE, TCE...

  3. Kinetics of Chlorinated Hydrocarbon Degradation by Methylosinus trichosporium OB3b and Toxicity of Trichloroethylene

    NARCIS (Netherlands)

    Oldenhuis, Roelof; Oedzes, Johannes Y.; Waarde, Jacob J. van der; Janssen, Dick B.

    1991-01-01

    The kinetics of the degradation of trichloroethylene (TCE) and seven other chlorinated aliphatic hydrocarbons by Methylosinus trichosporium OB3b were studied. All experiments were performed with cells grown under copper stress and thus expressing soluble methane monooxygenase. Compounds that were re

  4. Kinetics of chlorinated hydrocarbon degradation by Methylosinus trichosporium OB3b and toxicity of trichloroethylene.

    OpenAIRE

    Oldenhuis, Roelof; Oedzes, Johannes Y.; Waarde, Jacob J. van der; Janssen, Dick B.

    1991-01-01

    The kinetics of the degradation of trichloroethylene (TCE) and seven other chlorinated aliphatic hydrocarbons by Methylosinus trichosporium OB3b were studied. All experiments were performed with cells grown under copper stress and thus expressing soluble methane monooxygenase. Compounds that were readily degraded included chloroform, trans-1,2-dichloroethylene, and TCE, with V(max) values of 550, 330, and 290 nmol min-1 mg of cells-1, respectively. 1,1-Dichloroethylene was a very poor substra...

  5. Chromatographic study of gamma-ray irradiated degradation of chlorinated hydrocarbon in water

    International Nuclear Information System (INIS)

    Degradation of chlorinated hydrocarbon in gamma ray irradiation was examined in order to get information on treatment of groundwater. Water chloroform was sealed into a vial irradiated with gamma ray. Both gas chromatography and ion chromatography were applied for determination of degradation products. Carbon dioxide, carbon monoxide, methane, ethane and chloride ion were detected in the irradiated system. Effect of radiation dose on the gamma ray induced chloroform degradation was investigated. The elimination of chloride ion and the degradation of chloroform were promoted by gamma irradiation in a dose-dependent manner. The G(CHCl3), which was defined as the number of degraded chloroform molecules when absorbed 100eV, was inferred to be 3.1. The degradation mechanism of chloroform irradiated with gamma ray seemed to involve that chloroform reacted with electron from radiolysis of water and the elimination of chloride ion occurred. (author)

  6. Synergistic degradation of chlorinated hydrocarbons with microorganisms and zero valent iron

    Science.gov (United States)

    Schöftner, Philipp; Summer, Dorothea; Leitner, Simon; Watzinger, Andrea; Wimmer, Bernhard; Reichenauer, Thomas

    2016-04-01

    Sites contaminated with chlorinated hydrocarbons (CHC) are located mainly within build-up regions. Therefore in most cases only in-situ technologies without excavation of soil material can be used for remediation. This project examines a novel in-situ remediation method, in which the biotic degradation via bacteria is combined with abiotic degradation via zero-valent iron particles (ZVI). ZVI particles are injected into the aquifer where CHC-molecules are reductively dechlorinated. However Fe0 is also oxidized by reaction with water leading to generation of H2 without any CHC degradation. To achieve biotic degradation often strictly anaerobic strains of the bacteria Dehalococcoides are used. These bacteria can dechlorinate CHC by utilizing H2. By combining these processes the H2, produced during the anaerobic corrosion of Fe0, could be used by bacteria for further CHC degradation. Therefore the amount of used Fe0 and as a consequence also remediation costs could be reduced. Additionally the continuous supply of H2 could make the bacterial degradation more controllable. Different Fe0 particles (nano- and micro-scale) were tested for their perchloroethene (PCE) degradation rate and H2 production rate in microcosms. PCE-degradation rate by different bacterial cultures was investigated in the same microcosm system. In course of these experiments the 13C enrichment factors of the PCE degradation of the different particles and cultures were determined to enable the differentiation of biotic and abiotic degradation. Preliminary results showed, that the nano-scale particles reacted faster with PCE and water than their micro-scaled counterparts. The PCE degradation via micro-scaled particles lead to 13C enrichment factors in the range of -3,6 ‰ ± 0,6 to -9,5 ‰ ± 0,2. With one of the examined bacterial cultures a fast reduction of PCE to ethene was observed. Although PCE and TCE were completely degraded by this culture the metabolites DCE and VC could still be detected

  7. Degradation kinetics of chlorinated aliphatic hydrocarbons by methane oxidizers naturally-associated with wetland plant roots.

    Science.gov (United States)

    Powell, C L; Goltz, M N; Agrawal, A

    2014-12-01

    Chlorinated aliphatic hydrocarbons (CAHs) are common groundwater contaminants that can be removed from the environment by natural attenuation processes. CAH biodegradation can occur in wetland environments by reductive dechlorination as well as oxidation pathways. In particular, CAH oxidation may occur in vegetated wetlands, by microorganisms that are naturally associated with the roots of wetland plants. The main objective of this study was to evaluate the cometabolic degradation kinetics of the CAHs, cis-1,2-dichloroethene (cisDCE), trichloroethene (TCE), and 1,1,1-trichloroethane (1,1,1TCA), by methane-oxidizing bacteria associated with the roots of a typical wetland plant in soil-free system. Laboratory microcosms with washed live roots investigated aerobic, cometabolic degradation of CAHs by the root-associated methane-oxidizing bacteria at initial aqueous [CH4] ~1.9mgL(-1), and initial aqueous [CAH] ~150μgL(-1); cisDCE and TCE (in the presence of 1,1,1TCA) degraded significantly, with a removal efficiency of approximately 90% and 46%, respectively. 1,1,1TCA degradation was not observed in the presence of active methane oxidizers. The pseudo first-order degradation rate-constants of TCE and cisDCE were 0.12±0.01 and 0.59±0.07d(-1), respectively, which are comparable to published values. However, their biomass-normalized degradation rate constants obtained in this study were significantly smaller than pure-culture studies, yet they were comparable to values reported for biofilm systems. The study suggests that CAH removal in wetland plant roots may be comparable to processes within biofilms. This has led us to speculate that the active biomass may be on the root surface as a biofilm. The cisDCE and TCE mass losses due to methane oxidizers in this study offer insight into the role of shallow, vegetated wetlands as an environmental sink for such xenobiotic compounds.

  8. Effect of reduced iron on the degradation of chlorinated hydrocarbons in contaminated soil and ground water: A review of publications

    Science.gov (United States)

    Vodyanitskii, Yu. N.

    2014-02-01

    Chlorinated hydrocarbons are among the most hazardous organic pollutants. The traditional remediation technologies, i.e., pumping of contaminated soil- and groundwater and its purification appear to be costly and not very efficient as applied to these pollutants. In the last years, a cheaper method of destroying chlorine-replaced hydrocarbons has been used based on the construction of an artificial permeable barrier, where the process develops with the participation of in situ bacteria activated by zerovalent iron. The forced significant decrease in the redox potential (Eh) down to -750 mV provides the concentration of electrons necessary for the reduction of chlorinated hydrocarbons. A rise in the pH drastically accelerates the dechlorination process. In addition to chlorine-organic compounds, ground water is often contaminated with heavy metals. The influence of the latter on the effect of zerovalent iron may be different: both accelerating its degradation (Cu) and inhibiting it (Cr). Most of the products of zerovalent iron corrosion, i.e., green rust, magnetite, ferrihydrite, hematite, and goethite, weaken the efficiency of the Fe0 barrier by mitigating the dechlorination and complicating the water filtration. However, pyrrhotite FeS, on the contrary, accelerates the dechlorination of chlorine hydrocarbons.

  9. Quantification of Degradation of Chlorinated Hydrocarbons in Saturated Low Permeability Sediments Using Compound-Specific Isotope Analysis.

    Science.gov (United States)

    Wanner, Philipp; Parker, Beth L; Chapman, Steven W; Aravena, Ramon; Hunkeler, Daniel

    2016-06-01

    This field and modeling study aims to reveal if degradation of chlorinated hydrocarbons in low permeability sediments can be quantified using compound-specific isotope analysis (CSIA). For that purpose, the well-characterized Borden research site was selected, where an aquifer-aquitard system was artificially contaminated by a three component chlorinated solvent mixture (tetrachloroethene (PCE) 45 vol %, trichloroethene (TCE) 45 vol %, and chloroform (TCM) 10 vol %). Nearly 15 years after the contaminant release, several high-resolution concentration and CSIA profiles were determined for the chlorinated hydrocarbons that had diffused into the clayey aquitard. The CSIA profiles showed large shifts of carbon isotope ratios with depth (up to 24‰) suggesting that degradation occurs in the aquitard despite the small pore sizes. Simulated scenarios without or with uniform degradation failed to reproduce the isotope data, while a scenario with decreasing degradation with depth fit the data well. This suggests that nutrients had diffused into the aquitard favoring stronger degradation close to the aquifer-aquitard interface than with increasing depth. Moreover, the different simulation scenarios showed that CSIA profiles are more sensitive to different degradation conditions compared to concentration profiles highlighting the power of CSIA to constrain degradation activities in aquitards. PMID:27153381

  10. Fenton process for degradation of selected chlorinated aliphatic hydrocarbons exemplified by trichloroethylene, 1,1-dichloroethylene and chloroform

    Institute of Scientific and Technical Information of China (English)

    Zhimin QIANG; Weiwei BEN; ChinPao HUANG

    2008-01-01

    The degradation of selected chlorinated ali-phatic hydrocarbons (CAHs) exemplified by trichloroethy-lene (TCE), 1,1-dichloroethylene (DCE), and chloroform (CF) was investigated with Fenton oxidation process. The results indicate that the degradation rate was primarily affected by the chemical structures of organic contami-nants. Hydroxyl radicals (·OH) preferred to attack the organic contaminants with an electron-rich structure such as chlorinated alkenes (i.e., TCE and DCE). The dosing mode of Fenton's reagent, particularly of Fe2+, significantly affected the degradation efficiency of studied organic compound. A new "time-squared" kinetic model, C = Coexp(-kobst2), was developed to express the degrada-tion kinetics of selected CAHs. This model was applicable to TCE and DCE, but inapplicable to CF due to their varied reaction rate constants towards ·OH. Chloride release was monitored to examine the degree of dechlorina- tion during the oxidation of selected CAHs. TCE was more easily dechlorinated than DCE and CF. Dichloroacetic acid (DCAA) was identified as the major reaction intermediate in the oxidation of TCE, which could be completely removed as the reaction proceeded. No reaction intermedi- ates or byproducts were identified in the oxidation of DCE and CF. Based on the identified intermediate, the reaction mechanism of TCE with Fenton's reagent was proposed.

  11. Chlorinated Hydrocarbon Degradation in Plants: Mechanisms and Enhancement of Phytoremediation of Groundwater Contamination

    Energy Technology Data Exchange (ETDEWEB)

    Stuart Strand

    2004-09-27

    The research objectives for this report are: (1) Transform poplar and other tree species to extend and optimize chlorinated hydrocarbon (CHC) oxidative activities. (2) Determine the mechanisms of CHC oxidation in plants. (3) Isolate the genes responsible for CHC oxidation in plants. We have made significant progress toward an understanding of the biochemical mechanism of CHC transformation native to wild-type poplar. We have identified chloral, trichloroethanol, trichloroacetic acid, and dichloroacetic acid as products of TCE metabolism in poplar plants and in tissue cultures of poplar cells.(Newman et al. 1997; Newman et al. 1999) Use of radioactively labeled TCE showed that once taken up and transformed, most of the TCE was incorporated into plant tissue as a non-volatile, unextractable residue.(Shang et al. 2001; Shang and Gordon 2002) An assay for this transformation was developed and validated using TCE transformation by poplar suspension cells. Using this assay, it was shown that two different activities contribute to the fixation of TCE by poplar cells: one associated with cell walls and insoluble residues, the other associated with a high molecular weight, heat labile fraction of the cell extract, a fixation that was apparently catalyzed by plant enzymes.

  12. Geological and hydrogeological features affecting migration, multi-phase partitioning and degradation of chlorinated hydrocarbons through unconsolidated porous media.

    OpenAIRE

    Filippini, Maria

    2015-01-01

    Chlorinated solvents are the most ubiquitous organic contaminants found in groundwater since the last five decades. They generally reach groundwater as Dense Non-Aqueous Phase Liquid (DNAPL). This phase can migrate through aquifers, and also through aquitards, in ways that aqueous contaminants cannot. The complex phase partitioning to which chlorinated solvent DNAPLs can undergo (i.e. to the dissolved, vapor or sorbed phase), as well as their transformations (e.g. degradation), depend on the...

  13. Degradation of Chlorinated Aliphatic Hydrocarbons by Methylosinus trichosporium OB3b Expressing Soluble Methane Monooxygenase

    NARCIS (Netherlands)

    Oldenhuis, Roelof; Vink, Ruud L.J.M.; Janssen, Dick B.; Witholt, Bernard

    1989-01-01

    Degradation of trichloroethylene (TCE) by the methanotrophic bacterium Methylosinus trichosporium OB3b was studied by using cells grown in continuous culture. TCE degradation was a strictly cometabolic process, requiring the presence of a cosubstrate, preferably formate, and oxygen. M. trichosporium

  14. Transformation of Chlorinated Hydrocarbons on Synthetic Green Rusts

    Science.gov (United States)

    Green rusts (GRs) are layered double hydroxides that contain both ferrous and ferric ions in their structure. GRs can potentially serve as a chemical reductant for degradation of chlorinated hydrocarbons. GRs are found in zerovalent iron based permeable reactive barriers and in c...

  15. Hydrochloric acid recycling from chlorinated hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Sowieja, D. [Sulzer Escher Wyss GmbH, Ravensburg (Germany); Schaub, M. [Sulzer Chemtech Ltd., Winterthur (Switzerland)

    1993-12-31

    Chlorinated hydrocarbons present a major ecological hazard since most of them are only poorly biodegradable. Incineration is an economical process for their destruction, however the usually recovered sodium or calcium chlorides do not present a value and their disposal may even be very costly. Recovery of hydrochloric acid may therefore present an economical solution, mainly were large quantities of highly chlorinated compounds can be processed (author) 6 refs., 4 figs., 1 tab.

  16. Behavioral toxicology, risk assessment, and chlorinated hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Evangelista de Duffard, A.M.; Duffard, R. [Laboratorio de Toxicologia Experimental, Santa Fe (Argentina)

    1996-04-01

    Behavioral end points are being used with greater frequency in neurotoxicology to detect and characterize the adverse effects of chemicals on the nervous system. Behavioral measures are particularly important for neurotoxicity risk assessment since many known neurotoxicants do not result in neuropathology. The chlorinated hydrocarbon class consists of a wide variety of chemicals including polychlorinated biphenyls, clioquinol, trichloroethylene, hexachlorophene, organochlorine insecticides (DDT, dicofol, chlordecone, dieldrin, and lindane), and phenoxyherbicides. Each of these chemicals has effects on motor, sensory, or cognitive function that are detectable using functional measures such as behavior. Furthermore, there is evidence that if exposure occurs during critical periods of development, many of the chlorinated hydrocarbons are developmental neurotoxicants. Developmental neurotoxicity is frequently expressed as alterations in motor function or cognitive abilities or charges in the ontogeny of sensorimotor reflexes. Neurotoxicity risk assessment should include assessments of the full range of possible neurotoxicological effects, including both structural and functional indicators of neurotoxicity. 121 refs., 1 tab.

  17. Catalytic hydrogen-chlorine exchange between chlorinated hydrocarbons under oxygen-free conditions

    NARCIS (Netherlands)

    van der Heijden, A.W.A.M.; Podkolzin, S.G.; Jones, M.E.; Bitter, J.H.; Weckhuysen, B.M.

    2008-01-01

    Chlorinated hydrocarbons (CHCs) remain important industrial chemical intermediates and solvents, especially for the exploration of the potential of La-based materials for the conversion of chlorinated waste compounds.[1] The production of industrially important CHCs frequently occurs with concurrent

  18. Riverine input of chlorinated hydrocarbons in the coastal pollution

    Digital Repository Service at National Institute of Oceanography (India)

    Sarkar, A.; Everaarts, J.M.

    of various chlorinated hydrocarbons. It deals with an in-depth analysis of pollution of the coastal ecosystem around the Netherlands, U.K. and Germany due to inputs of contaminants from the rivers namely, Elbe, Weser, Ems Ijssel, Rhine, Meuse, Scheldt, Thames...

  19. Electrochemical reduction characteristics and the mechanism of chlorinated hydrocarbons at the copper electrode

    Institute of Scientific and Technical Information of China (English)

    XU Wenying; GAO Tingyao; ZHOU Rongfeng; MA Lumin

    2007-01-01

    The electrochemical reduction characteristies of chlorinated hyrdrocarbons were investigated by cyclic voltammetry technique.The reduction mechanism and activity of the chlorinated hydrocarbons at the copper electrode were explored.The relationship between the structure of chlorinated hydrocarbons and their reductive activity were discussed.The experimental results showed that chlorinated alkanes and a portion of chlorinated aromatic hydrocarbons could be reduced directly at the copper electrode.However,chlorinated aromatic hydrocarbons were not easy to reduce at the copper electrode.The results provided a theoretical basis for the catalyzed iron inner electrolysis method.

  20. Kinetics of aerobic cometabolic biodegradation of chlorinated and brominated aliphatic hydrocarbons: A review.

    Science.gov (United States)

    Jesus, João; Frascari, Dario; Pozdniakova, Tatiana; Danko, Anthony S

    2016-05-15

    This review analyses kinetic studies of aerobic cometabolism (AC) of halogenated aliphatic hydrocarbons (HAHs) from 2001-2015 in order to (i) compare the different kinetic models proposed, (ii) analyse the estimated model parameters with a focus on novel HAHs and the identification of general trends, and (iii) identify further research needs. The results of this analysis show that aerobic cometabolism can degrade a wide range of HAHs, including HAHs that were not previously tested such as chlorinated propanes, highly chlorinated ethanes and brominated methanes and ethanes. The degree of chlorine mineralization was very high for the chlorinated HAHs. Bromine mineralization was not determined for studies with brominated aliphatics. The examined research period led to the identification of novel growth substrates of potentially high interest. Decreasing performance of aerobic cometabolism were found with increasing chlorination, indicating the high potential of aerobic cometabolism in the presence of medium- and low-halogenated HAHs. Further research is needed for the AC of brominated aliphatic hydrocarbons, the potential for biofilm aerobic cometabolism processes, HAH-HAH mutual inhibition and the identification of the enzymes responsible for each aerobic cometabolism process. Lastly, some indications for a possible standardization of future kinetic studies of HAH aerobic cometabolism are provided. PMID:26874310

  1. Aerobic Biodegradation of Chlorinated Hydrocarbons by Bacillus circulans WZ-12 CCTCC M 207006 under Saline Conditions

    Institute of Scientific and Technical Information of China (English)

    YU Jianming; CAI Wenji; ZHAO Shiliang; WANG Yan; CHEN Jianmeng

    2013-01-01

    A novel saline-tolerant bacterium Bacillus circulans WZ-12 was evaluated for its potential to degrade four chlorinated hydrocarbons under saline conditions.CH2Cl2 was effectively degraded by Bacillus circulans WZ-12 cells in the medium containing NaC1 concentrations ranging from 5 g·L-1 to 10 g·L-1,and the maximum degradation efficiency (85%) was achieved at NaCl concentration of 10 g·L-.Similarly,Bacillus circulans WZ-12was able to degrade CH2BtCl,C2H4Cl2,and C2H2Cl2 in the presence of 10 g NaCl per liter within 24 h.Cells of Bacillus circulans WZ-12 grown in minimal salt medium contained low levels of glycine betaine (GB),but GB levels were 3-to 5-fold higher in cells grown in media with high salt.Kinetic analysis revealed that biodegradation of the four chlorinated hydrocarbons was concentration dependent and a linear inverse correlation (R2=0.85-0.94)was observed between the rate of biodegradation (Ⅴ) and salt concentration from 5 g·L-1 to 60 g·L-1.The growing cells (in minimal salt medium) degraded approximately 50% of the CH2Cl2 within 24 h,whereas the resting cells (in physiological saline) degraded only 25% of the CH2Cl2 within 24 h and were inactive after 36 h cultivation.Biodegradation could be repeatedly performed for more than 192 h with more than 50% removal efficiency.Bacillus circulans WZ-12 grows well in an aqueous/oil system,hence,it is effective for the treatment of industrial effluents that contain chlorinated hydrocarbons with high salt concentrations.

  2. Environmental Behavior, Sources, and Effects of Chlorinated Polycyclic Aromatic Hydrocarbons

    Directory of Open Access Journals (Sweden)

    Takeshi Ohura

    2007-01-01

    Full Text Available The environmental sources and behaviors of chlorinated 2- to 5-ring polycyclic aromatic hydrocarbons (ClPAHs. ClPAHs are ubiquitous contaminants found in urban air, vehicle exhaust gas, snow, tap water, and sediments. The concentrations of ClPAHs in each of these environments are generally higher than those of dioxins but markedly lower than the concentrations of the parent compounds, PAHs. Environmental data and emission sources analysis for ClPAHs reveal that the dominant process of generation is by reaction of PAHs with chlorine in pyrosynthesis. This secondary reaction process also occurs in aquatic environments. Certain ClPAHs show greater toxicity, such as mutagenicity and aryl hydrocarbon receptor activity, than their corresponding parent PAHs. Investigation of the sources and environmental behavior of ClPAHs is of great importance in the assessment of human health risks.

  3. Sorption- and diffusion-associated isotope effects for chlorinated and non chlorinated aromatic hydrocarbons in a sediment pore water diffusion sampler

    Science.gov (United States)

    Passeport, E.; Chu, K.; Lacrampe Couloume, G.; Landis, R.; Lutz, E. J.; Mack, E. E.; West, K.; Sherwood Lollar, B.

    2013-12-01

    Compound Specific Isotope Analysis (CSIA) has gained prominence for evaluation of microbial and abiotic degradation processes governing the fate of organic contaminants in groundwater. At the sediment pore water interface, in wetland or river bottom sediments, variations in oxidation-reduction conditions can affect reaction mechanisms and hence the contaminant mass flux discharged to surface waters. Carbon isotope fractionation has been shown to be an important tool in identifying the effects of degradation and differentiating between different degradation pathways. To date, while passive diffusion samplers (commonly called 'peepers') have provided a powerful tool for high spatial resolution sampling for dissolved VOC across the sediment water interface, peepers' compatibility with CSIA has never been evaluated. The operating principle of peepers involves compound diffusion from the sediment pore water to the peeper chambers via a membrane. In this study, we evaluated the isotope effects of diffusion through, and possible adsorption to a polysulfone membrane for priority groundwater contaminants including chlorinated and non-chlorinated aromatic hydrocarbons. Chlorinated benzenes tend to accumulate in the food web and therefore represent a significant threat to water resources. This is due to their larger sorption coefficients (Koc) and higher hydrophobicity properties (logKow) compared to other commonly-studied compounds (e.g., chlorinated ethenes). Application of CSIA to BTEX and chlorinated ethenes has demonstrated that non-degradative processes (e.g., sorption, volatilization, diffusion) typically result in smaller carbon isotope fractionation compared to degradative processes that involve breaking bonds. The large sorption properties of chlorinated benzenes preclude a direct extrapolation to these compounds of existing data on sorption-associated isotope effects obtained on other compounds. To date, similar studies have not been done for chlorinated aromatics

  4. Degradation of Chlorinated Aromatic Compounds in UASB Reactors

    DEFF Research Database (Denmark)

    Christiansen, Nina; Hendriksen, Hanne Vang; Järvinen, Kimmo T.;

    1995-01-01

    Data on anaerobic degradation of chloroaromatic compounds in Upflow Anaerobic Sludge Blanket Reactors (UASB-reactor) are presented and compared. Special attention is given to the metabolic pathways for degradation of chlorinated phenols by granular sludge. Results indicate that PCP can be degraded...

  5. Potential of non-ligninolytic fungi in bioremediation of chlorinated and polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Marco-Urrea, Ernest; García-Romera, Inmaculada; Aranda, Elisabet

    2015-12-25

    In previous decades, white-rot fungi as bioremediation agents have been the subjects of scientific research due to the potential use of their unspecific oxidative enzymes. However, some non-white-rot fungi, mainly belonging to the Ascomycota and Zygomycota phylum, have demonstrated their potential in the enzymatic transformation of environmental pollutants, thus overcoming some of the limitations observed in white-rot fungi with respect to growth in neutral pH, resistance to adverse conditions and the capacity to surpass autochthonous microorganisms. Despite their presence in so many soil and water environments, little information exists on the enzymatic mechanisms and degradation pathways involved in the transformation of hydrocarbons by these fungi. This review describes the bioremediation potential of non-ligninolytic fungi with respect to chlorinated hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) and also shows known conversion pathways and the prospects for future research.

  6. Influencing factors and degradation products of antipyrine chlorination in water with free chlorine

    Institute of Scientific and Technical Information of China (English)

    Meiquan Cai; Liqiu Zhang; Fei Qi; Li Feng

    2013-01-01

    Owing to its low cost,free chlorine is one of the most common disinfectants for wastewater and drinking water treatment.However,the formation of disinfection byproducts has been found to occur after free chlorine disinfection in recent decades.Antipyrine (ANT),an anti-inflammatory analgesic,has been frequently detected in the aquatic environment.In this work.the removal efficiency of ANT by free chlorine oxidation in ultrapure water was investigated with batch experiments.The influencing factors on the removal of ANT were explored at initial concentrations of ANT from 0.04 to 0.64 mg/L,free chlorine dosage from 0.30 to 1.31 mg/L,and pH from 1.5 to 9.0.The main degradation products were identified by solid phase extraction-gas chromatography-mass spectrometry.The results showed that ANT reacted rapidly with free chlorine in ultrapure water systems and up to 90.6% removal efficiency of ANT was achieved after 25 sec (initial free chlorine 1 mg/L,ANT 0.5 mg/L,pH 7.0).Higher oxidant dosage,lower ANT initial concentration and low pH favor the ANT removal.The main degradation product in ANT chlorination was a monochlorine substitution product (4-chloro-l,2-dihydro1,5-dimethyl-2-phenyl-3H-pyrazol-3-one),which can be further chlorinated by free chlorine.In addition,the total organic carbon result indicated that ANT is difficult to be mineralized using chlorine.

  7. Influencing factors and degradation products of antipyrine chlorination in water with free chlorine.

    Science.gov (United States)

    Cai, Meiquan; Zhang, Liqiu; Qi, Fei; Feng, Li

    2013-01-01

    Owing to its low cost, free chlorine is one of the most common disinfectants for wastewater and drinking water treatment. However, the formation of disinfection byproducts has been found to occur after free chlorine disinfection in recent decades. Antipyrine (ANT), an anti-inflammatory analgesic, has been frequently detected in the aquatic environment. In this work, the removal efficiency of ANT by free chlorine oxidation in ultrapure water was investigated with batch experiments. The influencing factors on the removal of ANT were explored at initial concentrations of ANT from 0.04 to 0.64 mg/L, free chlorine dosage from 0.30 to 1.31 mg/L, and pH from 1.5 to 9.0. The main degradation products were identified by solid phase extraction-gas chromatography-mass spectrometry. The results showed that ANT reacted rapidly with free chlorine in ultrapure water systems and up to 90.6% removal efficiency of ANT was achieved after 25 sec (initial free chlorine 1 mg/L, ANT 0.5 mg/L, pH 7.0). Higher oxidant dosage, lower ANT initial concentration and low pH favor the ANT removal. The main degradation product in ANT chlorination was a monochlorine substitution product (4-chloro-1,2-dihydro-1,5-dimethyl-2-phenyl-3H-pyrazol-3-one), which can be further chlorinated by free chlorine. In addition, the total organic carbon result indicated that ANT is difficult to be mineralized using chlorine.

  8. Anaerobic biotransformation of chlorinated aliphatic hydrocarbons: Ugly duckling to beautiful swan

    Energy Technology Data Exchange (ETDEWEB)

    Parkin, G.F.

    1999-10-01

    For many years anaerobic biological processes were reputed to be more sensitive than aerobic processes to toxic substances such as chlorinated aliphatic hydrocarbons (CAH) and thus a poor choice for treating water containing these compounds. This was especially true for water containing perchloroethylene (PCE) or trichloroethylene (TCE) because vinyl chloride, a human carcinogen, is produced when these two compounds are degraded anaerobically. Aerobic treatment with organisms containing oxygenase enzyme systems, which could fortuitously degrade a wide variety of chlorinated aliphatics (but not PCE), was favored. Recently, however, several enrichments and organisms have been isolated that will convert PCE and TCE into ethene and ethane, as shown by field data. Because of this evidence, anaerobic processes are now considered a significant alternative treatment for CAH contamination. Recent work at the University of Iowa, Iowa City, has focused on the effect of mixtures of CAHs on biotransformation of individual organic compounds and the potential for a combined methanogen-iron (Fe(0)) system to improve CAH bioremediation. At the concentration ranges tested, the presence of a mixture of CAHs seems to decrease rate of transformation of individual organics. However, there are important exceptions; in some cases a mixture of CAHs seems to facilitate transformation of an individual organic compound. Combination of an active methanogenic population with Fe(0) increases the rate and extent of transformation of carbon tetrachloride and chloroform. Results with PCE and 1,1,1-trichloroethane are less clear.

  9. Solidification of sediment contaminated with volatile chlorinated hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, E.J. [Anchor QEA LLC, Portland, OR (United States)

    2010-07-01

    A series of bench-scale treatability tests were used to evaluate the effectiveness of various solidification reagents in treating sediments contaminated with high concentrations of chlorinated hydrocarbons. The effectiveness of Portland cement, cement kiln dust, lime kiln dust, fly ash, and a combination of silica and lime were was assessed relative to their ability to reduce the leaching of contaminants, increase the strength of the contaminated sediment, and reduce the hydraulic conductivity of the sediments. The aim of the study was to develop a design for treating sediments in a stagnant water body located on the grounds of an industrial facility. The sediments were predominantly fine-grained and high in organic content. Preliminary tests identified Portland cement and the silica and lime mixture as achieving the desired strength and resistance to leaching. The solidification reagents were used to solidify more than 11,000 cubic yards of sediment with a mixture of 2 fly ashes. The full-scale solidification project surpassed the required standards for strength and permeability. 10 refs., 4 tabs., 3 figs.

  10. Natural attenuation of chlorinated hydrocarbons in a freshwater wetland

    Science.gov (United States)

    Lora, Michelle M.; Olsen, Lisa D.; Smith, Barrett L.

    1997-01-01

    Natural attenuation of chlorinated volatile organic compounds (VOC's) occurs as ground water discharges from a sand aquifer to a freshwater wetland at Aberdeen Proving Ground, Md. Field and laboratory results indicate that biotransformation in the anaerobic wetland sediments is an important attenuation process. Relatively high concentrations of the parent compounds trichloroethylene (TCE) and 1,1,2,2-tetrachloroethane (PCA) and low or undetectable concentrations of daughter products were measured in the aquifer. In contrast, relatively high concentrations of the daughter products cis- and trans-1,2-dichloroethylene (12DCE); vinyl chloride (VC); 1,1,2-trichloroethane (112TCA); and 1,2-dichloroethane (12DCA) were measured in ground water in the wetland sediments, although total VOC concentrations decreased upward from about 1 mu mol/L (micromoles per liter) at the base of the wetland sediments to less than 0.2 near the surface. Microcosm experiments showed that 12DCE and VC are produced from anaerobic degradation of both TCE and PCA; PCA degradation also produced 112TCA and 12DCA.

  11. HYDROCARBON-DEGRADING BACTERIA AND SURFACTANT ACTIVITY

    Energy Technology Data Exchange (ETDEWEB)

    Brigmon, R; Topher Berry, T; Grazyna A. Plaza, G; jacek Wypych, j

    2006-08-15

    Fate of benzene ethylbenzene toluene xylenes (BTEX) compounds through biodegradation was investigated using two different bacteria, Ralstonia picketti (BP-20) and Alcaligenes piechaudii (CZOR L-1B). These bacteria were isolated from extremely polluted petroleum hydrocarbon contaminated soils. PCR and Fatty Acid Methyl Ester (FAME) were used to identify the isolates. Biodegradation was measured using each organism individually and in combination. Both bacteria were shown to degrade each of the BTEX compounds. Alcaligenes piechaudii biodegraded BTEXs more efficiently while mixed with BP-20 and individually. Biosurfactant production was observed by culture techniques. In addition 3-hydroxy fatty acids, important in biosurfactant production, was observed by FAME analysis. In the all experiments toluene and m+p- xylenes were better growth substrates for both bacteria than the other BTEX compounds. In addition, the test results indicate that the bacteria could contribute to bioremediation of aromatic hydrocarbons (BTEX) pollution increase biodegradation through the action by biosurfactants.

  12. Synergistic effect between UV and chlorine (UV/chlorine) on the degradation of carbamazepine: Influence factors and radical species.

    Science.gov (United States)

    Wang, Wen-Long; Wu, Qian-Yuan; Huang, Nan; Wang, Ting; Hu, Hong-Ying

    2016-07-01

    For successful wastewater reclamation, advanced oxidation processes have attracted attention for elimination of emerging contaminants. In this study, the synergistic treatment with UV irradiation and chlorine (UV/chlorine) was used to degrade carbamazepine (CBZ). Neither UV irradiation alone nor chlorination alone could efficiently degraded CBZ. UV/chlorine oxidation showed a significant synergistic effect on CBZ degradation through generation of radical species (OH and Cl), and this process could be well depicted by pseudo first order kinetic. The degradation rate constants (kobs,CBZ) of CBZ increased linearly with increasing UV irradiance and chlorine dosage. The degradation of CBZ by UV/chlorine in acidic solutions was more efficient than that in basic solutions mainly due to the effect of pH on the dissociation of HOCl and OCl(-) and then on the quantum yields and radical species quenching of UV/chlorine. When pH was increased from 5.5 to 9.5, the rate constants of degradation of CBZ by OH decreased from 0.65 to 0.14 min(-1) and that by Cl decreased from 0.40 to 0.11 min(-1). The rate constant for the reaction between Cl and CBZ was 5.6 ± 1.6 × 10(10) M(-1) s(-1). Anions of HCO3(-) (1-50 mM) showed moderate inhibition of CBZ degradation by UV/chlorine, while Cl(-) did not. UV/chlorine could efficiently degrade CBZ in wastewater treatment plant effluent, although the degradation was inhibited by about 30% compared with that in ultrapure water with chlorine dosage of 0.14-0.56 mM. Nine main oxidation products of the CBZ degradation by UV/chlorine were identified using the HPLC-QToF MS/MS. Initial oxidation products arose from hydroxylation, carboxylation and hydrogen atom abstraction of CBZ by OH and Cl, and were then further oxidized to generate acylamino cleavage and decarboxylation products of acridine and acridione. PMID:27105033

  13. Formation of phosgene during welding activities in an atmosphere containing chlorinated hydrocarbons.

    Science.gov (United States)

    Nieuwenhuizen, M S; Groeneveld, F R

    2000-01-01

    The formation of phosgene During welding activities in an atmosphere containing chlorinated hydrocarbons was investigated. Four different chlorinated hydrocarbons were studied under laboratory conditions. Results are presented as time-averaged phosgene concentration in a total volume of 250 L of air being purged through a 52-L reaction vessel during 20 min. It was found that the formation of phosgene was in the order dichloromethane smoke particles and because of possible nonhomogeneous dispersion of phosgene around the workers. In the case of dichloromethane and carbon tetrachloride the short-term maximum allowable concentration (MAC) of phosgene was not attained at the respective MAC values of the chlorinated hydrocarbons themselves. In the case of trichloroethylene and Freon-22, however, the short-term MAC-value of phosgene was attained even when the concentration was still much below the respective MAC-values.

  14. Heavy metal and chlorinated hydrocarbon residues in California sea loins (Zalophus californianus californianus)

    Energy Technology Data Exchange (ETDEWEB)

    Buhler, D.R.; Claeys, R.R.; Mate, B.R.

    1975-12-01

    Samples of various tissues and organs from healthy California sea lions (Zalophus californianus californianus) and sick animals (apparently with leptospirosis) collected along the central Oregon coast in 1970, 1971, and 1973 were analyzed for total mercury, methylmercury, cadmium, and chlorinated hydrocarbons. Maximum mercury concentrations of 74 to 170 ppM occurred in sea lion liver, but only 1.6 to 3.7 percent of this was present as methylmercury. Cadmium was concentrated primarily in the kidney which contained 7.2 to 12.0 ppM of the metal. Chlorinated hydrocarbon residues in sea lion fat ranged between 253 to 475 ppM DDE, and 21.2 and 34.1 ppM PCB. Although mercury, cadmium, and chlorinated hydrocarbon residues in some of the sick sea lions were significantly higher than those present in healthy animals, it is not possible to relate these differences to the onset of leptospirosis.

  15. Degradation mechanisms of geosmin and 2-MIB during UV photolysis and UV/chlorine reactions.

    Science.gov (United States)

    Kim, Tae-Kyoung; Moon, Bo-Ram; Kim, Taeyeon; Kim, Moon-Kyung; Zoh, Kyung-Duk

    2016-11-01

    We conducted chlorination, UV photolysis, and UV/chlorin reactions to investigate the intermediate formation and degradation mechanisms of geosmin and 2-methylisoborneol (2-MIB) in water. Chlorination hardly removed geosmin and 2-MIB, while the UV/chlorine reaction at 254 nm completely removed geosmin and 2-MIB within 40 min and 1 h, respectively, with lesser removals of both compounds during UV photolysis. The kinetics during both UV photolysis and UV/chlorine reactions followed a pseudo first-order reaction. Chloroform was found as a chlorinated intermediate during the UV/chlorine reaction of both geosmin and 2-MIB. The pH affected both the degradation and chloroform production during the UV/chlorine reaction. The open ring and dehydration intermediates identified during UV/chlorine reactions were 1,4-dimethyl-adamantane, and 1,3-dimethyl-adamantane from geosmin, 2-methylenebornane, and 2-methyl-2-bornene from 2-MIB, respectively. Additionally, 2-methyl-3-pentanol, 2,4-dimethyl-1-heptene, 4-methyl-2-heptanone, and 1,1-dichloro-2,4-dimethyl-1-heptane were newly identified intermediates from UV/chlorine reactions of both geosmin and 2-MIB. These intermediates were degraded as the reaction progressed. We proposed possible degradation pathways during the UV photolysis and UV/chlorine reactions of both compounds using the identified intermediates.

  16. In situ bioremediation of petroleum hydrocarbons and chlorinated hydrocarbons: Three case studies

    International Nuclear Information System (INIS)

    In situ biodegradation of organic contaminants is one of the most cost-effective means of site remediation. This method has proven successful in soils, ground water, and slurries. Bacteria capable of degrading organic contaminants within an aquifer include many species from a wide spectrum of genera, e.g. Pseudomonas, Corynebacterium, Bacillus, etc. In most cases, a mixture of bacterial strains is required to completely oxidize a complex organic contaminant. Each strain of an organism may target a specific compound, working together with other organisms to ultimately degrade each intermediate until complete degradation, also known as mineralization, occurs. One or more of the following mechanisms are utilized by bacteria for organic chemical degradation: (1) aerobic, (2) anaerobic, and (3) co-metabolic. During aerobic oxidation of organic chemicals, bacteria utilize the pollutant as an electron and hydrogen source and oxygen acts as the electron and hydrogen acceptor, resulting in water. As the bacterial enzymes cleave the compound, oxidized products are produced along with energy for the reaction to proceed. This is the most rapid and widely utilized mechanism. Dehalogenation occurs under aerobic, or perhaps more often, under anoxic conditions. This process occurs in the presence of alternate electron acceptors and replaces chlorine with hydrogen. The mechanism of co-metabolism can be aerobic or anaerobic, but is more often aerobic. This process requires a separate energy source for the bacterial cell because the pollutant is not utilized as an energy source. The role of bioremediation in site remediation is demonstrated below by three case studies: (1) a refinery, (2) a municipal landfill and (3) a pesticide formulation plant

  17. Application of Pseudomonas sp. strain DCA1 for the removal of chlorinated hydrocarbons

    NARCIS (Netherlands)

    Hage, J.C.

    2004-01-01

    The large-scale application of chlorinated aliphatic hydrocarbons (CAHs) has resulted in many cases of groundwater contamination. Contaminated groundwater can be remediated by pump-and-treat: the groundwater is pumped to the surface and treated. The groundwater can be treated in bioreactors, in whic

  18. Microbial diversity in a hydrocarbon- and chlorinated-solvent- contaminated aquifer undergoing intrinsic bioremediation

    Science.gov (United States)

    Dojka, M.A.; Hugenholtz, P.; Haack, S.K.; Pace, N.R.

    1998-01-01

    A culture-independent molecular phylogenetic approach was used to survey constituents of microbial communities associated with an aquifer contaminated with hydrocarbons (mainly jet fuel) and chlorinated solvents undergoing intrinsic bioremediation. Samples were obtained from three redox zones: methanogenic, methanogenic-sulfate reducing, and iron or sulfate reducing. Small-subunit rRNA genes were amplified directly from aquifer material DNA by PCR with universally conserved or Bacteria- or Archaea-specific primers and were cloned. A total of 812 clones were screened by restriction fragment length polymorphisms (RFLP), approximately 50% of which were unique. All RFLP types that occurred more than once in the libraries, as well as many of the unique types, were sequenced. A total of 104 (94 bacterial and 10 archaeal) sequence types were determined. Of the 94 bacterial sequence types, 10 have no phylogenetic association with known taxonomic divisions and are phylogenetically grouped in six novel division level groups (candidate divisions WS1 to WS6); 21 belong to four recently described candidate divisions with no cultivated representatives (OPS, OP8, OP10, and OP11); and 63 are phylogenetically associated with 10 well-recognized divisions. The physiology of two particularly abundant sequence types obtained from the methanogenic zone could be inferred from their phylogenetic association with groups of microorganisms with a consistent phenotype. One of these sequence types is associated with the genus Syntrophus; Syntrophus spp. produce energy from the anaerobic oxidation of organic acids, with the production of acetate and hydrogen. The organism represented by the other sequence type is closely related to Methanosaeta spp., which are known to be capable of energy generation only through aceticlastic methanogenesis. We hypothesize, therefore, that the terminal step of hydrocarbon degradation in the methanogenic zone of the aquifer is aceticlastic methanogenesis and

  19. Thermal degradation of sucralose: a combination of analytical methods to determine stability and chlorinated byproducts

    Science.gov (United States)

    de Oliveira, Diogo N.; de Menezes, Maico; Catharino, Rodrigo R.

    2015-04-01

    In the late years, much attention has been brought to the scientific community regarding the safety of sucralose and its industrial applications. Although it is the most used artificial sweetener in foods and pharmaceuticals, many questions still arise on its potential to form chlorinated byproducts in high temperatures, as demonstrated by several recent studies. In the present contribution, we use a combination of differential scanning calorimetry and thermogravimetric analysis coupled with infrared spectroscopy (DSC/TGA/IR), Hot-stage microscopy (HSM) and high-resolution mass spectrometry (HRMS) on samples submitted to water bath at mild temperatures to evaluate a broad spectrum of hazardous compounds formed in the degradation of this product. TGA/IR has revealed that there is effective decomposition in form of CO2 along with the formation of hydrogen chloride and other minor compounds. HSM results have provided accurate information, where the melting of the crystals was observed, followed by decomposition. Chlorinated derivatives, including polychlorinated aromatic hydrocarbons (PCAHs) were also confirmed by HRMS. These findings not only corroborate the suspected instability of sucralose to high temperatures, but also indicate that even exposed to mild conditions the formation of hazardous polychlorinated compounds is observed.

  20. Metabolism of volatile chlorinated aliphatic hydrocarbons by Pseudomonas fluorescens.

    OpenAIRE

    Vandenbergh, P A; Kunka, B S

    1988-01-01

    A Pseudomonas fluorescens strain designated PFL12 was isolated from soil and water that were contaminated with various chloroaliphatic hydrocarbons. The isolate was able to metabolize 1,2-dichloroethane, 1,1,2-trichloroethane, 1,2-dichloropropane, 2,2-dichloropropane, and trichloroethylene.

  1. Degradation of microcystin-RR in water by chlorine dioxide

    Institute of Scientific and Technical Information of China (English)

    JI Ying; HUANG Jun-li; FU Jiao; WU Ming-song; CUI Chong-wei

    2008-01-01

    Due to the potent hepatotoxicity and tumor-promoting activity of microcystins, a successful removal of these toxins during drinking water treatment processes is of increasing concern. The oxidation kinetics of MC-RR by chlorine dioxide (C1O2)was studied with HPLC and characterization of the reacdon products was performed with UV-spectrometry, TOC and LC-MS. Our experimental results show that the oxidation process is a second order overall and a first order with respect to C1O2 and MC-RR.The activation energy of MC-RR degradation by C1O2 is 53.07 kJ/mol. The rate constant k of the action can be increased by increasing temperature and decreasing pH value and ranged from 6. 11x102 L/(mol.min) to 5.29x 102 L/(mol-min) at pH from 3.44 to 10.41 at 10 ℃. Reaction products were determined to be organic and volatile, because they could be almost removed from aqueous solution by heating for 15 min at 60 ℃. In addition, the main oxidation products have m/z values of 1072 and are identified as dihydroxy isomers of MC-RR.

  2. Biodegradation of chlorinated hydrocarbons in a vapor phase reactor

    International Nuclear Information System (INIS)

    A bench scale gas lift loop reactor was constructed to evaluate the feasibility of trichloroethylene (TCE) degradative microorganisms being used to treat TCE contaminated air. Two different microorganisms were used as biocatalysts in this reactor. After proper operating conditions were established for use of this reactor/biocatalyst combination, both microorganisms could degrade 95% of inlet TCE at air flow rates of up to 3% of the total reactor volume per minute. TCE concentrations of between 300 μg/L (60ppmv) and 3000 μg/L (600 ppmv) were degraded with 95% or better efficiency. Preliminary economic evaluations suggest that bioremediation may be the low cost alternative for treating certain TCE contaminated air streams and field trials of a scaled-up reactor system based on this technology are currently underway

  3. Microbial Degradation of Polycyclic Aromatic Hydrocarbons and Characterization of Bacteria

    Science.gov (United States)

    Tikilili, P. V.; Chirwa, E. M. N.

    2010-01-01

    Biodegradation of polycyclic aromatic hydrocarbons was studied. Naphthalene was used as a model compound to represent these compounds. Low initial concentrations of naphthalene in a range of 30-60 mg/L were completely degraded after incubation for 15 hrs by consortia from a landfill soil while consortia from minewater took more that 29 hrs to reach complete degradation.

  4. Degradation of atrazine by UV/chlorine: Efficiency, influencing factors, and products.

    Science.gov (United States)

    Kong, Xiujuan; Jiang, Jin; Ma, Jun; Yang, Yi; Liu, Weili; Liu, Yulei

    2016-03-01

    In this work, the degradation of atrazine by the combination of UV and chlorine (UV/chlorine) due to the formation of radicals during chlorine photolysis was systematically investigated in terms of efficiency, factors that influence the degradation kinetics, as well as oxidation products. It was found that the degradation efficiency of atrazine was enhanced by UV/chlorine compared to UV or chlorine alone. The degradation efficiency of atrazine was favorable at a lower pH, but was inhibited in the presence of natural organic matters. Meanwhile, the initial chlorine dosage, alkalinity, and chloride barely influenced the degradation efficiency under neutral pH conditions. The degradation of atrazine by UV/chlorine was inhibited in real waters (i.e., surface water and ground water) compared to in deionized water but was still more effective than UV alone. The oxidation products of atrazine resulting from de-alkylation, dechlorination-hydroxylation, alkylic-hydroxylation, alkylic-oxidation, alkylic-hydroxylation-dehydration, deamination-hydroxylation, and dechlorination-hydrogenation in UV/chlorine process were detected, which were slightly different from those formed in UV/H2O2 (commonly used UV-based advanced oxidation process). Particularly, the yields of three primary transformation products (desethyl-atrazine (DEA), desisopropyl-atrazine (DIA), and desethyl-desisopropyl-atrazine (DEIA)) were comparatively quantified in these two processes. The different trend of them formed in UV/chlorine system (DEA:DIA≈4) compared to that formed in UV/H2O2 system (DEA:DIA≈1) could be ascribed to the different reaction reactivities and mechanisms between HO• and Cl• with atrazine.

  5. Kinetics and pathways of ibuprofen degradation by the UV/chlorine advanced oxidation process.

    Science.gov (United States)

    Xiang, Yingying; Fang, Jingyun; Shang, Chii

    2016-03-01

    The UV/chlorine advanced oxidation process (AOP), which forms reactive species such as hydroxyl radicals (HO) and reactive chlorine species (RCS) such as chlorine atoms (Cl) and Cl2(-), is being considered as an alternative to the UV/H2O2 AOP for the degradation of emerging contaminants. This study investigated the kinetics and pathways of the degradation of a recalcitrant pharmaceutical and personal care product (PPCP)-ibuprofen (IBP)-by the UV/chlorine AOP. The degradation of IBP followed the pseudo first-order kinetics. The first-order rate constant was 3.3 times higher in the UV/chlorine AOP than in the UV/H2O2 AOP for a given chemical molar dosage at pH 6. The first-order rate constant decreased from 3.1 × 10(-3) s(-1) to 5.5 × 10(-4) s(-1) with increasing pH from 6 to 9. Both HO and RCS contributed to the degradation, and the contribution of RCS increased from 22% to 30% with increasing pH from 6 to 9. The degradation was initiated by HO-induced hydroxylation and Cl-induced chlorine substitution, and sustained through decarboxylation, demethylation, chlorination and ring cleavage to form more stable products. Significant amounts of chlorinated intermediates/byproducts were formed from the UV/chlorine AOP, and four chlorinated products were newly identified. The yield of total organic chlorine (TOCl) was 31.6 μM after 90% degradation of 50 μM IBP under the experimental conditions. The known disinfection by-products (DBPs) comprised 17.4% of the TOCl. The effects of water matrix in filtered drinking water on the degradation were not significant, demonstrating the practicality of the UV/chlorine AOP for the control of some refractory PPCPs. However, the toxicity of the chlorinated products should be further assessed.

  6. Degradation of anthracene, pyrene and benzo[a]anthracene in aqueous solution by chlorine dioxide

    Institute of Scientific and Technical Information of China (English)

    LIU; Jinquan; HUANG; Junli; SU; Liqiang; CAO; Xiangyu; JI; Ying

    2006-01-01

    Polycyclic aromatic hydrocarbons (PAHs) constitute an important group of micropollutants, which are known to be mutagenic, carcinogenic and/or co-carcinogenic and relatively persistent in the environment. The effects of chlorine dioxide (ClO2) on the degradation of anthracene (ANTH), pyrene (PYR) and benzo[a]anthracene (BaA) in aqueous solution were investigated using high performance liquid chromatography (HPLC). In preliminary experiments, it was observed that ClO2 could remove these three PAHs effectively within a short time. Several factors including reaction time, the concentration of ClO2 and pH of the reaction mixture influencing the degradation ratio of PAHs have been studied by batch experiments. The results showed that the degradation ratio of PAHs was affected by reaction time and the concentration of ClO2 instead of pH. The degradation ratio of ANTH, PYR and BaA could reach their maximum as approximately 99.0%, 67.5% and 89.5%, respectively, under the condition as follows: reaction time 30, 60 and 120 min, the concentration of ClO2 0.1, 0.4 and 0.5 mmol·L-1, and pH 7.2. ANTH was selected as the representative to study the reaction mechanism with ClO2. The oxidation products formed in the reaction of ANTH with ClO2 were tentatively identified by gas chromatography-mass spectrometry (GC-MS), and the results showed that the main product was 9, 10-anthraquinone, which could be biodegraded more easily and quickly than ANTH. Through analyzing the reaction properties of ANTH and ClO2, the possible pathway for the ANTH-ClO2 reaction was proposed based on the theory of single electron transfer (SET).

  7. Degradation of hydrocarbons under methanogenic conditions in different geosystems

    Science.gov (United States)

    Straaten, Nontje; Jiménez García, Núria; Richnow, Hans-Hermann; Krueger, Martin

    2014-05-01

    With increasing energy demand the search for new resources is becoming increasingly important for the future energy supply. Therefore the knowledge about fossil fuels like oil or natural gas and their extraction should be expanded. Biodegraded oil is found in many reservoirs worldwide. Consequently, it is very important to get insight in the microbial communities and metabolic processes involved in hydrocarbon degradation. Due to the lack of alternative electron acceptors in hydrocarbon-rich geosystems, degradation often takes place under methanogenic conditions. The aim of the present study is to identify the microorganisms and mechanisms involved in the degradation of complex hydrocarbons, like BTEX and polycyclic aromatic hydrocarbons, using culture dependent and independent techniques. For this purpose enrichment cultures from marine sediments, shales, coal and oil reservoirs are monitored for their capability to degrade alkanes and aromatic compounds. Moreover the environmental samples of these different geosystems analysed for evidence for the in situ occurrence of methanogenic oil degradation. The gas geochemical data provided in several cases hints for a recent biological origin of the methane present. First results of the microbial community analysis showed in environmental samples and enrichment cultures the existence of Bacteria known to degrade hydrocarbons. Also a diverse community of methanogenic Archaea could be found in the clone libraries. Additionally, in oil and coal reservoir samples the degradation of model hydrocarbons, e.g. methylnaphthalene, hexadecane and BTEX, to CH4 was confirmed by 13C-labeling. To explore the mechanisms involved in biodegradation, the enrichments as well as the original environmental samples are further analysed for the presence of respective functional genes.

  8. Degradation of polynuclear aromatic hydrocarbons by two strains of Pseudomonas.

    Science.gov (United States)

    Nwinyi, Obinna C; Ajayi, Oluseyi O; Amund, Olukayode O

    2016-01-01

    The goal of this investigation was to isolate competent polynuclear aromatic hydrocarbons degraders that can utilize polynuclear aromatic hydrocarbons of former industrial sites at McDoel Switchyard in Bloomington, Indiana. Using conventional enrichment method based on soil slurry, we isolated, screened and purified two bacterial species strains PB1 and PB2. Applying the ribotyping technique using the 16S rRNA gene analysis, the strains were assigned to the genus Pseudomonas (Pseudomonas plecoglossicida strain PB1 and Pseudomonas sp. PB2). Both isolates showed promising metabolic capacity on pyrene sprayed MS agar plates during the preliminary investigations. Using time course studies in the liquid cultures at calculated concentrations 123, 64, 97 and 94ppm for naphthalene, chrysene, fluroanthene and pyrene, P. plecoglossicida strain PB1 and Pseudomonas sp. PB2 showed partial utilization of the polynuclear aromatic hydrocarbons. Naphthalene was degraded between 26% and 40%, chrysene 14% and 16%, fluroanthene 5% and 7%; pyrene 8% and 13% by P. plecoglossicida strain PB1 and Pseudomonas sp. PB2 respectively. Based on their growth profile, we developed a model R(2)=1 to predict the degradation rate of slow polynuclear aromatic hydrocarbon-degraders where all the necessary parameters are constant. From this investigation, we confirm that the former industrial site soil microbial communities may be explored for the biorestoration of the industrial site. PMID:27245129

  9. Microbial degradation of crude oil hydrocarbons on organoclay minerals.

    Science.gov (United States)

    Ugochukwu, Uzochukwu C; Manning, David A C; Fialips, Claire I

    2014-11-01

    The role of organoclays in hydrocarbon removal during biodegradation was investigated in aqueous clay/oil microcosm experiments with a hydrocarbon degrading microorganism community. The clays used for this study were Na-montmorillonite and saponite. These two clays were treated with didecyldimethylammonium bromide to produce organoclays which were used in this study. The study indicated that clays with high cation exchange capacity (CEC) such as Na-montmorillonite produced an organomontmorillonite that was inhibitory to biodegradation of the crude oil hydrocarbons. Extensive hydrophobic interaction between the organic phase of the organoclay and the crude oil hydrocarbons is suggested to render the hydrocarbons unavailable for biodegradation. However, untreated Na-montmorillonite was stimulatory to biodegradation of the hydrocarbons and is believed to have done so because of its high surface area for the accumulation of microbes and nutrients making it easy for the microbes to access the nutrients. This study indicates that unlike unmodified montmorillonites, organomontmorillonite may not serve any useful purpose in the bioremediation of crude oil spill sites where hydrocarbon removal by biodegradation is desired within a rapid time period. PMID:24956464

  10. [Degradation Kinetics and Formation of Disinfection By-products During Linuron Chlorination in Drinking Water].

    Science.gov (United States)

    Ling, Xiao; Hu, Chen-yan; Cheng, Ming; Gu, Jian

    2015-05-01

    Chlorination degradation of linuron was studied using the common disinfectant sodium hypochlorite, the effects of chlorine dosage, pH value, bromine ion concentrationand temperature were systematically investigated, and the formation characteristics of disinfection by-products (DBPs) during the chlorination reaction was analyzed. The results showed that the chlorination degradation kinetics of linuron by sodium hypochlorite could be well described by the second-order kinetic model. Moreover, pH values had a great impact on the degradation reaction, and the rate constant reached the maximum level at pH 7, and the base elementary reaction rate constants of HOCl and OCl- with linuron were 4.84 x 10(2) L · (mol · h)(-1) and 3.80 x 10(2) L · (mol · h)(-1), respectively. The reaction rate decreased with the addition of bromide ion and increased with increasing temperature. Furthermore, many kinds of disinfection by- products were produced during the chlorination degradation of linuron, including CF, DCAN, TCNM and halogen acetone. Under conditions of different solution pH and different bromide ion concentrations, there would be significant difference in the types and concentrations of disinfection by-products.

  11. Natural attenuation of chlorinated-hydrocarbon contamination at Fort Wainwright, Alaska; a hydrogeochemical and microbiological investigation workplan

    Science.gov (United States)

    McCarthy, Kathleen A.; Lilly, Michael R.; Braddock, Joan F.; Hinzman, Larry D.

    1998-01-01

    Natural attenuation processes include biological degradation, by which microorganisms break down contaminants into simpler product compounds; adsorption of contaminants to soil particles, which decreases the mass of contaminants dissolved in ground water; and dispersion, which decreases dissolved contaminant concentrations through dilution. The primary objectives of this study are to (1) assess the degree to which such natural processes are attenuating chlorinated-hydrocarbon contamination in ground water, and (2) evaluate the effects of ground-water/surface-water interactions on natural-attenuation processes in the area of the former East and West Quartermasters Fueling Systems for Fort Wainwright, Alaska. The study will include investigations of the hydrologic, geochemical, and microbiological processes occurring at this site that influence the transport and fate of chlorinated hydrocarbons in ground water. To accomplish these objectives, a data-collection program has been initiated that includes measurements of water-table elevations and the stage of the Chena River; measurements of vertical temperature profiles within the subsurface; characterization of moisture distribution and movement in the unsaturated zone; collection of ground-water samples for determination of both organic and inorganic chemical constituents; and collection of ground-water samples for enumeration of microorganisms and determination of their potential to mineralize contaminants. We will use results from the data-collection program described above to refine our conceptual model of hydrology and contaminant attenuation at this site. Measurements of water-table elevations and river stage will help us to understand the magnitude and direction of ground-water flow and how changes in the stage of the Chena River affect ground-water flow. Because ambient ground water and surface water typically have different temperature characteristics, temperature monitoring will likely provide further insight

  12. Dechlorination progress of chlorinated organic pollutants degraded by use of ionizing radiation in aqueous solutions

    International Nuclear Information System (INIS)

    Kinetics and mechanisms of dechlorination of chlorinated organic pollutants induced by ionizing radiation were described in this article. The progress on the dechlorination of chlorophenols, polychlorinated biphenyl, trichloroethylene, and perchloroethylene involved in radiolysis was also reviewed. In oxidative condition, hydroxyl radical (·OH) would attack chlorophenol to form ·OH-adducts, which could be dechlorinated gradually. However, chlorophenol can be directly reduced by hydrated electron (eaq-) to release Cl-. It was found that radiolytic degradation of polychlorinated biphenyls in organic solvent would release chlorine atoms gradually by chain reactions and the final products were Cl- and biphenyl. Trichloroethylene and tetrachloroethylene mainly reacted with ·OH with the final products of CO2, HCOOH and HCI. As conclusion, the reductive dechlorination of chlorinated organic pollutants possesses advantages of high degradation efficiency, simple products and relatively low radiation dose compared with the oxidation methods. (authors)

  13. Simulation of ground-water flow and transport of chlorinated hydrocarbons at Graces Quarters, Aberdeen Proving Ground, Maryland

    Science.gov (United States)

    Tenbus, Frederick J.; Fleck, William B.

    2001-01-01

    Military activity at Graces Quarters, a former open-air chemical-agent facility at Aberdeen Proving Ground, Maryland, has resulted in ground-water contamination by chlorinated hydrocarbons. As part of a ground-water remediation feasibility study, a three-dimensional model was constructed to simulate transport of four chlorinated hydrocarbons (1,1,2,2-tetrachloroethane, trichloroethene, carbon tetrachloride, and chloroform) that are components of a contaminant plume in the surficial and middle aquifers underlying the east-central part of Graces Quarters. The model was calibrated to steady-state hydraulic head at 58 observation wells and to the concentration of 1,1,2,2-tetrachloroethane in 58 observation wells and 101direct-push probe samples from the mid-1990s. Simulations using the same basic model with minor adjustments were then run for each of the other plume constituents. The error statistics between the simulated and measured concentrations of each of the constituents compared favorably to the error statisticst,1,2,2-tetrachloroethane calibration. Model simulations were used in conjunction with contaminant concentration data to examine the sources and degradation of the plume constituents. It was determined from this that mixed contaminant sources with no ambient degradation was the best approach for simulating multi-species solute transport at the site. Forward simulations were run to show potential solute transport 30 years and 100 years into the future with and without source removal. Although forward simulations are subject to uncertainty, they can be useful for illustrating various aspects of the conceptual model and its implementation. The forward simulation with no source removal indicates that contaminants would spread throughout various parts of the surficial and middle aquifers, with the100-year simulation showing potential discharge areas in either the marshes at the end of the Graces Quarters peninsula or just offshore in the estuaries. The

  14. Comparative Genomics of the Ubiquitous, Hydrocarbon-degrading Genus Marinobacter

    Science.gov (United States)

    Singer, E.; Webb, E.; Edwards, K. J.

    2012-12-01

    The genus Marinobacter is amongst the most ubiquitous in the global oceans and strains have been isolated from a wide variety of marine environments, including offshore oil-well heads, coastal thermal springs, Antarctic sea water, saline soils and associations with diatoms and dinoflagellates. Many strains have been recognized to be important hydrocarbon degraders in various marine habitats presenting sometimes extreme pH or salinity conditions. Analysis of the genome of M. aquaeolei revealed enormous adaptation versatility with an assortment of strategies for carbon and energy acquisition, sensation, and defense. In an effort to elucidate the ecological and biogeochemical significance of the Marinobacters, seven Marinobacter strains from diverse environments were included in a comparative genomics study. Genomes were screened for metabolic and adaptation potential to elucidate the strategies responsible for the omnipresence of the Marinobacter genus and their remedial action potential in hydrocarbon-polluted waters. The core genome predominantly encodes for key genes involved in hydrocarbon degradation, biofilm-relevant processes, including utilization of external DNA, halotolerance, as well as defense mechanisms against heavy metals, antibiotics, and toxins. All Marinobacter strains were observed to degrade a wide spectrum of hydrocarbon species, including aliphatic, polycyclic aromatic as well as acyclic isoprenoid compounds. Various genes predicted to facilitate hydrocarbon degradation, e.g. alkane 1-monooxygenase, appear to have originated from lateral gene transfer as they are located on gene clusters of 10-20% lower GC-content compared to genome averages and are flanked by transposases. Top ortholog hits are found in other hydrocarbon degrading organisms, e.g. Alcanivorax borkumensis. Strategies for hydrocarbon uptake encoded by various Marinobacter strains include cell surface hydrophobicity adaptation via capsular polysaccharide biosynthesis and attachment

  15. Degradation of Total Petroleum Hydrocarbon in Phytoremediation Using Terrestrial Plants

    Directory of Open Access Journals (Sweden)

    Mushrifah Idris

    2014-06-01

    Full Text Available This study focused on the total petroleum hydrocarbon (TPH degradation in phytoremediation of spiked diesel in sand. The diesel was added to the sand that was planted with terrestrial plants. Four selected terrestrial plants used were Paspalum vaginatum Sw, Paspalums crobiculatum L. varbispicatum Hack, Eragrotis atrovirens (Desf. Trin. ex Steud and Cayratia trifolia (L. Domin since all the plants could survive at a hydrocarbon petroleum contaminated site in Malaysia. The samplings were carried out on Day 0, 7, 14, 28, 42 and 72. The analysis of the TPH was conducted by extracting the spiked sand using ultrasonic extraction. The determination of the TPH concentration in the sand was performed using GC-FID. The degradation of TPH depends on the plant species and time of exposure. The highest percentage degradation by P. vaginatum, P. scrobiculatum, E. atrovirens and C. trifolia were 91.9, 74.0, 68.9 and 62.9%, respectively. In conclusion, the ability to degrade TPH by plants were P. vaginatum > P. scrobiculatum > E. atrovirens> C. trifolia.

  16. Photo-assisted electrochemical degradation of simulated textile effluent coupled with simultaneous chlorine photolysis.

    Science.gov (United States)

    de Mello Florêncio, Thaíla; de Araújo, Karla Santos; Antonelli, Raissa; de Toledo Fornazari, Ana Luiza; da Cunha, Paula Cordeiro Rodrigues; da Silva Bontempo, Letícia Helena; de Jesus Motheo, Artur; Granato, Ana Claudia; Malpass, Geoffroy Roger Pointer

    2016-10-01

    The influence of chloride ion concentration during the photo-assisted electrochemical degradation of simulated textile effluent, using a commercial Ti/Ru0.3Ti0.7O2 anode, was evaluated. Initially, the effect of applied current and supporting electrolyte concentration on the conversion of chloride ions to form reactive chlorine species in 90 min of experiment was analyzed in order to determine the maximum production of reactive chlorine species. The optimum conditions encountered (1.5 A and 0.3 mol dm(-3) NaCl) were subsequently employed for the degradation of simulated textile effluent. The efficiency of the process was determined through the analysis of chemical oxygen demand (COD), total organic carbon (TOC), of the presence of organochlorine products and phytotoxicity. Photo-assisted electrochemical degradation was more efficient for COD and TOC removal than the electrochemical technique alone. With simultaneous UV irradiation, a reduced quantity of reactive chlorine was produced, indicating that photolysis of the chlorine species led to the formation of hydroxyl radicals. This fact turns a simple electrochemical process into an advanced oxidation process.

  17. Rush-hour aromatic and chlorinated hydrocarbons in selected subway stations of Shanghai, China

    Institute of Scientific and Technical Information of China (English)

    Yanli Zhang; Chunlei Li; Xinming Wang; Hai Guo; Yanli Feng; Jianmin Chen

    2012-01-01

    Air samples were collected simultaneously at platform,mezzanine and outdoor in five typical stations of subway system in Shanghai,China using stainless steel canisters and analyzed by gas chromatography-mass selective detector (GC-MSD) after cryogenic preconcentration.Benzene,toluene,ethylbenzene and xylenes (BTEX) at the platforms and mezzanines inside the stations averaged (10.3± 2.1),(38.7 ± 9.0),(19.4 ± 10.1) and (30.0 ± 11.1) μg/m3,respectively; while trichloroethylene (TrCE),tetrachloroethylene (TeCE)and para-dichlorobenzene (pDCB),vinyl chloride and carbon tetrachloride were the most abundant chlorinated hydrocarbons inside the stations with average levels of (3.6 ± 1.3),(1.3 ± 0.5),(4.1 ± 1.1),(2.2 ± 1.1) and (1.2 ± 0.3) μg/m3,respectively.Mean levels of major aromatic and chlorinated hydrocarbons were higher indoor (platforms and mezzanines) than outdoor with average indoor/outdoor (I/O)ratios of 1.1-9.5,whereas no significant indoor/outdoor differences were found except for benzene and TrCE.The highly significant mutual correlations (p < 0.01) for BTEX between indoor and outdoor and their significant correlation (p < 0.05) with methyl tert-butyl ether (MTBE),a marker of traffic-related emission without other indoor and outdoor sources,indicated that BTEX were introduced into the subway stations from indoor/outdoor air exchange and traffic emission should be their dominant source.TrCE and pDCB were mainly from indoor emission and TeCE might have both indoor emission sources and contribution from outdoor air,especially in the mezzanines.

  18. Rush-hour aromatic and chlorinated hydrocarbons in selected subway stations of Shanghai, China.

    Science.gov (United States)

    Zhang, Yanli; Li, Chunlei; Wang, Xinming; Guo, Hai; Feng, Yanli; Chen, Jianmin

    2012-01-01

    Air samples were collected simultaneously at platform, mezzanine and outdoor in five typical stations of subway system in Shanghai, China using stainless steel canisters and analyzed by gas chromatography-mass selective detector (GC-MSD) after cryogenic preconcentration. Benzene, toluene, ethylbenzene and xylenes (BTEX) at the platforms and mezzanines inside the stations averaged (10.3 +/- 2.1), (38.7 +/- 9.0), (19.4 +/- 10.1) and (30.0 +/- 11.1) microg/m3, respectively; while trichloroethylene (TrCE), tetrachloroethylene (TeCE) and para-dichlorobenzene (pDCB), vinyl chloride and carbon tetrachloride were the most abundant chlorinated hydrocarbons inside the stations with average levels of (3.6 +/- 1.3), (1.3 +/- 0.5), (4.1 +/- 1.1), (2.2 +/- 1.1) and (1.2 +/- 0.3) microg/m3, respectively. Mean levels of major aromatic and chlorinated hydrocarbons were higher indoor (platforms and mezzanines) than outdoor with average indoor/outdoor (I/O) ratios of 1.1-9.5, whereas no significant indoor/outdoor differences were found except for benzene and TrCE. The highly significant mutual correlations (p tert-butyl ether (MTBE), a marker of traffic-related emission without other indoor and outdoor sources, indicated that BTEX were introduced into the subway stations from indoor/outdoor air exchange and traffic emission should be their dominant source. TrCE and pDCB were mainly from indoor emission and TeCE might have both indoor emission sources and contribution from outdoor air, especially in the mezzanines. PMID:22783624

  19. Volatile Short-chain Chlorinated Hydrocarbons in the Groundwater of the City of Zagreb

    Directory of Open Access Journals (Sweden)

    Marijanović-Rajčić, M.

    2008-01-01

    Full Text Available The aim of the study was to assess the quality of the groundwater sampled from private wells and the public water-supply system in terms of estimating the contamination caused by short-chain chlorinated hydrocarbons, as well as to estimate the exposure of the citizens dwelling in different suburbs to these pollutants of their drinking water (Fig. 1. The aim of the study was also to determine which suburb is supplied through the public water-supply system with water originating from the Sašnak spring that is contaminated with volatile chlorinated short-chain hydrocarbons.Drinking water samples were taken from 3 private wells and 1 public water-supply system situated in 3 Zagreb suburbs - Pešćenica, Trnje, and Trešnjevka. The sampling was carried out during 2003 and was undertaken on a seasonal basis. Short-chain chlorinated hydrocarbons - 1,1,1-trichloroethane, carbon tetrachloride, 1,1,2-trichloroethene and 1,1,2,2-tetrachloroethene - were determined by gas chromatography, following "liquid-liquid extraction" in pentane. For that purpose, we applied the gas chromatograph equipped with an electron-capture detector, thermo-programmable operations, and a suitable capillary column. The technique applied was that of split-injection.The groundwater of the City of Zagreb was found to be contaminated with volatile chlorinated hydrocarbons. The concentration level of 1,1,1-trichloroethane, determined in most of the samples, was found to be low (Fig. 2. On the other hand, 1,1,2-trichloroethene was present in all samples in concentrations of about 1 µg l-1- (Fig. 3. Only the drinking water samples taken from private wells in the suburb of Trnje contained somewhat higher mass concentrations of 1,1,1-trichloroethane, with the peak value of 19.03 µg l-1, measured in the winter season. In the samples taken from private wells in Trnje, the mass concentrations of 1,1,2,2-tetrachloroethene rangedfrom 15.30 µg l-1 to 18.65 µg l-1, as measured in autumn

  20. Hydrocarbon degradation, plant colonization and gene expression of alkane degradation genes by endophytic Enterobacter ludwigii strains

    Energy Technology Data Exchange (ETDEWEB)

    Yousaf, Sohail [AIT Austrian Institute of Technology GmbH, Bioresources Unit, A-2444 Seibersdorf (Austria); Afzal, Muhammad [AIT Austrian Institute of Technology GmbH, Bioresources Unit, A-2444 Seibersdorf (Austria); National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad (Pakistan); Reichenauer, Thomas G. [AIT Austrian Institute of Technology GmbH, Environmental Resources and Technologies Unit, A-2444 Seibersdorf (Austria); Brady, Carrie L. [Forestry and Agricultural Biotechnology Institute, Department of Microbiology and Plant Pathology, University of Pretoria, Pretoria (South Africa); Sessitsch, Angela, E-mail: angela.sessitsch@ait.ac.at [AIT Austrian Institute of Technology GmbH, Bioresources Unit, A-2444 Seibersdorf (Austria)

    2011-10-15

    The genus Enterobacter comprises a range of beneficial plant-associated bacteria showing plant growth promotion. Enterobacter ludwigii belongs to the Enterobacter cloacae complex and has been reported to include human pathogens but also plant-associated strains with plant beneficial capacities. To assess the role of Enterobacter endophytes in hydrocarbon degradation, plant colonization, abundance and expression of CYP153 genes in different plant compartments, three plant species (Italian ryegrass, birdsfoot trefoil and alfalfa) were grown in sterile soil spiked with 1% diesel and inoculated with three endophytic E. ludwigii strains. Results showed that all strains were capable of hydrocarbon degradation and efficiently colonized the rhizosphere and plant interior. Two strains, ISI10-3 and BRI10-9, showed highest degradation rates of diesel fuel up to 68% and performed best in combination with Italian ryegrass and alfalfa. All strains expressed the CYP153 gene in all plant compartments, indicating an active role in degradation of diesel in association with plants. - Highlights: > E. ludwigii strains efficiently colonized plants in a non-sterile soil environment. > E. ludwigii strains efficiently expressed alkane degradation genes in plants. > E. ludwigii efficiently degraded alkane contaminations and promoted plant growth. > E. ludwigii interacted more effectively with Italian ryegrass than with other plants. > Degradation activity varied with plant and microbial genotype as well as with time. - Enterobacter ludwigii strains belonging to the E. cloacae complex are able to efficiently degrade alkanes when associated with plants and to promote plant growth.

  1. Degradation of chlorinated phenols by nanoscale zero-valent iron

    Institute of Scientific and Technical Information of China (English)

    Rong CHENG; Jianlong WANG; Weixian ZHANG

    2008-01-01

    Chlorophenols (CPs), as important contami-nants in groundwater, are toxic and difficult to biode-grade. Recently nanoscale zero-valent iron received a great deal of attention because of its excellent performance in treating recalcitrant compounds. In this study, nanoscale zero-valent iron particles were prepared using chemical reduction, and the reductive transformations of three kinds of chlorinated phenols (2-CP, 3-CP, and 4-CP) by nanoscale zero-valent iron under different conditions were investigated. The transformation process of the CPs was shown to be dechlorination first, then cleavage of the benzene ring. The removal efficiency of the CPs varied as follows: 2-CP3-CP4-CP. The reactivity of CPs was associated with their energy of lowest unoccupied molecular orbit (ELUMO). With the increase in initial concentrations of CPs, removal efficiency decreased a little. But the quantities of CPs reduced increased evidently. Temperature had influence on not only the removal efficiency, but also the transformation pathway. At higher temperatures, dechlorination occurred prior to benzene ring cleavage. At lower temperatures, however, the oxidation product was formed more easily.

  2. Chlorine

    Energy Technology Data Exchange (ETDEWEB)

    Talmage, Sylvia Smith [ORNL

    2009-01-01

    Following a brief description of the use of chlorine as a chemical warfare agent in World War I, this chapter summarizes physical and chemical data and recent clinical and controlled laboratory studies on the irritant and lethal effects of chlorine. The mechanism of toxicity for both irritation and lethal effects is described. The mathematical relationship between concentration and exposure duration for a set endpoint is given for both an irritancy response and mortality. This information can be used to assist in time-scaling for the set endpoint to other exposure durations. Risk assessment addresses the potential for greater effects in sensitive populations such as asthmatics. A concentration of 0.5 ppm for up to 8 hours is a no-adverse-effect concentration in most sensitive subjects; whereas, a concentration of 1.0 ppm induces some sensory irritation and transient changes in respiratory tract airflow parameters. Treatment and intervention of exposed individuals is dependent upon symptoms

  3. Degradation Characteristics and Community Structure of a Hydrocarbon Degrading Bacterial Consortium

    Institute of Scientific and Technical Information of China (English)

    Li Zheng; Gu Guizhou; Zhao Chaocheng; Zhao Dongfeng

    2015-01-01

    A hydrocarbon degrading bacterial consortium KO5-2 was isolated from oil-contaminated soil of Karamay in Xinjiang, China, which could remove 56.9%of 10 g/L total petroleum hydrocarbons (TPH) at 30℃after 7 days of incu-bation, and could also remove 100%of lfuorene, 98.93%of phenanthrene and 65.73%of pyrene within 3, 7 and 9 days, respectively. Twelve strains from six different genera were isolated from KO5-2 and only eight ones were able to utilize the TPH. The denaturing gradient gel electrophoresis (DGGE) was used to investigate the microbial community shifts in ifve different carbon sources (including TPH, saturated hydrocarbons, lfuorene, phenanthrene and pyrene). The test results indi-cated that the community compositions of KO5-2 in carbon sources of TPH and saturated hydrocarbons, respectively, were roughly the same, while they were distinctive in the three different carbon sources of PAHs. Rhodococcus sp. and Pseudo-monas sp. could survive in the ifve kinds of carbon sources. Bacillus sp., Sphingomonas sp. and Ochrobactrum sp. likely played key roles in the degradation of saturated hydrocarbons, PAHs and phenanthrene, respectively. This study showed that speciifc bacterial phylotypes were associated with different contaminants and complex interactions between bacterial spe-cies, and the medium conditions inlfuenced the biodegradation capacity of the microbial communities involved in bioreme-diation processes.

  4. Identification of Wastewater Bacteria Involved in the Degradation of Triclocarban and its Non-Chlorinated Congener

    OpenAIRE

    Miller, Todd R.; Colquhoun, David R.; Halden, Rolf U.

    2010-01-01

    Triclocarban (TCC) is an antimicrobial additive of personal care products that is only partially degraded during wastewater treatment. Bacteria responsible for its transformation are unknown. We obtained wastewater bacteria capable of using as the sole carbon source TCC or its non-chlorinated analog, carbanilide (NCC). Enrichments established using activated sludge amended with TCC and NCC, respectively, were maintained for one year through successive transfers. Enrichments displayed exponent...

  5. Fate and degradation of petroleum hydrocarbons in stormwater bioretention cells

    Science.gov (United States)

    LeFevre, Gregory Hallett

    This dissertation describes the investigation of the fate of hydrocarbons in stormwater bioretention areas and those mechanisms that affect hydrocarbon fate in such systems. Seventy-five samples from 58 bioretention areas were collected and analyzed to measure total petroleum hydrocarbon (TPH) residual and biodegradation functional genes. TPH residual in bioretention areas was greater than background sites but low overall (<3 µg/kg), and well below either the TPH concentration of concern or the expected concentration, assuming no losses. Bioretention areas with deep-root vegetation contained significantly greater quantites of bacterial 16S rRNA genes and two functional genes involved in hydrocarbon biodegradation. Field soils were capable of mineralizing naphthalene, a polycyclic aromatic hydrocarbon (PAH) when incubated in the laboratory. In an additional laboratory investigation, a column study was initiated to comprehensively determine naphthalene fate in a simulated bioretention cell using a 14C-labeled tracer. Sorption to soil was the greatest sink of naphthalene in the columns, although biodegradation and vegetative uptake were also important loss mechanisms. Little leaching occurred following the first flush, and volatilization was insignificant. Significant enrichment of naphthalene degrading bacteria occurred over the course of the experiment as a result of naphthalene exposure. This was evident from enhanced naphthalene biodegradation kinetics (measured via batch tests), significant increases in naphthalene dioxygenase gene quantities, and a significant correlation observed between naphthalene residual and biodegradation functional genes. Vegetated columns outperformed the unplanted control column in terms of total naphthalene removal and biodegradation kinetics. As a result of these experiments, a final study focused on why planted systems outperform unplanted systems was conducted. Plant root exudates were harvested from hydroponic setups for three

  6. Reproductive and morphological condition of wild mink (Mustela vison) and river otters (Lutra canadensis) in relation to chlorinated hydrocarbon contamination.

    OpenAIRE

    Harding, L E; Harris, M L; Stephen, C. R.; Elliott, J.E.

    1999-01-01

    We assessed chlorinated hydrocarbon contamination of mink and river otters on the Columbia and Fraser River systems of northwestern North America, in relation to morphological measures of condition. We obtained carcasses of mink and river otters from commercial trappers during the winters 1994-1995 and 1995-1996. Necropsies included evaluation of the following biological parameters: sex, body mass and length, age, thymus, heart, liver, lung, spleen, pancreas, kidney, gonad, omentum, adrenal g...

  7. PPCP degradation by UV/chlorine treatment and its impact on DBP formation potential in real waters.

    Science.gov (United States)

    Yang, Xin; Sun, Jianliang; Fu, Wenjie; Shang, Chii; Li, Yin; Chen, Yiwei; Gan, Wenhui; Fang, Jingyun

    2016-07-01

    The ultraviolet/chlorine (UV/chlorine) water purification process was evaluated for its ability to degrade the residues of pharmaceuticals and personal care products (PPCPs) commonly found in drinking water sources. The disinfection byproducts (DBPs) formed after post-chlorination were documented. The performance of the UV/chlorine process was compared with that of the UV/hydrogen peroxide (UV/H2O2) process in treating three types of sand-filtered natural water. Except caffeine and carbamazepine residues, the UV/chlorine process was found to be 59-99% effective for feed water with a high level of dissolved organic carbon and alkalinity, and 27-92% effective for water with a high ammonia content. Both chlorine radicals and hydroxyl radicals were found to contribute to the observed PPCP degradation. The removal efficiencies of chlorine- and UV-resistant PPCPs such as carbamazepine and caffeine were 2-3 times greater than in the UV/H2O2 process in waters not enriched with ammonia. UV/chlorine treatment slightly enhanced the formation chloral hydrate (CH), haloketone (HK) and trichloronitromethane (TCNM). It reduced haloacetonitrile (HAN) formation during the post-chlorination in comparison with the UV/H2O2 process. In waters with high concentrations of ammonia, the UV/chlorine process was only 5-7% more effective than the UV/H2O2 process, and it formed slightly more THMs, HKs and TCNM along with reduced formation of CH and HAN. The UV/chlorine process is thus recommended as a good alternative to UV/H2O2 treatment for its superior PPCP removal without significantly enhancing DBP formation.

  8. Reconstructing metabolic pathways of hydrocarbon-degrading bacteria from the Deepwater Horizon oil spill.

    Science.gov (United States)

    Dombrowski, Nina; Donaho, John A; Gutierrez, Tony; Seitz, Kiley W; Teske, Andreas P; Baker, Brett J

    2016-01-01

    The Deepwater Horizon blowout in the Gulf of Mexico in 2010, one of the largest marine oil spills(1), changed bacterial communities in the water column and sediment as they responded to complex hydrocarbon mixtures(2-4). Shifts in community composition have been correlated to the microbial degradation and use of hydrocarbons(2,5,6), but the full genetic potential and taxon-specific metabolisms of bacterial hydrocarbon degraders remain unresolved. Here, we have reconstructed draft genomes of marine bacteria enriched from sea surface and deep plume waters of the spill that assimilate alkane and polycyclic aromatic hydrocarbons during stable-isotope probing experiments, and we identify genes of hydrocarbon degradation pathways. Alkane degradation genes were ubiquitous in the assembled genomes. Marinobacter was enriched with n-hexadecane, and uncultured Alpha- and Gammaproteobacteria populations were enriched in the polycyclic-aromatic-hydrocarbon-degrading communities and contained a broad gene set for degrading phenanthrene and naphthalene. The repertoire of polycyclic aromatic hydrocarbon use varied among different bacterial taxa and the combined capabilities of the microbial community exceeded those of its individual components, indicating that the degradation of complex hydrocarbon mixtures requires the non-redundant capabilities of a complex oil-degrading community. PMID:27572965

  9. Methanogenic degradation of petroleum hydrocarbons in subsurface environments remediation, heavy oil formation, and energy recovery.

    Science.gov (United States)

    Gray, N D; Sherry, A; Hubert, C; Dolfing, J; Head, I M

    2010-01-01

    Hydrocarbons are common constituents of surface, shallow, and deep-subsurface environments. Under anaerobic conditions, hydrocarbons can be degraded to methane by methanogenic microbial consortia. This degradation process is widespread in the geosphere. In comparison with other anaerobic processes, methanogenic hydrocarbon degradation is more sustainable over geological time scales because replenishment of an exogenous electron acceptor is not required. As a consequence, this process has been responsible for the formation of the world's vast deposits of heavy oil, which far exceed conventional oil assets such as those found in the Middle East. Methanogenic degradation is also a potentially important component of attenuation in hydrocarbon contamination plumes. Studies of the organisms, syntrophic partnerships, mechanisms, and geochemical signatures associated with methanogenic hydrocarbon degradation have identified common themes and diagnostic markers for this process in the subsurface. These studies have also identified the potential to engineer methanogenic processes to enhance the recovery of energy assets as biogenic methane from residual oils stranded in petroleum systems.

  10. Limitations of microbial hydrocarbon degradation at the Amon mud volcano (Nile deep-sea fan

    Directory of Open Access Journals (Sweden)

    J. Felden

    2013-05-01

    Full Text Available The Amon mud volcano (MV, located at 1250 m water depth on the Nile deep-sea fan, is known for its active emission of methane and non-methane hydrocarbons into the hydrosphere. Previous investigations showed a low efficiency of hydrocarbon-degrading anaerobic microbial communities inhabiting the Amon MV center in the presence of sulfate and hydrocarbons in the seeping subsurface fluids. By comparing spatial and temporal patterns of in situ biogeochemical fluxes, temperature gradients, pore water composition, and microbial activities over 3 yr, we investigated why the activity of anaerobic hydrocarbon degraders can be low despite high energy supplies. We found that the central dome of the Amon MV, as well as a lateral mud flow at its base, showed signs of recent exposure of hot subsurface muds lacking active hydrocarbon degrading communities. In these highly disturbed areas, anaerobic degradation of methane was less than 2% of the methane flux. Rather high oxygen consumption rates compared to low sulfide production suggest a faster development of more rapidly growing aerobic hydrocarbon degraders in highly disturbed areas. In contrast, the more stabilized muds surrounding the central gas and fluid conduits hosted active anaerobic hydrocarbon-degrading microbial communities. The low microbial activity in the hydrocarbon-vented areas of Amon MV is thus a consequence of kinetic limitations by heat and mud expulsion, whereas most of the outer MV area is limited by hydrocarbon transport.

  11. Chlorinated hydrocarbons in coastal lagoons of the pacific coast of Nicaragua.

    Science.gov (United States)

    Carvalho, F P; Montenegro-Guillen, S; Villeneuve, J; Cattini, C; Bartocci, J; Lacayo, M; Cruz, A

    1999-02-01

    A screening for persistent chlorinated hydrocarbons was carried out in December 1995 in the main coastal lagoons on the Pacific side of Nicaragua, where most of the country's agriculture and pesticide use has been taking place for decades. Results for a wide range of organochlorine pesticides in lagoon sediments show levels that generally were very low in Estero Real, Estero Padre Ramos, and estuary of San Juan del Sur. For example, total DDTs in these lagoons averaged 4.5 +/- 3.4 ng g-1 dry weight, which may be considered a baseline level for the region. Other compounds such as HCHs, BHC, endosulfan, heptachlor, endrin, toxaphene, and aroclors were present in concentrations even lower, generally below 1 ng g-1 dry weight. However, sediments of the Esteros Naranjo-Paso Caballos system at Chinandega district contained pesticide residues in much higher levels, attaining maximum values of 1,420 ng g-1 and 270 ng g-1 dry weight, respectively, for toxaphene and total DDTs. Other compounds such as aroclors, chlordane, endosulfan, and dieldrin were also present in the sediments of this lagoon system, but in lower concentrations. The very high concentrations of toxaphene and DDTs in this lagoon are a result of the intensive use of these pesticides in cotton growing in the district of Chinandega. Due to the long environmental half-lives of these compounds (t(1/2) > 10 years in temperate soils), their concentrations in lagoon sediments will likely remain high for years to come. Based on these results, the development of the new shrimp farming activities in the Pacific coastal lagoons should be restricted to selected areas.

  12. Assessing breeding potential of peregrine falcons based on chlorinated hydrocarbon concentrations in prey

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, J.E. [Canadian Wildlife Service, Pacific Wildlife Research Centre, 5421 Robertson Rd., RR no. 1, Delta, British Columbia, V4K 3N2 (Canada)]. E-mail: john.elliott@ec.gc.ca; Miller, M.J. [Iolaire Ecological Consulting, 7899 Thrasher St., Mission, British Columbia, V2V 5H3 (Canada); Wilson, L.K. [Canadian Wildlife Service, Pacific Wildlife Research Centre, 5421 Robertson Rd., RR no. 1, Delta, British Columbia, V4K 3N2 (Canada)

    2005-03-01

    Peregrine falcons (Falco peregrinus) now breed successfully in most areas of North America from which they were previously extirpated. The loss during the mid-part of the last century of many of the world's peregrine populations was largely a consequence of impaired reproduction caused by the effects of DDE on eggshell quality and embryo hatchability. Population recovery has been attributed to re-introduction efforts, coupled with regulatory restrictions on the use of organochlorine pesticides. Peregrines have not returned to breed in some areas, such as the Okanagan Valley of British Columbia. That region has been extensively planted in fruit orchards which were treated annually with DDT during the early 1950s to the 1970s. Ongoing contamination of avian species, including potential peregrine prey, inhabiting orchards has been documented. In response to an initiative to release peregrines around the city of Kelowna in the Okanagan Valley, we collected potential peregrine prey species and analyzed whole bodies for chlorinated hydrocarbon residues. We used a simple bioaccumulation model to predict concentrations of DDE in peregrine eggs using concentrations in prey and estimates of dietary makeup as input. Peregrines would be expected to breed successfully only if they fed on a diet primarily of doves. Feeding on as little as 10% of other species such as starlings, robins, gulls and magpies would produce DDE concentrations in peregrine eggs greater than the threshold of 15 mg/kg. We also estimated the critical concentration of DDE in total prey to be about 0.5 mg/kg, one half of the previous most conservative criterion for peregrine prey. Concentrations of dieldrin and PCBs in peregrine prey are less than suggested critical levels. - Based on the level of DDE contamination of prey items, it seems unlikely that peregrine falcons could breed successfully throughout most of the Okanagan Valley of British Columbia.

  13. Chlorinated hydrocarbon pesticides and polychlorinated biphenyls in sediment cores from San Francisco Bay

    Science.gov (United States)

    Venkatesan, M.I.; De Leon, R. P.; VanGeen, A.; Luoma, S.N.

    1999-01-01

    Sediment cores of known chronology from Richardson and San Pablo Bays in San Francisco Bay, CA, were analyzed for a suite of chlorinated hydrocarbon pesticides and polychlorinated biphenyls to reconstruct a historic record of inputs. Total DDTs (DDT = 2,4'- and 4,4'-dichlorodiphenyltrichloroethane and the metabolites, 2,4'- and 4,4'-DDE, -DDD) range in concentration from 4-21 ng/g and constitute a major fraction (> 84%) of the total pesticides in the top 70 cm of Richardson Bay sediment. A subsurface maximum corresponds to a peak deposition date of 1969-1974. The first measurable DDT levels are found in sediment deposited in the late 1930's. The higher DDT inventory in the San Pablo relative to the Richardson Bay core probably reflects the greater proximity of San Pablo Bay to agricultural activities in the watershed of the Sacramento and San Joaquin rivers. Total polychlorinated biphenyls (PCBs) occur at comparable levels in the two Bays (inventories in San Pablo Bay are about a factor of four higher in the last four decades than in Richardson Bay, suggesting a distribution of inputs not as strongly weighed towards the upper reaches of the estuary as DDTs. The shallower subsurface maximum in PCBs compared to DDT in the San Pablo Bay core is consistent with the imposition of drastic source control measures four these constituents in 1970 and 1977 respectively. The observed decline in DDT and PCB levels towards the surface of both cores is consistent with a dramatic drop in the input of these pollutants once the effect of sediment resuspension and mixing is taken into account.

  14. Assessing chlorinated ethene degradation in a large scale contaminant plume by dual carbon–chlorine isotope analysis and quantitative PCR

    DEFF Research Database (Denmark)

    Hunkeler, D.; Abe, Y.; Broholm, Mette Martina;

    2011-01-01

    DCE. The significant enrichment of 13C in VC indicates that VC was transformed further, although the mechanismcould not be determined. The transformation of cDCEwas the rate limiting step as no accumulation of VC occurred. In summary, the study demonstrates that carbon–chlorine isotope analysis and qPCR combinedwith......The fate of chlorinated ethenes in a large contaminant plume originating from a tetrachloroethene (PCE) source in a sandy aquifer in Denmark was investigated using novel methods including compound-specific carbon and chlorine isotope analysis and quantitative real-time polymerase chain reaction (q......) concentrations remained low (b1 μg/L) and ethene was not observed. The correlated shift of carbon and chlorine isotope ratios of cDCE by 8 and 3.9‰, respectively, the detection of Dehaloccocides sp genes, and strongly reducing conditions in this zone provide strong evidence for reductive dechlorination of c...

  15. Isolation, identification, and crude oil degradation characteristics of a high-temperature, hydrocarbon-degrading strain.

    Science.gov (United States)

    Liu, Boqun; Ju, Meiting; Liu, Jinpeng; Wu, Wentao; Li, Xiaojing

    2016-05-15

    In this work, a hydrocarbon-degrading bacterium Y-1 isolated from petroleum contaminated soil in the Dagang Oilfield was investigated for its potential effect in biodegradation of crude oil. According to the analysis of 16S rRNA sequences, strain Y-1 was identified as Bacillus licheniformis. The growth parameters such as pH, temperature, and salinity were optimised and 60.2% degradation of crude oil removal was observed in 5days. The strain Y-1 showed strong tolerance to high salinity, alkalinity, and temperature. Emplastic produced by strain Y-1 at high temperatures could be applied as biosurfactant. Gas chromatography analysis demonstrated that the strain Y-1 efficiently degraded different alkanes from crude oil, and the emplastic produced by strain Y-1 promoted the degradation rates of long-chain alkanes when the temperature increased to 55°C. Therefore, strain Y-1 would play an important role in the area of crude oil contaminant bioremediation even in some extreme conditions. PMID:26994837

  16. Limitations of microbial hydrocarbon degradation at the Amon Mud Volcano (Nile Deep Sea Fan

    Directory of Open Access Journals (Sweden)

    J. Felden

    2013-01-01

    Full Text Available The Amon mud volcano (MV, located at 1250 m water depth on the Nile Deep Sea Fan, is known for its active emission of methane and non-methane hydrocarbons into the hydrosphere. Previous investigations showed a low efficiency of hydrocarbon-degrading anaerobic microbial communities inhabiting the Amon MV center in the presence of sulphate and hydrocarbons in the seeping subsurface fluids. By comparing spatial and temporal patterns of in situ biogeochemical fluxes, temperature gradients, pore water composition and microbial activities over three years, we investigated why the activity of anaerobic hydrocarbon degraders can be low despite high energy supplies. We found that the central dome of the Amon MV, as well as a lateral mud flow at its base, showed signs of recent exposure of hot subsurface muds lacking active hydrocarbon degrading communities. In these highly disturbed areas, anaerobic degradation of methane was less than 2% of the methane flux. Rather high oxygen consumption rates compared to low sulphide production suggest a faster development of more rapidly growing aerobic hydrocarbon degraders in highly disturbed areas. In contrast, the more stabilized muds surrounding the central gas and fluid conduits hosted active anaerobic hydrocarbon-degrading microbial communities. Furthermore, within three years, cell numbers and hydrocarbon degrading activity increased at the gas-seeping sites. The low microbial activity in the hydrocarbon-vented areas of Amon mud volcano is thus a consequence of kinetic limitations by heat and mud expulsion, whereas most of the outer mud volcano area is limited by hydrocarbon transport.

  17. Limitations of microbial hydrocarbon degradation at the Amon mud volcano (Nile deep-sea fan)

    NARCIS (Netherlands)

    Felden, J.; Lichtschlag, A.; Wenzhöfer, F.; de Beer, D.; Feseker, T.; Pop Ristova, P.; de Lange, G.; Boetius, A.

    2013-01-01

    The Amon mud volcano (MV), located at 1250m water depth on the Nile deep-sea fan, is known for its active emission of methane and non-methane hydrocarbons into the hydrosphere. Previous investigations showed a low efficiency of hydrocarbon-degrading anaerobic microbial communities inhabiting the Amo

  18. Assessment of semi-empirical mass transfer correlations for pervaporation treatment of wastewater contaminated with chlorinated hydrocarbons

    Institute of Scientific and Technical Information of China (English)

    LIU Sean X.; PENG Ming

    2006-01-01

    Assessment of mass transfer characteristics of pervaporation (PV) treatment of wastewater contaminated with chlorinated hydrocarbons is of great importance for water treatment plant operators conducting initial evaluation, process optimization,and process economics. While a membrane plays a central role in pervaporation processes and separation efficiency, the mass transfer in the liquid layer next to the membrane surface is of equal, if not greater importance. It is one of the few process parameters that can be adjusted in situ to manipulate the outcome ora pervaporation process. In this study, a bench scale pervaporation experiment of removing a common chlorinated hydrocarbon from water was carried out and the results of it were compared to the ones based on well-known semi-empirical correlations. The mass transfer coefficients from the experiments, ranging from 0.8×10-5~2.5×10-5 m/s under the operating conditions, are higher than those predicted by the correlation. The corresponding separation factors under varying flow velocities are determined to be between 310~950.

  19. Isolation and Screening of Hydrocarbon Degrading Bacterial Strains for Bioremediation of Petroleum Pollution in Qatar

    OpenAIRE

    Al Disi, Zulfa Ali

    2013-01-01

    Pollution, due to activities related to the oil industry, represents a serious threat to the natural environment. The application of biotechnological methods provides much safer and sustainable alternatives for bioremediation of polluted areas, using microorganisms. Several techniques for the isolation of hydrocarbon degrading bacteria have been investigated and published worldwide. A wide range of bilogical activities was shown. However, local hydrocarbon degrading strains and the factors af...

  20. Recent studies in microbial degradation of petroleum hydrocarbons in hypersaline environments

    Directory of Open Access Journals (Sweden)

    Babu Zhereppa Fathepure

    2014-04-01

    Full Text Available Many hypersaline environments are often contaminated with petroleum compounds. Among these, oil and natural gas production sites all over the world and hundreds of kilometers of coastlines in the more arid regions of Gulf countries are of major concern due to the extent and magnitude of contamination. Because conventional microbiological processes do not function well at elevated salinities, bioremediation of hypersaline environments can only be accomplished using high salt-tolerant microorganisms capable of degrading petroleum compounds. In the last two decades, there have been many reports on the biodegradation of hydrocarbons in moderate to high salinity environments. Numerous microorganisms belonging to the domain Bacteria and Archaea have been isolated and their phylogeny and metabolic capacity to degrade a variety of aliphatic and aromatic hydrocarbons in varying salinities have been demonstrated. This article focuses on our growing understanding of bacteria and archaea responsible for the degradation of hydrocarbons under aerobic conditions in moderate to high salinity conditions. Even though organisms belonging to various genera have been shown to degrade hydrocarbons, members of the genera Halomonas Alcanivorax, Marinobacter, Haloferax, Haloarcula, and Halobacterium dominate the published literature. Despite rapid advances in understanding microbial taxa that degrade hydrocarbons under aerobic conditions, not much is known about organisms that carry out similar processes in anaerobic conditions. Also, information on molecular mechanisms and pathways of hydrocarbon degradation in high salinity is scarce and only recently there have been a few reports describing genes, enzymes and breakdown steps for some hydrocarbons. These limited studies have clearly revealed that degradation of oxygenated and non-oxygenated hydrocarbons by halophilic and halotolerant microorganisms occur by pathways similar to those found in non-halophiles.

  1. Halotolerance and effect of salt on hydrophobicity in hydrocarbon-degrading bacteria.

    Science.gov (United States)

    Longang, Adégilns; Buck, Chris; Kirkwood, Kathlyn M

    2016-01-01

    Hydrocarbon-contaminated environments often also experience co-contamination with elevated levels of salt. This paper investigates the occurrence of halotolerance among several hydrocarbon-degrading bacteria, as an initial assessment of the importance of salt contamination to bioremediation strategies. Halotolerance was common, but not ubiquitous, among the 12 hydrocarbon-degrading bacteria tested, with many strains growing at up to 75 or 100 g NaCl L(-1) in rich medium. Greater sensitivity to elevated salt concentrations was observed among aromatics degraders compared to saturates degraders, and in defined medium compared to rich medium. Observed effects of high salt concentrations included increased lag times and decreased maximum growth. Many strains exhibited flocculation at elevated salt concentrations, but this did not correlate to any patterns in cell surface hydrophobicity, measured using the Bacterial Adhesion to Hydrocarbon assay. The occurrence of halotolerance in hydrocarbon-degrading bacteria suggests the potential for native microorganisms to contribute to the bioremediation of oil and salt co-contaminated sites, and indicates the need for a better understanding of the relationship between halotolerance and hydrocarbon biodegradation capabilities. PMID:26915518

  2. Microbial Degradation of Petroleum Hydrocarbon Contaminants: An Overview

    OpenAIRE

    Nilanjana Das; Preethy Chandran

    2010-01-01

    One of the major environmental problems today is hydrocarbon contamination resulting from the activities related to the petrochemical industry. Accidental releases of petroleum products are of particular concern in the environment. Hydrocarbon components have been known to belong to the family of carcinogens and neurotoxic organic pollutants. Currently accepted disposal methods of incineration or burial insecure landfills can become prohibitively expensive when amounts of contaminants are lar...

  3. Polyethylene as a source of artifacts in the paper chromatography of chlorinated hydrocarbon insecticides

    Science.gov (United States)

    Van Valin, C.C.; Kallman, B.J.; O'Donnell, J.J

    1963-01-01

    The introduction of artifacts from vessels, materials, and chemicals is a serious problem in the study of pesticide residues. It is therefore of interest to record findings that polyethylene wash bottles contain substances soluble in organic solvents and reactive with the silver nitrate chromogenic spray commonly employed in the paper chromatographic analysis of chlorinated organic insecticides.

  4. Intrinsic and enhanced bioremediation in aquifers contaminated with chlorinated and aromatic hydrocarbons in The Netherlands

    NARCIS (Netherlands)

    Rijnaarts, H.H.M.; Aalst-van Leeuwen, M.A. van; Heiningen, E. van; Buyzen, H. van; Sinke, A.; Liere, H.C. van; Harkes, M.; Baartmans, R.; Bosma, T.N.P.; Doddema, H.J.

    1998-01-01

    The feasibility of intrinsic and enhanced bioremediation approaches for 16 contaminated sites in the Netherlands are discussed. At at least five out of 10 chlorinated solvent sites, natural attenuation can be used as one of the tools to prevent further dispersion of the plume. At two sites stimulati

  5. SIMULATION OF PERFORMANCE OF CHLORINE-FREE FLURORINATED ETHERS AND FLUORINATED HYDROCARBONS TO REPLACE CFC-11 AND CFC-114 IN CHILLERS

    Science.gov (United States)

    The paper discusses simulation of the performance of chlorine-free fluorinated ethers and fluorinated hydrocarbons as potential long-term replacements for CFC-11 and -114. Modeling has been done with in-house refrigeration models based on the Carnahan-Starling-DeSantis Equation o...

  6. Enumeration and phylogenetic analysis of polycyclic aromatic hydrocarbon-degrading marine bacteria from Puget sound sediments.

    OpenAIRE

    Geiselbrecht, A D; Herwig, R P; Deming, J. W.; Staley, J T

    1996-01-01

    Naphthalene- and phenanthrene-degrading bacteria in Puget Sound sediments were enumerated by most-probable-number enumeration procedures. Sediments from a creosote-contaminated Environmental Protection Agency Superfund Site (Eagle Harbor) contained from 10(4) to 10(7) polycyclic aromatic hydrocarbon (PAH)-degrading bacteria g (dry weight) of sediment-1, whereas the concentration at an uncontaminated site ranged from 10(3) to 10(4) g of sediment(-1). Isolates of PAH-degrading bacteria were obt...

  7. Polycyclic Aromatic Hydrocarbon Degradation by a New Marine Bacterium, Neptunomonas naphthovorans gen. nov., sp. nov.

    OpenAIRE

    Hedlund, Brian P.; Geiselbrecht, Allison D.; Bair, Timothy J.; Staley, James T.

    1999-01-01

    Two strains of bacteria were isolated from creosote-contaminated Puget Sound sediment based on their ability to utilize naphthalene as a sole carbon and energy source. When incubated with a polycyclic aromatic hydrocarbon (PAH) compound in artificial seawater, each strain also degraded 2-methylnaphthalene and 1-methylnaphthalene; in addition, one strain, NAG-2N-113, degraded 2,6-dimethylnaphthalene and phenanthrene. Acenaphthene was not degraded when it was used as a sole carbon source but wa...

  8. Exploration of hydrocarbon degrading bacteria on soils contaminated by crude oil from South Sumatera

    Directory of Open Access Journals (Sweden)

    A. Napoleon

    2014-07-01

    Full Text Available The goal of this research was to explore hydrocarbon degrading bacteria on crude oil contaminated soil with potential to degrade hydrocarbon in oil pollutant. The research started by early August 2013 till January 2014. Soil sampling for this research was taken on several places with contaminated soil location such as Benakat, Rimau, and Pengabuan all of it located in South Sumatera. Conclusion from this research Isolates obtained from three (3 sites of contaminated soil and treated using SBS medium were Bacillus cereus, Pseudomonas aeruginosa, Klebsiella pnumoniae, Streptococcus beta hemolisa, Proteus mirabilis, Staphylococcus epidermis and Acinotobacter calcoaceticus. Isolates that survived on 300 ppm of hydrocarbon concentration were Bacillus cereus, Pseudomonas aeruginosa and Acinetobacter cakciaceticus Selected isolates posses the ability to degrade hydrocarbon by breaking hydrocarbon substance as the energy source to support isolates existence up to 1,67 TPH level. Based on results accomplish by this research, we urge for further research involving the capacity of isolates to degrade wide variety of hydrocarbon substance and more to develop the potential of these bacteria for bioremediation.

  9. A biogeochemical transport model to simulate the attenuation of chlorinated hydrocarbon contaminant fluxes across the groundwater-surface water interface

    DEFF Research Database (Denmark)

    Malaguerra, Flavio; Binning, Philip John; Albrechtsen, Hans-Jørgen

    2009-01-01

    Chlorinated hydrocarbons originating from point sources are amongst the most prevalent contaminants of ground water and surface water resources. Riparian zones may play an important role in the attenuation of contaminant concentrations when contaminant plumes flow from groundwater to surface water...... because of the occurrence of redox gradients, strongly reductive conditions and high biological activity. In order to meet the expectations of the EU Water Framework Directive, an evaluation of the impact of such plumes on surface water is needed. The aim of this work is to develop a groundwater transport...... number of geochemical processes, allows the simulation of soil geochemical transformations when microbial by-products are released to surface water, and the consideration of non-linear feedbacks on bacterial growth and pollutant transformations. Sensitivity analysis is performed through Monte Carlo...

  10. Isolation and Characterization of Hydrocarbon-Degrading Yeast Strains from Petroleum Contaminated Industrial Wastewater

    Directory of Open Access Journals (Sweden)

    Boutheina Gargouri

    2015-01-01

    Full Text Available Two yeast strains are enriched and isolated from industrial refinery wastewater. These strains were observed for their ability to utilize several classes of petroleum hydrocarbons substrates, such as n-alkanes and aromatic hydrocarbons as a sole carbon source. Phylogenetic analysis based on the D1/D2 variable domain and the ITS-region sequences indicated that strains HC1 and HC4 were members of the genera Candida and Trichosporon, respectively. The mechanism of hydrocarbon uptaking by yeast, Candida, and Trichosporon has been studied by means of the kinetic analysis of hydrocarbons-degrading yeasts growth and substrate assimilation. Biodegradation capacity and biomass quantity were daily measured during twelve days by gravimetric analysis and gas chromatography coupled with mass spectrometry techniques. Removal of n-alkanes indicated a strong ability of hydrocarbon biodegradation by the isolated yeast strains. These two strains grew on long-chain n-alkane, diesel oil, and crude oil but failed to grow on short-chain n-alkane and aromatic hydrocarbons. Growth measurement attributes of the isolates, using n-hexadecane, diesel oil, and crude oil as substrates, showed that strain HC1 had better degradation for hydrocarbon substrates than strain HC4. In conclusion, these yeast strains can be useful for the bioremediation process and decreasing petroleum pollution in wastewater contaminated with petroleum hydrocarbons.

  11. Use of the Complex Conductivity Method to Monitor Hydrocarbon Degradation in Brackish Environments

    Science.gov (United States)

    Ntarlagiannis, D.; Beaver, C. L.; Kimak, C.; Slater, L. D.; Atekwana, E. A.; Rossbach, S.

    2015-12-01

    Hydrocarbon contamination of the subsurface is a global environmental problem. The size, location and recurrence rate of contamination very often inhibits active remediation strategies. When there is no direct threat to humans, and direct/invasive remediation methods are prohibited, monitored natural attenuation is often the remediation method of choice. Consequently, long-term monitoring of hydrocarbon degradation is needed to validate remediation. Geophysical methods, frequently utilized to characterize subsurface contamination, have the potential to be adopted for long term monitoring of contaminant degradation. Over the last decade, the complex conductivity method has shown promise as a method for monitoring hydrocarbon degradation processes in freshwater environments. We investigated the sensitivity of complex conductivity to natural attenuation of oil in a brackish setting, being more representative of the conditions where most oil spills occur such as in coastal environments. We performed a series of laboratory hydrocarbon biodegradation experiments whilst continuously monitoring complex conductivity. Sediments from a beach impacted by the Deepwater Horizon (DWH) spill were used to provide the hydrocarbon degraders, while fluids with three different salinities, ranging from fresh water to brackish water, were used as the supporting media. All experimental columns, including two abiotic controls, were run in duplicate. Early results show a dependence of the complex conductivity parameters (both electrolytic and interfacial) on biodegradation processes. Despite the small signals relative to freshwater conditions, the imaginary part of the complex conductivity appears to be sensitive to biodegradation processes. The columns with highest salinity fluids - similar to the salinites for the site where the sediments were collected - showed distinctive complex conductivity responses similar to microbial growth curves. Geochemical monitoring confirmed elevated rates

  12. Polynuclear aromatic and chlorinated hydrocarbons in mussels from the coastal zone of Ushuaia, Tierra del Fuego, Argentina.

    Science.gov (United States)

    Amin, Oscar A; Comoglio, Laura I; Sericano, José L

    2011-03-01

    Mussels (Mytilus edulis chilensis) were collected from 12 coastal locations in Ushuaia Bay, Argentina, and the surrounding area in October 1999 and again in October 2003. Concentrations of polynuclear aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and selected chlorinated pesticides were determined to assess the impact of a fast-growing population in the area. Total PAH concentrations ranged from 2.24 to an extremely high concentration of 2,420 µg/g lipid measured in mussels collected near an oil jetty used to discharge to shore storage tanks. The composition of PAHs in these samples indicates that the source of these compounds inside Ushuaia Bay is predominantly petrogenic, with some pyrogenic background, whereas mostly pyrogenic-related PAHs were evident in areas outside the bay. Total concentrations of PCBs ranged between 12.8 and 8,210 ng/g lipid, with the highest concentration, detected inside Ushuaia harbor, representing a 10-fold increase when compared with historical data. Chlorinated pesticides were detected at comparatively lower concentrations, with 4-4'- 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene being the most common. The aggressive increase in population and related activities observed in the city of Ushuaia over the last two decades might have affected the environmental quality of the local bay. Moreover, the oceanographic and atmospheric conditions existing in Ushuaia Bay and surrounding areas may favor the accumulation and long-term presence of these organic pollutants in all compartments of this fragile environment. PMID:21128271

  13. Methanogenic degradation of petroleum hydrocarbons in subsurface environments remediation, heavy oil formation, and energy recovery.

    Science.gov (United States)

    Gray, N D; Sherry, A; Hubert, C; Dolfing, J; Head, I M

    2010-01-01

    Hydrocarbons are common constituents of surface, shallow, and deep-subsurface environments. Under anaerobic conditions, hydrocarbons can be degraded to methane by methanogenic microbial consortia. This degradation process is widespread in the geosphere. In comparison with other anaerobic processes, methanogenic hydrocarbon degradation is more sustainable over geological time scales because replenishment of an exogenous electron acceptor is not required. As a consequence, this process has been responsible for the formation of the world's vast deposits of heavy oil, which far exceed conventional oil assets such as those found in the Middle East. Methanogenic degradation is also a potentially important component of attenuation in hydrocarbon contamination plumes. Studies of the organisms, syntrophic partnerships, mechanisms, and geochemical signatures associated with methanogenic hydrocarbon degradation have identified common themes and diagnostic markers for this process in the subsurface. These studies have also identified the potential to engineer methanogenic processes to enhance the recovery of energy assets as biogenic methane from residual oils stranded in petroleum systems. PMID:20602990

  14. Degradation of benzene and other aromatic hydrocarbons by anaerobic bacteria

    NARCIS (Netherlands)

    Weelink, S.A.B.

    2008-01-01

    Accidental spills, industrial discharges and gasoline leakage from underground storage tanks have resulted in serious pollution of the environment with monoaromatic hydrocarbons, such as benzene, toluene, ethylbenzene and xylene (so-called BTEX). High concentrations of BTEX have been detected in soi

  15. Petroleum Hydrocarbon Degradation Potential of Soil Bacteria Native to the Yellow River Delta

    Institute of Scientific and Technical Information of China (English)

    WANG Zhen-Yu; GAO Dong-Mei; LI Feng-Min; ZHAO Jian; XIN Yuan-Zheng; S.SIMKINS; XING Bao-Shan

    2008-01-01

    The bioremediation potential of bacteria indigenous to soils of the Yellow River Delta in China was evaluated as a treatment option for soil remediation. Petroleum hydrocarbon degraders were isolated from contaminated soil samples from the Yellow River Delta. Four microbial communities and eight isolates were obtained. The optimal temperature, salinity, pH, and the ratios of C, N, and P (C:N:P) for the maximum biodegradation of diesel oil, crude oil, n-alkanes, and polyaromatic hydrocarbons by ndigenous bacteria were determined, and the kinetics changes in microbial communities were monitored. In general, the mixed microbial consortia demonstrated wider catabolic versatility and faster overall rate of hydrocarbon degradation than individual isolates. Our experimental results demonstrated the feasibility of biodegradation of petroleum hydrocarbon by indigenous bacteria for oil remediation in the Yellow River Delta.

  16. California sea lions (Zalophus californianus californianus) have lower chlorinated hydrocarbon contents in northern Baja California, Mexico, than in California, USA

    Energy Technology Data Exchange (ETDEWEB)

    Del Toro, Ligeia [Universidad Autonoma de Baja California (UABC), Facultad de Ciencias Marinas, Ensenada, Baja California (Mexico); Investigacion y Conservacion de Mamiferos Marinos de Ensenada, A.C., Placido Mata 2309 Depto. D-5, Condominio Las Fincas, Ensenada, Baja California 22810 (Mexico); Heckel, Gisela [Investigacion y Conservacion de Mamiferos Marinos de Ensenada, A.C., Placido Mata 2309 Depto. D-5, Condominio Las Fincas, Ensenada, Baja California 22810 (Mexico) and Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, B.C. Km 107 Carretera Tijuana-Ensenada, Ensenada, Baja California 22860 (Mexico)]. E-mail: gheckel@cicese.mx; Camacho-Ibar, Victor F. [Instituto de Investigaciones Oceanologicas, UABC, Apdo. Postal 453, Ensenada, Baja California 22860 (Mexico); Schramm, Yolanda [Universidad Autonoma de Baja California (UABC), Facultad de Ciencias Marinas, Ensenada, Baja California (Mexico); Investigacion y Conservacion de Mamiferos Marinos de Ensenada, A.C., Placido Mata 2309 Depto. D-5, Condominio Las Fincas, Ensenada, Baja California 22810 (Mexico)

    2006-07-15

    Chlorinated hydrocarbons (CHs) were determined in blubber samples of 18 California sea lions (Zalophus californianus californianus) that stranded dead along Todos Santos Bay, Ensenada, Baja California, Mexico, January 2000-November 2001. {sigma}DDTs were the dominant group (geometric mean 3.8 {mu}g/g lipid weight), followed by polychlorinated biphenyls ({sigma}PCBs, 2.96 {mu}g/g), chlordanes (0.12 {mu}g/g) and hexachlorocyclohexanes (0.06 {mu}g/g). The {sigma}DDTs/{sigma}PCBs ratio was 1.3. We found CH levels more than one order of magnitude lower than those reported for California sea lion samples collected along the California coast, USA, during the same period as our study. This sharp north-south gradient suggests that Z. californianus stranded in Ensenada (most of them males) would probably have foraged during the summer near rookeries 500-1000 km south of Ensenada and the rest of the year migrate northwards, foraging along the Baja California peninsula, including Ensenada, and probably farther north. - Results suggest that sea lion prey must also have lower hydrocarbons in Baja California than in California in the USA.

  17. Occurrence of fungi degrading aromatic hydrocarbons in activated sludge biocenoses

    Directory of Open Access Journals (Sweden)

    Anna Grabińska-Łoniewska

    2014-08-01

    Full Text Available A set of 21 strains of yeast-like microorganisms isolated from biocenoses of aerobic and anaerobic wastewater treatment systems were assayed for their ability to utilize aromatic hydrocarbons as a sole C-source. Basing on the achieved results, the highly biochemically active strains for application in enhancing of wastewaters and exhaust gases purification as well as soil bioremediation were selected.

  18. Degradation of benzene and other aromatic hydrocarbons by anaerobic bacteria

    OpenAIRE

    Weelink, S.A.B.

    2008-01-01

    Accidental spills, industrial discharges and gasoline leakage from underground storage tanks have resulted in serious pollution of the environment with monoaromatic hydrocarbons, such as benzene, toluene, ethylbenzene and xylene (so-called BTEX). High concentrations of BTEX have been detected in soils, sediments and groundwater. The mobility and toxicity of the BTEX compounds are of major concern. In situ bioremediation of BTEX by using naturally occurring microorganisms or introduced microor...

  19. Complete degradation of polychlorinated hydrocarbons by a two-stage biofilm reactor.

    OpenAIRE

    Fathepure, B Z; Vogel, T M

    1991-01-01

    A two-stage anaerobic-aerobic biofilm reactor successfully degraded a mixture of chlorinated organic compounds to water-soluble metabolic intermediates and carbon dioxide. Reductive dechlorination of hexachlorobenzene (HCB), tetrachloroethylene (PCE), and chloroform (CF) occurred on all tested primary carbon sources such as glucose, methanol, and acetate. However, the extent of dechlorination was maximum when the anaerobic biofilm column was fed acetate as a primary carbon source. HCB, PCE, a...

  20. Anaerobic Microbial Degradation of Hydrocarbons: From Enzymatic Reactions to the Environment.

    Science.gov (United States)

    Rabus, Ralf; Boll, Matthias; Heider, Johann; Meckenstock, Rainer U; Buckel, Wolfgang; Einsle, Oliver; Ermler, Ulrich; Golding, Bernard T; Gunsalus, Robert P; Kroneck, Peter M H; Krüger, Martin; Lueders, Tillmann; Martins, Berta M; Musat, Florin; Richnow, Hans H; Schink, Bernhard; Seifert, Jana; Szaleniec, Maciej; Treude, Tina; Ullmann, G Matthias; Vogt, Carsten; von Bergen, Martin; Wilkes, Heinz

    2016-01-01

    Hydrocarbons are abundant in anoxic environments and pose biochemical challenges to their anaerobic degradation by microorganisms. Within the framework of the Priority Program 1319, investigations funded by the Deutsche Forschungsgemeinschaft on the anaerobic microbial degradation of hydrocarbons ranged from isolation and enrichment of hitherto unknown hydrocarbon-degrading anaerobic microorganisms, discovery of novel reactions, detailed studies of enzyme mechanisms and structures to process-oriented in situ studies. Selected highlights from this program are collected in this synopsis, with more detailed information provided by theme-focused reviews of the special topic issue on 'Anaerobic biodegradation of hydrocarbons' [this issue, pp. 1-244]. The interdisciplinary character of the program, involving microbiologists, biochemists, organic chemists and environmental scientists, is best exemplified by the studies on alkyl-/arylalkylsuccinate synthases. Here, research topics ranged from in-depth mechanistic studies of archetypical toluene-activating benzylsuccinate synthase, substrate-specific phylogenetic clustering of alkyl-/arylalkylsuccinate synthases (toluene plus xylenes, p-cymene, p-cresol, 2-methylnaphthalene, n-alkanes), stereochemical and co-metabolic insights into n-alkane-activating (methylalkyl)succinate synthases to the discovery of bacterial groups previously unknown to possess alkyl-/arylalkylsuccinate synthases by means of functional gene markers and in situ field studies enabled by state-of-the-art stable isotope probing and fractionation approaches. Other topics are Mo-cofactor-dependent dehydrogenases performing O2-independent hydroxylation of hydrocarbons and alkyl side chains (ethylbenzene, p-cymene, cholesterol, n-hexadecane), degradation of p-alkylated benzoates and toluenes, glycyl radical-bearing 4-hydroxyphenylacetate decarboxylase, novel types of carboxylation reactions (for acetophenone, acetone, and potentially also benzene and

  1. Anaerobic Microbial Degradation of Hydrocarbons: From Enzymatic Reactions to the Environment.

    Science.gov (United States)

    Rabus, Ralf; Boll, Matthias; Heider, Johann; Meckenstock, Rainer U; Buckel, Wolfgang; Einsle, Oliver; Ermler, Ulrich; Golding, Bernard T; Gunsalus, Robert P; Kroneck, Peter M H; Krüger, Martin; Lueders, Tillmann; Martins, Berta M; Musat, Florin; Richnow, Hans H; Schink, Bernhard; Seifert, Jana; Szaleniec, Maciej; Treude, Tina; Ullmann, G Matthias; Vogt, Carsten; von Bergen, Martin; Wilkes, Heinz

    2016-01-01

    Hydrocarbons are abundant in anoxic environments and pose biochemical challenges to their anaerobic degradation by microorganisms. Within the framework of the Priority Program 1319, investigations funded by the Deutsche Forschungsgemeinschaft on the anaerobic microbial degradation of hydrocarbons ranged from isolation and enrichment of hitherto unknown hydrocarbon-degrading anaerobic microorganisms, discovery of novel reactions, detailed studies of enzyme mechanisms and structures to process-oriented in situ studies. Selected highlights from this program are collected in this synopsis, with more detailed information provided by theme-focused reviews of the special topic issue on 'Anaerobic biodegradation of hydrocarbons' [this issue, pp. 1-244]. The interdisciplinary character of the program, involving microbiologists, biochemists, organic chemists and environmental scientists, is best exemplified by the studies on alkyl-/arylalkylsuccinate synthases. Here, research topics ranged from in-depth mechanistic studies of archetypical toluene-activating benzylsuccinate synthase, substrate-specific phylogenetic clustering of alkyl-/arylalkylsuccinate synthases (toluene plus xylenes, p-cymene, p-cresol, 2-methylnaphthalene, n-alkanes), stereochemical and co-metabolic insights into n-alkane-activating (methylalkyl)succinate synthases to the discovery of bacterial groups previously unknown to possess alkyl-/arylalkylsuccinate synthases by means of functional gene markers and in situ field studies enabled by state-of-the-art stable isotope probing and fractionation approaches. Other topics are Mo-cofactor-dependent dehydrogenases performing O2-independent hydroxylation of hydrocarbons and alkyl side chains (ethylbenzene, p-cymene, cholesterol, n-hexadecane), degradation of p-alkylated benzoates and toluenes, glycyl radical-bearing 4-hydroxyphenylacetate decarboxylase, novel types of carboxylation reactions (for acetophenone, acetone, and potentially also benzene and

  2. Degradation characteristics of metoprolol during UV/chlorination reaction and a factorial design optimization.

    Science.gov (United States)

    Nam, Seung-Woo; Yoon, Yeomin; Choi, Dae-Jin; Zoh, Kyung-Duk

    2015-03-21

    Metoprolol (MTP), a hypertension depressor, has been increasingly detected even after conventional water treatment processes. In this study, the removal of MTP was compared using chlorination (Cl2), UV-C photolysis, and UV/chlorination (Cl2/UV) reactions. The results showed that the UV/chlorination reaction was most effective for MTP removal. MTP removal during UV/chlorination reaction was optimized under various conditions of UV intensity (1.1-4.4 mW/cm(2)), chlorine dose (1-5 mg/L as Cl2), pH (2-9), and dissolved organic matter (DOM, 1-4 mgC/L) using a two-level factorial design with 16 experimental combinations of the four factors. Among the factors examined, DOM scavenging by OH radicals was the most dominant in terms of MTP removal during UV/chlorination reaction. The established model fit well with the experimental results using to various water samples including surface waters, filtered and tap water samples. The optimized conditions (UV intensity=4.4 mW/cm(2), [Cl2]=5 mg/L, pH 7, and [DOM]=0.8-1.1 mgC/L) of the model removed more than 78.9% of MTP for filtered water samples during UV/chlorination reaction. Using LC-MS/MS, five byproducts of MTP (molecular weight: 171, 211, 309, 313, and 341, respectively) were identified during UV/chlorination reaction. Based on this information, the MTP transformation mechanism during UV/chlorination was suggested. Our results imply that applying UV/chlorination process after filtration stage in the water treatment plant (WTP) would be the most appropriate for effective removal of MTP.

  3. Biofuel components change the ecology of bacterial volatile petroleum hydrocarbon degradation in aerobic sandy soil

    International Nuclear Information System (INIS)

    We tested the hypothesis that the biodegradation of volatile petroleum hydrocarbons (VPHs) in aerobic sandy soil is affected by the blending with 10 percent ethanol (E10) or 20 percent biodiesel (B20). When inorganic nutrients were scarce, competition between biofuel and VPH degraders temporarily slowed monoaromatic hydrocarbon degradation. Ethanol had a bigger impact than biodiesel, reflecting the relative ease of ethanol compared to methyl ester biodegradation. Denaturing gradient gel electrophoresis (DGGE) of bacterial 16S rRNA genes revealed that each fuel mixture selected for a distinct bacterial community, each dominated by Pseudomonas spp. Despite lasting impacts on soil bacterial ecology, the overall effects on VHP biodegradation were minor, and average biomass yields were comparable between fuel types, ranging from 0.40 ± 0.16 to 0.51 ± 0.22 g of biomass carbon per gram of fuel carbon degraded. Inorganic nutrient availability had a greater impact on petroleum hydrocarbon biodegradation than fuel composition. Highlights: ► The effect of 10% ethanol or 20% biodiesel on the biodegradability of volatile petroleum hydrocarbons in soil was investigated. ► Competition for scarce inorganic nutrients between biofuel and VPH degraders slowed monoaromatic hydrocarbon degradation. ► Biofuel effects were transitional. ► Each fuel selected for a distinct predominant bacterial community. ► All bacterial communities were dominated by Pseudomonas spp. - Blending of petroleum with ethanol or biodiesel changes the fuel degrading soil bacterial community structure, but the long-term effects on fuel biodegradability are minor.

  4. Assessment of in situ degradation of chlorinated ethenes and bacterial community structure in a complex contaminated groundwater system.

    Science.gov (United States)

    Imfeld, Gwenaël; Nijenhuis, Ivonne; Nikolausz, Marcell; Zeiger, Simone; Paschke, Heidrun; Drangmeister, Jörg; Grossmann, Jochen; Richnow, Hans H; Weber, Stefanie

    2008-02-01

    The occurrence of in situ degradation of chlorinated ethenes was investigated using an integrated approach in a complex groundwater system consisting of several geological units. The assessment of hydrogeochemistry and chlorinated ethenes distribution using principal component analysis (PCA) in combination with carbon stable isotope analysis revealed that chlorinated ethenes were subjected to substantial biodegradation. Shifts in isotopic values up to 20.4 per thousand, 13.9 per thousand, 20.1 per thousand and 31.4 per thousand were observed between geological units for tetrachloroethene (PCE), trichloroethene (TCE), cis-dichloroethene (cDCE) and vinyl chloride (VC), respectively. The use of specific biomarkers (16S rRNA gene) indicated the presence of Dehalococcoides sp. DNA in 20 of the 33 evaluated samples. In parallel, the analysis of changes in the bacterial community composition in the aquifers using canonical correspondence analysis (CCA) indicated the predominant influence of the chlorinated ethene concentrations (56.3% of the variance, P=0.005). The integrated approach may open new prospects for the assessment of spatial and temporal functioning of bioattenuation in contaminated groundwater systems. PMID:17915287

  5. Evaluating potential chlorinated methanes degradation mechanisms and treatments in interception trenches filled with concrete-based construction wastes

    Science.gov (United States)

    Rodríguez-Fernandez, Diana; Torrentó, Clara; Rosell, Mònica; Audí-Miró, Carme; Soler, Albert

    2014-05-01

    A complex mixture of chlorinated organic compounds is located in an unconfined carbonated bedrock aquifer with low permeability in a former industrial area next to Barcelona (NE Spain). The site exhibited an especially high complexity due to the presence of multiple contaminant sources, wide variety of pollutants (mainly chlorinated ethenes but also chlorinated methanes) and unknown system of fractures (Palau et al., 2014). Interception trenches were installed in the place of the removed pollution sources and were filled with construction wastes with the aim of retaining and treating the accumulated contaminated recharge water before reaching the aquifer. Recycled concrete-based aggregates from a construction and demolition waste recycling plant were used to maintain alkaline conditions in the water accumulated in the trenches (pH 11.6±0.3) and thus induce chloroform (CF) degradation by alkaline hydrolysis. An efficacy of around 30-40% CF degradation in the interception trenches was calculated from the significant and reproducible CF carbon isotopic fractionation (-53±3o obtained in batch experiments (Torrentó et al., 2014). Surprisingly, although hydrolysis of carbon tetrachloride (CT) is extremely slow, a significant CT carbon isotopic enrichment was also observed in the trenches. The laboratory experiments verified the low capability of concrete to hydrolyze the CT and showed the high adsorption of CT on the concrete particles (73% after 50 days) with invariability in its δ13C values. Therefore, the significant CT isotopic fractionation observed in the interception trenches could point out the occurrence of other degradation processes distinct than alkaline hydrolysis. Geochemical speciation modelling using the code PHREEQC showed that water collected at the trenches is supersaturated with respect to several iron oxy-hydroxides and therefore, CT degradation processes related to these iron minerals cannot be discarded. In addition, the combination of alkaline

  6. Improvement of Bioremediation Performance for the Degradation of Petroleum Hydrocarbons in Contaminated Sediments

    Directory of Open Access Journals (Sweden)

    Laura Rocchetti

    2011-01-01

    Full Text Available Microcosm bioremediation strategies were applied to sediments contaminated with hydrocarbons. Experiments were performed in aerobic conditions in a single-step treatment and in a two-step anaerobic-aerobic treatment. In aerobic conditions, either inorganic nutrients or composts were added to the microcosms, while, in the first anaerobic phase of the two-step experiment, acetate and/or allochthonous sulfate-reducing bacteria were used. After the treatment under anaerobic conditions, samples were exposed to aerobic conditions in the presence of compost. In the aerobic treatments, 81% hydrocarbon biodegradation was observed after 43 days in the presence of inorganic nutrients. In aerobic conditions in the presence of mature compost, hydrocarbon biodegradation was 51% after 43 days of treatment, whereas it was 47% after 21 days with fresh compost. The two-step experiment allowed us to obtain a hydrocarbon degradation of 91%, after a first anaerobic step with an inoculum of sulfate-reducing prokaryotes.

  7. Variability of Biological Degradation of Aromatic Hydrocarbons in an Aerobic Aquifer Determined by Laboratory Batch Experiments

    DEFF Research Database (Denmark)

    Nielsen, Per Henning; Christensen, Thomas Højlund

    1994-01-01

    The biological aerobic degradation of 7 aromatic hydrocarbons (benzene, toluene, o-xylene, p-dichlorobenzene, o-dichlorobenzene, naphthalene and biphenyl) was studied for 149 days in replicate laboratory batch experiments with groundwater and sediment from 8 localities representing a 15 m × 30 m...... section of an aerobic aquifer. Compared to biologically deactivated control experiments all compounds were biologically degraded. Degradation curves were very reproducible for some compounds (benzene, toluene, o-xylene, o-dichlorobenzene and p-dichlorobenzene) and less reproducible for other (naphthalene...... and biphenyl). Based on observed length of lag phases, length of the degradation periods and percent degradation, the variation among the 8 localities appears to be modest. However, detailed examination of the degradation rates revealed statistically significant variation among localities for benzene, toluene...

  8. Proteogenomic Characterization of Monocyclic Aromatic Hydrocarbon Degradation Pathways in the Aniline-Degrading Bacterium Burkholderia sp. K24.

    Directory of Open Access Journals (Sweden)

    Sang-Yeop Lee

    Full Text Available Burkholderia sp. K24, formerly known as Acinetobacter lwoffii K24, is a soil bacterium capable of utilizing aniline as its sole carbon and nitrogen source. Genomic sequence analysis revealed that this bacterium possesses putative gene clusters for biodegradation of various monocyclic aromatic hydrocarbons (MAHs, including benzene, toluene, and xylene (BTX, as well as aniline. We verified the proposed MAH biodegradation pathways by dioxygenase activity assays, RT-PCR, and LC/MS-based quantitative proteomic analyses. This proteogenomic approach revealed four independent degradation pathways, all converging into the citric acid cycle. Aniline and p-hydroxybenzoate degradation pathways converged into the β-ketoadipate pathway. Benzoate and toluene were degraded through the benzoyl-CoA degradation pathway. The xylene isomers, i.e., o-, m-, and p-xylene, were degraded via the extradiol cleavage pathways. Salicylate was degraded through the gentisate degradation pathway. Our results show that Burkholderia sp. K24 possesses versatile biodegradation pathways, which may be employed for efficient bioremediation of aniline and BTX.

  9. Local and seasonal variations in concentrations of chlorinated polycyclic aromatic hydrocarbons associated with particles in a Japanese megacity.

    Science.gov (United States)

    Ohura, Takeshi; Kamiya, Yuta; Ikemori, Fumikazu

    2016-07-15

    Concentrations of particle-bound polycyclic aromatic hydrocarbons (PAHs) and chlorinated PAHs (ClPAHs) were measured in different seasons at five sampling stations in Nagoya, a Japanese megacity. The annual mean total ClPAH and total PAH concentrations were 43.3-92.6pg/m(3) and 5200-8570pg/m(3), respectively. The concentrations of total ClPAHs were significantly variable than those of total PAHs, and both total concentrations through the seasons did not significantly correlate at any of the stations. Principal component analysis was used to characterize the ClPAH sources, resulted that ClPAHs were found to be associated with the sources of high-molecular-weight PAHs in the warmer seasons and of low-molecular-weight PAHs in the colder seasons. These findings suggest that principal sources of particle-bound ClPAHs are present in the local area, and change in the seasons. Toxic equivalent (TEQ) concentrations were estimated to assess the risks associated with exposure to ClPAHs in air. The TEQ concentrations in the samples were 0.05-0.32pg-TEQ/m(3). The TEQ concentrations in summer were approximately half the TEQ concentrations in the other seasons at all of the stations. PMID:27037480

  10. Chlorinated hydrocarbons in tuna homogenate IAEA-351: Results of a world-wide exercise. ILMR intercalibration exercise report no. 44

    International Nuclear Information System (INIS)

    The present intercalibration exercise provides, once again, strong evidence for insufficient data quality for chlorinated hydrocarbons in marine samples. This comment must be considered in perspective. The principle aim of these exercises is not just to obtain narrower confidence intervals for a given parameter moreover it is to guarantee that the data generated by monitoring exercises is of sufficient quality to evaluate contaminant levels, gradients and trends in the environment. All data should be accurate but precision (expressed as confidence limits) may vary according to its application. It is clearly not the same problem to measure DDT for human health protection (legal concentration limits in seafood range from about 1000-5000 ng/g) as it is to monitor environmental trends where values in biota are commonly one to three orders of magnitude lower. Even the 8 laboratories achieving 'good' data for pp'DDT would not be able to statistically distinguish a 35% increase of the concentration of this parameter from 30-41 ng/g on the basis of the precision observed in the present exercise. Fortunately spatial gradients for DDTs tend to be much larger than this and significant changes could be easily detected by the 'good' labs provided that they use adequate quality control procedures

  11. Hydrocarbon-Degrading Bacteria Exhibit a Species-Specific Response to Dispersed Oil while Moderating Ecotoxicity.

    Science.gov (United States)

    Overholt, Will A; Marks, Kala P; Romero, Isabel C; Hollander, David J; Snell, Terry W; Kostka, Joel E

    2016-01-01

    The Deepwater Horizon blowout in April 2010 represented the largest accidental marine oil spill and the largest release of chemical dispersants into the environment to date. While dispersant application may provide numerous benefits to oil spill response efforts, the impacts of dispersants and potential synergistic effects with crude oil on individual hydrocarbon-degrading bacteria are poorly understood. In this study, two environmentally relevant species of hydrocarbon-degrading bacteria were utilized to quantify the response to Macondo crude oil and Corexit 9500A-dispersed oil in terms of bacterial growth and oil degradation potential. In addition, specific hydrocarbon compounds were quantified in the dissolved phase of the medium and linked to ecotoxicity using a U.S. Environmental Protection Agency (EPA)-approved rotifer assay. Bacterial treatment significantly and drastically reduced the toxicity associated with dispersed oil (increasing the 50% lethal concentration [LC50] by 215%). The growth and crude oil degradation potential of Acinetobacter were inhibited by Corexit by 34% and 40%, respectively; conversely, Corexit significantly enhanced the growth of Alcanivorax by 10% relative to that in undispersed oil. Furthermore, both bacterial strains were shown to grow with Corexit as the sole carbon and energy source. Hydrocarbon-degrading bacterial species demonstrate a unique response to dispersed oil compared to their response to crude oil, with potentially opposing effects on toxicity. While some species have the potential to enhance the toxicity of crude oil by producing biosurfactants, the same bacteria may reduce the toxicity associated with dispersed oil through degradation or sequestration. PMID:26546426

  12. Reproductive success and chlorinated hydrocarbon contamination of resident great blue herons (Ardea herodias) from coastal British Columbia, Canada, 1977 to 2000

    International Nuclear Information System (INIS)

    Human disturbance and loss of nesting habitat were more important factors than chlorinated hydrocarbons in changing heron reproductive success. - Over the period 1977-2000, eggs of Pacific great blue heron (Ardea herodias fannini) were collected from 23 colonies along the southern coast of British Columbia, Canada, and analyzed for persistent organochlorine (OC) pesticides and polychlorinated biphenyls (PCBs). Concentrations of OC pesticides in eggs declined sharply in the late 1970s, after which there were minimal changes. The sums of PCB congeners were not reduced appreciably during the 1980s and 1990s, but Aroclor 1260 concentrations suggested a sharp decline in PCB contamination of eggs in the late 1970s, similar to that shown for OC pesticides. Eggs collected along or near the Fraser River delta showed higher levels of most pesticides compared to other monitored colonies. Although the delta lands support a long-standing agricultural economy, the primary factors influencing OC levels in the delta colonies were thought to be driven by estuarine processes. We suggest two possible influencing factors were: 1) a greater rate of bioaccumulation in the estuary due to the deposition of particulates collected over a vast area encompassed by the Fraser River watershed; or 2) a higher rate of biomagnification in the estuary due to species differences at lower trophic levels of the heron food chain. Eggs from urban colonies contained higher levels of PCBs. The congener pattern was not clearly different from that observed in less contaminated eggs from rural and pulp mill-influenced colonies, except that colonies in Vancouver had greater proportions of PCB-66, suggesting a local source of Aroclor 1242. Productivity in the coastal heron colonies was highly variable over the period of study, with 71% of recorded colony-wide reproductive failures occurring in colonies near pulp mills. However, the predominant factors influencing reproductive success were probably disturbance

  13. Microbial degradation of street dust polycyclic aromatic hydrocarbons in microcosms simulating diffuse pollution of urban soil

    DEFF Research Database (Denmark)

    Johnsen, Anders R; de Lipthay, Julia R; Sørensen, Søren J;

    2006-01-01

    Diffuse pollution with polycyclic aromatic hydrocarbons (PAHs) of topsoil in urban regions has caused increasing concerns in recent years. We simulated diffuse pollution of soil in microcosms by spiking sandy topsoil (A-horizon) and coarse, mineral subsoil (C-horizon) with street dust (PM63......) isolated from municipal street sweepings from central Copenhagen. The microbial communities adapted to PAH degradation in microcosms spiked with street dust in both A-horizon and C-horizon soils, in spite of low PAH-concentrations. The increased potential for PAH degradation was demonstrated on several...... levels: by slowly diminishing PAH-concentrations, increased mineralization of 14C-PAHs, increasing numbers of PAH degraders and increased prevalence of nah and pdo1 PAH degradation genes, i.e. the microbial communities quickly adapted to PAH degradation. Three- and 4-ring PAHs from the street dust were...

  14. Aromatic Hydrocarbons: Degrading Bacteria in the Desert Soil of Kuwait

    International Nuclear Information System (INIS)

    Soil samples of different levels of oil pollutants were collected from Kuwait's Burgan Oil Field, near an oil lake. The samples represented, highly polluted (8.0% w/w), moderately polluted (2.1%-3.4%) and slightly polluted (2.1%-3.4%) and slightly polluted (0.5- 0.8%). The aromatic fractions of the collected samples were in the range of (0.21-2.57g/100g) soil. (GC) analysis of the aromatic fractions of the resolution of the different individual (PAHs) revealed the presence of (16) different (PAHs) resolved from the aromatic fraction of the highly polluted sample (S3). (15), (14) and (13) individual (PAHs) were identified soil samples (S5), (S2) and (S1, S4, S6) respectively. The most frequent (PAH) was indeno (1, 2, 3-c, d) pyrene (22.5%-45.11%) followed chrysene (13.6%-19.48%). Eight carcinogenic (PAHs) were resolved from the aromatic fractions of the polluted samples. Total carcinogenic (PAHs) recorded in this study were in this study were in the range of (11.53) (forS4) - (510.98) (for S3) ppm. The counts of (CFU) of aromatic degraders (AD) were in the range of (3x10) - (110x 10) (CFU/g) soil (with a percent of (2.2%-69.6%)). The results show that, higher counts of (AD) were recorded from a highly polluted sample (S3), followed by the moderately polluted samples; total of (51) bacteria, that gave presumptive positive biodegradation activities, were isolated and identified (45.1%) of them were isolated and identified. (45.1%) of them were isolated from the highly polluted sample (S3). Total of (13) different species were identified of which Micrococcus luteus was more frequent (23.5) followed by Bacillus licheniformis (19.6%) and Bacillus subtilis (11.8%). The three Pseudomonas species collectively were presented by (11.8%). Five different species proved to be of good activities, they are: Bacillus brevis, Bacillus lichenoformis, Pseudomonas aeruginosa, Pseudomonas stutzeri and Pseudomonas flourescens. The ability of five species and their mixture was

  15. Bioassays with terrestrial and aquatic species as monitoring tools of hydrocarbon degradation.

    Science.gov (United States)

    Bori, Jaume; Vallès, Bettina; Ortega, Lina; Riva, Maria Carme

    2016-09-01

    In this study chemical analyses and ecotoxicity tests were applied for the assessment of a heavily hydrocarbon-contaminated soil prior and after the application of a remediation procedure that consisted in the stimulation of soil autochthonous populations of hydrocarbon degraders in static-ventilated biopiles. Terrestrial bioassays were applied in mixtures of test soils and artificial control soil and studied the survival and reproduction of Eisenia fetida and the avoidance response of E. fetida and Folsomia candida. Effects on aquatic organisms were studied by means of acute tests with Vibrio fischeri, Raphidocelis subcapitata, and Daphnia magna performed on aqueous elutriates from test soils. The bioremediation procedure led to a significant reduction in the concentration of hydrocarbons (from 34264 to 3074 mg kg(-1), i.e., 91 % decrease) and toxicity although bioassays were not able to report a percentage decrease of toxicity as high as the percentage reduction. Sublethal tests proved the most sensitive terrestrial bioassays and avoidance tests with earthworms and springtails showed potential as monitoring tools of hydrocarbon remediation due to their high sensitivity and short duration. The concentrations of hydrocarbons in water extracts from test soils were 130 and 100 μg L(-1) before and after remediation, respectively. Similarly to terrestrial tests, most aquatic bioassays detected a significant reduction in toxicity, which was almost negligible at the end of the treatment. D. magna survival was the most affected by soil elutriates although toxicity to the crustacean was associated to the salinity of the samples rather than to the concentration of hydrocarbons. Ecotoxicity tests with aqueous soil elutriates proved less relevant in the assessment of hydrocarbon-contaminated soils due to the low hydrosolubility of hydrocarbons and the influence of the physicochemical parameters of the aquatic medium. PMID:27312898

  16. Marine coastal sediments microbial hydrocarbon degradation processes: contribution of experimental ecology in the omics’era

    Directory of Open Access Journals (Sweden)

    Cristiana eCravo-Laureau

    2014-02-01

    Full Text Available Coastal marine sediments, where important biological processes take place, supply essential ecosystem services. By their location, such ecosystems are particularly exposed to human activities as evidenced by the recent Deepwater Horizon disaster. This catastrophe revealed the importance to better understand the microbial processes involved on hydrocarbon degradation in marine sediments raising strong interests of the scientific community. During the last decade, several studies have shown the key role played by microorganisms in determining the fate of hydrocarbons in oil-polluted sediments but only few have taken into consideration the whole sediment’s complexity. Marine coastal sediment ecosystems are characterized by remarkable heterogeneity, owning high biodiversity and are subjected to fluctuations in environmental conditions, especially to important oxygen oscillations due to tides. Thus, for understanding the fate of hydrocarbons in such environments, it is crucial to study microbial activities, taking into account sediment characteristics, physical-chemical factors (electron acceptors, temperature, nutrients, co-metabolites availability as well as sediment’s reworking due to bioturbation activities. Key information could be collected from in situ studies, which provide an overview of microbial processes, but it is difficult to integrate all parameters involved. Microcosm experiments allow to dissect in-depth some mechanisms involved in hydrocarbon degradation but exclude environmental complexity. To overcome these lacks, strategies have been developed, by creating experiments as close as possible to environmental conditions, for studying natural microbial communities subjected to oil pollution. We present here a review of these approaches, their results and limitation, as well as the promising future of applying ‘omics’ approaches to characterize in-depth microbial communities and metabolic networks involved in hydrocarbon

  17. ASSESSMENT OF PETROLEUM HYDROCARBON DEGRADATION FROM SOIL AND TARBALL BY FUNGI

    OpenAIRE

    Sakineh Lotfinasabasl1, V. R.Gunale1, N. S. Rajurkar 1, 2

    2012-01-01

    Four fungi strains viz. Aspergillus niger, Aspergillus terreus, Rhizopus sp and Penicillium sp were isolated from soil and tarball samples collected from mangrove forest of Alibaug and Akshi coastal area, Maharashtra, India. These strains were assessed for their degradation capability of petroleum hydrocarbons measuring growth diameter in Potato Dextrose Agar (PDA) solid media for different concentrations of kerosene (5%- 20% (v/v)). Rhizopus sp showed the highest growth diameter in 5% kerose...

  18. Aerobic cometabolic degradation of chlorinated ethenes in a two step system

    NARCIS (Netherlands)

    Sipkema, EM; Mocoroa, J; deKoning, W; Vlieg, JETV; Ganzeveld, KJ; Beenackers, AACM; Janssen, DB

    1997-01-01

    Many of the chlorinated ethenes (CEs) can aerobically only be converted by cometabolism, a process in which the organism converts the contaminant that it cannot use for growth as a result of the nonspecificity of one of its enzymes. For bioremediation systems, the methanotroph Methylosinus trichospo

  19. High bacterial biodiversity increases degradation performance of hydrocarbons during bioremediation of contaminated harbor marine sediments

    International Nuclear Information System (INIS)

    We investigated changes of bacterial abundance and biodiversity during bioremediation experiments carried out on oxic and anoxic marine harbor sediments contaminated with hydrocarbons. Oxic sediments, supplied with inorganic nutrients, were incubated in aerobic conditions at 20 °C and 35 °C for 30 days, whereas anoxic sediments, amended with organic substrates, were incubated in anaerobic conditions at the same temperatures for 60 days. Results reported here indicate that temperature exerted the main effect on bacterial abundance, diversity and assemblage composition. At higher temperature bacterial diversity and evenness increased significantly in aerobic conditions, whilst decreased in anaerobic conditions. In both aerobic and anaerobic conditions, biodegradation efficiencies of hydrocarbons were significantly and positively related with bacterial richness and evenness. Overall results presented here suggest that bioremediation strategies, which can sustain high levels of bacterial diversity rather than the selection of specific taxa, may significantly increase the efficiency of hydrocarbon degradation in contaminated marine sediments. - Highlights: ► Bioremediation performance was investigated on hydrocarbon contaminated sediments. ► Major changes in bacterial diversity and assemblage composition were observed. ► Temperature exerted the major effect on bacterial assemblages. ► High bacterial diversity increased significantly biodegradation performance. This should be considered for sediment remediation by bio-treatments. - Bioremediation strategies which can sustain high levels of bacterial diversity may significantly increase the biodegradation of hydrocarbons in contaminated marine sediments.

  20. Salinity and Conductivity Amendment of Soil Enhanced the Bioelectrochemical Degradation of Petroleum Hydrocarbons.

    Science.gov (United States)

    Li, Xiaojing; Wang, Xin; Zhang, Yueyong; Zhao, Qian; Yu, Binbin; Li, Yongtao; Zhou, Qixing

    2016-01-01

    The extreme salinity and high internal resistance of saline-alkali soil contaminated by petroleum hydrocarbons were two key limitations for using the bioelectrochemical remediation. In order to solve two problems, we simply rinsed soil, added carbon fiber to polluted soil. The charge output was enhanced by 110% with increase of the maximum current densities from 81 to 304 mA·m(-2) while hydrocarbons degradation rate enhanced by 484%, especially the high molecular weight fractions (C28-C36 of n-alkanes and 4-6 rings of PAHs). These effects were possibly due to the selective enrichment of species belonged to δ-Proteobacteria (Proteobacteria), Flavobacteriia (Bacteroidetes) or Clostridia (Firmicutes), the activities of biological electron transfer and enzymes. As we know, oxygenase gene that directly decided the process of degradation, was surveyed for the first time in soil bioelectrochemical remediation system. The results confirmed that the bio-current stimulated the activities of naphthalene dioxygenase and xylene monooxygenase and thus the hydrocarbons degradation and the electricity generation. Given that electricity generation and the remediation performance are governed by multiple factors, understanding of microbial community and enzyme gene is crucial to promote the power yield and the bioelectrochemical remediation applicability. PMID:27597387

  1. Quantification of temperature impacts on the dissolution of chlorinated hydrocarbons into groundwater

    Science.gov (United States)

    Koproch, Nicolas; Popp, Steffi; Köber, Ralf; Beyer, Christof; Bauer, Sebastian; Dahmke, Andreas

    2016-04-01

    Shallow thermal energy storage has great potential for heat storage especially in urban and industrial areas. However, frequently existing organic groundwater contaminations in such areas were currently seen as exclusion criteria for thermal use of the shallow subsurface, since increased contaminant discharge is feared as consequence of heating. Contaminant discharge is influenced by a complex interaction of processes and boundary conditions as e.g. solubility, dispersion, viscosity and degradation, where there is still a lack of experimental evidence of the temperature dependent interaction. Even existing studies on basic influencing factors as e.g. temperature dependent solubilities show contradictory results. Such knowledge gaps should be reduced to improve the basis and liability of numerical model simulations and the knowledge base to enable a more differentiated and optimized use of resources. For this purpose batch as well as 1- and 2-dimensional experimental studies concerning the temperature dependent release of TCE (trichloroethylene) from a NAPL (non aqueous phase liquid) source are presented and discussed. In addition, this experimental studies are accompanied by a numerical model verification, where extensions of existing numerical model approaches on basis of this obtained experimental results are developed. Firstly, temperature dependent TCE solubility data were collected using batch experiments with significantly better temperature resolution compared to earlier studies, showing a distinct minimum at 35°C and increased solubility towards 5°C and 70°C. Secondly, heated 1-dimensional stainless steel columns homogenously filled with quartz sand were used to quantify source zone depletion and contaminant discharge at 10-70°C. Cumulative mass discharge curves indicated two blob categories with distinct differences in dissolution kinetics. Increasing the temperature showed here an increase of the amount of fast dissolving blobs indicating higher NAPL

  2. Functional Gene Markers for Fumarate-Adding and Dearomatizing Key Enzymes in Anaerobic Aromatic Hydrocarbon Degradation in Terrestrial Environments.

    Science.gov (United States)

    von Netzer, Frederick; Kuntze, Kevin; Vogt, Carsten; Richnow, Hans H; Boll, Matthias; Lueders, Tillmann

    2016-01-01

    Anaerobic degradation is a key process in many environments either naturally or anthropogenically exposed to petroleum hydrocarbons. Considerable advances into the biochemistry and physiology of selected anaerobic degraders have been achieved over the last decades, especially for the degradation of aromatic hydrocarbons. However, researchers have only recently begun to explore the ecology of complex anaerobic hydrocarbon degrader communities directly in their natural habitats, as well as in complex laboratory systems using tools of molecular biology. These approaches have mainly been facilitated by the establishment of a suite of targeted marker gene assays, allowing for rapid and directed insights into the diversity as well as the identity of intrinsic degrader populations and degradation potentials established at hydrocarbon-impacted sites. These are based on genes encoding either peripheral or central key enzymes in aromatic compound breakdown, such as fumarate-adding benzylsuccinate synthases or dearomatizing aryl-coenzyme A reductases, or on aromatic ring-cleaving hydrolases. Here, we review recent advances in this field, explain the different detection methodologies applied, and discuss how the detection of site-specific catabolic gene markers has improved the understanding of processes at contaminated sites. Functional marker gene-based strategies may be vital for the development of a more elaborate population-based assessment and prediction of aromatic degradation potentials in hydrocarbon-impacted environments. PMID:26959523

  3. Impact of Inoculation Protocols, Salinity, and pH on the Degradation of Polycyclic Aromatic Hydrocarbons (PAHs) and Survival of PAH-Degrading Bacteria Introduced into Soil

    OpenAIRE

    Kästner, Matthias; Breuer-Jammali, Maren; Mahro, Bernd

    1998-01-01

    Degradation of polycyclic aromatic hydrocarbons (PAHs) and survival of bacteria in soil was investigated by applying different inoculation protocols. The soil was inoculated with Sphingomonas paucimobilis BA 2 and strain BP 9, which are able to degrade anthracene and pyrene, respectively. CFU of soil bacteria and of the introduced bacteria were monitored in native and sterilized soil at different pHs. Introduction with mineral medium inhibited PAH degradation by the autochthonous microflora a...

  4. Intercalibration of analytical methods on marine environmental samples. Results of MEDPOL-II exercise for the intercalibration of chlorinated hydrocarbon measurements on mussel homogenate (MA-M-2/OC)

    International Nuclear Information System (INIS)

    Mussels have been considered as good indicators of chlorinated hydrocarbon pollution of the marine environment and this led to the development of mussel watch programmes in many countries in the late seventies. These intercalibration exercises were arranged in order to increase the quality of analytical capabilities of environmental laboratories. The samples MA-M-2/0C of Mediterranean mussels with chlorinated hydrocarbon content were checked by 27 laboratories. It was judged highly suitable for these laboratories to have at their disposal a reference material made of mussel tissue with robust estimations of the true values with respect to several chlorinated hydrocarbons. Such a material would allow chemists to check the validity of new analytical procedures

  5. Degradation and O-methylation of chlorinated phenolic compounds by Rhodococcus and Mycobacterium strains.

    OpenAIRE

    Häggblom, M M; Nohynek, L J; Salkinoja-Salonen, M. S.

    1988-01-01

    Three polychlorophenol-degrading Rhodococcus and Mycobacterium strains were isolated independently from soil contaminated with chlorophenol wood preservative and from sludge of a wastewater treatment facility of a kraft pulp bleaching plant. Rhodococcus sp. strain CG-1 and Mycobacterium sp. strain CG-2, isolated from tetrachloroguaiacol enrichment, and Rhodococcus sp. strain CP-2, isolated from pentachlorophenol enrichment, mineralized pentachlorophenol and degraded several other polychlorina...

  6. Aerobic degradation of highly chlorinated polychlorobiphenyls by a marine bacterium, Pseudomonas CH07

    Digital Repository Service at National Institute of Oceanography (India)

    De, J.; Ramaiah, N.; Sarkar, A.

    and the other coplanar tetrachloro congener CB-77 was degraded by more than 40% within 40 hours by this microorganism. Apparently absence of bphC in this bacterium led to proposition of different mechanism of PCBs degradation. KEY WORDS: Pseudomonas CH07...

  7. Anaerobic degradation of cyclohexane by sulfate-reducing bacteria from hydrocarbon-contaminated marine sediments

    Directory of Open Access Journals (Sweden)

    Ulrike eJaekel

    2015-02-01

    Full Text Available The fate of cyclohexane, often used as a model compound for the biodegradation of cyclic alkanes due to its abundance in crude oils, in anoxic marine sediments has been poorly investigated. In the present study, we obtained an enrichment culture of cyclohexane-degrading sulfate-reducing bacteria from hydrocarbon-contaminated intertidal marine sediments. Microscopic analyses showed an apparent dominance by oval cells of 1.5×0.8 m. Analysis of a 16S rRNA gene library, followed by whole-cell hybridization with group- and sequence-specific oligonucleotide probes showed that these cells belonged to a single phylotype, and were accounting for more than 80% of the total cell number. The dominant phylotype, affiliated with the Desulfosarcina-Desulfococcus cluster of the Deltaproteobacteria, is proposed to be responsible for the degradation of cyclohexane. Quantitative growth experiments showed that cyclohexane degradation was coupled with the stoichiometric reduction of sulfate to sulfide. Substrate response tests corroborated with hybridization with a sequence-specific oligonucleotide probe suggested that the dominant phylotype apparently was able to degrade other cyclic and n-alkanes, including the gaseous alkanes propane and n-butane. Based on GC-MS analyses of culture extracts cyclohexylsuccinate was identified as a metabolite, indicating an activation of cyclohexane by addition to fumarate. Other metabolites detected were 3-cyclohexylpropionate and cyclohexanecarboxylate providing evidence that the overall degradation pathway of cyclohexane under anoxic conditions is analogous to that of n-alkanes.

  8. Reconstruction of metabolic networks in a fluoranthene-degrading enrichments from polycyclic aromatic hydrocarbon polluted soil.

    Science.gov (United States)

    Zhao, Jian-Kang; Li, Xiao-Ming; Ai, Guo-Min; Deng, Ye; Liu, Shuang-Jiang; Jiang, Cheng-Ying

    2016-11-15

    Microbial degradation of polycyclic aromatic hydrocarbons (PAHs) is the primary process of removing PAHs from environments. The metabolic pathway of PAHs in pure cultures has been intensively studied, but cooperative metabolisms at community-level remained to be explored. In this study, we determined the dynamic composition of a microbial community and its metabolic intermediates during fluoranthene degradation using high-throughput metagenomics and gas chromatography-mass spectrometry (GC-MS), respectively. Subsequently, a cooperative metabolic network for fluoranthene degradation was constructed. The network shows that Mycobacterium contributed the majority of ring-hydroxylating and -cleavage dioxygenases, while Diaphorobacter contributed most of the dehydrogenases. Hyphomicrobium, Agrobacterium, and Sphingopyxis contributed to genes encoding enzymes involved in downstream reactions of fluoranthene degradation. The contributions of various microbial groups were calculated with the PICRUSt program. The contributions of Hyphomicrobium to alcohol dehydrogenases were 62.4% in stage 1 (i.e., when fluoranthene was rapidly removed) and 76.8% in stage 3 (i.e., when fluoranthene was not detectable), respectively; the contribution of Pseudomonas were 6.6% in stage 1 and decreased to 1.2% in subsequent stages. To the best of the author's knowledge, this report describes the first cooperative metabolic network to predict the contributions of various microbial groups during PAH-degradation at community-level. PMID:27415596

  9. CONTINUOUS-MODE PHOTOCATALYTIC DEGRADATION OF CHLORINATED PHENOLS AND PESTICIDES IN WATER USING A BENCH-SCALE TIO2 ROTATING DISK REACTOR

    Science.gov (United States)

    Photocatalytic degradation of phenol, chlorinated phenols, and lindane was evaluated in a continuous flow TiOz rotating disk photocatalytic reactor (RDPR). The RDPR operated at a hydraulic residence time of 0.25 day and at a disk angular velocity of 12 rpm. At low molar feed conc...

  10. Membrane filtration process and bioreactor for elimination of chlorinated hydrocarbons from industrial effluents; Membranfiltration und Bioreaktor zur Eliminierung chlorierter Kohlenwasserstoffe aus Industrieabwaessern

    Energy Technology Data Exchange (ETDEWEB)

    Schierenbeck, A.

    2003-07-01

    Selective separation and elimination of chlorinated hydrocarbons from industrial effluents directly at the production site was to be achieved by a combined process including membrane technology and biodegradation. This way, closed cycle processes can be designed which will be a major contribution to environmental protection integrated in production processes. First, chlorinated hydrocarbons are characterized in terms of occurrence and biodegradability. Two model substances are discussed (3-chlorobenzoic acid and 4-chlorophenol), and a practical example is presented. The fundamentals of the processes used for treatment of industrial effluents are outlined, and their advantages and shortcomings are discussed, with particular regard to integrated application in production processes. [German] Das Ziel dieser Arbeit ist die Entwicklung einer Verfahrenstechnik, bei der durch die Kombination der Membrantechnik mit dem biologischen Abbau die selektive Abtrennung und Eliminierung chlorierter Kohlenwasserstoffe aus dem Industrieabwasser schon am Ort des Entstehens realisiert werden. Durch den Einsatz dieser Technik wird die Schliessung von Wasserkreislaeufen moeglich. Dies stellt fuer alle Bereiche, in denen chlorierte Kohlenwasserstoffe in das Abwasser gelangen koennen, einen wichtigen Beitrag zum produktionsintegrierten Umweltschutz dar. Dazu wird zunaechst die Problemstoffgruppe der chlorierten Kohlenwasserstoffe hinsichtlich ihres Auftretens und der biologischen Abbaubarkeit charakterisiert. Zwei Modellsubstanzen (3-Chlorbenzoesaeure und 4-Chlorphenol) werden diskutiert sowie ein Beispiel aus der Praxis vorgestellt, bei dem ein Abwasser mit chlorierten Kohlenwasserstoffen anfaellt. Die Grundlagen der verwendeten Verfahren zur Behandlung von Industrieabwaessern mit entsprechenden Abwasserinhaltsstoffen werden dargestellt. Die Moeglichkeiten und Grenzen dieser Verfahren, insbesondere im Hinblick auf den produktionsintegrierten Einsatz, werden diskutiert. (orig.)

  11. Use of Advanced Oxidation and Aerobic Degradation for Remediation of Various Hydrocarbon Contaminates

    Energy Technology Data Exchange (ETDEWEB)

    Paul Fallgren

    2009-03-06

    Western Research Institute in conjunction with Sierra West Consultants, Inc., Tetra Tech, Inc., and the U.S. Department of Energy conducted laboratory and field studies to test different approaches to enhance degradation of hydrocarbons and associated contaminants. WRI in conjunction with Sierra West Consultants, Inc., conducted a laboratory and field study for using ozone to treat a site contaminated with MTBE and other hydrocarbons. Results from this study demonstrate that a TOD test can be used to resolve the O{sub 3} dosage problem by establishing a site-specific benchmark dosage for field ozone applications. The follow-up testing of the laboratory samples provided indications that intrinsic biodegradation could be stimulated by adding oxygen. Laboratory studies also suggests that O3 dosage in the full-scale field implementation could be dialed lower than stoichiometrically designed to eliminate the formation of Cr(VI). WRI conducted a study involving a series of different ISCO oxidant applications to diesel-contaminated soil and determined the effects on enhancing biodegradation to degrade the residual hydrocarbons. Soils treated with permanganate followed by nutrients and with persulfate followed by nutrients resulted in the largest decrease in TPH. The possible intermediates and conditions formed from NOM and TPH oxidation by permanganate and activated persulfate favors microbial TPH degrading activity. A 'passive-oxidation' method using microbial fuel cell (MFC) technology was conducted by WRI in conjunction with Tetra Tech, Inc., to degrade MTBE in groundwater. These experiments have demonstrated that a working MFC (i.e., one generating power) could be established in the laboratory using contaminated site water or buffered media inoculated with site water and spiked with MTBE, benzene, or toluene. Electrochemical methods were studied by WRI with goal of utilizing low voltage and amperage electrical sources for 'geo-oxidation' of organic

  12. Life in oil :Hydrocarbon-degrading bacterial mineralization in oil spill-polluted marine environment

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The biodegradation of hydrocarbons by microorganisms is one of the primary ways by which an oil spill is eliminated from contaminated sites.One such spill was that of the Russian tanker the Nakhodka that spilled heavy oil into the Sea of Japan on January 2,1997.This paper describes the three main processes of the Nakhodka oil spill,including:(1) the weathering of hydrocarbon-degrading bacteria (genus Pseudomonas)and crystallized organic compounds from the Nakhodka oil spill-polluted seashores after nine years;(2) the laboratory-scale biodegradation of the Nakhodka oil spill over a 429-day period;and (3) the bioavailability of kaolinite clay minerals and the role they play in seawater polluted with the Nakhodka oil spill.Upon the slow evaporation of the Nakhodka oil spill during the 9-year weathering,the dendritic crystal growth of paraffin (a mixture of alkanes) occurred in the oil crust under natural conditions.Heavy metals were obtained in the original heavy oil samples of three seashores in the Sea of Japan.Si,S,Ti,Cr,Ni,Cu,and Zn were found in the original Nakhodka oil spill samples whereas these heavy metals and S were no longer present after 9 years.The anaerobic reverse side of the oil crust contained numerous coccus-type bacteria associated with halite.The hydrocarbon-degrading bacteria and paraffin wax in the oil crust may have a significant effect on the weathering processes of the Nakhodka oil spill during the 9-year bioremediation.A biodegradation process of heavy oil from the Nakhodka oil spill by indigenous microbial consortia was monitored over 429 days in the laboratory.The indigenous microbial consortia consisted of bacteria and fungi as well as the bacterium Pseudomonas aeruginosa isolated from Atake seashore,Ishikawa Prefecture,Japan.Both bacteria and fungi had a significant role in the observed biodegradation of heavy oil during the 429-day bioremediation with respect to the pH of the solution.Hydrocarbon-degrading bacteria had a tendency to

  13. Stable carbon isotope fractionation in chlorinated ethene degradation by bacteria expressing three toluene oxygenases

    Directory of Open Access Journals (Sweden)

    Scott eClingenpeel

    2012-02-01

    Full Text Available One difficulty in using bioremediation at a contaminated site is demonstrating that biodegradation is actually occurring in situ. The stable isotope composition of contaminants may help with this, since they can serve as an indicator of biological activity. To use this approach it is necessary to establish how a particular biodegradation pathway affects the isotopic composition of a contaminant. This study examined bacterial strains expressing three aerobic enzymes for their effect on the 13C/12C ratio when degrading both trichloroethene (TCE and cis-1,2-dichloroethene (c-DCE: toluene 3-monoxygenase, toluene 4-monooxygenase, and toluene 2,3-dioxygenase. We found no significant differences in fractionation among the three enzymes for either compound. Aerobic degradation of c-DCE occurred with low fractionation producing δ13C enrichment factors of -0.9±0.5 to -1.2±0.5, in contrast to reported anaerobic degradation δ13C enrichment factors of -14.1‰ to -20.4‰. Aerobic degradation of TCE resulted in δ13C enrichment factors of -11.6±4.1‰ to -14.7±3.0‰ which overlap reported δ13C enrichment factors for anaerobic TCE degradation of -2.5‰ to -13.8‰. The data from this study suggest that stable isotopes could serve as a diagnostic for detecting aerobic biodegradation of TCE by toluene oxygenases at contaminated sites.

  14. Current State of Knowledge in Microbial Degradation of Polycyclic Aromatic Hydrocarbons (PAHs): A Review

    Science.gov (United States)

    Ghosal, Debajyoti; Ghosh, Shreya; Dutta, Tapan K.; Ahn, Youngho

    2016-01-01

    Polycyclic aromatic hydrocarbons (PAHs) include a group of organic priority pollutants of critical environmental and public health concern due to their toxic, genotoxic, mutagenic and/or carcinogenic properties and their ubiquitous occurrence as well as recalcitrance. The increased awareness of their various adverse effects on ecosystem and human health has led to a dramatic increase in research aimed toward removing PAHs from the environment. PAHs may undergo adsorption, volatilization, photolysis, and chemical oxidation, although transformation by microorganisms is the major neutralization process of PAH-contaminated sites in an ecologically accepted manner. Microbial degradation of PAHs depends on various environmental conditions, such as nutrients, number and kind of the microorganisms, nature as well as chemical property of the PAH being degraded. A wide variety of bacterial, fungal and algal species have the potential to degrade/transform PAHs, among which bacteria and fungi mediated degradation has been studied most extensively. In last few decades microbial community analysis, biochemical pathway for PAHs degradation, gene organization, enzyme system, genetic regulation for PAH degradation have been explored in great detail. Although, xenobiotic-degrading microorganisms have incredible potential to restore contaminated environments inexpensively yet effectively, but new advancements are required to make such microbes effective and more powerful in removing those compounds, which were once thought to be recalcitrant. Recent analytical chemistry and genetic engineering tools might help to improve the efficiency of degradation of PAHs by microorganisms, and minimize uncertainties of successful bioremediation. However, appropriate implementation of the potential of naturally occurring microorganisms for field bioremediation could be considerably enhanced by optimizing certain factors such as bioavailability, adsorption and mass transfer of PAHs. The main

  15. Current State of Knowledge in Microbial Degradation of Polycyclic Aromatic Hydrocarbons (PAHs): A Review.

    Science.gov (United States)

    Ghosal, Debajyoti; Ghosh, Shreya; Dutta, Tapan K; Ahn, Youngho

    2016-01-01

    Polycyclic aromatic hydrocarbons (PAHs) include a group of organic priority pollutants of critical environmental and public health concern due to their toxic, genotoxic, mutagenic and/or carcinogenic properties and their ubiquitous occurrence as well as recalcitrance. The increased awareness of their various adverse effects on ecosystem and human health has led to a dramatic increase in research aimed toward removing PAHs from the environment. PAHs may undergo adsorption, volatilization, photolysis, and chemical oxidation, although transformation by microorganisms is the major neutralization process of PAH-contaminated sites in an ecologically accepted manner. Microbial degradation of PAHs depends on various environmental conditions, such as nutrients, number and kind of the microorganisms, nature as well as chemical property of the PAH being degraded. A wide variety of bacterial, fungal and algal species have the potential to degrade/transform PAHs, among which bacteria and fungi mediated degradation has been studied most extensively. In last few decades microbial community analysis, biochemical pathway for PAHs degradation, gene organization, enzyme system, genetic regulation for PAH degradation have been explored in great detail. Although, xenobiotic-degrading microorganisms have incredible potential to restore contaminated environments inexpensively yet effectively, but new advancements are required to make such microbes effective and more powerful in removing those compounds, which were once thought to be recalcitrant. Recent analytical chemistry and genetic engineering tools might help to improve the efficiency of degradation of PAHs by microorganisms, and minimize uncertainties of successful bioremediation. However, appropriate implementation of the potential of naturally occurring microorganisms for field bioremediation could be considerably enhanced by optimizing certain factors such as bioavailability, adsorption and mass transfer of PAHs. The main

  16. Current State of Knowledge in Microbial Degradation of Polycyclic Aromatic Hydrocarbons (PAHs): A Review

    Science.gov (United States)

    Ghosal, Debajyoti; Ghosh, Shreya; Dutta, Tapan K.; Ahn, Youngho

    2016-01-01

    Polycyclic aromatic hydrocarbons (PAHs) include a group of organic priority pollutants of critical environmental and public health concern due to their toxic, genotoxic, mutagenic and/or carcinogenic properties and their ubiquitous occurrence as well as recalcitrance. The increased awareness of their various adverse effects on ecosystem and human health has led to a dramatic increase in research aimed toward removing PAHs from the environment. PAHs may undergo adsorption, volatilization, photolysis, and chemical oxidation, although transformation by microorganisms is the major neutralization process of PAH-contaminated sites in an ecologically accepted manner. Microbial degradation of PAHs depends on various environmental conditions, such as nutrients, number and kind of the microorganisms, nature as well as chemical property of the PAH being degraded. A wide variety of bacterial, fungal and algal species have the potential to degrade/transform PAHs, among which bacteria and fungi mediated degradation has been studied most extensively. In last few decades microbial community analysis, biochemical pathway for PAHs degradation, gene organization, enzyme system, genetic regulation for PAH degradation have been explored in great detail. Although, xenobiotic-degrading microorganisms have incredible potential to restore contaminated environments inexpensively yet effectively, but new advancements are required to make such microbes effective and more powerful in removing those compounds, which were once thought to be recalcitrant. Recent analytical chemistry and genetic engineering tools might help to improve the efficiency of degradation of PAHs by microorganisms, and minimize uncertainties of successful bioremediation. However, appropriate implementation of the potential of naturally occurring microorganisms for field bioremediation could be considerably enhanced by optimizing certain factors such as bioavailability, adsorption and mass transfer of PAHs. The main

  17. Current state of knowledge in microbial degradation of polycyclic aromatic hydrocarbons (PAHs: a review

    Directory of Open Access Journals (Sweden)

    Debajyoti Ghosal

    2016-08-01

    Full Text Available Polycyclic aromatic hydrocarbons (PAHs include a group of organic priority pollutants of critical environmental and public health concern due to their toxic, genotoxic, mutagenic and/or carcinogenic properties and their ubiquitous occurrence as well as recalcitrance. The increased awareness of their various adverse effects on ecosystem and human health has led to a dramatic increase in research aimed towards removing PAHs from the environment. PAHs may undergo adsorption, volatilization, photolysis, and chemical oxidation, although transformation by microorganisms is the major neutralization process of PAH-contaminated sites in an ecologically accepted manner. Microbial degradation of PAHs depends on various environmental conditions, such as nutrients, number and kind of the microorganisms, nature as well as chemical property of the PAH being degraded. A wide variety of bacterial, fungal and algal species have the potential to degrade/transform PAHs, among which bacteria and fungi mediated degradation has been studied most extensively. In last few decades microbial community analysis, biochemical pathway for PAHs degradation, gene organization, enzyme system, genetic regulation for PAH degradation have been explored in great detail. Although, xenobiotic-degrading microorganisms have incredible potential to restore contaminated environments inexpensively yet effectively, but new advancements are required to make such microbes effective and more powerful in removing those compounds, which were once thought to be recalcitrant. Recent analytical chemistry and genetic engineering tools might help to improve the efficiency of degradation of PAHs by microorganisms, and minimize uncertainties of successful bioremediation. However, appropriate implementation of the potential of naturally occurring microorganisms for field bioremediation could be considerably enhanced by optimizing certain factors such as bioavailability, adsorption and mass transfer of

  18. Current State of Knowledge in Microbial Degradation of Polycyclic Aromatic Hydrocarbons (PAHs): A Review.

    Science.gov (United States)

    Ghosal, Debajyoti; Ghosh, Shreya; Dutta, Tapan K; Ahn, Youngho

    2016-01-01

    Polycyclic aromatic hydrocarbons (PAHs) include a group of organic priority pollutants of critical environmental and public health concern due to their toxic, genotoxic, mutagenic and/or carcinogenic properties and their ubiquitous occurrence as well as recalcitrance. The increased awareness of their various adverse effects on ecosystem and human health has led to a dramatic increase in research aimed toward removing PAHs from the environment. PAHs may undergo adsorption, volatilization, photolysis, and chemical oxidation, although transformation by microorganisms is the major neutralization process of PAH-contaminated sites in an ecologically accepted manner. Microbial degradation of PAHs depends on various environmental conditions, such as nutrients, number and kind of the microorganisms, nature as well as chemical property of the PAH being degraded. A wide variety of bacterial, fungal and algal species have the potential to degrade/transform PAHs, among which bacteria and fungi mediated degradation has been studied most extensively. In last few decades microbial community analysis, biochemical pathway for PAHs degradation, gene organization, enzyme system, genetic regulation for PAH degradation have been explored in great detail. Although, xenobiotic-degrading microorganisms have incredible potential to restore contaminated environments inexpensively yet effectively, but new advancements are required to make such microbes effective and more powerful in removing those compounds, which were once thought to be recalcitrant. Recent analytical chemistry and genetic engineering tools might help to improve the efficiency of degradation of PAHs by microorganisms, and minimize uncertainties of successful bioremediation. However, appropriate implementation of the potential of naturally occurring microorganisms for field bioremediation could be considerably enhanced by optimizing certain factors such as bioavailability, adsorption and mass transfer of PAHs. The main

  19. Effects of prokaryotic diversity changes on hydrocarbon degradation rates and metal partitioning during bioremediation of contaminated anoxic marine sediments

    International Nuclear Information System (INIS)

    We investigated changes of prokaryotic diversity during bioremediation experiments carried out on anoxic marine sediments characterized by high hydrocarbon and metal content. Microcosms containing contaminated sediments were amended with lactose and acetate and incubated in anaerobic conditions up to 60 d at 20 or 35 °C. Microcosms displaying higher degradation efficiency of hydrocarbons were characterized by the dominance of Alphaproteobacteria and Methanosarcinales and the lack of gene sequences belonging to known hydrocarbonoclastic bacteria. Multivariate analyses support the hypothesis that Alphaproteobacteria are important for hydrocarbon degradation and highlight a potential synergistic effect of archaea and bacteria in changes of metal partitioning. Overall, these results point out that the identification of changes in the prokaryotic diversity during bioremediation of contaminated marine sediments is not only important for the improvement of bio-treatment performance towards hydrocarbons, but also for a better comprehension of changes occurring in metal partitioning which affect their mobility and toxicity.

  20. Enhanced photocatalytic activity of degrading short chain chlorinated paraffins over reduced graphene oxide/CoFe2O4/Ag nanocomposite.

    Science.gov (United States)

    Chen, Xin; Zhao, Qidong; Li, Xinyong; Wang, Dong

    2016-10-01

    Short chain chlorinated paraffins have recently attracted great attention because of their environmental persistence and biological toxicity as an important organic pollutant. In this work, reduced graphene oxide/CoFe2O4/Ag (RGO/CoFe2O4/Ag) nanocomposite was prepared and employed for photocatalytic degradation of short chain chlorinated paraffins. The process of photocatalytic degradation of short chain chlorinated paraffins over RGO/CoFe2O4/Ag under visible light (λ>400nm) was investigated by in situ Fourier transform infrared spectroscopy and the related mechanisms were proposed. An apparent degradation ratio of 91.9% over RGO/CoFe2O4/Ag could be obtained under visible light illumination of 12h, while only about 21.7% was obtained with commercial P25 TiO2 under the same experimental conditions, which demonstrates that the RGO/CoFe2O4/Ag nanocomposite is a potential candidate for effective photocatalytic removal of short chain chlorinated paraffins. PMID:27376973

  1. Microbial degradation of street dust polycyclic aromatic hydrocarbons in microcosms simulating diffuse pollution of urban soil.

    Science.gov (United States)

    Johnsen, Anders R; de Lipthay, Julia R; Sørensen, Søren J; Ekelund, Flemming; Christensen, Peter; Andersen, Ole; Karlson, Ulrich; Jacobsen, Carsten S

    2006-03-01

    Diffuse pollution with polycyclic aromatic hydrocarbons (PAHs) of topsoil in urban regions has caused increasing concerns in recent years. We simulated diffuse pollution of soil in microcosms by spiking sandy topsoil (A-horizon) and coarse, mineral subsoil (C-horizon) with street dust (PM63) isolated from municipal street sweepings from central Copenhagen. The microbial communities adapted to PAH degradation in microcosms spiked with street dust in both A-horizon and C-horizon soils, in spite of low PAH-concentrations. The increased potential for PAH degradation was demonstrated on several levels: by slowly diminishing PAH-concentrations, increased mineralization of 14C-PAHs, increasing numbers of PAH degraders and increased prevalence of nah and pdo1 PAH degradation genes, i.e. the microbial communities quickly adapted to PAH degradation. Three- and 4-ring PAHs from the street dust were biodegraded to some extent (10-20%), but 5- and 6-ring PAHs were not biodegraded in spite of frequent soil mixing and high PAH degradation potentials. In addition to biodegradation, leaching of 2-, 3- and 4-ring PAHs from the A-horizon to the C-horizon seems to reduce PAH-levels in surface soil. Over time, levels of 2-, 3- and 4-ring PAHs in surface soil may reach equilibrium between input and the combination of biodegradation and leaching. However, levels of the environmentally critical 5- and 6-ring PAHs will probably continue to rise. We presume that sorption to black carbon particles is responsible for the persistence and low bioaccessibility of 5- and 6-ring PAHs in diffusely polluted soil.

  2. Microbial diversity and anaerobic hydrocarbon degradation potential in an oil-contaminated mangrove sediment

    Directory of Open Access Journals (Sweden)

    Andrade Luiza L

    2012-08-01

    Full Text Available Abstract Background Mangrove forests are coastal wetlands that provide vital ecosystem services and serve as barriers against natural disasters like tsunamis, hurricanes and tropical storms. Mangroves harbour a large diversity of organisms, including microorganisms with important roles in nutrient cycling and availability. Due to tidal influence, mangroves are sites where crude oil from spills farther away can accumulate. The relationship between mangrove bacterial diversity and oil degradation in mangrove sediments remains poorly understood. Results Mangrove sediment was sampled from 0–5, 15–20 and 35–40 cm depth intervals from the Suruí River mangrove (Rio de Janeiro, Brazil, which has a history of oil contamination. DGGE fingerprinting for bamA, dsr and 16S rRNA encoding fragment genes, and qPCR analysis using dsr and 16S rRNA gene fragment revealed differences with sediment depth. Conclusions Analysis of bacterial 16S rRNA gene diversity revealed changes with depth. DGGE for bamA and dsr genes shows that the anaerobic hydrocarbon-degrading community profile also changed between 5 and 15 cm depth, and is similar in the two deeper sediments, indicating that below 15 cm the anaerobic hydrocarbon-degrading community appears to be well established and homogeneous in this mangrove sediment. qPCR analysis revealed differences with sediment depth, with general bacterial abundance in the top layer (0–5 cm being greater than in both deeper sediment layers (15–20 and 35–40 cm, which were similar to each other.

  3. Biodegradation of used lubricating engine oil contaminated water using indigenous hydrocarbon degrading microbes in a fixed bed bioreactor system

    International Nuclear Information System (INIS)

    The performance of a mixed population of hydrocarbon-degrading microbes in removing hydro-carbon contaminant in water was investigated using a fixed bed bioreactor system. The hydrocarbon-degrading microbes used for the study were isolated from oil-contaminated soil and further cultured in a nutrient medium. Sample concentrations of 500 mg/L, 1000 mg/L, 2000 mg/L and 6000 mg/L were studied. Each sample concentration was studied at loading rates of 0.5 L/min, 1.0 L/min, and 2.0 L/min for a week. Total petroleum hydrocarbon (TPH), pH, temperature, dissolved oxygen (DO), conductivity and the microbial population density were measured to ascertain the progress of microbial degradation of the oil contaminant in the water. A minimum degradation rate of 36. 83 ± 0.00% was achieved at the least administered loading rate of 0.5 L/min at 1000 mg/L oil concentration. Maximum degradation rate of 93.85 ± 0.00% was also achieved at loading rate of 1.0 L/min at the highest oil concentration of 6000 mg/L. The minimum and maximum degradation rates were achieved at microbial populations of 1. 53E + 13 ± 0.00 and 1.50E+13 ± 0.00, respectively. The hydrocarbon degradation occurred in an optimum pH range of 6.63 ± 0.20 and 7.32 ± 0.11 and a temperature range of 27.3 ± 0. 76 and 29.9 ± 0.41 degrees celsius. (au)

  4. Role of nutrients and illuminance in predicting the fate of fungal mediated petroleum hydrocarbon degradation and biomass production.

    Science.gov (United States)

    Ali Khan, Aqib Hassan; Tanveer, Sundus; Anees, Mariam; Muhammad, Yousaf Shad; Iqbal, Mazhar; Yousaf, Sohail

    2016-07-01

    Biodegradation and biomass production are affected by numerous environmental factors including pH, oxygen availability and presence of pollutants. The present study, for the first time, elucidated the effects of nutrients and light on mycodegradation of petroleum hydrocarbons in diesel oil. Seven fungal strains (Aspergillus terreus FA3, Aspergillus niger FA5, Aspergillus terreus FA6, Penicillium chrysogenum FP4, Aspergillus terreus FP6, Aspergillus flavus FP10, and Candida sp. FG1) were used for hydrocarbon degradation under static conditions, in four combinations of nutrient media and illuminance for 45 days. Highest degradation was achieved by Aspergillus terreus FA6 and Candida sp. FG1 under both conditions of light and dark, with nutrient deprived HAF (Hydrocarbon adopted fungi) broth. Under HAF/Dark diesel oil degradation by FA6 and FG1 was 87.3% and 84.3% respectively, while under HAF/Light both FA6 and FG1 performed 84.3% biodegradation. The highest biomass was produced by Aspergillus flavus FP10 in PDB (Potato dextrose broth)/Dark (109.3 mg). Fungal degradation of petroleum hydrocarbons was negatively affected by the presence of other simpler-to-degrade carbon sources in the medium. The biomass production was enhanced by improved nutrient availability and diminished by illuminance. PMID:27039364

  5. Cold Incineration of Chlorophenols in Aqueous Solution by Advanced Electrochemical Process Electro-Fenton. Effect of Number and Position of Chlorine Atoms on the Degradation Kinetics

    Science.gov (United States)

    Oturan, Nihal; Panizza, Marco; Oturan, Mehmet A.

    2009-09-01

    This study reports the kinetics of the degradation of several chlorophenols (CPs), such as monochlorophenols (2-chlorophenol and 4-chlorophenol), dichlorophenols (2,4-dichlorophenol and 2,6- dichlorophenol), trichlorophenols (2,3,5- trichlorophenol and 2,4,5-trichlorophenol), 2,3,5,6-tetrachlorophenol, and pentachlorophenol, by the electro-Fenton process using a carbon felt cathode and a Pt anode. The effect of number and the position of the chlorine atoms in the aromatic ring on the oxidative degradation rate was evaluated and discussed. The oxidation reaction of all the CPs with hydroxyl radicals evidenced a pseudo-first-order kinetics and the rate constant decreased with increasing the number of chlorine atoms. The absolute rate constant of second-order reaction kinetics between CPs and •OH was determined by the competition kinetics method in the range of (3.56-7.75) × 109 M-1 s-1 and follows the same sequence of the apparent rate constants. The mineralization of several CPs and of a mixture of all CPs under study was monitored by the total organic carbon (TOC) removal and the chlorine release during mineralization was followed by ion chromatography. Our results demonstrated that more chlorinated phenols are more difficult to mineralize; however for all the tested CPs, almost quantitative release of chloride ions was obtained after 6 h of treatment.

  6. Engineering of a silica encapsulation platform for hydrocarbon degradation using Pseudomonas sp. NCIB 9816-4.

    Science.gov (United States)

    Sakkos, Jonathan K; Kieffer, Daniel P; Mutlu, Baris R; Wackett, Lawrence P; Aksan, Alptekin

    2016-03-01

    Industrial application of encapsulated bacteria for biodegradation of hydrocarbons in water requires mechanically stable materials. A silica gel encapsulation method was optimized for Pseudomonas sp. NCIB 9816-4, a bacterium that degrades more than 100 aromatic hydrocarbons. The design process focused on three aspects: (i) mechanical property enhancement; (ii) gel cytocompatibility; and (iii) reduction of the diffusion barrier in the gel. Mechanical testing indicated that the compressive strength at failure (σf ) and elastic modulus (E) changed linearly with the amount of silicon alkoxide used in the gel composition. Measurement of naphthalene biodegradation by encapsulated cells indicated that the gel maintained cytocompatibility at lower levels of alkoxide. However, significant loss in activity was observed due to methanol formation during hydrolysis at high alkoxide concentrations, as measured by FTIR spectroscopy. The silica gel with the highest amount of alkoxide (without toxicity from methanol) had a biodegradation rate of 285 ± 42 nmol/L-s, σf  = 652 ± 88 kPa, and E = 15.8 ± 2.0 MPa. Biodegradation was sustained for 1 month before it dropped below 20% of the initial rate. In order to improve the diffusion through the gel, polyvinyl alcohol (PVA) was used as a porogen and resulted in a 48 ± 19% enhancement in biodegradation, but it impacted the mechanical properties negatively. This is the first report studying how the silica composition affects biodegradation of naphthalene by Pseudomonas sp. NCIB 9816-4 and establishes a foundation for future studies of aromatic hydrocarbon biodegradation for industrial application. PMID:26332745

  7. Implications of treating water containing polynuclear aromatic hydrocarbons with chlorine: a gas chromatographic-mass spectrometric study.

    OpenAIRE

    Oyler, A R; Liukkonen, R J; Lukasewycz, M K; Cox, D A; Peake, D A; Carlson, R M

    1982-01-01

    The products of aqueous chlorination reactions of 1-methylnaphthalene, fluorene, dibenzofuran, anthracene, phenanthrene, 1-methylphenanthrene, fluoranthene, and pyrene have been determined. The conditions employed for these reactions approximated those that might be encountered in water treatment facilities. Reactions at pH greater than 6 tended to produce oxygenated products (epoxides, phenols, quinones, etc.), and reactions at pH less than 6 tended to produce both oxygenated (quinones) and ...

  8. Generalist hydrocarbon-degrading bacterial communities in the oil-polluted water column of the North Sea

    NARCIS (Netherlands)

    Chronopoulou, P.M.; Sanni, G.O.; Silas-Olu, D.I.; van der Meer, J.R.; Timmis, K.N.; Brussaard, C.P.D.; McGenity, T.J.

    2015-01-01

    The aim of this work was to determine the effect of light crude oil on bacterial communities during an experimental oil spill in the North Sea and in mesocosms (simulating a heavy, enclosed oil spill), and to isolate and characterize hydrocarbon-degrading bacteria from the water column. No oil-induc

  9. Characteristics of Newly Isolated Geobacillus sp. ZY-10 Degrading Hydrocarbons in Crude Oil.

    Science.gov (United States)

    Sun, Yumei; Ning, Zhanguo; Yang, Fan; Li, Xianzhen

    2015-01-01

    An obligately thermophilic strain ZY-10 was isolated from the crude oil in a high-temperature oilfield, which was capable of degrading heavy crude oil. Phenotypic and phylogenetic analysis demonstrated that the isolate should be grouped in the genus Geobacillus, which shared thd highest similarity (99%) of the 16S rDNA sequence to Geobacillus stearothermophilus. However, the major cellular fatty acid iso-15:0 (28.55%), iso-16:0 (24.93%), iso-17:0 (23.53%) and the characteristics including indole production, tolerance to NaN3 and carbohydrate fermentation showed some difference from the recognized species in the genus Geobacillus. The isolate could use tridecane, hexadecane, octacosane and hexatridecane as sole carbon source for cell growth, and the digesting rate of long-chain alkane was lower than that of short-chain alkane. When the isolate was cultured in the heavy crude oil supplement with inorganic salts and trace yeast extract, the concentration of short-chain alkane was significantly increased and the content of long-chain alkane was decreased, suggesting that the larger hydrocarbon components in crude oil were degraded into shorter-chain alkane. Strain ZY-10 would be useful for improving the mobility of crude oil and upgrading heavy crude oil in situ.

  10. Degradation of phenolics, nitrogen-heterocyclics and polynuclear aromatic hydrocarbons in a rotating biological contactor.

    Science.gov (United States)

    Jeswani, Hansa; Mukherji, Suparna

    2012-05-01

    The degradation of phenolics, heterocyclics and polynuclear aromatic hydrocarbons (PAHs) in a synthetic biomass gasifier wastewater with average COD of 1388 mg/L was studied in a three stage rotating biological contactor (RBC) using the pyrene degrader, Exiguobacterium aurantiacum and activated sludge consortia (1:3 v/v). As the organic loading rate (OLR) was varied from 3.3 to 14 g/m(2)/d, the COD removal ranged from 63.3% to 92.6%. Complete removal of all the constituents was observed at the lowest OLR of 3.3g/m(2)/d. At 24h hydraulic retention time (HRT) and OLR of 6.6g/m(2)/d complete removal of pyridine, quinoline and benzene and 85-96% removal of phenol, naphthalene, phenanthrene, fluoranthene and pyrene was observed. E. aurantiacum was found to be the dominant bacteria in the biofilm. Clark's model provided good fits to data for all the three stages of the RBC.

  11. Potential of Polycyclic Aromatic Hydrocarbon-Degrading Bacterial Isolates to Contribute to Soil Fertility

    Directory of Open Access Journals (Sweden)

    Maryam Bello-Akinosho

    2016-01-01

    Full Text Available Restoration of polycyclic aromatic hydrocarbon- (PAH- polluted sites is presently a major challenge in agroforestry. Consequently, microorganisms with PAH-degradation ability and soil fertility improvement attributes are sought after in order to achieve sustainable remediation of polluted sites. This study isolated PAH-degrading bacteria from enriched cultures of spent automobile engine-oil polluted soil. Isolates’ partial 16S rRNA genes were sequenced and taxonomically classified. Isolates were further screened for their soil fertility attributes such as phosphate solubilization, atmospheric nitrogen fixation, and indoleacetic acid (IAA production. A total of 44 isolates were obtained and belong to the genera Acinetobacter, Arthrobacter, Bacillus, Flavobacterium, Microbacterium, Ochrobactrum, Pseudomonas, Pseudoxanthomonas, Rhodococcus, and Stenotrophomonas. Data analysed by principal component analysis showed the Bacillus and Ochrobactrum isolates displayed outstanding IAA production. Generalized linear modelling statistical approaches were applied to evaluate the contribution of the four most represented genera (Pseudomonas, Acinetobacter, Arthrobacter, and Rhodococcus to soil fertility. The Pseudomonas isolates were the most promising in all three soil fertility enhancement traits evaluated and all isolates showed potential for one or more of the attributes evaluated. These findings demonstrate a clear potential of the isolates to participate in restorative bioremediation of polluted soil, which will enhance sustainable agricultural production and environmental protection.

  12. Potential of Polycyclic Aromatic Hydrocarbon-Degrading Bacterial Isolates to Contribute to Soil Fertility

    Science.gov (United States)

    Chirima, George Johannes

    2016-01-01

    Restoration of polycyclic aromatic hydrocarbon- (PAH-) polluted sites is presently a major challenge in agroforestry. Consequently, microorganisms with PAH-degradation ability and soil fertility improvement attributes are sought after in order to achieve sustainable remediation of polluted sites. This study isolated PAH-degrading bacteria from enriched cultures of spent automobile engine-oil polluted soil. Isolates' partial 16S rRNA genes were sequenced and taxonomically classified. Isolates were further screened for their soil fertility attributes such as phosphate solubilization, atmospheric nitrogen fixation, and indoleacetic acid (IAA) production. A total of 44 isolates were obtained and belong to the genera Acinetobacter, Arthrobacter, Bacillus, Flavobacterium, Microbacterium, Ochrobactrum, Pseudomonas, Pseudoxanthomonas, Rhodococcus, and Stenotrophomonas. Data analysed by principal component analysis showed the Bacillus and Ochrobactrum isolates displayed outstanding IAA production. Generalized linear modelling statistical approaches were applied to evaluate the contribution of the four most represented genera (Pseudomonas, Acinetobacter, Arthrobacter, and Rhodococcus) to soil fertility. The Pseudomonas isolates were the most promising in all three soil fertility enhancement traits evaluated and all isolates showed potential for one or more of the attributes evaluated. These findings demonstrate a clear potential of the isolates to participate in restorative bioremediation of polluted soil, which will enhance sustainable agricultural production and environmental protection. PMID:27774456

  13. Reactive transport modeling of chemical and isotope data to identify degradation processes of chlorinated ethenes in a diffusion-dominated media

    DEFF Research Database (Denmark)

    Chambon, Julie Claire Claudia; Damgaard, Ida; Jeannottat, Simon;

    zones in the low-permeability media. Previous studies have shown that degradation might be limited to high permeability zones in clay tills, thus limiting the applicability of remediation strategies based on enhanced biodegradation. Therefore the occurrence of degradation inside the clay matrix......Chlorinated ethenes are among the most widespread contaminants in the subsurface and a major threat to groundwater quality at numerous contaminated sites. Many of these contaminated sites are found in low-permeability media, such as clay tills, where contaminant transport is controlled by diffusion...

  14. Degradation of polycyclic aromatic hydrocarbons by free and nanoclay-immobilized manganese peroxidase from Anthracophyllum discolor.

    Science.gov (United States)

    Acevedo, F; Pizzul, L; Castillo, M Dp; González, M E; Cea, M; Gianfreda, L; Diez, M C

    2010-06-01

    Manganese peroxidase (MnP) produced by Anthracophyllum discolor, a Chilean white rot fungus, was immobilized on nanoclay obtained from volcanic soil and its ability to degrade polycyclic aromatic hydrocarbons (PAHs) compared with the free enzyme was evaluated. At the same time, nanoclay characterization was performed. Nanoclay characterization by transmission electronic microscopy showed a particle average size smaller than 100 nm. The isoelectric points (IEP) of nanoclay and MnP from A. discolor were 7.0 and 3.7, respectively, as determined by micro electrophoresis migration and preparative isoelectric focusing. Results indicated that 75% of the enzyme was immobilized on the nanoclay through physical adsorption. As compared to the free enzyme, immobilized MnP from A. discolor achieved an improved stability to temperature and pH. The activation energy (Ea) value for immobilized MnP (51.9 kJ mol(-1)) was higher than that of the free MnP (34.4 kJ mol(-1)). The immobilized enzyme was able to degrade pyrene (>86%), anthracene (>65%), alone or in mixture, and to a less extent fluoranthene (soil. Overall results indicate that nanoclay, a carrier of natural origin, is a suitable support material for MnP immobilization. In addition, immobilized MnP shows an increased stability to high temperature, pH and time storage, as well as an enhanced PAHs degradation efficiency in soil. All these characteristics may suggest the possible use of nanoclay-immobilized MnP from A. discolor as a valuable option for in situ bioremediation purposes. PMID:20435332

  15. The polycyclic aromatic hydrocarbon degradation potential of Gulf of Mexico coastal microbial communities after the Deepwater Horizon oil spill

    Directory of Open Access Journals (Sweden)

    Anthony D. Kappell

    2014-05-01

    Full Text Available The Deepwater Horizon (DWH blowout resulted in oil transport, including polycyclic aromatic hydrocarbons (PAHs to the Gulf of Mexico shoreline. The microbial communities of these shorelines are thought to be responsible for the intrinsic degradation of PAHs. To investigate the Gulf Coast beach microbial community response to hydrocarbon exposure, we examined the functional gene diversity, bacterial community composition, and PAH degradation capacity of a heavily oiled and non-oiled beach following the oil exposure. With a non-expression functional gene microarray targeting 539 gene families, we detected 28,748 coding sequences. Of these sequences, 10% were uniquely associated with the severely oil-contaminated beach and 6.0% with the non-oiled beach. There was little variation in the functional genes detected between the two beaches; however the relative abundance of functional genes involved in oil degradation pathways, including PAHs, were greater in the oiled beach. The microbial PAH degradation potentials of both beaches, were tested in mesocosms. Mesocosms were constructed in glass columns using sands with native microbial communities, circulated with artificial sea water and challenged with a mixture of PAHs. The low-molecular weight PAHs, fluorene and naphthalene, showed rapid depletion in all mesocosms while the high-molecular weight benzo[α]pyrene was not degraded by either microbial community. Both the heavily oiled and the non-impacted coastal communities showed little variation in their biodegradation ability for low molecular weight PAHs. Massively-parallel sequencing of 16S rRNA genes from mesocosm DNA showed that known PAH degraders and genera frequently associated with oil hydrocarbon degradation represented a major portion of the bacterial community. The observed similar response by microbial communities from beaches with a different recent history of oil exposure suggests that Gulf Coast beach communities are primed for PAH

  16. Screening and Optimization of Bio surfactant Production by the Hydrocarbon-Degrading Bacteria

    International Nuclear Information System (INIS)

    Bio surfactants are amphiphilic compounds produced by microorganisms as secondary metabolite. The unique properties of bio surfactants make them possible to replace or to be added to synthetic surfactants which are mainly used in food, cosmetics and pharmaceutical industries and in environmental applications. In this study twenty hydrocarbon-degrading bacteria were screened for bio surfactant production. All of the bacterial isolates were grown in mineral salt medium (MSM) with addition of 1 % (v/v) Tapis crude oil as carbon source. The presence of bio surfactant was determined by the drop-collapse test, microplate analysis, oil spreading technique, emulsification index (%EI24) and surface tension measurement. Only one isolate, Pseudomonas aeruginosa UKMP14T, was found to be positive for all the qualitative tests and reducing the surface tension of the medium to 49.5 dynes/ with emulsification index of 25.29 %. This isolate produced bio surfactant optimally at pH 9.0 and incubation temperature of 37 degree Celsius. Furthermore, P. aeruginosa UKMP14T when grown in MSM with addition of 1 % (v/v) glycerol and 1.3 g/ L ammonium sulphate with C/N ratio 14:1 produced bio surfactant with percentage of surface tension reduction at 55 % or 30.6 dynes/ cm with %EI24 of 43 %. This percentage of surface tension reduction represents an increasing reduction in surface tension of medium by 39 % over the value before optimization. This study showed that P. aeruginosa UKMP14T has the ability to biodegrade hydrocarbon and concurrently produce bio surfactant. (author)

  17. Aquatic Organisms and Petroleum Hydrocarbon Degrading Bacteria Associated with Their Digestive System

    Directory of Open Access Journals (Sweden)

    Janina Šyvokienė

    2014-01-01

    Full Text Available Laboratory investigation was carried out on the abundance and composition of bacteria in the digestive system of a total of 35 specimens, including bivalve molluscs, i.e. swan mussel Anodonta cygnea (Linnaeus, 1758 from Lake Spėra (Širvintos district and swollen river mussel Unio tumidus (Philipson, 1788 from the Curonian Lagoon near Juodkrantė, zebra mussel (Dreissena polymorpha from the Curonian Lagoon near Juodkrantė and an anostracan – Chirocephalus josephinae (Grube, 1853 from a pond in Ilčiukai village, Utena district, and in the water of related water bodies. Studies on bivalve molluscs (swan mussel and swollen river mussel, zebra mussel and an anostracan – Chirocephalus josephinae, as well as microbiological investigation of water demonstrated that the number of microorganisms in the digestive system of mollusc and anostracan species fluctuated and varied between different species and water bodies. The greatest percentage of HDB among total heterotrophic bacteria was found in the digestive system of swollen river mussels (21.53% and in zebra mussels (19.99% caught in the Curonian Lagoon and in the water of the lagoon (24%. A considerably smaller percentage of HDB was detected in the digestive system of swan mussels from Lake Spėra (17.6% and in the water of the lake (16.66%. The smallest percentage of HDB was found in the digestive system of Chirocephalus josephinae (6.63% and in the water of the Ilčiukai pond (2.72%. According to the values of abundance of petroleum hydrocarbon-degrading bacteria (HDB and total coliform bacteria (TCFB in the digestive system of aquatic organisms we can state that the water ecosystem of Ilčiukai pond was the least contaminated with petroleum, its products and sewage water, and the Curonian Lagoon water ecosystem was the most contaminated. Abundance of petroleum hydrocarbons degrading bacteria could be used as a bioindicator reflecting the level of ecosystem pollution petroleum and its

  18. Aquatic Organisms and Petroleum Hydrocarbon Degrading Bacteria Associated with Their Digestive System

    Directory of Open Access Journals (Sweden)

    Janina Šyvokienė

    2013-12-01

    Full Text Available Laboratory investigation was carried out on the abundance and composition of bacteria in the digestive system of a total of 35 specimens, including bivalve molluscs, i.e. swan mussel Anodonta cygnea (Linnaeus, 1758 from Lake Spėra (Širvintos district and swollen river mussel Unio tumidus (Philipson, 1788 from the Curonian Lagoon near Juodkrantė, zebra mussel (Dreissena polymorpha from the Curonian Lagoon near Juodkrantė and an anostracan – Chirocephalus josephinae (Grube, 1853 from a pond in Ilčiukai village, Utena district, and in the water of related water bodies. Studies on bivalve molluscs (swan mussel and swollen river mussel, zebra mussel and an anostracan – Chirocephalus josephinae, as well as microbiological investigation of water demonstrated that the number of microorganisms in the digestive system of mollusc and anostracan species fluctuated and varied between different species and water bodies. The greatest percentage of HDB among total heterotrophic bacteria was found in the digestive system of swollen river mussels (21.53% and in zebra mussels (19.99% caught in the Curonian Lagoon and in the water of the lagoon (24%. A considerably smaller percentage of HDB was detected in the digestive system of swan mussels from Lake Spėra (17.6% and in the water of the lake (16.66%. The smallest percentage of HDB was found in the digestive system of Chirocephalus josephinae (6.63% and in the water of the Ilčiukai pond (2.72%. According to the values of abundance of petroleum hydrocarbon-degrading bacteria (HDB and total coliform bacteria (TCFB in the digestive system of aquatic organisms we can state that the water ecosystem of Ilčiukai pond was the least contaminated with petroleum, its products and sewage water, and the Curonian Lagoon water ecosystem was the most contaminated. Abundance of petroleum hydrocarbons degrading bacteria could be used as a bioindicator reflecting the level of ecosystem pollution petroleum and its

  19. Chlorinated hydrocarbons in livers of American mink (Mustela vison) and river otter (Lutra canadensis) from the Columbia and Fraser River Basins, 1990-1992

    Science.gov (United States)

    Elliott, J.E.; Henny, Charles J.; Harris, M.L.; Wilson, L.K.; Norstrom, R.J.

    1999-01-01

    We investigated chlorinated hydrocarbon contaminants in aquatic mustelid species on the Fraser and Columbia Rivers of northwestern North America. Carcasses of river otter (Lutra canadensis) (N=24) and mink (Mustela vison) (N=34) were obtained from commercial trappers during the winters of 1990-91 and 1991a??92. Pooled liver samples were analyzed for organochlorine pesticides, polychlorinated biphenyls (PCBs), including non-ortho congeners, polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). Most samples contained detectable concentrations of DDE, PCBs, although there was substantial variability in patterns and trends among neighboring samples. Concentrations of DDE were in some mink and several otter samples from the lower Columbia River elevated (to 4700 g/kg wet weight); excluding one mink sample from the Wenatchee area, mean DDE levels generally decreased between 1978a??79 and 1990a??92. PCBs were present in all samples. PCB concentrations in otter livers collected from the lower Columbia were ten-fold lower than measured a decade previously; nevertheless, a sample taken near Portland had a mean concentration of 1500 g/kg, within a range of concentrations associated with reproductive effects in captive mink. Concentrations of 2,3,7,8-TCDD and TCDF were generally below detection limits, except for one otter collected near a pulp mill at Castlegar, on the upper Columbia, with 11 ng TCDD/kg in liver. Elevated concentrations of higher chlorinated PCDD/Fs, probably resulting from use of chlorophenolic wood preservatives, were found in both species; one otter sample from the lower Columbia had 2200 ng OCDD/kg. International TCDD toxic equivalent levels in mink (31 ng/kg) and otter (93 ng/kg) from the lower Columbia River approached toxicity thresholds for effects on reproduction in ranch mink.

  20. Effects of soil organic matter on the development of the microbial polycyclic aromatic hydrocarbons (PAHs) degradation potentials

    International Nuclear Information System (INIS)

    The microbial activity in soils was a critical factor governing the degradation of organic micro-pollutants. The present study was conducted to analyze the effects of soil organic matter on the development of degradation potentials for polycyclic aromatic hydrocarbons (PAHs). Most of the degradation kinetics for PAHs by the indigenous microorganisms developed in soils can be fitted with the Logistic growth models. The microbial activities were relatively lower in the soils with the lowest and highest organic matter content, which were likely due to the nutrition limit and PAH sequestration. The microbial activities developed in humic acid (HA) were much higher than those developed in humin, which was demonstrated to be able to sequester organic pollutants stronger. The results suggested that the nutrition support and sequestration were the two major mechanisms, that soil organic matter influenced the development of microbial PAHs degradation potentials. - Research highlights: → PAH degradation kinetics obey Logistic model. → Degradation potentials depend on soil organic carbon content. → Humin inhibits the development of PAH degradation activity. → Nutrition support and sequestration regulate microbial degradation capacity. - Soil organic matter regulated PAH degradation potentials through nutrition support and sequestration.

  1. ASSESSMENT OF PETROLEUM HYDROCARBON DEGRADATION FROM SOIL AND TARBALL BY FUNGI

    Directory of Open Access Journals (Sweden)

    Sakineh Lotfinasabasl1, V. R.Gunale1, N. S. Rajurkar 1, 2

    2012-06-01

    Full Text Available Four fungi strains viz. Aspergillus niger, Aspergillus terreus, Rhizopus sp and Penicillium sp were isolated from soil and tarball samples collected from mangrove forest of Alibaug and Akshi coastal area, Maharashtra, India. These strains were assessed for their degradation capability of petroleum hydrocarbons measuring growth diameter in Potato Dextrose Agar (PDA solid media for different concentrations of kerosene (5%- 20% (v/v. Rhizopus sp showed the highest growth diameter in 5% kerosene and Aspergillus niger showed the highest growth diameter in 20% kerosene while, penicillium sp showed the lowest growth diameter at all the concentrations of kerosene as compared to other three strains. The bioremediation of 20% oil contaminated soil by different fungi strains was found in the order Aspergillus niger> Rhizopus sp> Aspergillus terreus > Penicillium sp. In order to determine the effect of mixed fungal culture in contrast with single one, studies were carried out in 10% (v/v oil contaminated PDA media. It was observed that a mix culture consisting of penicillium sp, Rhizopus sp and Aspergillus terreus showed highest growth diameter.

  2. Prediction of mono- and polycyclic aromatic hydrocarbon degradation in spiked soils using cyclodextrin extraction

    International Nuclear Information System (INIS)

    In this study, an aqueous-based hydroxypropyl-β-cyclodextrin (HPCD) extraction technique was assessed for its capacity to determine the microbially degradable fraction of mono- and polycyclic aromatic hydrocarbons in four dissimilar soils. A linear relationship (slope = 0.90; R 2 = 0.89), approaching 1:1 between predicted and observed phenanthrene mineralization, was demonstrated for the cyclodextrin extraction; however, the water only extraction underestimated the microbially available fraction by a factor of three (slope = 3.35; R 2 = 0.64). With respect to determining the mineralizable fraction of p-cresol in soils, the cyclodextrin extraction (slope = 0.94; R 2 = 0.84) was more appropriate than the water extraction (slope = 1.50; R 2 = 0.36). Collectively, these results suggested that the cyclodextrin extraction technique was suitable for the prediction of the mineralizable fraction of representative PAHs and phenols present in dissimilar soils following increasing soil-contaminant contact times. The assessment of the microbial availability of contaminants in soils is important for a more representative evaluation of soil contamination. - An aqueous-based HPCD extraction technique was more appropriate than the water extraction in prediction of the mineralizable fraction of phenanthrene and p-cresol present in a range of dissimilar soils

  3. Reactive Transport Modeling of Chemical and Isotope Data to Identify Degradation Processes of Chlorinated Ethenes in a Diffusion-Dominated Media

    Science.gov (United States)

    Chambon, J. C.; Damgaard, I.; Jeannottat, S.; Hunkeler, D.; Broholm, M. M.; Binning, P. J.; Bjerg, P. L.

    2012-12-01

    Chlorinated ethenes are among the most widespread contaminants in the subsurface and a major threat to groundwater quality at numerous contaminated sites. Many of these contaminated sites are found in low-permeability media, such as clay tills, where contaminant transport is controlled by diffusion. Degradation and transport processes of chlorinated ethenes are not well understood in such geological settings, therefore risk assessment and remediation at these sites are particularly challenging. In this work, a combined approach of chemical and isotope analysis on core samples, and reactive transport modeling has been used to identify the degradation processes occurring at the core scale. The field data was from a site located at Vadsby, Denmark, where chlorinated solvents were spilled during the 1960-70's, resulting in contamination of the clay till and the underlying sandy layer (15 meters below surface). The clay till is heavily contaminated between 4 and 15 mbs, both with the mother compounds PCE/TCE and TCA and the daughter products (DCE, VC, ethene, DCA), indicating the occurrence of natural dechlorination of both PCE/TCE and TCA. Intact core samples of length 0.5m were collected from the source zone (between 6 and 12 mbs). Concentrations and stable isotope ratios of the mother compounds and their daughter products, as well as redox parameters, fatty acids and microbial data, were analyzed with discrete sub-sampling along the cores. More samples (each 5 mm) were collected around the observed higher permeability zones such as sand lenses, sand stringers and fractures, where a higher degradation activity was expected. This study made use of a reactive transport model to investigate the appropriateness of several conceptual models. The conceptual models considered the location of dechlorination and degradation pathways (biotic reductive dechlorination or abiotic β-elimination with iron minerals) in three core profiles. The model includes diffusion in the matrix

  4. A quantitative PCR approach for quantification of functional genes involved in the degradation of polycyclic aromatic hydrocarbons in contaminated soils

    Science.gov (United States)

    Shahsavari, Esmaeil; Aburto-Medina, Arturo; Taha, Mohamed; Ball, Andrew S.

    2016-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are major pollutants globally and due to their carcinogenic and mutagenic properties their clean-up is paramount. Bioremediation or using PAH degrading microorganisms (mainly bacteria) to degrade the pollutants represents cheap, effective methods. These PAH degraders harbor functional genes which help microorganisms use PAHs as source of food and energy. Most probable number (MPN) and plate counting methods are widely used for counting PAHs degraders; however, as culture based methods only count a small fraction (soil samples.•This protocol enables us to screen a vast number of PAH contaminated soil samples in few hours.•This protocol provides valuable information about the natural attenuation potential of contaminated soil and can be used to monitor the bioremediation process. PMID:27054096

  5. Cultivation-dependent and cultivation-independent characterisation of hydrocarbon-degrading bacteria in Guaymas Basin sediments

    Directory of Open Access Journals (Sweden)

    Tony eGutierrez

    2015-07-01

    Full Text Available Marine hydrocarbon-degrading bacteria perform a fundamental role in the biodegradation of crude oil and its petrochemical derivatives in coastal and open ocean environments. However, there is a paucity of knowledge on the diversity and function of these organisms in deep-sea sediment. Here we used stable-isotope probing (SIP, a valuable tool to link the phylogeny and function of targeted microbial groups, to investigate polycyclic aromatic hydrocarbon (PAH-degrading bacteria under aerobic conditions in sediments from Guaymas Basin with uniformly labeled [13C]phenanthrene. The dominant sequences in clone libraries constructed from 13C-enriched bacterial DNA (from phenanthrene enrichments were identified to belong to the genus Cycloclasticus. We used quantitative PCR primers targeting the 16S rRNA gene of the SIP-identified Cycloclasticus to determine their abundance in sediment incubations amended with unlabeled phenanthrene and showed substantial increases in gene abundance during the experiments. We also isolated a strain, BG-2, representing the SIP-identified Cycloclasticus sequence (99.9% 16S rRNA gene sequence identity, and used this strain to provide direct evidence of phenanthrene degradation and mineralization. In addition, we isolated Halomonas, Thalassospira and Lutibacterium spp. with demonstrable phenanthrene-degrading capacity from Guaymas Basin sediment. This study demonstrates the value of coupling SIP with cultivation methods to identify and expand on the known diversity of PAH-degrading bacteria in the deep-sea.

  6. Cultivation-dependent and cultivation-independent characterization of hydrocarbon-degrading bacteria in Guaymas Basin sediments.

    Science.gov (United States)

    Gutierrez, Tony; Biddle, Jennifer F; Teske, Andreas; Aitken, Michael D

    2015-01-01

    Marine hydrocarbon-degrading bacteria perform a fundamental role in the biodegradation of crude oil and its petrochemical derivatives in coastal and open ocean environments. However, there is a paucity of knowledge on the diversity and function of these organisms in deep-sea sediment. Here we used stable-isotope probing (SIP), a valuable tool to link the phylogeny and function of targeted microbial groups, to investigate polycyclic aromatic hydrocarbon (PAH)-degrading bacteria under aerobic conditions in sediments from Guaymas Basin with uniformly labeled [(13)C]-phenanthrene (PHE). The dominant sequences in clone libraries constructed from (13)C-enriched bacterial DNA (from PHE enrichments) were identified to belong to the genus Cycloclasticus. We used quantitative PCR primers targeting the 16S rRNA gene of the SIP-identified Cycloclasticus to determine their abundance in sediment incubations amended with unlabeled PHE and showed substantial increases in gene abundance during the experiments. We also isolated a strain, BG-2, representing the SIP-identified Cycloclasticus sequence (99.9% 16S rRNA gene sequence identity), and used this strain to provide direct evidence of PHE degradation and mineralization. In addition, we isolated Halomonas, Thalassospira, and Lutibacterium sp. with demonstrable PHE-degrading capacity from Guaymas Basin sediment. This study demonstrates the value of coupling SIP with cultivation methods to identify and expand on the known diversity of PAH-degrading bacteria in the deep-sea. PMID:26217326

  7. Assessing the hydrocarbon degrading potential of indigenous bacteria isolated from crude oil tank bottom sludge and hydrocarbon-contaminated soil of Azzawiya oil refinery, Libya.

    Science.gov (United States)

    Mansur, Abdulatif A; Adetutu, Eric M; Kadali, Krishna K; Morrison, Paul D; Nurulita, Yuana; Ball, Andrew S

    2014-09-01

    The disposal of hazardous crude oil tank bottom sludge (COTBS) represents a significant waste management burden for South Mediterranean countries. Currently, the application of biological systems (bioremediation) for the treatment of COTBS is not widely practiced in these countries. Therefore, this study aims to develop the potential for bioremediation in this region through assessment of the abilities of indigenous hydrocarbonoclastic microorganisms from Libyan Hamada COTBS for the biotreatment of Libyan COTBS-contaminated environments. Bacteria were isolated from COTBS, COTBS-contaminated soil, treated COTBS-contaminated soil, and uncontaminated soil using Bushnell Hass medium amended with Hamada crude oil (1 %) as the main carbon source. Overall, 49 bacterial phenotypes were detected, and their individual abilities to degrade Hamada crude and selected COBTS fractions (naphthalene, phenanthrene, eicosane, octadecane and hexane) were evaluated using MT2 Biolog plates. Analyses using average well colour development showed that ~90 % of bacterial isolates were capable of utilizing representative aromatic fractions compared to 51 % utilization of representative aliphatics. Interestingly, more hydrocarbonoclastic isolates were obtained from treated contaminated soils (42.9 %) than from COTBS (26.5 %) or COTBS-contaminated (30.6 %) and control (0 %) soils. Hierarchical cluster analysis (HCA) separated the isolates into two clusters with microorganisms in cluster 2 being 1.7- to 5-fold better at hydrocarbon degradation than those in cluster 1. Cluster 2 isolates belonged to the putative hydrocarbon-degrading genera; Pseudomonas, Bacillus, Arthrobacter and Brevundimonas with 57 % of these isolates being obtained from treated COTBS-contaminated soil. Overall, this study demonstrates that the potential for PAH degradation exists for the bioremediation of Hamada COTBS-contaminated environments in Libya. This represents the first report on the isolation of

  8. 水中氯代烃单体碳同位素分析中预富集方法进展%Review on Pre-enrichment Methods in Compound Specific Carbon Isotope Analysis of Chlorinated Hydrocarbon in Water

    Institute of Scientific and Technical Information of China (English)

    凌媛; 黄毅; 尚文郁; 谢曼曼; 刘舒波; 孙青

    2011-01-01

    Highly accurate determination of Compound Specific Carbon Isotope Analysis ( CSIA ) of chlorinated hydrocarbons is of great significance in tracing the source and revealing the biodegradating progress of pollutants. The isotopic composition of organic contaminations may be stable or varied in the process of environmental transformation. We can trace the source of contaminations if the composition is stable and can evaluate the probability and degree of degradation of contaminations. This paper summarizes solid-phase microextraction, static headspace analysis, purge and trap method and compound specific isotope analyses of chlorinated hydrocarbon in water, using combinations of these pretreatment methods, Gas Chromatography-Combustion-Isotope Ratio Mass Spectrometry ( GC-C-IRMS ), and comparesthe three methods. Compared with liquid-liquid extraction, solid-phase micro extraction, static headspace analysis, purge and trap method are all solvent-free enrichment techniques, producing no secondary pollution, less interference, and the resolution and accuracy of the analysis of GC-C-IRMS is improved. No, or little, isotopic mass fractionation occurred during the isotope analysis of chlorinated hydrocarbon in water by combining these solvent-free enrichment techniques with GC-C-IRMS, of which the precision of the analysis is less than l%e. The detection limit decreased along with the methods of static headspace analysis, solid-phase micro extraction, purge and trap method. Purge and trap is the most popular method because of its good reproducibility and low detection limit for the compound specific isotope analysis of chlorinated hydrocarbon in Water. The combinations of in-needle microextraction, in-tube microextraction, stir bar sorptive extraction or headspace sorptive extraction with GC-C-IRMS have a bright future.%高精度准确测定氯代烃单体碳同位素对示踪污染物来源,了解污染物的生物降解过程具有重要意义.在环境转化过程中,

  9. Different behavioral effect dose–response profiles in mice exposed to two-carbon chlorinated hydrocarbons: Influence of structural and physical properties

    Energy Technology Data Exchange (ETDEWEB)

    Umezu, Toyoshi, E-mail: umechan2@nies.go.jp; Shibata, Yasuyuki, E-mail: yshibata@nies.go.jp

    2014-09-01

    The present study aimed to clarify whether dose–response profiles of acute behavioral effects of 1,2-dichloroethane (DCE), 1,1,1-trichloroethane (TCE), trichloroethylene (TRIC), and tetrachloroethylene (PERC) differ. A test battery involving 6 behavioral endpoints was applied to evaluate the effects of DCE, TCE, TRIC, and PERC in male ICR strain mice under the same experimental conditions. The behavioral effect dose–response profiles of these compounds differed. Regression analysis was used to evaluate the relationship between the dose–response profiles and structural and physical properties of the compounds. Dose–response profile differences correlated significantly with differences in specific structural and physical properties. These results suggest that differences in specific structural and physical properties of DCE, TCE, TRIC, and PERC are responsible for differences in behavioral effects that lead to a variety of dose–response profiles. - Highlights: • We examine effects of 4 chlorinated hydrocarbons on 6 behavioral endpoints in mice. • The behavioral effect dose–response profiles for the 4 compounds are different. • We utilize regression analysis to clarify probable causes of the different profiles. • The compound's physicochemical properties probably produce the different profiles.

  10. Low-concentration tailing and subsequent quicklime-enhanced remediation of volatile chlorinated hydrocarbon-contaminated soils by mechanical soil aeration.

    Science.gov (United States)

    Ma, Yan; Du, Xiaoming; Shi, Yi; Xu, Zhu; Fang, Jidun; Li, Zheng; Li, Fasheng

    2015-02-01

    Mechanical soil aeration has long been regarded as an effective ex-situ remediation technique and as suitable for remediation of large-scale sites contaminated by volatile organic compounds (VOCs) at low cost. However, it has been reported that the removal efficiency of VOCs from soil is relatively low in the late stages of remediation, in association with tailing. Tailing may extend the remediation time required; moreover, it typically results in the presence of contaminants residues at levels far exceeding regulations. In this context, the present study aimed to discuss the tailing that occurs during the process of remediation of soils contaminated artificially with volatile chlorinated hydrocarbons (VCHs) and to assess possible quicklime-enhanced removal mechanisms. The results revealed the following conclusions. First, temperature and aeration rate can be important controls on both the timing of appearance of tailing and the levels of residual contaminants. Furthermore, the addition of quicklime to soil during tailing can reduce the residual concentrations rapidly to below the remedial target values required for site remediation. Finally, mechanical soil aeration can be enhanced using quicklime, which can improve the volatilization of VCHs via increasing soil temperature, reducing soil moisture, and enhancing soil permeability. Our findings give a basic understanding to the elimination of the tailing in the application of mechanical soil aeration, particularly for VOCs-contaminated soils.

  11. Isolation and Characterization of Hydrocarbon-Degrading Yeast Strains from Petroleum Contaminated Industrial Wastewater

    OpenAIRE

    Boutheina Gargouri; Najla Mhiri; Fatma Karray; Fathi Aloui; Sami Sayadi

    2015-01-01

    Two yeast strains are enriched and isolated from industrial refinery wastewater. These strains were observed for their ability to utilize several classes of petroleum hydrocarbons substrates, such as n-alkanes and aromatic hydrocarbons as a sole carbon source. Phylogenetic analysis based on the D1/D2 variable domain and the ITS-region sequences indicated that strains HC1 and HC4 were members of the genera Candida and Trichosporon, respectively. The mechanism of hydrocarbon uptaking by yeast, ...

  12. Use of dual carbon-chlorine isotope analysis to assess the degradation pathways of 1,1,1-trichloroethane in groundwater.

    Science.gov (United States)

    Palau, Jordi; Jamin, Pierre; Badin, Alice; Vanhecke, Nicolas; Haerens, Bruno; Brouyère, Serge; Hunkeler, Daniel

    2016-04-01

    Compound-specific isotope analysis (CSIA) is a powerful tool to track contaminant fate in groundwater. However, the application of CSIA to chlorinated ethanes has received little attention so far. These compounds are toxic and prevalent groundwater contaminants of environmental concern. The high susceptibility of chlorinated ethanes like 1,1,1-trichloroethane (1,1,1-TCA) to be transformed via different competing pathways (biotic and abiotic) complicates the assessment of their fate in the subsurface. In this study, the use of a dual C-Cl isotope approach to identify the active degradation pathways of 1,1,1-TCA is evaluated for the first time in an aerobic aquifer impacted by 1,1,1-TCA and trichloroethylene (TCE) with concentrations of up to 20 mg/L and 3.4 mg/L, respectively. The reaction-specific dual carbon-chlorine (C-Cl) isotope trends determined in a recent laboratory study illustrated the potential of a dual isotope approach to identify contaminant degradation pathways of 1,1,1-TCA. Compared to the dual isotope slopes (Δδ(13)C/Δδ(37)Cl) previously determined in the laboratory for dehydrohalogenation/hydrolysis (DH/HY, 0.33 ± 0.04) and oxidation by persulfate (∞), the slope determined from field samples (0.6 ± 0.2, r(2) = 0.75) is closer to the one observed for DH/HY, pointing to DH/HY as the predominant degradation pathway of 1,1,1-TCA in the aquifer. The observed deviation could be explained by a minor contribution of additional degradation processes. This result, along with the little degradation of TCE determined from isotope measurements, confirmed that 1,1,1-TCA is the main source of the 1,1-dichlorethylene (1,1-DCE) detected in the aquifer with concentrations of up to 10 mg/L. This study demonstrates that a dual C-Cl isotope approach can strongly improve the qualitative and quantitative assessment of 1,1,1-TCA degradation processes in the field. PMID:26874254

  13. Polynuclear aromatic hydrocarbon degradation by heterogeneous reactions with N 2O 5 on atmospheric particles

    Science.gov (United States)

    Kamens, Richard M.; Guo, Jiazhen; Guo, Zhishi; McDow, Stephen R.

    The degradation of particulate polynuclear aromatic hydrocarbons (PAH) on atmospheric soot particles in the presence of gas phase dinitrogen pentoxide (N 2O 5) was explored. Dilute diesel and wood soot particles containing PAH were reacted with˜10ppm of N 2O 5 in a 200 ℓ continuous stirred tank reactor (CSTR). To provide a stable source of particles for reaction in the CSTR, diesel or wood soot particles were injected at night into a 25 m 3 Teflon outdoor chamber. The large chamber served as a reservoir for the feed aerosol, and the aerosol could then be introduced at a constant flow rate into the CSTR. PAH-N 2O 5 heterogeneous rate constants for wood soot at 15°C ranged from2 × 10 -18to5 × 10 -18 cm 3 molecules -1 s -1. For diesel soot the rate constants at 16°C were higher and ranged from5 × 10 -18to30 × 10 -18 cm 3 molecules -1 s -1. Comparisons with other studies suggest that sunlight is the most important factor which influences PAH decay. This is followed by ozone, NO 2, N 2O 5 and nitric acid. The rate constants of nitro-PAH formation from a parent PAH and N 2O 5 were of the order of1 × 10 -19-1 × 10 -18 molecules -1s -1. The uncertainty associated with all of these rate constants is± a factor of 3. Given, however, the small magnitude of the rate constants and the low levels of N 2O 5 present in the atmosphere, we concluded that PAH heterogeneous reactions with gas phase N 2O 5 degrade particle-bound PAH or to form nitro-PAH from PAH are not very important. (Direct application of the specific rate constants derived in this study to ambient atmospheres should not be undertaken unless the ambient particle size distributions and chemical composition of the particles are similar to the ones reported in this study.)

  14. Photocatalytic degradation of oil industry hydrocarbons models at laboratory and at pilot-plant scale

    Energy Technology Data Exchange (ETDEWEB)

    Vargas, Ronald; Nunez, Oswaldo [Laboratorio de Fisicoquimica Organica y Quimica Ambiental, Departamento de Procesos y Sistemas, Universidad Simon Bolivar, Apartado Postal 89000, Caracas (Venezuela)

    2010-02-15

    Photodegradation/mineralization (TiO{sub 2}/UV Light) of the hydrocarbons: p-nitrophenol (PNP), naphthalene (NP) and dibenzothiophene (DBT) at three different reactors: batch bench reactor (BBR), tubular bench reactor (TBR) and tubular pilot-plant (TPP) were kinetically monitored at pH = 3, 6 and 10, and the results compared using normalized UV light exposition times. The results fit the Langmuir-Hinshelwood (LH) model; therefore, LH adsorption equilibrium constants (K) and apparent rate constants (k) are reported as well as the apparent pseudo-first-order rate constants, k{sub obs}{sup '} = kK/(1 + Kc{sub r}). The batch bench reactor is the most selective reactor toward compound and pH changes in which the reactivity order is: NP > DBT > PNP, however, the catalyst adsorption (K) order is: DBT > NP > PNP at the three pH used but NP has the highest k values. The tubular pilot-plant (TPP) is the most efficient of the three reactors tested. Compound and pH photodegradation/mineralization selectivity is partially lost at the pilot plant where DBT and NP reaches ca. 90% mineralization at the pH used, meanwhile, PNP reaches only 40%. The real time, in which these mineralization occur are: 180 min for PNP and 60 min for NP and DBT. The mineralization results at the TPP indicate that for the three compounds, the rate limiting step is the same as the degradation one. So that, there is not any stable intermediate that may accumulate during the photocatalytic treatment. (author)

  15. Microbial and molecular techniques to evaluate and to implement in-situ biodegradation potential and activity at sites contaminated with aromatic and chlorinated hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Karg, F. [HPC Envirotec / France and HPC AG (Germany); Henkler, Ch. [Planreal (Switzerland)

    2005-07-01

    Intrinsic bio-remediation harnesses the ability of indigenous microorganisms to degrade contaminants that are present in soil and groundwater. Over the past decade many environmental regulatory agencies especially in Europe have come to recognize the importance of these natural processes in contaminant attenuation. In order to use in-situ bio-remediation to clean up a site successfully it is necessary to investigate the indigenous microbial population and its potential activity to degrade the contaminants of concern (COCs). The evaluation of naturally-occurring degradative activity in initial screening of soil and groundwater samples using recently developed molecular and microbial methods may allow for the implementation of a contaminant reduction and management program without the need for fully engineered remediation intervention. Limited engineering approaches (nutrient delivery etc.) can be implemented to support naturally-occurring bio-restoration processes to achieve a controlled, dynamic attenuation of COCs. Techniques for monitoring pollutant-degrading microorganisms were previously limited to standard culturing techniques. More recently, techniques based upon detection of genetic elements and metabolic activities have been developed in collaboration with university partners Europe, especially in France. The modern techniques are more sensitive for monitoring microbial populations, metabolic activity and the genetic potential to degrade the COCs, and avoid the need for cultivation of microbes under artificial conditions in the laboratory. Especially the application of PCR-Tests (Polymerase Chain Reaction) are able to quantify the Genetic Potential of Pollutant Microbiological Degradation on a contaminated site. This enables to use very economic in-situ site rehabilitation strategies as for example (Dynamic Natural Attenuation). For this modern application of these new strategies PLANREAL created with HPC Envirotec and together with a French University

  16. Photocatalytic degradation of polycyclic aromatic hydrocarbons on soil surfaces using TiO2 under UV light

    International Nuclear Information System (INIS)

    The photocatalytic degradation of phenanthrene (PHE), pyrene (PYRE) and benzo[a]pyrene (BaP) on soil surfaces in the presence of TiO2 using ultraviolet (UV) light source was investigated in a photo chamber, in which the temperature was maintained 30 deg. C. The effects of various factors, namely TiO2, soil pH, humic acid, and UV wavelength, on the degradation performance of polycyclic aromatic hydrocarbons (PAHs) were studied. The results show that photocatalytic degradation of PAHs follows the pseudo-first-order kinetics. Catalyst TiO2 accelerated the photodegradation of PHE, PYRE and BaP significantly, with their half-lives being reduced from 533.15 to 130.77 h, 630.09 to 192.53 h and 363.22 to 103.26 h, respectively, when the TiO2 content was 0.5%. In acidic or alkaline conditions, the photocatalytic degradation rates of the PAHs were greater than those in neutral conditions. Humic acid significantly enhanced the PAH photocatalytic degradation by sensitizing radicals capable of oxidizing PAHs. Photocatalytic degradation rates of PYRE and BaP on soil surfaces with 2% TiO2 were different at UV irradiation wavelengths of 254, 310 and 365 nm, respectively. The synergistic effect of UV irradiation and TiO2 catalysis was efficient for degradation of PAHs in contaminated soil

  17. Degradation of polycyclic aromatic hydrocarbons in crumb tyre rubber catalysed by rutile TiO2 under UV irradiation.

    Science.gov (United States)

    Yu, Kai; Huang, Linyue; Lou, Lan-Lan; Chang, Yue; Dong, Yanling; Wang, Huan; Liu, Shuangxi

    2015-01-01

    The polycyclic aromatic hydrocarbons (PAHs) in crumb tyre rubber were firstly degraded under UV irradiation in the presence of rutile TiO2 and hydrogen peroxide. The effects of light intensity, catalyst amount, oxidant amount, initial pH value, co-solvent content, and reaction time on degradation efficiency of typical PAHs in crumb tyre rubber were studied. The results indicated that UV irradiation, rutile TiO2, and hydrogen peroxide were beneficial to the degradation of PAHs and co-solvent could accelerate the desorption of PAHs from crumb tyre rubber. Up to 90% degradation efficiency of total 16 PAHs could be obtained in the presence of rutile TiO2 (1 wt%) and hydrogen peroxide (1.0 mL) under 1800 µW cm(-2) UV irradiation for 48 h. The high molecular weight PAHs (such as benz(a)pyrene) were more difficult to be degraded than low molecular weight PAHs (such as phenanthrene, chrysene). Moreover, through the characterization of reaction solution and degradation products via GC-MS, it was proved that the PAHs in crumb tyre rubber were successfully degraded. PMID:25323028

  18. Determination of the hydrocarbon-degrading metabolic capabilities of tropical bacterial isolates

    Energy Technology Data Exchange (ETDEWEB)

    Marquez-Rocha, F.J.; Olmos-Soto, J. [Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, San Diego, CA (United States). Departamento de Biotecnologia Marina; Rosano-Hernandez, M.A.; Muriel-Garcia, M. [Instituto Mexicano del Petroleo, CD Carmen Camp (Mexico). Zona Marina/Tecnologia Ambiental

    2005-01-01

    Of more than 20 bacteria isolated from a tropical soil using minimal medium supplemented with hydrocarbons, 11 grew well on diesel as sole carbon source, and another 11 grew in the presence of polynuclear aromatic hydrocarbons (PAHs). Ten isolates were identified phenotypically as Pseudomonas sp. and eight as Bacillus sp. Gene sequences representing the catabolic genes (alkM, todM, ndoM, and xylM) and 16S rRNA gene sequences characteristic for Pseudomona and Bacillus were amplified by PCR, using DNA recovered from the supernatant of hydrocarbon-contaminated soil suspensions. Based on their rapid growth characteristics in the presence of hydrocarbons and the formation of PCR products for the catabolic genes alkM and ndoM six isolates were selected for biodegradation assays. After 30 days a mixed culture of two isolates achieved close to 70% hydrocarbon removal and apparent mineralization of 16% of the hydrocarbons present in the soil. Biodegradation rates varied from 275 to 387 mg hydrocarbon kg{sup -1} day{sup -1}. Several bacterial isolates obtained in this study have catabolic capabilities for the biodegradation of alkanes and aromatic hydrocarbons including PAHs. (author)

  19. EDTA addition enhances bacterial respiration activities and hydrocarbon degradation in bioaugmented and non-bioaugmented oil-contaminated desert soils.

    Science.gov (United States)

    Al Kharusi, Samiha; Abed, Raeid M M; Dobretsov, Sergey

    2016-03-01

    The low number and activity of hydrocarbon-degrading bacteria and the low solubility and availability of hydrocarbons hamper bioremediation of oil-contaminated soils in arid deserts, thus bioremediation treatments that circumvent these limitations are required. We tested the effect of Ethylenediaminetetraacetic acid (EDTA) addition, at different concentrations (i.e. 0.1, 1 and 10 mM), on bacterial respiration and biodegradation of Arabian light oil in bioaugmented (i.e. with the addition of exogenous alkane-degrading consortium) and non-bioaugmented oil-contaminated desert soils. Post-treatment shifts in the soils' bacterial community structure were monitored using MiSeq sequencing. Bacterial respiration, indicated by the amount of evolved CO2, was highest at 10 mM EDTA in bioaugmented and non-bioaugmented soils, reaching an amount of 2.2 ± 0.08 and 1.6 ± 0.02 mg-CO2 g(-1) after 14 days of incubation, respectively. GC-MS revealed that 91.5% of the C14-C30 alkanes were degraded after 42 days when 10 mM EDTA and the bacterial consortium were added together. MiSeq sequencing showed that 78-91% of retrieved sequences in the original soil belonged to Deinococci, Alphaproteobacteria, Gammaproteobacteia and Bacilli. The same bacterial classes were detected in the 10 mM EDTA-treated soils, however with slight differences in their relative abundances. In the bioaugmented soils, only Alcanivorax sp. MH3 and Parvibaculum sp. MH21 from the exogenous bacterial consortium could survive until the end of the experiment. We conclude that the addition of EDTA at appropriate concentrations could facilitate biodegradation processes by increasing hydrocarbon availability to microbes. The addition of exogenous oil-degrading bacteria along with EDTA could serve as an ideal solution for the decontamination of oil-contaminated desert soils.

  20. Strong Impact on the Polycyclic Aromatic Hydrocarbon (PAH)-Degrading Community of a PAH-Polluted Soil but Marginal Effect on PAH Degradation when Priming with Bioremediated Soil Dominated by Mycobacteria▿

    OpenAIRE

    Johnsen, Anders R.; Schmidt, Stine; Hybholt, Trine K.; Henriksen, Sidsel; Jacobsen, Carsten S.; Andersen, Ole

    2007-01-01

    Bioaugmentation of soil polluted with polycyclic aromatic hydrocarbons (PAHs) is often disappointing because of the low survival rate and low activity of the introduced degrader bacteria. We therefore investigated the possibility of priming PAH degradation in soil by adding 2% of bioremediated soil with a high capacity for PAH degradation. The culturable PAH-degrading community of the bioremediated primer soil was dominated by Mycobacterium spp. A microcosm containing pristine soil artificial...

  1. Chlorinated and parent polycyclic aromatic hydrocarbons in environmental samples from an electronic waste recycling facility and a chemical industrial complex in China.

    Science.gov (United States)

    Ma, Jing; Horii, Yuichi; Cheng, Jinping; Wang, Wenhua; Wu, Qian; Ohura, Takeshi; Kannan, Kurunthachalam

    2009-02-01

    Chlorinated polycyclic aromatic hydrocarbons (CIPAHs) are a class of halogenated contaminants found in the urban atmosphere; they have toxic potential similar to that of dioxins. Information on the sources of CIPAHs is limited. In this study, concentrations of 20 CIPAHs and 16 parent PAHs were measured in electronic wastes, workshop-floor dust, vegetation, and surface soil collected from the vicinity of an electronic waste (e-waste) recycling facility and in surface soil from a chemical industrial complex (comprising a coke-oven plant, a coal-fired power plant, and a chlor-alkali plant), and agricultural areas in central and eastern China. High concentrations of SigmaCIPAHs were found in floor dust (mean, 103 ng/g dry wt), followed in order of decreasing concentration by leaves (87.5 ng/g drywt), electronic shredder waste (59.1 ng/g dry wt), and soil (26.8 ng/g dry wt) from an e-waste recycling facility in Taizhou. The mean concentration of SigmaCIPAHs in soil from the chemical industrial complex (88 ng/g dry wt) was approximately 3-fold higher than the concentration in soil from e-waste recycling facilities. The soils from e-waste sites and industrial areas contained mean concentrations of SigmaCIPAHs 2 to 3 orders of magnitude higher than the concentrations in agricultural soils (ND-0.76 ng/g), suggesting that e-waste recycling and chlorine-chemical industries are potential emission sources of CIPAHs. The profiles of CIPAHs in soil and dust were similar to a profile that has been reported previously for fly ash from municipal solid waste incinerators (6-CIBaP was the predominant compound), but the profiles in vegetation and electronic shredder waste were different from those found in fly ash. Concentrations of 16 parent PAHs were high (150-49,700 ng/g) in samples collected from the e-waste recycling facility. Significant correlation between SigmaCIPAH and SigmaPAH concentrations suggests that direct chlorination of parent PAHs is the major pathway of formation of

  2. Genomic insights into the metabolic potential of the polycyclic aromatic hydrocarbon degrading sulfate-reducing Deltaproteobacterium N47.

    Science.gov (United States)

    Bergmann, Franz; Selesi, Draženka; Weinmaier, Thomas; Tischler, Patrick; Rattei, Thomas; Meckenstock, Rainer U

    2011-05-01

    Anaerobic degradation of polycyclic aromatic hydrocarbons (PAHs) is an important process during natural attenuation of aromatic hydrocarbon spills. However, knowledge about metabolic potential and physiology of organisms involved in anaerobic degradation of PAHs is scarce. Therefore, we introduce the first genome of the sulfate-reducing Deltaproteobacterium N47 able to catabolize naphthalene, 2-methylnaphthalene, or 2-naphthoic acid as sole carbon source. Based on proteomics, we analysed metabolic pathways during growth on PAHs to gain physiological insights on anaerobic PAH degradation. The genomic assembly and taxonomic binning resulted in 17 contigs covering most of the sulfate reducer N47 genome according to general cluster of orthologous groups (COGs) analyses. According to the genes present, the Deltaproteobacterium N47 can potentially grow with the following sugars including d-mannose, d-fructose, d-galactose, α-d-glucose-1P, starch, glycogen, peptidoglycan and possesses the prerequisites for butanoic acid fermentation. Despite the inability for culture N47 to utilize NO(3) (-) as terminal electron acceptor, genes for nitrate ammonification are present. Furthermore, it is the first sequenced genome containing a complete TCA cycle along with the carbon monoxide dehydrogenase pathway. The genome contained a significant percentage of repetitive sequences and transposase-related protein domains enhancing the ability of genome evolution. Likewise, the sulfate reducer N47 genome contained many unique putative genes with unknown function, which are candidates for yet-unknown metabolic pathways.

  3. Assessing the correlation between anaerobic toluene degradation activity and bssA concentrations in hydrocarbon-contaminated aquifer material.

    Science.gov (United States)

    Kazy, Sufia K; Monier, Amy L; Alvarez, Pedro J J

    2010-09-01

    The assessment of biodegradation activity in contaminated aquifers is critical to demonstrate the performance of bioremediation and natural attenuation and to parameterize models of contaminant plume dynamics. Real time quantitative PCR (qPCR) was used to target the catabolic bssA gene (coding for benzylsuccinate synthase) and a 16S rDNA phylogenetic gene (for total Bacteria) as potential biomarkers to infer on anaerobic toluene degradation rates. A significant correlation (P = 0.0003) was found over a wide range of initial toluene concentrations (1-100 mg/l) between toluene degradation rates and bssA concentrations in anaerobic microcosms prepared with aquifer material from a hydrocarbon contaminated site. In contrast, the correlation between toluene degradation activity and total Bacteria concentrations was not significant (P = 0.1125). This suggests that qPCR targeting of functional genes might offer a simple approach to estimate in situ biodegradation activity, which would enhance site investigation and modeling of natural attenuation at hydrocarbon-contaminated sites. PMID:20204467

  4. Complete Genome Sequence of Bacillus pumilus PDSLzg-1, a Hydrocarbon-Degrading Bacterium Isolated from Oil-Contaminated Soil in China

    Science.gov (United States)

    Hao, Kun; Li, Hongna; Li, Feng

    2016-01-01

    Bacillus pumilus strain PDSLzg-1, an efficient hydrocarbon-degrading bacterium, was isolated from oil-contaminated soil. Here, we present the complete sequence of its circular chromosome and circular plasmid. The genomic information is essential for the study of degradation of oil by B. pumilus PDSLzg-1.

  5. Site profiles of low-volatile chlorinated hydrocarbons - cause-oriented monitoring in aquatic media. Vol.2. Low-volatile chlorinated hydrocarbons in surface water, sediments, suspended matter and fish of the Elbe river and its tributaries; Standortprofile schwerfluechtiger chlorierter Kohlenwasserstoffe (SCKW) - ursachenorientiertes Monitoring in aquatischen Medien. Bd. 2. SCKW in Oberflaechenwasser, Sediment, Schwebstoffen und Fischen aus der Elbe und Nebenfluessen

    Energy Technology Data Exchange (ETDEWEB)

    Heinisch, E.; Kettrup, A.; Gebefuegi, I.; Martens, D.; Bergheim, W.; Wenzel, S.

    2001-07-01

    Evaluating the primary data from ARGE ELBE, LAU Halle/Saale and the Environmental Specimen Banking (Umweltprobenbank) as well from publications from the Czech Republic (CHMU) the concentrations of the following low volatile chlorinated hydrocarbons were established for surface water, sediment, breams and eels from the rivers Elbe, Schwarze Elster, Mulde and Saale partly from 1989 till 1999: DDT and its metabolites DDE and DDD, partly as 2,4'- and 4,4' isomers; HCH ({alpha}-, {beta}-, {gamma}- and {delta} isomers); chlorinated benzenes with 1-6 Cl atoms and octachlorostyrene. The data evaluated were drawn up into tables - comprehensive in a separate supplement, in short versions within the text - and consolidated into graphs. Aim of the paper was a cause-oriented monitoring. The by far most important emission sources, found from the distance and time profiles as well as from special assessments of the substance patterns, were chemical plants. (orig.) [German] Durch Auswertung von Primaerdaten der ARGE ELBE, des LAU Halle/Saale und der Umweltprobenbank sowie von Publikationen aus Tschechien (CHMU) wurden fuer Oberflaechenwasser, Sediment, Brassen/Bleien und Aale aus der Elbe, Schwarzen Elster, Mulde und Saale fuer die Jahre von z.T. 1989 bis 1999 die Konzentrationen der folgenden schwerfluechtigen Kohlenwasserstoffe (SCKW) ermittelt: DDT und seine Metabolite DDE und DDD, z.T. als 2,4'- und 4,4'-Isomere; HCH ({alpha}-, {beta}-, {gamma}- und {delta}-Isomere); chlorierte Benzole mit 1-6 Cl-Atomen und Octachlorstyrol. Die ausgewerteten Daten wurden zu Tabellen - ausfuehrlich in einem gesonderten Tabellenanhang und verkuerzt im Textteil - zusammengestellt sowie zu Grafiken verdichtet. Ziel der Arbeit war ein ursachenorientiertes Monitoring. Als mit Abstand wesentlichste Emissionsquellen konnten anhand von Streckenprofilen und Zeitrastern sowie durch spezielle Auswertungen der Stoffmusterverteilungen Chemibetriebe ermittelt werden. (orig.)

  6. Variability of Biological Degradation of Phenolic Hydrocarbons in an Aerobic Aquifer Determined by Laboratory Batch Experiments

    DEFF Research Database (Denmark)

    Nielsen, Per Henning; Christensen, Thomas Højlund

    1994-01-01

    and groundwater from 8 localities representing a 15 m × 30 m section of an aerobic aquifer. Three patterns of variation were found: (1) phenol, o-cresol and in most cases p-nitrophenol showed very fast degradation with no or only short lag phases and with very little variation among localities; (2) 2......,4-dichlorophenol was degraded in all localities and showed large variability among localities with respect to lag phases (0–50 days) and some variation with respect to degradation periods (20–40 days); and (3) nitrobenzene, o-nitrophenol, 2,6-dichlorophenol and 4,6-o-dichlorocresol showed very large variability...... among localities ranging from no degradation within 149 days in some localities to degradation within 2 days in other localities. The degradation patterns were highly sequential, indicating a general sequence, for those compounds degradable, valid in all localities. The results are of importance...

  7. Microbial diversity and hydrocarbon degrading gene capacity of a crude oil field soil as determined by metagenomics analysis.

    Science.gov (United States)

    Abbasian, Firouz; Palanisami, Thavamani; Megharaj, Mallavarapu; Naidu, Ravi; Lockington, Robin; Ramadass, Kavitha

    2016-05-01

    Soils contaminated with crude oil are rich sources of enzymes suitable for both degradation of hydrocarbons through bioremediation processes and improvement of crude oil during its refining steps. Due to the long term selection, crude oil fields are unique environments for the identification of microorganisms with the ability to produce these enzymes. In this metagenomic study, based on Hiseq Illumina sequencing of samples obtained from a crude oil field and analysis of data on MG-RAST, Actinomycetales (9.8%) were found to be the dominant microorganisms, followed by Rhizobiales (3.3%). Furthermore, several functional genes were found in this study, mostly belong to Actinobacteria (12.35%), which have a role in the metabolism of aliphatic and aromatic hydrocarbons (2.51%), desulfurization (0.03%), element shortage (5.6%), and resistance to heavy metals (1.1%). This information will be useful for assisting in the application of microorganisms in the removal of hydrocarbon contamination and/or for improving the quality of crude oil. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:638-648, 2016. PMID:26914145

  8. Microbial diversity and hydrocarbon degrading gene capacity of a crude oil field soil as determined by metagenomics analysis.

    Science.gov (United States)

    Abbasian, Firouz; Palanisami, Thavamani; Megharaj, Mallavarapu; Naidu, Ravi; Lockington, Robin; Ramadass, Kavitha

    2016-05-01

    Soils contaminated with crude oil are rich sources of enzymes suitable for both degradation of hydrocarbons through bioremediation processes and improvement of crude oil during its refining steps. Due to the long term selection, crude oil fields are unique environments for the identification of microorganisms with the ability to produce these enzymes. In this metagenomic study, based on Hiseq Illumina sequencing of samples obtained from a crude oil field and analysis of data on MG-RAST, Actinomycetales (9.8%) were found to be the dominant microorganisms, followed by Rhizobiales (3.3%). Furthermore, several functional genes were found in this study, mostly belong to Actinobacteria (12.35%), which have a role in the metabolism of aliphatic and aromatic hydrocarbons (2.51%), desulfurization (0.03%), element shortage (5.6%), and resistance to heavy metals (1.1%). This information will be useful for assisting in the application of microorganisms in the removal of hydrocarbon contamination and/or for improving the quality of crude oil. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:638-648, 2016.

  9. Candidates for the development of consortia capable of petroleum hydrocarbon degradation in marine environment

    Digital Repository Service at National Institute of Oceanography (India)

    David, J.; Gupta, R.; Mohandass, C.; Nair, S.; LokaBharathi, P.A.; Chandramohan, D.

    strains were found to degrade crude oil. Some of the bacterial strains could degrade more than 90% of the aliphatic fractions and more than 50% of the aromatic component. These could also oxidize pure aromatics like naphthalene (80%) and anthracene (55...

  10. Screening and degrading characteristics and community structure of a high molecular weight polycyclic aromatic hydrocarbon-degrading bacterial consortium from contaminated soil

    Institute of Scientific and Technical Information of China (English)

    Run Sun; Jinghua Jin; Guangdong Sun; Ying Liu; Zhipei Liu

    2010-01-01

    Inoculation with efficient microbes had been proved to be the most important way for the bioremediation of polluted environments.For the treatment of abandoned site of Beijing Coking Chemical Plant contaminated with high level of high-molecular-weight polycyclic aromatic hydrocarbons (HMW-PAHs),a bacterial consortium capable of degrading HMW-PAHs,designated 1-18-1,was enriched and screened from HMW-PAHs contaminated soil.Its degrading ability was analyzed by high performance liquid chromatography (HPLC),and the community structure was investigated by construction and analyses of the 16S rRNA gene clone libraries (A,B and F) at different transfers.The results indicated that 1-18-1 was able to utilize pyrene,fluoranthene and benzo[a]pyrene as sole carbon and energy source for growth.The degradation rate of pyrene and fluoranthene reached 82.8% and 96.2% after incubation for 8 days at 30℃,respectively;while the degradation rate of benzo[a]pyrene was only 65.1% after incubation for 28 days at 30℃.Totally,108,100 and 100 valid clones were randomly selected and sequenced from the libraries A,B,and E Phylogenetic analyses showed that all the clones could be divided into 5 groups,Bacteroidetes,α-Proteobacteria,Actinobacteria,β-Proteobacteria and γ-Proteobacteria.Sequence similarity analyses showed total 39 operational taxonomic units (OTUs) in the libraries.The predominant bacterial groups were α-Proteobacteria (19 OTUs,48.7%),γ-Proteobacteria (9 OTUs,23.1%) and β-Protcobacteria (8 OTUs,20.5%).During the transfer process,the proportions of α-Proteobacteria and β-Proteobacteria increased greatly (from 47% to 93%),while γ-Proteobacteria decreased from 32% (library A) to 6% (library F);and Bacteroidetes group disappeared in libraries B and F.

  11. Effect of humic deposit (leonardite) on degradation of semi-volatile and heavy hydrocarbons and soil quality in crude-oil-contaminated soil.

    Science.gov (United States)

    Turgay, Oguz Can; Erdogan, Esin Eraydın; Karaca, Ayten

    2010-11-01

    In order to investigate the bioremedial potential of humic deposit (leonardite), the effects of the treatments of leonardite and a commercial bioaugmentation agent on the degradation of a variety of petroleum hydrocarbons (C13-C31) and soil enzyme activities (urease acid-alkaline phosphatase and dehydrogenase) were tested within a soil incubation experiment lasting 120 days. Experimentally crude-oil-contaminated soil (2.5%) was regulated to a C:N:P ratio (100:15:1; Oilcon), amended with 5% of leonardite and regulated to the same C:N:P ratio (Oilcon-L) or mixed with a commercial bioaugmentation product (Oilcon-B), respectively. In the short period of incubation (60 days), Oilcon and Oilcon-B treatments showed higher hydrocarbon degradations, whereas Oilcon-L showed higher hydrocarbon degradation over Oilcon and Oilcon-B treatments in the long-term (120 days). Applying contaminated soil with leonardite increased urease (LSD, 4.978, *Pacid and alkaline phosphatase activities showed no certain inclination between different treatments. Dehydrogenase seemed to be more related to hydrocarbon degradation process. Overall results showed that leonardite enhanced biodegradation of petroleum hydrocarbons and also stimulated soil ecological quality measured as soil enzyme activities. PMID:19888662

  12. Improvement of Bioremediation Performance for the Degradation of Petroleum Hydrocarbons in Contaminated Sediments

    OpenAIRE

    Laura Rocchetti; Francesca Beolchini; Maurizio Ciani; Antonio Dell'Anno

    2011-01-01

    Microcosm bioremediation strategies were applied to sediments contaminated with hydrocarbons. Experiments were performed in aerobic conditions in a single-step treatment and in a two-step anaerobic-aerobic treatment. In aerobic conditions, either inorganic nutrients or composts were added to the microcosms, while, in the first anaerobic phase of the two-step experiment, acetate and/or allochthonous sulfate-reducing bacteria were used. After the treatment under anaerobic conditions, samples we...

  13. Degradation of polycyclic aromatic hydrocarbons by Pseudomonas sp.JM2 isolated from active sewage sludge of chemical plant

    Institute of Scientific and Technical Information of China (English)

    Jing Ma; Li Xu; Lingyun Jia

    2012-01-01

    It is important to screen strains that can decompose polycyclic aromatic hydrocarbons (PAHs) completely and rapidly with good adaptability for bioremediation in a local area.A bacterial strain JM2,which uses phenanthrene as its sole carbon source,was isolated from the active sewage sludge from a chemical plant in Jilin,China and identified as Pseudomonas based on 16S rDNA gene sequence analysis.Although the optimal growth conditions were determined to be pH 6.0 and 37℃,JM2 showed a broad pH and temperature profile.At pH 4.5 and 9.3,JM2 could degrade more than 40% of fluorene and phenanthrene (50 mg/L each) within 4 days.In addition,when the temperature was as low as 4℃,JM2 could degrade up to 24% fluorene and 12% phenanthrene.This showed the potential for JM2 to be applied in bioremediation over winter or in cold regions.Moreover,a nutrient augmentation study showed that adding formate into media could promote PAH degradation,while the supplement of salicylate had an inhibitive effect.Furthermore,in a metabolic pathway study,salicylate,phthaiic acid,and 9-fluorenone were detected during the degradation of fluorene or phenanthrene.In conclusion,Pseudomonas sp.JM2 is a high performance strain in the degradation of fluorene and phenanthrene under extreme pH and temperature conditions.It might be useful in the bioremediation of PAHs.

  14. Marine Oil-Degrading Microorganisms and Biodegradation Process of Petroleum Hydrocarbon in Marine Environments: A Review.

    Science.gov (United States)

    Xue, Jianliang; Yu, Yang; Bai, Yu; Wang, Liping; Wu, Yanan

    2015-08-01

    Due to the toxicity of petroleum compounds, the increasing accidents of marine oil spills/leakages have had a significant impact on our environment. Recently, different remedial techniques for the treatment of marine petroleum pollution have been proposed, such as bioremediation, controlled burning, skimming, and solidifying. (Hedlund and Staley in Int J Syst Evol Microbiol 51:61-66, 2001). This review introduces an important remedial method for marine oil pollution treatment-bioremediation technique-which is considered as a reliable, efficient, cost-effective, and eco-friendly method. First, the necessity of bioremediation for marine oil pollution was discussed. Second, this paper discussed the species of oil-degrading microorganisms, degradation pathways and mechanisms, the degradation rate and reaction model, and the factors affecting the degradation. Last, several suggestions for the further research in the field of marine oil spill bioremediation were proposed. PMID:25917503

  15. Microbial Degradation of Phenols and Aromatic Hydrocarbons in Creosote-contaminated Groundwater Under Nitrate-reducing Conditions

    DEFF Research Database (Denmark)

    Flyvbjerg, John; Arvin, Erik; Jensen, Bjørn K.;

    1993-01-01

    Batch experiments were carried out to investigate the biodegradation of phenols and aromatic hydrocarbons under anaerobic, nitrate-reducing conditions in groundwater from a creosote-contaminated site at Fredensborg, Denmark. The bacteria in the creosote-contaminated groundwater degraded a mixture...... of toluene, phenol, the cresols (o-, m- and p-cresol) and the dimethylphenols 2,4-DMP and 3,4-DMP at both 10° and 20°C. Benzene, the xylenes, napthalene, 2,3-DMP, 2,5-DMP, 2,6-DMP and 3,5-DMP were resistant to biodegradation during 7–12 months of incubation. It was demonstrated that the degradation...... of toluene, 2,4-DMP, 3,4-DMP and p-cresol depended on nitrate or nitrite as electron acceptors. 40–80% of the nitrate consumed during degradation of the aromatic compounds was recovered as nitrite, and the consumption of nitrate was accompanied by a production of ATP. Stoichiometric calculations indicated...

  16. Evaluation of the effects of a polyurethane carrier on the degradation of chlorinated anilines by Pseudomonas acidovorans CA50

    International Nuclear Information System (INIS)

    A previously described model system for the treatment of harzardous chloroaniline-containing waste waters using immobilized bacterial cells in a bioreactor was enhanced in its degradation efficiency. This was achieved by the substitution of the calcium alginate beads by an inert polyurethane (PU)-carrier. The supply of chloroaniline-polluted waste waters with the PU-carrier (1.25% w/v) resulted in a distinct decrease of the pollutant concentrations in the solution due to the effects of adsorption. Nevertheless, the initially bound amounts of the chloroanilines, were also degraded, which was proved by the chloride balance. In comparative batch-degradation experiments with the Pseudomonas acidovorans strain CA50 with and without the addition of the PU-carrier (1.25% v/w), respectively, the advantages of the PU-supplied treatment system were demonstrated; among others a marked shortening of the degradation periods was achieved. The advantage of the PU-carrier was also shown by using a bubble reactor. In this connection, it is particularly worth mentioning, that high degradation rates can be achieved for a long time even for strongly persistent pollutants. (orig.)

  17. Metagenome reveals potential microbial degradation of hydrocarbon coupled with sulfate reduction in an oil-immersed chimney from Guaymas Basin

    Directory of Open Access Journals (Sweden)

    Ying eHe

    2013-06-01

    Full Text Available Deep-sea hydrothermal vent chimneys contain a high diversity of microorganisms, yet the metabolic activity and the ecological functions of the microbial communities remain largely unexplored. In this study, a metagenomic approach was applied to characterize the metabolic potential in a Guaymas hydrothermal vent chimney and to conduct comparative genomic analysis among a variety of environments with sequenced metagenomes. Complete clustering of functional gene categories with a comparative metagenomic approach showed that this Guaymas chimney metagenome was clustered most closely with a chimney metagenome from Juan de Fuca. All chimney samples were enriched with genes involved in recombination and repair, chemotaxis and flagellar assembly, highlighting their roles in coping with the fluctuating extreme deep-sea environments. A high proportion of transposases was observed in all the metagenomes from deep-sea chimneys, supporting the previous hypothesis that horizontal gene transfer may be common in the deep-sea vent chimney biosphere. In the Guaymas chimney metagenome, thermophilic sulfate reducing microorganisms including bacteria and archaea were found predominant, and genes coding for the degradation of refractory organic compounds such as cellulose, lipid, pullullan, as well as a few hydrocarbons including toluene, ethylbenzene and o-xylene were identified. Therefore, this oil-immersed chimney supported a thermophilic microbial community capable of oxidizing a range of hydrocarbons that served as electron donors for sulphate reduction under anaerobic conditions.

  18. Comparative metagenomics demonstrating different degradative capacity of activated biomass treating hydrocarbon contaminated wastewater.

    Science.gov (United States)

    Yadav, Trilok Chandra; Pal, Rajesh Ramavadh; Shastri, Sunita; Jadeja, Niti B; Kapley, Atya

    2015-01-01

    This study demonstrates the diverse degradative capacity of activated biomass, when exposed to different levels of total dissolved solids (TDS) using a comparative metagenomics approach. The biomass was collected at two time points to examine seasonal variations. Four metagenomes were sequenced on Illumina Miseq platform and analysed using MG-RAST. STAMP tool was used to analyse statistically significant differences amongst different attributes of metagenomes. Metabolic pathways related to degradation of aromatics via the central and peripheral pathways were found to be dominant in low TDS metagenome, while pathways corresponding to central carbohydrate metabolism, nitrogen, organic acids were predominant in high TDS sample. Seasonal variation was seen to affect catabolic gene abundance as well as diversity of the microbial community. Degradation of model compounds using activated sludge demonstrated efficient utilisation of single aromatic ring compounds in both samples but cyclic compounds were not efficiently utilised by biomass exposed to high TDS.

  19. 有机氯农药微生物降解技术研究进展%Progress in Degradation of Organo-chlorinated Pesticides by Microorganism

    Institute of Scientific and Technical Information of China (English)

    卢向明; 陈萍萍

    2012-01-01

    文章综述了有机氯农药的污染化学特征、环境介质中的分布水平、降解功能微生物的种类以及典型有机氯农药的降解途径等,并对有机氯农药微生物降解相关的酶和基因以及降解机理进行了重点讨论.参与有机氯农药微生物降解过程的酶主要有脱氯化氢酶、水解酶和脱氢酶三种,它们通过共代谢,中间协同代谢或矿化等作用完成降解过程.相关降解基因主要是Lin家族基因,包括LinA~LinJ的10个典型功能基因编码.微生物降解有机氯农药的机理主要包括矿化作用、共代谢作用、种间协同代谢作用、活化作用和间接作用等,其中矿化过程包括氧化、还原、水解、脱水、脱卤和裂解等生化反应.由于有机氯农药的持久性和广泛污染性,其降解机理及中间产物的类型、毒性以及新型降解菌的效能开发仍是该领域今后的研究重点.%This paper reviewed the recent research advances in organo-chlorinated pesticide degradation by microorganism, focusing on topics such as enzyme, gene and the biodegradation mechanism. Main enzymes introduced in this paper refered to de-hydro-chlorination enzyme, hydrolytic enzyme and dehydrogenase, and the genes related were ten Lin family genes including the typical functional codes from Lin A to J. Owing to the difficulties involved in controlling pollution of organo-chlorinated pesticides in terms of their extent of application and persistence in the environment, the paper made suggestions for strengthening the research in this area.

  20. Identification of chlorinated solvents degradation zones in clay till by high resolution chemical, microbial and compound specific isotope analysis

    DEFF Research Database (Denmark)

    Damgaard, Ida; Bjerg, Poul Løgstrup; Bælum, Jacob;

    2013-01-01

    subsampling of the clay till cores. The study demonstrates that an integrated approach combining chemical analysis, molecular microbial tools and compound specific isotope analysis (CSIA) was required in order to document biotic and abiotic degradations in the clay till system. © 2013 Elsevier B.V....

  1. Biosurfactant production from marine hydrocarbon-degrading consortia and pure bacterial strains using crude oil as carbon source

    Directory of Open Access Journals (Sweden)

    Eleftheria eAntoniou

    2015-04-01

    Full Text Available Biosurfactants (BS are green amphiphilic molecules produced by microorganisms during biodegradation, increasing the bioavailability of organic pollutants. In this work, the BS production yield of marine hydrocarbon degraders isolated from Elefsina bay in Eastern Mediterranean Sea has been investigated. The drop collapse test was used as a preliminary screening test to confirm biosurfactant producing strains or mixed consortia. The community structure of the best consortia based on the drop collapse test was determined by 16S-rDNA pyrotag screening. Subsequently, the effect of incubation time, temperature, substrate and supplementation with inorganic nutrients, on biosurfactant production, was examined. Two types of BS - lipid mixtures were extracted from the culture broth; the low molecular weight BS Rhamnolipids and Sophorolipids. Crude extracts were purified by silica gel column chromatography and then identified by thin layer chromatography (TLC and Fourier transform infrared spectroscopy (FT-IR. Results indicate that biosurfactant production yield remains constant and low while it is independent of the total culture biomass, carbon source, and temperature. A constant BS concentration in a culture broth with continuous degradation of crude oil implies that the BS producing microbes generate no more than the required amount of biosurfactants that enables biodegradation of the crude oil. Isolated pure strains were found to have higher specific production yields than the complex microbial marine community-consortia. The heavy oil fraction of crude oil has emerged as a promising substrate for BS production (by marine BS producers with fewer impurities in the final product. Furthermore, a particular strain isolated from sediments, Paracoccus marcusii, may be an optimal choice for bioremediation purposes as its biomass remains trapped in the hydrocarbon phase, not suffering from potential dilution effects by sea currents.

  2. Biosurfactant production from marine hydrocarbon-degrading consortia and pure bacterial strains using crude oil as carbon source.

    Science.gov (United States)

    Antoniou, Eleftheria; Fodelianakis, Stilianos; Korkakaki, Emmanouela; Kalogerakis, Nicolas

    2015-01-01

    Biosurfactants (BSs) are "green" amphiphilic molecules produced by microorganisms during biodegradation, increasing the bioavailability of organic pollutants. In this work, the BS production yield of marine hydrocarbon degraders isolated from Elefsina bay in Eastern Mediterranean Sea has been investigated. The drop collapse test was used as a preliminary screening test to confirm BS producing strains or mixed consortia. The community structure of the best consortia based on the drop collapse test was determined by 16S-rDNA pyrotag screening. Subsequently, the effect of incubation time, temperature, substrate and supplementation with inorganic nutrients, on BS production, was examined. Two types of BS - lipid mixtures were extracted from the culture broth; the low molecular weight BS Rhamnolipids and Sophorolipids. Crude extracts were purified by silica gel column chromatography and then identified by thin layer chromatography and Fourier transform infrared spectroscopy. Results indicate that BS production yield remains constant and low while it is independent of the total culture biomass, carbon source, and temperature. A constant BS concentration in a culture broth with continuous degradation of crude oil (CO) implies that the BS producing microbes generate no more than the required amount of BSs that enables biodegradation of the CO. Isolated pure strains were found to have higher specific production yields than the complex microbial marine community-consortia. The heavy oil fraction of CO has emerged as a promising substrate for BS production (by marine BS producers) with fewer impurities in the final product. Furthermore, a particular strain isolated from sediments, Paracoccus marcusii, may be an optimal choice for bioremediation purposes as its biomass remains trapped in the hydrocarbon phase, not suffering from potential dilution effects by sea currents. PMID:25904907

  3. 环境监测用5种氯代烯烃混合气体标准样品研制%Development of a Standard Reference Material Containing 5 Chlorinated Hydrocarbons for Environmental Monitoring

    Institute of Scientific and Technical Information of China (English)

    李宁; 范洁; 王倩; 樊强

    2014-01-01

    The development of reference material of the mixed gas of five hydrochloric hydrocarbons was described. Vinyl chloride is gas, 1, 1-Dichloroethylene cis-1,2-Dichloroethene, Trichloroethylene, Trichloroethylene, Tetrachloroethylene are liquid at room temperature, and so it is difficult to prepare an accurate a standard Reference Material containing 5 Chlorinated hydrocarbons. This research adopts two-step weighting method to prepare the standard gas of five hydrochloric hydrocarbons, and the relative standard deviation of preparation repeatability is less than 1�6%. The experimental method of within-bottle homogeneity of 5 chlorinated hydrocarbon gas standards was developed, and whether the trend for the values varying with the sample pressure changed was used to investigate the sample homogeneity. Based on experimental results, 5 volatile chlorinated hydrocarbons standard gas is homogeneous, and the minimum pressure was determined as 1MPa. The experiment design and data evaluation of long-stability is according to ISO Guide 35 ( Reference materials-General and statistical principles for certification) . Individual Sample was measured as time elapses over a period of 12 months under identical conditions. The analytical data showed no instability was observed and all 5 chlorinated hydrocarbons in treated aluminum gas cylinders was stable for as long as 12 months. The relative expanded uncertainty is 3%( confidence coefficient is 95%) .%介绍了1μmol/mol氮气中5种氯代烯气体标准样品的研制方法。这5种氯代烯包括氯乙烯、1,1-二氯乙烯、顺1,2-二氯乙烯、三氯乙烯、四氯乙烯,其中氯乙烯常温下为气态,其他4种为液态,并且沸点低,将这几种氯代烯制备成气体标准样品存在制备精度低、气液转换不完全等困难。经研究,采用2步称量法制备5种氯代烯气体标准样品,重复制备的相对标准偏差小于1�6%。建立了5种氯代烯标准气体瓶内均匀性

  4. Production of biosurfactant by hydrocarbon degrading Rhodococcus ruber and Rhodococcus erythropolis

    Directory of Open Access Journals (Sweden)

    Bicca Flávio Correa

    1999-01-01

    Full Text Available There is world wide concern about the liberation of hydrocarbons in the environment, both from industrial activities and from accidental spills of oil and oilrelated compounds. Biosurfactants, which are natural emulsifiers of hydrocarbons, are produced by some bacteria, fungi and yeast. They are polymers, totally or partially extracellular, with an amphipathyc structure, which allows them to form micelles that accumulate at the interface between liquids of different polarities such as water and oil. This process is based upon the ability of biosurfactants to reduce surface tension, blocking the formation of hydrogen bridges and certain hydrophilic and hydrophobic interactions. The ability of biosurfactant production by five strains of Rhodococcus isolated from oil prospecting sites was evaluated. Surface tension measurement and emulsifying index were used to quantify biosurfactant production. The influence of environmental conditions was also investigated - pH, temperature, medium composition, and type of carbon source - on cell growth and biosurfactant production. Strain AC 239 was shown to be a potential producer, attaining 63% of emulsifying index for a Diesel-water binary system. It could be used, either directly on oil spills in contained environments, or for the biotechnological production of biosurfactant.

  5. Evolution of Hydrocarbon-Degrading Microbial Communities in the Aftermath of the Deepwater Horizon Oil Well Blowout in the Gulf of Mexico

    Science.gov (United States)

    Andersen, G.; Dubinsky, E. A.; Chakraborty, R.; Hollibaugh, J. T.; Hazen, T. C.

    2012-12-01

    The Deepwater Horizon oil spill created large plumes of dispersed oil and gas that remained deep in the water column and stimulated growth of several deep-sea bacteria that can degrade hydrocarbons at cold temperatures. We tracked microbial community composition before, during and after the 83-day spill to determine relationships between microbial dynamics, and hydrocarbon and dissolved-oxygen concentrations. Dominant bacteria in plumes shifted drastically over time and were dependent on the concentration of hydrocarbons, and the relative quantities of insoluble and soluble oil fractions. Unmitigated flow from the wellhead early in the spill resulted in the highest concentrations of oil and relatively more n-alkanes suspended in the plume as small oil droplets. These conditions resulted in near complete dominance by alkane-degrading Oceanospirillales, Pseudomonas and Shewanella. Six-weeks into the spill overall hydrocarbon concentrations in the plume decreased and were almost entirely composed of BTEX after management actions reduced emissions into the water column. These conditions corresponded with the emergence of Colwellia, Pseudoalteromonas, Cycloclasticus and Halomonas that are capable of degrading aromatic compounds. After the well was contained dominant plume bacteria disappeared within two weeks after the spill and transitioned to an entirely different set of bacteria dominated by Flavobacteria, Methylophaga, Alteromonas and Rhodobacteraceae that were found in anomalous oxygen depressions throughout August and are prominent degraders of both high molecular weight organic matter as well as hydrocarbons. Bio-Sep beads amended with volatile hydrocarbons from MC-252 oil were used from August through September to create hydrocarbon-amended traps for attracting oil-degrading microbes in situ. Traps were placed at multiple depths on a drilling rig about 600-m from the original MC-252 oil spill site. Microbes were isolated on media using MC-252 oil as the sole

  6. DETECTION OF A MICROBIAL CONSORTIUM, INCLUDING TYPE 2 METHANOTROPHS, BY USE OF PHOSPHOLIPID FATTY ACIDES IN AN AEROBIC HALOGENATED HYDROCARBON-DEGRADING SOIL COLUMN ENRICHED WITH NATURAL GAS

    Science.gov (United States)

    The phospholipid ester-linked normal and lipopolysaccharide layer hydroxy fatty acids from microbes in a natural gas (85% methane)-stimulated soil column capable of degrading halogenated hydrocarbons were analyzed in detail by capillary column GC-MS. Microbial biomass, calculated...

  7. Draft Genome Sequence of the Hydrocarbon-Degrading Bacterium Alcanivorax dieselolei KS-293 Isolated from Surface Seawater in the Eastern Mediterranean Sea

    KAUST Repository

    Barbato, Marta

    2015-12-10

    We report here the draft genome sequence of Alcanivorax dieselolei KS-293, a hydrocarbonoclastic bacterium isolated from the Mediterranean Sea, by supplying diesel oil as the sole carbon source. This strain contains multiple putative genes associated with hydrocarbon degradation pathways and that are highly similar to those described in A. dieselolei type strain B5.

  8. Complete Genome Sequence of a Bacterium Representing a Deep Uncultivated Lineage within the Gammaproteobacteria Associated with the Degradation of Polycyclic Aromatic Hydrocarbons

    Science.gov (United States)

    Dickey, Allison N.; Scholl, Elizabeth H.; Wright, Fred A.; Aitken, Michael D.

    2016-01-01

    The bacterial strain TR3.2, representing a novel deeply branching lineage within the Gammaproteobacteria, was isolated and its genome sequenced. This isolate is the first cultivated representative of the previously described “Pyrene Group 2” (PG2) and represents a variety of environmental sequences primarily associated with petrochemical contamination and aromatic hydrocarbon degradation.

  9. Isolation of Marine Polycyclic Aromatic Hydrocarbon (PAH)-Degrading Cycloclasticus Strains from the Gulf of Mexico and Comparison of Their PAH Degradation Ability with That of Puget Sound Cycloclasticus Strains

    OpenAIRE

    Geiselbrecht, Allison D.; Hedlund, Brian P.; Tichi, Mary A.; Staley, J T

    1998-01-01

    Phenanthrene- and naphthalene-degrading bacteria were isolated from four offshore and nearshore locations in the Gulf of Mexico by using a modified most-probable-number technique. The concentrations of these bacteria ranged from 102 to 106 cells per ml of wet surficial sediment in mildly contaminated and noncontaminated sediments. A total of 23 strains of polycyclic aromatic hydrocarbon (PAH)-degrading bacteria were obtained. Based on partial 16S ribosomal DNA sequences and phenotypic charact...

  10. Bacterial diversity exploration in hydrocarbon polluted soil: metabolic potential and degrader community evolution revealed by isotope labeling

    International Nuclear Information System (INIS)

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous compounds produced by incomplete combustion of organic matter. They are a source of environmental pollution, especially associated to oil product exploitation, and represent a threat for living organisms including human beings because of their toxicity. Many bacteria capable of degrading PAHs have been isolated and studied. However, since less than 5% of soil bacteria can be cultivated in the laboratory, bacterial species able to degrade PAHs in situ have been poorly studied. The first goal of this study was to identify bacteria that degrade PAHs in soil using culture-independent molecular methods. To this end, a strategy known a stable isotope probing has been implemented based on the use of phenanthrene, a three rings PAH, in which the natural isotope of carbon was replaced by 13C. This molecule has been introduced as a tracer in microcosms containing soil from a constructed wetlands collecting contaminated water from highway runoff. Bacteria having incorporated the 13C were then identified by 16S rRNA gene sequence analysis after PCR amplification from labeled genomic DNA extracted from soil. The results show that so far little studied Betaproteobacteria, belonging to the genera Acidovorax, Rhodoferax, Hydrogenophaga and Thiobacillus, as well as Rhodocyclaceae, were the key players in phenanthrene degradation. Predominance of Betaproteobacteries was established thanks to quantitative PCR measurements. A dynamic analysis of bacterial diversity also showed that the community structure of degraders depended on phenanthrene bioavailability. In addition, the phylogenetic diversity of ring-hydroxylating di-oxygenases, enzymes involved in the first step of PAH degradation, has been explored. We detected new sequences, mostly related to di-oxygenases from Sphingomonadales and Burkholderiales. For the first time, we were able to associate a catalytic activity for oxidation of PAHs to partial gene sequences amplified

  11. Degradation of chlorinated organic solvents in aqueous percarbonate system using zeolite supported nano zero valent iron (Z-nZVI) composite.

    Science.gov (United States)

    Danish, Muhammad; Gu, Xiaogang; Lu, Shuguang; Naqvi, Muhammad

    2016-07-01

    Chlorinated organic solvents (COSs) are extensively detected in contaminated soil and groundwater that pose long-term threats to human life and environment. In order to degrade COSs effectively, a novel catalytic composite of natural zeolite-supported nano zero valent iron (Z-nZVI) was synthesized in this study. The performance of Z-nZVI-catalyzed sodium percarbonate (SPC) in a heterogeneous Fenton-like system was investigated for the degradation of COSs such as 1,1,1-trichloroethane (1,1,1-TCA) and trichloroethylene (TCE). The surface characteristics and morphology of the Z-nZVI composite were tested using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Total pore volume, specific surface area, and pore size of the natural zeolite and the Z-nZVI composite were measured using Brunauer-Emmett-Teller (BET) method. SEM and TEM analysis showed significant elimination of aggregation and well dispersion of iron nano particles on the framework of natural zeolite. The BET N2 measurement analysis indicated that the surface area of the Z-nZVI composite was 72.3 m(2)/g, much larger than that of the natural zeolite (0.61 m(2)/g). For the contaminant analysis, the samples were extracted with n-hexane and analyzed through gas chromatograph. The degradation of 1,1,1-TCA and TCE in the Z-nZVI-catalyzed percarbonate system were 48 and 39 % respectively, while strong augmentation was observed up to 83 and 99 %, respectively, by adding the reducing agent (RA), hydroxyl amine (NH2OH•HCl). Probe tests validated the presence of OH(●) and O2 (●-) which were responsible for 1,1,1-TCA and TCE degradation, whereas both free radicals were strengthened with the addition of RA. In conclusion, the Z-nZVI/SPC oxidation with reducing agent shows potential technique for degradation of groundwater contaminated by 1,1,1-TCA and TCE. PMID:27023817

  12. [Study on degradation of polycyclic aromatic hydrocarbons (PAHs) with different additional carbon sources in aged contaminated soil].

    Science.gov (United States)

    Yin, Chun-Qin; Jiang, Xin; Wang, Fang; Wang, Cong-Ying

    2012-02-01

    This study was conducted with different additional carbon sources (such as: glucose, DL-malic acid, citrate, urea and ammonium acetate) to elucidate the degradation of polycyclic aromatic hydrocarbons (PAHs) in aged contaminated soil under an indoor simulation experiment. The results showed that the quantity of CO2 emission in different additional carbon sources treatments was obviously much more than that of check treatment in the first week, and the quantity of CO2 emission in DL-malic acid treatment was the largest. The average CO2 production decreased in an order urea > glucose approximately citrate approximately DL-malic acid approximately ammonium acetate > check. Meanwhile, the amount of volatized PAHs in applied carbon sources treatments was significantly less than that in check treatment. The amount of three volatized PAHs decreased in an order phenanthrene > fluoranthene > benzo(b)fluoranthene. Compared with the check treatment, the average degradation rates of the three PAHs were significantly augmented in the supplied carbon sources treatments, in which rates of the three PAHs were much higher in DL-malic acid and urea treatments than those in other treatments. The largest proportion of residual was benzo(b)fluoranthene (from 72% to 81%) among three PAHs compounds, followed by fluoranthene (from 53% to 70% ) and phenanthrene (from 27% to 44%).

  13. Analysis of annatto (Bixa orellana) food coloring formulations. 2. Determination of aromatic hydrocarbon thermal degradation products by gas chromatography.

    Science.gov (United States)

    Scotter, M J; Wilson, L A; Appleton, G P; Castle, L

    2000-02-01

    Twenty samples of commercial annatto formulations have been analyzed for m-xylene and toluene using ambient alkaline hydrolysis, followed by solvent extraction and capillary gas chromatography. Fifteen of the samples contained <5 mg/kg toluene, four samples contained between 5 and 10 mg/kg toluene, and one sample contained 12 mg/kg toluene. The amounts found of m-xylene were 200 mg/kg (one sample), 160 mg/kg (one sample), between 30 and 88 mg/kg (four samples), between 7 and 25 mg/kg (seven samples), and <5 mg/kg (seven samples). Bixin-in-oil formulations contained the highest m-xylene concentrations and also gave the largest increase in headspace m-xylene concentration when heated in closed systems. The results are evidence for the thermal degradation of annatto during source extraction and processing, resulting in contamination by internal generation of both bixin and norbixin types with aromatic hydrocarbons. Two samples of norbixin of known production history (i. e., thermal versus nonthermal processes) were analyzed specifically to identify possible differences in their degradation component profiles. They were found to differ significantly in m-xylene content, which is consistent with their respective production histories. PMID:10691661

  14. Robust Hydrocarbon Degradation and Dynamics of Bacterial Communities during Nutrient-Enhanced Oil Spill Bioremediation

    OpenAIRE

    Röling, Wilfred F. M.; Milner, Michael G.; Jones, D. Martin; Lee, Kenneth; Daniel, Fabien; Swannell, Richard J. P.; Head, Ian M.

    2002-01-01

    Degradation of oil on beaches is, in general, limited by the supply of inorganic nutrients. In order to obtain a more systematic understanding of the effects of nutrient addition on oil spill bioremediation, beach sediment microcosms contaminated with oil were treated with different levels of inorganic nutrients. Oil biodegradation was assessed respirometrically and on the basis of changes in oil composition. Bacterial communities were compared by numerical analysis of denaturing gradient gel...

  15. Strong Impact on the Polycyclic Aromatic Hydrocarbon (PAH)-Degrading Community of a PAH-Polluted Soil but Marginal Effect on PAH Degradation when Priming with Bioremediated Soil Dominated by Mycobacteria

    DEFF Research Database (Denmark)

    Johnsen, Anders R.; Schmidt, Stine; Hybholdt, Trine K.;

    2007-01-01

    Bioaugmentation of soil polluted with polycyclic aromatic hydrocarbons (PAHs) is often disappointing because of the low survival rate and low activity of the introduced degrader bacteria. We therefore investigated the possibility of priming PAH degradation in soil by adding 2% of bioremediated soil...... with a high capacity for PAH degradation. The culturable PAH-degrading community of the bioremediated primer soil was dominated by Mycobacterium spp. A microcosm containing pristine soil artificially polluted with PAHs and primed with bioremediated soil showed a fast, 100- to 1,000-fold increase in numbers...... of culturable phenanthrene-, pyrene-, and fluoranthene degraders and a 160-fold increase in copy numbers of the mycobacterial PAH dioxygenase gene pdo1. A nonpolluted microcosm primed with bioremediated soil showed a high rate of survival of the introduced degrader community during the 112 days of incubation...

  16. Isolation, identification and diesel-oil biodegradation capacities of indigenous hydrocarbon-degrading strains of Cellulosimicrobium cellulans and Acinetobacter baumannii from tarball at Terengganu beach, Malaysia.

    Science.gov (United States)

    Nkem, Bruno Martins; Halimoon, Normala; Yusoff, Fatimah Md; Johari, Wan Lufti Wan; Zakaria, Mohamad Pauzi; Medipally, Srikanth Reddy; Kannan, Narayanan

    2016-06-15

    In this study, we isolated two indigenous hydrocarbon-degrading bacteria from tarball found in Rhu Sepuluh beach, Terengganu, Malaysia. These bacteria were identified based on their physiological characteristic and 16S rRNA gene sequence analysis, and they showed 99% similarity with Cellulosimicrobium cellulans DSM 43879 and Acinetobacter baumannii ATCC 19606 respectively. Their hydrocarbon-degrading capabilities were tested using diesel-oil as sole carbon source. Results analysed using GC-MS, showed diesel-oil alkanes were degraded an average 64.4% by C. cellulans and 58.1% by A. baumannii with medium optical density reaching 0.967 (C. cellulans) and 1.515 (A. baumannii) in minimal salt media at 32°C for 10days. Individual diesel-oil alkanes were degraded between 10%-95.4% by C. cellulans and 0.2%-95.9% by A. baumannii. Both strains utilized diesel-oil for growth. The study suggests both strains are part of indigenous hydrocarbon-degrading bacteria in tarball with potential for bioremediation of oil-polluted marine environment. PMID:27085593

  17. Isolation of hydrocarbon-degrading and biosurfactant-producing bacteria and assessment their plant growth-promoting traits.

    Science.gov (United States)

    Pacwa-Płociniczak, Magdalena; Płociniczak, Tomasz; Iwan, Joanna; Żarska, Monika; Chorążewski, Mirosław; Dzida, Marzena; Piotrowska-Seget, Zofia

    2016-03-01

    Forty-two hydrocarbon-degrading bacterial strains were isolated from the soil heavily contaminated with petroleum hydrocarbons. Forty-one strains were identified based on their whole-cell fatty acid profiles using the MIDI-MIS method. Thirty-three of them belong to species Rhodococcus erythropolis, while the others to the genera Rahnella (4), Serratia (3) and Proteus (1). Isolates were screened for their ability to produce biosurfactants/bioemulsifiers. For all of them the activity of several mechanisms characteristic for plant growth-promoting bacteria was also determined. In order to investigate surface active and emulsifying abilities of isolates following methods: oil-spreading, blood agar, methylene blue agar and determination of emulsification index, were used. Among studied bacteria 12 strains (CD 112, CD 126, CD 131, CD 132, CD 135, CD 147, CD 154, CD 155, CD 158, CD 161, CD 166 and CD 167) have been chosen as promising candidates for the production of biosurfactants and/or bioemulsifiers. Among them 2 strains (R. erythropolis CD 126 and Rahnella aquatilis CD 132) had the highest potential to be used in the bioaugmentation of PH-contaminated soil. Moreover, 15 of tested strains (CD 105, CD 106, CD 108, CD 111, CD 116, CD 120, CD 124, CD 125, CD 130, CD 132, CD 134, CD 154, CD 156, CD 161 and CD 170) showed the activity of four mechanisms (ACC deaminase activity, IAA and siderophore production, phosphate solubilization) considered to be characteristic for plant growth-promoting bacteria. Two of them (R. erythropolis CD 106 and R. erythropolis CD 111) showed the highest activity of above-mentioned mechanisms and thus are considered as promising agents in microbe assisted phytoremediation. PMID:26708648

  18. Electrochemical degradation of polycyclic aromatic hydrocarbons in creosote solution using ruthenium oxide on titanium expanded mesh anode.

    Science.gov (United States)

    Tran, Lan-Huong; Drogui, Patrick; Mercier, Guy; Blais, Jean-François

    2009-05-30

    In this study, expanded titanium (Ti) covered with ruthenium oxide (RuO(2)) electrode was used to anodically oxidize polycyclic aromatic hydrocarbons (PAH) in creosote solution. Synthetic creosote-oily solution (COS) was prepared with distilled water and a commercial creosote solution in the presence of an amphoteric surfactant; Cocamidopropylhydroxysultaine (CAS). Electrolysis was carried out using a parallelepipedic electrolytic 1.5-L cell containing five anodes (Ti/RuO(2)) and five cathodes (stainless steel, 316 L) alternated in the electrode pack. The effects of initial pH, temperature, retention time, supporting electrolyte, current density and initial PAH concentration on the process performance were examined. Experimental results revealed that a current density of 9.23 mA cm(-2) was beneficial for PAH oxidation. The sum of PAH concentrations for 16 PAHs could be optimally diminished up to 80-82% while imposing a residence time in the electrolysis cell of 90 min. There was not a significant effect of the electrolyte (Na(2)SO(4)) concentration on oxidation efficiency in the investigated range of 500-4000 mg/L. However, an addition of 500 mg Na(2)SO(4)L(-1) was required to reduce the energy consumption and the treatment cost. Besides, there was no effect of initial PAH concentration on oxidation efficiency in the investigated range of 270-540 mg PAHL(-1). Alkaline media was not favourable for PAH oxidation, whereas high performance of PAH degradation could be recorded without initial pH adjustment (original pH around 6.0). Likewise, under optimal conditions, 84% of petroleum hydrocarbon (C(10)-C(50)) was removed, whereas removal yields of 69% and 62% have been measured for O&G and COD, respectively. Microtox and Daphnia biotests showed that electrochemical oxidation using Ti/RuO(2) could be efficiently used to reduce more than 90% of the COS toxicity. PMID:18926633

  19. Interaction between Carbon Nanotubes and Aromatic Hydrocarbon-degrading Microbes and its Effect on Carbon Nanotubes Transformation

    Science.gov (United States)

    You, Y.; Wang, L.; Poulson, S.; Wang, X.; Xing, B.; Yang, Y.

    2015-12-01

    Due to their unique electrical, optical and mechanical properties, carbon nanotubes (CNTs) have been substantially produced and widely applied during the past decades, leading to their increased probability of entering the environment. Some estimation suggests that CNTs are accumulated in agricultural systems with their soil concentration increasing by 0.4-157 ng/kg/year. This has raised concerns about environmental impacts of these emerging contaminants including their ecotoxicity. Meanwhile, transformation of CNTs in the environment can significantly affect their transport, bioavailability and thereby ecotoxicity. So far, environmental biodegradation of CNTs remains obscure. Given the high diversity of soil microorganisms and their metabolic potentials, it is important to investigate microbial biodegradation of CNTs under various environmental conditions. This study focuses on an aromatic hydrocarbon-degrading bacterium, Mycobacterium vanbaalenii PYR-1, as a model microorganism capable of ring cleavage. We hypothesize that bacterial activities could transform CNTs to more hydrophilic forms, increasing their aqueous stability and environmental reactivity. We incubated M. vanbaalenii PYR-1 with 13C-labeded multiwall carbon nanotubes (MWCNTs) for 30 days, monitored δ13C in the system, characterized MWCNTs before and after the reaction, and compared the results with culture-negative controls. To investigate effects of various environmental conditions, including the presence of extracellular oxidative enzymes from white-rot fungi, additional experiments will be conducted and results compared will be compared among different setups. Moreover, we will measure adverse impacts of CNTs on the metabolic activities of M. vanbaalenii PYR-1, particularly its biodegradation of polycyclic aromatic hydrocarbons.

  20. Biochar-carrying hydrocarbon decomposers promote degradation during the early stage of bioremediation

    Science.gov (United States)

    Galitskaya, Polina; Akhmetzyanova, Leisan; Selivanovskaya, Svetlana

    2016-10-01

    Oil pollution is one of the most serious current environmental problems. In this study, four strategies of bioremediation of oil-polluted soil were tested in the laboratory over a period of 84 days: (A) aeration and moistening; (B) amendment with 1 % biochar (w ⁄ w) in combination with A; amendment with 1 % biochar with immobilized Pseudomonas aeruginosa (C) or Acinetobacter radioresistens (D) in combination with A. All strategies used resulted in a decrease of the hydrocarbon content, while biochar addition (B, C, D strategies) led to acceleration of decomposition in the beginning. Microbial biomass and respiration rate increased significantly at the start of bioremediation. It was demonstrated that moistening and aeration were the main factors influencing microbial biomass, while implementation of biochar and introduction of microbes were the main factors influencing microbial respiration. All four remediation strategies altered bacterial community structure and phytotoxicity. The Illumina MiSeq method revealed 391 unique operational taxonomic units (OTUs) belonging to 40 bacterial phyla and a domination of Proteobacteria in all investigated soil samples. The lowest alpha diversity was observed in the samples with introduced bacteria on the first day of remediation. Metric multidimensional scaling demonstrated that in the beginning and at the end, microbial community structures were more similar than those on the 28th day of remediation. Strategies A and B decreased phytotoxicity of remediated soil between 2.5 and 3.1 times as compared with untreated soil. C and D strategies led to additional decrease of phytotoxicity between 2.1 and 3.2 times.

  1. Influence of compost amendments on the diversity of alkane degrading bacteria in hydrocarbon contaminated soils

    Directory of Open Access Journals (Sweden)

    Michael eSchloter

    2014-03-01

    Full Text Available Alkane degrading microorganisms play an important role for bioremediation of petrogenic contaminated environments. In this study, we investigated the effects of compost addition on the diversity of alkane monooxygenase gene (alkB harboring bacteria in oil-contaminated soil originated from an industrial zone in Celje, Slovenia, to improve our understanding about the bacterial community involved in alkane degradation and the effects of amendments. Soil without any amendments (control soil and soil amended with compost of different maturation stages, i 1 year and ii 2 weeks, were incubated under controlled conditions in a microcosm experiment and sampled after 0, 6, 12 and 36 weeks of incubation. By using quantitative real-time PCR higher number of alkB genes could be detected in soil samples with compost compared to the control soil after 6, 12 and 36 weeks mainly if the less maturated compost was added. To get an insight into the composition of the alkB harboring microbial communities, we performed next generation sequencing of alkB gene fragment amplicons. Richness and diversity of alkB gene harboring prokaryotes was higher in soil mixed with compost compared to control soil after 6, 12 and 36 weeks again with stronger effects of the less maturated compost. Comparison of communities detected in different samples and time points based on principle component analysis revealed that the addition of compost in general stimulated the abundance of alkB harboring Actinobacteria during the experiment independent from the maturation stage of the compost compared to the control soils. In addition alkB harboring proteobacteria like Shewanella or Hydrocarboniphaga as well as proteobacteria of the genus Agrobacterium responded positively to the addition of compost to soil The amendment of the less maturated compost resulted in addition in a large increase of alkB harboring bacteria of the Cytophaga group (Microscilla mainly at the early sampling

  2. Comment on 'inflow, levels and the fate of some persistent chlorinated hydrocarbons in the Rijeka Bay area of the Adriatic Sea by N. Picer and M. Picer'

    Digital Repository Service at National Institute of Oceanography (India)

    Sarkar, A.

    highlighted in more detail and more specific with regard to the use of the reagent. (5) It is mentioned that the separation of PCBs from chlorinated insecticides was performed on a miniature silica gel column (Picer and Ahel, 1978). Such a statement does... is needed in order to justify the resolution of the peaks for identification of organochlorine compounds and their quantification. 733 734 Comment Moreover, they have contradicted themselves by employing a range of correction factors from 1.4 to 2...

  3. Isolation and preliminary characterization of a respiratory nitrate reductase from hydrocarbon-degrading bacterium Gordonia alkanivorans S7.

    Science.gov (United States)

    Romanowska, Irena; Kwapisz, Ewa; Mitka, Magdalena; Bielecki, Stanisław

    2010-06-01

    Gordonia alkanivorans S7 is an efficient degrader of fuel oil hydrocarbons that can simultaneously utilize oxygen and nitrate as electron acceptors. The respiratory nitrate reductase (Nar) from this organism has been isolated using ion exchange chromatography and gel filtration, and then preliminarily characterized. PAGE, SDS-PAGE and gel filtration chromatography revealed that Nar consisted of three subunits of 103, 53 and 25 kDa. The enzyme was optimally active at pH 7.9 and 40 degrees C. K(m) values for NO(3)(-) (110 microM) and for ClO(3)(-) (138 microM) were determined for a reduced viologen as an electron donor. The purified Nar did not use NADH as the electron donor to reduce nitrate or chlorate. Azide was a strong inhibitor of its activity. Our results imply that enzyme isolated from G. alkanivorans S7 is a respiratory membrane-bound nitrate reductase. This is the first report of purification of a nitrate reductase from Gordonia species.

  4. Phytoremediation of abandoned crude oil contaminated drill sites of Assam with the aid of a hydrocarbon-degrading bacterial formulation.

    Science.gov (United States)

    Yenn, R; Borah, M; Boruah, H P Deka; Roy, A Sarma; Baruah, R; Saikia, N; Sahu, O P; Tamuli, A K

    2014-01-01

    Environmental deterioration due to crude oil contamination and abandoned drill sites is an ecological concern in Assam. To revive such contaminated sites, afield study was conducted to phytoremediate four crude oil abandoned drill sites of Assam (Gelakey, Amguri, Lakwa, and Borholla) with the aid of two hydrocarbon-degrading Pseudomonas strains designated N3 and N4. All the drill sites were contaminated with 15.1 to 32.8% crude oil, and the soil was alkaline in nature (pH8.0-8.7) with low moisture content, low soil conductivity and low activities of the soil enzymes phosphatase, dehydrogenase and urease. In addition, N, P, K, and C contents were below threshold limits, and the soil contained high levels of heavy metals. Bio-augmentation was achieved by applying Pseudomonas aeruginosa strains N3 and N4 followed by the introduction of screened plant species Tectona grandis, Gmelina arborea, Azadirachta indica, and Michelia champaca. The findings established the feasibility of the phytoremediation of abandoned crude oil-contaminated drill sites in Assam using microbes and native plants. PMID:24933892

  5. The Effect of Interaction Between White-rot Fungi and Indigenous Microorganisms on Degradation of Polycyclic Aromatic Hydrocarbons in Soil

    Energy Technology Data Exchange (ETDEWEB)

    Wiesche, C. in der [Institute of Plant Nutrition and Soil Science, Federal Agricultural Research Centre (Germany)], E-mail: carsten.wiesche@fal.de; Martens, R. [Institute of Agroecology, Federal Agricultural Research Centre (Germany); Zadrazil, F. [Institute of Plant Nutrition and Soil Science, Federal Agricultural Research Centre (Germany)

    2003-05-15

    White-rot fungi applied for soil bioremediation have to compete with indigenous soil microorganisms. The effect of competition on both indigenous soil microflora and white-rot fungi was evaluated with regard to degradation of polycyclic aromatic hydrocarbons (PAH) with different persistence in soil. Sterile and non-sterile soil was artificially contaminated with {sup 14}C-labeled PAH consisting of three (anthracene), four (pyrene, benz[a]anthracene) and five fused aromatic rings (benzo[a]pyrene, dibenz[a,h]anthracene). The two fungi tested,Dichomitus squalens and Pleurotus ostreatus, produced similar amounts of ligninolytic enzymes in soil, but PAH mineralization by P. ostreatus was significantly higher. Compared to the indigenous soil microflora, P.ostreatus mineralized 5-ring PAH to a larger extent, while the indigenous microflora was superior in mineralizing 3-ring and 4-ring PAH. In coculture the special capabilities of both soil microflora and P. ostreatus were partly restricted due to antagonistic interactions, but essentially preserved. Thus, soil inoculation with P. ostreatus significantly increased the mineralization of high-molecular-weight PAH, and at the same time reduced the mineralization of anthracene and pyrene. Regarding the mineralization of low-molecular-weight PAH, the stimulation of indigenous soil microorganisms by straw amendment was more efficient than application of white-rot fungi.

  6. Chlorine isotope investigation of natural attenuation of trichloroethene in an aerobic aquifer

    International Nuclear Information System (INIS)

    Natural attenuation of chlorinated aliphatic hydrocarbons (CAHs) can be an important mechanism for groundwater remediation. It is difficult to determine the effectiveness of natural CAH attenuation from chemical analyses of groundwater samples because mixing, dispersion, and secondary reactions can mask the chemical evidence of attenuation. In this paper, the authors explore the application of stable chlorine isotope ratio measurements as a new tool for evaluating natural attenuation of CAHs. They report stable isotope ratios of chlorine in both trichloroethene (TCE) and inorganic chloride in groundwater from an aerobic aquifer beneath an extensively contaminated industrial site, the Paducah Gaseous Diffusion Plant in western Kentucky. Variations in the concentrations and chlorine isotope ratios of TCE and chloride in the groundwater are consistent with those expected from natural attenuation. These data support a model in which partial TCE degradation occurred in relatively impermeable, clay-rich sediments above the aquifer, and little or no further degradation of TCE occurred within the aquifer. A record of changing conditions within the TCE source area can be inferred from the spatial variation of chlorine isotope ratios for TCE and chloride within the plume

  7. Functional genes to assess nitrogen cycling and aromatic hydrocarbon degradation: primers and processing matter

    Directory of Open Access Journals (Sweden)

    Christopher Ryan Penton

    2013-09-01

    Full Text Available Targeting sequencing to genes involved in key environmental processes, i.e. ecofunctional genes, provides an opportunity to sample nature’s gene guilds to greater depth and help link community structure to process-level outcomes. Vastly different approaches have been implemented for sequence processing and, ultimately, for taxonomic placement of these gene reads. The overall quality of next generation sequence analysis of functional genes is dependent on multiple steps and assumptions of unknown diversity. To illustrate current issues surrounding amplicon read processing we provide examples for three ecofunctional gene groups. A combination of in-silico, environmental and cultured strain sequences was used to test new primers targeting the dioxin and dibenzofuran degrading genes dxnA1, dbfA1, and carAa. The majority of obtained environmental sequences were classified into novel sequence clusters, illustrating the discovery value of the approach. For the nitrite reductase step in denitrification, the well-known nirK primers exhibited deficiencies in reference database coverage, illustrating the need to refine primer-binding sites and/or to design multiple primers, while nirS primers exhibited bias against five phyla. Amino acid-based OTU clustering of these two N-cycle genes from soil samples yielded only 114 unique nirK and 45 unique nirS genus-level groupings, likely a reflection of constricted primer coverage. Finally, supervised and non-supervised OTU analysis methods were compared using the nifH gene of nitrogen fixation, with generally similar outcomes, but the clustering (non-supervised method yielded higher diversity estimates and stronger site-based differences. High throughput amplicon sequencing can provide inexpensive and rapid access to nature’s related sequences by circumventing the culturing barrier, but each unique gene requires individual considerations in terms of primer design and sequence processing and classification.

  8. Hydrocarbon-Degrading Bacteria and Paraffin from Polluted Seashores 9 Years after the Nakhodka Oil Spill in the Sea of Japan

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Pollution of petroleum hydrocarbons, in particular oil spills, has attracted much attention in the past and recent decades. Oil spills influence natural microbial community, and physical and chemical properties of the affected sites. The biodegradation of hydrocarbons by microorganisms is one of the primary ways by which oil spill is eliminated from contaminated sites. One such spill was that of the Russian tanker the Nakhodka that spilled heavy oil into the Sea of Japan on January 2, 1997. The impact of the Nakhodka oil spill resulted in a viscous sticky fluid fouling the shores and affected natural ecosystems. This paper describes the weathering of hydrocarbon-degrading bacteria (genus Pseudomonas) and crystallized organic compounds from the Nakhodka oil spill-polluted seashores after nine years. The Nakhodka oil has hardened and formed crust of crystalline paraffin wax as shown by XRD analysis (0.422, 0.377, and 0.250 nm d-spacing) in association with graphite and calcite after 9years of bioremediation. Anaerobic reverse side of the oil crust contained numerous coccus typed bacteria associated with halite. The finding of hydrocarbon-degrading bacteria and paraffin wax in the oil crust may have a significant effect on the weathering processes of the Nakhodka oil spill during the 9-year bioremediation.

  9. Degradation of polycyclic aromatic hydrocarbons (PAHs) by a mixed culture and its component pure cultures, obtained from PAH-contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Trzesicka-Mlynarz, D.; Ward, O. P.

    1995-06-01

    A mixed culture, isolated from soil contaminated with polycyclic aromatic hydrocarbons (PAHs) grew on and degraded fluoranthene in aqueous media supplemented with glucose, yeast extract and peptone. A pure culture of Pseudomona sp. strain HL7b which was known to degrade fluoranthene was incorporated into initial experiments for comparative purposes. Increased complex nitrogen levels in the aqueous media promoted bacteria growth, and fluoranthene degradation, while high glucose levels diminished fluoranthene degradation. The mixed culture containing 4 Gram-negative rods biodegraded the PAH mixture better than the pure culture. Pure cultures exhibited a good capacity for removal of more water-soluble PAHs, but a lesser capacity for low water-soluble PAHs. 4 tabs., 3 figs., 26 refs.

  10. Degradation of some representative polycyclic aromatic hydrocarbons by the water-soluble protein extracts from Zea mays L. cv PR32-B10.

    Science.gov (United States)

    Barone, Roberto; de Biasi, Margherita-Gabriella; Piccialli, Vincenzo; de Napoli, Lorenzo; Oliviero, Giorgia; Borbone, Nicola; Piccialli, Gennaro

    2016-10-01

    The ability of the water-soluble protein extracts from Zea mais L. cv. PR32-B10 to degrade some representative polycyclic aromatic hydrocarbons (PAHs), has been evaluated. Surface sterilized seeds of corn (Zea mais L. Pioneer cv. PR32-B10) were hydroponically cultivated in a growth chamber under no-stressful conditions. The water-soluble protein extracts isolated from maize tissues showed peroxidase, polyphenol oxidase and catalase activities. Incubation of the extracts with naphthalene, fluorene, phenanthrene and pyrene, led to formation of oxidized and/or degradation products. GC-MS and TLC monitoring of the processes showed that naphthalene, phenanthrene, fluorene and pyrene underwent 100%, 78%, 92% and 65% oxidative degradation, respectively, after 120 min. The chemical structure of the degradation products were determined by (1)H NMR and ESI-MS spectrometry. PMID:27391049

  11. Draft Genome Sequence of Hydrocarbon-Degrading Staphylococcus saprophyticus Strain CNV2, Isolated from Crude Oil-Contaminated Soil from the Noonmati Oil Refinery, Guwahati, Assam, India.

    Science.gov (United States)

    Mukherjee, Arghya; Chettri, Bobby; Langpoklakpam, James S; Singh, Arvind K; Chattopadhyay, Dhrubajyoti

    2016-05-12

    Here, we report the 2.6 Mb draft genome sequence of hydrocarbon-degrading Staphylococcus saprophyticus strain CNV2, isolated from oil-contaminated soil in Guwahati, India. CNV2 contains 2,545 coding sequences and has a G+C content of 33.2%. This is the first report of the genome sequence of an S. saprophyticus adapted to an oil-contaminated environment.

  12. Draft Genome Sequence of Hydrocarbon-Degrading Staphylococcus saprophyticus Strain CNV2, Isolated from Crude Oil-Contaminated Soil from the Noonmati Oil Refinery, Guwahati, Assam, India.

    Science.gov (United States)

    Mukherjee, Arghya; Chettri, Bobby; Langpoklakpam, James S; Singh, Arvind K; Chattopadhyay, Dhrubajyoti

    2016-01-01

    Here, we report the 2.6 Mb draft genome sequence of hydrocarbon-degrading Staphylococcus saprophyticus strain CNV2, isolated from oil-contaminated soil in Guwahati, India. CNV2 contains 2,545 coding sequences and has a G+C content of 33.2%. This is the first report of the genome sequence of an S. saprophyticus adapted to an oil-contaminated environment. PMID:27174281

  13. Electrochemical degradation of polycyclic aromatic hydrocarbons in creosote solution using ruthenium oxide on titanium expanded mesh anode

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Lan-Huong; Drogui, Patrick; Mercier, Guy [Institut National de la Recherche Scientifique (Centre Eau Terre et Environnement), Universite du Quebec, 490 rue de la Couronne, C.P. 7500, Quebec, Qc G1K 9A9 (Canada); Blais, Jean-Francois, E-mail: blaisjf@ete.inrs.ca [Institut National de la Recherche Scientifique (Centre Eau Terre et Environnement), Universite du Quebec, 490 rue de la Couronne, C.P. 7500, Quebec, Qc G1K 9A9 (Canada)

    2009-05-30

    In this study, expanded titanium (Ti) covered with ruthenium oxide (RuO{sub 2}) electrode was used to anodically oxidize polycyclic aromatic hydrocarbons (PAH) in creosote solution. Synthetic creosote-oily solution (COS) was prepared with distilled water and a commercial creosote solution in the presence of an amphoteric surfactant; Cocamidopropylhydroxysultaine (CAS). Electrolysis was carried out using a parallelepipedic electrolytic 1.5-L cell containing five anodes (Ti/RuO{sub 2}) and five cathodes (stainless steel, 316L) alternated in the electrode pack. The effects of initial pH, temperature, retention time, supporting electrolyte, current density and initial PAH concentration on the process performance were examined. Experimental results revealed that a current density of 9.23 mA cm{sup -2} was beneficial for PAH oxidation. The sum of PAH concentrations for 16 PAHs could be optimally diminished up to 80-82% while imposing a residence time in the electrolysis cell of 90 min. There was not a significant effect of the electrolyte (Na{sub 2}SO{sub 4}) concentration on oxidation efficiency in the investigated range of 500-4000 mg/L. However, an addition of 500 mg Na{sub 2}SO{sub 4} L{sup -1} was required to reduce the energy consumption and the treatment cost. Besides, there was no effect of initial PAH concentration on oxidation efficiency in the investigated range of 270-540 mg PAH L{sup -1}. Alkaline media was not favourable for PAH oxidation, whereas high performance of PAH degradation could be recorded without initial pH adjustment (original pH around 6.0). Likewise, under optimal conditions, 84% of petroleum hydrocarbon (C{sub 10}-C{sub 50}) was removed, whereas removal yields of 69% and 62% have been measured for O and G and COD, respectively. Microtox and Daphnia biotests showed that electrochemical oxidation using Ti/RuO{sub 2} could be efficiently used to reduce more than 90% of the COS toxicity.

  14. Characterization of Preferential Ground-Water Seepage From a Chlorinated Hydrocarbon-Contaminated Aquifer to West Branch Canal Creek, Aberdeen Proving Ground, Maryland, 2002-04

    Science.gov (United States)

    Majcher, Emily H.; Phelan, Daniel J.; Lorah, Michelle M.; McGinty, Angela L.

    2007-01-01

    Wetlands act as natural transition zones between ground water and surface water, characterized by the complex interdependency of hydrology, chemical and physical properties, and biotic effects. Although field and laboratory demonstrations have shown efficient natural attenuation processes in the non-seep wetland areas and stream bottom sediments of West Branch Canal Creek, chlorinated volatile organic compounds are present in a freshwater tidal creek at Aberdeen Proving Ground, Maryland. Volatile organic compound concentrations in surface water indicate that in some areas of the wetland, preferential flow paths or seeps allow transport of organic compounds from the contaminated sand aquifer to the overlying surface water without undergoing natural attenuation. From 2002 through 2004, the U.S. Geological Survey, in cooperation with the Environmental Conservation and Restoration Division of the U.S. Army Garrison, Aberdeen Proving Ground, characterized preferential ground-water seepage as part of an ongoing investigation of contaminant distribution and natural attenuation processes in wetlands at this site. Seep areas were discrete and spatially consistent during thermal infrared surveys in 2002, 2003, and 2004 throughout West Branch Canal Creek wetlands. In these seep areas, temperature measurements in shallow pore water and sediment more closely resembled those in ground water than those in nearby surface water. Generally, pore water in seep areas contaminated with chlorinated volatile organic compounds had lower methane and greater volatile organic compound concentrations than pore water in non-seep wetland sediments. The volatile organic compounds detected in shallow pore water in seeps were spatially similar to the dominant volatile organic compounds in the underlying Canal Creek aquifer, with both parent and anaerobic daughter compounds detected. Seep locations characterized as focused seeps contained the highest concentrations of chlorinated parent compounds

  15. Degradation of polycyclic aromatic hydrocarbons in a coking wastewater treatment plant residual by an O3/ultraviolet fluidized bed reactor.

    Science.gov (United States)

    Lin, Chong; Zhang, Wanhui; Yuan, Mengyang; Feng, Chunhua; Ren, Yuan; Wei, Chaohai

    2014-09-01

    Coking wastewater treatment plant (CWWTP) represents a typical point source of polycyclic aromatic hydrocarbons (PAHs) to the water environment and threatens the safety of drinking water in downstream regions. To enhance the removal of residual PAHs from bio-treated coking wastewater, a pilot-scale O3/ultraviolet (UV) fluidized bed reactor (O3/UV FBR) was designed and different operating factors including UV irradiation intensity, pH, initial concentration, contact time, and hydraulic retention time (HRT) were investigated at an ozone level of 240 g h(-1) and 25 ± 3 °C. A health risk evaluation and cost analysis were also carried out under the continuous-flow mode. As far as we know, this is the first time an O3/UV FBR has been explored for PAHs treatment. The results indicated that between 41 and 75 % of 18 target PAHs were removed in O3/UV FBR due to synergistic effects of UV irradiation. Both increased reaction time and increased pH were beneficial for the removal of PAHs. The degradation of the target PAHs within 8 h can be well fitted by the pseudo-first-order kinetics (R (2) > 0.920). The reaction rate was also positively correlated with the initial concentrations of PAHs. The health risk assessment showed that the total amount of carcinogenic substance exposure to surface water was reduced by 0.432 g day(-1). The economic analysis showed that the O3/UV FBR was able to remove 18 target PAHs at a cost of US$0.34 m(-3). These results suggest that O3/UV FBR is efficient in removing residuals from CWWTP, thus reducing the accumulation of persistent pollutant released to surface water.

  16. Degradation of polycyclic aromatic hydrocarbons (PAHs) in contaminated soils by Fenton's reagent: a multivariate evaluation of the importance of soil characteristics and PAH properties.

    Science.gov (United States)

    Jonsson, Sofia; Persson, Ylva; Frankki, Sofia; van Bavel, Bert; Lundstedt, Staffan; Haglund, Peter; Tysklind, Mats

    2007-10-01

    In this study, we investigated how the chemical degradability of polycyclic aromatic hydrocarbons (PAHs) in aged soil samples from various contaminated sites is influenced by soil characteristics and by PAH physico-chemical properties. The results were evaluated using the multivariate statistical tool, partial least squares projections to latent structures (PLS). The PAH-contaminated soil samples were characterised (by pH, conductivity, organic matter content, oxide content, particle size, specific surface area, and the time elapsed since the contamination events, i.e. age), and subjected to relatively mild, slurry-phase Fenton's reaction conditions. In general, low molecular weight PAHs were degraded to a greater extent than large, highly hydrophobic variants. Anthracene, benzo(a)pyrene, and pyrene were more susceptible to degradation than other, structurally similar, PAHs; an effect attributed to the known susceptibility of these compounds to reactions with hydroxyl radicals. The presence of organic matter and the specific surface area of the soil were clearly negatively correlated with the degradation of bi- and tri-cyclic PAHs, whereas the amount of degraded organic matter correlated positively with the degradation of PAHs with five or six fused rings. This was explained by enhanced availability of the larger PAHs, which were released from the organic matter as it degraded. Our study shows that sorption of PAHs is influenced by a combination of soil characteristics and physico-chemical properties of individual PAHs. Multivariate statistical tools have great potential for assessing the relative importance of these parameters.

  17. Application of a biofilm formed by a mixture of yeasts isolated in Vietnam to degrade aromatic hydrocarbon polluted wastewater collected from petroleum storage.

    Science.gov (United States)

    Nhi Cong, Le Thi; Ngoc Mai, Cung Thi; Thanh, Vu Thi; Nga, Le Phi; Minh, Nghiem Ngoc

    2014-01-01

    In this study, three good biofilm-forming yeast strains, including Candida viswanathii TH1, Candida tropicalis TH4 and Trichosporon asahii B1, were isolated from oil-contaminated water and sediment samples collected in coastal zones of Vietnam. These strains were registered in the GenBank database with the accession numbers JX129175, JX129176 and KC139404 for strain TH1, TH4 and B1, respectively. The biofilm formed by a mixture of these organisms degraded 90, 85, 82 and 67% of phenol, naphthalene, anthracene and pyrene, respectively, after a 7-day incubation period using an initial concentration of 600 ppm phenol and 200 ppm of each of the other compounds. In addition, this biofilm completely degraded these aromatic compounds, which were from wastewater collected from petroleum tanks in Do Xa, Hanoi after 14 days of incubation based on gas chromatography mass spectrometry analysis. To the best of our knowledge, reports on polycyclic aromatic hydrocarbon and phenol degradation by biofilm-forming yeasts are limited. The results obtained indicate that the biofilm formed by multiple yeast strains may considerably increase the degradation efficiency of aromatic hydrocarbon compounds, and may lead to a new approach for eliminating petroleum oil-contaminated water in Vietnam.

  18. 污水处理过程中苯系物和氯代烃三相分布规律%Distributions of BTEX and Chlorinated Hydrocarbons in Three Phases During Wastewater Treatment Processing

    Institute of Scientific and Technical Information of China (English)

    王琨; 杨俊晨; 黄丽坤; 高娜; 赵庆良

    2012-01-01

    为研究污水处理过程中曝气对苯系物中苯、甲苯和二甲苯以及氯代烃中三氯甲烷、四氯化碳、三氯乙烯和四氯乙烯去除的影响,设计了2个反应器,模拟污水处理过程,一个为活性污泥反应器,另一个为没有活性污泥的对照反应器.结果表明,在液相中,30.6%的TOC未经微生物降解而直接因曝气逸散到气相.苯系物的逸散比例达到了100%;三氯甲烷、四氯化碳、三氯乙烯和四氯乙烯的逸散比例分别为27.5%、39.0%、42.4%和38.5%.同时利用密闭水箱研究了生物处理单元中苯系物和氯代烃三相分布规律.在厌氧阶段,固相中苯、甲苯、二甲苯、三氯甲烷、四氯化碳、三氯乙烯和四氯乙烯占总量比例分别为38.7%、43.6%、38.0%、28.8%、24.3%、15.3%和20.5%.在曝气阶段,苯系物全部被去除,氯代烃总量略有下降.二沉池阶段,固相中三氯甲烷、四氯化碳、三氯乙烯、四氯乙烯占总质量的比例分别为5.2%、20.1%、6.8%和0%.%In order to investigate the influence of aeration on removal of BTEX ( benzene, toluene, xylene) and chlorinated hydrocarbons ( chloroform, carbon tetrachloride, trichloroethylene, tetrachloroethylene) during wastewater treatment processing, two lab-scale parallel reactors with and without activated sludge were designed to simulate wastewater treatment processing. The results indicated that 30. 6% of TOC in the liquid phase volatilized during aeration without microbial decomposition. The volatilization ratio of BTEX reached 100% , and the ratios of chloroform, carbon tetrachloride, trichloroethylene and tetrachloroethylene were 27.5% , 39.0% , 42.4% and 38.5% , respectively. At the same time, a dedicated tank was used to study the distribution of BTEX and chlorinated hydrocarbons in the three phases. Under the anaerobic condition, the percentages of benzene, toluene, xylene, chloroform, carbon tetrachloride, trichloroethylene

  19. Natural Attenuation Mechanism and Capability of Chlorinated Hydrocarbons in Shallow Groundwater in a Study Area in Shanghai%上海某污染场地浅层地下水中氯代烃自然降解机制及能力研究

    Institute of Scientific and Technical Information of China (English)

    郭琳

    2013-01-01

    自然衰减修复技术(Natural Attenuation remedy)是目前控制浅层地下水氯代烃污染比较可行的技术之一,其能否成功应用的关键在于证实在天然条件下是否存在氯代烃生物降解可能性及生物降解程度是否能满足场地的修复目标.针对上海某污染场地的浅层地下水氯代烃污染在自然条件下生物降解的机制进行了探讨,并对该场地氯代烃污染自然衰减能力进行了定性评价,以及利用归一化方法计算了场地内1,1,1-三氯乙烷的生物降解速率常数为0.032a-1,说明浅层地下水中的1,1,1-三氯乙烷存在天然生物降解,但降解速率比较缓慢,可采用人工加强自然衰减的方式对该场地进行修复.%Natural Attenuation Remedy is an effective and feasible technology for controlling the shallow groundwater chlorinated hydrocarbons contamination,the key of this technology is to verify the existence of biological degradation under the natural conditions,and determine whether the degradation can meet the remediation target levet.The mechanism of natural attenuation in groundwater of a study area in Shanghai was discussed,and the capacity of natural attenuation was also evaluated qualitatively.The calculated biological degradation rate of l,l,l-trichloroethane of this site is 0.032 a-1,which indicated the sufficient evidence of natural attenuation,but the degradation velocity is relatively slow.The natural attenuation process can be enhanced by some artificial measures.

  20. 挥发性氯代烃在土壤中的吸附行为研究进展%A REVIEW OF STUDIES ON SORPTION BEHAVIORS OF VOLATILE CHLORINATED HYDROCARBONS IN NATURAL SOIL

    Institute of Scientific and Technical Information of China (English)

    刘锐; 孟凡勇; 文晓刚; 陈吕军; 张永明

    2012-01-01

    挥发性氯代烃(Volatile chlorinated hydrocarbons,VCHs)是工业污染场地的常见污染物,在非饱和带存在于土壤气相、水相、固相或以高密度非水相液体(Dense non-aqueous phase liquids,DNAPL)的形式存在,形成一个动态平衡系统.土壤对VCHs的吸附不仅影响土壤中的污染物浓度,而且极大地影响VCHs的迁移转化行为.根据VCHs在土壤中的吸附机制,可以对土壤中的VCHs浓度进行预测,优化各种模型参数,指导污染修复及管理工作.本文总结了VCHs在非饱和带土壤中的相间分配特征,吸附机制及其影响因素,特别探讨了土壤有机碳、矿物及水分对吸附的影响,提出了当前研究中存在的问题,并对将来研究进行了展望.%Volatile chlorinated hydrocarbons (VCHs) are common pollutants in industrial polluted sites, existing in aqueous phase, gaseous phase, solid phase or the form of dense non-aqueous phase liquids ( DNAPL) , in unsaturated zones of the soil, forming a dynamic equilibrium system. The sorption of VCHs by the soil not only influences concentration of the pollutants in the soil, but also affects substantially migration and fate of VCHs. Understanding the mechanisms of VCHs sorption by the soil may help predict their concentrations in the soil, optimize the parameters of pertinent models, and guide remediation and management of the contaminated soil. A review is presented to summarize characteristics of the distribution of VCHs between these phases in soils of unsaturated zones, their sorption mechanisms as well as their affecting factors, and to elaborate in particular influences of soil organic carbon, minerals, and soil water on their sorption. Meanwhile, existent problems are pointed out in the current researches and an outlook is described of the future researches.

  1. Thraustochytrid protists degrade hydrocarbons

    Digital Repository Service at National Institute of Oceanography (India)

    Raikar, M.T.; Raghukumar, S.; Vani, V.; David, J.J.; Chandramohan, D.

    # For correspondence. E-mail: raghu@csnio.ren.nic.in INDIAN J MAR. SCI., VOL. 30, SEPTEMBER 2001 140 sample, four replicates of four dilutions each, namely 20, 10, 5 and 2.5 ml were added to sterile, flat- bottomed, wide-mouthed, screw-capped bottles (total...

  2. Deep Sequencing of Myxilla (Ectyomyxilla) methanophila, an Epibiotic Sponge on Cold-Seep Tubeworms, Reveals Methylotrophic, Thiotrophic, and Putative Hydrocarbon-Degrading Microbial Associations

    KAUST Repository

    Arellano, Shawn M.

    2012-10-11

    The encrusting sponge Myxilla (Ectyomyxilla) methanophila (Poecilosclerida: Myxillidae) is an epibiont on vestimentiferan tubeworms at hydrocarbon seeps on the upper Louisiana slope of the Gulf of Mexico. It has long been suggested that this sponge harbors methylotrophic bacteria due to its low δ13C value and high methanol dehydrogenase activity, yet the full community of microbial associations in M. methanophila remained uncharacterized. In this study, we sequenced 16S rRNA genes representing the microbial community in M. methanophila collected from two hydrocarbon-seep sites (GC234 and Bush Hill) using both Sanger sequencing and next-generation 454 pyrosequencing technologies. Additionally, we compared the microbial community in M. methanophila to that of the biofilm collected from the associated tubeworm. Our results revealed that the microbial diversity in the sponges from both sites was low but the community structure was largely similar, showing a high proportion of methylotrophic bacteria of the genus Methylohalomonas and polycyclic aromatic hydrocarbon (PAH)-degrading bacteria of the genera Cycloclasticus and Neptunomonas. Furthermore, the sponge microbial clone library revealed the dominance of thioautotrophic gammaproteobacterial symbionts in M. methanophila. In contrast, the biofilm communities on the tubeworms were more diverse and dominated by the chemoorganotrophic Moritella at GC234 and methylotrophic Methylomonas and Methylohalomonas at Bush Hill. Overall, our study provides evidence to support previous suggestion that M. methanophila harbors methylotrophic symbionts and also reveals the association of PAH-degrading and thioautotrophic microbes in the sponge. © 2012 Springer Science+Business Media New York.

  3. Molecular application for identification of polycyclic aromatic hydrocarbons degrading bacteria (PAHD) species isolated from oil polluted soil in Dammam, Saud Arabia.

    Science.gov (United States)

    Ibrahim, Mohamed M; Al-Turki, Ameena; Al-Sewedi, Dona; Arif, Ibrahim A; El-Gaaly, Gehan A

    2015-09-01

    Soil contamination with petroleum hydrocarbon products such as diesel and engine oil is becoming one of the major environmental problems. This study describes hydrocarbons degrading bacteria (PHAD) isolated from long-standing petrol polluted soil from the eastern region, Dammam, Saudi Arabia. The isolated strains were firstly categorized by accessible shape detection, physiological and biochemistry tests. Thereafter, a technique established on the sequence analysis of a 16S rDNA gene was used. Isolation of DNA from the bacterial strains was performed, on which the PCR reaction was carried out. Strains were identified based on 16S rDNA sequence analysis, As follows amplified samples were spontaneously sequenced automatically and the attained results were matched to open databases. Among the isolated bacterial strains, S1 was identified as Staphylococcus aureus and strain S1 as Corynebacterium amycolatum. PMID:26288572

  4. Polycyclovorans algicola gen. nov., sp. nov., an aromatic-hydrocarbon-degrading marine bacterium found associated with laboratory cultures of marine phytoplankton.

    Science.gov (United States)

    Gutierrez, Tony; Green, David H; Nichols, Peter D; Whitman, William B; Semple, Kirk T; Aitken, Michael D

    2013-01-01

    A strictly aerobic, halotolerant, rod-shaped bacterium, designated strain TG408, was isolated from a laboratory culture of the marine diatom Skeletonema costatum (CCAP1077/1C) by enrichment with polycyclic aromatic hydrocarbons (PAHs) as the sole carbon source. 16S rRNA gene sequence analysis placed this organism within the order Xanthomonadales of the class Gammaproteobacteria. Its closest relatives included representatives of the Hydrocarboniphaga-Nevskia-Sinobacter clade (<92% sequence similarity) in the family Sinobacteraceae. The strain exhibited a narrow nutritional spectrum, preferring to utilize aliphatic and aromatic hydrocarbon compounds and small organic acids. Notably, it displayed versatility in degrading two- and three-ring PAHs. Moreover, catechol 2,3-dioxygenase activity was detected in lysates, indicating that this strain utilizes the meta-cleavage pathway for aromatic compound degradation. Cells produced surface blebs and contained a single polar flagellum. The predominant isoprenoid quinone of strain TG408 was Q-8, and the dominant fatty acids were C(16:0), C(16:1) ω7c, and C(18:1) ω7c. The G+C content of the isolate's DNA was 64.3 mol% ± 0.34 mol%. On the basis of distinct phenotypic and genotypic characteristics, strain TG408 represents a novel genus and species in the class Gammaproteobacteria for which the name Polycyclovorans algicola gen. nov., sp. nov., is proposed. Quantitative PCR primers targeting the 16S rRNA gene of this strain were developed and used to show that this organism is found associated with other species of marine phytoplankton. Phytoplankton may be a natural biotope in the ocean where new species of hydrocarbon-degrading bacteria await discovery and which contribute significantly to natural remediation processes. PMID:23087039

  5. Bioremediation of coastal areas 5 years after the Nakhodka oil spill in the Sea of Japan: isolation and characterization of hydrocarbon-degrading bacteria

    International Nuclear Information System (INIS)

    Five years after the 1997 Nakhodka oil spill in the Sea of Japan, seven bacterial strains capable of utilizing the heavy oil spilled from the Nakhodka Russian oil tanker were isolated from three coastal areas (namely Katano Seashore of Fukui Prefecture, Osawa and Atake seashores of Ishikawa Prefecture) and the Nakhodka Russian oil tanker after a 5-year bioremediation process. All bacterial strains isolated could utilize long-chain-length alkanes efficiently, but not aromatic, and all of them were able to grow well on heavy oil. Using 16S rDNA sequencing, most of the strains were affiliated to Pseudomonas aeruginosa. Comparing between the year 1997 (at the beginning of bioremediation process) and the year 2001 (after 5 years of bioremediation), there was no significant change in morphology and size of hydrocarbon-degrading bacteria during the 5-year bioremediation. Scanning and transmission electron microscopic observations revealed that a large number of hydrocarbon- degrading bacteria still existed in the sites consisting of a variety of morphological forms of bacteria, such as coccus (Streptococcus and Staphylococcus) and bacillus (Streptobacillus). On the application of bioremediation processes on the laboratory-scale, laboratory microcosm experiments (containing seawater, beach sand, and heavy oil) under aerobic condition by two different treatments (i.e., placed inside the building and outside the building) were established for bioremediation of heavy oil to investigate the significance of the role of hydrocarbon-degrading bacteria on them. There was no significant bacterial activity differentiation in the two treatments, and removal of heavy oil by hydrocarbon degrading bacteria in the outside building was slightly greater than that in the inside building. The values of pH, Eh, EC, and dissolved oxygen (DO) in two treatments indicated that the bioremediation process took place under aerobic conditions (DO: 1-6 mg/l; Eh: 12-300 mV) and neutral

  6. Screening of a Hydrocarbon-degrading Bacterial Group and Study on Its Degrading Conditions%石油烃降解混合菌的筛选及其降解条件研究

    Institute of Scientific and Technical Information of China (English)

    刘其友; 宗明月; 张云波; 赵东风; 赵朝成

    2013-01-01

    5 highly efficient hydrocarbon-degrading mixed bacteria were. obtained from petroleum-contaminated samples of Karamay, Xinjiang by the traditional method of enrichment and isolation, and it was found that KL9-1 group has a wide temperature tolerance range and higher hydrocarbon degrading ability. The degradation rate of thin oil and heavy oil was up to 43.27% and 20.09% respectively through 7d at 45 ℃. The environmental factors on the degradation of petroleum hydrocarbon effect of KL9-1 group were studied using single factor test. Experimental results indicated that the inoculums amount of KL9-1, initial concentration of petroleum hydrocarbons, initial pH value, shaking speed and adding amount of surfactant can affect the degradation efficiency of petroleum hydrocarbon. The degradation rate of thin oil and heavy oil was up to 62.49% and 40.36% respectively at 35 ℃ under the conditions of inoculums amount 6.0%, initial concentration of petroleum hydrocarbons 1.5%, initial pH value 7.5, rotation speed 120 r/min and adding 200 mg/kg Tween80.%对采集克拉玛依地区的部分石油污染样品进行了富集分离,得到了5组石油烃高效降解混合菌,其中混合菌KL9-1对温度的耐受范围最宽,并且石油烃的降解效率最高.该混合菌在45℃的条件下,通过7d的降解,稀油的降解率达到43.27%,稠油的降解率达到20.09%.利用单因素试验考察环境因素对混合菌KL9-1降解石油烃的影响,结果表明混合菌KL9-1的接种量、石油烃初始浓度、初始pH、摇床转速、表面活性剂的添加都会影响石油烃的降解效果,在35℃的条件下,当接种量6.0%、石油烃初始浓度1.5%、初始pH 7.5、摇床转速120 r/min及添加200 mg/kg Tween80表面活性剂时,稀油和稠油的降解率都达到最高,其中稀油的降解率可以达到62.49%,稠油的降解率达到40.36%.

  7. Chlorinated, brominated, and perfluorinated compounds, polycyclic aromatic hydrocarbons and trace elements in livers of sea otters from California, Washington, and Alaska (USA), and Kamchatka (Russia)

    Science.gov (United States)

    Kannan, K.; Moon, H.-B.; Yun, S.-H.; Agusa, T.; Thomas, N.J.; Tanabe, S.

    2008-01-01

    Concentrations of organochlorine pesticides (DDTs, HCHs, and chlordanes), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs), perfluorinated compounds (PFCs), and 20 trace elements were determined in livers of 3- to 5-year old stranded sea otters collected from the coastal waters of California, Washington, and Alaska (USA) and from Kamchatka (Russia). Concentrations of organochlorine pesticides, PCBs, and PBDEs were high in sea otters collected from the California coast. Concentrations of DDTs were 10-fold higher in California sea otters than in otters from other locations; PCB concentrations were 5-fold higher, and PBDE concentrations were 2-fold higher, in California sea otters than in otters from other locations. Concentrations of PAHs were higher in sea otters from Prince William Sound than in sea otters from other locations. Concentrations of several trace elements were elevated in sea otters collected from California and Prince William Sound. Elevated concentrations of Mn and Zn in sea otters from California and Prince William Sound were indicative of oxidative stress-related injuries in these two populations. Concentrations of all of the target compounds, including trace elements, that were analyzed in sea otters from Kamchatka were lower than those found from the US coastal locations. ?? The Royal Society of Chemistry.

  8. Treatment of hydrocarbon-rich wastewater using oil degrading bacteria and phototrophic microorganisms in rotating biological contactor: Effect of N:P ratio

    International Nuclear Information System (INIS)

    Treatment of hydrocarbon-rich industrial wastewater in bioreactors using heterotrophic microorganisms is often associated with various operational problems. In this study, a consortium of phototrophic microorganisms and a bacterium is developed on the discs of a rotating biological contactor (RBC) for treatment of wastewater containing diesel oil. The reactor was fed with oil degrading bacterium, Burkholderia cepacia and oil tolerant phototrophic microorganisms. After biofilm formation and acclimatization to 0.6% (v/v) diesel, continuous-mode operation was initiated at 21 h hydraulic retention time (HRT). Residual diesel in the effluent was 0.003%. Advantages of this system include good total petroleum hydrocarbon (TPH) removal, no soluble carbon source requirement and good settleability of biosolids. Biofilm observations revealed the predominance of B. cepacia and cyanobacteria (Phormidium, Oscillatoria and Chroococcus). The N:P ratio affected the relative dominance of the phototrophic microorganisms and bacterial culture. This ratio was a critical factor in determining the performance efficiency of the reactor. At 21 h HRT and organic loading of 27.33 g TPH/m2 d, the N:P ratio 28.5:1 and 38:1 both yielded high and almost comparable TPH and COD removal efficiencies. This study presents a feasible technology for the treatment of hydrocarbon-rich wastewater from petrochemical industries and petroleum refineries

  9. Field observations on the variability of crude oil impact on indigenous hydrocarbon-degrading bacteria from sub-Antarctic intertidal sediments

    International Nuclear Information System (INIS)

    Oil pollution of the oceans has been a problem ever since man began to use fossil fuels. Biodegradation by naturally occurring populations of micro-organisms is a major mechanism for the removal of petroleum from the environment. To examine the effects of crude oil-pollution on intertidal bacteria, we repeated the same contamination experiments on nine different sub-Antarctic intertidal beaches using specifically built enclosures (PVC pipe, 15 cm in inner diameter and 30 cm in height). Despite the pristine environmental conditions, significant numbers of indigenous hydrocarbon-degrading bacteria were observed in all the studied beaches. Introduction of oil into these previously oil-free environments resulted in several orders of magnitude of increase in hydrocarbon-degrading micro-organisms within a few days in some of the studied sites but has no obvious effects on two others. The physical environment of the bacterial assemblage seems to play a major role in the biodegradation capacities. After 3 months of contamination, both remaining oil concentrations and biodegradation indexes differ strongly between the different stations. Thus, chemical and biological parameters reveal a strong heterogeneity of biodegradation capacities between the different sites. (Author)

  10. Transformation of iopamidol during chlorination.

    Science.gov (United States)

    Wendel, Friedrich M; Lütke Eversloh, Christian; Machek, Edward J; Duirk, Stephen E; Plewa, Michael J; Richardson, Susan D; Ternes, Thomas A

    2014-11-01

    The transformation of the iodinated X-ray contrast media (ICM) iopamidol, iopromide, iohexol, iomeprol, and diatrizoate was examined in purified water over the pH range from 6.5 to 8.5 in the presence of sodium hypochlorite, monochloramine, and chlorine dioxide. In the presence of aqueous chlorine, only iopamidol was transformed. All other ICM did not show significant reactivity, regardless of the oxidant used. Chlorination of iopamidol followed a second order reaction, with an observed rate constant of up to 0.87 M(-1) s(-1) (±0.021 M(-1) s(-1)) at pH 8.5. The hypochlorite anion was identified to be the reactive chlorine species. Iodine was released during the transformation of iopamidol, and was mainly oxidized to iodate. Only a small percentage (less than 2% after 24 h) was transformed to known organic iodinated disinfection byproducts (DBPs) of low molecular weight. Some of the iodine was still present in high-molecular weight DBPs. The chemical structures of these DBPs were elucidated via MSn fragmentation and NMR. Side chain cleavage was observed as well as the exchange of iodine by chlorine. An overall transformation pathway was proposed for the degradation of iopamidol. CHO cell chronic cytotoxicity tests indicate that chlorination of iopamidol generates a toxic mixture of high molecular weight DBPs (LC50 332 ng/μL).

  11. Accumulation and degradation of dead-end metabolites during treatment of soil contaminated with polycyclic aromatic hydrocarbons with five strains of white-rot fungi

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, B.E. [Centre for Chemistry and Chemical Engineering, Dept. of Biotechnology, Lund Univ. (Sweden); Henrysson, T. [Centre for Chemistry and Chemical Engineering, Dept. of Biotechnology, Lund Univ. (Sweden)

    1996-12-31

    The white-rot fungi Trametes versicolor PRL 572, Trametes versicolor MUCL 28407, Pleurotus ostreatus MUCL 29527, Pleurotus sajor-caju MUCL 29757 and Phanerochaete chrysosporium DSM 1556 were investigated for their ability to degrade the polycyclic aromatic hydrocarbons (PAH) anthracene, benz[a]anthracene and dibenz[a, h]anthracene in soil. The fungi were grown on wheat straw and mixed with artificially contaminated soil. The results of this study show that, in a heterogeneous soil environment, the fungi have different abilities to degrade PAH, with Trametes showing little or no accumulation of dead-end metabolites and Phanerochaete and Pleurotus showing almost complete conversion of anthracene to 9,10-anthracenedione. In contrast to earlier studies, Phanerochaete showed the ability to degrade the accumulated 9,10-anthracenedione while Pleurotus did not. This proves that, in a heterogeneous soil system, the PAH degradation pattern for white-rot fungi can be quite different from that in a controlled liquid system. (orig.)

  12. 多环芳烃的微生物降解机制研究进展%Research Progress on Microbial Degradation Mechanisms for Polycyclic Aromatic Hydrocarbons

    Institute of Scientific and Technical Information of China (English)

    王涛; 蓝慧; 田云; 卢向阳

    2016-01-01

    多环芳烃是环境中最常见且最难降解的有机污染物之一。通过微生物降解使环境中的多环芳烃低毒化或无毒化是当今环境修复的研究热点之一。以萘和菲为研究对象,论述了多环芳烃的微生物降解机制,并阐述了生命组学新技术在多环芳烃降解机制研究中的应用,为深入探讨多环芳烃的微生物降解及转化机制奠定了理论基础。%Polycyclic aromatic hydrocarbons(PAHs)are one of the common and the most refractory organic pollutants in the environment.Nowadays,low-toxicity or non-toxicity of PAHs by microbial degradation is one of the research highlights in the field of environmental remediation.In this paper,using naphthalene and phe-nanthrene as example,the microbial degradation mechanisms of PAHs are reviewed,and the application of“omics”technology in life science for research of microbial degradation of PAHs is summarized.The review lays a certain theoretical foundation for further exploring the microbial degradation and conversion mechanism for PAHs.

  13. Genome Sequence of Arenibacter algicola Strain TG409, a Hydrocarbon-Degrading Bacterium Associated with Marine Eukaryotic Phytoplankton.

    Science.gov (United States)

    Gutierrez, Tony; Whitman, William B; Huntemann, Marcel; Copeland, Alex; Chen, Amy; Kyrpides, Nikos; Markowitz, Victor; Pillay, Manoj; Ivanova, Natalia; Mikhailova, Natalia; Ovchinnikova, Galina; Andersen, Evan; Pati, Amrita; Stamatis, Dimitrios; Reddy, T B K; Ngan, Chew Yee; Chovatia, Mansi; Daum, Chris; Shapiro, Nicole; Cantor, Michael N; Woyke, Tanja

    2016-01-01

    Arenibacter algicola strain TG409 was isolated from Skeletonema costatum and exhibits the ability to utilize polycyclic aromatic hydrocarbons as sole sources of carbon and energy. Here, we present the genome sequence of this strain, which is 5,550,230 bp with 4,722 genes and an average G+C content of 39.7%. PMID:27491994

  14. Draft Genome Sequence of Pseudomonas sp. Strain 10-1B, a Polycyclic Aromatic Hydrocarbon Degrader in Contaminated Soil

    OpenAIRE

    Bello-Akinosho, Maryam; Adeleke, Rasheed; Swanevelder, Dirk; Thantsha, Mapitsi

    2015-01-01

    Pseudomonas sp. strain 10-1B was isolated from artificially polluted soil after selective enrichment. Its draft genome consists of several predicted genes that are involved in the hydroxylation of the aromatic ring, which is the rate-limiting step in the biodegradation of polycyclic aromatic hydrocarbons.

  15. Transcriptional profiling of genes involved in n-hexadecane compounds assimilation in the hydrocarbon degrading Dietzia cinnamea P4 strain

    NARCIS (Netherlands)

    Procopio, Luciano; Pereira e Silva, Michele de Cassia; van Elsas, Jan Dirk; Seldin, Lucy

    2013-01-01

    The petroleum-derived degrading Dietzia cinnamea strain P4 recently had its genome sequenced and annotated. This allowed employing the data on genes that are involved in the degradation of n-alkanes. To examine the physiological behavior of strain P4 in the presence of n-alkanes, the strain was grow

  16. Genome Sequence of Halomonas sp. Strain MCTG39a, a Hydrocarbon-Degrading and Exopolymeric Substance-Producing Bacterium

    OpenAIRE

    Gutierrez, Tony; Whitman, William B.; Huntemann, Marcel; Copeland, Alex; Chen, Amy; Kyrpides, Nikos; Markowitz, Victor; Pillay, Manoj; Ivanova, Natalia; Mikhailova, Natalia; Ovchinnikova, Galina; Andersen, Evan; Pati, Amrita; Stamatis, Dimitrios; Reddy, T. B. K.

    2015-01-01

    Halomonas sp. strain MCTG39a was isolated from coastal sea surface water based on its ability to utilize n-hexadecane. During growth in marine medium the strain produces an amphiphilic exopolymeric substance (EPS) amended with glucose, which emulsifies a variety of oil hydrocarbon substrates. Here, we present the genome sequence of this strain, which is 4,979,193 bp with 4,614 genes and an average G+C content of 55.0%.

  17. Genome Sequence of Halomonas sp. Strain MCTG39a, a Hydrocarbon-Degrading and Exopolymeric Substance-Producing Bacterium.

    Science.gov (United States)

    Gutierrez, Tony; Whitman, William B; Huntemann, Marcel; Copeland, Alex; Chen, Amy; Kyrpides, Nikos; Markowitz, Victor; Pillay, Manoj; Ivanova, Natalia; Mikhailova, Natalia; Ovchinnikova, Galina; Andersen, Evan; Pati, Amrita; Stamatis, Dimitrios; Reddy, T B K; Ngan, Chew Yee; Chovatia, Mansi; Daum, Chris; Shapiro, Nicole; Cantor, Michael N; Woyke, Tanja

    2015-01-01

    Halomonas sp. strain MCTG39a was isolated from coastal sea surface water based on its ability to utilize n-hexadecane. During growth in marine medium the strain produces an amphiphilic exopolymeric substance (EPS) amended with glucose, which emulsifies a variety of oil hydrocarbon substrates. Here, we present the genome sequence of this strain, which is 4,979,193 bp with 4,614 genes and an average G+C content of 55.0%. PMID:26184945

  18. Microbial diversity in methanogenic hydrocarbon-degrading enrichment cultures isolated from a water-flooded oil reservoir (Dagang oil field, China)

    Science.gov (United States)

    Jiménez, Núria; Cai, Minmin; Straaten, Nontje; Yao, Jun; Richnow, Hans H.; Krüger, Martin

    2015-04-01

    Microbial transformation of oil to methane is one of the main degradation processes taking place in oil reservoirs, and it has important consequences as it negatively affects the quality and economic value of the oil. Nevertheless, methane could constitute a recovery method of carbon from exhausted reservoirs. Previous studies combining geochemical and isotopic analysis with molecular methods showed evidence for in situ methanogenic oil degradation in the Dagang oil field, China (Jiménez et al., 2012). However, the main key microbial players and the underlying mechanisms are still relatively unknown. In order to better characterize these processes and identify the main microorganisms involved, laboratory biodegradation experiments under methanogenic conditions were performed. Microcosms were inoculated with production and injection waters from the reservoir, and oil or 13C-labelled single hydrocarbons (e.g. n-hexadecane or 2-methylnaphthalene) were added as sole substrates. Indigenous microbiota were able to extensively degrade oil within months, depleting most of the n-alkanes in 200 days, and producing methane at a rate of 76 ± 6 µmol day-1 g-1 oil added. They could also produce heavy methane from 13C-labeled 2-methylnaphthalene, suggesting that further methanogenesis may occur from the aromatic and polyaromatic fractions of Dagang reservoir fluids. Microbial communities from oil and 2-methyl-naphthalene enrichment cultures were slightly different. Although, in both cases Deltaproteobacteria, mainly belonging to Syntrophobacterales (e.g. Syntrophobacter, Smithella or Syntrophus) and Clostridia, mostly Clostridiales, were among the most represented taxa, Gammaproteobacteria could be only identified in oil-degrading cultures. The proportion of Chloroflexi, exclusively belonging to Anaerolineales (e.g. Leptolinea, Bellilinea) was considerably higher in 2-methyl-naphthalene degrading cultures. Archaeal communities consisted almost exclusively of representatives of

  19. 探究海绵铁/银脱氯还原降解二噁英的方法%Explore the Sponge Iron/Silver De-chlorination Method of Reduction Degradation of Dioxins

    Institute of Scientific and Technical Information of China (English)

    杨蒙蒙; 穆乃花

    2014-01-01

    以OCDF和12378-PeCDF为例,探究了海绵铁脱氯还原降解二英的方法。对比了超声、海绵铁+超声、海绵铁/银+超声三种处理二英的实验方法,并对海绵铁/银+超声处理方法中二英浓度、海绵铁投加量以及超声时间等条件进行了优化,探索海绵铁处理二英的方法。实验结果表明,在海绵铁/银+超声的体系条件下还不能脱氯还原降解二英,还需要做进一步深入的探究。%This paper,taking OCDF and 1 2378-PeCDF as example,explores the sponge iron reduction degrada-tion dioxin de-chlorination method as well as a comparison of ultrasound,sponge iron+ultrasound,sponge iron/Ag+ultrasonic three treatments dioxin experimental methods.And Optimization sponge/Ag+ultrasonic treatment conditions,concentration of dioxins treatment,sponge iron dosage and time ultrasound conditions were optimized to explore the sponge method of dioxin treatment.Experimental results show that the sponge iron/Ag+ultrasound sys-tem conditions can not restore degraded de-chlorination of dioxins,which needs further inquiry.

  20. 探究海绵铁/银脱氯还原降解二噁英的方法%Explore the Sponge Iron/Silver De-chlorination Method of Reduction Degradation of Dioxins

    Institute of Scientific and Technical Information of China (English)

    杨蒙蒙; 穆乃花

    2014-01-01

    This paper,taking OCDF and 1 2378-PeCDF as example,explores the sponge iron reduction degrada-tion dioxin de-chlorination method as well as a comparison of ultrasound,sponge iron+ultrasound,sponge iron/Ag+ultrasonic three treatments dioxin experimental methods.And Optimization sponge/Ag+ultrasonic treatment conditions,concentration of dioxins treatment,sponge iron dosage and time ultrasound conditions were optimized to explore the sponge method of dioxin treatment.Experimental results show that the sponge iron/Ag+ultrasound sys-tem conditions can not restore degraded de-chlorination of dioxins,which needs further inquiry.%以OCDF和12378-PeCDF为例,探究了海绵铁脱氯还原降解二英的方法。对比了超声、海绵铁+超声、海绵铁/银+超声三种处理二英的实验方法,并对海绵铁/银+超声处理方法中二英浓度、海绵铁投加量以及超声时间等条件进行了优化,探索海绵铁处理二英的方法。实验结果表明,在海绵铁/银+超声的体系条件下还不能脱氯还原降解二英,还需要做进一步深入的探究。

  1. Effect of birch (Betula spp.) and associated rhizoidal bacteria on the degradation of soil polyaromatic hydrocarbons, PAH-induced changes in birch proteome and bacterial community.

    Science.gov (United States)

    Tervahauta, Arja I; Fortelius, Carola; Tuomainen, Marjo; Akerman, Marja-Leena; Rantalainen, Kimmo; Sipilä, Timo; Lehesranta, Satu J; Koistinen, Kaisa M; Kärenlampi, Sirpa; Yrjälä, Kim

    2009-01-01

    Two birch clones originating from metal-contaminated sites were exposed for 3 months to soils (sand-peat ratio 1:1 or 4:1) spiked with a mixture of polyaromatic hydrocarbons (PAHs; anthracene, fluoranthene, phenanthrene, pyrene). PAH degradation differed between the two birch clones and also by the soil type. The statistically most significant elimination (p birch, the clearest positive effect being found with Betula pubescens clone on phenanthrene. PAHs and soil composition had rather small effects on birch protein complement. Three proteins with clonal differences were identified: ferritin-like protein, auxin-induced protein and peroxidase. Differences in planted and non-planted soils were detected in bacterial communities by 16S rRNA T-RFLP, and the overall bacterial community structures were diverse. Even though both represent complex systems, trees and rhizoidal microbes in combination can provide interesting possibilities for bioremediation of PAH-polluted soils.

  2. Study on Equilibrium Adsorption of Volatile Chlorinated Hydrocarbons on Humid Soils%挥发性氯代烃在湿润土壤中的平衡吸附研究

    Institute of Scientific and Technical Information of China (English)

    孟凡勇; 刘锐; 小林刚; 万梅; 余素林; 陈吕军

    2012-01-01

    吸附是挥发性氯代烃(volatile chlorinated hydrocarbons,VCHs)赋存于土壤的主要机制之一.开展动态吸附实验,研究了4种常见VCHs污染物在我国8种典型土壤中的吸附平衡关系.结果表明,土壤在干燥条件下对VCHs气体的吸附能力要远大于湿润条件,且随含水率的升高吸附能力急剧下降,在含水率达到10%以后土壤吸附量趋于稳定.湿润土壤对三氯乙烯(TCE)、四氯乙烯(PCE)、1,1,1-三氯乙烷(MC)气体的吸附等温线符合Henry型吸附等温式,而1,1,2-三氯乙烷(1,1,2-TCA)符合Freundlich模型.VCHs在湿润土壤中的吸附量总体上与土壤有机碳(soil organic carbon,SOC)含量呈正相关,且受SOC类型和化合物极性影响较大.弱极性的TCE、PCE在土壤中的吸附能力与SOC含量呈严格正相关,而极性的MC、1,1,2-TCA在黑土等高碳土壤中不仅与SOC含量有关,还受到SOC物质组成的影响.建立了TCE和PCE在湿润土壤中的平衡吸附量预测模型,预测值与实测值相关性良好(n=80,R2=0.98).%Adsorption is one of the principal mechanisms for soil contamination by volatile chlorinated hydrocarbons(VCHs).Dynamic adsorption experiments were carried out to study the equilibrium adsorption of four common VCHs pollutants onto eight typical soils in China.Results showed that dry soils had far greater adsorption capacity than humid soils.The soil adsorption capacity sharply decreased with the increase in the soil water content,and then reached a plateau as the water content rose to 10% or above.The adsorption isotherms of trichloroethylene(TCE),tetrachloroethylene(PCE) and 1,1,1-trichloroethane(MC) could be fitted with Henry's equation,while the adsorption isotherms of 1,1,2-trichloroethane(1,1,2-TCA) could be fitted with Freundlich model.The adsorption capacities of VCHs on humid soils were principally influenced by the content of soil organic carbon(SOC),but sometimes also

  3. The hydrogen concentration as parameter to identify natural attenuation processes of volatile chlorinated hydrocarbons in ground water; Die Wasserstoffkonzentration als Parameter zur Identifizierung des natuerlichen Abbaus von leichtfluechtigen Chlorkohlenwasserstoffen (LCKW) im Grundwasser

    Energy Technology Data Exchange (ETDEWEB)

    Alter, M.D.

    2006-06-15

    In this study, the hydrogen concentration as parameter to identify natural attenuation processes of volatile chlorinated hydrocarbons was investigated. The currently accepted and recommended bubble strip method for hydrogen sampling was optimized, and a storage method for hydrogen samples was developed. Furthermore batch experiments with a dechlorinating mixed culture and pure cultures were carried out to study H{sub 2}-concentrations of competing redox processes. The extraction of hydrogen from ground water was optimized by a reduced inlet diameter of the usually applied gas sampling bulbs, allowing a maximal turbulent ow and gas transfer. With a gas volume of 10 ml and flow rates of 50 to 140 ml/min, the course of extraction almost followed the theoretical course of equilibration. At flow rates > 100 ml/min a equilibrium of 98% was achieved within 20 min. Until recently it was generally accepted that hydrogen samples can be stored only for 2 hours and therefore have to be analyzed immediately in the eld. Here, it was shown that eld samples can be stored for 1-3 days until analysis. For the dechlorination of tetrachloroethene (PCE), a hydrogen threshold concentration of 1-2 nM was found with the dechlorinating mixed culture as well as with a pure culture of Sulfurospirillum multivorans in combination with another pure culture Methanosarcina mazei. No dechlorination was detectable below this concentration. With the dechlorinating mixed culture, this finding is valid for all successive dechlorination steps until ethene. The hydrogen threshold concentration for denitrification were below the detection limit of 0,2 nM with the dechlorinating mixed culture. A threshold concentration of 3,1-3,5 nM was found for sulphate reduction and a threshold of 7-9 nM H{sub 2} for hydrogenotrophic methanogenesis. This implies that the natural dechlorination at contaminated sites is preferred to competing processes like sulphate reduction and methanogenesis. The threshold

  4. Effect of birch (Betula spp.) and associated rhizoidal bacteria on the degradation of soil polyaromatic hydrocarbons, PAH-induced changes in birch proteome and bacterial community

    Energy Technology Data Exchange (ETDEWEB)

    Tervahauta, Arja I. [Department of Biosciences, University of Kuopio, P.O. Box 1627, FIN-70211 Kuopio (Finland)], E-mail: arja.tervahauta@uku.fi; Fortelius, Carola [EVTEK University of Applied Sciences, Vantaa (Finland); Tuomainen, Marjo [Department of Biosciences, University of Kuopio, P.O. Box 1627, FIN-70211 Kuopio (Finland); Akerman, Marja-Leena [EVTEK University of Applied Sciences, Vantaa (Finland); Rantalainen, Kimmo [Department of Biosciences, University of Kuopio, P.O. Box 1627, FIN-70211 Kuopio (Finland); Sipilae, Timo [Department of Biological and Environmental Sciences, University of Helsinki (Finland); Lehesranta, Satu J.; Koistinen, Kaisa M.; Kaerenlampi, Sirpa [Department of Biosciences, University of Kuopio, P.O. Box 1627, FIN-70211 Kuopio (Finland); Yrjaelae, Kim [Department of Biological and Environmental Sciences, University of Helsinki (Finland)

    2009-01-15

    Two birch clones originating from metal-contaminated sites were exposed for 3 months to soils (sand-peat ratio 1:1 or 4:1) spiked with a mixture of polyaromatic hydrocarbons (PAHs; anthracene, fluoranthene, phenanthrene, pyrene). PAH degradation differed between the two birch clones and also by the soil type. The statistically most significant elimination (p {<=} 0.01), i.e. 88% of total PAHs, was observed in the more sandy soil planted with birch, the clearest positive effect being found with Betula pubescens clone on phenanthrene. PAHs and soil composition had rather small effects on birch protein complement. Three proteins with clonal differences were identified: ferritin-like protein, auxin-induced protein and peroxidase. Differences in planted and non-planted soils were detected in bacterial communities by 16S rRNA T-RFLP, and the overall bacterial community structures were diverse. Even though both represent complex systems, trees and rhizoidal microbes in combination can provide interesting possibilities for bioremediation of PAH-polluted soils. - Birch can enhance degradation of PAH compounds in the rhizosphere.

  5. Analysis of defence systems and a conjugative IncP-1 plasmid in the marine polyaromatic hydrocarbons-degrading bacterium Cycloclasticus sp. 78-ME.

    Science.gov (United States)

    Yakimov, Michail M; Crisafi, Francesca; Messina, Enzo; Smedile, Francesco; Lopatina, Anna; Denaro, Renata; Pieper, Dietmar H; Golyshin, Peter N; Giuliano, Laura

    2016-08-01

    Marine prokaryotes have evolved a broad repertoire of defence systems to protect their genomes from lateral gene transfer including innate or acquired immune systems and infection-induced programmed cell suicide and dormancy. Here we report on the analysis of multiple defence systems present in the genome of the strain Cycloclasticus sp. 78-ME isolated from petroleum deposits of the tanker 'Amoco Milford Haven'. Cycloclasticus are ubiquitous bacteria globally important in polyaromatic hydrocarbons degradation in marine environments. Two 'defence islands' were identified in 78-ME genome: the first harbouring CRISPR-Cas with toxin-antitoxin system, while the second was composed by an array of genes for toxin-antitoxin and restriction-modification proteins. Among all identified spacers of CRISPR-Cas system only seven spacers match sequences of phages and plasmids. Furthermore, a conjugative plasmid p7ME01, which belongs to a new IncP-1θ ancestral archetype without any accessory mobile elements was found in 78-ME. Our results provide the context to the co-occurrence of diverse defence mechanisms in the genome of Cycloclasticus sp. 78-ME, which protect the genome of this highly specialized PAH-degrader. This study contributes to the further understanding of complex networks established in petroleum-based microbial communities. PMID:27345842

  6. Bioremediation of multi-polluted soil by spent mushroom (Agaricus bisporus) substrate: Polycyclic aromatic hydrocarbons degradation and Pb availability.

    Science.gov (United States)

    García-Delgado, Carlos; Yunta, Felipe; Eymar, Enrique

    2015-12-30

    This study investigates the effect of three spent Agaricus bisporus substrate (SAS) application methods on bioremediation of soil multi-polluted with Pb and PAH from close to a shooting range with respect natural attenuation (SM). The remediation treatments involve (i) use of sterilized SAS to biostimulate the inherent soil microbiota (SSAS) and two bioaugmentation possibilities (ii) its use without previous treatment to inoculate A. bisporus and inherent microbiota (SAS) or (iii) SAS sterilization and further A. bisporus re-inoculation (Abisp). The efficiency of each bioremediation microcosm was evaluated by: fungal activity, heterotrophic and PAH-degrading bacterial population, PAH removal, Pb mobility and soil eco-toxicity. Biostimulation of the native soil microbiology (SSAS) achieved similar levels of PAH biodegradation as SM and poor soil detoxification. Bioaugmented microcosms produced higher PAH removal and eco-toxicity reduction via different routes. SAS increased the PAH-degrading bacterial population, but lowered fungal activity. Abisp was a good inoculum carrier for A. bisporus exhibiting high levels of ligninolytic activity, the total and PAH-degrading bacteria population increased with incubation time. The three SAS applications produced slight Pb mobilization (<0.3%). SAS sterilization and further A. bisporus re-inoculation (Abisp) proved the best application method to remove PAH, mainly BaP, and detoxify the multi-polluted soil. PMID:26188871

  7. Bioremediation of multi-polluted soil by spent mushroom (Agaricus bisporus) substrate: Polycyclic aromatic hydrocarbons degradation and Pb availability.

    Science.gov (United States)

    García-Delgado, Carlos; Yunta, Felipe; Eymar, Enrique

    2015-12-30

    This study investigates the effect of three spent Agaricus bisporus substrate (SAS) application methods on bioremediation of soil multi-polluted with Pb and PAH from close to a shooting range with respect natural attenuation (SM). The remediation treatments involve (i) use of sterilized SAS to biostimulate the inherent soil microbiota (SSAS) and two bioaugmentation possibilities (ii) its use without previous treatment to inoculate A. bisporus and inherent microbiota (SAS) or (iii) SAS sterilization and further A. bisporus re-inoculation (Abisp). The efficiency of each bioremediation microcosm was evaluated by: fungal activity, heterotrophic and PAH-degrading bacterial population, PAH removal, Pb mobility and soil eco-toxicity. Biostimulation of the native soil microbiology (SSAS) achieved similar levels of PAH biodegradation as SM and poor soil detoxification. Bioaugmented microcosms produced higher PAH removal and eco-toxicity reduction via different routes. SAS increased the PAH-degrading bacterial population, but lowered fungal activity. Abisp was a good inoculum carrier for A. bisporus exhibiting high levels of ligninolytic activity, the total and PAH-degrading bacteria population increased with incubation time. The three SAS applications produced slight Pb mobilization (soil.

  8. On chlorinated hydrocarbons in the Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Sarkar, A.; SenGupta, R.

    The data available on the distribution of organochlorine compounds such as DDT and its metabolites, aldrin, dieldrin, endrin, isomers of HCH and the PCBs in the sediments, water, zooplankton, fish and seals from the Indian Ocean is reviewed. High...

  9. Study of the mineralization effect on the distribution of lipids in sediments from the Cretan Sea: Evidence for hydrocarbon degradation and starvation stress

    Science.gov (United States)

    Polymenakou, Paraskevi N.; Tselepides, Anastasios; Stephanou, Euripides G.

    2005-11-01

    Sedimentary diagenetic processes alter the composition and distribution of different lipid compounds. In the present study alterations mediated by microbial communities were investigated along a bathymetric gradient (100 m at 35°23'N-25°09'E, 617 m at 35°33'N-25°08'E, 1494 m at 35°44'N-25°08'E) over the continental margin of northern Crete (Greece, Eastern Mediterranean Sea). Bacterial abundances and distribution were studied using phospholipid linked fatty acids (PLFA), in the range of C 8-C 22, released from intact phospholipids. Lipid components (aliphatic hydrocarbons, free fatty acids, glycerides and glycolipids) were studied over a 2-month incubation period. Carbon mineralization rates at all stations indicated an uneven distribution of active aerobic bacteria with values decreasing towards the deeper stations. PLFA homologue profiles denoted that aerobic gram negative and sulfur oxidizing bacteria dominated microbial communities while the anaerobic, gram positive and sulfate reducing bacteria occurred only in traces. The n-alkane (NA) composition revealed a strong predominance of homologues with odd carbon numbers suggesting an important terrestrial contribution to the sediments. The estimated descriptive ratios of NA, the sum of short chain NA (C 15-C 20) and long chain NA (C 21-C 36) to 17 α( H),21 β( H)-C 30-hopane, before and after a two-month incubation period, indicated the occurrence of hydrocarbon degradation processes. Increased ratios of saturated to unsaturated fatty acids were also recorded after the incubation indicating the starvation of bacterial communities by the end of the experiments.

  10. Electrodeposited nickel(3) aluminide base intermetallic coatings and their resistance to high temperature degradation in hydrocarbon cracking environments

    Science.gov (United States)

    Liu, Haifeng

    This research was aimed at developing novel Ni-A1 base intermetallic coatings to protect commercial Fe-Ni-Cr tube alloys from severe corrosive degradation at high temperatures. These alloys are widely used in petrochemical, chemical, and energy conversion industries. The coating process and coating evaluation were the two main aspects of this investigation. A two-step coating processing has been successfully developed to in situ apply pure and CeO2-modified Ni3Al intermetallic coatings onto Fe-Ni-Cr substrates. The process consists of the electrodeposition of Ni-Al and Ni-Al-CeO2 composite coatings from a Watt's nickel bath containing Al and CeO2 particles via a cost-effective electroplating technique and an annealing treatment of the as-plated coatings. It was found that the deposition of Al particles obeyed a Guglielmi model, and that REO particles interfered significantly with the deposition of Al particles. The long-term resistance of pure and CeO2-modified Ni 3A1 coatings to cyclic oxidation, carburization, coke formation, and metal dusting was evaluated in flowing dry air, 2 % CH4-H 2, and CO-H2-H2O respectively. Due to the high porosity, pure and CeO2-dispersed Ni3Al coatings exhibited poor resistance to cyclic oxidation at 850°C. CeO2 improved the spallation resistance of the Ni3Al base coatings during cyclic oxidation at 1050°C. CeO2-dispersed Ni3Al coatings showed better carburization resistance, particularly at 1050°C. Ni 3A1-based coatings. Those CeO2-dispersed were susceptible to coke formation and metal dusting at 650°C. Pre-oxidation improved the resistance of Ni3Al-based coatings to coke formation and metal dusting at 650°C, but the effectiveness depended on the integrity of the induced alumina scale. Special attention was paid to several aspects of coating degradation. These aspects included microstructure changes, degradation mechanisms, coating/substrate interdiffusion, effect of corrosive atmosphere, and effect of CeO2 on coating

  11. Stable carbon isotopic compositions of intact polar lipids reveal complex carbon flow patterns among hydrocarbon degrading microbial communities at the Chapopote asphalt volcano

    Science.gov (United States)

    Schubotz, Florence; Lipp, Julius S.; Elvert, Marcus; Hinrichs, Kai-Uwe

    2011-08-01

    Seepage of asphalt forms the basis of a cold seep system at 3000 m water depth at the Chapopote Knoll in the southern Gulf of Mexico. Anaerobic microbial communities are stimulated in the oil-impregnated sediments as evidenced by the presence of intact polar membrane lipids (IPLs) derived from archaea and Bacteria at depths up to 7 m below the seafloor. Detailed investigation of stable carbon isotope composition (δ 13C) of alkyl and acyl moieties derived from a range of IPL precursors with distinct polar head groups resolved the complexity of carbon metabolisms and utilization of diverse carbon sources by uncultured microbial communities. In surface sediments most of the polar lipid-derived fatty acids with phosphatidylethanolamine (PE), phosphatidylglycerol (PG) and diphosphatidylglycerol (DPG) head groups could be tentatively assigned to autotrophic sulfate-reducing bacteria, with a relatively small proportion involved in the anaerobic oxidation of methane. Derivatives of phosphatidyl-( N)-methylethanolamine (PME) were abundant and could be predominantly assigned to heterotrophic oil-degrading bacteria. Archaeal IPLs with phosphate-based hydroxyarchaeols and diglycosidic glyceroldibiphytanylglyceroltetraethers (GDGTs) were assigned to methanotrophic archaea of the ANME-2 and ANME-1 cluster, respectively, whereas δ 13C values of phosphate-based archaeols and mixed phosphate-based and diglycosidic GDGTs point to methanogenic archaea. At a 7 m deep sulfate-methane transition zone that is linked to the upward movement of gas-laden petroleum, a distinct increase in abundance of archaeal IPLs such as phosphate-based hydroxyarchaeols and diglycosidic archaeol and GDGTs is observed; their δ 13C values are consistent with their origin from both methanotrophic and methanogenic archaea. This study reveals previously hidden, highly complex patterns in the carbon-flow of versatile microbial communities involved in the degradation of heavy oil including hydrocarbon gases

  12. Integration of stable carbon isotope, microbial community, dissolved hydrogen gas, and 2HH2O tracer data to assess bioaugmentation for chlorinated ethene degradation in fractured rocks

    Science.gov (United States)

    Révész, Kinga M.; Lollar, Barbara Sherwood; Kirshtein, Julie D.; Tiedeman, Claire R.; Imbrigiotta, Thomas E.; Goode, Daniel J.; Shapiro, Allen M.; Voytek, Mary A.; Lancombe, Pierre J.; Busenberg, Eurybiades

    2014-01-01

    An in situ bioaugmentation (BA) experiment was conducted to understand processes controlling microbial dechlorination of trichloroethene (TCE) in groundwater at the Naval Air Warfare Center (NAWC), West Trenton, NJ. In the BA experiment, an electron donor (emulsified vegetable oil and sodium lactate) and a chloro-respiring microbial consortium were injected into a well in fractured mudstone of Triassic age. Water enriched in 2H was also injected as a tracer of the BA solution, to monitor advective transport processes. The changes in concentration and the δ13C of TCE, cis-dichloroethene (cis-DCE), and vinyl chloride (VC); the δ2H of water; changes in the abundance of the microbial communities; and the concentration of dissolved H2 gas compared to pre- test conditions, provided multiple lines of evidence that enhanced biodegradation occurred in the injection well and in two downgradient wells. For those wells where the biodegradation was stimulated intensively, the sum of the molar chlorinated ethene (CE) concentrations in post-BA water was higher than that of the sum of the pre-BA background molar CE concentrations. The concentration ratios of TCE/(cis-DCE + VC) indicated that the increase in molar CE concentration may result from additional TCE mobilized from the rock matrix in response to the oil injection or due to desorption/diffusion. The stable carbon isotope mass-balance calculations show that the weighted average 13C isotope of the CEs was enriched for around a year compared to the background value in a two year monitoring period, an effective indication that dechlorination of VC was occurring. Insights gained from this study can be applied to efforts to use BA in other fractured rock systems. The study demonstrates that a BA approach can substantially enhance in situ bioremediation not only in fractures connected to the injection well, but also in the rock matrix around the well due to processes such as diffusion and desorption. Because the effect of the

  13. Reactor for biological elimination of poorly degradable hydrocarbons by adjustment of substrate-specific retention times; Reaktor zur biologischen Eliminierung schwer abbaubarer Kohlenwasserstoffe durch Einstellung substratspezifischer Verweilzeiten

    Energy Technology Data Exchange (ETDEWEB)

    Brambach, R.

    1997-11-01

    Industrial waste water cleaning increasingly makes use of biological processes based on immobilized biomass, in order to ensure the aimed elimination of toxic substances. A novel, efficient reactor technique was developed, by which dangerous, poorly degradable dissolved hydrocarbons are selectively retained in the bioreactor thanks to an integrated membrane, while other substances are quickly discharged from the system via the effluent. With a synthetic waste water, this selective retention method achieved substrate-specific retention times which were five to fifty times higher than those of a merely hydrodynamically operated reactor system. In addition, the decoupling of high reactor and low effluent concentrations results in a higher biochemical activity in the reactor in comparison with conventional process techniques. (orig.) [Deutsch] In der industriellen Abwasserreinigung werden verstaerkt Bioverfahrenstechniken mit immobilisierter Biomasse eingesetzt, um eine gezielte Eliminierung gefaehrlicher Stoffe durchzufuehren. - Hierzu wurde eine neuartige leistungsfaehige Reaktortechnik entwickelt, die mittels einer im Bioreaktor integrierten Membran gefaehrliche, schwer abbaubare geloeste Kohlenwasserstoffe selektiv im Bioreaktor zurueckhaelt, waehrend andere Stoffe das System schnell ueber den Ablauf verlassen. Durch den stoffselektiven Rueckhalt wurden an einem synthetischen Abwasser substratspezifische Verweilzeiten erzielt, die um den Faktor 5 bis 50 ueber denen eines rein hydrodynamisch bestimmten Reaktorsystems liegen. Darueber hinaus wird aufgrund der Entkopplung von hoher Reaktor- und niedriger Ablaufkonzentration eine im Vergleich zu herkoemmlichen Verfahrenstechniken hoehere biochemische Aktivitaet im Reaktor erzielt. (orig.)

  14. Degradation of Polycyclic Aromatic Hydrocarbons during Composting of Sewage Sludge%污泥堆腐过程中多环芳烃(PAHs)的降解

    Institute of Scientific and Technical Information of China (English)

    梁晶; 彭喜玲; 方海兰; 南蓬

    2011-01-01

    In the light of utilization of organic waste resource, a composting process of mixture of sewage sludge and greenery waste was carried out to study the degradation of polycyclic aromatic hydrocarbons (PAHs), which would provide clear evidence for the practice. Results indicated that total content of 16 priority PAHs in the maturation phase decreased to 3.202 mg/kg from the original 6.225 mg/kg, with degradation rate about 48.57%, and final PAHs content satisfied the accepted European Union cut-off limits for sludge to be considered safe for agricultural application set at 6 mg/kg. As far as an individual PAHs was concerned, PAHs containing fewer aromatic rings were easier to be degraded, which might be because the tendency of bioavailability of various PAH compounds during composting is strongly related to number of aromatic rings, molecular weight and sancture.%结合有机废弃物资源化利用的特点,进行了污泥与绿化植物废弃物堆肥实验,以探讨其中多环芳烃的降解状况,为其更好的资源化利用提供坚实的证据.研究表明,污泥与绿化植物废弃物物堆肥腐熟时,16种优控多环芳烃的总量由原来的6.225 mg/kg降到了3.202mg/kg,降解率达到了48.57%,并且堆肥后满足了欧洲联盟规定的多环芳烃农用限值6mg/kg.就单个多环芳烃化合物而言,环数越少降解效果越好,分析其原因可能与PAHs所含苯环多少以及其分子量大小有关.

  15. Development of an analysis method for determining chlorinated hydrocarbons in marine sediments and suspended matter giving particular consideration to supercritical fluid extraction; Entwicklung eines Analysenverfahrens zur Bestimmung von chlorierten Kohlenwasserstoffen in marinen Sedimenten und Schwebstoffen unter besonderer Beruecksichtigung der ueberkritischen Fluidextraktion

    Energy Technology Data Exchange (ETDEWEB)

    Sterzenbach, D.

    1997-11-01

    The purpose of the present study was to develop an analysis method for chlorinate hydrocarbons in marine environments using supercritical fluid extraction (SFE) instead of conventional approaches. In order to apply this extraction method the available SFE device had to be extended and all the individual steps of the analysis method had to be optimised and adapted. As chlorinated hydrocarbons only occur at very low concentrations in marine environments (ppm to ppt range) the analysis method had to be extremely sensitive. High sensitivity, in town, is generally associated with a high susceptibility of an analysis method to faults through contamination or losses. This meant that the entire method and all its individual steps had to scrutinised for such weak points and improved where necessary. A method for sampling suspended matter in marine environments had to be developed which permits efficient separation of the smallest possible particles from seawater. The designated purpose of the developed analysis method is to deal with topical aspects of marine chemistry relating to sources, transport, distribution, and the fate of chlorinated hydrocarbons in marine environments. (orig.) [Deutsch] Ziel der vorliegenden Arbeit ist, ein Analysenverfahren fuer chlorierte Kohlenwasserstoffe in der marinen Umwelt zu entwickeln. Dabei soll die ueberkritische Fluidextraktion (SFE) anstelle herkoemmlicher Verfahren eingesetzt werden. Fuer die Anwendung dieser Extraktionsmethode ist es erforderlich, das zur Verfuegung stehende SFE-Geraet zu erweitern und saemtliche Teilschritte des Analysenverfahrens zu optimieren und auf diese Methode abzustimmen. Der Umstand, dass die chlorierten Kohlenwasserstoffe nur in sehr geringen Konzentrationen in der marinen Umwelt vorkommen (ppm- bis ppt-Bereich), erfordert eine sehr hohe Empfindlichkeit des Analysenverfahrens. Eine hohe Empfindlichkeit bedingt eine grosse Stoeranfaelligkeit des Analysenverfahrens durch Kontaminationen oder Verluste. Aus

  16. ANAEROBIC AND AEROBIC TREATMENT OF CHLORINATED ALIPHATIC COMPOUNDS

    Science.gov (United States)

    Biological degradation of 12 chlorinated aliphatic compounds (CACs) was assessed in bench-top reactors and in serum bottle tests. Three continuously mixed daily batch-fed reactor systems were evaluated: anaerobic, aerobic, and sequential-anaerobic-aerobic (sequential). Glucose,...

  17. Technology assessment: Chlorine chemistry

    International Nuclear Information System (INIS)

    Chlorine is not just one of many chemical feedstocks which is used in a few definitely harmful products like PVC or CFC but is irrelevant in all other respects. Just the opposite is true: There is hardly any product line of the chemical industry that can do without chlorine, from herbicides and pesticides to dyes, plastics, pharmaceuticals, photographic atricles, and cosmetics. Chlorine is not only a key element of chemical production but also an ubiquitous element of everyday life in civilisation. There are even many who would agree that the volume of chlorine production is an indicator of the competitive strength and national wealth of a modern society. By now, however, it has become evident that the unreflected use of chlorine is no longer ecologically acceptable. The consequences of a chlorine phase-out as compared to the continued chlorine production at the present level were investigated scientifically by a PROGNOS team. They are presented in this book. (orig.)

  18. Challenges in subsurface in situ remediation of chlorinated solvents

    OpenAIRE

    Broholm, Mette Martina; Fjordbøge, Annika Sidelmann; Christiansen, Camilla Maymann; Hønning, J.; B. H. Hansen; Nedergaard, L. W.; Kern, Kristina; Uthuppu, Basil; Jakobsen, Mogens Havsteen; Kjeldsen, Peter; Bjerg, Poul Løgstrup; Ottesen, L.

    2014-01-01

    Chlorinated solvent source zones in the subsurface pose a continuous threat to groundwater quality at many sites worldwide. In situ remediation of these sites is particularly challenging in heterogeneous fractured media and where the solvents are present as DNAPL. In situ remediation by chemical as well as biological degradation of chlorinated solvents is a contact sport and requires direct contact between the contaminant and the reactants and/or degrading microorganisms. In fractured geologi...

  19. Croceicoccus naphthovorans sp. nov., a polycyclic aromatic hydrocarbons-degrading and acylhomoserine-lactone-producing bacterium isolated from marine biofilm, and emended description of the genus Croceicoccus.

    Science.gov (United States)

    Huang, Yili; Zeng, Yanhua; Feng, Hao; Wu, Yuehong; Xu, Xuewei

    2015-05-01

    A polycyclic aromatic hydrocarbons-degrading and acylhomoserine-lactone-producing marine bacterium, designated strain PQ-2(T), was isolated from marine biofilm collected from a boat shell at a harbour of Zhoushan island in Zhejiang Province, PR China. Strain PQ-2(T) is Gram-stain-negative, yellow-pigmented, non-motile and short rod-shaped. Optimal growth of strain PQ-2(T) was observed at 32 °C, at pH 7.0 and in 2% (w/v) NaCl. The 16S rRNA gene sequence of strain PQ-2(T) showed highest similarity to Croceicoccus marinus E4A9(T) (96.3%) followed by Novosphingobium malaysiense MUSC 273(T) (95.6%) and Altererythrobacter marinus H32(T) (95.6%). Phylogenetic analysis with all species of the family Erythrobacteraceae with validly published names revealed that strain PQ-2(T) formed a phyletic line with Croceicoccus marinus E4A9(T) that was distinct from other members of the family Erythrobacteraceae . The sole respiratory quinone was ubiquinone 10 (Q-10). The predominant fatty acids were C18 : 1ω7c, C17 : 1ω6c and summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH). The genomic DNA G+C content was 61.7 mol%. In the polar lipid profile, phosphatidylethanolamine, phosphatidylcholine, phosphatidylglycerol, one unidentified phospholipid and one sphingoglycolipid were the major compounds; and another sphingoglycolipid was present in a minor amount. Based on the genotypic and phenotypic data, strain PQ-2(T) represents a novel species of the genus Croceicoccus , for which the name Croceicoccus naphthovorans sp. nov. is proposed. The type strain is PQ-2(T) ( =CGMCC 1.12805(T) =NBRC 110381(T)). In addition, emended descriptions for the genus Croceicoccus and the species C. marinus are given. PMID:25713040

  20. Biochemical ripening of dredged sediments. Part 2. Degradation of polycyclic aromatic hydrocarbons and total petroleum hydorcarbons in slurried and consolidated sediments

    NARCIS (Netherlands)

    Vermeulen, J.; Gool, van M.P.M.; Mentink, G.H.; Joziasse, J.; Bruning, H.; Grotenhuis, J.T.C.

    2007-01-01

    Ripening of polycyclic aromatic hydrocarbons (PAH) and total petroleum hydrocarbons (TPH) polluted dredged sediment can be considered as a bioremediation technique. Aerobic biodegradation of PAH and TPH was studied in five previously anaerobic-slurried sediments during a 350-d laboratory incubation

  1. Biodegradation of petroleum hydrocarbons in hypersaline environments

    Directory of Open Access Journals (Sweden)

    Luiz Fernando Martins

    2012-09-01

    Full Text Available Literature on hydrocarbon degradation in extreme hypersaline media presents studies that point to a negative effect of salinity increase on hydrocarbonoclastic activity, while several others report an opposite tendency. Based on information available in the literature, we present a discussion on the reasons that justify these contrary results. Despite the fact that microbial ability to metabolize hydrocarbons is found in extreme hypersaline media, indeed some factors are critical for the occurrence of hydrocarbon degradation in such environments. How these factors affect hydrocarbon degradation and their implications for the assessment of hydrocarbon biodegradation in hypersaline environments are presented in this review.

  2. Degradation of chlorobenzoates and chlorophenols by methanogenic consortia

    NARCIS (Netherlands)

    Ennik-Maarsen, K.

    1999-01-01

    Pollution of the environment with chlorinated organic compounds mainly results from (agro)industrial activity. In many studies, biodegradation is examined under anaerobic conditions, because highly chlorinated compounds are more easily degradable under anaerobic than under aerobic conditions. Proble

  3. Review of reactive kinetic models describing reductive dechlorination of chlorinated ethenes in soil and groundwater

    DEFF Research Database (Denmark)

    Chambon, Julie Claire Claudia; Bjerg, Poul Løgstrup; Scheutz, Charlotte;

    2013-01-01

    Reductive dechlorination is a major degradation pathway of chlorinated ethenes in anaerobic subsurface environments, and reactive kinetic models describing the degradation process are needed in fate and transport models of these contaminants. However, reductive dechlorination is a complex biologi...

  4. Anaerobic degradation of aromatic hydrocarbons

    International Nuclear Information System (INIS)

    This paper reports that toluene and m-xylene were rapidly mineralized in a denitrifying laboratory aquifer column operated under continuous flow conditions in the complete absence of molecular oxygen. A bacterium, tentatively identified as a Pseudomonas sp., was isolated from this column. This organism mineralized toluene and m-xylene under pure culture conditions with nitrate or nitrous oxide as the sole electron acceptors. Carbon balance studies using 0.3mM [ring-UL-14C]toluene revealed that more than 50 percent of the radioactivity was evolved as 14CO2

  5. Chlorinated organic compounds produced by Fusarium graminearum.

    Science.gov (United States)

    Ntushelo, Khayalethu

    2016-06-01

    Fusarium graminearum, a pathogen of wheat and maize, not only reduces grain yield and degrades quality but also produces mycotoxins in the infected grain. Focus has been on mycotoxins because of the human and animal health hazards associated with them. In addition to work done on mycotoxins, chemical profiling of F. graminearum to identify other compounds produced by this fungus remains critical. With chemical profiling of F. graminearum the entire chemistry of this fungus can be understood. The focus of this work was to identify chlorinated compounds produced by F. graminearum. Various chlorinated compounds were detected and their role in F. graminearum is yet to be understood. PMID:27165533

  6. 酸碱气体对氯代芳烃削减的影响%Influence of acid and basic gases on the reduction of chlorinated aromatics

    Institute of Scientific and Technical Information of China (English)

    刘莎; 黄学敏; 黄林艳; 孙丽芳; 黎烈武; 刘烨煊; 苏贵金

    2014-01-01

    氯代芳烃多属于一种高毒性、难降解的持久性有机污染物,对环境和人类健康具有极大的危害。因此,削减其在环境的排放至关重要。在垃圾焚烧、化石燃料燃烧、铁矿石烧结等工业过程中,除存在氯代芳烃污染物外,还常伴有酸性气体二氧化硫、氮氧化物、氯化氢和碱性气体氨气的存在。这些气体物质的共存对氯代芳烃的削减具有重要的影响。本文综述了二氧化硫、氮氧化物、氯化氢和氨气等气体物质对氯代芳烃污染物在热催化过程和光降解过程中的降解、生成及阻滞的影响作用,阐述了其影响氯代芳烃削减和生成的机理,然后对研究过程中获得的成果和存在的问题进行了总结,并对气体污染物和氯代芳烃协同去除技术的研究方向进行了展望。%Chlorinated aromatic hydrocarbons, as a group of toxic, difficult to degrade and persistent organic pollutant, had significantly negative impacts on environment and human health. Therefore, it is vital to minimize their release in to the environment. During some industrial processes, such as, waste incineration, fossil fuel combustion and iron ore sintering, there exist acid gases such as sulfur dioxide, nitrogen oxides, hydrogen chloride, and also basic gases, such as ammonia, in addition to the unitentional release of chlorinated aromatic hydrocarbons. These coexisting gaseous substances could be expected to have significant impact on the release of chlorinated aromatics. This paper reviews the influence of sulfur dioxide, nitrogen oxides, hydrogen chloride and ammonia on the degradation, production, and inhibition of chlorinated aromatics in thermal catalytic and photodegradation processes, and disscussed mechanism. Further development of synergetic degradation of gas pollutants and chlorinated aromatic hydrocarbons is proposed.

  7. Water Treatment Technology - Chlorination.

    Science.gov (United States)

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on chlorination provides instructional materials for nine competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: purpose and process of chlorination, chlorine…

  8. He-Ne激光诱变选育高效石油烃降解菌的研究%Study on screening of a highly petroleum hydrocarbon-degrading bacteria by He-Ne laser induced mutation

    Institute of Scientific and Technical Information of China (English)

    张子间; 刘勇弟; 卢杰; 张立辉

    2012-01-01

    采用He-Ne激光器对绿针假单胞菌(Pseudomonas chlororaphis)进行激光诱变育种。在激光照射功率10 mW,时间10 min条件下,筛选到一株遗传性状稳定的高效石油烃降解菌PS 2。摇瓶实验发现当培养液中初始柴油含量为0.2%~0.5%(V/V)、温度为30℃左右、pH值为7~8的条件下,突变菌PS 2对石油烃的降解效果最好。在最适生长条件下,突变菌PS 2在120 h内将培养液中的石油烃完全降解且不存在延滞期,比出发菌株少用24 h。结果表明,He-Ne激光诱变育种技术是获得高效石油烃降解菌的有效途径之一。%The Pseudomonas chlororaphis was irradiated at 10 mW for 10 minutes using He-Ne laser.A mutant PS 2 with steady genetic characteristics and high degradation rate of petroleum hydrocarbon was obtained.The result showed that degradation efficiency is satisfactory when the content of petroleum hydrocarbon is 0.2%-0.5%(V/V),temperture is about 30℃,pH is 7-8 in the batch culture experiment.Under these conditions for optimum growth,petroleum hydrocarbon could be completely degraded by mutant PS 2 within 120 h without lag phase.The results showed that laser inducing was one of effective ways for screening excellent petroleum hydrocarbon-degrading strains.

  9. Chlorination of organophosphorus pesticides in natural waters.

    Science.gov (United States)

    Acero, Juan L; Benítez, F Javier; Real, Francisco J; González, Manuel

    2008-05-01

    Unknown second-order rate constants for the reactions of three organophosphorus pesticides (chlorpyrifos, chlorfenvinfos and diazinon) with chlorine were determined in the present study, and the influence of pH and temperature was established. It was found that an increase in the pH provides a negative effect on the pesticides degradation rates. Apparent second-order rate constants at 20 degrees C and pH 7 were determined to be 110.9, 0.004 and 191.6 M(-1) s(-1) for chlorpyrifos, chlorfenvinfos and diazinon, respectively. A higher reactivity of chlorine with the phosphorothioate group (chlorpyrifos and diazinon) than with the phosphate moiety (chlorfenvinfos) could explain these results. Intrinsic rate constant for the elementary reactions of chlorine species with chlorpyrifos and diazinon were also calculated, leading to the conclusion that the reaction between hypochlorous acid and the pesticide is predominant at neutral pH. The elimination of these pesticides in surface waters was also investigated. A chlorine dose of 2.5 mg L(-1) was enough to oxidize chlorpyrifos and diazinon almost completely, with a formation of trihalomethanes below the EU standard for drinking water. However, the removal of chlorfenvinfos was not appreciable. Therefore, chlorination is a feasible option for the removal of organophosphorus pesticides with phosphorothioate group during oxidation and disinfection processes, but not for the elimination of pesticides with phosphate moiety.

  10. Sonochemical Treatment of Water Polluted by Chlorinated Organocompounds. A Review

    Directory of Open Access Journals (Sweden)

    Olivier Louisnard

    2010-02-01

    Full Text Available As one of several types of pollutants in water, chlorinated compounds have been routinely subjected to sonochemical analysis to check the environmental applications of this technology. In this review, an extensive study of the influence of the initial concentration, ultrasonic intensity and frequency on the kinetics, degradation efficiency and mechanism has been analyzed. The sonochemical degradation follows a radical mechanism which yields a very wide range of chlorinated compounds in very low concentrations. Special attention has been paid to the mass balance comparing the results from several analytical techniques. As a conclusion, sonochemical degradation alone is not an efficient treatment to reduce the organic pollutant level in waste water.

  11. Reaction products of chlorine dioxide.

    OpenAIRE

    Stevens, A A

    1982-01-01

    Inspection of the available literature reveals that a detailed investigation of the aqueous organic chemistry of chlorine dioxide and systematic identification of products formed during water disinfection has not been considered. This must be done before an informed assessment can be made of the relative safety of using chlorine dioxide as a disinfectant alternative to chlorine. Although trihalomethanes are generally not formed by the action of chlorine dioxide, the products of chlorine dioxi...

  12. RESEARCH ON MATHEMATICAL SIMULATION OF RESIDUAL CHLORINE DECAY AND OPTIMIZATION OF CHLORINATION ALLOCATION OF URBAN WATER DISTRIBUTION SYSTEM

    Institute of Scientific and Technical Information of China (English)

    TIAN Yi-mei; CHI Hai-yan; LI Hong; SHAN Jin-lin; ZHAI Chun-nian

    2005-01-01

    The concentration of Residual Chlorine (RC) frequently violates the standard in situations of urban water distribution system with large water supply area and long time of distribution.If chlorine dosage increases within water treatment plant, although RC in distribution system could meet water quality standard, Disinfection By-Products (DBPs) such as hydrocarbon halide rises.In the paper, a mathematical model of chlorine allocation optimization was presented based on reaction kinetics mechanism and optimization theory to solve the problem.The model includes the objective function of minimizing annual operation cost and constraints of RC standard and rational chlorination station distribution, and solving by 0-1 Integer Programming (IP).The model had been applied to a real water distribution system.The simulation results of the model showed that adding chlorine in water distribution system remarkably improved water quality and reduced the operation cost by 49.3% per year less than chlorine dosed only in water treatment plant to meet RC standard.The results prove adding chlorine in water distribution system based on the model can bring both technological and economic advancement.

  13. Zirconia concentrate chlorination

    International Nuclear Information System (INIS)

    Chlorination experiments were conducted in order to study the kinetics of gasification of the zirconium oxide present in the zirconia concentrate. The variables studied are temperature (1173 to 1373 K), percentage of reducing agent (12 to 36%) and porosity (22 to 30%). The results indicated a greater influence of temperature and percentage of reducing agent as well as allowed the conclusion that a balance between the levels of these variables is an important factor in the appropriate chlorination conditions. (author)

  14. Degradation of terbutylazine (2-chloro-4-ethylamino-6-terbutylamino-1,3,5-triazine), deisopropyl atrazine (2-amino-4-chloro-6-ethylamino-1,3,5-triazine), and chlorinated dimethoxy triazine (2-chloro-4,6-dimethoxy-1,3,5-triazine) by zero valent iron and electrochemical reduction

    International Nuclear Information System (INIS)

    To help elucidate the mechanism of dechlorination of chlorinated triazines via metallic iron, terbutylazine (TBA: 2-chloro-4-ethylamino-6-terbutylamino-1,3,5-triazine), deisopropyl atrazine (DIA: 2-amino-4-chloro-6-ethylamino-1,3,5-triazine), and chlorinated dimethoxy triazine (CDMT: 2-chloro-4,6-dimethoxy-1,3,5-triazine) were degraded via zero valent iron under controlled pH conditions. The lower the solution pH the faster the degradation, with surface area normalized pseudo first order rate constants ranging from 2 (±1)x10-3 min-1 m-2 l for TBA at pH 2.0 to 4 (±2)x10-5 min-1 m-2 l for CDMT at pH 4.0. Hydrogenolysis (dechlorinated) products were observed for TBA and CDMT. Electrochemical reduction on mercury showed similar behavior for all of the triazines studied; the initial product of CDMT bulk electrolysis was the dechlorinated compound. The iron results are consistent with a mechanism involving the addition of surface hydrogen to the surface associated triazine. - Reductive dechlorination via zero valent iron is dependent upon solution pH and the specific triazine

  15. Breakpoint chlorination curves of greywater.

    Science.gov (United States)

    March, J G; Gual, M

    2007-08-01

    A study on chlorination of raw greywater with hypochlorite is reported in this paper. Samples were chlorinated in a variety of conditions, and residual chlorine (Cl2) was measured spectrophotometrically. For each sample, the chlorination curve (chlorine residuals versus chlorine dose) was obtained. Curves showed the typical hump-and-dip profile attributable to the formation and destruction of chloramines. It was observed that, after reactions with strong reductants and chloramines-forming compounds, the remaining organic matter exerted a certain demand of chlorine. The evolution of chlorination curves with addition of ammonia and dodecylbencene sulfonate sodium salt and with dilution of the greywater sample were studied. In addition, chlorination curves at several contact times have been obtained, resulting in slower chlorine decay in the hump zone than in the dip zone. In addition, the decay of coliforms in chlorinated samples was also investigated. It was found that, for a chlorination dosage corresponding to the maximum of the hump zone (average 8.9 mg Cl2/ L), samples were negative in coliforms after 10 to 30 minutes of contact time. After-growth was not observed within 3 days after chlorination. Implications in chlorination treatments of raw greywater can be derived from these results. PMID:17824528

  16. INVESTIGATION OF THE NUTRITIONAL REQUIREMENTS AND CORRESPONDING CODING GENES OF HYDROCARBON-DEGRADING BACTERIAL STRAINS FOR THE PRODUCTION OF BIOMASS USEFUL IN BIOREMEDIATION OF PETROLEUM POLLUTION

    OpenAIRE

    Attar, Al Zahraa Omar

    2015-01-01

    Petroleum-derived contamination events constitute one of the most dominant sources of environmental deterioration in the industrialized countries. Hydrocarbon compounds are recognized as toxic and carcinogenic organic pollutants and environmentally persistent. Bioremediation efforts aim to confine, restrain and mitigate the magnitude of contamination, in order to prevent additional decline of the environment and to protect all life forms from exposure to hazardous materials. The aim of this p...

  17. Application of thermal desorption to the development of a gas chromatographic/mass spectrometric method for the determination of toluene, chlorinated aromatic hydrocarbons, and 2,3,7,8-tetrachlorodibenzo-p-dioxin in combustion emissions.

    Science.gov (United States)

    Donaldson, John D; Grimes, Susan M; Mehta, Lina; Jafari, Ahmad J

    2003-01-01

    A fast and accurate analytical method, which uses commercially available adsorbents (Tenax TA, Carbotrap B and C, and Carbosieve S-III), was developed for the sampling and determination of aromatic hydrocarbons, chloroaromatic compounds, and 2,3,7,8-tetrachlorodibenzo-p-dioxin. The breakthrough volume data show that Carbotrap C has a good capacity for compounds of high molecular weight, whereas Carbosieve S-III and Tenax TA are efficient for volatile compounds. The organic components are thermally desorbed and transferred to a gas chromatograph/mass spectrometer. Importantly, thermal desorption avoids conventional solvent extraction procedures and also allows reuse of adsorbent tubes. Preliminary results for recovery of analytes from tubes packed with single adsorbent prove that a single-adsorbent bed is not capable of sampling a wide range of compounds. The best method to obtain the desired collection and desorption properties is to use adsorbent tubes containing several different materials. The results of optimization studies are summarized. PMID:12607738

  18. Synergistic prevention of biofouling in seawater desalination by zwitterionic surfaces and low-level chlorination.

    Science.gov (United States)

    Yang, Rong; Jang, Hongchul; Stocker, Roman; Gleason, Karen K

    2014-03-19

    Smooth, durable, ultrathin antifouling layers are deposited onto commercial reverse osmosis membranes without damaging them and they exhibit a fouling reduction. A new synergistic approach to antifouling, by coupling surface modification and drinking-water-level chlorination is enabled by the films' unique resistance against chlorine degradation. This approach substantially enhances longer-term fouling resistance compared with surface modification or chlorination alone, and can reduce freshwater production cost and its collateral toxicity to marine biota.

  19. Chlorine, Chloramine, Chlorine Dioxide, and Ozone Susceptibility of Mycobacterium avium

    OpenAIRE

    Taylor, Robert H.; Joseph O. Falkinham; Norton, Cheryl D.; LeChevallier, Mark W.

    2000-01-01

    Environmental and patient isolates of Mycobacterium avium were resistant to chlorine, monochloramine, chlorine dioxide, and ozone. For chlorine, the product of the disinfectant concentration (in parts per million) and the time (in minutes) to 99.9% inactivation for five M. avium strains ranged from 51 to 204. Chlorine susceptibility of cells was the same in washed cultures containing aggregates and in reduced aggregate fractions lacking aggregates. Cells of the more slowly growing strains wer...

  20. Spatial and temporal variability of inorganic chlorine in Northwestern Europe

    Science.gov (United States)

    Sommariva, R.; Hollis, L. D. J.; Baker, A. R.; Ball, S. M.; Bell, T. G.; Cordell, R. L.; Fleming, Z.; Gaget, M.; Yang, M. X.; Monks, P. S.

    2015-12-01

    Chlorine is well known to be a strong oxidant in the atmosphere;chlorine reactivity impacts the formation of tropospheric ozone, theoxidation of methane and non-methane hydrocarbons, and the cycling ofnitrogen, sulphur and mercury. An accurate assessment of the roleplayed by chlorine in tropospheric chemical processes is complicatedby the scarce knowledge of its sources, sinks and distribution.We report observations of inorganic chlorine species (Cl2, ClNO2,particulate chloride) taken over the period 2014-2015 at threedifferent locations in Britain: an urban site a hundred kilometersfrom the ocean (Leicester), a coastal site mostly affected by shiptraffic (Penlee Point, Cornwall) and a coastal site experiencingeither clean air from the North Sea or polluted air from inland(Weybourne, Norfolk).This dataset provides a first look into the geographical distributionand seasonal variability of chlorine in Northwestern Europe: theresults suggest that, during the night, ClNO2 is ubiquitous withconcentrations in the range of hundreds to thousands of pptV at alllocations, whereas Cl2 can be observed only at coastal sites, withconcentrations of a few tens of pptV. The implications of thewidespread presence of these forms of inorganic chlorine for ozoneproduction and, in general, for the oxidative processes in the loweratmosphere are discussed with the help of a wide range of supportingmeasurements.

  1. Chlorine dioxide as phenol and H2S scavenger - formation of halogenated phenols and subsequent environmental risk

    Energy Technology Data Exchange (ETDEWEB)

    Melbye, Alf G.; Faksness, Liv-Guri; Knudsen, Boerre Leif

    2006-03-15

    Formation of halogenated phenols as side products from treatment of produced water with aqueous chlorine dioxide has been investigated. The literature describes formation of halogenated hydrocarbons in effluent treatment using chlorine, hypochlorite and chlorine dioxide. A new chlorine dioxide product, originally intended as a H2S scavenger in the oil and gas industry, has been tested both as a phenol scavenger and H2S-scavenger for produced water applications. The concern about the possible formation of halogenated by-products initiated laboratory testing of chlorine dioxide as phenol and H2S scavenger for produced water applications. The tests also included synthetic matrixes containing phenols, and the tests show that halogenated phenols, mainly brominated species, are found in produced water after treatment with chlorine dioxide. Due to potential environmental risk from halogenated organic contaminants, the use of chlorine dioxide as phenol and H2S scavenger is not recommended. (Author)

  2. Snapping Turtles (Chelydra serpentina) from Canadian Areas of Concern across the southern Laurentian Great Lakes: Chlorinated and brominated hydrocarbon contaminants and metabolites in relation to circulating concentrations of thyroxine and vitamin A.

    Science.gov (United States)

    Letcher, Robert J; Lu, Zhe; de Solla, Shane R; Sandau, Courtney D; Fernie, Kimberly J

    2015-11-01

    The metabolites of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), as well as other halogenated phenolic contaminants (HPCs) have been shown to have endocrine-disrupting properties, and have been reported with increasing frequency in the blood of wildlife, and mainly in mammals and birds. However, little is known about the persistence, accumulation and distribution of these contaminants in long-lived freshwater reptiles. In the present study, in addition to a large suite of chlorinated and brominated contaminants, metabolites and HPCs, we assessed and compared hydroxylated (OH) PCBs and OH-PBDEs relative to PCBs and PBDEs, respectively, in the plasma of adult male common snapping turtles (Chelydra serpentina). Blood samples were collected from 62 snapping turtles (2001-2004) at 12 wetland sites between the Detroit River and the St. Lawrence River on the Canadian side of the Laurentian Great Lakes of North America. Turtles were sampled from sites designated as Areas of Concern (AOCs) and from a relatively clean reference site in southern Georgian Bay (Tiny Marsh), Lake Huron. Plasma concentrations of Σ46PCB (10-340 ng/g wet weight (ww)) and Σ28OH-PCB (3-83 ng/g ww) were significantly greater (pLake Erie compared with the reference site turtles. The HPC, pentachlorophenol (PCP), had a mean concentration of 9.6±1.1 ng/g ww. Of the 28 OH-CB congeners screened for, 4-OH-CB187 (42±7 ng/g ww) was the most concentrated of all HPCs measured. Of the 14 OH-BDE congeners examined, four (4'-OH-BDE17, 3-OH-BDE47, 5-OH-BDE47 and 4'-OH-BDE49) were consistently found in all plasma samples. p,p'-DDE was the most concentrated of the 18 organochlorine pesticides (OCPs) examined. The mean concentrations of circulating total thyroxine (TT4), dehydroretinol and retinol in the plasma of the male snapping turtles regardless of sampling site were 5.4±0.3, 81±4.7 and 291±13 ng/mL, respectively. Significant (pLake Erie and Lake Ontario (in 2001-2004) had

  3. Lipid enrichment of Chlorella sp.and Dunaliella salina by degradation of petroleum hydrocarbons%小球藻和盐藻利用石油烃富集油脂的研究

    Institute of Scientific and Technical Information of China (English)

    梁译之; 范禹辰; 高杨; 宁淑香; 李铁松

    2013-01-01

    利用单细胞分离和紫外诱变技术分别获得海水小球藻和盐生杜氏藻的生长优势株,将其分别接种于不同石油浓度的海水培养液中,利用紫外和荧光分光光度法分别测定培养液中带共轭双键的烃类化合物和芳烃的含量,利用索氏提取法测定胞内油脂含量.结果表明,石油浓度为1.5~10.0μg/ml的培养液中,小球藻和盐藻均能有效降解带共轭双键的烃类化合物,降解率分别为25.3%~35.5%和17.9%~24.0%,芳烃降解率分别为22.1%~30.2%和18.7%~26.2%;石油浓度为3.5μg/ml时,两种微藻对带共轭双键的烃类化合物和芳烃的降解效率均最大,小球藻的降解能力略好于盐藻;石油浓度为1.5μg/ml和3.5μg/ml时,两种微藻的胞内油脂含量分别占细胞干重的14.0%和25.5%,分别是对照组的1.5倍和1.2倍,浓度为3.5μg/ml时两种微藻的胞内油脂含量均最高.该研究为利用石油污染海水培养微藻使其富集油脂及今后开发微藻燃料奠定了基础.%This study aims to investigate the possibility of using marine microalgae (green microalgae) to degrade petroleum hydrocarbons and converse them into lipids in cells.Rapid growth strains of Chlorella sp.and Dunaliella salina were obtained by single separation technology and ultraviolet mutation breeding techniques.The mutagenesis dominant strains were then cultured in oily seawater with different oil concentrations.The contents of conjugated hydrocarbon compounds and petroleum aromatic hydrocarbons were determined respectively by UV spectrophotometry and fluorescence spectrophotometry.The lipid content of the microalgae cells was measured by the Soxhlet extraction method.The results showed that Chlorella and D.salina were able to degrade petroleum hydrocarbons effectively at oil concentrations of 1.5~10.0μg/ml.The degradation rates of conjugated hydrocarbon compounds were 25.3 % ~39.5 %and 17.9 % ~24.0

  4. Biodegradation of chlorinated ethenes by a methane-utilizing mixed culture

    International Nuclear Information System (INIS)

    Chlorinated ethenes are toxic substances which are widely distributed groundwater contaminants and are persistent in the subsurface environment. Reports on the biodegradation of these compounds under anaerobic conditions which might occur naturally in groundwater show that these substances degrade very slowly, if at all. Previous attempts to degrade chlorinated ethenes aerobically have produced conflicting results. A mixed culture containing methane-utilizing bacteria was obtained by methane enrichment of a sediment sample. Biodegradation experiments carried out in sealed culture bottles with radioactively labeled trichloroethylene (TCE) showed that approximately half of the radioactive carbon had been converted to 14CO2 and bacterial biomass. In addition to TCE, vinyl chloride and vinylidene chloride could be degraded to products which are not volatile chlorinated substances and are therefore likely to be further degraded to CO2. Two other chlorinated ethenes, cis and trans-1,2-dichloroethylene, were shown to degrade to chlorinated products, which appeared to degrade further. A sixth chlorinated ethene, tetrachloroethylene, was not degraded by the methane-utilizing culture under these conditions. The biodegradation of TCE was inhibited by acetylene, a specific inhibitor of methane oxidation by methanotrophs. This observation supported the hypothesis that a methanotroph is responsible for the observed biodegradations

  5. 计算机重构石油烃降解的微生物代谢途径%Computational Reconstruction of Microbial Pathways for Degradation of Petroleum Hydrocarbons

    Institute of Scientific and Technical Information of China (English)

    王东; 何涛; 邵卫东; 汪莉; 王玉民

    2012-01-01

    目的:用计算机重构石油烃降解通路,为石油污染的生物修复提供理论依据.方法:利用KEGG反应、化合物数据提取反应等式,过滤掉所有反应中的通用化合物及小分子化合物并构建反应矩阵,然后利用广度优先搜索算法在反应矩阵中搜索降解石油烃的代谢途径.结果:计算机分别重构了256 132条链烷烃降解途径和44条环己烷降解途径,以酿酒酵母作为降解石油烃的基因工程菌为例,通过限制改构菌整合的关键酶数目,分别得到了213条不需要转入关键酶的链烷烃降解通路和6条以氧化还原酶、松柏醇脱氢酶或环己醇脱氢酶和环己酮单氧酶为关键酶的环己烷降解通路,并构建相应的降解网络图,标注每个反应的酶.结论:应用计算机重构了2种石油烃降解途径,可为利用微生物对石油污染进行生物修复提供理论依据.%Objective: Metabolic pathways for degradation of petroleum hydrocarbons were reconstructed by computational skills to provide theoretical basis for the bioremediation of oil polution. Methods: At first, the reaction equations were extracted from the KEGC reaction database and the compound database. And then current metabolites and micromolecule compounds in all the reactions were filtered out. Finally, the reaction matrix was constructed to search metabolic pathways for degrading petroleum hydrocarbons by the breadth first search approach. Results: 256 132 pathways for degrading alkanes and 44 pathways for degrading cyclohexane were reconstructed by computational skills. Taking Saccharomyces cerevisiae as the genetic engineering bacteria, we picked out 219 pathways by limiting the number of pivotal enzymes to construct the metabolic network, including 213 pathways without key enzymes and 6 pathways with oxidoreductases, coniferyl alcohol dehydrogenase or cyclohexanol dehydroge-nase and cyclohexanone monooxygenase as key enzymes. Catalytic enzymes of every reaction

  6. Detection and characterization of chlorinated-dioxin ether cleavage function in the bacterium geobacillus midousuji SH2B-J2

    Energy Technology Data Exchange (ETDEWEB)

    Otsuka, Y.; Hoshina, S. [Jikei Univ. School of Medicine, Tokyo (Japan). Dept. of Laboratory Medicine; Nakamura, M.; Hishiyama, S. [Forestry and Forest Products Research Institute, Ibaraki (Japan); Katayama, Y. [Tokyo Univ. of Agriculture and Technology, Koganei (Japan)

    2004-09-15

    As of now, there are no dioxin degrading microorganism reported that can be applied to bioremediation. The reasons for this are that degrading function acquired from comprehensive screening of bacteria that can be grown with a single carbon source using non-chlorinated dioxin does not function against highly chlorinated dioxins, and that although white rot fungus capable of degrading lignin, a plant polyphenol substance, have been reported to reduce chlorinated dioxins, degrading enzyme remain unclear. Geobacillus midousuji SH2B-J2 (J2 strain) that have been separated by Hoshina et al. have shown to reduce highly chlorinated dioxins in incineration fly ash, as well as octa-chlorinated dioxins (OCDD). However, details of its degrading mechanisms remain unclear. Since the J2 strain is capable of reducing even OCDD, it was hypothesized that the initial degradation reaction is intramolecular ether bond cleavage, so J2 strain dioxin degradation mechanism was analyzed for verification.

  7. Behavior and stability of adenosine triphosphate (ATP) during chlorine disinfection.

    Science.gov (United States)

    Nescerecka, Alina; Juhna, Talis; Hammes, Frederik

    2016-09-15

    Adenosine triphosphate (ATP) analysis is a cultivation-independent alternative method for the determination of bacterial viability in both chlorinated and non-chlorinated water. Here we investigated the behavior and stability of ATP during chlorination in detail. Different sodium hypochlorite doses (0-22.4 mg-Cl2 L(-1); 5 min exposure) were applied to an Escherichia coli pure culture suspended in filtered river water. We observed decreasing intracellular ATP with increasing chlorine concentrations, but extracellular ATP concentrations only increased when the chlorine dose exceeded 0.35 mg L(-1). The release of ATP from chlorine-damaged bacteria coincided with severe membrane damage detected with flow cytometry (FCM). The stability of extracellular ATP was subsequently studied in different water matrixes, and we found that extracellular ATP was stable in sterile deionized water and also in chlorinated water until extremely high chlorine doses (≤11.2 mg-Cl2 L(-1); 5 min exposure). In contrast, ATP decreased relatively slowly (k = 0.145 h(-1)) in 0.1 μm filtered river water, presumably due to degradation by either extracellular enzymes or the fraction of bacteria that were able to pass through the filter. Extracellular ATP decreased considerably faster (k = 0.368 h(-1)) during batch growth of a river water bacterial community. A series of growth potential tests showed that extracellular ATP molecules were utilized as a phosphorus source during bacteria proliferation. From the combined data we conclude that ATP released from bacteria at high chlorine doses could promote bacteria regrowth, contributing to biological instability in drinking water distribution systems. PMID:27295623

  8. Behavior and stability of adenosine triphosphate (ATP) during chlorine disinfection.

    Science.gov (United States)

    Nescerecka, Alina; Juhna, Talis; Hammes, Frederik

    2016-09-15

    Adenosine triphosphate (ATP) analysis is a cultivation-independent alternative method for the determination of bacterial viability in both chlorinated and non-chlorinated water. Here we investigated the behavior and stability of ATP during chlorination in detail. Different sodium hypochlorite doses (0-22.4 mg-Cl2 L(-1); 5 min exposure) were applied to an Escherichia coli pure culture suspended in filtered river water. We observed decreasing intracellular ATP with increasing chlorine concentrations, but extracellular ATP concentrations only increased when the chlorine dose exceeded 0.35 mg L(-1). The release of ATP from chlorine-damaged bacteria coincided with severe membrane damage detected with flow cytometry (FCM). The stability of extracellular ATP was subsequently studied in different water matrixes, and we found that extracellular ATP was stable in sterile deionized water and also in chlorinated water until extremely high chlorine doses (≤11.2 mg-Cl2 L(-1); 5 min exposure). In contrast, ATP decreased relatively slowly (k = 0.145 h(-1)) in 0.1 μm filtered river water, presumably due to degradation by either extracellular enzymes or the fraction of bacteria that were able to pass through the filter. Extracellular ATP decreased considerably faster (k = 0.368 h(-1)) during batch growth of a river water bacterial community. A series of growth potential tests showed that extracellular ATP molecules were utilized as a phosphorus source during bacteria proliferation. From the combined data we conclude that ATP released from bacteria at high chlorine doses could promote bacteria regrowth, contributing to biological instability in drinking water distribution systems.

  9. Separation of Petroleum Hydrocarbon Degrading Bacteria and its Application in Oily Sludge%石油烃降解菌的分离及在含油污泥中的应用

    Institute of Scientific and Technical Information of China (English)

    姚力芬; 李丹; 陈丽华; 李广彬; 孙盼盼; 李佳酿

    2015-01-01

    文章从甘肃陇东长庆油田污染严重的土壤中分离筛选得到六株石油烃降解菌,分别命名为a1、a2、a3、a4、a5和a6,对它们进行了常规鉴定,得到a1、a2、a3均为芽孢杆菌,a4、a6均为假单胞菌,a5为不动杆菌.通过菌剂的复活、发酵得到降解石油烃复合菌,并进行了微生物修复含油污泥的小试实验.结果表明,当土壤中的石油含量为50g/kg时,加入混合菌剂的石油降解率比没有加菌剂的降解效率高,添加4%菌剂后81d的降解率为90.20%,大于对照组(只添加有机肥)的降解率31.10%,说明该混合菌剂具有应用于实际石油污染土壤生物修复的潜力.%The isolation of six strains of petroleum degrading bacteria from contaminated Gansu Longdong Changqing Oilfield serious soil, which were named as A1, A2, A3, A4, A5 and A6 were carried out routine identification, A1, A2 and A3 were bacillus, A4, A6 were Pseudomonas A5, acinetobacter. Get the degradation of petroleum hydrocarbon compound bacteria through fermentation, resurrection, and carried out experiments of microbial remediation of oily sludge. The results show that when the oil content in soil was 50g/kg, adding oil degrading mixed inoculum rate than the degradation efficiency without inoculum, adding 4% agent 81D degradation rate was 90.20% higher than that of control group (add organic fertilizer) the degradation rate of 31.10%, indicating that the mixed bacteria agent is applied to the actual oil the potential for bioremediation of contaminated soil.

  10. THE COMPATIBILITY OF BLENDS OF POLY(VINYL CHLORIDE) OR CHLORINATED POLY(VINYL CHLORIDE) WITH POLY(METHYL METHACRYLATE)

    Institute of Scientific and Technical Information of China (English)

    WANG Qingguo; CHENG Rongshi

    1988-01-01

    IR spectral shifts of carbonyl vibrational absorption for ethyl acetate, which acts analogically as the structural unit of poly(methyl methacrylate), in cyclohexane, chloroform, chlorinated paraffins, poly(vinyl chloride) and chlorinated poly(vinyl chloride) were measured. The results suggest that there are specific interactions between the carbonyl groups and the chlorinated hydrocarbons which could be responsible for the apparent compatibility of poly(vinyl chloride) -poly(methyl methacrylate) and chlorinated poly(vinyl chloride) -poly(methyl methacrylate) blends. Additionally, the effects of the preparation mode of blend films on phase separation and observed compatibility are discussed.

  11. 二氧化氯/TiO2光催化氧化降解碱性品红模拟废水及反应机理%Investigation of Chlorine Dioxide/TiO2 Photocatalytic Oxidative Degradation of Simulated Wastewater Containing Fuchsine and Its Reaction Mechanism

    Institute of Scientific and Technical Information of China (English)

    施来顺; 王晓美

    2012-01-01

    The photocatalyst TiO2 was prepared by dipping-calcination method using silica gel as catalyst support.The chlorine dioxide/TiO2 photocatalyst was used for the photocatalytic oxidation of simulated fuchsine wastewater.The degradation effect of fuchsine by the combination of chlorine dioxide,TiO2 photocatalyst and UV irradiation was confirmed by comparison test.The optimum treatment conditions were as follows:the volume of wastewater containing 150 mg·L-1 fuchsine was 50 mL;ClO2 concentration was 6.14 mg·L-1,pH value was 5.0;the distance between UV lamp and flask was 20 cm;UV irradiation time was 13 min;and photocatalyst dosage was 10 g·L-1.The removal efficiency of fuchsine could reach 80%,compared with 46% of chlorine dioxide chemical oxidation.With UV-vis and FT IR analysis technique,the intermediates in the degradation process were obtained.Fuchsine was degradated into quinone and carboxylic acid,and finally changed into carbon dioxide and water during the photocatalytic oxidation.The degradation reaction mechanism of fuchsine by chlorine dioxide/TiO2 photocatalytic oxidation was proposed.%以硅胶为载体,采用浸渍-焙烧法制备了TiO2光催化剂,并将其用于二氧化氯/TiO2光催化氧化降解碱性品红模拟废水.经对比实验验证了ClO2/TiO2光催化剂/UV照射对碱性品红的氧化降解作用.50 mL质量浓度为150 mg.L-1的碱性品红模拟废水,在pH值为5.0,二氧化氯质量浓度6.14 mg.L-1和10 g.L-1光催化剂条件下,紫外照射距离20 cm,紫外照射时间13 min,碱性品红的去除率可达80%,远远高于二氧化氯化学氧化处理碱性品红的去除率46%.在废水处理过程中,采用紫外可见光谱和红外光谱分析降解产物,碱性品红被氧化降解为醌和羧酸,并进一步降解为二氧化碳和水,提出了二氧化氯/TiO2光催化氧化降解碱性品红废水的反应机理.

  12. Use of a sub-gasket and soft gas diffusion layer to mitigate mechanical degradation of a hydrocarbon membrane for polymer electrolyte fuel cells in wet-dry cycling

    Science.gov (United States)

    Ishikawa, Hiroshi; Teramoto, Takeshi; Ueyama, Yasuhiro; Sugawara, Yasushi; Sakiyama, Yoko; Kusakabe, Masato; Miyatake, Kenji; Uchida, Makoto

    2016-09-01

    The mechanical durability of hydrocarbon (HC) membranes, used for polymer electrolyte fuel cells (PEFCs), was evaluated by the United States Department of Energy (USDOE) stress protocol involving wet-dry cycling, and the degradation mechanism is discussed. The HC membrane ruptured in the edge region of the membrane electrode assembly (MEA) after 300 cycles due to a concentration of the mechanical stress. Post-test analysis of stress-strain measurements revealed that the membrane mechanical strain decreased more than 80% in the edge region of the MEA and about 50% in the electrode region, compared with the pristine condition. Size exclusion chromatography (SEC) indicated that the average molecular weight of the HC polymer increased slightly, indicating some cross-linking, while the IEC decreased slightly, indicating ionomer degradation. As a result of two types of modifications, a sub-gasket (SG) and a soft gas diffusion layer (GDL) in the MEA edge region, the mechanical stress decreased, and the durability increased, the membrane lasting more than 30,000 cycles without mechanical failure.

  13. Application of Metagenomics for Identification of Novel Petroleum Hydrocarbon Degrading Enzymes in Natural Asphalts from the Rancho La Brea Tar Pits

    OpenAIRE

    Baquiran, Jean-Paul Mendoza

    2010-01-01

    Recent studies on the biodiversity of asphalt deposits at the Rancho La Brea Tar Pits in Los Angeles, California have revealed the existence of several hundred new species of bacteria and gene sequences encoding putative novel degradative enzymes (Kim and Crowley, 2007). The presence of fossilized extinct animal remains in the La Brea Tar Pits has led to estimations that these natural asphalt seeps have existed for at least 40,000 years (Akersten et al., 1983). These deposits consist of petro...

  14. Transformation of chlorinated compounds by methanogenic granular sludge

    NARCIS (Netherlands)

    Eekert, van M.H.A.

    1999-01-01

    Chlorinated compounds are an important group of contaminants often found in sediments, groundwater, soils, wastewaters, and off-gasses. Many of these pollutants are found on the EPA list of Priority Pollutants indicating their potential hazard for the environment. Initial degradation can occur via d

  15. Bacterial Community Dynamics and Hydrocarbon Degradation during a Field-Scale Evaluation of Bioremediation on a Mudflat Beach Contaminated with Buried Oil

    OpenAIRE

    Röling, Wilfred F. M.; Milner, Michael G.; Jones, D. Martin; Fratepietro, Francesco; Swannell, Richard P. J.; Daniel, Fabien; Head, Ian M.

    2004-01-01

    A field-scale experiment with a complete randomized block design was performed to study the degradation of buried oil on a shoreline over a period of almost 1 year. The following four treatments were examined in three replicate blocks: two levels of fertilizer treatment of oil-treated plots, one receiving a weekly application of liquid fertilizer and the other treated with a slow-release fertilizer; and two controls, one not treated with oil and the other treated with oil but not with fertili...

  16. Kinetics of petroleum hydrocarbon degradation in soil and diversity of microbial community during composting%石油烃类污染物降解动力学和微生物群落多样性分析

    Institute of Scientific and Technical Information of China (English)

    甄丽莎; 谷洁; 胡婷; 刘晨; 贾凤安; 吕睿

    2015-01-01

    为了探讨不同初始浓度石油污染土壤堆腐化修复机制,以石油降解菌剂和腐熟鸡粪为调理剂,研究了初始浓度分别为5000(T1)、10000(T2)和50000 mg/kg(T3)的石油污染土壤堆腐化修复过程石油烃类污染物降解动力学特征和微生物群落多样性。结果表明:堆腐化修复过程石油烃类污染物降解符合一级反应动力学,反应常数分别为0.012、0.094和0.050 d-1,半衰期分别为6.79、7.37和13.86 d。整个堆腐过程石油烃类污染物平均降解速率分别为112.08、230.05和887.93 mg/(kg·d)。3个处理的孔平均颜色变化率(average well color development)和碳源利用率(除芳香烃类化合物外)随堆腐进程的推进逐渐升高,在堆腐中、后期达到最大,T3处理显著高于T1、T2处理。多聚物类和糖类代谢群是堆腐体系中的优势菌群。主成分分析表明3个处理的微生物群落差异显著(除第9天外),起分异作用的碳源主要是糖类和羧酸类。微生物群落的丰富度指数和均一度指数随堆腐进程的推进逐渐升高并在堆腐后期达到最大,与T1处理相比, T3处理分别高了0.21%和17.64%,差异达到显著水平(P0.05)。堆肥结束时3个处理的种子发芽指数(seed germination index, SGI)分别比堆腐初期提高了18.26%、20.42%和36.41%。该研究结果为黄土高原不同程度石油污染土壤堆腐化修复的应用提供参考依据和理论基础。%In order to investigate the mechanism of bioremediation of petroleum hydrocarbon-contaminated soil by composting, an experiment was conducted with bacteria agent and mature chicken manure as amendment. We studied the kinetics of petroleum hydrocarbon degradation and the diversity of microbial community during the bioremediation of petroleum hydrocarbon-contaminated soil by composting with different concentrations. The concentrations included 5 000 mg/kg (T1), 10 000 mg/kg (T2

  17. Reactions of aqueous chlorine and chlorine dioxide with model food compounds.

    OpenAIRE

    Fukayama, M Y; Tan, H; Wheeler, W B; Wei, C I

    1986-01-01

    Chlorine and chlorine dioxide (ClO2), common disinfecting and bleaching chemicals used in the food industry, are potent oxidizing and chlorinating agents. Unfortunately, little is known about the nature of the reactions of chlorine with organic food constituents. This presentation reviews published information concerning the reactions of chlorine gas (Cl2[g]), aqueous chlorine, and ClO2 with model food compounds, the fate of chlorine during the chlorination of specific food products, and the ...

  18. Photostability of different chlorine photosensitizers

    International Nuclear Information System (INIS)

    In this paper, we report the photodegradation of three different chlorine photosensitizers (Photoditazine®, Radachlorin®, and Foscan®). The photosensitizer degradation was analyzed by changes in the fluorescence spectrum during illumination. The rate of fluorescence variation was normalized to the solution absorption and the photon energy resulting in the determination of the necessary number of photons to be absorbed to induce photosensitizer photodegradation. The parameter for rate of the molecules decay, the photon fluence rate and optical properties of the solution allow us to determine the photosensitizer stability in solution during illumination. The results show that the order of susceptibility for photodegradation rate is: Radachlorin® < Photoditazine® < Foscan®. This difference in the photodegradation rate for Foscan can be explained by the high proportion of aggregates in solution that inhibit the photo-oxidative process that impede the singlet oxygen formation. We hypothesize that there is a correlation between photodegradation rate and photodynamic efficacy witch is governed by the singlet oxygen formation responsible for the most relevant reaction of the cell death photodynamic induction. Then its is important to know the photostability of different types of drugs since the photodegradation rate, the photodegradation as well as the photodynamic efficacy are strong correlated to the oxygen concentration in the tissue

  19. Transformation of phenazone-type drugs during chlorination.

    Science.gov (United States)

    Rodil, Rosario; Quintana, José Benito; Cela, Rafael

    2012-05-01

    Chlorination is one of the most popular disinfection steps for water treatment in Europe. However, chlorine can react with pharmaceuticals and other micropollutants leading to either their elimination or by-products being formed. These by-products are frequently not identified and therefore the consequences of chlorination can be underestimated. In this work, the degradation of two analgesics and antipyretics, phenazone (antipyrine) and propyphenazone, during chlorination was investigated by liquid chromatography-mass spectrometry (LC-MS). A quadrupole-time-of-flight (Q-TOF) system was used to follow the time course of the pharmaceuticals, and also used in the identification of the by-products. The degradation kinetics was investigated at different concentrations of chlorine (1-10 mg/L), bromide (0-100 μg/L) and sample pH (5.7-8.3) by means of a Box-Behnken experimental design. Depending on these factors, half-lives were in the ranges: 0.9-295 s for phenazone and 0.4-173 s for propyphenazone. Also, it was observed that chlorine concentration was a significant factor for propyphenazone, resulting in increased degradation rate as it is increased. The transformation path of these drugs consisted mainly of halogenations, hydroxylations and dealkylations. After several days of reaction two derivatives remained stable for phenazone: chloro-hydroxy-phenazone and N-demethyl-chloro-hydroxy-phenazone and two for propyphenazone: N-demethyl-hydroxy-propyphenazone and N-demethyl-chloro-hydroxy-propyphenazone. Moreover, experiments conducted with real water matrices, tap and surface water, showed that reaction, and formation of by-products, can take place both at the emission source point (household) and during drinking water production. PMID:22381982

  20. The chlorination of cooling water

    International Nuclear Information System (INIS)

    After reviewing the means of fighting biological pollution of cooling water circuits in nuclear power stations, the authors describe the chlorination treatment methods used by EDF. This deals with the massive shock chlorination of the cooling towers and the continuous low-level chlorination of coastal nuclear power stations. In both areas, the Research and Development Board of EDF has carried out and encouraged research with the aim of improving circuit protection, while still protecting the aquatic eco-system against damage that might be caused by waste chlorinated water

  1. Fenton's reagent as a remediation process in water treatment: application to the degradation of polycyclic aromatic hydrocarbons in waters and sewage sludges; La reaction de fenton comme procede de rehabilitation dans le traitement des eaux: application a la degradation des hydrocarbures aromatiques polycycliques dans les eaux et les boues residuaires

    Energy Technology Data Exchange (ETDEWEB)

    Flotron, V.

    2004-05-15

    This study is related to the application of Fenton's reagent to remedy matrices contaminated by polycyclic aromatic hydrocarbons (PAHs). In aqueous solution, the choice of the reagent implementation is important, in order to generate enough radicals to oxidize pollutants. Degradation of the organic compounds is possible, but a large difference in reactivity is observed between 'alternant' and 'non-alternant' PAHs (with a five carbon atoms cycle). Besides, if a few specific precautions are omitted, the PAHs can sorb onto the flask inside surface, and therefore not undergo oxidation. The results on sewage sludges show that under certain conditions (high reagent concentrations), the pollutants can be oxidised although they are adsorbed. Moreover, it appears that the matrix itself plays an important role, as the iron oxides seem to be able to decompose hydrogen peroxide, and thus initiate Fenton reaction. Its application to contaminated soils and sediments is also possible. (author)

  2. Enhanced reductive dechlorination in clay till contaminated with chlorinated solvents

    DEFF Research Database (Denmark)

    Damgaard, Ida

    Chlorinated solvents are among the most frequently found contaminants in groundwater. In fractured media, chlorinated ethenes and ethanes are transported downwards through preferential pathways with subsequent diffusion into the sediment matrix. Due to slow back diffusion it can serve as a long...... the potential for development of degradation throughout the entire clay matrix. When ERD is applied in a low permeability settings one of the major constraints is to obtain the necessary contact between electron donor, bacteria and contaminants to achieve reasonable remediation timeframes. Two injection methods...

  3. Selectivity Studies of Oxygen and Chlorine Dioxide in the Pre-Delignification Stages of a Hardwood Pulp Bleaching Plant

    OpenAIRE

    Barroca, Maria J. M. C.; Marques, Pedro J. T. S.; Seco, Isabel M.; Castro, José Almiro A. M.

    2001-01-01

    This work is concerned with the role of oxygen on the selectivity of chlorine dioxide in the pre-delignification stage of a E. globulus pulp bleaching plant. Its main purpose is to study the selectivity of chlorine dioxide when applied to an oxygen pre-delignified hardwood kraft pulp and to compare it to that of a conventional pre-delignification with chlorine dioxide (D). The intrinsic viscosity and kappa number were used to follow the polysaccharides degradation and the delignification rate...

  4. Derivation of validated methods of sampling and analysis for intermediate and final products of the anaerobic material utilization of volatile chlorinated hydrocarbons (LCFC) in groundwater in the context of analyses of contaminated soils; Ableitung validierter Probenahme- und Analysenmethoden fuer Zwischen- und Endprodukte der anaeroben Stoffverwertungsprozesse von Leichtfluechtigen Chlorierten Kohlenwasserstoffen (LCKW) im Grundwasser im Rahmen von Altlastenuntersuchungen

    Energy Technology Data Exchange (ETDEWEB)

    Dorgerloh, Ute; Becker, Roland; Win, Tin [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany); Theissen, Hubert [IMAGO GbR (Germany)

    2010-06-17

    The results of the project ''Methods of sampling and analysis of intermediate and final products of the anaerobic degradation of volatile halogenated hydrocarbons in groundwater in frame of analysis of contaminated sites'' of the German Federal States Program ''Water, Soil, Waste'' (Laenderfinanzierungsprogramm ''Wasser, Boden, Luft'') LFP B2.08 are presented in these report. Different methods of sampling and analysis for the determination of hydrogen, methane, ethene and vinyl chloride in groundwater are developed and validated: For the sampling are described and discussed: i. active sampling: purge and sample of water samples and purging of solvated gases in groundwater in gas sampling tubes ii. passive sampling: diffusion sampling in polyethylene diffusion bags (PDB) and plastic syringes as diffusion sampler for solvated gases The use of active (purge and sample, downhole sampler) and passive (diffusion sampling) sampling techniques for the quantification of VOC, ethene, and methane are evaluated from the viewpoint of public authorities and regarding the reproducibility of measurement results. Based on a groundwater contaminated with trichloroethene, 1,2-dichloroethene, and vinyl chloride it is shown that passive sampling is restricted by low groundwater flow and biological activity inside the well casing. Therefore, active sampling is to be preferred in case of unknown or insufficient flow conditions in the aquifer. The methods of chromatography for the determination of the compounds are validated and compared with other appropriate analytical methods: I. Headspace-GC-FID for the determination of methane, ethene and vinyl chloride in water of the purged sample (i) and the water of the PDB (ii) II. Direct injection - GC-PDD for the determination of hydrogen from the collected gas samples of the gas sampling tube (i) and the plastic syringes (ii) The gas chromatographic procedure for vinyl chloride using

  5. Photophysical properties and localization of chlorins substituted with methoxy groups, hydroxyl groups and alkyl chains in liposome-like cellular membrane

    Energy Technology Data Exchange (ETDEWEB)

    Al-Omari, S [Department of Physics, Hashemite University, Zarqa 13115 (Jordan)

    2007-06-01

    Some of the photophysical properties (stationary absorbance and fluorescence, fluorescence decay times and singlet oxygen quantum yields) of chlorins substituted with methoxy groups, hydroxyl groups and hydrocarbonic chains were studied in ethanol and dipalmitoyl-phosphatidylcholine (DPPC) liposomes using steady-state and time-resolved fluorescence spectroscopies. The photophysical behaviors of the chlorins in liposomes like cellular membrane were compared with those obtained from chlorin-liposome systems delivered to Jurkat cells in order to select potent photosensitizers for the photodynamic treatment of cancer. The localization of the studied chlorins inside liposomes was found to depend strongly on the substituents of chlorins. Absorption spectra of chlorins embedded in DPPC-liposomes have been recorded in the temperature range of 20-70 deg. C. It is demonstrated that the location of the chlorin molecules depends on the phase state of the phospholipids. These observations are confirmed by the fluorescence lifetimes, singlet oxygen lifetimes and singlet oxygen quantum yields results.

  6. Photophysical properties and localization of chlorins substituted with methoxy groups, hydroxyl groups and alkyl chains in liposome-like cellular membrane

    International Nuclear Information System (INIS)

    Some of the photophysical properties (stationary absorbance and fluorescence, fluorescence decay times and singlet oxygen quantum yields) of chlorins substituted with methoxy groups, hydroxyl groups and hydrocarbonic chains were studied in ethanol and dipalmitoyl-phosphatidylcholine (DPPC) liposomes using steady-state and time-resolved fluorescence spectroscopies. The photophysical behaviors of the chlorins in liposomes like cellular membrane were compared with those obtained from chlorin-liposome systems delivered to Jurkat cells in order to select potent photosensitizers for the photodynamic treatment of cancer. The localization of the studied chlorins inside liposomes was found to depend strongly on the substituents of chlorins. Absorption spectra of chlorins embedded in DPPC-liposomes have been recorded in the temperature range of 20-70 deg. C. It is demonstrated that the location of the chlorin molecules depends on the phase state of the phospholipids. These observations are confirmed by the fluorescence lifetimes, singlet oxygen lifetimes and singlet oxygen quantum yields results

  7. Fluoridation of gaseous phase chlorinated hydrocarbons in presence of chromium oxide-based catalysts. Effect of doping substance addition; Fluoration d'hydrocarbures chlores en phase gazeuse en presence de catalyseurs a base d'oxyde de chrome. Effet de l'ajout de dopant

    Energy Technology Data Exchange (ETDEWEB)

    Loustaunau, A.

    2003-11-01

    The preparation of various hydro-fluorocarbons (HFC), like CF{sub 3}CH{sub 2}F, CF{sub 3}CHF{sub 2} and CH{sub 2}F{sub 2}, has been studied at temperatures of 380 deg. C and 250 deg. C in gaseous phase by catalytic fluoridation of the corresponding chlorinated hydrocarbons. The addition of doping substances like zinc, nickel or magnesium to fluorinated alumina supported chromium oxide-based catalysts, has been particularly examined in order to favour the main fluoridation reaction (by simple Cl/F exchange) with respect to secondary reactions (de-hydro-fluoridation and Deacon). Only the addition of small amounts of Zn (Zn/(Zn+Cr) = 0.15) allows to promote the fluoridation reaction and to inhibit the secondary reactions. This effect is enhanced when the molecule is less reactive and when the quantity of matter at the surface of the fluorinated alumina is low. Therefore, the promoting effect is more important in presence of CF{sub 3}CH{sub 2}Cl than in presence of CF{sub 3}CHCl{sub 2} and CH{sub 2}Cl{sub 2}. This positive effect of zinc may result from the formation of a mixed ZnCr{sub 2}O{sub 4} phase during the preparation of the catalyst (evidenced by X-ray photoelectron spectroscopy (XPS)) which may have modified the chemical properties of chromium atoms. Moreover, the XPS and electron microscopy characterizations indicate that the presence of zinc (contrary to nickel and magnesium) may allow a better dispersion of the active chromium atoms for Cl/F exchanges after fluoridation of the catalyst. Those may correspond to the presence of very fluorinated species, like 'Cr-F', and oxi-fluorinated like 'CrOF'. Thus, in the presence of a small amount of metals at the surface of the support, the formation of these different species is favoured. (J.S.)

  8. Environmentally acceptable incineration of chlorinated chemical waste: review of theory and practice

    NARCIS (Netherlands)

    De Zeeuw, M.A.; Lemkowitz, S.M.

    1987-01-01

    Chlorinated hydrocarbons in the form of chemical waste, represent a threat to the environment and public health of the world. Their proper handling, removal and destruction is critical to long term safety. Increasingly strict government legislation is leading to an increase in the quantity of chlori

  9. Chlorine isotope composition in chlorofluorocarbons CFC-11, CFC-12 and CFC-113 in firn, stratospheric and tropospheric air

    NARCIS (Netherlands)

    Allin, S. J.; Laube, J. C.; Witrant, E.; Kaiser, J.; McKenna, E.; Dennis, P.; Mulvaney, R.; Capron, E.; Martinerie, P.; Roeckmann, Thomas; Blunier, T.; Schwander, J.; Fraser, P. J.; Langenfelds, R. L.; Sturges, W. T.

    2015-01-01

    The stratospheric degradation of chlorofluorocarbons (CFCs) releases chlorine, which is a major contributor to the destruction of stratospheric ozone (O-3). A recent study reported strong chlorine isotope fractionation during the breakdown of the most abundant CFC (CFC-12, CCl2F2, Laube et al., 2010

  10. Chlorine Analysis by Diode Laser Atomic Absorption Spectrometry

    Institute of Scientific and Technical Information of China (English)

    Joachim Koch; Aleksandr Zybin; Kay Niemax

    2000-01-01

    The general characteristics of Diode Laser Absorption Spectrometry (DLAAS) in low pressure plasmas particulary with respect to the detection of non-metals are comprehensively recapitulated and discussed. Furthermore, a detector, which is based on DLAAS in a microwave-induced low pressure plasma as an alternative technique for halogene-specific analysis of volatile compounds and polymeric matrices is described. The analytical capability of the technique is demonstrated on the chlorine-specific analysis of ablated polymer fragments as well as gas chromatographically separated hydrocarbons. Since the measurements were carried out by means of a balanced-heterodyne detection scheme, different technical noise contributions, such as laser excess and RAM noise could efficiently be suppressed and the registered absorption was limited only by the principal shot noise. Thus, in the case of the polymer analysis a chlorine-specific absolute detection limit of 10 pg could be achieved. Furthermore, fundamental investigations concerning the influence of hydrocarbons on the dissociation capability of the microwave induced plasma were performed. For this purpose, the carbon-, chlorine-and hydrogen-specific stoichiometry of the compounds were empirically determined. Deviations from the exspected proportions were found to be insignificant, implying the possibility of internal standardization relative to the response of a reference sample.

  11. Inactivation of Chironomid Larvae with Chlorine Dioxide and Chlorine

    Institute of Scientific and Technical Information of China (English)

    SUN Xin-bin; CUI Fu-yi

    2008-01-01

    Chironomid larvae propagate prolifically in eutrophic water body and they cannot be exterminated by conventional disinfection process.The inactivation effects of chlorine and chlorine dioxide on Chironomid larvae were investigated and some boundary values in practice were determined under conditions of various oxidant dosage,organic precursor concentration and pH value.In addition,removal effect of differmt pre-oxidation combined with coagulation process on Chironomid larvae in law water was evaluated.It was found that chlorine dioxide possessed better inactivation effect than chlorine.Complete inactivation of Chironomid larvae in raw water was resulted by 1.5mg/L of chlorine dioxide with 30min of contact time. Additionally,the ocgallic precursor concentration,pH value had little influence on the inactivation effect.The coagulation jar test showed that Chironomid larvae in the raw water could be completely ronxwed by chlorine dioxide pre-oxidation in combination with the omgulation process at chlorine dioxide dosage of 0.8 mg/L.

  12. Ultrafast Third-Order Nonlinear Optical Spectroscopy of Chlorinated Hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Napoleon Thantu; Robert S. Schley

    2003-09-01

    Time-resolved Raman induced Kerr effect spectroscopy in the optical heterodyne detection configuration has been employed to investigate intermolecular, intramolecular, and reorientational dynamics in neat trichloroethylene (TCE). The reorientation time constant is directly measured from the time-resolved data, while Fourier transformation of the time-resolved data yields the intermolecular and intramolecular vibrational spectrum. Use of ultrashort, femtosecond pulses enables excitation of depolarized Raman-active transitions between 1 and 500 cm-1. The intramolecular vibrations have been identified using a previous assignment. The limitations imposed by the laser and detector noise, and other nonlinear optical processes that are manifest at high pulse intensities, on the use of this time-domain technique for performing chemical species detection are discussed using carbon tetrachloride as an example.

  13. Chlorination of tramadol: Reaction kinetics, mechanism and genotoxicity evaluation.

    Science.gov (United States)

    Cheng, Hanyang; Song, Dean; Chang, Yangyang; Liu, Huijuan; Qu, Jiuhui

    2015-12-01

    Tramadol (TRA) is one of the most detected analgesics in environmental matrices, and it is of high significance to study the reactivity of TRA during chlorination considering its potential toxicity to the environment. The chlorine/TRA reaction is first order with respect to the TRA concentration, and a combination of first-order and second-order with respect to chlorine concentration. The pH dependence of the observed rate constants (kobs) showed that the TRA oxidation reactivity increased with increasing pH. kobs can be quantitatively described by considering all active species including Cl2, Cl2O and HOCl, and the individual rate constants of HOCl/TRA(0), HOCl/TRAH(+), Cl2/TRA and Cl2O/TRA reactions were calculated to be (2.61±0.29)×10(3)M(-1)s(-1), 14.73±4.17M(-1)s(-1), (3.93±0.34)×10(5)M(-1)s(-1) and (5.66±1.83)×10(6)M(-1)s(-1), respectively. Eleven degradation products were detected with UPLC-Q-TOF-MS, and the corresponding structures of eight products found under various pH conditions were proposed. The amine group was proposed to be the initial attack site under alkaline pH conditions, where reaction of the deprotonated amine group with HOCl is favorable. Under acidic and neutral pH conditions, however, two possible reaction pathways were proposed. One is an electrophilic substitution on the aromatic ring, and another is an electrophilic substitution on the nitrogen, leading to an N-chlorinated intermediate, which can be further oxidized. Finally, the SOS/umu test showed that the genotoxicity of TRA chlorination products increased with increasing dosage of chlorine, which was mostly attributed to the formation of some chlorine substitution products.

  14. Kinetic double-layer model of aerosol surface chemistry and gas-particle interactions (K2-SURF: degradation of polycyclic aromatic hydrocarbons exposed to O3, NO2, H2O, OH and NO3

    Directory of Open Access Journals (Sweden)

    U. Pöschl

    2009-09-01

    Full Text Available We present a kinetic double-layer surface model (K2-SURF that describes the degradation of polycyclic aromatic hydrocarbons (PAHs on aerosol particles exposed to ozone, nitrogen dioxide, water vapor, hydroxyl and nitrate radicals. The model is based on multiple experimental studies of PAH degradation and on the PRA framework (Pöschl et al., 2007 for aerosol and cloud surface chemistry and gas-particle interactions. For a wide range of substrates, including solid and liquid organic and inorganic substances (soot, silica, sodium chloride, octanol/decanol, organic acids, etc., the concentration- and time-dependence of the heterogeneous reaction between PAHs and O3 can be efficiently described with a Langmuir-Hinshelwood-type mechanism. Depending on the substrate material, the Langmuir adsorption constants for O3 vary over three orders of magnitude (Kads,O3≈10−15–10−13 cm3, and the second-order rate coefficients for the surface layer reaction of O3 with different PAH vary over two orders of magnitude (kSLR,PAH,O3≈10−18–10−17 cm2 s−1. The available data indicate that the Langmuir adsorption constants for NO2 are similar to those of O3, while those of H2O are several orders of magnitude smaller (Kads,H2O≈10−18–10−17 cm3. The desorption lifetimes and adsorption enthalpies inferred from the Langmuir adsorption constants suggest chemisorption of NO2 and O3 – possibly in the form of O atoms – and physisorption of H2O. The K2-SURF model enables the calculation of ozone uptake coefficients, γO3, and of PAH concentrations in the quasi-static particle surface layer. Competitive adsorption and chemical transformation of the surface (aging lead to a strong non-linear dependence of γO3 on time and gas phase composition, with different characteristics under dilute atmospheric and concentrated laboratory conditions. Under typical ambient conditions, γO3 of PAH-coated aerosol particles are expected to be in the range of 10−6–10

  15. Monitoring of the aerobe biodegradation of chlorinated organic solvents by stable isotope analysis

    Science.gov (United States)

    Horváth, Anikó; Futó, István; Palcsu, László

    2014-05-01

    Our chemical-biological basic research aims to eliminate chlorinated environmental contaminants from aquifers around industrial areas in the frame of research program supported by the European Social Fund (TÁMOP-4.2.2.A-11/1/KONV-2012-0043). The most careful and simplest way includes the in situ biodegradation with the help of cultured and compound specific strains. Numerous members of Pseudomonas bacteria are famous about function of bioremediation. They can metabolism the environmental hazardous chemicals like gas oils, dyes, and organic solvents. Our research based on the Pseudomonas putida F1 strain, because its ability to degrade halogenated hydrocarbons such as trichloroethylene. Several methods were investigated to estimate the rate of biodegradation, such as the measurement of the concentration of the pollutant along the contamination pathway, the microcosm's studies or the compound specific stable isotope analysis. In this area in the Transcarpathian basin we are pioneers in the stable isotope monitoring of biodegradation. The main goal is to find stable isotope fractionation factors by stable isotope analysis, which can help us to estimate the rate and effectiveness of the biodegradation. The subsequent research period includes the investigation of the method, testing its feasibility and adaptation in the environment. Last but not least, the research gives an opportunity to identify the producer of the contaminant based on the stable isotope composition of the contaminant.

  16. 盐碱土壤多环芳烃降解菌群筛选及其降解特性%Screening and Biodegradation Characteristics of Polycyclic Aromatic Hydrocarbons-Degrading Consortium From Saline-Alkali Soil

    Institute of Scientific and Technical Information of China (English)

    宋立超; 刘灵芝; 李培军; 刘宛; 张玉龙

    2012-01-01

    为了强化多环芳烃(PAHs)污染盐碱土壤原位微生物修复的应用,并提供高效的菌种资源,从天津大港油田盐碱化的油污土壤中富集分离出1组高效降解菲、芘的耐盐碱菌群,分离获得可培养优势细菌5株、真菌3株,考察了该菌群对菲、芘的降解效果,并进行了其对菲、芘降解特性分析.结果表明,该菌群在菲、芘质量浓度分别为25、50和75 mg/L的液体无机盐培养基中培养15 d,菲、芘的降解率分别达到75.3%和53.6%、56.6%和52.0%、25.2%和13.6%;该菌群对菲、芘降解具有较广泛的盐质量分数和pH值范围,在菲、芘初始质量浓度各为50 mg/L,最适盐质量分数0~2%,最适pH值8.6条件下,添加质量分数0.4%葡萄糖培养15d后,菲、芘的降解率显著提高,达到92.1%和65.8%.细菌16S rDNA和真菌18S rDNA测序结果表明,该菌群由叶杆菌属(Phyllobacterium)、假单胞菌属(Pseudomonas)、盐单胞属(Halomonas)、泛菌属(Pantoea)和青霉属(Penicillium)、双曲孢属(Sigmoidea)、胶孢炭疽属(Colletotrichum)组成.%The salt and alkaline endurable microbial consortium of degrading phenanthrene and pyrene effectively was developed from oil-contaminated saline-alkali soil of Tianjin Dagang oil field to intensify the application of situ bioremediation of polycyclic aromatic hydrocarbons in saline-alkaline soil and to provide highly effective microorganisms resources. Five cultivable dominate bacterium strains and three fungi strains through separation were obtained, and their degradation characteristics for phenanthrene and pyrene were analyzed. The degradation rates of phenanthrene and pyrene with 25, 50 and 75 mg/L initial concentration by the microbial consortium in liquid mineral medium after 15 d cultivation were 75. 3% and 53. 6%, 56. 6% and 52. 0%, 25. 2% and 13.6% respectively, meanwhile, when the initial concentration of phenanthrene and pyrene was 50 mg/L, respectively, the most

  17. Biodegradation of chlorinated solvents in a water unsaturated topsoil

    DEFF Research Database (Denmark)

    Borch, T.; Ambus, P.; Laturnus, F.;

    2003-01-01

    In order to investigate topsoils as potential sinks for chlorinated solvents from the atmosphere, the degradation of trichloromethane (CHCl3), 1,1,1-trichloroethane (CH3CCl3), tetrachloromethane (CCl4), trichloroethene (C2HCl3) and tetrachloroethene (C2Cl4) was studied in anoxic laboratory experi...... after 16 days. Based on the results in this study, we conclude that anaerobic topsoils are potential sinks for these contaminants, and that a natural attenuation potential exists, even in water unsaturated topsoils. (C) 2003 Elsevier Science Ltd. All rights reserved....... experiments designed to simulate denitrifying conditions in water unsanstrated by measuring the release of N-15 in N-2 to the headspace from added N-15 labeled nitrate. The degradation of chlorinated aliphatic compounds was followed by measuring their concentrations in the headspace above the soil...

  18. Identification and characterization of a novel hydrocarbon-degrading Marinobacter sp.PY97S%一株石油烃降解菌新种Marinobacter sp.PY97S的鉴定

    Institute of Scientific and Technical Information of China (English)

    李倩; 崔志松; 赵爱芬; 高伟; 郑立

    2011-01-01

    [目的]为了对1株从黄海沉积物中分离到的石油烃降解菌新种PY97S进行分类学鉴定.[方法]采用16S rRNA基因序列同源性分析、生理生化指标测定、抗生素抗性实验,DNA G+C含量测定、全细胞脂肪酸组成测定、碳源利用实验、呼吸醒测定以及DNA杂交实验等多种方法对该菌株进行鉴定,并通过降解实验测定其对烷烃的利用情况.[结果]菌株PY97S为海杆菌(Marinobacter),革兰氏阴性,接触酶阳性,氧化酶阳性,主要呼吸醌为Q-9.在GenBank中与其16S rRNA基因序列相似度最高的模式株为Marinobacter koreensisDD-M3T(96.93%),两者DNA-DNA同源性仅为46.7%.菌株PY97S的温度生长范围为15℃-35℃(最适为30℃),NaCl浓度生长范围是0-10%(最适为0%),初始pH生长范围为pH 6.0-9.0(最适为初始pH7.0).该菌株可以利用多种糖类和有机酸类的碳源,并对氨苄青霉素、氧哌嗪青霉素等多种抗生素敏感.其DNA G+C含量为48.2 mol%.其主要脂肪酸组成为2-methyl C15∶0(29.97%)、C16∶1ω7c(27.22%)、C12∶0(22.22%)和C16∶1ω9c(5.73%).[结论]菌株PY97S是1株能够降解多种多环芳烃和烷烃的海洋石油烃降解菌新种,具有应用到溢油污染海洋环境生物修复的潜力.%[Objective]To identify and characterize a hydrocarbon-degrading bacterium isolated from the sediment of the Yellow Sea.[Methods]We used 16S rRNA gene sequences based phylogenetic analysis, physiological and biochemical characterization, DNA G + C content assaying, determination of cellular fatty acids, testing of carbon sources and respiratory lipoquinone and experiment of DNA-DNA relatedness.Its capability of degrading aliphatic hydrocarbons in 0NR7a media supplemented with nine n-alkanes, separately, as sole source of carbon and energy was further determined.[Results]The Gram-negative isolate PY97S was a member of the genus Marinobacter, catalase-and oxidase-positive, and with Q-9 as its predominant respiratory lipoquinone

  19. Grundfoss: Chlorination of Swimming Pools

    DEFF Research Database (Denmark)

    Hjorth, Poul G.; Hogan, John; Andreassen, Viggo

    1998-01-01

    Grundfos asked for a model, describing the problem of mixing chemicals, being dosed into water systems, to be developed. The application of the model should be dedicated to dosing aqueous solution of chlorine into swimming pools.......Grundfos asked for a model, describing the problem of mixing chemicals, being dosed into water systems, to be developed. The application of the model should be dedicated to dosing aqueous solution of chlorine into swimming pools....

  20. Chlorine/UV Process for Decomposition and Detoxification of Microcystin-LR.

    Science.gov (United States)

    Zhang, Xinran; Li, Jing; Yang, Jer-Yen; Wood, Karl V; Rothwell, Arlene P; Li, Weiguang; Blatchley Iii, Ernest R

    2016-07-19

    Microcystin-LR (MC-LR) is a potent hepatotoxin that is often associated with blooms of cyanobacteria. Experiments were conducted to evaluate the efficiency of the chlorine/UV process for MC-LR decomposition and detoxification. Chlorinated MC-LR was observed to be more photoactive than MC-LR. LC/MS analyses confirmed that the arginine moiety represented an important reaction site within the MC-LR molecule for conditions of chlorination below the chlorine demand of the molecule. Prechlorination activated MC-LR toward UV254 exposure by increasing the product of the molar absorption coefficient and the quantum yield of chloro-MC-LR, relative to the unchlorinated molecule. This mechanism of decay is fundamentally different than the conventional view of chlorine/UV as an advanced oxidation process. A toxicity assay based on human liver cells indicated MC-LR degradation byproducts in the chlorine/UV process possessed less cytotoxicity than those that resulted from chlorination or UV254 irradiation applied separately. MC-LR decomposition and detoxification in this combined process were more effective at pH 8.5 than at pH 7.5 or 6.5. These results suggest that the chlorine/UV process could represent an effective strategy for control of microcystins and their associated toxicity in drinking water supplies. PMID:27338715

  1. Aromatic polycyclic hydrocarbons in the environment - I - Sources. Les hydrocarbures aromatiques polycycliques chlores presents dans l'environnement - I - Sources

    Energy Technology Data Exchange (ETDEWEB)

    Bard, D. (Electricite de France (EDF), 75 - Paris (France))

    Chlorinated aromatic polycyclic hydrocarbons, which include polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorobiphenyls (PCBs) and others, are persistent, ubiquitous compounds in the environment of industrialized countries. In this paper, we present a short review of the known sources of these compounds. These include industrial sources, such as processing, accidents, and waste disposal of chlorophenols, diphenylethers herbicides, chlorinated aliphatics and PCBs processing: petroleum refining industry, municipal and industrial waste incineration; reclamation or recycling of copper and steel; pulp and paper cork, pesticides (hexachlorocyclohexanes-HCH) and metallurgical (nickel and magnesium) processing. In addition, these compounds appear as being formed naturally in traces quantities in many circumstances of organic matter combustion or pyrolysis. As a result, they have been found in chimney soots, stoves... They are also produced in car exhausts. Another natural mechanism of formation could be the photochemical degradation of higher chlorinated isomers to lower ones. Since it cannot be excluded that these compounds may be carcinogenic for humans at low doses, efforts should be made to limit to as low as reasonably achievable the inputs to the environment of HAPC from artificial origin. (Author). 46 refs., 8 tabs.

  2. EFFECTS OF OZONE, CHLORINE DIOXIDE, CHLORINE, AND MONOCHLORAMINE ON CRYTOSPORIDIUM PARVUM OOCYST VIABILITY

    Science.gov (United States)

    Purified Cryptosporiodium parvum oocysts were exposed to ozone, chlorine dioxide, chlorine, and monochloramine. Excystation and mouse infectivity were compareatively evaluated to assess oocyst viability. Ozone and chlorine dioxide more effectively inactivated oocysts than chlor...

  3. Kinetic study of neodymium oxide chlorination with gaseous chlorine

    Energy Technology Data Exchange (ETDEWEB)

    Bosco, Marta V., E-mail: marta.bosco@cab.cnea.gov.ar [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina); Fouga, Gaston G. [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina); Complejo Tecnologico Pilcaniyeu, Comision Nacional de Energia Atomica, Avenida Bustillo 9500, CP 8400 San Carlos de Bariloche (Argentina); Bohe, Ana E. [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina); Complejo Tecnologico Pilcaniyeu, Comision Nacional de Energia Atomica, Avenida Bustillo 9500, CP 8400 San Carlos de Bariloche (Argentina); Centro Regional Universitario Bariloche, Universidad Nacional del Comahue, CP 8400 San Carlos de Bariloche (Argentina)

    2012-07-20

    Highlights: Black-Right-Pointing-Pointer We analyze the kinetics of the neodymium oxide chlorination reactions. Black-Right-Pointing-Pointer For temperatures below 425 Degree-Sign C the system is under chemical control. Black-Right-Pointing-Pointer The formation of oxychloride progresses through a nucleation and growth mechanism. Black-Right-Pointing-Pointer A reaction order of 0.40 with respect to chlorine partial pressure was determined. Black-Right-Pointing-Pointer An activation energy of 161 {+-} 4 kJ mol{sup -1} was determined. - Abstract: The kinetics of the chlorination of neodymium oxide has been investigated by thermogravimetry between 312 Degree-Sign C and 475 Degree-Sign C, and for partial pressures of chlorine ranging from 10 kPa to 50 kPa. The starting temperature for the reaction of neodymium oxide with chlorine was determined to be about 250 Degree-Sign C, leading to neodymium oxychloride as product. The results showed that, for temperatures below 425 Degree-Sign C, the system is under chemical control and the formation of the oxychloride progresses through a nucleation and growth mechanism. The influence of chlorine mass transport through the bulk gas phase and through the boundary layer on the overall reaction rate was analyzed. In the absence of these two mass-transfer steps, a reaction order of 0.39 with respect to chlorine partial pressure, and an activation energy of 161 {+-} 4 kJ mol{sup -1} were determined. A complete rate equation has been successfully developed.

  4. Mineralisation of target hydrocarbons in three contaminated soils from former refinery facilities

    Energy Technology Data Exchange (ETDEWEB)

    Towell, Marcie G. [Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ (United Kingdom); Bellarby, Jessica; Paton, Graeme I. [Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 3UU (United Kingdom); Coulon, Frederic; Pollard, Simon J.T. [School of Applied Sciences, Sustainable Systems Department, Cranfield University, Cranfield (United Kingdom); Semple, Kirk T., E-mail: k.semple@lancaster.ac.u [Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ (United Kingdom)

    2011-02-15

    This study investigated the microbial degradation of {sup 14}C-labelled hexadecane, octacosane, phenanthrene and pyrene and considered how degradation might be optimised in three genuinely hydrocarbon-contaminated soils from former petroleum refinery sites. Hydrocarbon mineralisation by the indigenous microbial community was monitored over 23 d. Hydrocarbon mineralisation enhancement by nutrient amendment (biostimulation), hydrocarbon degrader addition (bioaugmentation) and combined nutrient and degrader amendment, was also explored. The ability of indigenous soil microflora to mineralise {sup 14}C-target hydrocarbons was appreciable; {>=}16% mineralised in all soils. Generally, addition of nutrients or degraders increased the rates and extents of mineralisation of {sup 14}C-hydrocarbons. However, the addition of nutrients and degraders in combination had a negative effect upon {sup 14}C-octacosane mineralisation and resulted in lower extents of mineralisation in the three soils. In general, the rates and extents of mineralisation will be dependent upon treatment type, nature of the contamination and adaptation of the ingenious microbial community. - Research highlights: Indigenous microbes actively degrade {sup 14}C-hydrocarbons in field contaminated soils. Addition of nutrients or degraders enhance mineralisation in contaminated soils. Biodegradation is related to the presence of hydrocarbons and microbial activity. - Bioremediation strategy, native hydrocarbon concentrations and prior exposure histories of the microbial community influence hydrocarbon degradation in soil.

  5. Hydrocarbons degrading yeasts from Cochin backwater

    Digital Repository Service at National Institute of Oceanography (India)

    Prabhakaran, N.; Sivadas, P.

    stream_size 5 stream_content_type text/plain stream_name J_Mar_Biol_Assoc_India_37_226.pdf.txt stream_source_info J_Mar_Biol_Assoc_India_37_226.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset=ISO-8859-1 ...

  6. Les hydrocarbures aromatiques polycycliques dans l'environnement. Deuxième partie : La dégradation par voie microbienne Polycyclic Aromatic Hydrocarbons in the Environment. Part Two: Microbial Degradation

    Directory of Open Access Journals (Sweden)

    Bouchez M.

    2006-11-01

    Full Text Available La microbiologie de la dégradation des hydrocarbures aromatiques polycycliques (HAP est un domaine de recherche en plein développement. C'est à la fois le devenir dans l'environnement de ces composés ubiquistes et génotoxiques et l'utilisation de procédés microbiologiques de dépollution des sols industriels contaminés par ces produits qui motivent cet intérêt. On présente ici une synthèse des connaissances actuelles dans ce domaine. Les organismes dégradeurs sont essentiellement les bactéries et les champignons. Le processus de dégradation, aérobie, est initié par des oxygénases. Les bactéries utilisent les HAP de deux à quatre cycles comme substrats de croissance, ce qui conduit à leur minéralisation. Les champignons, lignolytiques et non lignolytiques, attaquent les HAP par cométabolisme, ce que font également les bactéries. L'ensemble des micro-organismes dégradant les HAP, et les voies métaboliques impliquées, sont présentés. Le mode d'accession des micro-organismes à leurs substrats très peu solubles est un point important. Les études menées avec les bactéries ont montré l'existence de deux mécanismes, le transfert par solubilisation dans la phase aqueuse et l'accession interfaciale directe. Un autre aspect présenté est le devenir des HAP, en termes de bilans carbone, lors de la dégradation bactérienne de HAP individuels et de mélanges de HAP. Des taux de minéralisation élevés peuvent être obtenus. Dans le cas des mélanges, ces taux élevés impliquent la mise en oeuvre de microflores complexes où le cométabolisme joue un rôle important. Les progrès accomplis ces dernières années conduisent à ne plus considérer les HAP comme des composés intrinsèquement récalcitrants à la biodégradation. Dans l'environnement, un facteur important limitant la dégradation des HAP est leur accessibilité aux micro-organismes. The microbiology of the degradation of polycyclic aromatic hydrocarbons

  7. Biodegradation of petroleum hydrocarbons in hypersaline environments

    OpenAIRE

    Luiz Fernando Martins; Raquel Silva Peixoto

    2012-01-01

    Literature on hydrocarbon degradation in extreme hypersaline media presents studies that point to a negative effect of salinity increase on hydrocarbonoclastic activity, while several others report an opposite tendency. Based on information available in the literature, we present a discussion on the reasons that justify these contrary results. Despite the fact that microbial ability to metabolize hydrocarbons is found in extreme hypersaline media, indeed some factors are critical for the occu...

  8. Biodegradation of Petroleum Hydrocarbons in Soil

    OpenAIRE

    MR Mehrasbi; B Haghighi; M.Shariat; S Naseri; Naddafi, K

    2003-01-01

    Biodegradation of petroleum hydrocarbons (20 g/kg dw soil) was investigated in 3 media, differing in the kind of petroleum fractions. In the laboratory experiments, during 5 months, the activities of petroleum hydrocarbon-degrading microorganisms and dehydrogenase activity of soil was determined. Gas chromatographic analysis showed the biological decontaminations for gas oil, kerosene and synthetic mixture (gas oil, kerosene and furnace oil) are 60 %, 36 % and 55 %, respectively. Dehydrogenas...

  9. Bioremediation of petroleum hydrocarbons: catabolic genes, microbial communities, and applications.

    Science.gov (United States)

    Fuentes, Sebastián; Méndez, Valentina; Aguila, Patricia; Seeger, Michael

    2014-06-01

    Bioremediation is an environmental sustainable and cost-effective technology for the cleanup of hydrocarbon-polluted soils and coasts. In spite of that longer times are usually required compared with physicochemical strategies, complete degradation of the pollutant can be achieved, and no further confinement of polluted matrix is needed. Microbial aerobic degradation is achieved by the incorporation of molecular oxygen into the inert hydrocarbon molecule and funneling intermediates into central catabolic pathways. Several families of alkane monooxygenases and ring hydroxylating dioxygenases are distributed mainly among Proteobacteria, Actinobacteria, Firmicutes and Fungi strains. Catabolic routes, regulatory networks, and tolerance/resistance mechanisms have been characterized in model hydrocarbon-degrading bacteria to understand and optimize their metabolic capabilities, providing the basis to enhance microbial fitness in order to improve hydrocarbon removal. However, microbial communities taken as a whole play a key role in hydrocarbon pollution events. Microbial community dynamics during biodegradation is crucial for understanding how they respond and adapt to pollution and remediation. Several strategies have been applied worldwide for the recovery of sites contaminated with persistent organic pollutants, such as polycyclic aromatic hydrocarbons and petroleum derivatives. Common strategies include controlling environmental variables (e.g., oxygen availability, hydrocarbon solubility, nutrient balance) and managing hydrocarbon-degrading microorganisms, in order to overcome the rate-limiting factors that slow down hydrocarbon biodegradation.

  10. Bioremediation via in situ microbial degradation of organic pollutants.

    Science.gov (United States)

    Vogt, Carsten; Richnow, Hans Hermann

    2014-01-01

    Contamination of soil and natural waters by organic pollutants is a global problem. The major organic pollutants of point sources are mineral oil, fuel components, and chlorinated hydrocarbons. Research from the last two decades discovered that most of these compounds are biodegradable under anoxic conditions. This has led to the rise of bioremediation strategies based on the in situ biodegradation of pollutants. Monitored natural attenuation is a concept by which a contaminated site is remediated by natural biodegradation; to evaluate such processes, a combination of chemical and microbiological methods are usually used. Compound specific stable isotope analysis emerged as a key method for detecting and quantifying in situ biodegradation. Natural attenuation processes can be initiated or accelerated by manipulating the environmental conditions to become favorable for indigenous pollutant degrading microbial communities or by adding externally breeded specific pollutant degrading microorganisms; these techniques are referred to as enhanced natural attenuation. Xenobiotic micropollutants, such as pesticides or pharmaceuticals, contaminate diffusively large areas in low concentrations; the biodegradation pattern of such contaminations are not yet understood. PMID:24337042

  11. In situ aerobic cometabolism of chlorinated solvents: a review.

    Science.gov (United States)

    Frascari, Dario; Zanaroli, Giulio; Danko, Anthony S

    2015-01-01

    The possible approaches for in situ aerobic cometabolism of aquifers and vadose zones contaminated by chlorinated solvents are critically evaluated. Bioaugmentation of resting-cells previously grown in a fermenter and in-well addition of oxygen and growth substrate appear to be the most promising approaches for aquifer bioremediation. Other solutions involving the sparging of air lead to satisfactory pollutant removals, but must be integrated by the extraction and subsequent treatment of vapors to avoid the dispersion of volatile chlorinated solvents in the atmosphere. Cometabolic bioventing is the only possible approach for the aerobic cometabolic bioremediation of the vadose zone. The examined studies indicate that in situ aerobic cometabolism leads to the biodegradation of a wide range of chlorinated solvents within remediation times that vary between 1 and 17 months. Numerous studies include a simulation of the experimental field data. The modeling of the process attained a high reliability, and represents a crucial tool for the elaboration of field data obtained in pilot tests and for the design of the full-scale systems. Further research is needed to attain higher concentrations of chlorinated solvent degrading microbes and more reliable cost estimates. Lastly, a procedure for the design of full-scale in situ aerobic cometabolic bioremediation processes is proposed. PMID:25306537

  12. In situ aerobic cometabolism of chlorinated solvents: a review.

    Science.gov (United States)

    Frascari, Dario; Zanaroli, Giulio; Danko, Anthony S

    2015-01-01

    The possible approaches for in situ aerobic cometabolism of aquifers and vadose zones contaminated by chlorinated solvents are critically evaluated. Bioaugmentation of resting-cells previously grown in a fermenter and in-well addition of oxygen and growth substrate appear to be the most promising approaches for aquifer bioremediation. Other solutions involving the sparging of air lead to satisfactory pollutant removals, but must be integrated by the extraction and subsequent treatment of vapors to avoid the dispersion of volatile chlorinated solvents in the atmosphere. Cometabolic bioventing is the only possible approach for the aerobic cometabolic bioremediation of the vadose zone. The examined studies indicate that in situ aerobic cometabolism leads to the biodegradation of a wide range of chlorinated solvents within remediation times that vary between 1 and 17 months. Numerous studies include a simulation of the experimental field data. The modeling of the process attained a high reliability, and represents a crucial tool for the elaboration of field data obtained in pilot tests and for the design of the full-scale systems. Further research is needed to attain higher concentrations of chlorinated solvent degrading microbes and more reliable cost estimates. Lastly, a procedure for the design of full-scale in situ aerobic cometabolic bioremediation processes is proposed.

  13. Inhibition of chlorine-induced lung injury by the type 4 phosphodiesterase inhibitor rolipram

    International Nuclear Information System (INIS)

    Chlorine is a highly toxic respiratory irritant that when inhaled causes epithelial cell injury, alveolar-capillary barrier disruption, airway hyperreactivity, inflammation, and pulmonary edema. Chlorine is considered a chemical threat agent, and its release through accidental or intentional means has the potential to result in mass casualties from acute lung injury. The type 4 phosphodiesterase inhibitor rolipram was investigated as a rescue treatment for chlorine-induced lung injury. Rolipram inhibits degradation of the intracellular signaling molecule cyclic AMP. Potential beneficial effects of increased cyclic AMP levels include inhibition of pulmonary edema, inflammation, and airway hyperreactivity. Mice were exposed to chlorine (whole body exposure, 228–270 ppm for 1 h) and were treated with rolipram by intraperitoneal, intranasal, or intramuscular (either aqueous or nanoemulsion formulation) delivery starting 1 h after exposure. Rolipram administered intraperitoneally or intranasally inhibited chlorine-induced pulmonary edema. Minor or no effects were observed on lavage fluid IgM (indicative of plasma protein leakage), KC (Cxcl1, neutrophil chemoattractant), and neutrophils. All routes of administration inhibited chlorine-induced airway hyperreactivity assessed 1 day after exposure. The results of the study suggest that rolipram may be an effective rescue treatment for chlorine-induced lung injury and that both systemic and targeted administration to the respiratory tract were effective routes of delivery. -- Highlights: ► Chlorine causes lung injury when inhaled and is considered a chemical threat agent. ► Rolipram inhibited chlorine-induced pulmonary edema and airway hyperreactivity. ► Post-exposure rolipram treatments by both systemic and local delivery were effective. ► Rolipram shows promise as a rescue treatment for chlorine-induced lung injury.

  14. Chlorine disinfection of dye wastewater: Implications for a commercial azo dye mixture

    Energy Technology Data Exchange (ETDEWEB)

    Vacchi, Francine Inforcato; Albuquerque, Anjaina Fernandes; Vendemiatti, Josiane Aparecida; Morales, Daniel Alexandre [Faculdade de Tecnologia, Universidade Estadual de Campinas, Limeira, SP, 13484-332 (Brazil); Ormond, Alexandra B.; Freeman, Harold S. [Department of Textile Engineering, Chemistry, and Science, North Carolina State University, Raleigh, NC 27695-8301 (United States); Zocolo, Guilherme Juliao; Zanoni, Maria Valnice Boldrin [Departamento de Quimica Analitica, Universidade Estadual Paulista Julio de Mesquita Filho, Instituto de Quimica de Araraquara, Araraquara, SP 14801-970 (Brazil); Umbuzeiro, Gisela, E-mail: giselau@ft.unicamp.br [Faculdade de Tecnologia, Universidade Estadual de Campinas, Limeira, SP, 13484-332 (Brazil)

    2013-01-01

    Azo dyes, the most widely used family of synthetic dyes, are often employed as colorants in areas such as textiles, plastics, foods/drugs/cosmetics, and electronics. Following their use in industrial applications, azo dyes have been found in effluents and various receiving waters. Chemical treatment of effluents containing azo dyes includes disinfection using chlorine, which can generate compounds of varying eco/genotoxicity. Among the widely known commercial azo dyes for synthetic fibers is C.I. Disperse Red 1. While this dye is known to exist as a complex mixture, reports of eco/genotoxicity involve the purified form. Bearing in mind the potential for adverse synergistic effects arising from exposures to chemical mixtures, the aim of the present study was to characterize the components of commercial Disperse Red 1 and its chlorine-mediated decoloration products and to evaluate their ecotoxicity and mutagenicity. In conducting the present study, Disperse Red 1 was treated with chlorine gas, and the solution obtained was analyzed with the aid of LC-ESI-MS/MS to identify the components present, and then evaluated for ecotoxicity and mutagenicity, using Daphnia similis and Salmonella/microsome assays, respectively. The results of this study indicated that chlorination of Disperse Red 1 produced four chlorinated aromatic compounds as the main products and that the degradation products were more ecotoxic than the parent dye. These results suggest that a disinfection process using chlorine should be avoided for effluents containing hydrophobic azo dyes such commercial Disperse Red 1. -- Highlights: Black-Right-Pointing-Pointer Aqueous solutions of Disperse Red 1 were treated with chlorine. Black-Right-Pointing-Pointer The chlorination products of Disperse Red 1 were identified using LC-ESI-MS/MS. Black-Right-Pointing-Pointer Daphnia and Salmonella/microsome were employed for eco/genotoxicity testing. Black-Right-Pointing-Pointer The chlorinated dye was more mutagenic

  15. Kinetics of Chlorination of Benzophenone-3 in the Presence of Bromide and Ammonia.

    Science.gov (United States)

    Abdallah, Pamela; Deborde, Marie; Dossier Berne, Florence; Karpel Vel Leitner, Nathalie

    2015-12-15

    The aim of this study was to assess the impact of chlorination on the degradation of one of the most commonly used UV filters (benzophenone-3 (BP-3)) and the effects of bromide and ammonia on the kinetics of BP-3 elimination. Bromide and ammonia are rapidly converted to bromine and chloramines during chlorination. At first, the rate constants of chlorine, bromine and monochloramine with BP-3 were determined at various pH levels. BP-3 was found to react rapidly with chlorine and bromine, with values of apparent second order rate constants equal to 1.25(±0.14) × 10(3) M(-1)·s(-1) and 4.04(±0.54) × 10(6) M(-1)·s(-1) at pH 8.5 for kChlorine/BP-3 and kBromine/BP-3, respectively, whereas low monochloramine reactivity was observed (kNH2Cl/BP-3 = 0.112 M(-1)·s(-1)). To assess the impact of the inorganic content of water on BP-3 degradation, chlorination experiments with different added concentrations of bromide and/or ammonia were conducted. Under these conditions, BP-3 degradation was found to be enhanced in the presence of bromide due to the formation of bromine, whereas it was inhibited in the presence of ammonia. However, the results obtained were pH dependent. Finally, a kinetic model considering 18 reactions was developed using Copasi to estimate BP-3 degradation during chlorination in the presence of bromide and ammonia.

  16. Field-usable portable analyzer for chlorinated organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Buttner, W.J.; Penrose, W.R.; Stetter, J.R. [Transducer Research, Inc., Naperville, IL (United States)

    1995-10-01

    Transducer Research, Inc. (TRI) has been working with the DOE Morgantown Energy Technology Center to develop a new chemical monitor based on a unique sensor which responds selectively to vapors of chlorinated solvents. We are also developing field applications for the monitor in actual DOE cleanup operations. During the initial phase, prototype instruments were built and field tested. Because of the high degree of selectivity that is obtained, no response was observed with common hydrocarbon organic compounds such as BTX (benzene, toluene, xylene) or POLs (petroleum, oil, lubricants), and in fact, no non-halogen-containing chemical has been identified which induces a measurable response. By the end of the Phase I effort, a finished instrument system was developed and test marketed. This instrument, called the RCL MONITOR, was designed to analyze individual samples or monitor an area with automated repetitive analyses. Vapor levels between 0 and 500 ppm can be determined in 90 s with a lower detection limit of 0.2 ppm using the handportable instrument. In addition to the development of the RCL MONITOR, advanced sampler systems are being developed to: (1) extend the dynamic range of the instrument through autodilution of the vapor and (2) allow chemical analyses to be performed on aqueous samples. When interfaced to the samplers, the RCL MONITOR is capable of measuring chlorinated solvent contamination in the vapor phase up to 5000 ppm and in water and other condensed media from 10 to over 10,000 ppb(wt)--without hydrocarbon and other organic interferences.

  17. The hydrocarbon sphere

    Energy Technology Data Exchange (ETDEWEB)

    Mandev, P.

    1984-01-01

    The hydrocarbon sphere is understood to be the area in which hydrocarbon compounds are available. It is believed that the lower boundary on the hydrocarbon sphere is most probably located at a depth where the predominant temperatures aid in the destruction of hydrocarbons (300 to 400 degrees centigrade). The upper limit on the hydrocarbon sphere obviously occurs at the earth's surface, where hydrocarbons oxidize to H20 and CO2. Within these ranges, the occurrence of the hydrocarbon sphere may vary from the first few hundred meters to 15 kilometers or more. The hydrocarbon sphere is divided into the external (mantle) sphere in which the primary gas, oil and solid hydrocarbon fields are located, and the internal (metamorphic) sphere containing primarily noncommercial accumulations of hydrocarbon gases and solid carbon containing compounds (anthraxilite, shungite, graphite, etc.) based on the nature and scale of hydrocarbon compound concentrations (natural gas, oil, maltha, asphalt, asphaltite, etc.).

  18. Inductively coupled plasma torch efficiency at atmospheric pressure for organo-chlorine liquid waste removal: Chloroform destruction in oxidative conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kamgang-Youbi, Georges, E-mail: kamyougeo@yahoo.fr [French Atomic Commission-CEA, Marcoule-DTCD/SCDV/LPIC, BP 17171, 30207 Bagnols-Sur-Cèze Cedex (France); Department of Inorganic Chemistry, The University of Yaounde I, P.O Box, 812 Yaounde (Cameroon); Poizot, Karine; Lemont, Florent [French Atomic Commission-CEA, Marcoule-DTCD/SCDV/LPIC, BP 17171, 30207 Bagnols-Sur-Cèze Cedex (France)

    2013-01-15

    Highlights: ► Inductively plasma torch is used for the decomposition of organochlorine molecule. ► We examine the impact of liquid water substitution by oxygen gas as oxidant. ► Complete and safe decomposition is achieved with the presence of oxygen. ► The energy efficiency and capabilities of process are better with O{sub 2} than H{sub 2}O. -- Abstract: The performance of a plasma reactor for the degradation of chlorinated hydrocarbon waste is reported. Chloroform was used as a target for a recently patented destruction process based using an inductive plasma torch. Liquid waste was directly injected axially into the argon plasma with a supplied power of ∼4 kW in the presence of oxygen as oxidant and carrier gas. Decomposition was performed at CHCl{sub 3} feed rates up to 400 g h{sup −1} with different oxygen/waste molar ratios, chloroform destruction was obtained with at least 99% efficiency and the energy efficiency reached 100 g kWh{sup −1}. The conversion end products were identified and assayed by online FTIR spectroscopy (CO{sub 2}, HCl and H{sub 2}O) and redox titration (Cl{sub 2}). Considering phosgene as representative of toxic compounds, only very small quantities of toxics were released (<1 g h{sup −1}) even with high waste feed rates. The experimental results were very close to the equilibrium composition predicted by thermodynamic calculations. At the bottom of the reactor, the chlorinated acids were successfully trapped in a scrubber and transformed into mineral salts, hence, only CO{sub 2} and H{sub 2}O have been found in the final off-gases composition.

  19. Transformation of humic acid and halogenated byproduct formation in UV-chlorine processes.

    Science.gov (United States)

    Li, Tong; Jiang, Yan; An, Xiaoqiang; Liu, Huijuan; Hu, Chun; Qu, Jiuhui

    2016-10-01

    The synergistic effect of ultraviolet light (UV) and chlorine on the structural transformation of Humic Acid (HA) and formation of chloro-disinfection byproducts (DBPs) in water were investigated, with chlorination as a reference. The transformation and mineralization of HA were enhanced upon co-exposure to UV and chlorine. Electron spin resonance (ESR) studies revealed that hydroxyl radical (OH) and chlorine radical (Cl) were predominant active species in a pH range from 4 to 7, while Cl dominated at pH 2 and pH higher than 7. The impact of different radicals on the transformation of HA was investigated by UV254, fluorescence and TOC measurements. OH were found to be responsible for the removal of chromophoric groups and mineralization of HA, while Cl mainly reacted with HA and intermediates from HA degradation. Due to the competitive and synergistic reaction of OH and Cl with HA, higher removal of HA and lower formation of chloro-DBPs appeared in UV-chlorine than chlorination, thus the combined UV-chlorine processes should be a promising method for water purification.

  20. Increased formation of halomethanes during chlorination of chloramphenicol in drinking water by UV irradiation, persulfate oxidation, and combined UV/persulfate pre-treatments.

    Science.gov (United States)

    Wenhai, Chu; Tengfei, Chu; Erdeng, Du; Deng, Yang; Yingqing, Guo; Naiyun, Gao

    2016-02-01

    Ultraviolet/persulfate (UV/PS) has been widely used to generate sulfate radicals for degradation of water organic pollutants in previous studies. However, its impacts on disinfection byproduct formation during post-chlorination of degraded compounds is unclear. The objective of this study was to evaluate the impacts of UV irradiation, PS oxidation, and the combined UV/PS advanced oxidation process (AOP) pre-treatments on halomethane formation during the following chlorination of chloramphenicol (CAP), a model antibiotic commonly found in wastewater-impacted water. Results showed that CAP could be transformed to more trichloromethane (TCM) than monochloromethane (MCM) and dichloromethane (DCM) in the presence of excess chlorine. UV photolysis, PS oxidation and UV/PS AOP all directly decomposed CAP to produce halomethanes (HMs) before post-chlorination. Moreover, UV and UV/PS pre-treatments both enhanced the formation of all the HMs in the subsequent chlorination. PS pre-oxidation decreased the TCM formation during post-chlorination, but increased the yields of MCM, DCM and total HMs. UV pre-irradiation significantly increased the bromide utilization of HMs, whereas UV/PS pre-oxidation decreased the bromine incorporation and utilization of HMs from the chlorination of CAP in a low-bromide water. UV irradiation, PS oxidation, and UV/PS AOP can inactivate pathogens and degrade organic pollutants, but this benefit should be weighed against a potential risk of the increased halomethane formation from degraded organic pollutants with and without post-chlorination.

  1. Petroleum Hydrocarbons, Chlorinated Hydrocarbons, and Metal in Soils and Sediments of Quivira National Wildlife Refuge, 1989

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Numerous oil production facilities were in place when Quivira NWR was purchased, and oil production has continued and some new production facilities have been...

  2. Effects of ozone, chlorine dioxide, chlorine, and monochloramine on Cryptosporidium parvum oocyst viability.

    OpenAIRE

    Korich, D G; Mead, J R; Madore, M S; Sinclair, N. A.; Sterling, C R

    1990-01-01

    Purified Cryptosporidium parvum oocysts were exposed to ozone, chlorine dioxide, chlorine, and monochloramine. Excystation and mouse infectivity were comparatively evaluated to assess oocyst viability. Ozone and chlorine dioxide more effectively inactivated oocysts than chlorine and monochloramine did. Greater than 90% inactivation as measured by infectivity was achieved by treating oocysts with 1 ppm of ozone (1 mg/liter) for 5 min. Exposure to 1.3 ppm of chlorine dioxide yielded 90% inactiv...

  3. Purex diluent degradation

    Energy Technology Data Exchange (ETDEWEB)

    Tallent, O.K.; Mailen, J.C.; Pannell, K.D.

    1984-02-01

    The chemical degradation of normal paraffin hydrocarbon (NPH) diluents both in the pure state and mixed with 30% tributyl phosphate (TBP) was investigated in a series of experiments. The results show that degradation of NPH in the TBP-NPH-HNO/sub 3/ system is consistent with the active chemical agent being a radical-like nitrogen dioxide (NO/sub 2/) molecule, not HNO/sub 3/ as such. Spectrophotometric, gas chromatographic, mass spectrographic, and titrimetric methods were used to identify the degradation products, which included alkane nitro and nitrate compounds, alcohols, unsaturated alcohols, nitro alcohols, nitro alkenes, ketones, and carboxylic acids. The degradation rate was found to increase with increases in the HNO/sub 3/ concentration and the temperature. The rate was decreased by argon sparging to remove NO/sub 2/ and by the addition of butanol, which probably acts as a NO/sub 2/ scavenger. 13 references, 11 figures.

  4. Purex diluent degradation

    International Nuclear Information System (INIS)

    The chemical degradation of normal paraffin hydrocarbon (NPH) diluents both in the pure state and mixed with 30% tributyl phosphate (TBP) was investigated in a series of experiments. The results show that degradation of NPH in the TBP-NPH-HNO3 system is consistent with the active chemical agent being a radical-like nitrogen dioxide (NO2) molecule, not HNO3 as such. Spectrophotometric, gas chromatographic, mass spectrographic, and titrimetric methods were used to identify the degradation products, which included alkane nitro and nitrate compounds, alcohols, unsaturated alcohols, nitro alcohols, nitro alkenes, ketones, and carboxylic acids. The degradation rate was found to increase with increases in the HNO3 concentration and the temperature. The rate was decreased by argon sparging to remove NO2 and by the addition of butanol, which probably acts as a NO2 scavenger. 13 references, 11 figures

  5. Biological degradation of petroleum hydrocarbons in the Northsea with special reference to component difficult to biodegrade and useful as key compounds for marine environmental monitoring by chemical analysis. Biologischer Abbau von Erdoelkohlenwasserstoffen in der Nordsee unter besonderer Beruecksichtigung von schwer abbaubaren Komponenten, die als Leitsubstanzen fuer die chemisch analytische Ueberwachung der Meeresumwelt dienen sollen

    Energy Technology Data Exchange (ETDEWEB)

    Bruns, K.; Gunkel, W. (Biologische Anstalt Helgoland (Germany, F.R.). Meeresstation); Dahlmann, G.; Theobald, N. (Deutsches Hydrographisches Inst., Hamburg (Germany, F.R.). Lab. Suelldorf)

    1989-01-01

    Supplemented degradation tests of petroleum by marine bacteria in batch culture were analysed by gas chromatography and combined gas chromatography and mass spectroscopy. The results show a variety of effects produced by the different nutrient salts concentrations and combinations with trace elements. The known supplementation of microbial oil degradation by nitrogen and phosphorus is greatly enhanced in its effectiveness by the addition of trace elements. Even those oil components which are known to be resistant to biodegradation, will be attacked when incubated with low concentrations of nitrogen and phosphorus (0.01 NP or P 4xN) and trace elements; pyrene and methyl dibenzothiophenes, for instance, were reduced by 40 to 50% after 6 week incubation. An optimal composition resulting in optimal biodegradation in any of the oils studied, was not found. The findings suggest that the biodegradation of specific petroleum hydrocarbons is determined by the composition and concentration of the supplementation used. (orig.).

  6. Removal of Chlorinated Chemicals in H2 Feedstock Using Modified Activated Carbon

    Directory of Open Access Journals (Sweden)

    Prapaporn Luekittisup

    2015-01-01

    Full Text Available Activated carbon (GAC was impregnated by sodium and used as adsorbent to remove chlorinated hydrocarbon (CHC gases contaminated in H2 feedstock. The adsorption was carried out in a continuous packed-bed column under the weight hourly space velocity range of 0.8–1.0 hr−1. The adsorption capacity was evaluated via the breakthrough curves. This modified GAC potentially adsorbed HCl and VCM of 0.0681 gHCl/gadsorbent and 0.0026 gVCM/gadsorbent, respectively. It showed higher adsorption capacity than SiO2 and Al2O3 balls for both organic and inorganic CHCs removal. In addition, the kinetic adsorption of chlorinated hydrocarbons on modified GAC fit well with Yoon-Nelson model.

  7. Ultrafast measurements of chlorine dioxide photochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Ludowise, P.D.

    1997-08-01

    Time-resolved mass spectrometry and time-resolved photoelectron spectroscopy are used to study the ultrafast photodissociation dynamics of chlorine dioxide, an important constituent in stratospheric ozone depletion. Chapter 1 introduces these pump/probe techniques, in which a femtosecond pump pulse excites a molecule to a dissociative state. At a later time, a second femtosecond probe pulse ionizes the molecule. The resulting mass and photoelectron spectra are acquired as a function of the delay between the pump and probe pulses, which follows the evolution of the molecule on the excited state. A comparison to other techniques used to study reaction dynamics is discussed. Chapter 2 includes a detailed description of the design and construction of the experimental apparatus, which consists of a femtosecond laser system, a molecular beam time-of-flight spectrometer, and a data acquisition system. The time-of-flight spectrometer is specifically designed to have a short flight distance to maximize the photoelectron collection efficiency without degrading the resolution, which is limited by the bandwidth of the femtosecond laser system. Typical performance of the apparatus is demonstrated in a study of the time-resolved photoelectron spectroscopy of nitric oxide. The results of the time-resolved mass spectrometry experiments of chlorine dioxide are presented in Chapter 3. Upon excitation to the A {sup 2}A{sub 2} state near 3.2 eV, the molecule dissociates through an indirect two-step mechanism. The direct dissociation channel has been predicted to be open, but is not observed. A quantum beat is observed in the OClO{sup +} species, which is described as a vibrational coherence of the optically prepared A {sup 2}A{sub 2} state. Chapter 4 presents the results of the time-resolved photoelectron experiments of chlorine dioxide. At short delay time, the quantum beat of the OClO{sup +} species is observed in the X {sup 1}A{sub 1} state of the ion. At infinite delay, the signal

  8. Raman characteristics of hydrocarbon and hydrocarbon inclusions

    Institute of Scientific and Technical Information of China (English)

    ZHANG Nai; TIAN ZuoJi; LENG YingYing; WANG HuiTong; SONG FuQing; MENG JianHua

    2007-01-01

    The Raman spectrograms of hydrocarbon standard samples show that: (1) the Raman spectrogram of normal paraffin has very strong peaks of methyl and methylene (from 2700 cm-1 to 2970 cm-1); (2)branch methyl has the particular peak of 748 cm-1±; (3) six cyclic has the particular peak of 804 cm-1±; (4)phenyl has two particular peaks of 988 cm-1± and 3058 cm-1± and the 988 cm-1± peak is stronger than the 3058 cm-1± peak; and (5) hexene has three alkenyl spectrum peaks of 1294 cm-1±, 1635 cm-1± and 2996 cm-1±, with the 1635 cm-1± peak being the strongest, showing that the number of carbon in hydrocarbon does not affect its Raman spectrogram, and the hydrocarbon molecular structure and base groups affect its Raman spectrogram, the same hydrocarbons (such as normal paraffin) have the same Raman spectrogram; the types (such as CH4, C2H6, C3H8) and the content of hydrocarbon in oil inclusions are not estimated by their characteristic Raman peaks. According to the Raman spectrograms of hydrocarbon compositions, the Raman spectrogram of hydrocarbon inclusion can be divided into five types: saturated hydrocarbon Raman spectrogram, fluoresce Raman spectrogram, saturated hydrocarbon bitumen Raman spectrogram, bitumen Raman spectrogram, and ethane Raman spectrogram.And according to the characteristics of Raman spectrogram, hydrocarbon inclusions can be divided into five types: saturated hydrocarbon inclusion, less saturated hydrocarbon (oil or gas) inclusion,saturated hydrocarbon bitumen inclusion, bitumen inclusion, and methane water inclusion.

  9. Raman characteristics of hydrocarbon and hydrocarbon inclusions

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The Raman spectrograms of hydrocarbon standard samples show that: (1) the Raman spectrogram of normal paraffin has very strong peaks of methyl and methylene (from 2700 cm-1 to 2970 cm-1); (2) branch methyl has the particular peak of 748 cm-1±; (3) six cyclic has the particular peak of 804 cm-1±; (4) phenyl has two particular peaks of 988 cm-1± and 3058 cm-1± and the 988 cm-1± peak is stronger than the 3058 cm-1± peak; and (5) hexene has three alkenyl spectrum peaks of 1294 cm-1±, 1635 cm-1± and 2996 cm-1±, with the 1635 cm-1± peak being the strongest, showing that the number of carbon in hy-drocarbon does not affect its Raman spectrogram, and the hydrocarbon molecular structure and base groups affect its Raman spectrogram, the same hydrocarbons (such as normal paraffin) have the same Raman spectrogram; the types (such as CH4, C2H6, C3H8) and the content of hydrocarbon in oil inclu-sions are not estimated by their characteristic Raman peaks. According to the Raman spectrograms of hydrocarbon compositions, the Raman spectrogram of hydrocarbon inclusion can be divided into five types: saturated hydrocarbon Raman spectrogram, fluoresce Raman spectrogram, saturated hydro-carbon bitumen Raman spectrogram, bitumen Raman spectrogram, and ethane Raman spectrogram. And according to the characteristics of Raman spectrogram, hydrocarbon inclusions can be divided into five types: saturated hydrocarbon inclusion, less saturated hydrocarbon (oil or gas) inclusion, saturated hydrocarbon bitumen inclusion, bitumen inclusion, and methane water inclusion.

  10. Effects of chlorine content and position of chlorinated phenols on their oxidation kinetics by potassium permanganate

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Chlorine content and position of chlorinated phenols have many significant effects on the reactivity of oxido-reduction. The effects of chlorine content and position of chlorinated phenols on their oxidation kinetics by potassium permanganate were evaluated through different kinetics studies. Since chlorine was an electron withdrawing atom, the substitution of chlorine on the aromatic ring decreased the oxidation rate constant by σ-electron withdrawing conductive effect; at the same time, the substitution of chlorine at ortho or para position on the aromatic ring increased the oxidation rate constant by π-electron donating conjugative effect, and the conjugative effect could counteract the negative impact of the conductive effect to some extent. On the other hand, the substitution of chlorine at ortho position on the aromatic ring decreased the oxidation rate constant by steric hindrance effect. The oxidation rate constants of phenol and chlorinated phenols studied decreased as follow order: 4-chlorophenol>2,4-dichlorophenol>phenol>2,6-dichlorophenol.

  11. Assessment of the advanced oxidation process , photo-fenton, on the degradation of polyaromatics hydrocarbons contained on the aqueous part of oil in superficial sea water; Avaliacao do processo oxidativo avancado, foto-fenton, na degradacao dos hidrocarbonetos poliaromaticos contidos na fracao soluvel do petroleo em agua superficial salina

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Rita C.R. da; Silva, Valdinete L. da; Paim, Ana Paula Silveira [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil); Rocha, Otidene R.S. da; Duarte, Marcia M.L. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

    2008-07-01

    The pollution for oil has been one of the main ambient problems of the last decades. It exists an increasing interest in the study of the destination and forms of disappearance of the constituent hydrocarbons of the oil aiming at the development of more efficient methods of removal of the same ones of the environment. With objective to evaluate the process photo-fenton, in the treatment of the contaminated saline superficial water with polyaromatics hydrocarbons (HPAs) contained in the crude oil, mounted an experiment using reactor of black light, the hydrogen peroxide as oxidant agent. After the degradation the samples had been submitted to the analysis in the GC-MS, and for the 31 specters it was observed that the best ones resulted had been gotten when mmol of H{sub 2}O{sub 2} in 8 was used h of exposition to the irradiation and with pH of the equal system the 4. In the specter of this assay the characteristic peaks of the HPAs disappear completely or appear in a lowly intensities, proving that it had rupture of aromatical rings consequently and the degradation of the same ones or that its concentrations meet below of the limit of detention of the equipment. Soon, with the gotten results it can be concluded that the POAs, in special the process photo-fenton, is presented as a viable alternative in the contaminated saline superficial water treatment with the HPAs contained in the rude oil. (author)

  12. Durability of Selected Membrane Materials when Exposed to Chlorine Gas

    Energy Technology Data Exchange (ETDEWEB)

    Eikeland, Marianne Soerflaten

    2001-03-01

    This thesis is focusing on the durability of selected membrane materials when exposed to chlorine gas in the temperature range 30-100{sup o}C. Studies of the changes of membrane separation properties and the mechanisms promoting these changes have been studied. The selected membrane materials were poly(dimethylsioxane) (PDMS), Fluorel, fluorosilicone, and blends of PDMS and Fluorel. The thesis is organised in seven chapters. The first chapter gives an introduction to the background of the work. The second chapter presents the theory for gas separation using dense rubbery membranes. The properties of the selected membrane materials are presented in chapter three. The fourth chapter describes degradation mechanisms for polymeric materials in general and for the selected membrane materials in particular. Presentation of the experimental work is given in chapter five, while the results with discussions are presented in chapter six. The conclusions and recommendations for further studies are given in chapter seven. Five appendixes are attached: Appendix A describes the calculations of permeability and solubility coefficients and the accuracy of the experimental measurements. Appendix B summarises the measured values in tables and Appendix C describes the analytical methods. Appendix D gives the properties of the gases used in the experiments. Appendix E is the article ''Durability of Poly(dimethylsiloxane) when Exposed to Chlorine Gas'', submitted to the Journal of Applied Polymer Science. Highly crosslinked PDMS was found to have an initial high permeability for chlorine gas and a high Cl{sub 2}/O{sub 2} selectivity. However when exposed to chlorine gas the permeability decreased significantly. Crosslinking of the PDMS polymer chain and chlorination of the polymer gave a denser polymer structure and thus lower permeability. Fluorel showed very low permeabilities and selectivities for the gases in question and was thus not interesting for this

  13. Chlorine signal attenuation in concrete.

    Science.gov (United States)

    Naqvi, A A; Maslehuddin, M; ur-Rehman, Khateeb; Al-Amoudi, O S B

    2015-11-01

    The intensity of prompt gamma-ray was measured at various depths from chlorine-contaminated silica fume (SF) concrete slab concrete specimens using portable neutron generator-based prompt gamma-ray setup. The intensity of 6.11MeV chloride gamma-rays was measured from the chloride contaminated slab at distance of 15.25, 20.25, 25.25, 30.25 and 35.25cm from neutron target in a SF cement concrete slab specimens. Due to attenuation of thermal neutron flux and emitted gamma-ray intensity in SF cement concrete at various depths, the measured intensity of chlorine gamma-rays decreases non-linearly with increasing depth in concrete. A good agreement was noted between the experimental results and the results of Monte Carlo simulation. This study has provided useful experimental data for evaluating the chloride contamination in the SF concrete utilizing gamma-ray attenuation method.

  14. Comparative genome analysis of Pseudomonas knackmussii B13, the first bacterium known to degrade chloroaromatic compounds.

    Science.gov (United States)

    Miyazaki, Ryo; Bertelli, Claire; Benaglio, Paola; Canton, Jonas; De Coi, Nicoló; Gharib, Walid H; Gjoksi, Bebeka; Goesmann, Alexander; Greub, Gilbert; Harshman, Keith; Linke, Burkhard; Mikulic, Josip; Mueller, Linda; Nicolas, Damien; Robinson-Rechavi, Marc; Rivolta, Carlo; Roggo, Clémence; Roy, Shantanu; Sentchilo, Vladimir; Siebenthal, Alexandra Von; Falquet, Laurent; van der Meer, Jan Roelof

    2015-01-01

    Pseudomonas knackmussii B13 was the first strain to be isolated in 1974 that could degrade chlorinated aromatic hydrocarbons. This discovery was the prologue for subsequent characterization of numerous bacterial metabolic pathways, for genetic and biochemical studies, and which spurred ideas for pollutant bioremediation. In this study, we determined the complete genome sequence of B13 using next generation sequencing technologies and optical mapping. Genome annotation indicated that B13 has a variety of metabolic pathways for degrading monoaromatic hydrocarbons including chlorobenzoate, aminophenol, anthranilate and hydroxyquinol, but not polyaromatic compounds. Comparative genome analysis revealed that B13 is closest to Pseudomonas denitrificans and Pseudomonas aeruginosa. The B13 genome contains at least eight genomic islands [prophages and integrative conjugative elements (ICEs)], which were absent in closely related pseudomonads. We confirm that two ICEs are identical copies of the 103 kb self-transmissible element ICEclc that carries the genes for chlorocatechol metabolism. Comparison of ICEclc showed that it is composed of a variable and a 'core' region, which is very conserved among proteobacterial genomes, suggesting a widely distributed family of so far uncharacterized ICE. Resequencing of two spontaneous B13 mutants revealed a number of single nucleotide substitutions, as well as excision of a large 220 kb region and a prophage that drastically change the host metabolic capacity and survivability. PMID:24803113

  15. Oxidation of pharmaceuticals by chlorine dioxide in biologically treated wastewater

    OpenAIRE

    Hey, G.; Grabic, R.; Ledin, A.; la Cour Jansen, J; Andersen, H R

    2012-01-01

    Biologically treated wastewater spiked with a mixture of 56 active pharmaceutical ingredients (APIs) was treated with 0–20mg/L chlorine dioxide (ClO2) solution in laboratory-scale experiments. Wastewater effluents were collected from two wastewater treatment plants in Sweden, one with extended nitrogen removal (low COD) and one without (high COD). About one third of the tested APIs resisted degradation even at the highest ClO2 dose (20mg/L), while others were reduced by more than 90% at the l...

  16. The effect of chlorine and combined chlorine/UV treatment on coliphages in drinking water disinfection.

    Science.gov (United States)

    Zyara, Alyaa M; Torvinen, Eila; Veijalainen, Anna-Maria; Heinonen-Tanski, Helvi

    2016-08-01

    Chlorine disinfection is a globally used method to ensure the safety of drinking water. However, it has not always been successful against viruses and, therefore, it is important to find new methods to disinfect water. Seventeen different coliphages were isolated from the treated municipal wastewater. These coliphages and MS2 were treated with different dosages of chlorine in drinking water, and a combined chlorine/ultraviolet irradiation treatment for the chlorine-resistant coliphages. Chlorine disinfection with 0.3-0.5 mg/L total chlorine (free Cl-dosage 0.12-0.21 mg/L) for 10 min achieved 2.5-5.7 Log10-reductions for 11 sensitive coliphages. The six most resistant coliphages showed no reduction with these chlorine concentrations. MS2 was intermediate in chlorine resistance, and thus it is not a good indicator for viruses in chlorine disinfection. In the combined treatment total chlorine of 0.05-0.25 mg/L (free Cl-dosage 0.02-0.08 mg/L) and ultraviolet irradiation (14-22 mWs/cm(2)) were more effective than chlorine alone, and 3-5 Log10-reductions were achieved for the chlorine-resistant strains. The chlorination efficiency could be increased by higher dosages and longer contact times, but this could increase the formation of disinfection by-products. Therefore, the combination treatment is a recommended disinfection method.

  17. Two-phase ozonation of chlorinated organics

    International Nuclear Information System (INIS)

    In the last few years the amount of research being conducted in the field of single-phase ozonation has grown extensively. However, traditional aqueous-phase ozonation systems are limited by a lack of selective oxidation potential, low ozone solubility in water, and slow intermediate decomposition rates. Furthermore, ozone may decompose before it can be utilized for pollutant destruction since ozone can be highly unstable in aqueous solutions. Naturally occurring compounds such as NaHCO3 also affect ozone reactions by inhibiting the formation of OH-free radicals. To compensate for these factors, excess ozone is typically supplied to a reactor. Since ozone generation requires considerable electric power consumption (16 - 24 kWh/kg of O3), attempts to enhance the ozone utilization rate and stability should lead to more efficient application of this process to hazardous waste treatment. To improve the process, ozonation may be more efficiently carried out in a two-phase system consisting of an inert solvent (saturated with O3) contacted with an aqueous phase containing pollutants. The non-aqueous phase must meet the following criteria: (1) non-toxic, (2) very low vapor pressure, (3) high density (for ease of separation), (4) complete insolubility in water, (5) reusability, (6) selective pollutant extractability, (7) high oxidant solubility, and (8) extended O3 stability. Previously published studies (1) have indicated that a number of fluorinated hydrocarbon compounds fit these criteria. For this project, FC40 (a product of 3M Co.) was chosen due to its low vapor pressure (3 mm Hg) and high specific gravity (1.9). The primary advantages of the FC40 solvent are that it is non-toxic, reusable, has an ozone solubility 10 times that of water, and that 85 % of the ozone remains in the solvent even after 2 hours. This novel two-phase process has been utilized to study the rapid destruction of organic chlorine compounds and organic mixtures

  18. Fracturing graphene by chlorination: a theoretical viewpoint

    OpenAIRE

    Ijäs, M.; Havu, P.; Harju, A.

    2012-01-01

    Motivated by the recent photochlorination experiment [B. Li et al., ACS Nano 5, 5957 (2011)], we study theoretically the interaction of chlorine with graphene. In previous theoretical studies, covalent binding between chlorine and carbon atoms has been elusive upon adsorption to the graphene basal plane. Interestingly, in their recent experiment, Li et al. interpreted their data in terms of chemical bonding of chlorine on top of the graphene plane, associated with a change from sp2 to sp3 in ...

  19. Kinetics of the oxidation of cylindrospermopsin and anatoxin-a with chlorine, monochloramine and permanganate.

    Science.gov (United States)

    Rodríguez, Eva; Sordo, Ana; Metcalf, James S; Acero, Juan L

    2007-05-01

    Cyanobacteria produce toxins that may contaminate drinking water sources. Among others, the presence of the alkaloid toxins cylindrospermopsin (CYN) and anatoxin-a (ANTX) constitutes a considerable threat to human health due to the acute and chronic toxicity of these compounds. In the present study, not previously reported second-order rate constants for the reactions of CYN and ANTX with chlorine and monochloramine and of CYN with potassium permanganate were determined and the influence of pH and temperature was established for the most reactive cases. It was found that the reactivity of CYN with chlorine presents a maximum at pH 7 (rate constant of 1265 M(-1)s(-1)). However, the oxidation of CYN with chloramine and permanganate are rather slow processes, with rate constants <1 M(-1)s(-1). The first chlorination product of CYN was found to be 5-chloro-CYN (5-Cl-CYN), which reacts with chlorine 10-20 times slower than the parent compound. The reactivity of ANTX with chlorine and chloramines is also very low (k<1M(-1)s(-1)). The elimination of CYN and ANTX in surface water was also investigated. A chlorine dose of 1.5 mg l(-1) was enough to oxidize CYN almost completely. However, 3 mg l(-1) of chlorine was able to remove only 8% of ANTX, leading to a total formation of trihalomethanes (TTHM) at a concentration of 150 microg l(-1). Therefore, chlorination is a feasible option for CYN degradation during oxidation and disinfection processes but not for ANTX removal. The permanganate dose required for CYN oxidation is very high and not applicable in waterworks.

  20. Potassium chloride production by microcline chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Orosco, Pablo, E-mail: porosco@unsl.edu.ar [Instituto de Investigaciones en Tecnología Química (INTEQUI), Chacabuco y Pedernera, San Luis (Argentina); Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Chacabuco y Pedernera, San Luis (Argentina); Ruiz, María del Carmen [Instituto de Investigaciones en Tecnología Química (INTEQUI), Chacabuco y Pedernera, San Luis (Argentina)

    2015-08-10

    Highlights: • Use of chlorination for the KCl production. • The reagents used were microcline, hydromagnesite and chlorine. • Isothermal and non-isothermal assays were performed in Cl{sub 2}–N{sub 2} mixture. • The chlorination generated KCl at 700 °C. • The chlorination products promote KCl formation. - Abstract: The potassium chloride is one of the most important fertilizers used in agriculture. The current demand of this salt makes interesting the study of potassium chloride production from unconventional potassium resources. In this work the potassium chloride production by chlorination of microcline was investigated. The starting reagents were microcline, hydromagnesite and chlorine. Non-isothermal and isothermal chlorination assays were carried out in a thermogravimetric device adapted to work in corrosive atmospheres. The temperature effect on potassium extraction and the phase transformations produced during chlorination of microcline were studied. The reagents and reaction products were analyzed by X-ray fluorescence (XRF) and X-ray diffraction (XRD). The experimental results indicated that by chlorination of microcline an important extraction of potassium in the temperature range from 800 to 900 °C was produced. Moreover, at 800 °C the forsterite, enstatite and magnesium aluminate spinel phases were generated.

  1. The chlorination of cyclopentanone and cyclohexanone

    NARCIS (Netherlands)

    Maatman, Hendrik

    1980-01-01

    In this thesis the results of an investigation of the chlorination of cyclopentanone and cyclohexanone in the solvent carbontetrachloride and catalyzed by hydrogen chloride are described. ... Zie: Summary

  2. High resolution spectrophotometry for identification of chlorine dioxide in concentrated chlorine solutions.

    Science.gov (United States)

    Gauw, R D; Emmert, G L; Bubnis, B; Gordon, G

    1999-12-01

    Electrolyzed salt brine generators hold great promise for water disinfection in small communities and remote locations. Electrolysis cell liquors have been reported to contain chlorine, chlorine dioxide and ozone. High resolution spectrophotometry was used to observe the presence (or absence) of a unique spectral absorbance pattern present in solutions containing 1-2 mg/l chlorine dioxide. PMID:18967802

  3. Use of chlorination, ozonization and GAC adsorption to eliminate triazine pesticides in water supplies

    International Nuclear Information System (INIS)

    This study is focused on the research made between Facsa and Universidad de Zaragoza (Spain) related to the oxidation techniques application by chlorination and ozonization, and their combination with granular activated carbon (GAC) adsorption of mineral origin, in order to control triazine pesticides in water supplies. Experiments are carried out is a pilot plant. Although the chlorination or ozonization can partially degrade pesticides under study (atrazine, simazine, terbutilazine and bromacil), their passing through an adsorption column with GAC mineral, achieves their total removal when their initial concentrations are about 500 ng/l. These concentrations are obtained by fortification of studied sample. (Author) 9 refs

  4. Formation of chlorinated lipids post-chlorine gas exposure.

    Science.gov (United States)

    Ford, David A; Honavar, Jaideep; Albert, Carolyn J; Duerr, Mark A; Oh, Joo Yeun; Doran, Stephen; Matalon, Sadis; Patel, Rakesh P

    2016-08-01

    Exposure to chlorine (Cl2) gas can occur during accidents and intentional release scenarios. However, biomarkers that specifically indicate Cl2 exposure and Cl2-derived products that mediate postexposure toxicity remain unclear. We hypothesized that chlorinated lipids (Cl-lipids) formed by direct reactions between Cl2 gas and plasmalogens serve as both biomarkers and mediators of post-Cl2 gas exposure toxicities. The 2-chloropalmitaldehyde (2-Cl-Pald), 2-chlorostearaldehyde (2-Cl-Sald), and their oxidized products, free- and esterified 2-chloropalmitic acid (2-Cl-PA) and 2-chlorostearic acid were detected in the lungs and plasma of mouse and rat models of Cl2 gas exposure. Levels of Cl-lipids were highest immediately post-Cl2 gas exposure, and then declined over 72 h with levels remaining 20- to 30-fold higher at 24 h compared with baseline. Glutathione adducts of 2-Cl-Pald and 2-Cl-Sald also increased with levels peaking at 4 h in plasma. Notably, 3-chlorotyrosine also increased after Cl2 gas exposure, but returned to baseline within 24 h. Intranasal administration of 2-Cl-PA or 2-Cl-Pald at doses similar to those formed in the lung after Cl2 gas exposure led to increased distal lung permeability and inflammation and systemic endothelial dysfunction characterized by loss of eNOS-dependent vasodilation. These data suggest that Cl-lipids could serve as biomarkers and mediators for Cl2 gas exposure and toxicity. PMID:27324796

  5. Behavior of chlorine in lake water

    International Nuclear Information System (INIS)

    Water from monsoon fed Sagre lake is being used as a source of raw water for Tarapur Atomic Power Station (TAPS--1 and 2). The raw water from the lake is initially pumped to Sagre water treatment plant (SWTP) operated by Maharashtra Industrial Development Corporation (MIDC) from where, the processed water is sent to cater the needs of both the units of TAPS-1 and 2, townships of TAPS and MIDC, and the nearby villages. At the SWTP the raw water is treated with alum to remove the turbidity, filtered and chlorinated using bleaching powder. All these years the raw water is chlorinated in such a way whereby a residual chlorine level of 0.5-1.0 mg/l, is maintained at the outlet of water treatment plant. The adequacy of the current chlorination practice was investigated, at the request of the NPC-500 MWe group during 1990, so that the future requirements of raw water for TAPP-3 and 4, can be met from the expanded SWTP. In this connection experiments on chlorine dose -- residual chlorine relationship and the decay pattern of chlorine with time was carried out in the lake water (with low value of total dissolved solids and total hardness 3 sample at the site. The total bacterial count in the raw water observed to be 107 counts/ml originally came down to 103 counts/ml at the end of one-hour exposure time to chlorine. It was found that the chlorine demand of the water was around 6 mg/l. In addition Jar test to evaluate the aluminum dose was also carried out. Based on these experiments a chlorine dose of 6 mg/l for one hour contact time was arrived at. The experimental findings were in agreement with the current chlorination practices. (author)

  6. Oxidation of pharmaceuticals by chlorine dioxide in biologically treated wastewater

    DEFF Research Database (Denmark)

    Hey, G.; Grabic, R.; Ledin, A.;

    2012-01-01

    nitrogen removal (low COD) and one without (high COD). About one third of the tested APIs resisted degradation even at the highest ClO2 dose (20mg/L), while others were reduced by more than 90% at the lowest ClO2 level (0.5mg/L). In the low COD effluent, more than half of the APIs were oxidized at 5mg/L Cl......O2, while in high COD effluent a significant increase in API oxidation was observed after treatment with 8mg/L ClO2. This study illustrates the successful degradation of several APIs during treatment of wastewater effluents with chlorine dioxide....

  7. Process for producing hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Doi, K.; Komatsu, A.; Moroe, M.; Moroe, T.

    1980-07-22

    A process is described for producing a hydrocarbon product consisting essentially of hydrocarbons having about 10 to 50 carbon atoms with 60% or more of said product consisting of hydrocarbons containing 25 to 32 carbon atoms which comprises subjecting a synthetic polyisoprene rubber having 92 to 97% cis-type double bods to a thermally destructive distillation at about 300 to 400/sup 0/ C for about 30 minutes under a reduced pressure of about 0.1 to 5 mm. Hg to obtain said hydrocarbon product consisting essentially of hydrocarbons having about 10 to 50 carbon atoms with 60% or more of said product consisting of hydrocarbons containing 25 to 35 carbon atoms, said hydrocarbon product not having a bad odor and containing scarcely any resinous material.

  8. Chlorine dioxide and by-products in water distribution systems

    OpenAIRE

    Ferreira, Francisco Cardoso

    1991-01-01

    Chlorine dioxide is used as both a pre-oxidant and/or a post-disinfectant in several water treatment plants in the United States. Chlorine dioxide is associated with its byproducts chlorite and chlorate. Chlorine dioxide, chlorine, chlori te and chlorate were sampled in four distribution systems where chlorine dioxide is used for disinfection purposes: Charleston, WV, Columbus, GA, New Castle, PA, and Skagit, WA. The fate of chlorine dioxide and its by-products in dist...

  9. Inactivation of simian rotavirus SA11 by chlorine, chlorine dioxide, and monochloramine.

    OpenAIRE

    Berman, D.; Hoff, J C

    1984-01-01

    The kinetics of inactivation of simian rotavirus SA11 by chlorine, chlorine dioxide, and monochloramine were studied at 5 degrees C with a purified preparation of single virions and a preparation of cell-associated virions. Inactivation of the virus preparations with chlorine and chlorine dioxide was studied at pH 6 and 10. The monochloramine studies were done at pH 8. With 0.5 mg of chlorine per liter at pH 6, more than 4 logs (99.99%) of the single virions were inactivated in less than 15 s...

  10. 21 CFR 173.300 - Chlorine dioxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Chlorine dioxide. 173.300 Section 173.300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SECONDARY DIRECT FOOD ADDITIVES PERMITTED IN FOOD FOR HUMAN CONSUMPTION Specific Usage Additives § 173.300 Chlorine...

  11. Elements from chlorine to calcium nuclear reactions

    CERN Document Server

    Kunz, Wunibald

    1968-01-01

    Nuclear Tables: Part II Nuclear Reactions, Volume 3: The Elements from Chlorine to Calcium contains tabulations of the nuclear reaction values of elements chlorine, argon, potassium, and calcium. These tabulations provide the calculated Q-values of the elements and their isotopes. This book will be of value to general chemistry researchers.

  12. APLICACIÓN DE SALES DE TETRAZOLIO DE NUEVA GENERACIÓN (XTT PARA LA ESTIMACIÓN DE LA DENSIDAD DE MICROORGANISMOS DEGRADADORES DE HIDROCARBUROS EMPLEANDO LA TÉCNICA DEL NÚMERO MÁS PROBABLE Application of the New Generation Tetrazolium Salt (XTT for the Enumeration of Hydrocarbon Degrading Microorganisms Using the Most Probable Number Method

    Directory of Open Access Journals (Sweden)

    VICTORIA EUGENIA VALLEJO

    Full Text Available El presente estudio evaluó el desempeño de dos sales de tetrazolio, una tradicional: INT y una de nueva generación: XTT, para estimar la densidad de microorganismos degradadores de hidrocarburos (HCs en suelos empleando la técnica del Número Más Probable (NMP. Se analizaron 96 muestras de suelo provenientes de la Ecorregión Cafetera de Colombia. Los microorganismos fueron recuperados en agar mínimo de sales en atmósfera saturada de HCs y la capacidad degradadora fue confirmada por repiques sucesivos utilizando diesel como fuente de carbono. No se observaron diferencias significativas en los recuentos de microorganismos degradadores obtenidos con las dos sales (t de Student, p The objective of this study was to evaluate the performance of two tetrazolium indicators: a traditional one: INT and a new generation one: XTT, for the estimation of hydrocarbon (HC degrading microorganism s density using the Most Probable Number Technique (MPN. Ninety six composite soil samples were taken and analyzed from Ecorregión Cafetera Colombiana. Degrading microorganisms were recovered in minimum salt medium with saturated HC atmosphere. Degrading HC capacity of the microorganisms was confirmed by successive subcultures in the same medium using diesel as only carbon source. Counts obtained with the two salts were not significantly different (Student t test, p < 0,05 but XTT allowed an easier visualization of positive wells due to product solubility of the reduce product. A greater percentage of isolates was obtained using XTT (67%, which suggests that salt type is relevant for recovering of these microorganisms. Additionally, cell detection limit, optimal conditions of XTT concentration and incubation times for detection of activity were evaluated. This evaluation was performed by means of microplate format for hydrocarbon degrading microorganisms using Acinetobacter sp. An inhibitory effect was observed in the recovering of cultivable cells when XTT

  13. Chlorine

    Science.gov (United States)

    ... Del.icio.us Digg Facebook Google Bookmarks Technorati Yahoo MyWeb Updates Subscribe Listen Page last reviewed April ... Del.icio.us Digg Facebook Google Bookmarks Technorati Yahoo MyWeb Download page Subscribe to RSS Get email ...

  14. Bioremediation: Technology for treating hydrocarbon-contaminated wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Towprayoon, S.; Kuntrangwattana, S. [King Mongkut`s Institute of Technology, Bangkok (Thailand)

    1996-12-31

    Cutting oil wastewater from an iron and steel factory was applied to the soil windrow. Self-remediation was then compared with remediation with acclimatized indigenous microbes. The incremental reduction rate of the microorganisms and hydrocarbon-degradable microbes was slower in self-remediation than in the latter treatment. Within 30 days, when the acclimatized indigenous microbes were used, there was a significant reduction of the contaminated hydrocarbons, while self-remediation took longer to reduce to the same concentration. Various nitrogen sources were applied to the soil pile, namely, organic compost, chemical fertilizer, ammonium sulfate, and urea. The organic compost induced a high yield of hydrocarbon-degradable microorganisms, but the rate at which the cutting oil in the soil decreased was slower than when other nitrogen sources were used. The results of cutting oil degradation studied by gas chromatography showed the absence of some important hydrocarbons. The increment of the hydrocarbon-degradable microbes in the land treatment ecosystem does not necessarily correspond to the hydrocarbon reduction efficiency. 3 refs., 3 figs.

  15. The dynamics of low-chlorinated benzenes in a pilot-scale constructed wetland and a hydroponic plant root mat treating sulfate-rich groundwater.

    Science.gov (United States)

    Chen, Zhongbing; Kuschk, Peter; Paschke, Heidrun; Kästner, Matthias; Köser, Heinz

    2015-03-01

    A rarely used hydroponic plant root mat filter (PRMF, of 6 m(2)) and a horizontal subsurface flow constructed wetland (HSSF CW, of 6 m(2)), operating in continuous flow and discontinuous outflow flushing modes, were investigated for treating sulfate-rich and organic carbon-lean groundwater contaminated with monochlorobenzene (MCB); 1,2-dichlorobenzene (1,2-DCB); 1,4-dichlorobenzene (1,4-DCB); and 2-chlorotoluene. Whereas the mean inflow loads ranged from 1 to 247 mg m(-2) days(-1), the range of mean inflow concentrations of the chlorobenzenes recorded over a period of 7 months was within 0.04 and 8 mg L(-1). A hydraulic surface loading rate of 30 L m(-2) days(-1) was obtained in both systems. The mean load removal efficiencies were found to vary between 87 and 93 % in the PRMF after a flow path of 4 m, while the removal efficiencies were found to range between 46 and 70 % and 71 to 73 % in the HSSF CW operating in a continuous flow mode and a discontinuous outflow flushing mode, respectively. Seasonal variations in the removal efficiencies were observed for all low-chlorinated hydrocarbons both in the PRMF and the HSSF CW, whereby the highest removal efficiencies were reached during the summer months. Sulfide formation occurred in the organic carbon-lean groundwater particularly in summer, which is probably due to the plant-derived organic carbon that fostered the microbial dissimilatory sulfate reduction. Higher redox potential in water was observed in the PRMF. In conclusion, the PRMF could be an option for the treatment of water contaminated with compounds which in particular need oxic conditions for their microbial degradation, such as in the case of low-chlorinated benzenes.

  16. The dynamics of low-chlorinated benzenes in a pilot-scale constructed wetland and a hydroponic plant root mat treating sulfate-rich groundwater.

    Science.gov (United States)

    Chen, Zhongbing; Kuschk, Peter; Paschke, Heidrun; Kästner, Matthias; Köser, Heinz

    2015-03-01

    A rarely used hydroponic plant root mat filter (PRMF, of 6 m(2)) and a horizontal subsurface flow constructed wetland (HSSF CW, of 6 m(2)), operating in continuous flow and discontinuous outflow flushing modes, were investigated for treating sulfate-rich and organic carbon-lean groundwater contaminated with monochlorobenzene (MCB); 1,2-dichlorobenzene (1,2-DCB); 1,4-dichlorobenzene (1,4-DCB); and 2-chlorotoluene. Whereas the mean inflow loads ranged from 1 to 247 mg m(-2) days(-1), the range of mean inflow concentrations of the chlorobenzenes recorded over a period of 7 months was within 0.04 and 8 mg L(-1). A hydraulic surface loading rate of 30 L m(-2) days(-1) was obtained in both systems. The mean load removal efficiencies were found to vary between 87 and 93 % in the PRMF after a flow path of 4 m, while the removal efficiencies were found to range between 46 and 70 % and 71 to 73 % in the HSSF CW operating in a continuous flow mode and a discontinuous outflow flushing mode, respectively. Seasonal variations in the removal efficiencies were observed for all low-chlorinated hydrocarbons both in the PRMF and the HSSF CW, whereby the highest removal efficiencies were reached during the summer months. Sulfide formation occurred in the organic carbon-lean groundwater particularly in summer, which is probably due to the plant-derived organic carbon that fostered the microbial dissimilatory sulfate reduction. Higher redox potential in water was observed in the PRMF. In conclusion, the PRMF could be an option for the treatment of water contaminated with compounds which in particular need oxic conditions for their microbial degradation, such as in the case of low-chlorinated benzenes. PMID:25280503

  17. Internal chlorination of Ni-Cr alloys

    Energy Technology Data Exchange (ETDEWEB)

    Berztiss, D.; Hennesen, K.; Grabke, H.J. [Max-Planck-Institut fuer Eisenforschung GmbH, Duesseldorf (Germany)

    1998-12-31

    In contrast to internal oxidation, sulfidation and carburization, very little information is available regarding internal chlorination, especially diffusion of chlorine in metallic alloys. This paper describes results of experiments on Ni-Cr alloys (<10 wt% Cr) exposed in an atmosphere containing radioactive HCl. The diffusion of chlorine in the alloy can be determined by measurement of residual {beta}-activity from the sample surface. Successively thin layers (0.5-10 {mu}m) of the alloy were removed by lapping and the surface activity was measured to obtain a depth profile. Both single and polycrystalline materials were tested. Through this work it should be determined if there is in fact solubility and diffusion of chlorine in Ni-based alloys as some authors have proposed or if the ingress of chlorine is mainly a grain boundary phenomenon. (orig.)

  18. Biodegradation of Chlorinated Solvents: Reactions near DNAPL and Enzyme Function

    International Nuclear Information System (INIS)

    three to five times, leading to a more rapid clean-up of the DNAPL zone. The most favored electron donor to add is one which partitions well with the chlorinated solvent or can be concentrated near it. Unfortunately, an ideal electron donor, such as vegetable oil, is difficult to introduce and mix with DNAPL in the ground, doing this properly remains an engineering challenge. Numerical model studies have indicated that several factors may significantly influence the rate and extent of enhancement, including the inhibitory effects of PCE and cDCE, the level of ED concentration, DNAPL configuration, and competition for ED. Such factors need to be considered when contemplating engineered DNAPL bioremediation. Pseudomonas stuzeri KC is an organism that transforms CT to carbon dioxide and chloride without the formation of the hazardous intermediate, chloroform. This is accomplished by production and secretion of a molecule called PDTC. This study was direct ed towards determining how PDTC works. Cu (II) at a ratio of 1:1 Cu to PDTC was found to result in the most rapid CT transformation, confirming that the PDTC-Cu complex is both a reactant and a catalyst in CT transformation. CT degradation requires that the PDTC be in a reduced form, which is generated by contact with cell components. Fe(II) inhibits CT transformation by PDTC. Studies indicated that this inhibition is enhanced by some compound or factor in the supernatant with molecular weight greater than 10,000 Da. We have made progress in determining what this factor might be, but have not yet been able to identify it. In related studies, we found that CT transformation by another organism, Shewanella oneidensis MR1, also involves an excreted factor, but this factor is different from PDTC and results in chloroform transformation as an intermediate. Our studies have indicated that this factor is similar to vitamin K2, and we have also confirmed that vitamin K2 does transform C T into chloroform

  19. Biodegradation of Chlorinated Solvents: Reactions near DNAPL and Enzyme Function

    Energy Technology Data Exchange (ETDEWEB)

    McCarty, P. L.; Spormann, Alfred M.; Criddle, Craig, S.

    2003-12-11

    three to five times, leading to a more rapid clean-up of the DNAPL zone. The most favored electron donor to add is one which partitions well with the chlorinated solvent or can be concentrated near it. Unfortunately, an ideal electron donor, such as vegetable oil, is difficult to introduce and mix with DNAPL in the ground, doing this properly remains an engineering challenge. Numerical model studies have indicated that several factors may significantly influence the rate and extent of enhancement, including the inhibitory effects of PCE and cDCE, the level of ED concentration, DNAPL configuration, and competition for ED. Such factors need to be considered when contemplating engineered DNAPL bioremediation. Pseudomonas stuzeri KC is an organism that transforms CT to carbon dioxide and chloride without the formation of the hazardous intermediate, chloroform. This is accomplished by production and secretion of a molecule called PDTC. This study was direct ed towards determining how PDTC works. Cu (II) at a ratio of 1:1 Cu to PDTC was found to result in the most rapid CT transformation, confirming that the PDTC-Cu complex is both a reactant and a catalyst in CT transformation. CT degradation requires that the PDTC be in a reduced form, which is generated by contact with cell components. Fe(II) inhibits CT transformation by PDTC. Studies indicated that this inhibition is enhanced by some compound or factor in the supernatant with molecular weight greater than 10,000 Da. We have made progress in determining what this factor might be, but have not yet been able to identify it. In related studies, we found that CT transformation by another organism, Shewanella oneidensis MR1, also involves an excreted factor, but this factor is different from PDTC and results in chloroform transformation as an intermediate. Our studies have indicated that this factor is similar to vitamin K2, and we have also confirmed that vitamin K2 does transform C T into chloroform.

  20. Estimation of rates of aerobic hydrocarbon biodegradation by simulation of gas transport in the unsaturated zone

    Science.gov (United States)

    Lahvis, Matthew A.; Baehr, Arthur L.

    1996-07-01

    The distribution of oxygen and carbon dioxide gases in the unsaturated zone provides a geochemical signature of aerobic hydrocarbon degradation at petroleum product spill sites. The fluxes of these gases are proportional to the rate of aerobic biodegradation and are quantified by calibrating a mathematical transport model to the oxygen and carbon dioxide gas concentration data. Reaction stoichiometry is assumed to convert the gas fluxes to a corresponding rate of hydrocarbon degradation. The method is applied at a gasoline spill site in Galloway Township, New Jersey, to determine the rate of aerobic degradation of hydrocarbons associated with passive and bioventing remediation field experiments. At the site, microbial degradation of hydrocarbons near the water table limits the migration of hydrocarbon solutes in groundwater and prevents hydrocarbon volatilization into the unsaturated zone. In the passive remediation experiment a site-wide degradation rate estimate of 34,400 gyr-1 (11.7 gal. yr-1) of hydrocarbon was obtained by model calibration to carbon dioxide gas concentration data collected in December 1989. In the bioventing experiment, degradation rate estimates of 46.0 and 47.9 gm-2yr-1 (1.45×10-3 and 1.51×10-3 gal.ft.-2yr-1) of hydrocarbon were obtained by model calibration to oxygen and carbon dioxide gas concentration data, respectively. Method application was successful in quantifying the significance of a naturally occurring process that can effectively contribute to plume stabilization.

  1. Estimation of rates of aerobic hydrocarbon biodegradation by simulation of gas transport in the unsaturated zone

    Science.gov (United States)

    Lahvis, M.A.; Baehr, A.L.

    1996-01-01

    The distribution of oxygen and carbon dioxide gases in the unsaturated zone provides a geochemical signature of aerobic hydrocarbon degradation at petroleum product spill sites. The fluxes of these gases are proportional to the rate of aerobic biodegradation and are quantified by calibrating a mathematical transport model to the oxygen and carbon dioxide gas concentration data. Reaction stoichiometry is assumed to convert the gas fluxes to a corresponding rate of hydrocarbon degradation. The method is applied at a gasoline spill site in Galloway Township, New Jersey, to determine the rate of aerobic degradation of hydrocarbons associated with passive and bioventing remediation field experiments. At the site, microbial degradation of hydrocarbons near the water table limits the migration of hydrocarbon solutes in groundwater and prevents hydrocarbon volatilization into the unsaturated zone. In the passive remediation experiment a site-wide degradation rate estimate of 34,400 g yr-1 (11.7 gal. yr-1) of hydrocarbon was obtained by model calibration to carbon dioxide gas concentration data collected in December 1989. In the bioventing experiment, degradation rate estimates of 46.0 and 47.9 g m-2 yr-1 (1.45 x 10-3 and 1.51 x 10-3 gal. ft.-2 yr-1) of hydrocarbon were obtained by model calibration to oxygen and carbon dioxide gas concentration data, respectively. Method application was successful in quantifying the significance of a naturally occurring process that can effectively contribute to plume stabilization.

  2. Validation study for crediting chlorine in criticality analyses for spent nuclear fuel disposition

    Energy Technology Data Exchange (ETDEWEB)

    Sobes, Vladimir [ORNL; Scaglione, John M [ORNL; Wagner, John C [ORNL; Dunn, Michael E [ORNL

    2015-01-01

    Spent nuclear fuel (SNF) management practices in the United States rely on dry storage systems that include both canister- and cask-based systems. The United States Department of Energy Used Fuel Disposition Campaign is examining the feasibility of direct disposal of dual-purpose (storage and transportation) canisters (DPCs) in a geological repository. One of the major technical challenges for direct disposal is the ability to demonstrate the subcriticality of the DPCs loaded with SNF for the repository performance period (e.g., 10,000 years or more) as the DPCs may undergo degradation over time. Specifically, groundwater ingress into the DPC (i.e., flooding) could allow the system to achieve criticality in scenarios where the neutron absorber plates in the DPC basket have degraded. However, as was shown by Banerjee et al., some aqueous species in the groundwater provide noticeable reactivity reduction for these systems. For certain amounts of particular aqueous species (e.g., chlorine, lithium) in the groundwater, subcriticality can be demonstrated even for DPCs with complete degradation of the neutron absorber plates or a degraded fuel basket configuration. It has been demonstrated that chlorine is the leading impurity, as indicated by significant neutron absorption in the water that is available in reasonable quantities for the deep geological repository media under consideration. This paper presents the results of an investigation of the available integral experiments worldwide that could be used to validate DPC disposal criticality evaluations, including credit for chlorine. Due to the small number of applicable critical configurations, validation through traditional trending analysis was not possible. The bias in the eigenvalue of the application systems due only to the chlorine was calculated using TSURFER analysis and found to be on the order of 100 percent mille (1 pcm = 10-5 keff). This study investigated the design of a series of

  3. Validation Study for Crediting Chlorine in Criticality Analyses for US Spent Nuclear Fuel Disposition

    Energy Technology Data Exchange (ETDEWEB)

    Sobes, Vladimir [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Scaglione, John M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wagner, John C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Dunn, Michael E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-01-01

    Spent nuclear fuel (SNF) management practices in the United States rely on dry storage systems that include both canister- and cask-based systems. The United States Department of Energy Used Fuel Disposition Campaign is examining the feasibility of direct disposal of dual-purpose (storage and transportation) canisters (DPCs) in a geological repository. One of the major technical challenges for direct disposal is the ability to demonstrate the subcriticality of the DPCs loaded with SNF for the repository performance period (e.g., 10,000 years or more) as the DPCs may undergo degradation over time. Specifically, groundwater ingress into the DPC (i.e., flooding) could allow the system to achieve criticality in scenarios where the neutron absorber plates in the DPC basket have degraded. However, as was shown by Banerjee et al., some aqueous species in the groundwater provide noticeable reactivity reduction for these systems. For certain amounts of particular aqueous species (e.g., chlorine, lithium) in the groundwater, subcriticality can be demonstrated even for DPCs with complete degradation of the neutron absorber plates or a degraded fuel basket configuration. It has been demonstrated that chlorine is the leading impurity, as indicated by significant neutron absorption in the water that is available in reasonable quantities for the deep geological repository media under consideration. This paper presents the results of an investigation of the available integral experiments worldwide that could be used to validate DPC disposal criticality evaluations, including credit for chlorine. Due to the small number of applicable critical configurations, validation through traditional trending analysis was not possible. The bias in the eigenvalue of the application systems due only to the chlorine was calculated using TSURFER analysis and found to be on the order of 100 percent mille (1 pcm = 10-5 keff). This study investigated the design of a series of

  4. Validation Study for Crediting Chlorine in Criticality Analyses for US Spent Nuclear Fuel Disposition

    International Nuclear Information System (INIS)

    Spent nuclear fuel (SNF) management practices in the United States rely on dry storage systems that include both canister- and cask-based systems. The United States Department of Energy Used Fuel Disposition Campaign is examining the feasibility of direct disposal of dual-purpose (storage and transportation) canisters (DPCs) in a geological repository. One of the major technical challenges for direct disposal is the ability to demonstrate the subcriticality of the DPCs loaded with SNF for the repository performance period (e.g., 10,000 years or more) as the DPCs may undergo degradation over time. Specifically, groundwater ingress into the DPC (i.e., flooding) could allow the system to achieve criticality in scenarios where the neutron absorber plates in the DPC basket have degraded. However, as was shown by Banerjee et al., some aqueous species in the groundwater provide noticeable reactivity reduction for these systems. For certain amounts of particular aqueous species (e.g., chlorine, lithium) in the groundwater, subcriticality can be demonstrated even for DPCs with complete degradation of the neutron absorber plates or a degraded fuel basket configuration. It has been demonstrated that chlorine is the leading impurity, as indicated by significant neutron absorption in the water that is available in reasonable quantities for the deep geological repository media under consideration. This paper presents the results of an investigation of the available integral experiments worldwide that could be used to validate DPC disposal criticality evaluations, including credit for chlorine. Due to the small number of applicable critical configurations, validation through traditional trending analysis was not possible. The bias in the eigenvalue of the application systems due only to the chlorine was calculated using TSURFER analysis and found to be on the order of 100 percent mille (1 pcm = 10-5 keff). This study investigated the design of a series of critical configurations

  5. Aqueous chlorination of mefenamic acid: kinetics, transformation by-products and ecotoxicity assessment.

    Science.gov (United States)

    Adira Wan Khalit, Wan Nor; Tay, Kheng Soo

    2016-05-18

    Mefenamic acid (Mfe) is one of the most frequently detected nonsteroidal anti-inflammatory drugs in the environment. This study investigated the kinetics and the transformation by-products of Mfe during aqueous chlorination. The potential ecotoxicity of the transformation by-products was also evaluated. In the kinetic study, the second-order rate constant (kapp) for the reaction between Mfe and free available chlorine (FAC) was determined at 25 ± 0.1 °C. The result indicated that the degradation of Mfe by FAC is highly pH-dependent. When the pH was increased from 6 to 8, it was found that the kapp for the reaction between Mfe and FAC was decreased from 16.44 to 4.4 M(-1) s(-1). Characterization of the transformation by-products formed during the chlorination of Mfe was carried out using liquid chromatography-quadrupole time-of-flight accurate mass spectrometry. Four major transformation by-products were identified. These transformation by-products were mainly formed through hydroxylation, chlorination and oxidation reactions. Ecotoxicity assessment revealed that transformation by-products, particularly monohydroxylated Mfe which is more toxic than Mfe, can be formed during aqueous chlorination.

  6. Organochlorine Turnover in Forest Ecosystems: The Missing Link in the Terrestrial Chlorine Cycle

    Energy Technology Data Exchange (ETDEWEB)

    A Leri; S Myneni

    2011-12-31

    Research in the last 20 years has shown that chlorine undergoes transformations between inorganic and organic forms as part of a complex biogeochemical cycle in terrestrial systems. Natural organochlorine production appears to be associated with the decomposition of plant material on the soil surface, though the chlorine cycle budget implies that a proportion of natural organochlorine enters soil through plant litter and atmospheric deposition as well. Organochlorine compounds may form through biotic and abiotic pathways, but the rates and magnitude of production in the field remain undefined. We have performed a time-dependent trace of chlorine concentration through forest ecosystems, revealing distinct fractions of naturally produced organochlorine in plant biomass. Aliphatic organochlorine constitutes an intrinsic component of healthy leaves that persists through senescence and humification of the plant material, making a substantial contribution to the pool of soil organochlorine. Plant leaves also contain soluble aromatic organochlorine compounds that leach from leaf litter during early decay stages. As decay progresses, high concentrations of insoluble aromatic organochlorine accrue in the humus, through de novo production as well as adsorption. The rates of aromatic organochlorine production and degradation vary seasonally and conversely. This study presents the first unambiguous evidence that there exist multiple pools of chlorinated organic matter in the soil environment and that leaf litter deposition makes a significant and refractory contribution to the soil organochlorine pool, providing key insights into the biogeochemical chlorine cycle.

  7. Organochlorine turnover in forest ecosystems: The missing link in the terrestrial chlorine cycle

    Science.gov (United States)

    Leri, Alessandra C.; Myneni, Satish C. B.

    2010-12-01

    Research in the last 20 years has shown that chlorine undergoes transformations between inorganic and organic forms as part of a complex biogeochemical cycle in terrestrial systems. Natural organochlorine production appears to be associated with the decomposition of plant material on the soil surface, though the chlorine cycle budget implies that a proportion of natural organochlorine enters soil through plant litter and atmospheric deposition as well. Organochlorine compounds may form through biotic and abiotic pathways, but the rates and magnitude of production in the field remain undefined. We have performed a time-dependent trace of chlorine concentration through forest ecosystems, revealing distinct fractions of naturally produced organochlorine in plant biomass. Aliphatic organochlorine constitutes an intrinsic component of healthy leaves that persists through senescence and humification of the plant material, making a substantial contribution to the pool of soil organochlorine. Plant leaves also contain soluble aromatic organochlorine compounds that leach from leaf litter during early decay stages. As decay progresses, high concentrations of insoluble aromatic organochlorine accrue in the humus, through de novo production as well as adsorption. The rates of aromatic organochlorine production and degradation vary seasonally and conversely. This study presents the first unambiguous evidence that there exist multiple pools of chlorinated organic matter in the soil environment and that leaf litter deposition makes a significant and refractory contribution to the soil organochlorine pool, providing key insights into the biogeochemical chlorine cycle.

  8. Examination of dioxin degradation conditions for geobacillus midousuji SH2B-J2

    Energy Technology Data Exchange (ETDEWEB)

    Hoshina, S. [Jikei Univ., School of Medicine, Tokyo (Japan); Ohtsuka, Y. [Forestry and Forest Products Research Instiute; Goda, H. [Towa Kagaku Co., Ltd.

    2004-09-15

    Cellular membrane degradation capability of SH2B-J2 strains for dioxin mixtures that are greater than tetra-chlorinated have been examined. Optimal temperature, reaction time, optimal pH, and heavy metal resistance of cellular membrane enzyme were investigated, to examine dioxin degradation characteristics of SH2B-J2 strains. For chlorinated dioxins, a mixture (PCDD/PCDF mix) containing 7 species of dibenzo-p-dioxins greater than tetra-chlorinated, as well as 10 isomers of dibenzofurans, was used. Using GC/MS, decrease of 17 species of dioxin isomer/congener was measured.

  9. Microbial Diversity and Bioremediation of a Hydrocarbon-Contaminated Aquifer (Vega Baja, Puerto Rico

    Directory of Open Access Journals (Sweden)

    Arturo A. Massol-Deyá

    2006-09-01

    Full Text Available Hydrocarbon contamination of groundwater resources has become a major environmental and human health concern in many parts of the world. Our objectives were to employ both culture and culture-independent techniques to characterize the dynamics of microbial community structure within a fluidized bed reactor used to bioremediate a diesel-contaminated groundwater in a tropical environment. Under normal operating conditions, 97 to 99% of total hydrocarbons were removed with only 14 min hydraulic retention time. Over 25 different cultures were isolated from the treatment unit (96% which utilized diesel constituents as sole carbon source. Approximately 20% of the isolates were also capable of complete denitrification to nitrogen gas. Sequence analysis of 16S rDNA demonstrated ample diversity with most belonging to the ∝, β and γ subdivision of the Proteobacteria, Bacilli, and Actinobacteria groups. Moreover, the genetic constitution of the microbial community was examined at multiple time points with a Functional Gene Array (FGA containing over 12,000 probes for genes involved in organic degradation and major biogeochemical cycles. Total community DNA was extracted and amplified using an isothermal φ29 polymerase-based technique, labeled with Cy5 dye, and hybridized to the arrays in 50% formimide overnight at 50°C. Cluster analysis revealed comparable profiles over the course of treatment suggesting the early selection of a very stable microbial community. A total of 270 genes for organic contaminant degradation (including naphthalene, toluene [aerobic and anaerobic], octane, biphenyl, pyrene, xylene, phenanthrene, and benzene; and 333 genes involved in metabolic activities (nitrite and nitrous oxide reductases [nirS, nirK, and nosZ], dissimilatory sulfite reductases [dsrAB], potential metal reducing C-type cytochromes, and methane monooxygenase [pmoA] were repeatedly detected. Genes for degradation of MTBE

  10. Development and in situ implementation of a chemical process for reductive dechlorination of chlorinated solvents in polluted aquifers

    OpenAIRE

    Betelu, Stéphanie; Rodrigues, Romain; Noel, Cécile; Colombano, Stéfan; Simon, Apolline; Epardeau, Patrick; Marion, Roland; Ignatiadis, Ioannis

    2015-01-01

    International audience Reductive dechlorination (RDC), using strong reducers, is one of the most important emerging remediation techniques for chlorinated hydrocarbons (CHC). RDC by Nanosized Zero Valent Iron (NZVI) is a powerful electrochemical redox system that has shown promising experimental results for the development of remediation technologies to treat contaminated sites [1, 2]. Although NZVI has excellent characteristics as environmental reactant, its application to the contaminate...

  11. Oil degrading microbial population along the Texas coast

    International Nuclear Information System (INIS)

    The quantity of petroleum degrading bacteria in the coastal waters of Texas was evaluated to determine if the number varies according to the oil contamination history of the sampling sites. In most of the collected water samples, saturate and polycyclic aromatic hydrocarbon (PAH) degraders exist, regardless of the site's contamination history. Saturate degraders are more abundant than PAH degraders and there may be a correlation between the quantity of hydrocarbon degraders at a given site and its proximity to anthropogenic petroleum activities. But the stronger direct association seems to be between the total heterotroph numbers and the hydrocarbon degrader numbers. Extensive studies are still underway to confirm these results. 22 refs., 1 tab., 4 figs

  12. Bioremediation of petroleum hydrocarbons in soil environments

    International Nuclear Information System (INIS)

    The bioremediation of petroleum hydrocarbons in soil environments was reviewed via a literature survey and discussions with workers in relevant disciplines. The impacts of hydrocarbons on soil are discussed along with a range of methods available to assist in their decomposition by soil microorganisms. The range of petroleum-based materials considered includes conventional and synthetic crude oils, refined oils, sludges, asphalts and bitumens, drilling mud residues, creosote tars, and some pesticides. The degradability of hydrocarbons largely depends upon their aqueous solubility and their adsorption on soil surfaces and, therefore, is related to their molecular structures. The ease of decomposition decreases with increasing complexity of structure, in the order aliphatics > aromatics > heterocyclics and asphaltenes (most recalcitrant). Most soils contain an adequate population of microorganisms and hence bioaugmentation may only be needed in special circumstances. Decomposition is fastest in soils where the hydrocarbon loading rate, aeration, nutrition, moisture, and pH are all optimized. At spill sites there is little control over the application rate, although containment measures can assist in either limiting contamination or distributing it more evenly. The enhancement of bioremediation is discussed in light of all these factors. Other techniques such as enhanced aeration, hydrocarbon decomposition by anaerobic processes, surfactants, and burning are also discussed. 211 refs., 11 figs., 10 tabs

  13. Plasmids and aromatic degradation in Sphingomonas for bioremediation : Aromatic ring cleavage genes in soil and rhizosphere

    OpenAIRE

    SipilÀ, Timo

    2009-01-01

    Microbial degradation pathways play a key role in the detoxification and the mineralization of polyaromatic hydrocarbons (PAHs), which are widespread pollutants in soil and constituents of petroleum hydrocarbons. In microbiology the aromatic degradation pathways are traditionally studied from single bacterial strains with capacity to degrade certain pollutant. In soil the degradation of aromatics is performed by a diverse community of micro-organisms. The aim of this thesis was to study biode...

  14. Sonolytic degradation of 2-chlorobiphenyl

    Institute of Scientific and Technical Information of China (English)

    张光明; 华天星; 常爱敏

    2004-01-01

    The sonolytic degradation of 2-chlorobiphenyl was investigated. Mass spectroscopy was used to detect the products of sonolytic degradation of 2-chlorobiphenyl. The results show that the products of sonolytic degradation, such as biphenyl, ethyl benzene, diethylbiphenyl, dibutylbiphenyl, phenol, propylphenol and di-tert-butyl phenol are produced by thermolysis and hydroxyl free radical reactions, in which biphenyl counts for almost 40%(mole fraction) of the mother compound and others are at trace level. Rapid accumulation of chloride ion shows quick dechlorination, and 78% organic chlorine is converted into chloride ion. Free radical scavengers, bicarbonate and carbonate, decrease the reaction rate of sonolytic degradation of 2-chlorobiphenyl significantly, and the pseudo 1st order rate constant of sonolytic degradation of 2-chlorobiphenyl decreases linearly with the natural logarithm of the concentration of the added free radical scavenger, showing that the pyrolysis and hydroxyl free radical reaction are the two major pathways for the sonolytic degradation of 2-chlorobiphenyl, in which the hydroxyl radical concentration is estimated to be 1 × 10 10mol/L.

  15. A comparison of the virucidal properties of chlorine, chlorine dioxide, bromine chloride and iodine.

    OpenAIRE

    Taylor, G R; Butler, M

    1982-01-01

    Chlorine dioxide, bromine chloride and iodine were compared with chlorine as virucidal agents. Under optimal conditions all disinfectants were effective at low concentrations, but each disinfectant responded differently to acidity and alkalinity. Disinfection by chlorine was impaired by the presence of ammonia, but the other disinfectants retained much of their potency. Disinfection of poliovirus by iodine resulted in structural changes in the virions as seen by electron micrroscopy, but the ...

  16. UV Irradiation Chlorine Dioxide Photocatalytic Oxidation of Simulated Fuchsine Wastewater by UV-Vis and Online FTIR Spectrophotometric Method

    OpenAIRE

    Jie Liu; Chunlei Huai; Na Li; Xiaomei Wang; Laishun Shi

    2012-01-01

    The photocatalyst TiO2/SiO2 was prepared and used for chlorine dioxide photocatalytic oxidation of simulated fuchsine wastewater under UV irradiation. The removal efficiency of fuchsine treated by photocatalytic oxidation process is higher than that of chemical oxidation process. By using UV-Vis and online FTIR analysis technique, the intermediates during the degradation process were obtained. The benzene ring in fuchsine was degraded into quinone and carboxylic acid and finally changed into ...

  17. Chlorination of organic material in different soil types

    OpenAIRE

    Gustavsson, Malin

    2009-01-01

    Research has shown that formation of chlorinated organic matter occurs naturally and that organic chlorine is as abundant as the chloride ion in organic soils. A large number of organisms are known to convert inorganic chloride (Clin) to organic chlorine (Clorg) (e.g. bacteria, lichen, fungi and algae) and some enzymes associated to these organisms are capable of chlorinating soil organic matter. The aim with the study was to compare organic matter chlorination rates in soils from several dif...

  18. Ozone depletion and chlorine loading potentials

    Science.gov (United States)

    Pyle, John A.; Wuebbles, Donald J.; Solomon, Susan; Zvenigorodsky, Sergei; Connell, Peter; Ko, Malcolm K. W.; Fisher, Donald A.; Stordal, Frode; Weisenstein, Debra

    1991-01-01

    The recognition of the roles of chlorine and bromine compounds in ozone depletion has led to the regulation or their source gases. Some source gases are expected to be more damaging to the ozone layer than others, so that scientific guidance regarding their relative impacts is needed for regulatory purposes. Parameters used for this purpose include the steady-state and time-dependent chlorine loading potential (CLP) and the ozone depletion potential (ODP). Chlorine loading potentials depend upon the estimated value and accuracy of atmospheric lifetimes and are subject to significant (approximately 20-50 percent) uncertainties for many gases. Ozone depletion potentials depend on the same factors, as well as the evaluation of the release of reactive chlorine and bromine from each source gas and corresponding ozone destruction within the stratosphere.

  19. Ash characteristics in controlled diode laser pyrolysis of chlorinated rubber

    Science.gov (United States)

    Peligrad, A. A.; Schmidt, M. J. J.; Li, L.; Spencer, J. T.

    2000-02-01

    This paper describes the effects of 60 W High Power Diode Laser (HPDL) beams on the removal of chlorinated rubber (CR) paint from concrete surfaces and the ash particles generated from this process. The physical characteristics, including shape and size distribution of the removed and collected airborne CR particles, down to a size of around 1 μm in diameter, were determined using optical microscopy and image analysis. The shape of the particles observed was highly irregular, displaying no symmetry. The size distribution of the collected particles was found to range between 1-2000 μm, with the maximum concentration being found between 29 and 60 μm. The chemical characteristics of the CR ash particles were investigated by means of ESEM and EDX techniques. From a comparative analysis, it was found that the concentration of chlorine within the CR material was significantly reduced after HPDL treatment. This, together with DTA/TGA results indicated a combustive degradation of the CR polymer through the interaction with the process gas, oxygen, and the laser irradiation. Also, a strong correlation between laser power and average particle sizes has been found, with higher powers generally producing larger particle sizes. Opposite effects have been found by changing the oxygen flow rate, with higher oxygen flow producing, on average, smaller particles. An interpretation of the combustion process, as well as a brief discussion on operational safety and environmental impact of the products is attempted.

  20. Key Factors Controlling the Applicability and Efficiency of Bioremediation of Chlorinated Ethenes In Situ

    Science.gov (United States)

    Zhang, M.; Yoshikawa, M.; Takeuchi, M.; Komai, T.

    2012-12-01

    Bioremediation has been considered as one of environmentally friendly and cost effective approaches for cleaning up the sites polluted by organic contaminants, such as chlorinated ethenes. Although bioremediation, in its widest sense, is not new, and many researches have been performed on bioremediation of different kinds of pollutants, an effective design and implication of in situ bioremediation still remains a challenging problem because of the complexity. Many factors may affect the applicability and efficiency of bioremediation of chlorinated ethenes in situ, which include the type and concentration of contaminants, biological, geological and hydro-geological conditions of the site, physical and chemical characteristics of groundwater and soils to be treated, as well as the constraints in engineering. In this presentation, an overview together with a detailed discussion on each factor will be provided. The influences of individual factors are discussed using the data obtained or cited from different sites and experiments, and thus under different environmental conditions. The results of this study illustrated that 1) the establishment of microbial consortium is of crucial importance for a complete degradation of chlorinated ethenes, 2) in situ control of favorable conditions for increasing microbial activities for bio-degradation through a designed pathway is the key to success, 3) the focus of a successful remediation system is to design an effective delivery process that is capable of producing adequate amendment mixing of contaminant-degrading bacteria, appropriate concentrations of electron acceptors, electron donors, and microbial nutrients in the subsurface treatment area.

  1. Chlorine Abundances in Cool Stars

    CERN Document Server

    Maas, Z G; Hinkle, K

    2016-01-01

    Chlorine abundances are reported in 15 evolved giants and one M dwarf in the solar neighborhood. The Cl abundance was measured using the vibration-rotation 1-0 P8 line of H$^{35}$Cl at 3.69851 $\\mu$m. The high resolution L-band spectra were observed using the Phoenix infrared spectrometer on the Kitt Peak Mayall 4m telescope. The average [$^{35}$Cl/Fe] abundance in stars with --0.72$<$[Fe/H]$<$0.20 is [$^{35}$Cl/Fe]=(--0.10$\\pm$0.15) dex. The mean difference between the [$^{35}$Cl/Fe] ratios measured in our stars and chemical evolution model values is (0.16$\\pm$0.15) dex. The [$^{35}$Cl/Ca] ratio has an offset of $\\sim$0.35 dex above model predictions suggesting chemical evolution models are under producing Cl at the high metallicity range. Abundances of C, N, O, Si, and Ca were also measured in our spectral region and are consistent with F and G dwarfs. The Cl versus O abundances from our sample match Cl abundances measured in planetary nebula and \\ion{H}{2} regions. In one star where both H$^{35}$Cl a...

  2. Formation of chlorinated organic compounds in fluidized bed combustion of recycled fuels

    International Nuclear Information System (INIS)

    Four tests of co-combustion of recycled fuels (REP) with peat and coal in the 15 kW fluidized bed reactor were performed. The recycled fuel was so-called dry fraction in four vessels sampling at Keltinmaeki. In three tests a part of peat energy was replaced with coal. The mixtures were prepared so that in all mixtures 25 % of energy was recycled fuel and 75 % was either peat or the mixture of peat and coal. The concentrations of polyaromatic hydrocarbons (PAH), polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) and chlorophenols decreased with increasing part of coal due to the increasing sulphur/chlorine ratio. Principal Component Analysis (PCA) and Partial Least Square regression analysis (PLS) showed that the chlorine, copper and sulphur contents of the fuel effected most on the concentrations of chlorophenols, chlorobenzenes, PCBs and PCDDs/PCDFs. Other variables influencing on a model were the lead concentration and the sulphur/chlorine ratio in fuel and the hydrogen chloride concentration of the flue gas. The concentrations of chlorophenols and chlorobenzenes were also significant for PCDD/PCDF concentrations in flue gas. The sulphur, chlorine, copper and chromium contents in fly ash and the temperature of the reactor influenced on the chlorophenol, chlorobenzene, PCB and PCDD/PCDF concentrations in fly ash. The chlorophenol and chlorobenzene contents in fly ash, the sulphur/chlorine ratio and the lead content in fuel, the sulphur dioxide, hydrogen chloride and carbon monoxide concentrations in flue gas had also influence on PCDD/PCDF concentrations in fly ash

  3. Microbial degradation of monocyclic and polycyclic aromatic hydrocarbons in case of limited pollutant availability with nitrate as a potential electron acceptor; Der mikrobielle Abbau mono- und polyzyklischer aromatischer Kohlenwasserstoffe bei einer begrenzten Schadstoffverfuegbarkeit mit Nitrat als potentiellem Elektronenakzeptor

    Energy Technology Data Exchange (ETDEWEB)

    Linke, C.

    2001-07-01

    The possibility of using natural degradation processes for long-term remediation of tar oil contaminated sites was investigated. Field studies have shown that microbial decomposition of pollutants does take place in many sites but that it is limited by limited availability of pollutants and oxygen in soil. The investigations focused on the activation of BTEX and PAH degradation in situ by nitrate in the absence or in the presence of oxygen. Tensides should be used in order to enhance the availability of pollutants in water, especially in the case of hardly water-soluble PAH. A large-scale experiment was carried out on tar oil contaminated terrain; it was found that the availability of oxygen and not of PAH is the limiting factor so that adding of surfactants will not improve pollutant degradation. In contrast, the adding of tensides would mean even higher concentrations of oxygen-depleting substances in soil. [German] In der vorliegenden Arbeit wurden im Hinblick auf langfristige Sanierungsstrategien fuer teeroelkontaminierte Standorte Moeglichkeiten der Nutzung natuerlicher Abbauvorgaenge untersucht. Zahlreiche Feldstudien belegen, dass ein mikrobieller Schadstoffabbau an vielen Standorten stattfindet, dieser jedoch sowohl durch eine begrenzte Schadstoffverfuegbarkeit als auch durch den im Untergrund nur begrenzt zur Verfuegung stehenden Sauerstoff limitiert wird. Ziel dieser Arbeit war es abzuklaeren, inwiefern ein BTEX- und PAK-Abbau in situ auch in Abwesenheit von Sauerstoff durch Nitrat allein oder durch Nitrat in Kombination mit Sauerstoff aktiviert werden kann. Um insbesondere fuer die schlecht wasserloeslichen PAK eine ausreichende Schadstoffverfuegbarkeit zu gewaehrleisten, sollten auch Tenside zur Erhoehung der im Wasser vorliegenden Schadstoffmenge eingesetzt werden. Aufbauend auf die Laboruntersuchungen wurde im Rahmen von VEGAS{sup ix} ein Grossversuch zum mikrobiellen PAK-Abbau im Abstrom einer simulierten Teeroelkontamination durchgefuehrt

  4. ORC-GAC-Fe0 system for the remediation of trichloroethylene and monochlorobenzene contaminated aquifer:1.Adsorption and degradation

    Institute of Scientific and Technical Information of China (English)

    LIN Qi; CHEN Ying-xu; Plagentz V.; Sch(a)fer D.; Dahmke A.

    2004-01-01

    Activities at a former Chemistry Triangle in Bitterfeld, Germany, resulted in contamination of groundwater with a mixture of trichloroethylene(TCE) and monochlorobenzene(MCB). The objective of this study was to develop a barrier system, which includes an ORC(oxygen release compounds) and GAC(granular activated carbon) layer for adsorption of MCB and bioregeneration of GAC, a Fe0layer for chemical reductive dechlorination of TCE and other chlorinated hydrocarbon in situ. A laboratory-scale column experiment was conducted to evaluate the feasibility of this proposed system. This experiment was performed using a series of continuous flow Teflon columns including an ORC column, a GAC column, and a Fe0 column. Simulated MCB and TCE contaminated groundwater was pumped upflow into this system at a flow rate of t. 1 ml/min. Results showed that 17%-50% of TCE and 28%-50% of MCB were dissipated in ORC column. Chloride ion, however, was not released, which suggest the dechlorination do not happen in ORC column. In GAC column, the adsorption of contaminants on activated carbon and their induced degradation by adapted microorganisms attached to the carbon surface were observed. Due to competitive exchange processes, TCE can be desorbed by MCB in GAC column and further degraded in iron column. The completely dechlorination rate of TCE was 0.16-0.18 cm-1, 1-4 magnitudes more than the formation rate of three dichloroethene isomers. Cis-DCE is the main chlorinated product, which can be cumulated in the system, not only depending on the formation rate and its decaying rate, but also the initial concentration of TCE.

  5. In Situ Bioremediation of Chlorinated Ethenes in Hydraulically-Tight Sediments: Challenges and Limitations

    Science.gov (United States)

    Zhang, M.; Yoshikawa, M.; Takeuchi, M.; Komai, T.

    2011-12-01

    Chlorinated ethenes, like perchloroethene (PCE) and trichloroethene (TCE), have been widely used by many industries, especially in developed countries like Japan. Because of their wide applications, lack of proper regulation, poor handing, storage and disposal practices in the past, chlorinated ethenes have become a type of the most prevalent contaminants for soils and groundwater pollution. For the sake of their degradability, bioremediation has been considered as a potentially cost-effective and environmentally friendly approach for cleanup of chlorinated ethenes in situ. In this presentation, we briefly overview the status of soil and groundwater pollution, the recent amendment of the Soil Contamination Countermeasures Act in Japan, comparison between the bioremediation and other techniques like pump and treat, and the mechanisms of reductive dechlorination, direct oxidation and co-metabolism of chlorinated ethenes. We then introduce and discuss some recent challenges and advancements in in-situ bioremediation including technologies for accelerating bio-degradation of chlorinated ethenes, technologies for assessing diffusive properties of dissolved hydrogen in hydraulically-tight soil samples, and combination of bioremediation with other techniques like electro-kinetic approach. Limiting factors that may cause incomplete remediation and/or ineffectiveness of bioremediation are examined from biochemical, geochemical and hydro-geological aspects. This study reconfirmed and illustrated that: 1) The key factor for an effective bioremediation is how to disperse a proper accelerating agent throughout the polluted strata, 2) The effective diffusion coefficient of dissolved hydrogen in geologic media is relatively big and is almost independent on their permeability, and 3) To effectively design and perform an accelerated bioremediation, a combination of natural migration with pressurized injection and/or other approaches, like electro-migration, for stimulating mass

  6. Bromate ion formation in dark chlorination and ultraviolet/chlorination processes for bromide-containing water

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Bormate (BrO3-) is a carcinogenic chemical produced in ozonation or chlorination of bromide-containing water. Although its formation in seawater with or without sunlight has been previously investigated, the formation of bromate in dilute solutions,particularly raw water for water treatment plant, is unknown. In this article, the results of bench scale tests to measure the formation rates of bromate formation in dilute solutions, including de-ionized water and raw water from Yangtze River, were presented in dark chlorination and ultraviolet (UV)/chlorination processes. And the effects of initial pH, initial concentration of NaOCl, and UV light intensity on bromate formation in UV/chlorination of the diluted solutions were investigated. Detectable bromate was formed in dark chlorination of the two water samples with a relatively slow production rate. Under routine disinfecting conditions, the amount of formed bromate is not likely to exceed the national standards (10 μg/L). UV irradiation enhanced the decay of free chlorine, and,simultaneously, 6.6%-32% of Br- was oxidized to BrO3-. And the formation of bromate exhibited three stages: rapid stage, slow stage and plateau. Under the experimental conditions (pH = 4.41-11.07, CCl2= 1.23-4.50 mg/L), low pH and high chlorine concentration favored the generation of bromate. High light intensity promoted the production rate of bromate, but decreased its total generation amount due to acceleration of chlorine decomposition.

  7. Photochemical degradation of crude oil in seawater

    Institute of Scientific and Technical Information of China (English)

    YANG Guipeng; ZHANG Li; SUN Xiaojing; JING Weiwen

    2006-01-01

    Photochemical degradation of crude oil in seawater is an important issue in marine environmental protection and is studied in this work. Results showed that petroleum hydrocarbons could be effectively degraded by the irradiation of high-pressure mercury light or natural sunlight. Photochemical reaction was controlled by various factors including light source, aquatic medium, heavy metal ion and photo-sensitizer. The rate of photo-degradation was fast at the initial stage of exposure, exhibiting a first-order reaction kinetic behavior. However, after irradiation for a few hours, the concentration of water-soluble fraction (WSF) of petroleum hydrocarbons stabilized. For all experimental conditions, the range of the photo-degradation rate is from 0.001 3 to 0.005 7/min.

  8. Atmospheric reactivity of alcohols, thiols and fluoroalcohols with chlorine atoms

    Science.gov (United States)

    Garzon Ruiz, Andres

    Alcohols, thiols and fluoroalcohols are volatile organic compounds (VOCs) which are emitted to the atmosphere from both natural (vegetation, oceans, volcanoes, etc.) and anthropogenic sources (fuels, solvents, wastewater, incinerators, refrigerants, etc.). These pollutants can be eliminated from the troposphere by deposition on the terrestrial surface, direct photolysis or reaction with different tropospheric oxidants. Reactions of VOCs with tropospheric oxidants are involved in the well-known atmospheric phenomenon of photochemical smog or the production of tropospheric ozone. The oxidation of these VOCs in the troposphere is mainly initiated by reaction with OH radicals during the daytime and with NO radicals at night. However, in recent years, the oxidation by chlorine atoms (Cl) has gained great importance in the study of atmospheric reactions because they may exert some influence in the boundary layer, particularly in marine and coastal environments. In general, Cl atoms are much more reactive species than OH and NO; radicals and therefore low concentrations of Cl may compete with OH and NO3 in hydrocarbon oxidation processes. The main source of tropospheric Cl atoms is believed to be the photolysis of chlorine-containing molecules generated by heterogeneous reactions of sea salt aerosols. It has also been proposed that Cl atoms, produced in the photolysis of Cl2 emitted from industrial processes, may enhance hydrocarbon oxidation rates and ozone production in urban environments. In this work, a kinetic, theoretical and mechanistic study of the reaction of several alcohols, thiols, and fluoroalcohols with Cl atoms has been carried out. Pulsed laser photolysis-fluorescence resonance (PLP-RF) technique was used for the kinetic study as a function of temperature and pressure. An environmental chamber-Fourier transform infrared (FTIR) system was also employed in the kinetic studies. Tropospheric lifetimes of these pollutants were estimated using obtained kinetic

  9. Photochemical and microbial degradation technologies to remove toxic chemicals

    International Nuclear Information System (INIS)

    An effort was made to apply photochemical degradation technology on biodegradation processes to increase the bioremediation potential of microbial actions. For this purpose, we have chosen Phanerochaete chrysosporium, a wood decaying white-rot fungus and a variety of chlorinated pesticides and aromatics as study materials. By using UV-irradiation and benomyl (a commonly used fungicide) as selection methods, a strain of UV-resistant P. chrysosporium was developed. This strain was found to be capable of rapidly degrading these chlorinated chemicals when they were incubated in N-deficient medium which received 1 hr/day of UV-irradiation. UV-irradiation either at 300 or 254 nm showed the beneficial effect of speeding up the rate of degradation on most of test chemicals with the exception of toxaphene and HCH (hexachlorocyclohexane). By adding fresh glucose to the medium it was possible to maintain high degradation capacity for several weeks

  10. 31P nuclear magnetic resonance studies of effects of some chlorophenols on Escherichia coli and a pentachlorophenol-degrading bacterium.

    OpenAIRE

    Steiert, J G; Thoma, W J; Ugurbil, K; Crawford, R L

    1988-01-01

    A Flavobacterium sp. that mineralizes pentachlorophenol degrades some, but not all, of the other chlorinated phenols. Whole-cell 31P nuclear magnetic resonance was used to compare and observe transmembrane pH gradients and nucleotide pools in the Flavobacterium sp. and Escherichia coli after pentachlorophenol and 3,4,5-trichlorophenol were added to the cell suspensions. The data suggest that those chlorinated phenols which are not degraded by the Flavobacterium sp. may be resistant to degrada...

  11. The hydrocarbon generation mechanism and the threestage type model of hydrocarbon generation for carbonate source rocks

    Institute of Scientific and Technical Information of China (English)

    王兆云; 程克明

    1997-01-01

    The diagenetic mechanism and process of carbonate rocks, which is different to that of clastic rocks, decides the existence of different existing state organic matters in carbonate rocks. This has been verified by both the microscopic observation of organic petrology and the analysis of organic geochemistry of many samples. Based on the hydrous pyrolysis simulation experiment of the low-mature carbonate rocks, the contrasting study on the yield and their geochemistry characteristics of different existing state soluble organic matters of a series of various maturity samples shows that the different existing state organic matters make different contributions to hydrocarbon generation during every evolution state. So that, the hydrocarbon generation process of carbonate rocks can be summarized as the following three stages; the first is the direct degradation of biogenic bitumen macromolecules during the immature stage, the second is the thermal degradation of a large amount of kerogen at the mature stage,

  12. Partially oxidized polycyclic aromatic hydrocarbons show an increased bioavailability and biodegradability.

    NARCIS (Netherlands)

    Meulenberg, R.; Rijnaarts, H.H.M.; Doddema, H.J.; Field, J.A.

    1997-01-01

    Polycyclic aromatic hydrocarbons have a low water solubility and tend to adsorb on soil particles, which both result in slow bioremediation processes. Many microorganisms, known for their ability to degrade polycyclic aromatic hydrocarbons, only partially oxidize these compounds. White rot fungi, fo

  13. Determination of chlorinated polycyclic aromatic hydrocarbons in dust by solid-phase extract(SPE) and gas chromatofraphy-mass spectrometry%固相萃取/气相色谱质谱法测定灰尘中的氯代多环芳烃

    Institute of Scientific and Technical Information of China (English)

    郑继三; 马静; Yuichi Horii; Kurunthachalam Kannan; Takeshi Ohura; 徐刚; 吴明红

    2012-01-01

    A method was developed for the detection of 20 chlorinated polycyclic hydrocarbons(ClPAHs) in dust samples by solid-phase extract(SPE) and gas chromatography-mass spectrometry(GC/MS).The samples were Soxhlet extracted with dichloromethane-hexane mixture for more than 16 h.The extracts were purified through activated silica gel glass column,and then the SPE column self-packed with activated carbon-blended silica gel mixture.After cleanup,the extracts were analyzed by GC/MS in SIM mode,using characteristic ions for quantification.The SPE packed with a 0.2 g mixture of activated carbon-blended silica gel(1 ∶ 40,W/W) was found to have a good selectivity in separating ClPAHs from interference.And it reduced the toxic eluate when the SPE column was back-flushed after the sample extracts were loaded.The linear range,recovery and MDLs of 20 ClPAHs were examined.The recoveries of ClPAHs ranged from 60.4% to 120.1%,and the correlation coefficient was more than 0.99.The pretreatment procedure of this method is easy,and the quantification is sensitive and accurate.The method can be used to detect ClPAHs in many ambient media.%建立了固相萃取(SPE)/气相色谱质谱(GC/MS)联用检测灰尘中氯代多环芳烃(ClPAHs)的方法.以正己烷和二氯甲烷混合液为提取溶剂,索氏提取灰尘样品中的20种ClPAHs,活性硅胶层析柱与活性炭混合硅胶SPE柱协同净化.净化后的提取液采用GC/MS测定,SIM模式扫描,并用质谱特征离子定量分析.结果表明,填充量为0.2 g(W(活性炭)∶W(硅胶)=1∶40)的活性炭混合硅胶SPE小柱能有效地将ClPAHs分离出来,载样后采用反向溶剂洗脱,既提高了回收率又减少了洗脱剂甲苯的用量,净化效果好.处理灰尘样品后检测分析,20种ClPAHs的平均回收率稳定在60.4%—120.1%,相关系数〉0.99,检出限为0.04—0.17 ng.g-1,相对标准偏差为1.6%—10.2%.本方法前处理简单,定性、定量准确可靠,

  14. Limited degradation of chlorophenols by anaerobic sludge granules.

    OpenAIRE

    Mohn, W W; Kennedy, K J

    1992-01-01

    To better understand the fate of chlorophenols treated in upflow anaerobic sludge bed reactors, we examined the ability of sludge granules from such bioreactors to degrade two trichlorophenols and one dichlorophenol in batch incubations under controlled conditions. Biodegradation was primarily limited to two distinct activities, reductive dehalogenation of ortho- and of meta-chlorine substituents. Both 3- and 4-monochlorophenol were persistent degradation products, while 2-monochlorophenol wa...

  15. Sand amendment enhances bioelectrochemical remediation of petroleum hydrocarbon contaminated soil.

    Science.gov (United States)

    Li, Xiaojing; Wang, Xin; Ren, Zhiyong Jason; Zhang, Yueyong; Li, Nan; Zhou, Qixing

    2015-12-01

    Bioelectrochemical system is an emerging technology for the remediation of soils contaminated by petroleum hydrocarbons. However, performance of such systems can be limited by the inefficient mass transport in soil. Here we report a new method of sand amendment, which significantly increases both oxygen and proton transports, resulting to increased soil porosity (from 44.5% to 51.3%), decreased Ohmic resistance (by 46%), and increased charge output (from 2.5 to 3.5Cg(-1)soil). The degradation rates of petroleum hydrocarbons increased by up to 268% in 135d. The degradation of n-alkanes and polycyclic aromatic hydrocarbons with high molecular weight was accelerated, and denaturing gradient gel electrophoresis showed that the microbial community close to the air-cathode was substantially stimulated by the induced current, especially the hydrocarbon degrading bacteria Alcanivorax. The bioelectrochemical stimulation imposed a selective pressure on the microbial community of anodes, including that far from the cathode. These results suggested that sand amendment can be an effective approach for soil conditioning that will enhances the bioelectrochemical removal of hydrocarbons in contaminated soils. PMID:26135976

  16. Shelf-Life of Chlorine Solutions Recommended in Ebola Virus Disease Response

    Science.gov (United States)

    Iqbal, Qais; Lubeck-Schricker, Maya; Wells, Emma; Lantagne, Daniele

    2016-01-01

    In Ebola Virus Disease (EVD) outbreaks, it is widely recommended to wash living things (handwashing) with 0.05% (500 mg/L) chlorine solution and non-living things (surfaces, personal protective equipment, dead bodies) with 0.5% (5,000 mg/L) chlorine solution. Chlorine solutions used in EVD response are primarily made from powdered calcium hypochlorite (HTH), granular sodium dichloroisocyanurate (NaDCC), and liquid sodium hypochlorite (NaOCl), and have a pH range of 5–11. Chlorine solutions degrade following a reaction highly dependent on, and unusually sensitive to, pH, temperature, and concentration. We determined the shelf-life of 0.05% and 0.5% chlorine solutions used in EVD response, including HTH, NaDCC, stabilized NaOCl, generated NaOCl, and neutralized NaOCl solutions. Solutions were stored for 30 days at 25, 30, and 35°C, and tested daily for chlorine concentration and pH. Maximum shelf-life was defined as days until initial concentration fell to 30 days. Models were developed for solutions with maximum shelf-lives between 1–30 days. Extrapolating to 40°C, the maximum predicted shelf-life for 0.05% and 0.5% NaDCC solutions were 0.38 and 0.82 hours, respectively; predicted shelf-life for 0.05% and 0.5% generated NaOCl solutions were >30 and 5.4 days, respectively. Each chlorine solution type offers advantages and disadvantages to responders, as: NaDCC is an easy-to-import high-concentration effervescent powder; HTH is similar, but forms a precipitate that may clog pipes; and, NaOCl solutions can be made locally, but are difficult to transport. We recommend responders chose the most appropriate source chlorine compound for their use, and ensure solutions are stored at appropriate temperatures and used or replaced before expiring. PMID:27244552

  17. Shelf-Life of Chlorine Solutions Recommended in Ebola Virus Disease Response.

    Directory of Open Access Journals (Sweden)

    Qais Iqbal

    Full Text Available In Ebola Virus Disease (EVD outbreaks, it is widely recommended to wash living things (handwashing with 0.05% (500 mg/L chlorine solution and non-living things (surfaces, personal protective equipment, dead bodies with 0.5% (5,000 mg/L chlorine solution. Chlorine solutions used in EVD response are primarily made from powdered calcium hypochlorite (HTH, granular sodium dichloroisocyanurate (NaDCC, and liquid sodium hypochlorite (NaOCl, and have a pH range of 5-11. Chlorine solutions degrade following a reaction highly dependent on, and unusually sensitive to, pH, temperature, and concentration. We determined the shelf-life of 0.05% and 0.5% chlorine solutions used in EVD response, including HTH, NaDCC, stabilized NaOCl, generated NaOCl, and neutralized NaOCl solutions. Solutions were stored for 30 days at 25, 30, and 35°C, and tested daily for chlorine concentration and pH. Maximum shelf-life was defined as days until initial concentration fell to 30 days. Models were developed for solutions with maximum shelf-lives between 1-30 days. Extrapolating to 40°C, the maximum predicted shelf-life for 0.05% and 0.5% NaDCC solutions were 0.38 and 0.82 hours, respectively; predicted shelf-life for 0.05% and 0.5% generated NaOCl solutions were >30 and 5.4 days, respectively. Each chlorine solution type offers advantages and disadvantages to responders, as: NaDCC is an easy-to-import high-concentration effervescent powder; HTH is similar, but forms a precipitate that may clog pipes; and, NaOCl solutions can be made locally, but are difficult to transport. We recommend responders chose the most appropriate source chlorine compound for their use, and ensure solutions are stored at appropriate temperatures and used or replaced before expiring.

  18. In situ thermally enhanced biodegradation of petroleum fuel hydrocarbons and halogenated organic solvents

    International Nuclear Information System (INIS)

    An in situ thermally enhanced microbial remediation strategy and a method for the biodegradation of toxic petroleum fuel hydrocarbon and halogenated organic solvent contaminants are described. The method utilizes nonpathogenic, thermophilic bacteria for the thermal biodegradation of toxic and carcinogenic contaminants, such as benzene, toluene, ethylbenzene and xylenes, from fuel leaks and the chlorinated ethenes, such as trichloroethylene, chlorinated ethanes, such as 1,1,1-trichloroethane, and chlorinated methanes, such as chloroform, from past solvent cleaning practices. The method relies on and takes advantage of the pre-existing heated conditions and the array of delivery/recovery wells that are created and in place following primary subsurface contaminant volatilization efforts via thermal approaches, such as dynamic underground steam-electrical heating. 21 figs

  19. Investigation of molybdenum pentachloride interaction with chlorine

    International Nuclear Information System (INIS)

    In Raman spectra of molybdenum pentachloride solutions in liquid chlorine lines were recorded in case of 397, 312, 410, 217 and 180 cm-1 vibrations of ν1(A1'), ν2(A1'), ν5(E'), ν6(E') and ν8(E'') monomer (symmetry D3h) molecules of MoCl5. Interaction of molten molybdenum pentachloride with chlorine at increased (up to 6 MPa) pressures of Cl2 was studied. In Raman spectra of its vapour distillation in liquid chlorine alongside with MoCl5 lines appearance of new lines at 363 and 272 cm-1, similar in their frequency to the ones calculated for the vibrations ν1(A1g) and ν2(Eg) of MoCl6 molecules (symmetry Oh), was observed

  20. Studies concerning thermodynamics and kinetics of the absorption of halogenated hydrocarbons relevant to environment

    International Nuclear Information System (INIS)

    In the context of the research project the scrubbing of air contaminated by peculiar volatile organic compounds was investigated using the absorption technique by means of high boiling organics as washing liquids. Eight chlorinated hydrocarbons well known from technical processes were chosen to be representative for the volatile organic compounds. Eleven absorption media were selected on the basis of their physical properties. For the determination of the solubility data of the absorption media due to chlorinated hydrocarbons, nitrogen as well as a mixture of nitrogen and oxygen were used as carrier gas. The influence of the dipole moment of the absorption media on the amount of solubility - expressed as enrichment factor - was studied, too. Concerning the technical application, the thermostability and the stability against diluted inorganic acids were studied as well. (orig.). 56 figs., 8 tabs., 63 refs

  1. Investigation of degradation products of cocaine and benzoylecgonine in the aquatic environment

    Energy Technology Data Exchange (ETDEWEB)

    Bijlsma, Lubertus; Boix, Clara [Research Institute for Pesticides and Water, University Jaume I, Avda. Sos Baynat, E-12071 Castellón (Spain); Niessen, Wilfried M.A. [hyphen MassSpec, Leiden (Netherlands); Ibáñez, María; Sancho, Juan V. [Research Institute for Pesticides and Water, University Jaume I, Avda. Sos Baynat, E-12071 Castellón (Spain); Hernández, Félix, E-mail: felix.hernandez@uji.es [Research Institute for Pesticides and Water, University Jaume I, Avda. Sos Baynat, E-12071 Castellón (Spain)

    2013-01-15

    In this work, ultra-high-performance liquid chromatography (UHPLC) coupled to a hybrid quadrupole time-of-flight mass spectrometer (QTOF MS) has allowed the discovery and elucidation of degradation products of cocaine and its main metabolite benzoylecgonine (BE) in water. Spiked surface water was subjected to hydrolysis, chlorination and photo-degradation (both ultraviolet irradiation and simulated sunlight). After degradation of cocaine, up to sixteen compounds were detected and tentatively identified (1 resulting from hydrolysis; 8 from chlorination; 7 from photo-degradation), three of which are well known cocaine metabolites (BE, norbenzoylecgonine and norcocaine). Regarding BE degradation, up to ten compounds were found (3 from chlorination; 7 from photo-degradation), including one known metabolite (norbenzoylecgonine). Since reference standards were available for the major metabolites, they could be confirmed using information on retention time and fragment ions. The other degradates resulted from chlorination, dealkylation, hydroxylation and nitration, or from a combination of these processes. Several influent and effluent sewage water, and surface water samples were then screened for the identified compounds (known and unknown) using UHPLC–tandem MS with triple quadrupole. BE, norcocaine and norbenzoylecgonine were identified in these samples as major metabolites. Four previously unreported degradates were also found in some of the samples under study, illustrating the usefulness and applicability of the degradation experiments performed in this work. Highlights: ► Cocaine and benzoylecgonine degradation/transformation products investigated in water ► Hydrolysis, chlorination and photo degradation studied under laboratory conditions ► Several TPs discovered and tentatively elucidated by high resolution MS ► Structures of non-previously reported TPs have been suggested. ► Several reported/known TPs but also new TPs were found in sewage and surface

  2. Of cabbages and chlorine: cholera in Peru.

    Science.gov (United States)

    1992-07-01

    The low case fatality rates (1%) from the 1991 cholera epidemic in Peru was more a result of including diarrheas of a less virulent etiology than that of cholera. In fact, a study during the early phases of the cholera epidemic in Trujillo, Peru revealed that only 79% of suspected cholera cases were infected with vibrio cholera 01. Further other people contended that the government of Peru did not chlorinate many water supplies because studies by the US Environmental Protection Agency suggested that chlorine increases the cancer risk. It reacts with organic matter to make trihalomethanes. 1 study noted that this risk may explain as many as 700 cases of cancer/year in the US, yet cholera was responsible for nearly 40009 deaths in Latin America the 1st year. Besides in Trujillo, Peru the reason for not chlorinating the water supply was not due to a conscious decision to not do so on the part of the government, but because no funds had been made available to purchase chlorinators and chlorine. This is typical of many towns in developing countries. Further raw fish also played a role in transmitting cholera in Peru. Moreover the study in Trujillo indicated that water stored in containers in the home, and not the water supply, was the most important vehicle of transmission. Nevertheless chlorination of both the water supply and stored water would have prevented cholera transmission. In addition, cabbage irrigated with raw wastewater contributed to cholera transmission in Trujillo. But a concern arises if developing countries follow the advice of WHO of 1st treating wastewater in stabilization ponds. Aquatic blue green algae, other zooplankton, and phytoplankton from a microhabitat suitable for V. cholera. In fact, a study in Peru identified a seasonal pattern of the cholera epidemic with the seasonality of V. cholera non-01 from sewage lagoons in Lima. PMID:1351603

  3. Hydrocarbon pollutants shape bacterial community assembly of harbor sediments

    KAUST Repository

    Barbato, Marta

    2016-02-02

    Petroleum pollution results in co-contamination by different classes of molecules, entailing the occurrence of marine sediments difficult to remediate, as in the case of the Ancona harbor (Mediterranean Sea, Italy). Autochthonous bioaugmentation (ABA), by exploiting the indigenous microbes of the environment to be treated, could represent a successful bioremediation strategy. In this perspective we aimed to i) identify the main drivers of the bacterial communities\\' richness in the sediments, ii) establish enrichment cultures with different hydrocarbon pollutants evaluating their effects on the bacterial communities\\' composition, and iii) obtain a collection of hydrocarbon degrading bacteria potentially exploitable in ABA. The correlation between the selection of different specialized bacterial populations and the type of pollutants was demonstrated by culture-independent analyses, and by establishing a collection of bacteria with different hydrocarbon degradation traits. Our observations indicate that pollution dictates the diversity of sediment bacterial communities and shapes the ABA potential in harbor sediments.

  4. Hydrocarbon pollutants shape bacterial community assembly of harbor sediments.

    Science.gov (United States)

    Barbato, Marta; Mapelli, Francesca; Magagnini, Mirko; Chouaia, Bessem; Armeni, Monica; Marasco, Ramona; Crotti, Elena; Daffonchio, Daniele; Borin, Sara

    2016-03-15

    Petroleum pollution results in co-contamination by different classes of molecules, entailing the occurrence of marine sediments difficult to remediate, as in the case of the Ancona harbor (Mediterranean Sea, Italy). Autochthonous bioaugmentation (ABA), by exploiting the indigenous microbes of the environment to be treated, could represent a successful bioremediation strategy. In this perspective we aimed to i) identify the main drivers of the bacterial communities' richness in the sediments, ii) establish enrichment cultures with different hydrocarbon pollutants evaluating their effects on the bacterial communities' composition, and iii) obtain a collection of hydrocarbon degrading bacteria potentially exploitable in ABA. The correlation between the selection of different specialized bacterial populations and the type of pollutants was demonstrated by culture-independent analyses, and by establishing a collection of bacteria with different hydrocarbon degradation traits. Our observations indicate that pollution dictates the diversity of sediment bacterial communities and shapes the ABA potential in harbor sediments. PMID:26849913

  5. Occupational exposure to chlorinated and petroleum solvents and mycosis fungoides

    DEFF Research Database (Denmark)

    Morales-Suárez-Varela, Maria M; Olsen, Jørn; Villeneuve, Sara;

    2013-01-01

    To evaluate the potential association between occupational exposure to chlorinated and petroleum solvents and mycosis fungoides (MF).......To evaluate the potential association between occupational exposure to chlorinated and petroleum solvents and mycosis fungoides (MF)....

  6. The effects of low level chlorination and chlorine dioxide on biofouling control in a once-through service water system

    International Nuclear Information System (INIS)

    Continuous chlorination has been successfully used for the control of Corbicula at a nuclear power plant located on the Chattahoochee River in southeastern Alabama, since 1986. The purpose of this study was to investigate further minimization of chlorine usage and determine if chlorine dioxide is a feasible alternative. Four continuous biocide treatments were evaluated for macro and microfouling control effectiveness, operational feasibility, and environmental acceptability. One semi-continuous chlorination treatment was also evaluated for macrofouling control effectiveness. Higher treatment residuals were possible with chlorine dioxide than with chlorination due to the river discharge limitations. At the levels tested, continuous chlorine dioxide was significantly more effective in providing both macro and microfouling control. Semi-continuous chlorination was just as effective as continuous chlorination for controlling macrofouling. The Corbicula treatment programs that were tested should all provide sufficient control for zebra mussels. Chlorine dioxide was not as cost effective as chlorination for providing macrofouling control. The semi-continuous treatment save 50% on chemical usage and will allow for the simultaneous treatment of two service water systems. Chlorite levels produced during the chlorine dioxide treatments were found to be environmentally acceptable. Levels of trihalomethanes in the chlorinated service water were less than the maximum levels allowed in drinking water

  7. Biodegradation of Petroleum Hydrocarbons in Soil

    Directory of Open Access Journals (Sweden)

    MR Mehrasbi

    2003-09-01

    Full Text Available Biodegradation of petroleum hydrocarbons (20 g/kg dw soil was investigated in 3 media, differing in the kind of petroleum fractions. In the laboratory experiments, during 5 months, the activities of petroleum hydrocarbon-degrading microorganisms and dehydrogenase activity of soil was determined. Gas chromatographic analysis showed the biological decontaminations for gas oil, kerosene and synthetic mixture (gas oil, kerosene and furnace oil are 60 %, 36 % and 55 %, respectively. Dehydrogenase activity which was assessed by TTC technique, correlated significantly positive with the numbers of microorganisms. The Spearman rank correlation coefficients(r in contaminated soils with gas oil, kerosene and synthetic mixture were 0.79, 0.80 and 0.69, respectively.

  8. Review of chlorination of zirconium dioxide

    International Nuclear Information System (INIS)

    A review of chlorination zirconium dioxide is presented.used semi batch process with vertical reactor, horizontal reactor and fluidized reactor. The feed were zircon dioxide from Aldrich, direct zircon sand and briquette of zircon sand. From the study it is obtained that the best reactor is vertical reactor.It needs modification of chlorination reactor and sublimator to obtain the larger conversion. It is come to reality that zirconium tetrachloride preparation by process is significant with zirconium tetrachloride from Aldrich. It needs the sequel research to get the best result of process. (author)

  9. Determination of chlorine in silicate rocks

    Science.gov (United States)

    Peck, L.C.

    1959-01-01

    In a rapid accurate method for the determination of chlorine in silicate rocks, the rock powder is sintered with a sodium carbonate flux containing zinc oxide and magnesium carbonate. The sinter cake is leached with water, the resulting solution is filtered, and the filtrate is acidified with nitric acid. Chlorine is determined by titrating this solution with mercuric nitrate solution using sodium nitroprusside as the indicator. The titration is made in the dark with a beam of light shining through the solution. The end point of the titration is found by visually comparing the intensity of this beam of light with that of a similar beam of light in a reference solution.

  10. Attacks of Asthma due to Chlorinized Water: Case Report

    OpenAIRE

    Murat Eyup Berdan; Ercan Gocgeldi; Sami Ozturk; Ali Kutlu

    2008-01-01

    The presence of a high prevalence of bronchial hyperresponsiveness and asthma-like symptoms in swimmers has been reported. But, attacks of asthma which is related to chlorinized water is rare. Chlorine, a strong oxidizing agent, is an important toxic gas that the swimmer can breath during swimming and a worker can exposed to chlorine while he or she was using water with chlorine at home. We describe a persistent increase in nonspecific bronchial hyperresponsiveness following chronic exposure ...

  11. Chlorine-rich plasma polymer coating for the prevention of attachment of pathogenic fungal cells onto materials surfaces

    Science.gov (United States)

    Lamont-Friedrich, Stephanie J.; Michl, Thomas D.; Giles, Carla; Griesser, Hans J.; Coad, Bryan R.

    2016-07-01

    The attachment of pathogenic fungal cells onto materials surfaces, which is often followed by biofilm formation, causes adverse consequences in a wide range of areas. Here we have investigated the ability of thin film coatings from chlorinated molecules to deter fungal colonization of solid materials by contact killing of fungal cells reaching the surface of the coating. Coatings were deposited onto various substrate materials via plasma polymerization, which is a substrate-independent process widely used for industrial coating applications, using 1,1,2-trichloroethane as the process vapour. XPS surface analysis showed that the coatings were characterized by a highly chlorinated hydrocarbon polymer nature, with only a very small amount of oxygen incorporated. The activity of these coatings against human fungal pathogens was quantified using a recently developed, modified yeast assay and excellent antifungal activity was observed against Candida albicans and Candida glabrata. Plasma polymer surface coatings derived from chlorinated hydrocarbon molecules may therefore offer a promising solution to preventing yeast and mould biofilm formation on materials surfaces, for applications such as air conditioners, biomedical devices, food processing equipment, and others.

  12. A hand-portable instrument system for the real-time analysis of chlorinated organic compound contamination

    International Nuclear Information System (INIS)

    Working with the DOE Morgantown Energy Technology Center, Transducer Research, Inc. (TRI) recently developed a new chemical monitor which responds selectively to vapors of chlorinated solvents. No response is observed with common hydrocarbon organic compounds such as BTXs (benzene, toluene, xylene) or POLs (petroleum, oil, lubricants), and in fact, no nonhalogen containing chemical has been identified which induces a measurable response. This instrument, the RCL MONITOR, was designed to analyze individual samples or monitor an area with automated repetitive analyses. Vapor levels between 0 and 500 ppm can be determined in 90 s with a lower detection limit of 0.2 ppm using the hand-portable instrument. In addition to the development of the RCL MONITOR, advanced sampler systems are being developed to: (1) extend the dynamic range of the instrument through autodilution of the vapor and (2) allow chemical analyses to be performed on groundwater with a unique closed-loop sampler. When interfaced to the samplers, the RCL MONITOR is capable of measuring chlorinated solvent contamination in the vapor phase up to 5,000 ppm and in water and other condensed media from 10 to over 10,000 ppbwt. The performance of RCL MONITOR was demonstrated at several DOE facilities and applications have been identified in which the selective and sensitive measurement and monitoring of chlorinated hydrocarbons is essential. Case studies are currently underway at DOE Hanford and the Idaho National Engineering Laboratory

  13. Oxidation of diclofenac by aqueous chlorine dioxide: identification of major disinfection byproducts and toxicity evaluation.

    Science.gov (United States)

    Wang, Yingling; Liu, Haijin; Liu, Guoguang; Xie, Youhai

    2014-03-01

    Diclofenac (DCF), a synthetic non-steroidal anti-inflammatory drug, is one of the most frequently detected pharmaceuticals in the aquatic environment. In this work, the mechanism and toxicity of DCF degradation by ClO2 under simulated water disinfection conditions were investigated. Experimental results indicate that rapid and significant oxidation of DCF occurred within the first few minutes; however, its mineralization process was longer than its degradation process. UPLC-MS and (1)H NMR spectroscopy were performed to identify major disinfection byproducts that were generated in three tentative degradation routes. The two main routes were based on initial decarboxylation of DCF on the aliphatic chain and hydroxylation of the phenylacetic acid moiety at the C-4 position. Subsequently, the formed aldehyde intermediates were the starting point for further multistep degradation involving decarboxylation, hydroxylation, and oxidation reactions of CN bond cleavage. The third route was based on transient preservation of chlorinated derivatives resulting from electrophilic attack by chlorine on the aromatic ring, which similarly underwent CN bond cleavage. Microtox bioassay was employed to evaluate the cytotoxicity of solutions treated by ClO2. The formation of more toxic mid-byproducts during the ClO2 disinfection process poses a potential risk to consumers.

  14. Natural solar photolysis of total organic chlorine, bromine and iodine in water.

    Science.gov (United States)

    Abusallout, Ibrahim; Hua, Guanghui

    2016-04-01

    Municipal wastewater has been increasingly used to augment drinking water supplies due to the growing water scarcity. Wastewater-derived disinfection byproducts (DBPs) may negatively affect the aquatic ecosystems and human health of downstream communities during water reuse. The objective of this research was to determine the degradation kinetics of total organic chlorine (TOCl), bromine (TOBr) and iodine (TOI) in water by natural sunlight irradiation. Outdoor solar photolysis experiments were performed to investigate photolytic degradation of the total organic halogen (TOX) formed by fulvic acid and real water and wastewater samples. The results showed that TOX degradation by sunlight irradiation followed the first-order kinetics with half-lives in the range of 2.6-10.7 h for different TOX compounds produced by fulvic acid. The TOX degradation rates were generally in the order of TOI > TOBr ≅ TOCl(NH2Cl) > TOCl(Cl2). High molecular weight TOX was more susceptible to solar photolysis than corresponding low molecular weight halogenated compounds. The nitrate and sulfite induced indirect TOX photolysis rates were less than 50% of the direct photolysis rates under the conditions of this study. Fulvic acid and turbidity in water reduced TOX photodegradation. These results contribute to a better understanding of the fate of chlorinated, brominated and iodinated DBPs in surface waters.

  15. Blends of caprolactam/caprolactone copolymers and chlorinated polymers

    NARCIS (Netherlands)

    Alberda van Ekenstein, G.O.R.; Deuring, H.; ten Brinke, G.; Ellis, T.S.

    1997-01-01

    The phase behaviour of blends of chlorinated polyethylene, polyvinyl chloride (PVC) and chlorinated PVC with random copolymers of caprolactone and caprolactam has been investigated and the results correlated with a binary interaction model. The known miscibility of polycaprolactone in the chlorinate

  16. Chlorine Gas: An Evolving Hazardous Material Threat and Unconventional Weapon

    Directory of Open Access Journals (Sweden)

    Jones, Robert MD

    2010-05-01

    Full Text Available Chlorine gas represents a hazardous material threat from industrial accidents and as a terrorist weapon. This review will summarize recent events involving chlorine disasters and its use by terrorists, discuss pre-hospital considerations and suggest strategies for the initial management for acute chlorine exposure events. [West J Emerg Med. 2010; 11(2:151-156.

  17. Evaluation of trichloroethylene degradation by starch supported Fe/Ni nanoparticles via response surface methodology.

    Science.gov (United States)

    Nikroo, Razieh; Alemzadeh, Iran; Vossoughi, Manouchehr; Haddadian, Kamran

    2016-01-01

    In this study, degradation of trichloroethylene (TCE), a chlorinated hydrocarbon, using starch supported Fe/Ni nanoparticles was investigated. The scanning electron microscope images showed applying water soluble starch as a stabilizer for the Fe/Ni nanoparticles tended to reduce agglomeration and discrete particle. Also the mean particle diameter reduced from about 70 nm (unsupported Fe/Ni nanoparticle) to about 30 nm. Effects of three key independent operating parameters including initial TCE concentration (10.0-300.0 mg L(-1)), initial pH (4.00-10.00) and Fe(0) dosage (0.10-2.00) g L(-1) on TCE dechlorination efficiency in 1 hour were analysed by employing response surface methodology (RSM). Based on a five-level three-factor central composite design, TCE removal efficiency was examined and optimized. The obtained RSM model fitted the experimental data to a second order polynomial equation. The optimum dechlorination conditions at initial TCE concentration 100.0 mg L(-1) were initial pH 5.77, Fe(0) dosage 1.67 g L(-1). At these conditions TCE removal concentration reached 94.87%, which is in close acceptance with predicted value by the RSM model. PMID:26901738

  18. Chlorination of nickel ore by gaseous chlorine in the presence of active additives

    Directory of Open Access Journals (Sweden)

    Ilić Ilija B.

    2003-01-01

    Full Text Available Paper presents a thermodynamic analysis of chemical reactions occurring during chlorination with and without additives for both nickel oxides and nickel ferrites, which are component parts of nickel ore. The experimental research investigated the influence of temperature in the range from 600 up to 1000 °C and time (up to 3 h on the chlorination degree of nickel ores with and without additives. It was found that the introduction of additives such as C, S, BaS and NaCl intensified the chlorination of nickel ore. The results can be applied and may help determine the optimal conditions for the chlorination of low-grade ferrous nickel ores.

  19. Degradation of polychlorinated biphenyls

    International Nuclear Information System (INIS)

    Polychlorinated biphenyls (PCB) are generally disposed of by incineration, an expensive and hazardous method. Moreover, in cases where the PCBs are a minor component of a nontoxic fluid, such as a dielectric fluid, incineration causes loss of the nontoxic fluid as well as the PCB. An alternative method for destroying PCBs is disclosed which is not only capable of detoxification of PCB-contaminated soils, sludges, and sediments, but can also remove PCBs from solution in a wide range of concentrations, permitting full recovery of the bulk of the solution free of PCBs. The process of the invention may be operated in a batch, continuous, or semicontinuous mode, and is advantageously used to detoxify organic liquids such as transformer oils. According to the invention, PCBs are chemically degraded by contact with a Lewis acid catalyst in a nonaqueous liquid medium, in the presence of a cation which combines with the chlorine on the PCB to form a solid chloride of the cation which will precipitate out from the liquid medium. Preferred Lewis acids are metal halides, particularly a combination of aluminum chloride and ferric chloride, and the preferred cation is potassium in the form of KOH. The Lewis acids may be supplied to the process by the adventitious corrosion of a vessel containing the PCB-contaminated matter. Experiments are described to illustrate the process of the invention. 3 figs

  20. Chlorinated organic compounds in urban river sediments

    Energy Technology Data Exchange (ETDEWEB)

    Soma, Y.; Shiraishi, H.; Inaba, K. [National Inst. of Environmental Studies, Tsukuba, Ibaraki (Japan)

    1995-12-31

    Among anthropogenic chemicals, many chlorinated organic compounds have been used as insecticides and detected frequently as contaminants in urban river sediments so far. However, the number and total amount of chemicals produced commercially and used are increasing year by year, though each amount of chemicals is not so high. New types of contaminants in the environment may be detected by the use of newly developed chemicals. Chlorinated organic compounds in the urban river sediments around Tokyo and Kyoto, large cities in Japan, were surveyed and recent trends of contaminants were studied. Contaminants of the river sediments in industrial areas had a variety, but PCB (polychlorinated biphenyls) was detected in common in industrial areas. Concentration of PCB related well to the number of factories on both sides of rivers, although the use of PCB was stopped 20 years ago. In domestic areas, Triclosan (5-chloro-2-(2,4-dichlorophenoxy)-phenol) and Triclocarban (3,4,4{prime}-trichlorocarbanilide)(both are contained in soap or shampoo for fungicides), p-dichlorobenzene (insecticides for wears) and TCEP(tris-chloroethyl phosphate) were detected. EOX(extracted organic halogen) in the sediments was 5 to 10 times of chlorinated organic compounds detected by GC/MS. Major part of organic halogen was suggested to be included in chlorinated organics formed by bleaching or sterilization.

  1. 46 CFR 151.50-31 - Chlorine.

    Science.gov (United States)

    2010-10-01

    ... desired rate of discharge, provided the air or gas is oil-free and thoroughly dried by passing it over activated aluminum oxide, silica gel, or other acceptable drying agent, and provided the supply pressure is...-resistant to chlorine in either the gas or liquid phase. Cast or malleable iron shall not be used....

  2. Chlorinated tyrosine derivatives in insect cuticle

    DEFF Research Database (Denmark)

    Andersen, Svend Olav

    2004-01-01

    , not-yet sclerotized cuticle of adult femur and tibia, the amounts increased rapidly during the first 24 h after ecdysis and more slowly during the next two weeks. Control analyses using stable isotope dilution mass spectrometry have confirmed that the chlorinated tyrosines are not artifacts formed...

  3. Field-usable portable analyzer for chlorinated organic compounds. Topical report, September 1992--May 1994

    Energy Technology Data Exchange (ETDEWEB)

    Buttner, W.J.; Williams, R.D.

    1995-05-01

    Through a U.S. DOE-funded program, an advanced chlorinated organic (RCL) vapor monitor has been built and tested in actual hazardous waste site operations. The monitor exploits the analytical capabilities of a solid-state sensor which was recently developed and has remarkable selectivity for chlorinated organic vapors at sub-parts-per-million sensitivity. The basic design goal of a user-friendly, reliable, instrument with a broad dynamic range for the selective detection of chlorinated solvent vapors was demonstrated. To date, no non-halogen-containing compound has been identified that induces a measurable response on the sensor, including commonly encountered contaminants such as BTXs (benzene, toluene, and xylenes) or POLs (petroleum, oils, lubricants). In addition to the development of the RCL MONITOR, advanced sampler systems were developed to further extend the analytical capability of this instrument, allowing chemical analyses to be performed for both vapor phase and condensed contamination. The sampling methods include fixed dilution, preconcentration, and closed-loop air stripping for condensed media. With uniform success, these different series of field tests were conducted at DOE facilities on several types of samples. Independent cost-benefit analysis has concluded that significant cost savings can be achieved using the RCL MONITOR in DOE applications. This effort provides a sound fundamental technology base for the development of advanced analytical methods that are needed by the US DOE. In addition, advanced methods for detecting chlorinated hydrocarbons that are made possible by this technology will save time, reduce costs, and improve human health and safety in restoration operations. To fully achieve all possible cost savings, continued effort is necessary to develop validated methods for the use of the RCL MONITOR. The development of methods through case studies is the theme of the Phase II effort, which is currently underway.

  4. Halogenated volatile organic compounds from the use of chlorine-bleach-containing household products.

    Science.gov (United States)

    Odabasi, Mustafa

    2008-03-01

    Sodium hypochlorite (NaOCl) and many organic chemicals contained in household cleaning products may react to generate halogenated volatile organic compounds (VOCs). Halogenated VOC emissions from eight different chlorine bleach containing household products (pure and diluted) were investigated by headspace experiments. Chloroform and carbon tetrachloride were the leading compounds along with several halogenated compounds in the headspace of chlorine bleach products. One of the most surprising results was the presence of carbon tetrachloride (a probable human carcinogen and a powerful greenhouse gas that was banned for household use by the U.S. Food and Drug Administration) in very high concentrations (up to 101 mg m(-3)). By mixing surfactants or soap with NaOCl, it was shown that the formation of carbon tetrachloride and several other halogenated VOCs is possible. In addition to quantitatively determined halogenated VOCs (n = 15), several nitrogen-containing (n = 4), chlorinated (n = 10), oxygenated compounds (n = 22), and hydrocarbons (n = 14) were identified in the headspace of bleach products. Among these, 1,1-dichlorobutane and 2-chloro-2-nitropropane were the most abundant chlorinated VOCs, whereas trichloronitromethane and hexachloroethane were the most frequently detected ones. Indoor air halogenated VOC concentrations resulting from the use of four selected household products were also measured before, during, and 30 min after bathroom, kitchen, and floor cleaning applications. Chloroform (2.9-24.6 microg m(-3)) and carbon tetrachloride (0.25-459 microg m(-3)) concentrations significantly increased during the use of bleach containing products. During/ before concentration ratios ranged between 8 and 52 (25 +/- 14, average +/- SD) for chloroform and 1-1170 (146 +/- 367, average +/- SD) for carbon tetrachloride, respectively. These results indicated that the bleach use can be important in terms of inhalation exposure to carbon tetrachloride, chloroform and

  5. Cellular Response of the Amoeba Acanthamoeba castellanii to Chlorine, Chlorine Dioxide, and Monochloramine Treatments ▿

    OpenAIRE

    Mogoa, Emerancienne; Bodet, Charles; Morel, Franck; Rodier, Marie-Hélène; Legube, Bernard; Héchard, Yann

    2011-01-01

    Acanthamoeba castellanii is a free-living amoebae commonly found in water systems. Free-living amoebae might be pathogenic but are also known to bear phagocytosis-resistant bacteria, protecting these bacteria from water treatments. The mode of action of these treatments is poorly understood, particularly on amoebae. It is important to examine the action of these treatments on amoebae in order to improve them. The cellular response to chlorine, chlorine dioxide, and monochloramine was tested o...

  6. Anaerobic biodegradability and toxicity of wastewaters from chlorine and total chlorine-free bleaching of eucalyptus kraft pulps.

    NARCIS (Netherlands)

    Vidal, G.; Soto, M.; Field, J.; Mendez-Pampin, R.; Lema, J.M.

    1997-01-01

    Chlorine bleaching effluents are problematic for anaerobic wastewater treatment due to their high methanogenic toxicity and low biodegradability. Presently, alternative bleaching processes are being introduced, such as elemental chlorine-free (ECF) and total chlorine-free (TCF) bleaching. The methan

  7. Theory and application of landfarming to remediate polycyclic aromatic hydrocarbons and mineral oil-contaminated sediments: beneficial reuse

    NARCIS (Netherlands)

    Harmsen, J.; Rulkens, W.H.; Sims, R.C.; Rijtema, P.E.; Zweers, A.J.

    2007-01-01

    When applying landfarming for the remediation of contaminated soil and sediment, a fraction of the soil-bound contaminant is rapidly degraded; however, a residual concentration may remain, which slowly degrades. Degradation of polycyclic aromatic hydrocarbons (PAHs) and mineral oil can be described

  8. HYDROCARBONS DIAGNOSTIC OF POLLUTED SOILS

    Directory of Open Access Journals (Sweden)

    Mohamed Arad

    2010-12-01

    Full Text Available Petroleum hydrocarbons are known as carcinogenic and may contaminate the environment (water, air and soil. In this study, a diagnostic of polluted soils by petroleum hydrocarbons is carried out in order to know the effect of their accumulation as well as their behavior in time. The aging factor, a source of significant changing in hydrocarbon behavior, is integrated on two sites of an industrial refinery as experimental samples. The first site is recently polluted by hydrocarbons while the second is a previously polluted site.The results indicate that the concentration of hydrocarbons on the surface of the first site is greater and remains stable in time, as for the second site, hydrocarbons concentration on the surface is also important and undergoes a weak reduction. At a depth of one meter hydrocarbons exist at a greater concentration. This shows that obstinate hydrocarbons are an environmental danger for fauna and flora.

  9. Halogenase-Inspired Oxidative Chlorination Using Flavin Photocatalysis.

    Science.gov (United States)

    Hering, Thea; Mühldorf, Bernd; Wolf, Robert; König, Burkhard

    2016-04-18

    Chlorine gas or electropositive chlorine reagents are used to prepare chlorinated aromatic compounds, which are found in pharmaceuticals, agrochemicals, and polymers, and serve as synthetic precursors for metal-catalyzed cross-couplings. Nature chlorinates with chloride anions, FAD-dependent halogenases, and O2 as the oxidant. A photocatalytic oxidative chlorination is described based on the organic dye riboflavin tetraacetate mimicking the enzymatic process. The chemical process allows within the suitable arene redox potential window a broader substrate scope compared to the specific activation in the enzymatic binding pocket.

  10. HYDROCARBONS DIAGNOSTIC OF POLLUTED SOILS

    OpenAIRE

    Mohamed Arad; Abdelkader Anouzla; Mohamed Safi; Salah Souabi; Hicham Rhbal

    2010-01-01

    Petroleum hydrocarbons are known as carcinogenic and may contaminate the environment (water, air and soil). In this study, a diagnostic of polluted soils by petroleum hydrocarbons is carried out in order to know the effect of their accumulation as well as their behavior in time. The aging factor, a source of significant changing in hydrocarbon behavior, is integrated on two sites of an industrial refinery as experimental samples. The first site is recently polluted by hydrocarbons while the s...

  11. Selecting hydrocarbon rocket propulsion technology

    Science.gov (United States)

    Martin, J. A.

    1986-01-01

    Past studies have shown that the dry weight of future earth-to-orbit vehicles can be reduced by the combined use of hydrogen and hydrocarbon propulsion compared to all-hydrogen propulsion. This paper shows that the use of certain hydrocarbon engines with hydrogen engines produces the lowest vehicle dry mass. These hydrocarbon engines use propane or RP-1 fuel, hydrogen cooling, and hydrogen-rich gas generators. Integration of the hydrogen and hydrocarbon nozzles is also beneficial.

  12. Integrative approach to delineate natural attenuation of chlorinated benzenes in anoxic aquifers.

    Science.gov (United States)

    Stelzer, Nicole; Imfeld, Gwenaël; Thullner, Martin; Lehmann, Jürgen; Poser, Alexander; Richnow, Hans-H; Nijenhuis, Ivonne

    2009-06-01

    Biodegradation of chlorobenzenes was assessed at an anoxic aquifer by combining hydrogeochemistry and stable isotope analyses. In situ microcosm analysis evidenced microbial assimilation of chlorobenzene (MCB) derived carbon and laboratory investigations asserted mineralization of MCB at low rates. Sequential dehalogenation of chlorinated benzenes may affect the isotope signature of single chlorobenzene species due to simultaneous depletion and enrichment of (13)C, which complicates the evaluation of degradation. Therefore, the compound-specific isotope analysis was interpreted based on an isotope balance. The enrichment of the cumulative isotope composition of all chlorobenzenes indicated in situ biodegradation. Additionally, the relationship between hydrogeochemistry and degradation activity was investigated by principal component analysis underlining variable hydrogeochemical conditions associated with degradation activity at the plume scale. Although the complexity of the field site did not allow straightforward assessment of natural attenuation processes, the application of an integrative approach appeared relevant to characterize the in situ biodegradation potential. PMID:19250727

  13. Electrokinetically Enhanced Delivery for ERD Remediation of Chlorinated Ethenes in a Fractured Limestone Aquifer

    DEFF Research Database (Denmark)

    Broholm, Mette Martina; Hansen, Bente H.; With Nedergaard, Lærke;

    Leakage of the chlorinated solvents PCE and TCE into limestone aquifers from contaminated overburden and the long-lasting back diffusion from the secondary source in the limestone matrix pose a severe risk for contamination of drinking water resources. Dechlorination of PCE and TCE in limestone...... often accumulates cis-DCE due to incomplete dechlorination in the limestone aquifers, as observed downgradient of a PCE and TCE DNAPL source area at Naverland in Denmark. A microcosm study with limestone core material and groundwater from the Naverland site source area spiked with PCE showed...... that enhanced reductive dechlorination (ERD) by the addition of donor and specific degraders (KB1® culture) can lead to complete dechlorination of PCE and TCE in the limestone aquifer, provided sufficient contact between specific degraders, donor and specific degraders, is obtained. Advection-based delivery...

  14. Toxic effects of chlorinated cake flour in rats.

    Science.gov (United States)

    Cunningham, H M; Lawrence, G A; Tryphonas, L

    1977-05-01

    Four experiments were conducted using weanling Wistar rats to determine whether chlorinated cake flour or its constituents were toxic. Levels of 0.2 and 1.0% chlorine added to unbleached cake flour significantly (p less than 0.01) reduced growth rate by 20.7 and 85.2% and increased liver weight relative to body weight by 16.7 and 25.3%, respectively. Lipids extracted from flour chlorinated at the same levels had similar effects. Rat chow diets containing 0.2 and 0.6% chlorine in the form of chlorinated wheat gluten reduced growth rate and increased liver weight as a percentage of body weight. A rat chow diet containing 0.2% chlorine as chlorinated flour lipids increased absolute liver weight by 40%, kidney by 20%, and heart by 10% compared to pair-fed controls. PMID:864787

  15. Relation between chlorine with the quality of crude water

    International Nuclear Information System (INIS)

    Chlorine as disinfection agent in drinking water was used widely since it was successfully been practiced in drinking water in Jersey City, 1908. Mostly, water treatment plants in Malaysia were using chlorine as disinfection agent to kill pathogen and contaminated materials that can be dangerous to consumer. Because of chlorine was a strongly disinfection agent, it also can react with another chemical components such as manganese, hydrogen, sulfides, ammonia and phenol in water. These reactions happen very fast, and chlorine will not react as disinfection agent unless all the organic and inorganic substitution presented in water reacts with chlorine. These reactions between components will increase demand of chlorine in water. The demand of chlorine in water must be filled before the free radical chlorine occurred. These free radical chlorine will decay into hypochlorous acid and hypochlorite ion that so important in disinfection process to kill pathogens and pollutants in water. Most of water treatment plant to maintain free chlorine up to 0.2 mg/ L in distribution system to consumer. These researches involved determination of parameters that can be trusted to react with the chlorine in nine sampling station along Semenyih River and four stations in water treatment plants. These parameters were determined from ammonia, cyanides, sulfides, phenol, phosphorus, nitrite, manganese, iron and sum of organic carbons. Overall, these researches concluded that ammonia and sum of organic carbons were the most compounds that react with the chlorine to produce tryhalometane and chloramines. Besides that, the concentration of cyanides compounds, sulfide, phenol, phosphorus, nitrite, manganese and iron also decrease after the chlorination process. Results can used to evaluate demanding levels of chlorine in Semenyih River. (author)

  16. Apparatus and methods for hydrocarbon extraction

    Energy Technology Data Exchange (ETDEWEB)

    Bohnert, George W.; Verhulst, Galen G.

    2016-04-26

    Systems and methods for hydrocarbon extraction from hydrocarbon-containing material. Such systems and methods relate to extracting hydrocarbon from hydrocarbon-containing material employing a non-aqueous extractant. Additionally, such systems and methods relate to recovering and reusing non-aqueous extractant employed for extracting hydrocarbon from hydrocarbon-containing material.

  17. An evaluation method of hydrocarbon generating potential of highly mature and over-mature marine carbonate

    Institute of Scientific and Technical Information of China (English)

    程克明; 王兆云

    1997-01-01

    How to restore the residual organic carbon and residual hydrocarbon-generating potential is discussed based on the hydrocarbon degradability of source rock. The results indicate there is linear function relationship between the restoring coefficient of residual organic carbon (Kc) and the vitrinite reflectance (Ro% ) of various kinds of source rock, but the relationship is secondary functional between the restoring coefficient of residual hydrocarbon-generating potential (Ks) and the vitrinite reflectance (R0%). It is pointed out that Kc= (1 - Dresidual)/(1-Dprimary), Xs=Kc (Dprimary/Dresidual). The restoration of residual organic carbon and hydrocarbon-gen era ting potential of the Cambrian and Ordovician highly mature marine carbonate in the Tarim Basin and North China region shows that the lower limit value of hydrocarbon generating potential and the organic matter abundance of carbonate source rock are basically the same as that of clastic rock. The technical difficulty in hydrocarbon generating eva

  18. Antiradiation effectiveness of the chlorine C

    International Nuclear Information System (INIS)

    At present ever more attention of the experimenters in the field of search of high-effective antiray means - is directed to development of preparations from bio-active substances of a natural origin. In this connection all greater interest is caused by researches of antiray activity of these compounds, distinguished, as a rule, from known preparations of synthetic manufacture of low toxicity, absence of expressed collateral effects and possibility of course application. It has biological (antiray) activity in dozes 5-10 mg/kg and chlorine C which is derivative of chlorophil A. At present it passes tests in oncology. Porphyrines (synthetic and natural) are recently subjected to wide study as potential medicinal means, due to their ability to be accumulated in bodies of the reticulo-endothelial system and proliferous tissues, as well as their physical-chemical characteristics (fluorescence, photosensitizing action, colouring). All this testifies for the benefit of perspective use of porphyrin for treatment and diagnostics of tumors. According to the above described properties of porphyrines there is that fact, that for some of them radioprotective properties are revealed during the injections as well as before and after radiation treatment. The above said has formed the basis for study of antiray properties of the chlorine C during the experiments on small-sized laboratory animals. Antiradiation effectivity of chlorine C was studied on the mice (CBA x C57 B1) F1. Chlorine C was applied in a wide range of dozes with its' use in 3 variants: before radiation treatment, after radiation treatment, combined (before and after radiation treatment). Radioprotective activity of chlorine C reduces at an increase of a time of the injection before radiation treatment and at other ways of injection (intramuscularly, subcutaneously, per os). Studies of medical activity of chlorine C in experiments on mice have shown, that the compound does not possess medical activity. The death of

  19. Oxidative elimination of cyanotoxins: comparison of ozone, chlorine, chlorine dioxide and permanganate.

    Science.gov (United States)

    Rodríguez, Eva; Onstad, Gretchen D; Kull, Tomas P J; Metcalf, James S; Acero, Juan L; von Gunten, Urs

    2007-08-01

    As the World Health Organization (WHO) progresses with provisional Drinking Water Guidelines of 1 microg/L for microcystin-LR and a proposed Guideline of 1 microg/L for cylindrospermopsin, efficient treatment strategies are needed to prevent cyanotoxins such as these from reaching consumers. A kinetic database has been compiled for the oxidative treatment of three cyanotoxins: microcystin-LR (MC-LR), cylindrospermopsin (CYN), and anatoxin-a (ANTX) with ozone, chlorine, chlorine dioxide and permanganate. This kinetic database contains rate constants not previously reported and determined in the present work (e.g. for permanganate oxidation of ANTX and chlorine dioxide oxidation of CYN and ANTX), together with previously published rate constants for the remaining oxidation processes. Second-order rate constants measured in pure aqueous solutions of these toxins could be used in a kinetic model to predict the toxin oxidation efficiency of ozone, chlorine, chlorine dioxide and permanganate when applied to natural waters. Oxidants were applied to water from a eutrophic Swiss lake (Lake Greifensee) in static-dose testing and dynamic time-resolved experiments to confirm predictions from the kinetic database, and to investigate the effects of a natural matrix on toxin oxidation and by-product formation. Overall, permanganate can effectively oxidize ANTX and MC-LR, while chlorine will oxidize CYN and MC-LR and ozone is capable of oxidizing all three toxins with the highest rate. The formation of trihalomethanes (THMs) in the treated water may be a restriction to the application of sufficiently high-chlorine doses.

  20. Microbial PAH-Degradation in Soil: Degradation Pathways and Contributing Factors

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xu-Xiang; CHENG Shu-Pei; ZHU Cheng-Jun; SUN Shi-Lei

    2006-01-01

    Adverse effects on the environment and high persistence in the microbial degradation and environmental fate of polycyclic aromatic hydrocarbons (PAHs) are motivating interest. Many soil microorganisms can degrade PAHs and use various metabolic pathways to do so. However, both the physio-chemical characteristics of compounds as well as the physical, chemical, and biological properties of soils can drastically influence the degradation capacity of naturally occurring microorganisms for field bioremediation. Modern biological techniques have been widely used to promote the efficiency of microbial PAH-degradation and make the biodegradation metabolic pathways more clear. In this review microbial degradation of PAHs in soil is discussed, with emphasis placed on the main degradation pathways and the environmental factors affecting biodegradation.

  1. BIOREMEDIATION - TECHNOLOGY FOR DECONTAMINATION OF SOILS POLLUTED WITH PETROLEUM HYDROCARBONS

    Directory of Open Access Journals (Sweden)

    Irina-Ramona PECINGINĂ

    2013-05-01

    Full Text Available The pollution of soil with petroleum hydrocarbons prevents unfolding processes ofwater infiltration in soil, its circulation and the exchanges of the gaseous substances with theatmosphere. The biodegradation speed of the pollutants by the microorganisms is influenced ofsome factors: nutrients, soil type, humidity, temperature, pH, the type and the metabolism of themicroorganisms. The spill of the crude oil in the soil results in numerical growth of bacteriapopulations, with a concomitant reduction in their diversity, respectively with the predominantspecies that degrade hydrocarbons to simpler compounds, determining their gradualdisappearance.

  2. Comparative efficacy of chlorine and chlorine dioxide regimes for condenser slime control in seawater cooled heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Murthy, P.S.; Veeramani, P.; Ershath, M.; Rajamohan, R.; Harinath, Y.V.; Mohan, T.V.K.; Venugopalan, V.P. [BARC Facilities, Water and Steam Chemistry Div., Kalpakkam, Tamil nadu (India)

    2010-07-01

    Chlorination has long been used as an effective and economic biocide for biofouling control in seawater cooling systems. However, the efficacy of chlorine is reduced in the presence of organic content of seawater and the inability of chlorine to effectively penetrate biofilms. Chlorine dioxide is being projected as a possible alternative to chlorine. Experiments were carried out with the help of a seawater circulating facility, in which direct comparison of the efficacy of the two biocides was possible using test condenser tube assemblies. The test condenser tubes made of titanium, SS 316L and Cu-Ni 90/10 were dosed with chlorine and chlorine dioxide. Each dose was evaluated for 30 days. Continuous and intermittent additions of chlorine (0.38 - 0.45 mg L{sup -1} TRO) and chlorine dioxide (0.4 - 0.5 mg L{sup -1}) were used, along with control. The flow velocity in the tubes was maintained at 1.5 m/s. Results of the study showed that the efficacy of the biocide to control biofilms depended on the biocide and the material. Continuous chlorination resulted in 75% reduction of viable counts on titanium, followed by 24% reduction on CuNi and 6% reduction on SS 316L surfaces, as compared to the control. When compared to continuous chlorination, increase in bacterial density in the tubes was observed at different regimes of intermittent chlorination. On SS 316L and Cu-Ni surfaces, intermittent chlorination for 1h, once every 3 h, appeared to give adequate protection. Continuous addition of chlorine dioxide resulted in 99% reduction of viable counts on titanium surfaces, followed by 28% reduction on SS 316 L surfaces and 52% reduction on Cu-Ni surfaces, as compared to the controls. The data indicate that the efficacy of biocides to control biofilms depend on not only the biocide and its frequency of application but also the material of construction. (author)

  3. Comparative efficacy of chlorine and chlorine dioxide regimes for condenser slime control in seawater cooled heat exchangers

    International Nuclear Information System (INIS)

    Chlorination has long been used as an effective and economic biocide for biofouling control in seawater cooling systems. However, the efficacy of chlorine is reduced in the presence of organic content of seawater and the inability of chlorine to effectively penetrate biofilms. Chlorine dioxide is being projected as a possible alternative to chlorine. Experiments were carried out with the help of a seawater circulating facility, in which direct comparison of the efficacy of the two biocides was possible using test condenser tube assemblies. The test condenser tubes made of titanium, SS 316L and Cu-Ni 90/10 were dosed with chlorine and chlorine dioxide. Each dose was evaluated for 30 days. Continuous and intermittent additions of chlorine (0.38 - 0.45 mg L-1 TRO) and chlorine dioxide (0.4 - 0.5 mg L-1) were used, along with control. The flow velocity in the tubes was maintained at 1.5 m/s. Results of the study showed that the efficacy of the biocide to control biofilms depended on the biocide and the material. Continuous chlorination resulted in 75% reduction of viable counts on titanium, followed by 24% reduction on CuNi and 6% reduction on SS 316L surfaces, as compared to the control. When compared to continuous chlorination, increase in bacterial density in the tubes was observed at different regimes of intermittent chlorination. On SS 316L and Cu-Ni surfaces, intermittent chlorination for 1h, once every 3 h, appeared to give adequate protection. Continuous addition of chlorine dioxide resulted in 99% reduction of viable counts on titanium surfaces, followed by 28% reduction on SS 316 L surfaces and 52% reduction on Cu-Ni surfaces, as compared to the controls. The data indicate that the efficacy of biocides to control biofilms depend on not only the biocide and its frequency of application but also the material of construction. (author)

  4. Superconductivity in aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Kubozono, Yoshihiro, E-mail: kubozono@cc.okayama-u.ac.jp [Research Laboratory for Surface Science, Okayama University, Okayama 700-8530 (Japan); Research Center of New Functional Materials for Energy Production, Storage and Transport, Okayama University, Okayama 700-8530 (Japan); Japan Science and Technology Agency, ACT-C, Kawaguchi 332-0012 (Japan); Goto, Hidenori; Jabuchi, Taihei [Research Laboratory for Surface Science, Okayama University, Okayama 700-8530 (Japan); Yokoya, Takayoshi [Research Laboratory for Surface Science, Okayama University, Okayama 700-8530 (Japan); Research Center of New Functional Materials for Energy Production, Storage and Transport, Okayama University, Okayama 700-8530 (Japan); Kambe, Takashi [Department of Physics, Okayama University, Okayama 700-8530 (Japan); Sakai, Yusuke; Izumi, Masanari; Zheng, Lu; Hamao, Shino; Nguyen, Huyen L.T. [Research Laboratory for Surface Science, Okayama University, Okayama 700-8530 (Japan); Sakata, Masafumi; Kagayama, Tomoko; Shimizu, Katsuya [Center of Science and Technology under Extreme Conditions, Osaka University, Osaka 560-8531 (Japan)

    2015-07-15

    Highlights: • Aromatic superconductor is one of core research subjects in superconductivity. Superconductivity is observed in certain metal-doped aromatic hydrocarbons. Some serious problems to be solved exist for future advancement of the research. This article shows the present status of aromatic superconductors. - Abstract: ‘Aromatic hydrocarbon’ implies an organic molecule that satisfies the (4n + 2) π-electron rule and consists of benzene rings. Doping solid aromatic hydrocarbons with metals provides the superconductivity. The first discovery of such superconductivity was made for K-doped picene (K{sub x}picene, five benzene rings). Its superconducting transition temperatures (T{sub c}’s) were 7 and 18 K. Recently, we found a new superconducting K{sub x}picene phase with a T{sub c} as high as 14 K, so we now know that K{sub x}picene possesses multiple superconducting phases. Besides K{sub x}picene, we discovered new superconductors such as Rb{sub x}picene and Ca{sub x}picene. A most serious problem is that the shielding fraction is ⩽15% for K{sub x}picene and Rb{sub x}picene, and it is often ∼1% for other superconductors. Such low shielding fractions have made it difficult to determine the crystal structures of superconducting phases. Nevertheless, many research groups have expended a great deal of effort to make high quality hydrocarbon superconductors in the five years since the discovery of hydrocarbon superconductivity. At the present stage, superconductivity is observed in certain metal-doped aromatic hydrocarbons (picene, phenanthrene and dibenzopentacene), but the shielding fraction remains stubbornly low. The highest priority research area is to prepare aromatic superconductors with a high superconducting volume-fraction. Despite these difficulties, aromatic superconductivity is still a core research target and presents interesting and potentially breakthrough challenges, such as the positive pressure dependence of T{sub c} that is clearly

  5. Revisiting the thermochemistry of chlorine fluorides

    CERN Document Server

    Sánchez, H R

    2016-01-01

    In this work, accurate calculations of standard enthalpies of formation of chlorine fluorides (ClF$_n$, n=1--7; Cl$_2$F and Cl$_3$F$_2$) were performed through the isodesmic reactions scheme. It is argued that, for many chlorine fluorides, the gold standard method of quantum chemistry (CCSD(T)) is not capable to predict enthalpy values nearing chemical accuracy if atomization scheme is used. This is underpinned by a thorough analysis of total atomization energy results and the inspection of multireference features of these compounds. Other thermodynamic quantities were also calculated at different temperatures. In order to complement the energetic description, elimination curves were studied through density functional theory as a computationally affordable alternative to highly correlated wave function-based methods.

  6. Bacterial responses to reactive chlorine species.

    Science.gov (United States)

    Gray, Michael J; Wholey, Wei-Yun; Jakob, Ursula

    2013-01-01

    Hypochlorous acid (HOCl), the active ingredient of household bleach, is the most common disinfectant in medical, industrial, and domestic use and plays an important role in microbial killing in the innate immune system. Given the critical importance of the antimicrobial properties of chlorine to public health, it is surprising how little is known about the ways in which bacteria sense and respond to reactive chlorine species (RCS). Although the literature on bacterial responses to reactive oxygen species (ROS) is enormous, work addressing bacterial responses to RCS has begun only recently. Transcriptomic and proteomic studies now provide new insights into how bacteria mount defenses against this important class of antimicrobial compounds. In this review, we summarize the current knowledge, emphasizing the overlaps between RCS stress responses and other more well-characterized bacterial defense systems, and identify outstanding questions that represent productive avenues for future research. PMID:23768204

  7. Recent Achievements in the Radiation-Catalysed Chlorination of Chlorinated Pentane Derivatives

    International Nuclear Information System (INIS)

    The radiation-catalysed chlorination of the so-called tetrachloro-cyclopentane, the product obtained from cyclopentadiene by addition of chlorine, has already been studied earlier by the authors with success. On maintaining an adequate dosage rate, no ring cleavage occurs, and, mainly for stereochemical reasons, octachloro-cyclopentene forms as an end product - similarly to conventional chlorination carried out at high temperature (400-500oC), but at substantially lower temperature (170oC) and without any resin formation. It is known that besides other end products, octachloro-cyclopentene forms also from perchlorinated pentane, under simultaneous cyclization. In their recent experiments presented here, the authors investigated how and to what extent the yield of octachloro-cyclopentene is affected by additional chlorination of pentane, previously chlorinated under cooling (at 10 to 30oC). The experiments were carried out with a Co60 radiation source of 330 c at a dosage rate of 8 x 103 to 8 x 104r/hr, in a heated reaction mixture, mixed with a chlorine stream for periods not exceeding 30 hr. It was found that also this type of chlorination and cyclization takes place at a temperature substantially lower than the conventional 500-600oC. According to the experiments, in this case it is advisable to raise the initial temperature of 170oC of the reaction gradually to 220oC with the progress of the reaction, in order to promote the cyclization reaction. It was found, namely, that first the paraffin chain was further chlorinated and later the perchlorinated pentane derivatives cyclize partly to octachloro-cyclopentene, under formation of other chlorinated alkane and alkene derivatives. This reaction mechanism was also supported by thermodynamical calculations. The end product contains three main components; its content of octachloro-cyclopentene ranges between 25 and 35%. The data required for the evaluation of the economy of the method will be available only on the

  8. Emerging nitrogenous disinfection byproducts: Transformation of the antidiabetic drug metformin during chlorine disinfection of water.

    Science.gov (United States)

    Armbruster, Dominic; Happel, Oliver; Scheurer, Marco; Harms, Klaus; Schmidt, Torsten C; Brauch, Heinz-Jürgen

    2015-08-01

    As an environmental contaminant of anthropogenic origin metformin is present in the high ng/L- up to the low μg/L-range in most surface waters. Residues of metformin may lead to the formation of disinfection by-products during chlorine disinfection, when these waters are used for drinking water production. Investigations on the underlying chemical processes occurring during treatment of metformin with sodium hypochlorite in aqueous medium led to the discovery of two hitherto unknown transformation products. Both substances were isolated and characterized by HPLC-DAD, GC-MS, HPLC-ESI-TOF, (1)H-NMR and single-crystal X-ray structure determination. The immediate major chlorination product is a cyclic dehydro-1,2,4-triazole-derivate of intense yellow color (Y; C4H6ClN5). It is a solid chlorimine of limited stability. Rapid formation was observed between 10 °C and 30 °C, as well as between pH 3 and pH 11, in both ultrapure and tap water, even at trace quantities of reactants (ng/L-range for metformin, mg/L-range for free chlorine). While Y is degraded within a few hours to days in the presence of light, elevated temperature, organic solvents and matrix constituents within tap water, a secondary degradation product was discovered, which is stable and colorless (C; C4H6ClN3). This chloroorganic nitrile has a low photolysis rate in ambient day light, while being resistant to heat and not readily degraded in the presence of organic solvents or in the tap water matrix. In addition, the formation of ammonia, dimethylamine and N,N-dimethylguanidine was verified by cation exchange chromatography.

  9. Chlorine diffusion in CdTe

    Energy Technology Data Exchange (ETDEWEB)

    Sadaiyandi, K.; Ramachandran, K. (School of Physics, Madurai Kamaraj Univ. (India))

    1991-06-01

    The experimental results of chlorine diffusion in CdTe reveal that the dominant mechanism for diffusion is through neutral defect pair such as (V{sub Cd}V{sub Te}){sup *}. Here, theoretical calculations are carried out for all the possible mechanisms such as single vacancy, single interstitial, neutral defect pair, and Frenkel defect pair. The results suggest that the most possible mechanism for Cl diffusion in CdTe is that through neutral defect pair, supporting the experiment. (orig.).

  10. Chlorination and Carbochlorination of Cerium Oxide

    International Nuclear Information System (INIS)

    The chlorination and carbochlorination of cerium oxide were studied by thermogravimetry under controlled atmosphere (TG) in the 7000C 9500C temperature range.Both reactants and products were analyzed by X-ray diffraction (RX), scanning electronic microscopy (SEM) and energy dispersive spectroscopy (EDS). Thermodynamic calculations were performed by computer assisted software.The chlorination starts at a temperature close to 8000C.This reaction involves the simultaneous formation and evaporation of CeCl3.Both processes control the reaction rate and their kinetic may not be easily separated.The apparent chlorination activation energy in the 8500C-9500C temperature range is 172 to 5 kJ/ mole.Carbon transforms the CeO2-Cl2 into a more reactive system: CeO2-C-Cl2, where the effects of the carbon content, total flow rate and temperature were analyzed.The carbochlorination starting temperature is 7000C.This reaction is completed in one step controlled by mass transfer with an apparent activation energy of 56 to 5 kJ/mole in the 8500C-9500C temperature range

  11. Enhanced degradation of mono aromatic hydrocarbons in sandy aquifer materials

    Energy Technology Data Exchange (ETDEWEB)

    Corseuil, Henry X. [Santa Catarina Univ., Florianopolis, SC (Brazil). Dept. de Engenharia Sanitaria; Weber Junior, W.J. [Michigan Univ., Ann Arbor, MI (United States). Dept. of Civil and Environmental Engineering

    1993-12-31

    The use of an inoculation technique to enhance rates of in-situ biodegradation of toxic organic contaminants by increasing subsurface populations of specific microorganisms is described. An external biologically active carbon (BAC) adsorber is demonstrated to be an efficient reactor system for collection, acclimation and enrichment of microorganisms for the inoculation process (author). 15 refs., 3 figs.

  12. Biosynthesis of highly unsaturated fatty acids by hydrocarbon degrading microorganisms

    Directory of Open Access Journals (Sweden)

    MEHDI GHASEMI

    2015-04-01

    Full Text Available Disruption of polyunsaturated fatty acids (PUFA metabolism leads to many diseases. In this study, producers of γ-linolenic acid (GLA, arachidonic acid (ARA and eicosapentaenoic acid (EPA were selected: Cephalosporium humicola IE (on glucose, dry biomass – 14 g/l, total lipids – 18-20%, GLA in lipids – 12.0%, Mucor globosus 11 (respectively – 15 g/l, 18% and 5% and Pythium irregulare LX (on glucose, dry biomass – 14.5 g/l, total lipids – 18-20%, 9.2 and 7.8% of ARA and EPA, respectively. On crude oil as the only source of carbon, the amount of biomass of the specified fungi decreases by 3-4 times, whereas the quantity of lipids and highly unsaturated fatty acids increases in four and 1.2 - 3.4 times, respectively. The maximum γ-linolenic acid in M. globosus and C. humicola was detected at neutral рН. Optimum volume of inoculate was 2.0-4.0%, nitrogen source NH4NO3, a carbon-nitrogen ratio 34:1. For biosynthesis of ARA and EPA by P. irregulare, the optimum nitrogen source was NH4Cl, рН 7.0- 8.0 and С/N - 50:1 at 28°C. The process of adaptation to stressful situation under crude oil motivated the increase of the rate of membrane phospholipids with high quantity of unsaturated fatty acids.

  13. To what extent can isotopes help substantiate natural attenuation of chlorinated ethenes?

    DEFF Research Database (Denmark)

    Badin, A.; Broholm, Mette Martina; Hunkeler, D.

    degree to which isotopes could help