Science.gov

Sample records for pollutants biological degradation

  1. Chemotactic selection of pollutant degrading soil bacteria

    DOEpatents

    Hazen, T.C.

    1991-03-04

    A method is described for identifying soil microbial strains which may be bacterial degraders of pollutants. This method includes: Placing a concentration of a pollutant in a substantially closed container; placing the container in a sample of soil for a period of time ranging from one minute to several hours; retrieving the container and collecting its contents; microscopically determining the identity of the bacteria present. Different concentrations of the pollutant can be used to determine which bacteria respond to each concentration. The method can be used for characterizing a polluted site or for looking for naturally occurring biological degraders of the pollutant. Then bacteria identified as degraders of the pollutant and as chemotactically attracted to the pollutant are used to innoculate contaminated soil. To enhance the effect of the bacteria on the pollutant, nutrients are cyclicly provided to the bacteria then withheld to alternately build up the size of the bacterial colony or community and then allow it to degrade the pollutant.

  2. Ozonisation coupled with biological degradation for treatment of phenolic pollutants: a mechanistically based study.

    PubMed

    Amat, Ana M; Arques, Antonio; Beneyto, Higinio; García, Ana; Miranda, Miguel A; Seguí, Sergio

    2003-10-01

    Phenolic acids constitute an important group of pollutants which are reluctant to biological treatment. Solutions containing a mixture of cinnamic acid, p-coumaric acid, caffeic acid and ferulic acid were submitted to ozonisation. Then, the changes in biodegradability along the process were studied by means of respirometry. There is an optimum ozone dosage in the interval 3-5 min of treatment which allows to achieve the maximum increase in biodegradability (more than 10 times) and a high efficiency of the ozonisation process (COD decreases to a half of its initial value). Further ozonisation does not help to increase biodegradability and is clearly disadvantageous. Similar results are obtained with actual samples of olive oil wastewaters. This behaviour is explained based on the formation of highly biodegradable benzaldehydes as key ozonisation intermediates, in the early reaction stages.

  3. Biological effects and subsequent economic effects and losses from marine pollution and degradations in marine environments: Implications from the literature.

    PubMed

    Ofiara, Douglas D; Seneca, Joseph J

    2006-08-01

    This paper serves as the missing piece in a more fuller understanding about economic losses from marine pollution, and demonstrates what losses have been estimated in the literature. Biological effects from marine pollution are linked with resulting economic effects and losses. The merging of these two areas is usually absent in studies of marine pollution losses. The literature has examined several effects due to marine pollution: damages due to harvest closures-restrictions, damages from consumption of unsafe seafood, damages due to decreased recreational activity, and damages related to waterfront real estate adjacent to contaminated water. Overall, marine pollution can and has resulted in sizable economic effects and losses. On the basis of the literature there is adequate justification for public policy actions to curb marine pollution, require inspection of seafood for toxic substances, and preserve marine water quality and sensitive marine environments.

  4. Chemotactic selection of pollutant degrading soil bacteria

    DOEpatents

    Hazen, Terry C.

    1994-01-01

    A method for identifying soil microbial strains which may be bacterial degraders of pollutants comprising the steps of placing a concentration of a pollutant in a substantially closed container, placing the container in a sample of soil for a period of time ranging from one minute to several hours, retrieving the container, collecting the contents of the container, and microscopically determining the identity of the bacteria present. Different concentrations of the pollutant can be used to determine which bacteria respond to each concentration. The method can be used for characterizing a polluted site or for looking for naturally occurring biological degraders of the pollutant. Then bacteria identified as degraders of the pollutant and as chemotactically attracted to the pollutant are used to inoculate contaminated soil. To enhance the effect of the bacteria on the pollutant, nutrients are cyclicly provided to the bacteria then withheld to alternately build up the size of the bacterial colony or community and then allow it to degrade the pollutant.

  5. Biology and Water Pollution Control.

    ERIC Educational Resources Information Center

    Warren, Charles E.

    Within this text, the reader is attuned to the role biology can and should play in combating the alarming increase in water pollution. Both the urgency of the problem and the biological techniques that are being developed to cope with the water pollution crisis are scrutinized; what is and is not known about the problem is explained; past,…

  6. Biological monitoring of airborne pollution

    SciTech Connect

    Ditz, D.W. )

    1990-01-01

    Common plants such as grasses, mosses, and even goldenrod may turn out to have a new high-tech role as monitors of airborne pollution from solid waste incinerators. Certain plants that respond to specific pollutants can provide continuous surveillance of air quality over long periods of time: they are bio-indicators. Other species accumulate pollutants and can serve as sensitive indicators of pollutants and of food-chain contamination: they are bio-accumulators. Through creative use of these properties, biological monitoring can provide information that cannot be obtained by current methods such as stack testing.

  7. Biological monitors of pollution

    SciTech Connect

    Root, M.

    1990-02-01

    This article discusses the use of biological monitors to assess the biological consequences of toxicants in the environment, such as bioavailability, synergism, and bioaccumulation through the food web. Among the organisms discussed are fly larvae, worms, bees, shellfish, fishes, birds (starlings, owls, hawks, songbirds) and mammals (rabbits, field mice, shrews).

  8. Method of degrading pollutants in soil

    DOEpatents

    Hazen, T.C.; Lopez-De-Victoria, G.

    1994-07-05

    Disclosed are a method and system for enhancing the motility of microorganisms. This is accomplished by placing an effective amount of chlorinated hydrocarbons, preferably chlorinated alkenes, and most preferably trichloroethylene in spaced relation to the microbes so that the surprisingly strong, monomodal, chemotactic response of the chlorinated hydrocarbon on subsurface microbes can draw the microbes away from or towards and into a substance, as desired. In remediation of groundwater pollution, for example, TCE can be injected into the plume to increase the population of microbes at the plume whereby the plume can be more quickly degraded. A TCE-degrading microbe, such as Welchia alkenophilia, can be used to degrade the TCE following the degradation of the original pollutant. 5 figures.

  9. Method of degrading pollutants in soil

    DOEpatents

    Hazen, Terry C.; Lopez-De-Victoria, Geralyne

    1994-01-01

    A method and system for enhancing the motility of microorganisms by placing an effective amount of chlorinated hydrocarbons, preferably chlorinated alkenes, and most preferably trichloroethylene in spaced relation to the microbes so that the surprisingly strong, monomodal, chemotactic response of the chlorinated hydrocarbon on subsurface microbes can draw the microbes away from or towards and into a substance, as desired. In remediation of groundwater pollution, for example, TCE can be injected into the plume to increase the population of microbes at the plume whereby the plume can be more quickly degraded. A TCE-degrading microbe, such as Welchia alkenophilia, can be used to degrade the TCE following the degradation of the original pollutant.

  10. Photocatalytic Degradation of a Gaseous Organic Pollutant

    NASA Astrophysics Data System (ADS)

    Yu, Jimmy C.; Chan, Linda Y. L.

    1998-06-01

    A simple and effective method to demonstrate the phenomenon of photocatalytic degradation of a gaseous organic pollutant was developed. Titanium dioxide (anatase) was used as the photocatalyst, and sunlight was found to be an effective light source for the activation of TiO2. The organic pollutant degrade in this demonstration was a common indoor air pollutant, dichloromethane. The TiO2 powder was suspended in a 3:7 ethanol/water solution, and then coated on microscopic slides. The slides together with appropriate indicators were place in 250-mL conical flasks. A small amount of the volatile dichloromethane solvent was injected into each flask, and the flasks were sealed with a piece of parafilm. Some of the flasks were exposed to direct sunlight, and some were kept in the dark. The degradation products of dichloromethane were carbon dioxide, water, and hydrogen chloride. Formation of the acidic HCl gas could be monitored easily by two indicators, the universal pH paper and ammonia. The universal pH paper would change color from green to red in the presence of HCl and H2O, while HCl would react with ammonia to form a white fume. The results of this demonstration showed that both TiO2 and light were required in this photocatalytic degradation process.

  11. Sequential UV-biological degradation of chlorophenols.

    PubMed

    Tamer, Essam; Hamid, Zilouei; Aly, Amin Magdy; Ossama, El Tayeb; Bo, Mattiasson; Benoit, Guieysse

    2006-04-01

    The sequential UV-biological degradation of a mixture of 4-chlorophenol (CP), 2,4-dichlorophenol (DCP), 2,4,6-trichlorophenol (TCP), and pentachlorophenol (PCP) was first tested with each pollutant supplied at an initial concentration of 50 mg l(-1). Under these conditions, the chlorophenols were photodegraded in the following order of removal rate: PCP>TCP>DCP>CP with only CP and DCP remaining after 40 h of irradiation. The remaining CP (41 mg l(-1)) and DCP (13 mg l(-1)) were then completely removed by biological treatment with an activated sludge mixed culture. Biodegradation did not occur in similar tests conducted with a non-irradiated mixture due to the high microbial toxicity of the solution. UV treatment lead to a significant reduction of the phytotoxicity to Lipedium sativum but no further reduction of phytotoxicity was observed after biological treatment. Evidence was found that the pollutants were partially photodegraded into toxic and non-biodegradable products. When the pollutants were tested individually (initial concentration of 50 mg l(-1)), PCP, TCP, DCP, 4-CP were photodegraded according to first order kinetic model (r2>99) with half-lives of 2.2, 3.3, 5.7, and 54 h, respectively. The photoproducts were subsequently biodegraded. This study illustrates the potential of UV as pre-treatment for biological treatment in order to remove toxicity and enhance the biodegradability of organic contaminants. However, it also shows that UV treatment must be carefully optimized to avoid the formation of toxic and/or recalcitrant photoproducts and results from studies conducted on single contaminants cannot be extrapolated to mixtures.

  12. Zinc oxide tetrapods as efficient photocatalysts for organic pollutant degradation

    NASA Astrophysics Data System (ADS)

    Liu, Fangzhou; Leung, Yu Hang; Djurisić, Aleksandra B.; Liao, Changzhong; Shih, Kaimin

    2014-03-01

    Bisphenol A (BPA) and other organic pollutants from industrial wastewater have drawn increasing concern in the past decades regarding their environmental and biological risks, and hence developing strategies of effective degradation of BPA and other organic pollutants is imperative. Metal oxide nanostructures, in particular titanium oxide (TiO2) and zinc oxide (ZnO), have been demonstrated to exhibit efficient photodegradation of various common organic dyes. ZnO tetrapods are of special interest due to their low density of native defects which consequently lead to lower recombination losses and higher photocatalytic efficiency. Tetrapods can be obtained by relatively simple and low-cost vapor phase deposition in large quantity; the micron-scale size would also be advantageous for catalyst recovery. In this study, the photodegradation of BPA with ZnO tetrapods and TiO2 nanostructures under UV illumination were compared. The concentration of BPA dissolved in DI water was analyzed by high-performance liquid chromatography (HPLC) at specified time intervals. It was observed that the photocatalytic efficiency of ZnO tetrapods eventually surpassed Degussa P25 in free-standing form, and more than 80% of BPA was degraded after 60 min. Photodegradation of other organic dye pollutants by tetrapods and P25 were also examined. The superior photocatalytic efficiency of ZnO tetrapods for degradation of BPA and other organic dye pollutants and its correlation with the material properties were discussed.

  13. Biocarrier composition for and method of degrading pollutants

    DOEpatents

    Fliermans, C.B.

    1994-01-01

    The present invention relates to biocarrier compositions that attract and bond pollutant-degrading antigens that will degrade the pollutants. Biocarriers are known generally as a variety of inert or semi-inert compounds or structures having the ability to sequester (attract), hold and biomagnify (enhance) specific microorganisms within their structure. Glass or polystyrene beads are the most well known biocarriers. The biocarrier, which is preferably in the form of glass microspheres, is coated with an antibody or group of antibodies that attract and react specifically with certain pollutant-degrading antigens. The antibody, once bonded to the biocarrier, is used by the composition to attract and bond those pollutant-degrading antigens. Each antibody is specific for an antigen that is specific for a given pollutant. The resulting composition is subsequently exposed to an environment contaminated with pollutants for degradation. In the preferred use, the degrading composition is formed and then injected directly into or near a plume or source of contamination.

  14. Combined chemical-biological treatment of wastewater containing refractory pollutants.

    PubMed

    Jeworski, M; Heinzle, E

    2000-01-01

    Biological processes are usually most efficient for degrading pollutants occurring in wastewater. Refractory and toxic compounds contained limit their applicability. In such cases combinations with chemical oxidation processes may improve the overall efficiency and efficacy. Most suitable oxidation processes for combination with biological treatment are wet air oxidation, ozonation, hydrogen peroxide treatment and other advanced oxidation processes. Most effective are OH-radicals produced in all these oxidation processes. Chemical oxidation produces intermediates with usually improved biodegradability. Process combinations may be serial or with recycling between chemical oxidation and biological treatment. Design criteria, control of combined processes and recent applications are reviewed.

  15. The biological degradation of cellulose.

    PubMed

    Béguin, P; Aubert, J P

    1994-01-01

    Cellulolytic microorganisms play an important role in the biosphere by recycling cellulose, the most abundant carbohydrate produced by plants. Cellulose is a simple polymer, but it forms insoluble, crystalline microfibrils, which are highly resistant to enzymatic hydrolysis. All organisms known to degrade cellulose efficiently produce a battery of enzymes with different specificities, which act together in synergism. The study of cellulolytic enzymes at the molecular level has revealed some of the features that contribute to their activity. In spite of a considerable diversity, sequence comparisons show that the catalytic cores of cellulases belong to a restricted number of families. Within each family, available data suggest that the various enzymes share a common folding pattern, the same catalytic residues, and the same reaction mechanism, i.e. either single substitution with inversion of configuration or double substitution resulting in retention of the beta-configuration at the anomeric carbon. An increasing number of three-dimensional structures is becoming available for cellulases and xylanases belonging to different families, which will provide paradigms for molecular modeling of related enzymes. In addition to catalytic domains, many cellulolytic enzymes contain domains not involved in catalysis, but participating in substrate binding, multi-enzyme complex formation, or possibly attachment to the cell surface. Presumably, these domains assist in the degradation of crystalline cellulose by preventing the enzymes from being washed off from the surface of the substrate, by focusing hydrolysis on restricted areas in which the substrate is synergistically destabilized by multiple cutting events, and by facilitating recovery of the soluble degradation products by the cellulolytic organism. In most cellulolytic organisms, cellulase synthesis is repressed in the presence of easily metabolized, soluble carbon sources and induced in the presence of cellulose

  16. ELECTROCHEMICAL DEGRADATION OF PERSISTANCE POLLUTANTS IN GROUNDWATER AND SEDIMENTS

    EPA Science Inventory

    Electrochemical Degradation (ECD) utilizes redox potential at the anode and the cathode to oxidize and/or reduce organic contaminants. ECD of environmentally persistence pollutants such chlorinate solvents, PCBs, and PAHs, although theoretically possible, has not been experimenta...

  17. Modeling organic micro pollutant degradation kinetics during sewage sludge composting.

    PubMed

    Sadef, Yumna; Poulsen, Tjalfe Gorm; Bester, Kai

    2014-11-01

    Degradation of 13 different organic micro-pollutants in sewage sludge during aerobic composting at 5 different temperatures over a 52 day period was investigated. Adequacy of two kinetic models: a single first order, and a dual first order expression (using an early (first 7 days) and a late-time (last 45 days) degradation coefficient), for describing micro-pollutant degradation, and kinetic constant dependency on composting temperature were evaluated. The results showed that both models provide relatively good descriptions of the degradation process, with the dual first order model being most accurate. The single first order degradation coefficient was 0.025 d(-1) on average across all compounds and temperatures. At early times, degradation was about three times faster than at later times. Average values of the early and late time degradation coefficients for the dual first order model were 0.066 d(-1) and 0.022 d(-1), respectively. On average 30% of the initial micro-pollutant mass present in the compost was degraded rapidly during the early stages of the composting process. Single first order and late time dual first order kinetic constants were strongly dependent on composting temperature with maximum values at temperatures of 35-65°C. In contrast the early time degradation coefficients were relatively independent of composting temperature.

  18. Impact of compost process conditions on organic micro pollutant degradation during full scale composting.

    PubMed

    Sadef, Yumna; Poulsen, Tjalfe Gorm; Bester, Kai

    2015-06-01

    Knowledge about the effects of oxygen concentration, nutrient availability and moisture content on removal of organic micro-pollutants during aerobic composting is at present very limited. Impact of oxygen concentration, readily available nitrogen content (NH4(+), NO3(-)), and moisture content on biological transformation of 15 key organic micro-pollutants during composting, was therefore investigated using bench-scale degradation experiments based on non-sterile compost samples, collected at full-scale composting facilities. In addition, the adequacy of bench-scale composting experiments for representing full-scale composting conditions, was investigated using micro-pollutant concentration measurements from both bench- and full-scale composting experiments. Results showed that lack of oxygen generally prevented transformation of organic micro-pollutants. Increasing readily available nitrogen content from about 50 mg N per 100 g compost to about 140 mg N per 100 g compost actually reduced micro-pollutant transformation, while changes in compost moisture content from 50% to 20% by weight, only had minor influence on micro-pollutant transformation. First-order micro-pollutant degradation rates for 13 organic micro-pollutants were calculated using data from both full- and bench-scale experiments. First-order degradation coefficients for both types of experiments were similar and ranged from 0.02 to 0.03 d(-1) on average, indicating that if a proper sampling strategy is employed, bench-scale experiments can be used to represent full-scale composting conditions.

  19. Biological degradation of plastics: a comprehensive review.

    PubMed

    Shah, Aamer Ali; Hasan, Fariha; Hameed, Abdul; Ahmed, Safia

    2008-01-01

    Lack of degradability and the closing of landfill sites as well as growing water and land pollution problems have led to concern about plastics. With the excessive use of plastics and increasing pressure being placed on capacities available for plastic waste disposal, the need for biodegradable plastics and biodegradation of plastic wastes has assumed increasing importance in the last few years. Awareness of the waste problem and its impact on the environment has awakened new interest in the area of degradable polymers. The interest in environmental issues is growing and there are increasing demands to develop material which do not burden the environment significantly. Biodegradation is necessary for water-soluble or water-immiscible polymers because they eventually enter streams which can neither be recycled nor incinerated. It is important to consider the microbial degradation of natural and synthetic polymers in order to understand what is necessary for biodegradation and the mechanisms involved. This requires understanding of the interactions between materials and microorganisms and the biochemical changes involved. Widespread studies on the biodegradation of plastics have been carried out in order to overcome the environmental problems associated with synthetic plastic waste. This paper reviews the current research on the biodegradation of biodegradable and also the conventional synthetic plastics and also use of various techniques for the analysis of degradation in vitro.

  20. Dye Degradation by Fungi: An Exercise in Applied Science for Biology Students

    ERIC Educational Resources Information Center

    Lefebvre, Daniel D.; Chenaux, Peter; Edwards, Maureen

    2005-01-01

    An easily implemented practical exercise in applied science for biology students is presented that uses fungi to degrade an azo-dye. This is an example of bioremediation, the employment of living organisms to detoxify or contain pollutants. Its interdisciplinary nature widens students' perspectives of biology by exposing them to a chemical…

  1. Degradation of environmental pollutants by Trametes trogii.

    PubMed

    Haglund, C; Levín, L; Forchiassin, F; López, M; Viale, A

    2002-01-01

    The ability of the ligninolytic fungus Trametes trogii to degrade in vitro different xenobiotics (PCBs, PAHs and dyes) was evaluated. Either 200 ppm of a PCB mixture (Aroclor 1150) or 160 ppm of an industrial PAH mixture (10% V/V of PAHs, principal components hexaethylbenzene, naphthalene, 1-methyl naphthalene, acenaphthylene, anthracene, fluorene and phenanthrene), were added to trophophasic and idiophasic cultures growing in a nitrogen limited mineral medium (glucose/asparagine) and in a complex medium (malt extract/glucose). Gas-liquid chromatography proved that within 7 to 12 d more than 90% of the organopollutants added were removed. The decrease in absorbance at 620 nm demonstrated that cultures of this fungus were able to transform 80% of the dye Anthraquinone-blue (added at a concentration of 50 ppm) in 1.5 h. Enzyme estimations indicated high activity of laccase (up to 0.55 U/mL), as well as lower production of manganese-peroxidase. Laccase activity, detected in all the conditions assayed, could be implicated in the degradation of these organopollutants. Considering the results obtained, T. trogii seems promising for detoxification.

  2. Ultrasound based AOP for emerging pollutants: from degradation to mechanism.

    PubMed

    Rayaroth, Manoj P; Aravind, Usha K; Aravindakumar, Charuvila T

    2016-04-14

    Ultrasound is known to degrade organic compounds by pyrolysis and by the reaction of free radicals. In this work, sonolytic degradation of an identified water pollutant, coomassie brilliant blue (CBB), has been carried out in pure water as well as in river water. In the case of pure water, 90 % degradation was obtained after 30 min of sonication (350 kHz frequency, 60 W power), whereas in river water, the same efficiency was achieved only after 90 min. The degradation was also performed in the presence of varying concentration of (10-100 mg L(-1)) inorganic ions such as chloride, sulfate, nitrate, bicarbonate, and carbonate ions which were detected in the river water sample. Higher concentration of chloride enhanced the degradation due to the salting out mechanism. The enhancement of degradation in the presence of nitrate is mainly due to the change in the surface potential at the interface of the cavitating bubble. Bicarbonate ion and carbonate ion enhanced the degradation due to the involvement of carbonate radicals. A possible degradation mechanism is proposed based on the product profile determined by LC-Q-ToF-MS. The low efficiency of degradation in river water compared to that in pure water is likely due to the increased rate of bubble dissolution or escape of bubbles (degassing effect), and the scavenging of (•)OH by the organic content (high chemical oxygen demand (COD)).

  3. Biological pollutants and biological pollution--an increasing cause for concern.

    PubMed

    Elliott, Michael

    2003-03-01

    There are increasing concerns regarding the delivery, movement and presence of non-indigenous or invasive species into marine and estuarine areas. Such introductions can be on a large scale such as the movement to higher latitudes of species as the result of global warming. Alternatively, such species can be introduced into a marine or estuarine area as the result of small-scale events, such as the liberation from waste-water discharges, aquaculture or ballast-water discharge. However, if such introductions lead to a successful colonisation then they can become a wide-scale problem. This paper considers the introduction of such non-indigenous and invasive species as biological pollution and biological pollutants and it discusses the definitions and concepts used in assessing and managing marine pollution in relation to these terms.

  4. Bioremediation via in situ microbial degradation of organic pollutants.

    PubMed

    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.

  5. Hydroxylamine Promoted Goethite Surface Fenton Degradation of Organic Pollutants.

    PubMed

    Hou, Xiaojing; Huang, Xiaopeng; Jia, Falong; Ai, Zhihui; Zhao, Jincai; Zhang, Lizhi

    2017-03-30

    In this study, we construct a surface Fenton system with hydroxylamine (NH2OH), goethite (α-FeOOH), and H2O2 (α-FeOOH-HA/H2O2) to degrade various organic pollutants including dyes (methyl orange, methylene blue, and rhodamine B), pesticides (pentachlorophenol, alachlor, and atrazine), and antibiotics (tetracycline, chloramphenicol, and lincomycin) at pH 5.0. In this surface Fenton system, the presence of NH2OH could greatly promote the H2O2 decomposition on the α-FeOOH surface to produce •OH without releasing any detectable iron ions during the alachlor degradation, which was different from some previously reported heterogeneous Fenton counterparts. Moreover, the •OH generation rate constant of this surface Fenton system was 102 - 104 times those of previous heterogeneous Fenton processes. The interaction between α-FeOOH and NH2OH was investigated with using attenuated total reflectance Fourier transform infrared spectroscopy and density functional theory calculations. The effective degradation of organic pollutants in this surface Fenton system was ascribed to the efficient Fe(III)/Fe(II) cycle on the α-FeOOH surface promoted by NH2OH, which was confirmed by X-ray photoelectron spectroscopy analysis. The degradation intermediates and mineralization of alachlor in this surface Fenton system were then systematically investigated using total organic carbon and ion chromatography, liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry. This study offers a new strategy to degrade organic pollutants, and also sheds light on the environmental effects of goethite.

  6. Air pollutants degrade floral scents and increase insect foraging times

    NASA Astrophysics Data System (ADS)

    Fuentes, Jose D.; Chamecki, Marcelo; Roulston, T.'ai; Chen, Bicheng; Pratt, Kenneth R.

    2016-09-01

    Flowers emit mixtures of scents that mediate plant-insect interactions such as attracting insect pollinators. Because of their volatile nature, however, floral scents readily react with ozone, nitrate radical, and hydroxyl radical. The result of such reactions is the degradation and the chemical modification of scent plumes downwind of floral sources. Large Eddy Simulations (LES) are developed to investigate dispersion and chemical degradation and modification of floral scents due to reactions with ozone, hydroxyl radical, and nitrate radical within the atmospheric surface layer. Impacts on foraging insects are investigated by utilizing a random walk model to simulate insect search behavior. Results indicate that even moderate air pollutant levels (e.g., ozone mixing ratios greater than 60 parts per billion on a per volume basis, ppbv) substantially degrade floral volatiles and alter the chemical composition of released floral scents. As a result, insect success rates of locating plumes of floral scents were reduced and foraging times increased in polluted air masses due to considerable degradation and changes in the composition of floral scents. Results also indicate that plant-pollinator interactions could be sensitive to changes in floral scent composition, especially if insects are unable to adapt to the modified scentscape. The increase in foraging time could have severe cascading and pernicious impacts on the fitness of foraging insects by reducing the time devoted to other necessary tasks.

  7. EFFECTS OF POLLUTANTS ON BIOLOGICAL SYSTEMS. CHAPTER FROM THE ENERGY AND ENVIRONMENT DIVISION ANNUAL REPORT 1979

    SciTech Connect

    Authors, Various

    1980-10-01

    Planning a rational energy future requires anticipating the environmental consequences of various technologies. This is difficult to do with precision as the effects of pollutants are often determined by interactions between and among complex physical (abiotic) and biological (biotic) systems. A given pollutant may affect human beings through direct exposure or indirectly through inducing changes to biological systems which humans need to utilize. The concentration of a toxin in the food chain or the destruction of organisms necessary for the maintenance of high quality water are examples of indirect effects. Pollutants can be transformed and/or degraded as they establish residence in various components of an ecosystem. Anticipation and amelioration of pollutant effects involves the integration of a vast range of data. This data includes: (1) physical and chemical characterization cf the pollutant as it enters the environment; (2) determining effects on the various components (biotic and abiotic) within the context of the functioning ecosystem of interest; (3) transformation in movements and/or degradation of the pollutant within that ecosystem and within specific organisms and physical components; and (4) determining a detailed biochemical and biological picture of the interactions of pollutants with particular organisms and/or their cellular components judged salient for various processes. The major programs described below are designed to answer parts of the above fundamental questions relevant to pollutants generated by energy related technologies. Their emphasis is on anticipating consequences to the biological components of various ecosystems. The work ranges from studies involving parts of a single cell (the membranes) to studies involving the whole ecosystem (in the pelagic zone of a lake). The programs take advantage of expertise and technical abilities present at LBL. Two small exploratory projects which were of brief duration and not related to

  8. The Practice of Water Pollution Biology.

    ERIC Educational Resources Information Center

    Mackenthun, Kenneth M.

    Water pollution techniques and practices, including data analysis, interpretation and display are described in this book intended primarily for the biologist inexperienced in this work, and for sanitary engineers, chemists, and water pollution control administrators. The characteristics of aquatic environments, their biota, and the effects of…

  9. Roles of Protein Ubiquitination and Degradation Kinetics in Biological Oscillations

    PubMed Central

    Xu, Lida; Qu, Zhilin

    2012-01-01

    Protein ubiquitination and degradation play important roles in many biological functions and are associated with many human diseases. It is well known that for biochemical oscillations to occur, proper degradation rates of the participating proteins are needed. In most mathematical models of biochemical reactions, linear degradation kinetics has been used. However, the degradation kinetics in real systems may be nonlinear, and how nonlinear degradation kinetics affects biological oscillations are not well understood. In this study, we first develop a biochemical reaction model of protein ubiquitination and degradation and calculate the degradation rate against the concentration of the free substrate. We show that the protein degradation kinetics mainly follows the Michaelis-Menten formulation with a time delay caused by ubiquitination and deubiquitination. We then study analytically how the Michaelis-Menten degradation kinetics affects the instabilities that lead to oscillations using three generic oscillation models: 1) a positive feedback mediated oscillator; 2) a positive-plus-negative feedback mediated oscillator; and 3) a negative feedback mediated oscillator. In all three cases, nonlinear degradation kinetics promotes oscillations, especially for the negative feedback mediated oscillator, resulting in much larger oscillation amplitudes and slower frequencies than those observed with linear kinetics. However, the time delay due to protein ubiquitination and deubiquitination generally suppresses oscillations, reducing the amplitude and increasing the frequency of the oscillations. These theoretical analyses provide mechanistic insights into the effects of specific proteins in the ubiquitination-proteasome system on biological oscillations. PMID:22506034

  10. Biological degradation and solubilisation of coal.

    PubMed

    Sekhohola, Lerato M; Igbinigie, Eric E; Cowan, A Keith

    2013-06-01

    This review focuses on ligninolytic fungi, soil bacteria, plants and root exudates in the degradation and solubilisation of low grade and waste coal and the interaction between these mutualistic biocatalysts. Coal represents a considerable portion of the total global fossil fuel reserve and continued demand for, and supply of this resource generates vast quantities of spoil and low grade waste. Large scale bioremediation technologies for the beneficiation of waste coal have unfortunately not yet been realised despite the many discoveries of microorganisms capable of lignite, lignin, and humic acid breakdown. Even so, solubilisation and depolymerization of low grade coal appears to involve either ligninolytic enzyme action or the production of alkaline substances or both. While the precise mechanism of coal biosolubilisation is unclear, a model for the phyto-biodegradation of low rank coal by mutualistic interaction between ligninolytic microorganisms and higher plants is proposed. Based on accumulated evidence this model suggests that solubilisation and degradation of lignite and waste coals commences upon plant root exudate and ligninolytic microorganism interaction, which is mutualistic, and includes soil bacteria and both mycorrhizal and non-mycorrhizal fungi. It is envisaged that this model and its further elaboration will aid in the development of functional technologies for commercial bioremediation of coal mine spoils, contribute to soil formation, and the overall biogeochemistry of organic carbon in the global ecosystem.

  11. Linking chemical contamination to biological effects in coastal pollution monitoring.

    PubMed

    Beiras, Ricardo; Durán, Iria; Parra, Santiago; Urrutia, Miren B; Besada, Victoria; Bellas, Juan; Viñas, Lucía; Sánchez-Marín, Paula; González-Quijano, Amelia; Franco, María A; Nieto, Óscar; González, Juan J

    2012-01-01

    To establish the connection between pollutant levels and their harmful effects on living resources, coastal monitoring programmes have incorporated biological tools, such as the scope for growth (SFG) in marine mussels and benthic macrofauna community indices. Although the relation between oxygen-depleting anthropogenic inputs and the alteration of benthic communities is well described, the effects of chemical pollutants are unknown because they are not expected to favour any particular taxa. In this study, the combined efforts of five research teams involved in the investigative monitoring of marine pollution allowed the generation of a multiyear data set for Ría de Vigo (NW Iberian Peninsula). Multivariate analysis of these data allowed the identification of the chemical-matrix combinations responsible for most of the variability among sites and the construction of a chemical pollution index (CPI) that significantly (P < 0.01) correlated with biological effects at both the individual and the community levels. We report a consistent reduction in the physiological fitness of local populations of mussels as chemical pollution increases. The energy balance was more sensitive to pollution than individual physiological rates, but the reduction in the SFG was primarily due to significantly decreased clearance rates. We also found a decrease in benthic macrofauna diversity as chemical pollution increases. This diversity reduction resulted not from altered evenness, as the classic paradigm might suggest, but from a loss of species richness.

  12. Water pollution and habitat degradation in the Gulf of Thailand.

    PubMed

    Cheevaporn, Voravit; Menasveta, Piamsak

    2003-01-01

    The Gulf of Thailand has been a major marine resource for Thai people for a long time. However, recent industrialization and community development have exerted considerable stress on the marine environments and provoked habitat degradation. The following pollution problems in the Gulf have been prioritized and are discussed in details: (1) Untreated municipal and industrial waste water are considered to be the most serious problems of the country due to limited waste water treatment facilities in the area. (2) Eutrophication is an emerging problem in the gulf of Thailand. Fortunately, the major species of phytoplankton that have been reported as the cause of red tide phenomena were non-toxic species such as Noctiluca sp. and Trichodesmium sp. (3) Few problems have been documented from trace metals contamination in the Gulf of Thailand and public health threat from seafood contamination does not appear to be significant yet. (4) Petroleum hydrocarbon residue contamination is not a problem, although a few spills from small oil tankers have been recorded. A rapid decrease in mangrove forest, coral reefs, and fisheries resources due to mismanagement is also discussed.

  13. Recent progress on application of UV excilamps for degradation of organic pollutants and microbial inactivation.

    PubMed

    Matafonova, Galina; Batoev, Valeriy

    2012-10-01

    Excilamps as modern mercury-free sources of narrow-band UV radiation represent an attractive alternative in environmental applications. This review focuses on recent studies on the water and surface decontamination with excilamps by means of direct photolysis and advanced oxidation processes. To date, direct photolysis and advanced oxidation processes (AOPs) such as UV/H(2)O(2), UV/Fenton and UV/O(3) have been applied for degradation of organic compounds (mainly, phenols, dyes and herbicides) in model aqueous solutions. Special emphasis is placed on studies combining UV irradiation (as a pre-treatment or post-treatment step) with biological treatment. In this review, the efficiencies of direct UV, UV/H(2)O(2) and UV/TiO(2) processes for inactivation of a variety of pathogenic microorganisms in water and on surfaces are discussed. The analysis of the literature shows that more works need to be done on scaling up the processes, degradation/mineralization of target pollutant(s) in real effluents and evaluation of energy requirements.

  14. Biological effects of air pollution in Sao Paulo and Cubatao

    SciTech Connect

    Boehm, G.M.S.; Saldiva, P.H.; Pasqualucci, C.A.; Massad, E.; Martins M de, E.; Zin, W.A.; Cardoso, W.V.; Criado, P.M.; Komatsuzaki, M.; Sakae, R.S. )

    1989-08-01

    Rats were used as biological indicators of air quality in two heavily polluted Brazilian towns: Sao Paulo and Cubatao. They were exposed for 6 months to ambient air in areas where the pollution was known to be severe. The following parameters were studied and compared to those of control animals: respiratory mechanics, mucociliary transport, morphometry of respiratory epithelium and distal air spaces, and general morphological alterations. The results showed lesions of the distal and upper airways in rats exposed in Cubatao, whereas the animals from Sao Paulo showed only alterations of the upper airways but of greater intensity than those observed in the Cubatao group. There are both qualitative and quantitative differences in the pollutants of these places: in Sao Paulo automobile exhaust gases dominate and in Cubatao the pollution is due mainly to particulates of industrial sources. The correlation of the pathological findings with the pollutants is discussed and it is concluded that biological indicators are useful to monitor air pollutions which reached dangerous levels in Sao Paulo and Cubatao.

  15. River Pollution: Part II. Biological Methods for Assessing Water Quality.

    ERIC Educational Resources Information Center

    Openshaw, Peter

    1984-01-01

    Discusses methods used in the biological assessment of river quality and such indicators of clean and polluted waters as the Trent Biotic Index, Chandler Score System, and species diversity indexes. Includes a summary of a river classification scheme based on quality criteria related to water use. (JN)

  16. Quantitation and detection of vanadium in biologic and pollution materials

    NASA Technical Reports Server (NTRS)

    Gordon, W. A.

    1974-01-01

    A review is presented of special considerations and methodology for determining vanadium in biological and air pollution materials. In addition to descriptions of specific analysis procedures, general sections are included on quantitation of analysis procedures, sample preparation, blanks, and methods of detection of vanadium. Most of the information presented is applicable to the determination of other trace elements in addition to vanadium.

  17. Physical insights into the sonochemical degradation of recalcitrant organic pollutants with cavitation bubble dynamics.

    PubMed

    Sivasankar, Thirugnanasambandam; Moholkar, Vijayanand S

    2009-08-01

    This paper tries to discern the mechanistic features of sonochemical degradation of recalcitrant organic pollutants using five model compounds, viz. phenol (Ph), chlorobenzene (CB), nitrobenzene (NB), p-nitrophenol (PNP) and 2,4-dichlorophenol (2,4-DCP). The sonochemical degradation of the pollutant can occur in three distinct pathways: hydroxylation by ()OH radicals produced from cavitation bubbles (either in the bubble-bulk interfacial region or in the bulk liquid medium), thermal decomposition in cavitation bubble and thermal decomposition at the bubble-liquid interfacial region. With the methodology of coupling experiments under different conditions (which alter the nature of the cavitation phenomena in the bulk liquid medium) with the simulations of radial motion of cavitation bubbles, we have tried to discern the relative contribution of each of the above pathway to overall degradation of the pollutant. Moreover, we have also tried to correlate the predominant degradation mechanism to the physico-chemical properties of the pollutant. The contribution of secondary factors such as probability of radical-pollutant interaction and extent of radical scavenging (or conservation) in the medium has also been identified. Simultaneous analysis of the trends in degradation with different experimental techniques and simulation results reveals interesting mechanistic features of sonochemical degradation of the model pollutants. The physical properties that determine the predominant degradation pathway are vapor pressure, solubility and hydrophobicity. Degradation of Ph occurs mainly by hydroxylation in bulk medium; degradation of CB occurs via thermal decomposition inside the bubble, degradation of PNP occurs via pyrolytic decomposition at bubble interface, while hydroxylation at bubble interface contributes to degradation of NB and 2,4-DCP.

  18. New Photocatalysis for Effective Degradation of Organic Pollutants in Water

    NASA Astrophysics Data System (ADS)

    Zarei Chaleshtori, M.; Saupe, G. B.; Masoud, S.

    2009-12-01

    The presence of harmful compounds in water supplies and in the discharge of wastewater from chemical industries, power plants, and agricultural sources is a topic of global concern. The processes and technologies available at the present time for the treatment of polluted water are varied that include traditional water treatment processes such as biological, thermal and chemical treatment. All these water treatment processes, have limitations of their own and none is cost effective. Advanced oxidation processes have been proposed as an alternative for the treatment of this kind of wastewater. Heterogeneous photocatalysis has recently emerged as an efficient method for purifying water. TiO2 has generally been demonstrated to be the most active semiconductor material for decontamination water. One significant factor is the cost of separation TiO2, which is generally a powder having a very small particle size from the water after treatment by either sedimentation or ultrafiltration. The new photocatalyst, HTiNbO5, has been tested to determine whether its photocatalytic efficiency is good enough for use in photocatalytic water purification since it has high surface area and relatively large particle size. The larger particle sizes of the porous materials facilitate catalyst removal from a solution, after purification has taken place. It can be separated from water easily than TiO2, a significant technical improvement that might eliminate the tedious final filtration necessary with a slurry. These materials are characterized and tested as water decontamination photocatalysts. The new catalyst exhibited excellent catalytic activity, but with a strong pH dependence on the photo efficiency. These results suggest that elimination of the ion exchange character of the catalyst may greatly improve its performance at various pHs. This new research proposes to study the effects of a topotactic dehydration reaction on these new porous material catalysts.

  19. Soil degradation effect on biological activity in Mediterranean calcareous soils

    NASA Astrophysics Data System (ADS)

    Roca-Pérez, L.; Alcover-Sáez, S.; Mormeneo, S.; Boluda, R.

    2009-04-01

    Soil degradation processes include erosion, organic matter decline, compaction, salinization, landslides, contamination, sealing and biodiversity decline. In the Mediterranean region the climatological and lithological conditions, together with relief on the landscape and anthropological activity are responsible for increasing desertification process. It is therefore considered to be extreme importance to be able to measure soil degradation quantitatively. We studied soil characteristics, microbiological and biochemical parameters in different calcareous soil sequences from Valencia Community (Easter Spain), in an attempt to assess the suitability of the parameters measured to reflect the state of soil degradation and the possibility of using the parameters to assess microbiological decline and soil quality. For this purpose, forest, scrubland and agricultural soil in three soil sequences were sampled in different areas. Several sensors of the soil biochemistry and microbiology related with total organic carbon, microbial biomass carbon, soil respiration, microorganism number and enzyme activities were determined. The results show that, except microorganism number, these parameters are good indicators of a soil biological activity and soil quality. The best enzymatic activities to use like indicators were phosphatases, esterases, amino-peptidases. Thus, the enzymes test can be used as indicators of soil degradation when this degradation is related with organic matter losses. There was a statistically significant difference in cumulative O2 uptake and extracellular enzymes among the soils with different degree of degradation. We would like to thank Spanish government-MICINN for funding and support (MICINN, project CGL2006-09776).

  20. Biological degradation and composition of inedible sweetpotato biomass

    NASA Technical Reports Server (NTRS)

    Trotman, A. A.; Almazan, A. M.; Alexander, A. D.; Loretan, P. A.; Zhou, X.; Lu, J. Y.

    1996-01-01

    Many challenges are presented by biological degradation in a bioregenerative Controlled Ecological Life Support System (CELSS) as envisioned by the U.S. National Aeronautics and Space Administration (NASA). In the studies conducted with biodegradative microorganism indigenous to sweetpotato fields, it was determined that a particle size of 75 microns and incubation temperature of 30 degrees C were optimal for degradation. The composition of the inedible biomass and characterization of plant nutrient solution indicated the presence of potential energy sources to drive microbial transformations of plant waste. Selected indigenous soil isolates with ligno-cellulolytic or sulfate-reducing ability were utilized in biological studies and demonstrated diversity in ability to reduce sulfate in solution and to utilize alternative carbon sources: a lignin analog--4-hydroxy, 3-methoxy cinnamic acid, cellulose, arabinose, glucose, sucrose, mannitol, galactose, ascorbic acid.

  1. Biological degradation and composition of inedible sweetpotato biomass

    NASA Astrophysics Data System (ADS)

    Trotman, A. A.; Almazan, A. M.; Alexander, A. D.; Loretan, P. A.; Zhou, X.; Lu, J. Y.

    1996-01-01

    Many challenges are presented by biological degradation in a bioregenerative Controlled Ecological Life Support System (CELSS) as envisioned by the U.S. National Aeronautics and Space Administration (NASA). In the studies conducted with biodegradative microorganism indigenous to sweetpotato fields, it was determined that a particle size of 75 microns and incubation temperature of 30 degC were optimal for degradation. The composition of the inedible biomass and characterization of plant nutrient solution indicated the presence of potential energy sources to drive microbial transformations of plant waste. Selected indigenous soil isolates with ligno-cellulolytic or sufate-reducing ability were utilized in biological studies and demonstrated diversity in ability to reduce sulfate in solution and to utilize alternative carbon sources: a lignin analog-4-hydroxy, 3-methoxy cinnamic acid, cellulose, arabinose, glucose, sucrose, mannitol, galactose, ascorbic acid.

  2. Biological degradation and composition of sweet potato biomass - errata

    NASA Astrophysics Data System (ADS)

    Trotman, A. A.; Almazan, A. M.; Alexander, A. D.; Loretan, P. A.; Zhou, X.; Lu, J. Y.

    1996-01-01

    Many challenges are presented by biological degradation in a bioregenerative Controlled Ecological Life Support System as envisioned by the U.S. National Aeronautics and Space Administration. In studies conducted with biodegradative microorganisms indigenous to sweetpotato fields, it was determined that a particle size of 75 microns and incubation temperature of 30 degC were optimal for degradation. The composition of the biomass and characterization of plant nutrient solution indicated the presence of potential energy sources to drive microbial transformations of plant waste. Selected indigenous soil isolates with ligno-cellulolytic or sulfate-reducing ability were utilized in biological studies and demonstrated diversity in their ability to reduce sulfate in solution and to utilize alternative carbon sources: a lignin analog 4-hydroxy, 3-methoxy cinnamic acid, cellulose, arabinose, glucose, sucrose, mannitol, galactose, ascorbic acid.

  3. Degradation of Polycyclic Aromatic Hydrocarbons (PAHs) by Bacteria Isolated from Light Oil Polluted Soils

    NASA Astrophysics Data System (ADS)

    Ohnuma, T.; Suto, K.; Inoue, C.

    2007-03-01

    Polycyclic aromatic hydrocarbons (PAHs) have polluted soil and groundwater widely and for long term because of their low solubility at normal temperature. Several microorganisms, such as Pseudomonas sp., Sphigomonas sp., a white-rot fungus and so on, being able to decompose PAHs, have been isolated and researched. This study reported to investigate biodegradation of low molecule PAH by isolated bacteria from light oil polluted soil. 12 isolates were obtained from a light oil polluted soil using naphthalene, fluorene and anthracene as sole carbon source, of which 4 isolates grew with naphthalene, 4 isolates did with fluorene and 4 isolates did with anthracene. Among them 3 isolates showed the ability to degrade phenanthrene additionally. These phenanthrene degradation and growth rates were almost same as that of S. yanoikuyae (DSM6900), which is the typical bacteria of PAHs degrader. Therefore, the isolate seemed to have an expectation for PAHs degradation.

  4. Photocatalytic degradation of pollutants from Elcogas IGCC power station effluents.

    PubMed

    Durán, A; Monteagudo, J M; San Martín, I; García-Peña, F; Coca, P

    2007-06-01

    The aim of this work is to improve the quality of water effluents coming from Elcogas IGCC power station (Puertollano, Spain) with the purpose of fulfilling future more demanding normative, using heterogeneous photocatalytic oxidation processes (UV/H(2)O(2)/TiO(2) or ZnO). The efficiency of photocatalytic degradation for the different catalysts (TiO(2) and ZnO) was determined from the analysis of the following parameters: cyanides, formates and ammonia content. In a first stage, the influence of two parameters (initial concentration of H(2)O(2) and amount of catalyst) on the degradation kinetics of cyanides and formates was studied based on a factorial experimental design. pH was always kept in a value >9.5 to avoid gaseous HCN formation. The degradation of cyanides and formates was found to follow pseudo-first order kinetics. Experimental kinetic constants were fitted using neural networks (NNs). The mathematical model reproduces experimental data within 90% of confidence and allows the simulation of the process for any value of parameters in the experimental range studied. Moreover, a measure of the saliency of the input variables was made based upon the connection weights of the neural networks, allowing the analysis of the relative relevance of each variable with respect to the others. Results showed that the photocatalytic process was effective, being the degradation rate of cyanides about five times higher when compared to removal of formates. Finally, the effect of lowering pH on the degradation of formates was evaluated after complete cyanides destruction was reached (10 min of reaction). Under the optimum conditions (pH 5.2, [H(2)O(2)]=40 g/l; [TiO(2)]=2g/l), 100% of cyanides and 92% of initial NH(3) concentration are degraded after 10 min, whereas 35 min are needed to degrade 98% of formates.

  5. Selective photocatalytic degradation of aquatic pollutants by titania encapsulated into FAU-type zeolites.

    PubMed

    Zhang, Guan; Choi, Wonyong; Kim, Seok Han; Hong, Suk Bong

    2011-04-15

    The selective photocatalytic degradation of charged pollutants in water was achieved on titania encapsulated into FAU-type zeolites. The electrostatic attraction of cationic substrates and repulsion of anionic substrates by the negatively charged zeolite framework facilitated the selective photocatalytic degradation of charged substrates. The hybrid zeolite-titania photocatalysts were prepared through the ion-exchange method. The titania clusters were mainly well distributed within the cavities of FAU-type zeolites whereas no TiO(2) nanoparticles aggregates were observed on the external surface of zeolite crystals. The hybrid zeolite-titania photocatalysts were characterized by diffuse reflectance UV-visible spectroscopy, transmission electron microscopy, energy-dispersive X-ray analysis and X-ray photoelectron spectroscopy. The selective degradation of charged pollutants was investigated by employing three pairs of oppositely charged substrates. The comparison between the cationic and anionic substrates clearly showed that the degradation rates for the cationic substrates on the hybrid photocatalysts are markedly higher than those for the anionic substrates. Among the cationic substrates, the smaller cations such as tetramethylammoniums were preferentially degraded. This enabled the selective removal of cationic substrates among the mixture. Such a selective photocatalytic degradation of water pollutants may provide a useful strategy for the development of economical photocatalytic process by targeting only the most recalcitrant pollutant.

  6. Partial degradation of five pesticides and an industrial pollutant by ozonation in a pilot-plant scale reactor.

    PubMed

    Maldonado, M I; Malato, S; Pérez-Estrada, L A; Gernjak, W; Oller, I; Doménech, Xavier; Peral, José

    2006-11-16

    Aqueous solutions of a mixture of several pesticides (alachlor, atrazine, chlorfenvinphos, diuron and isoproturon), considered PS (priority substances) by the European Commission, and an intermediate product of the pharmaceutical industry (alpha-methylphenylglycine, MPG) chosen as a model industrial pollutant, have been degraded at pilot-plant scale using ozonation. This study is part of a large research project [CADOX Project, A Coupled Advanced Oxidation-Biological Process for Recycling of Industrial Wastewater Containing Persistent Organic Contaminants, Contract No.: EVK1-CT-2002-00122, European Commission, http://www.psa.es/webeng/projects/cadox/index.html] founded by the European Union that inquires into the potential coupling between chemical and biological oxidations for the removal of toxic or non-biodegradable contaminants from water. The evolution of pollutant concentration, TOC mineralization, generation of inorganic species and consumption of O3 have been followed in order to visualize the chemical treatment effectiveness. Although complete mineralization is hard to accomplish, and large amounts of the oxidant are required to lower the organic content of the solutions, the possibility of ozonation cannot be ruled out if partial degradation is the final goal wanted. In this sense, Zahn-Wellens biodegradability tests of the ozonated MPG solutions have been performed, and the possibility of a further coupling with a secondary biological treatment for complete organic removal is envisaged.

  7. Use of biolog methodology for optimizing the degradation of hydrocarbons by bacterial consortia.

    PubMed

    Ambrosoli, R; Bardi, L; Minati, J L; Belviso, S; Ricci, R; Marzona, M

    2003-01-01

    Biolog methodology was used for the preliminary screening of different cultural conditions in order to detect the best combination/s of factors influencing the metabolic performance of bacterial consortia active in the degradation of hydrocarbons. Two microbial consortia were tested for their activity on 2 hydrocarbons (nonadecane and eicosane) in presence of the following cultural coadjuvants: vegetal oil, beta-cyclodextrine, sodium acetate, mineral solution. Tests were conducted in Biolog MT plates, where only the redox indicator of microbial growth (tetrazolium violet) and no carbon sources are provided. The microwells were filled with various combinations of hydrocarbons, microbial inoculum and coadjuvants. Blanks were prepared with the same combinations but without hydrocarbons. The results obtained show the suitability of the methodology developed to identify the most active consortium and the conditions for its best degradation performance. The efficacy of Biolog methodology (Biolog Inc., USA) for the characterization of microbial communities on the basis of the metabolic profiles obtained on specific carbon sources in the microwells of Elisa-type plates, is widely acknowledged (Garland, 1997; Pietikäinen et al., 2000; Dauber and Wolters, 2000). Due to its aptitude to simultaneously evaluate multiple microbial responses and directly organize the results, it can be adapted to meet specific study purposes (Gamo and Shji, 1999). In the present research Biolog methodology was fitted for the preliminary screening of different cultural conditions, in order to detect the best combination/s of factors influencing the metabolic performance of bacterial consortia active in the degradation of aliphatic hydrocarbons, in view of their utilization for the bioremediation of polluted sites.

  8. Degradation of diesel-originated pollutants in wetlands by Scirpus triqueter and microorganisms.

    PubMed

    Liu, Xiaoyan; Wang, Zhenzhen; Zhang, Xinying; Wang, Jun; Xu, Gang; Cao, Zhengnan; Zhong, Chenglin; Su, Pengcheng

    2011-10-01

    The wetland ecological environment near Huangpu-Yangtze River Estuary (HYRE) is deteriorating more and more seriously due to oil spills. In this paper, the simulation experiment of degradation was conducted to restore the diesel pollution in soils where the decontaminating potential of indigenous hydrocarbon-degrading microorganisms (HDMs) was evaluated with pot experiments and the co-activation between HDMs and native plant, Scirpus triqueter L.(STL), was investigated. The experimental results indicated that HDMs isolated from HYRE wetland had a degradation effect on diesel pollutants. Within 60 days, the removal ratio of diesel compared with initial amount could be up to 57.27 ± 8.18% in the HDMs inoculated soils at different concentrations of diesel. It was also found that the growth of Scirpus triqueter could enhance the degradation and remediation of diesel pollutants by increasing the populations of microorganisms. A community of STL and HDMs showed a remarkable capability of degrading hydrocarbon components in diesels. Under the combined effects of HDMs and STL (STL-Ms), the removal ratio of diesel pollutants could reach 67.42 ± 8.92%. For example, at 15,000 mg kg(-1) diesel concentration the removal ratios in the HDMs and STL-Ms soils were 67.41% and 72.62%, respectively. Moreover, the saturated hydrocarbons were more readily degraded than the aromatic hydrocarbons in treated soils showing a good degradation effect on the range of C(16)-C(24)n-alkanes, especially C(19). Positive correlations between microbial populations and diesel removal ratios were observed during the experiment. Microbial populations were found significantly higher in the HDMs soils and rhizosphere soils than in the control ones. The results confirmed that the HDMs and plant improved the biodegradation ability for diesel pollutants and they could be reasonably matched to cure and restore the ecological environment of oil-contaminated wetlands.

  9. Sensitized photolysis as pretreatment to biological degradation of trichlorobenzenes

    SciTech Connect

    Kim, Jae Hyoun.

    1991-01-01

    The role of photolysis as pretreatment process was examined for the biological degradation of trichlorobenzenes (TCBs), namely 1,2,3-, 1,2,4- and 1,3,5-trichlorobenzenes. Initially, direct and indirect photolysis experiments were conducted using aqueous solutions with 1% acetonitrile of the three isomers of trichlorobenzenes with and without sensitizers. The sensitizers used were Fenton's reagent, nitrite, triethylamine, humic acid and TiO{sub 2}. The photochemical experiments were performed using laboratory simulated sunlight and the kinetic rates for these processes were calculated. The effect of photolysis on the biological degradation chlorobenzenes were examined using a chemical activation system (CAS) which consists of EDTA, ferrous sulfate, ascorbic acid, catalase and H{sub 2}O{sub 2} in potassium phosphate buffer (monobasic) and a primary sewage effluent. Initially, kinetic rates by CAS biodegradation and primary sewage were obtained and compared. In general, the rates of biodegradation were greater in the test media with catalase. The rate of transformation in CAS was enhanced in the order: monoCB < 1,2,3-TCB < 1,2,4-TCB < 1,3,5-TCB; whereas, when CAS was used as a control, the kinetic rates in the presence of catalase increased in the sequence: 1,2,3-TCB, 1,3,5-TCB < 1,2,4-TCB < MonoCB. Photolysis studied in concert with the biological systems showed significant enhancement of the degradation rate of trichlorobenzenes. The photolysis rates were higher for those with sensitized photolysis. This study shows that photolysis can be used as a pretreatment of enhancing biodegradation of trichlorobenzenes in aqueous systems.

  10. Degradation of environment pollutant dyes using phytosynthesized metal nanocatalysts

    NASA Astrophysics Data System (ADS)

    MeenaKumari, M.; Philip, Daizy

    2015-01-01

    We present for the first time biogenic reduction and stabilization of gold and silver ions at room temperature using fruit juice of Punica granatum. The formation, morphology and crystalline structure of the synthesized nanoparticles are determined using UV-Visible, XRD and TEM. An attempt to reveal the partial role of phenolic hydroxyls in the reduction of Au3+ and Ag+ is done through FTIR analysis. The synthesized nanoparticles are used as potential catalysts in the degradation of a cationic phenothiazine dye, an anionic mono azo dye and a cationic fluorescent dye. The calculated values of percentage removal of dyes and the rate constants from pseudo first order kinetic data fit give a comparative study on degradation of organic dyes in presence of prepared gold and silver nanoparticles.

  11. Microbial Hydrocarbon and ToxicPollutant Degradation Method

    SciTech Connect

    Schlueter, Dietrich; Janabi, Mustafa; O'Neil, James; Budinger, Thomas

    2011-08-16

    The goal of this project is to determine optimum conditions for bacterial oxidation of hydrocarbons and long-chain alkanes that are representative of petroleum contamination of the environment. Polycyclic Aromatic Hydrocarbons (PAHs) are of concern because of their toxicity, low volatility, and resistance to microbial degradation, especially under anaerobic conditions. The uniqueness of our approach is to use carbon-11 in lieu of the traditional use of carbon-14.

  12. Efficient degradation of organic pollutants in aqueous solution with bicarbonate-activated hydrogen peroxide.

    PubMed

    Xu, Aihua; Li, Xiaoxia; Xiong, Hui; Yin, Guochuan

    2011-02-01

    Bicarbonate anion is an efficient activator for hydrogen peroxide to generate many active oxygen species including peroxymonocarbonate (HCO(4)(-)), superoxide ion (O(2)(-)) and singlet oxygen ((1)O(2)). This study aims to understand the oxidative degradation of organic pollutants including methyl blue, methyl orange, rhodamine B, and 4-chlorophenol, with H(2)O(2) activated by sodium bicarbonate at room temperature. The obtained results indicate that such a method is apparently efficient in versatile pollutant degradation. Compared with using H(2)O(2) alone under similar pH conditions, the degradation rates of the pollutants were greatly enhanced through adding NaHCO(3). Through LC-MS, FT-IR and the TOC analysis, the degradation of methylene blue was revealed to proceed by the transformation of dimethylamino group in methylene blue to methylamino, aldehyde and nitro group, and the opening of phenyl ring into small molecular compounds and CO(2). The studies using the (1)O(2) scavenger sodium azide and the O(2)(-) indicator nitro blue tetrazolium suggest that the active O(2)(-) intermediate, generated from HCO(4)(-) decomposition, rather than (1)O(2) was involved in the pollutant degradation.

  13. Evidence of laser induced degradation and graphitization of aromatic pollutants

    NASA Astrophysics Data System (ADS)

    Mele, A.; Letardi, T.; di Lazarro, P.

    The laser-induced photodecomposition and graphitization of polynuclear aromatic hydrocarbons is investigated by irradiating solid pollutant samples with an Nd-YAG laser, leaving a carbon-rich, black powder. The irradiation of anthracene and benzopyrene forms the ions Cn(+)-, CnH(+)-, and CnH2(+)- in a wide plume produced by a pulsed-CO2 laser. The tendency of aromatic compounds to fragment is noted, and the notion that ion formation is governed by the mechanism that produces ablation in the laser cloud is suggested. Optical multichannel analyzer emission spectra indicate the production of the Cn species, suggesting applications to the treatment of aromatic product wastes.

  14. Catalytical degradation of relevant pollutants from waters using magnetic nanocatalysts

    NASA Astrophysics Data System (ADS)

    Nadejde, C.; Neamtu, M.; Schneider, R. J.; Hodoroaba, V.-D.; Ababei, G.; Panne, U.

    2015-10-01

    The catalytic efficiency of two magnetically responsive nanocatalysts was evaluated for the degradation of Reactive Black 5 (RB5) and Reactive Yellow 84 (RY84) azo dyes using hydrogen peroxide as oxidant under very mild conditions (atmospheric pressure, room temperature). In order to obtain the nanocatalysts, the surface of magnetite (Fe3O4) nanoparticles, prepared by a co-precipitation method, was further modified with ferrous oxalate, a highly sensitive non-hazardous reducing agent. The sensitized nanomaterials were characterized by X-ray diffraction, scanning and transmission electron microscopy, energy-dispersive X-ray spectroscopy and vibrating sample magnetometry, and used in the catalytic wet hydrogen peroxide oxidation (CWHPO) of RB5 and RY84, in laboratory-scale experiments. The effect of important variables such as catalyst dosage, H2O2 concentration, and contact time was studied in the dye degradation kinetics. The results showed that it was possible to remove up to 99.7% dye in the presence of 20 mM H2O2 after 240 min of oxidation for a catalyst concentration of 10 g L-1 at 25 °C and initial pH value of 9.0. CWHPO of reactive dyes using sensitized magnetic nanocatalysts can be a suitable pre-treatment method for complete decolorization of effluents from textile dyeing and finishing processes, once the optimum operating conditions are established.

  15. Effective degradation of organic water pollutants by atmospheric non-thermal plasma torch and analysis of degradation process.

    PubMed

    Bansode, Avinash S; More, Supriya E; Siddiqui, Ejaz Ahmad; Satpute, Shruti; Ahmad, Absar; Bhoraskar, Sudha V; Mathe, Vikas L

    2017-01-01

    The paper reports the use of atmospheric non-thermal plasma torch as a catalyst for degradation of various organic pollutants dissolved in water. A flow of He mixed with air was used to produce the dielectric barrier discharge (DBD), at the tip of the torch, using pulsed electric excitation at 12 kV. The torch, operated at a power of 750 mW/mm(2), was seen to completely degrade the aqueous solutions of the pollutants namely methylene blue (MB), methyl orange (MO) and rhodamine-B (RB), at around 10(-4) M concentrations, the concentration of polluants is one order higher than of routinely used heterogeneous photocatalytic reactions, within 10 min of irradiation time at room temperature. UV Visible spectra of the organic dye molecules, monitored after different intervals of plasma-irradiation, ranging between 1 and 10 min, have been used as tools to quantify their sequential degradation. Further, instead of using He, only air was used to form plasma plume and used for degradation of organic dye which follow similar trend as that of He plasma. Further, Liquid Chromatography Mass Spectroscopy (LCMS) technique has been used to understand degradation pathway of methylene blue (MB) as a representative case. Total organic carbon (TOC) measurements indicates significant decrease in its content as a function of duration of plasma exposure onto methylene blue as a representative case. Toxicity studies were carried out onto Gram negative Escherichia coli. This indicated that methylene blue, without plasma treatment, shows growth inhibition, whereas with plasma treatment no inhibition was observed.

  16. Natural polymers supported copper nanoparticles for pollutants degradation

    NASA Astrophysics Data System (ADS)

    Haider, Sajjad; Kamal, Tahseen; Khan, Sher Bahadar; Omer, Muhammad; Haider, Adnan; Khan, Farman Ullah; Asiri, Abdullah M.

    2016-11-01

    In this report, chitosan (CS) was adhered on cellulose microfiber mat (CMM) to prepare CS-CMM. This was used as host for copper (Cu) nanoparticles preparation. After adsorption of Cu2+ ions from an aqueous solution of CuSO4, the metal ions entrapped in CS coating layer was treated with sodium borohydride (NaBH4) to prepare Cu nanoparticles loaded CS-CMM (Cu/CS-CMM). Fourier transform infrared spectroscopy, and X-ray diffraction confirmed the formation of Cu/CS-CMM hybrid. Scanning electron microscopy analysis was performed to reveal the morphology of the prepared catalyst. The prepared Cu/CS-CMM was employed as a catalyst for the degradation of nitro-aromatic compounds of 2-nitrophenol (2NP) and 4-nitrophenol (4NP) as well as an organic cresyl blue (CB) dye. Remarkably, the turnover frequency in the case of 2NP and 4NP using Cu/CS-CMM reaches 103.3 and 88.6 h-1, outperforming previously reported Cu nanoparticles immobilized in hydrogel-based catalytic systems. The rate constants for 2NP, 4NP and CB were 1.2 × 10-3 s-1, 2.1 × 10-3 s-1 and, 1.3 × 10-3 s-1, respectively. Besides, we discussed the separation of the catalyst from the reaction mixture and its re-usability.

  17. Induction, regulation, degradation, and biological significance of mammalian metallothioneins.

    PubMed

    Miles, A T; Hawksworth, G M; Beattie, J H; Rodilla, V

    2000-01-01

    MTs are small cysteine-rich metal-binding proteins found in many species and, although there are differences between them, it is of note that they have a great deal of sequence and structural homology. Mammalian MTs are 61 or 62 amino acid polypeptides containing 20 conserved cysteine residues that underpin the binding of metals. The existence of MT across species is indicative of its biological demand, while the conservation of cysteines indicates that these are undoubtedly central to the function of this protein. Four MT isoforms have been found so far, MT-1, MT-2, MT-3, and MT-4, but these also have subtypes with 17 MT genes identified in man, of which 10 are known to be functional. Different cells express different MT isoforms with varying levels of expression perhaps as a result of the different function of each isoform. Even different metals induce and bind to MTs to different extents. Over 40 years of research into MT have yielded much information on this protein, but have failed to assign to it a definitive biological role. The fact that multiple MT isoforms exist, and the great variety of substances and agents that act as inducers, further complicates the search for the biological role of MTs. This article reviews the current knowledge on the biochemistry, induction, regulation, and degradation of this protein in mammals, with a particular emphasis on human MTs. It also considers the possible biological roles of this protein, which include participation in cell proliferation and apoptosis, homeostasis of essential metals, cellular free radical scavenging, and metal detoxification.

  18. Microwaves and their coupling to advanced oxidation processes: enhanced performance in pollutants degradation.

    PubMed

    Nascimento, Ulisses M; Azevedo, Eduardo B

    2013-01-01

    This review assesses microwaves (MW) coupled to advanced oxidation processes (AOPs) for pollutants degradation, as well as the basic theory and mechanisms of MW dielectric heating. We addressed the following couplings: MW/H2O2, MW/UV/H2O2, MW/Fenton, MW/US, and MW/UV/TiO2, as well as few studies that tested alternative oxidants and catalysts. Microwave Discharge Electrodeless Lamps (MDELs) are being extensively used with great advantages over ballasts. In their degradation studies, researchers generally employed domestic ovens with minor adaptations. Non-thermal effects and synergies between UV and MW radiation play an important role in the processes. Published papers so far report degradation enhancements between 30 and 1,300%. Unfortunately, how microwaves enhance pollutants is still obscure and real wastewaters scarcely studied. Based on the results surveyed in the literature, MW/AOPs are promising alternatives for treating/remediating environmental pollutants, whenever one considers high degradation yields, short reaction times, and small costs.

  19. Degradation of organic pollutants in a photoelectrocatalytic system enhanced by a microbial fuel cell.

    PubMed

    Yuan, Shi-Jie; Sheng, Guo-Ping; Li, Wen-Wei; Lin, Zhi-Qi; Zeng, Raymond J; Tong, Zhong-Hua; Yu, Han-Qing

    2010-07-15

    Photocatalytic oxidation mediated by TiO(2) is a promising oxidation process for degradation of organic pollutants, but suffers from the decreased photocatalytic efficiency attributed to the recombination of photogenerated electrons and holes. Thus, a cost-effective supply of external electrons is an effective way to elevate the photocatalytic efficiency. Here we report a novel bioelectrochemical system to effectively reduce p-nitrophenol as a model organic pollutant with utilization of the energy derived from a microbial fuel cell. In such a system, there is a synergetic effect between the electrochemical and photocatalytic oxidation processes. Kinetic analysis shows that the system exhibits a more rapid p-nitrophenol degradation at a rate two times the sum of rates by the individual photocatalytic and electrochemical methods. The system performance is influenced by both external resistor and electrolyte concentration. Either a lower external resistor or a lower electrolyte concentration results in a higher p-nitrophenol degradation rate. This system has a potential for the effective degradation of refractory organic pollutants and provides a new way for utilization of the energy generated from conversion of organic wastes by microbial fuel cells.

  20. Microwave-induced carbon nanotubes catalytic degradation of organic pollutants in aqueous solution.

    PubMed

    Chen, Jing; Xue, Shuang; Song, Youtao; Shen, Manli; Zhang, Zhaohong; Yuan, Tianxin; Tian, Fangyuan; Dionysiou, Dionysios D

    2016-06-05

    In this study, a new catalytic degradation technology using microwave induced carbon nanotubes (MW/CNTs) was proposed and applied in the treatment of organic pollutants in aqueous solution. The catalytic activity of three CNTs of 10-20nm, 20-40nm, and 40-60nm diameters were compared. The results showed that organic pollutants such as methyl orange (MO), methyl parathion (MP), sodium dodecyl benzene sulfonate (SDBS), bisphenol A (BPA), and methylene blue (MB) in aqueous solution could be degraded effectively and rapidly in MW/CNTs system. CNTs with diameter of 10-20nm exhibited the highest catalytic activity of the three CNTs under MW irradiation. Further, complete degradation was obtained using 10-20nm CNTs within 7.0min irradiation when 25mL MO solution (25mg/L), 1.2g/L catalyst dose, 450W, 2450MHz, and pH=6.0 were applied. The rate constants (k) for the degradation of SDBS, MB, MP, MO and BPA using 10-20nm CNTs/MW system were 0.726, 0.679, 0.463, 0.334 and 0.168min(-1), respectively. Therefore, this technology may have potential application for the treatment of targeted organic pollutants in wastewaters.

  1. Biological Degradation of 2,4,6-Trinitrotoluene

    PubMed Central

    Esteve-Núñez, Abraham; Caballero, Antonio; Ramos, Juan L.

    2001-01-01

    Nitroaromatic compounds are xenobiotics that have found multiple applications in the synthesis of foams, pharmaceuticals, pesticides, and explosives. These compounds are toxic and recalcitrant and are degraded relatively slowly in the environment by microorganisms. 2,4,6-Trinitrotoluene (TNT) is the most widely used nitroaromatic compound. Certain strains of Pseudomonas and fungi can use TNT as a nitrogen source through the removal of nitrogen as nitrite from TNT under aerobic conditions and the further reduction of the released nitrite to ammonium, which is incorporated into carbon skeletons. Phanerochaete chrysosporium and other fungi mineralize TNT under ligninolytic conditions by converting it into reduced TNT intermediates, which are excreted to the external milieu, where they are substrates for ligninolytic enzymes. Most if not all aerobic microorganisms reduce TNT to the corresponding amino derivatives via the formation of nitroso and hydroxylamine intermediates. Condensation of the latter compounds yields highly recalcitrant azoxytetranitrotoluenes. Anaerobic microorganisms can also degrade TNT through different pathways. One pathway, found in Desulfovibrio and Clostridium, involves reduction of TNT to triaminotoluene; subsequent steps are still not known. Some Clostridium species may reduce TNT to hydroxylaminodinitrotoluenes, which are then further metabolized. Another pathway has been described in Pseudomonas sp. strain JLR11 and involves nitrite release and further reduction to ammonium, with almost 85% of the N-TNT incorporated as organic N in the cells. It was recently reported that in this strain TNT can serve as a final electron acceptor in respiratory chains and that the reduction of TNT is coupled to ATP synthesis. In this review we also discuss a number of biotechnological applications of bacteria and fungi, including slurry reactors, composting, and land farming, to remove TNT from polluted soils. These treatments have been designed to achieve

  2. Assessing the effectiveness of regulatory controls on farm pollution using chemical and biological indices of water quality and pollution statistics.

    PubMed

    Foy, R H; Lennox, S D; Smith, R V

    2001-08-01

    Water quality was measured in 42 streams in the Colebrooke and Upper Bann catchments in Northern Ireland over the period 1990-1998. Despite ongoing pollution control measures, biological water quality, as determined by the invertebrate average score per taxon (ASPT) index, did not improve and there was no appreciable decline in recorded farm pollution incidents. However, the lack of decline in pollution incidents could reflect changes in detection policy, as a greater proportion of incidents were recorded from less polluting discharges such as farm-yard runoff. In contrast, there was an improvement during 1997 and 1998 in annual chemical water quality classification based on exceedence values (90th percentiles) for dissolved oxygen, ammonium and BOD concentrations. In 1998, 11.9% of streams were severely polluted compared to 26.2% in 1990, while the proportion classed as of salmonid water quality, increased from 40.5% in 1990 to 59.6% in 1998. Although water quality in 1996 did not improve relative to 1990 values, there was a notable increasing trend from 1990 in the numbers of samples taken during the summer which had good water quality with low ammonium (<0.6mgN l(-1)) and high dissolved oxygen (> 70% sat). The trend for samples with low BOD (<4 mgl(-1)) was more erratic, but an improvement was apparent from 1994. These improvements in chemical water quality suggest that point-source farm pollution declined after 1990. The fact that this was not reflected in stream biology may reflect the limited time scale for biological recovery. An important factor preventing biological recovery may be the high pollution capacity of manures and silage effluent, so that even reduced numbers of farm pollution incidents can severely perturb stream ecosystems. The intractable nature of farm pollution suggests that there is a need to consider an interactive approach to problem resolution involving both farmers and regulators.

  3. COP-compost: a software to study the degradation of organic pollutants in composts.

    PubMed

    Zhang, Y; Lashermes, G; Houot, S; Zhu, Y-G; Barriuso, E; Garnier, P

    2014-02-01

    Composting has been demonstrated to be effective in degrading organic pollutants (OP) whose behaviour depends on the composting conditions, the microbial populations activated and interactions with organic matters. The fate of OP during composting involves complex mechanisms and models can be helpful tools for educational and scientific purposes, as well as for industrialists who want to optimise the composting process for OP elimination. A COP-Compost model, which couples an organic carbon (OC) module and an organic pollutant (OP) module and which simulates the changes of organic matter, organic pollutants and the microbial activities during the composting process, has been proposed and calibrated for a first set of OP in a previous study. The objectives of the present work were (1) to introduce the COP-Compost model from its convenient interface to a potential panel of users, (2) to show the variety of OP that could be simulated, including the possibility of choosing between degradation through co-metabolism or specific metabolism and (3) to show the effect of the initial characteristics of organic matter quality and its microbial biomass on the simulated results of the OP dynamic. In the model, we assumed that the pollutants can be adsorbed on organic matter according to the biochemical quality of the OC and that the microorganisms can degrade the pollutants at the same time as they degrade OC (by co-metabolism). A composting experiment describing two different (14)C-labelled organic pollutants, simazine and pyrene, were chosen from the literature because the four OP fractions simulated in the model were measured during the study (the mineralised, soluble, sorbed and non-extractable fractions). Except for the mineralised fraction of simazine, a good agreement was achieved between the simulated and experimental results describing the evolution of the different organic fractions. For simazine, a specific biomass had to be added. To assess the relative importance

  4. Sequential UV-biological degradation of polycyclic aromatic hydrocarbons in two-phases partitioning bioreactors.

    PubMed

    Guieysse, Benoit; Viklund, Gunilla

    2005-04-01

    A method based on UV-irradiation in organic solvent followed by transfer of the remaining pollutants into silicone oil for subsequent biodegradation in a biphasic system inoculated with a phenanthrene degrading Pseudomonas sp. was tested for the treatment of various mixtures of PAHs. Acetone was first selected as the most suitable solvent compared to methanol, acetonitrile and silicone oil for the removal of pyrene and phenanthrene. The sequential treatment was then applied to the treatment of a mixture of fluorene, phenanthrene, anthracene, fluoranthrene, pyrene, benzo(a)anthracene and benzo(a)pyrene in acetone. These compounds were photodegraded in the following order of initial removal rates (mg l(-1) d(-1)): benzo(a)pyrene (7.8) > anthracene (5.0) > benzo(a)anthracene (2.5) > fluoranthrene (1.8) > pyrene (1.5) > phenanthrene (1.2) > fluorene (0.2). UV-treatment allowed complete removal of, anthracene, benzo(a)anthracene and benzo(a)pyrene and removals of 63% of pyrene and 37% of fluorene after 434 h or irradiation. The subsequent biological treatment removed the remaining phenanthrene and fluorene by 100% and 90%, respectively, after 790 h of cultivation. Although less efficient due to the presence of interfering compounds, the UV-biological treatment of a soil extract allowed a 63% removal of the seven PAHs named above. Microbial growth did not occur when the pollutants were directly supplied to the microorganism showing that biphasic systems reduced the toxicity effects cause by mixtures of PAHs at high concentrations. This study demonstrates the potential of selective UV treatment of high molecular weight PAHs followed by biological treatment of the low molecular weight species in biphasic systems.

  5. Selenium: environmental significance, pollution, and biological treatment technologies.

    PubMed

    Tan, Lea Chua; Nancharaiah, Yarlagadda V; van Hullebusch, Eric D; Lens, Piet N L

    2016-01-01

    Selenium is an essential trace element needed for all living organisms. Despite its essentiality, selenium is a potential toxic element to natural ecosystems due to its bioaccumulation potential. Though selenium is found naturally in the earth's crust, especially in carbonate rocks and volcanic and sedimentary soils, about 40% of the selenium emissions to atmospheric and aquatic environments are caused by various industrial activities such as mining-related operations. In recent years, advances in water quality and pollution monitoring have shown that selenium is a contaminant of potential environmental concern. This has practical implications on industry to achieve the stringent selenium regulatory discharge limit of 5μgSeL(-1) for selenium containing wastewaters set by the United States Environmental Protection Agency. Over the last few decades, various technologies have been developed for the treatment of selenium-containing wastewaters. Biological selenium reduction has emerged as the leading technology for removing selenium from wastewaters since it offers a cheaper alternative compared to physico-chemical treatments and is suitable for treating dilute and variable selenium-laden wastewaters. Moreover, biological treatment has the advantage of forming elemental selenium nanospheres which exhibit unique optical and spectral properties for various industrial applications, i.e. medical, electrical, and manufacturing processes. However, despite the advances in biotechnology employing selenium reduction, there are still several challenges, particularly in achieving stringent discharge limits, the long-term stability of biogenic selenium and predicting the fate of bioreduced selenium in the environment. This review highlights the significance of selenium in the environment, health, and industry and biotechnological advances made in the treatment of selenium contaminated wastewaters. The challenges and future perspectives are overviewed considering recent

  6. Biological function of a polysaccharide degrading enzyme in the periplasm.

    PubMed

    Wang, Yajie; Moradali, M Fata; Goudarztalejerdi, Ali; Sims, Ian M; Rehm, Bernd H A

    2016-11-08

    Carbohydrate polymers are industrially and medically important. For instance, a polysaccharide, alginate (from seaweed), is widely used in food, textile and pharmaceutical industries. Certain bacteria also produce alginate through membrane spanning multi-protein complexes. Using Pseudomonas aeruginosa as a model organism, we investigated the biological function of an alginate degrading enzyme, AlgL, in alginate production and biofilm formation. We showed that AlgL negatively impacts alginate production through its enzymatic activity. We also demonstrated that deletion of AlgL does not interfere with polymer length control, epimerization degree or stability of the biosynthesis complex, arguing that AlgL is a free periplasmic protein dispensable for alginate production. This was further supported by our protein-stability and interaction experiments. Interestingly, over-production of AlgL interfered with polymer length control, suggesting that AlgL could be loosely associated with the biosynthesis complex. In addition, chromosomal expression of algL enhanced alginate O-acetylation; both attachment and dispersal stages of the bacterial biofilm lifecycle were sensitive to the level of O-acetylation. Since this modification also protects the pathogen against host defences and enhances other virulence factors, chromosomal expression of algL could be important for the pathogenicity of this organism. Overall, this work improves our understanding of bacterial alginate production and provides new knowledge for alginate production and disease control.

  7. Biological function of a polysaccharide degrading enzyme in the periplasm

    PubMed Central

    Wang, Yajie; Moradali, M. Fata; Goudarztalejerdi, Ali; Sims, Ian M.; Rehm, Bernd H. A.

    2016-01-01

    Carbohydrate polymers are industrially and medically important. For instance, a polysaccharide, alginate (from seaweed), is widely used in food, textile and pharmaceutical industries. Certain bacteria also produce alginate through membrane spanning multi-protein complexes. Using Pseudomonas aeruginosa as a model organism, we investigated the biological function of an alginate degrading enzyme, AlgL, in alginate production and biofilm formation. We showed that AlgL negatively impacts alginate production through its enzymatic activity. We also demonstrated that deletion of AlgL does not interfere with polymer length control, epimerization degree or stability of the biosynthesis complex, arguing that AlgL is a free periplasmic protein dispensable for alginate production. This was further supported by our protein-stability and interaction experiments. Interestingly, over-production of AlgL interfered with polymer length control, suggesting that AlgL could be loosely associated with the biosynthesis complex. In addition, chromosomal expression of algL enhanced alginate O-acetylation; both attachment and dispersal stages of the bacterial biofilm lifecycle were sensitive to the level of O-acetylation. Since this modification also protects the pathogen against host defences and enhances other virulence factors, chromosomal expression of algL could be important for the pathogenicity of this organism. Overall, this work improves our understanding of bacterial alginate production and provides new knowledge for alginate production and disease control. PMID:27824067

  8. Isothermal titration calorimetry - a new method for the quantification of microbial degradation of trace pollutants.

    PubMed

    Mariana, F; Buchholz, F; Harms, H; Yong, Z; Yao, J; Maskow, T

    2010-07-01

    The environmental fate and, in particular, biodegradation rates of hydrophobic organic compounds (HOC) are of high interest due to the ubiquity, persistence, and potential health effects of these compounds. HOC tend to interact with bioreactor materials and sampling devices and are frequently volatile, so that conventionally derived degradation parameters are often biased. We report on the development and validation of a novel calorimetric approach that serves to gain real time information on the kinetics and the physiology of HOC bioconversion in aqueous systems while overcoming weaknesses of conventional biodegradation experiments. Soil bacteria Mycobacterium frederiksbergense LB501T, Rhodococcus erythropolis K2-3 and Pseudomonas putida G7 were exposed to pulsed titrations of dissolved anthracene, 4-(2,4-dichlorophenoxy)butyric acid or naphthalene, respectively, and the thermal responses were monitored. The combinations of strains and pollutants were selected as examples for complete and partial biodegradation and complete degradation with storage product formation, respectively. Heat production signals were interpreted thermodynamically and in terms of Michaelis-Menten kinetics. The half-saturation constant k(D) and the degradation rate r(D)(Max) were derived. Comparison with conventional methods shows the suitability to extract kinetic degradation parameters of organic trace pollutants from simple ITC experiments, while thermodynamic interpretation provided further information about the metabolic fate of HOC compounds.

  9. Effect of the polarity reversal frequency in the electrokinetic-biological remediation of oxyfluorfen polluted soil.

    PubMed

    Barba, Silvia; Villaseñor, José; Rodrigo, Manuel A; Cañizares, Pablo

    2017-03-03

    This work studies the feasibility of the periodic polarity reversal strategy (PRS) in a combined electrokinetic-biological process for the remediation of clayey soil polluted with a herbicide. Five two-weeks duration electrobioremediation batch experiments were performed in a bench scale set-up using spiked clay soil polluted with oxyfluorfen (20 mg kg(-1)) under potentiostatic conditions applying an electric field between the electrodes of 1.0 V cm(-1) (20.0 V) and using PRS with five frequencies (f) ranging from 0 to 6 d(-1). Additionally, two complementary reference tests were done: single bioremediation and single electrokinetic. The microbial consortium used was obtained from an oil refinery wastewater treatment plant and acclimated to oxyfluorfen degradation. Main soil conditions (temperature, pH, moisture and conductivity) were correctly controlled using PRS. On the contrary, the electroosmotic flow clearly decreased as f increased. The uniform soil microbial distribution at the end of the experiments indicated that the microbial activity remained in every parts of the soil after two weeks when applying PRS. Despite the adapted microbial culture was capable of degrade 100% of oxyfluorfen in water, the remediation efficiency in soil in a reference test, without the application of electric current, was negligible. However, under the low voltage gradients and polarity reversal, removal efficiencies between 5% and 15% were obtained, and it suggested that oxyfluorfen had difficulties to interact with the microbial culture or nutrients and that PRS promoted transport of species, which caused a positive influence on remediation. An optimal f value was observed between 2 and 3 d(-1).

  10. Activation of peroxymonosulfate by graphitic carbon nitride loaded on activated carbon for organic pollutants degradation.

    PubMed

    Wei, Mingyu; Gao, Long; Li, Jun; Fang, Jia; Cai, Wenxuan; Li, Xiaoxia; Xu, Aihua

    2016-10-05

    Graphitic carbon nitride supported on activated carbon (g-C3N4/AC) was prepared through an in situ thermal approach and used as a metal free catalyst for pollutants degradation in the presence of peroxymonosulfate (PMS) without light irradiation. It was found that g-C3N4 was highly dispersed on the surface of AC with the increase of surface area and the exposition of more edges and defects. The much easier oxidation of C species in g-C3N4 to CO was also observed from XPS spectra. Acid Orange 7 (AO7) and other organic pollutants could be completely degraded by the g-C3N4/AC catalyst within 20min with PMS, while g-C3N4+PMS and AC+PMS showed no significant activity for the reaction. The performance of the catalyst was significantly influenced by the amount of g-C3N4 loaded on AC; but was nearly not affected by the initial solution pH and reaction temperature. In addition, the catalysts presented good stability. A nonradical mechanism accompanied by radical generation (HO and SO4(-)) in AO7 oxidation was proposed in the system. The CO groups play a key role in the process; while the exposure of more N-(C)3 group can further increase its electron density and basicity. This study can contribute to the development of green materials for sustainable remediation of aqueous organic pollutants.

  11. Behavior of pollutant-degrading microorganisms in aquifers: Predictions for genetically engineered organisms

    USGS Publications Warehouse

    Krumme, M.L.; Smith, R.L.; Egestorff, J.; Thiem, S.M.; Tiedje, J.M.; Timmis, K.N.; Dwyer, D.F.

    1994-01-01

    Bioremediation via environmental introductions of degradative microorganisms requires that the microbes survive in substantial numbers and effect an increase in the rate and extent of pollutant removal. Combined field and microcosm studies were used to assess these abilities for laboratory-grown bacteria. Following introduction into a contaminated aquifer, viable cells of Pseudomonas sp. B13 were present in the contaminant plume for 447 days; die-off was rapid in pristine areas. In aquifer microcosms, survival of B13 and FR120, a genetically engineered derivative of B13 having enhanced catabolic capabilities for substituted aromatics, was comparable to B13 field results; both bacteria degraded target pollutants in microcosms made with aquifer samples from the aerobic zone of the pollutant plume. Results suggest that field studies with nonrecombinant microorganisms may be coupled to laboratory studies with derivative strains to estimate their bioremediative efficacy. Furthermore, laboratory strains of bacteria can survive for extended periods of time in nature and thus may have important bioremediative applications. ?? 1994 American Chemical Society.

  12. Photochemical Degradation of Persistent Organic Pollutants: A Study of Ice Photochemistry Mediated by Dissolved Organic Matter

    NASA Astrophysics Data System (ADS)

    Pierce, B.; Grannas, A. M.

    2010-12-01

    Contamination and accumulation of persistent organic pollutants (POPs) in the Arctic, an area previously considered as pristine and removed from human influence, has become a growing concern. Volatile and semi-volatile contaminants from lower latitudes are transported to the Arctic through a process known as global distillation. The polar regions are unique in that they sit in darkness during the winter until polar sunrise. These conditions allow pollutants to accumulate during winter and then undergo 24-hours of continuous irradiance in sunlit conditions. Photochemical degradation may thus be an important pathway to consider in the spring/summer Arctic season. Additionally, active photochemistry has also been observed in mid-latitude snowpacks. However, the potential photodegradation of anthropogenic contaminants in mid-latitude snow has received little attention in the literature. Aldrin, a once globally distributed pesticide, is of particular environmental concern due to its low solubility in water, known persistence in the environment, and its ability to degrade into environmentally persistent products. To investigate the potential photochemical degradation of aldrin, samples of aqueous aldrin solution (20 µg/L), in liquid and frozen phases, were irradiated under Q-Panel 340 lamps to simulate the UV radiation profile of natural sunlight. Following irradiation, samples were extracted with organic solvent containing an internal standard for GC-ECD analysis. Results indicated that frozen samples degrade more quickly than liquid samples. Photochemical half lives for frozen and liquid samples were found to be approximately 13.5 hours and 45 hours respectively. It was found that the addition of natural organic matter increased the aldrin degradation rate significantly. Ongoing studies will further evaluate the differences in liquid and frozen reactivity and the influence of different sources of natural organic matter.

  13. Comparative assessment of bioremediation approaches to highly recalcitrant PAH degradation in a real industrial polluted soil.

    PubMed

    Lladó, S; Covino, S; Solanas, A M; Viñas, M; Petruccioli, M; D'annibale, A

    2013-03-15

    High recalcitrant characteristics and low bioavailability rates due to aging processes can hinder high molecular weight polycyclic aromatic hydrocarbons (HMW-PAHs) bioremediation in real industrial polluted soils. With the aim of reducing the residual fraction of total petroleum hydrocarbons (TPH) and (HMW-PAHs) in creosote-contaminated soil remaining after a 180-d treatment in a pilot-scale biopile, either biostimulation (BS) of indigenous microbial populations with a lignocellulosic substrate (LS) or fungal bioaugmentation with two strains of white-rot fungi (WRF) (i.e., Trametes versicolor and Lentinus tigrinus) were comparatively tested. The impact of bivalent manganese ions and two mobilizing agents (MAs) (i.e., Soybean Oil and Brij 30) on the degradation performances of biostimulated and bioaugmented microcosms was also compared. The results reveal soil colonization by both WRF strains was clearly hampered by an active native soil microbiota. In fact, a proper enhancement of native microbiota by means of LS amendment promoted the highest biodegradation of HMW-PAHs, even of those with five aromatic rings after 60 days of treatment, but HMW-PAH-degrading bacteria were specifically inhibited when non-ionic surfactant Brij 30 was amended. Effects of bioaugmentation and other additives such as non-ionic surfactants on the degrading capability of autochthonous soil microbiota should be evaluated in polluted soils before scaling up the remediation process at field scale.

  14. Effect of electric intensity on the microbial degradation of petroleum pollutants in soil.

    PubMed

    Li, Tingting; Guo, Shuhai; Wu, Bo; Li, Fengmei; Niu, Zhixin

    2010-01-01

    Electro-bioremediation is an innovative method to remedy organic-polluted soil. However, the principle of electrokinetic technology enhancing the function of microbes, especially the relationship of electric intensity and biodegradation efficiency, is poorly investigated. Petroleum was employed as a target organic pollutant at a level of 50 g/kg (mass of petroleum/mass of dry soil). A direct current power supply was used for tests with a constant direct current electric voltage (1.0 V/cm). The petroleum concentrations were measured at 3275-3285 nm after extraction using hexane, the group composition of crude oil was analyzed by column chromatography. The water content of soil was kept 25% (m/m). The results indicated the degradation process was divided into two periods: from day 1 to day 40, from day 41 to day 100. The treatment of soil with an appropriate electric field led the bacteria to have a persistent effect in the whole period of 100 days. The highest biodegradation efficiency of 45.5% was obtained after treatment with electric current and bacteria. The electric-bioremediation had a positive effect on alkane degradation. The degradation rate of alkane was 1.6 times higher in the soil exposed to electric current than that treated with bacteria for 100 days. A proper direct current could stimulate the microbial activities and accelerate the biodegradation of petroleum. There was a positive correlation between the electric intensities and the petroleum bioremediation efficiencies with a coefficient of 0.9599.

  15. Anodic Fenton process assisted by a microbial fuel cell for enhanced degradation of organic pollutants.

    PubMed

    Liu, Xian-Wei; Sun, Xue-Fei; Li, Dao-Bo; Li, Wen-Wei; Huang, Yu-Xi; Sheng, Guo-Ping; Yu, Han-Qing

    2012-09-15

    The electro-Fenton process is efficient for degradation of organic pollutants, but it suffers from the high operating costs due to the need of power investment. Here, a new anodic Fenton system is developed for energy-saving and efficient treatment of organic pollutants by incorporating microbial fuel cell (MFC) into an anodic Fenton process. This system is composed of an anodic Fenton reactor and a two-chamber air-cathode MFC. The power generated from a two-chamber MFC is used to drive the anodic Fenton process for Acid Orange 7 (AO7) degradation through accelerating in situ generation of Fe(2+) from sacrificial iron. The kinetic results show that the MFC-assisted anodic Fenton process system had a significantly higher pseudo-first-order rate constant than those for the chemical Fenton methods. The electrochemical analysis reveals that AO7 did not hinder the corrosion of iron. The anodic Fenton process was influenced by the MFC performance. It was also found that increasing dissolved oxygen in the cathode improved the MFC power density, which in turn enhanced the AO7 degradation rate. These clearly demonstrate that the anodic Fenton process could be integrated with MFC to develop a self-sustained system for cost-effective and energy-saving electrochemical wastewater treatment.

  16. Sonochemical degradation of the pharmaceutical fluoxetine: Effect of parameters, organic and inorganic additives and combination with a biological system.

    PubMed

    Serna-Galvis, Efraím A; Silva-Agredo, Javier; Giraldo-Aguirre, Ana L; Torres-Palma, Ricardo A

    2015-08-15

    Fluoxetine (FLX), one of the most widely used antidepressants in the world, is an emergent pollutant found in natural waters that causes disrupting effects on the endocrine systems of some aquatic species. This work explores the total elimination of FLX by sonochemical treatment coupled to a biological system. The biological process acting alone was shown to be unable to remove the pollutant, even under favourable conditions of pH and temperature. However, sonochemical treatment (600 kHz) was shown to be able to remove the pharmaceutical. Several parameters were evaluated for the ultrasound application: the applied power (20-60 W), dissolved gas (air, Ar and He), pH (3-11) and initial concentration of fluoxetine (2.9-162.0 μmol L(-1)). Additionally, the presence of organic (1-hexanol and 2-propanol) and inorganic (Fe(2+)) compounds in the water matrix and the degradation of FLX in a natural mineral water were evaluated. The sonochemical treatment readily eliminates FLX following a kinetic Langmuir. After 360 min of ultrasonic irradiation, 15% mineralization was achieved. Analysis of the biodegradability provided evidence that the sonochemical process transforms the pollutant into biodegradable substances, which can then be mineralized in a subsequent biological treatment.

  17. A previously unexposed forest soil microbial community degrades high levels of the pollutant 2,4,6-trichlorophenol.

    PubMed

    Sánchez, M A; Vásquez, M; González, B

    2004-12-01

    2,4,6-trichlorophenol (2,4,6-TCP) is a hazardous pollutant that is efficiently degraded by some aerobic soil bacterial isolates under laboratory conditions. The degradation of this pollutant in soils and its effect on the soil microbial community are poorly understood. We report here the ability of a previously unexposed forest soil microbiota to degrade high levels of 2,4,6-TCP and describe the changes in the soil microbial community found by terminal restriction fragment length polymorphism (T-RFLP) analysis. After 30 days of incubation, about 50% degradation of this pollutant was observed in soils amended with 50 to 5,000 ppm of 2,4,6-TCP. The T-RFLP analysis showed that the soil bacterial community was essentially unchanged after exposure to up to 500 ppm of 2,4,6-TCP. However, a significant decrease in richness was found with 2,000 and 5,000 ppm of 2,4,6-TCP, even though the removal of this pollutant remained high. The introduction of Ralstonia eutropha JMP134 or R. eutropha MS1, two efficient 2,4,6-TCP degraders, to this soil did not improve degradation of this pollutant, supporting the significant bioremediation potential of this previously unexposed, endogenous forest soil microbial community.

  18. [Analysis and research on the degradation and migration of organic pollutants in textile wastewater treatment process by GC-MS].

    PubMed

    Liu, Wei-jing; Zhang, Long; Wu, Wei; Tu, Yong

    2010-04-01

    In order to analyze the advantages/disadvantages of the combined treatment process between "physicochemical + biochemical" and "biochemical + physicochemical" in treatment of textile wastewater, gas chromatography-mass spectrometry (GC-MS) was used to determine the degradation process of organic pollutants in this two totally different treatment processes. The same analysis was also conducted to the sludge and discharged water. The results showed that the "physicochemical + biochemical" process displayed a poorer effect than "biochemical + physicochemical" in degrading the organic pollutants. The latter was 6.2% higher than the former in removing the organic pollutants averagely. The difference was mainly manifested in the efficiency of anaerobic hydrolysis in the two coupled processes. Moreover, the implement of "physicochemical + biochemical" process resulted in the migration of plenty of typical organic pollutants to sludge from primary coagulation sedimentation process and to the discharged water, which would cause secondary pollution easily.

  19. Appetite for danger - genetic potential for PCP degradation at historically polluted groundwater sites

    NASA Astrophysics Data System (ADS)

    Mikkonen, Anu; Yläranta, Kati; Tiirola, Marja; Romantschuk, Martin; Sinkkonen, Aki

    2016-04-01

    Pentachlorophenol (PCP) is a priority pollutant of exclusively anthropogenic origin. Formerly used commonly in timber preservatives, PCP has persisted at polluted groundwater sites decades after its use was banned, typically as the last detectable contaminant component. Notorious for its toxicity and poor biodegradability, little is known about the genetic potential and pathways for PCP degradation in the environment. The only fully characterized mineralization pathway is initiated by the enzyme coded by chromosomal pcpB gene, previously detected in PCP degrading Sphingomonadaceae bacteria isolated at two continents. However, there is no information about the abundance or diversity of any PCP degradation related gene at contaminated sites in situ. Our aim was to assess whether pcpB and/or sphingomonads seem to play a role in in situ degradation of PCP, by studying whether pcpB i) is detectable at chlorophenol-polluted groundwater sediments, ii) responds to PCP concentration changes, and iii) shows correlation with the abundance of sphingomonads or a specific sphingomonad genus. Novel protocols for quantification and profiling of pcpB, with primers covering full known diversity, were developed and tested at two sites in Finland with well-documented long-term chlorophenol contamination history: Kärkölä and Pursiala. High throughput sequencing complemented characterization of the total bacterial community and pcpB gene pool. The relative abundance of pcpB in bacterial community was associated with spatial variability in groundwater PCP concentration in Pursiala, and with temporal differences in groundwater PCP concentration in Kärkölä. T-RFLP fingerprinting results indicated and Ion Torrent PGM and Sanger sequencing confirmed the presence of a single phylotype of pcpB at both geographically distant, historically contaminated sites, matching the one detected previously in Canadian bioreactor clones and Kärkölä bioreactor isolates. Sphingomonad abundance

  20. Heterogeneous Catalysis Applied To Advanced Oxidation Processes (AOPs) For Degradation of Organic Pollutants

    NASA Astrophysics Data System (ADS)

    Cotto-Maldonado, Maria del Carmen

    Water is an essencial resource for humankind and biomes. Actually, the pollution of the water resources, specially the contamination of the fresh water is great concern in our society. Develop of new and more efficient method for degradation of pollutant in water increase the research in this area, especially in the AOPs. During this investigation a comparison between different AOPs methods (photocatalysis, sono-Fenton and photo-Fenton) to determine the most efficient process of them was done. To reach our goal, different catalysts, namely TiO2 nanowires, TiO2 CNTs, ZnO nanoparticles, Fe2O3 nanowires and magnetite nanoparticles were synthesized and characterized by different techniques including FE-SEM, TGA, specific surface area (BET), XRD, Raman spectroscopy, XPS and magnetic susceptibility. Commercial and synthesized catalysts were used in photocatalysis, sono-Fenton and photo-Fenton processes for the degradation of model organic compounds (Methylene Blue, Rhodamine B, Methyl Orange, Gential Violet, Methyl Violet and p-aminobenzoic acid). According with the experimental results, no significant differences were observed between the photo-Fenton and sono-Fenton processes when the same catalysts were used. For the photocatalytic process, the more effective catalyst was TiO2NWs and for the sono-Fenton and photo-Fenton processes, the more effective catalyst was FeCl2.

  1. Pollutional haze and COPD: etiology, epidemiology, pathogenesis, pathology, biological markers and therapy

    PubMed Central

    Wang, Fei; Ni, Song-Shi

    2016-01-01

    In recent years, serious pollutional haze occurs in the mainland of China thanks to the development of urbanization and industrialization. There is a close relationship between air pollution and the occurrence and development of chronic obstructive pulmonary disease (COPD), but there are some new characteristics in some aspects of COPD associated with pollutional haze compared with COPD induced by traditional physical and chemical factors. This article attempts to summarize the new progress from these new features of COPD related to pollutional haze, focus on etiology, epidemiology, pathogenesis, pathology, biological markers and therapy. PMID:26904250

  2. Biological and photochemical degradation of cytostatic drugs under laboratory conditions.

    PubMed

    Franquet-Griell, Helena; Medina, Andrés; Sans, Carme; Lacorte, Silvia

    2017-02-05

    Cytostatic drugs, used in chemotherapy, have emerged as new environmental contaminants due to their recurrent presence in surface waters and genotoxic effects. Yet, their degradability and environmental fate is largely unknown. The aim of this study was to determine the degradation kinetics of 16 cytostatic drugs, prioritized according to their usage and occurrence in hospital and wastewater treatment plants (WWTP) effluents, through the following laboratory scale processes: hydrolysis, aerobic biodegradation, UV-C photolysis, UV-C/H2O2 and simulated solar radiation. Some drugs were unstable in milli-Q water (vincristine, vinblastine, daunorubicin, doxorubicin and irinotecan); others were photodegraded under UV-C light (melphalan and etoposide) but some others were found to be recalcitrant to biodegradation and/or UV-C, making necessary the use of advanced oxidation processes (AOPs) such as UV-C/H2O2 for complete elimination (cytarabine, ifosfamide and cyclophosphamide). Finally, radiation in a solar box was used to simulate the fate of cytostatic drugs in surface waters under natural radiation and complete removal was not observed for any drug. The degradation process was monitored using liquid chromatography coupled to high resolution mass spectrometry and pseudo-first order kinetic degradation constants were calculated. This study provides new data on the degradability of cytostatic compounds in water, thus contributing to the existing knowledge on their fate and risk in the environment.

  3. Biologic Effects of Atmospheric Pollutants: Asbestos - The Need For and Feasibility of Air Pollution Controls

    EPA Pesticide Factsheets

    This 1971 report sets forth in a well-organized fashion the currently available information on asbestos as an air pollutant, with special attention to sources health effects, measurements, and feasibility of control.

  4. Bacteria encapsulated in layered double hydroxides: towards an efficient bionanohybrid for pollutant degradation.

    PubMed

    Halma, Matilte; Mousty, Christine; Forano, Claude; Sancelme, Martine; Besse-Hoggan, Pascale; Prevot, Vanessa

    2015-02-01

    A soft chemical process was successfully used to immobilize Pseudomonas sp. strain ADP (ADP), a well-known atrazine (herbicide) degrading bacterium, within a Mg2Al-layered double hydroxide host matrix. This approach is based on a simple, quick and ecofriendly direct coprecipitation of metal salts in the presence of a colloidal suspension of bacteria in water. It must be stressed that by this process the mass ratio between inorganic and biological components was easily tuned ranging from 2 to 40. This ratio strongly influenced the biological activity of the bacteria towards atrazine degradation. The better results were obtained for ratios of 10 or lower, leading to an enhanced atrazine degradation rate and percentage compared to free cells. Moreover the biohybrid material maintained this biodegradative activity after four cycles of reutilization and 3 weeks storage at 4°C. The ADP@MgAl-LDH bionanohybrid materials were completely characterized by X-ray diffraction (XRD), FTIR spectroscopy, thermogravimetric analysis and scanning and transmission electronic microscopy (SEM and TEM) evidencing the successful immobilization of ADP within the inorganic matrix. This synthetic approach could be readily extended to other microbial whole-cell immobilization of interest for new developments in biotechnological systems.

  5. Photochemical Degradation of Persistent Organic Pollutants: A Study of Ice Photochemistry Mediated by Dissolved Organic Matter

    NASA Astrophysics Data System (ADS)

    Bobby, R.; Pagano, L.; Grannas, A. M.

    2012-12-01

    It is well established that ice is a reactive medium in the environment and that active photochemistry occurs in frozen systems. Snow and ice contain a number of absorbing species including nitrate, peroxide and organic matter. Upon irradiation, they can generate a variety of reactive intermediates such as hydroxyl radical and singlet oxygen. It has been shown that dissolved organic matter is a ubiquitous component of snow and ice and plays an important role in overall light absorption properties of the sample. Additionally, the reactive intermediates produced can further react with contaminants present and alter their fate in the environment. Unfortunately, the role of dissolved organic matter in ice photochemistry has received little attention. Here we present results from laboratory-based studies aimed at elucidating the role of dissolved organic matter photochemistry on contaminant degradation in ice. Aqueous samples of our target pollutant, aldrin (20 μg/L), in liquid and frozen phases, were irradiated under Q-Panel 340 lamps to simulate the UV radiation profile of natural sunlight. Results indicated that frozen samples degraded more quickly than liquid samples and that the addition of dissolved organic matter increases the aldrin degradation rate significantly. Both terrestrial (Suwannee River, U.S.) and microbial sources (Pony Lake, Antarctica) of DOM were able to sensitize aldrin loss in ice. Scavengers of singlet oxygen, such as furfuryl alcohol and β-carotene, were also added to DOM solutions. Based on the type of organic matter present, the scavengers had different effects on the photochemical degradation of aldrin. Our results indicate that natural organic matter present in ice is an important component of ice photochemical processes.

  6. Highly efficient degradation of dye pollutants by Ce-doped MoO₃ catalyst at room temperature.

    PubMed

    Jin, Yujian; Li, Na; Liu, Haiqiu; Hua, Xia; Zhang, Qiuying; Chen, Mindong; Teng, Fei

    2014-09-14

    In order to efficiently degrade organic pollutants via an easily operated method, Ce-doped MoO3 (Ce(x)/MoO3) samples are synthesized by a simple impregnation method. The samples are characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), nitrogen sorption isotherms and UV-vis diffused reflectance spectra (UV-DRS), total organic carbon (TOC), infrared spectroscopy (IR) and mass spectrometry (MS) analyses. Furthermore, we have mainly investigated the degradation of different dye pollutants by the Ce(x)/MoO3 samples, including cationic methylene blue (MB), anionic methyl orange (MO), neutral phenol, and a MB-MO mixture dye. For the single-component MB and MO dyes, the highest degradation efficiencies are achieved by Ce(5)/MoO3 and Ce(10)/MoO3 samples. For the MB-MO mixture dyes, the highest degradation efficiency for MB is achieved by a Ce(10)/MoO3 sample. It is surprising that the degradation efficiency of MB in the MB-MO mixture dye solution is higher than that in the single-component MB dye solution, which has been mainly ascribed to the promoting effect of MO. Moreover, a plausible degradation mechanism of the dyes has been proposed and discussed. It should be noted that the degradation reaction is carried out at room temperature and normal atmospheric pressure, and without light irradiation. As a result, this degradation reaction is obviously different from the conventional thermally activated heterogeneous catalysis (or photocatalysis), in which thermal energy (or light irradiation) is indispensable; also different from a sorption technology, in which the pollutants cannot be degraded, but only transformed from one phase to another one. Thus, the reported degradation reaction is a quite promising environmental cleaning technology, which could be widely practically applied.

  7. Thickness-dependent photocatalytic performance of graphite oxide for degrading organic pollutants under visible light.

    PubMed

    Oh, Junghoon; Chang, Yun Hee; Kim, Yong-Hyun; Park, Sungjin

    2016-04-28

    Photocatalysts use sustainable solar light energy to trigger various catalytic reactions. Metal-free nanomaterials have been suggested as cost-effective and environmentally friendly photocatalysts. In this work, we propose thickness-controlled graphite oxide (GO) as a metal-free photocatalyst, which is produced by exfoliating thick GO particles via stirring and sonication. All GO samples exhibit photocatalytic activity for degrading an organic pollutant, rhodamine B under visible light, and the thickest sample shows the best catalytic performance. UV-vis-NIR diffuse reflectance absorption spectra indicate that thicker GO samples absorb more vis-NIR light than thinner ones. Density-functional theory calculations show that GO has a much smaller band gap than that of single-layer graphene oxide, and thus suggest that the largely-reduced band gap is responsible for this trend of light absorption.

  8. Attenuation of landfill leachate by UK Triassic sandstone aquifer materials. 2. Sorption and degradation of organic pollutants in laboratory columns

    NASA Astrophysics Data System (ADS)

    Thornton, Steven F.; Bright, Mildred I.; Lerner, David N.; Tellam, John H.

    2000-05-01

    The sorption and degradation of dissolved organic matter (DOM) and 13 organic micropollutants (BTEX, aromatic hydrocarbons, chloro-aromatic and -aliphatic compounds, and pesticides) in acetogenic and methanogenic landfill leachate was studied in laboratory columns containing Triassic sandstone aquifer materials from the English Midlands. Solute sorption and degradation relationships were evaluated using a simple transport model. Relative to predictions, micropollutant sorption was decreased up to eightfold in acetogenic leachate, but increased up to sixfold in methanogenic leachate. This behaviour reflects a combination of interactions between the micropollutants, leachate DOM and aquifer mineral fraction. Sorption of DOM was not significant. Degradation of organic fractions occurred under Mn-reducing and SO 4-reducing conditions. Degradation of some micropollutants occurred exclusively under Mn-reducing conditions. DOM and benzene were not significantly degraded under the conditions and time span (up to 280 days) of the experiments. Most micropollutants were degraded immediately or after a lag phase (32-115 days). Micropollutant degradation rates varied considerably (half-lives of 8 to >2000 days) for the same compounds (e.g., TeCE) in different experiments, and for compounds (e.g., naphthalene, DCB and TeCA) within the same experiment. Degradation of many micropollutants was both simultaneous and sequential, and inhibited by the utilisation of different substrates. This mechanism, in combination with lag phases, controls micropollutant degradation potential in these systems more than the degradation rate. These aquifer materials have a potentially large capacity for in situ bioremediation of organic pollutants in landfill leachate and significant degradation may occur in the Mn-reducing zones of leachate plumes. However, degradation of organic pollutants in acetogenic leachate may be limited in aquifers with low pH buffering capacity and reducible Mn oxides

  9. Diverse Bacterial Groups Contribute to the Alkane Degradation Potential of Chronically Polluted Subantarctic Coastal Sediments

    SciTech Connect

    Guibert, Lilian M.; Loviso, Claudia L.; Borglin, Sharon; Jansson, Janet K.; Dionisi, Hebe M.; Lozada, Mariana

    2015-11-07

    We aimed to gain insight into the alkane degradation potential of microbial communities from chronically polluted sediments of a subantarctic coastal environment using a combination of metagenomic approaches. A total of 6178 sequences annotated as alkane-1-monooxygenases (EC 1.14.15.3) were retrieved from a shotgun metagenomic dataset that included two sites analyzed in triplicate. The majority of the sequences binned with AlkB described in Bacteroidetes (32 ± 13 %) or Proteobacteria (29 ± 7 %), although a large proportion remained unclassified at the phylum level. Operational taxonomic unit (OTU)-based analyses showed small differences in AlkB distribution among samples that could be correlated with alkane concentrations, as well as with site-specific variations in pH and salinity. A number of low-abundance OTUs, mostly affiliated with Actinobacterial sequences, were found to be only present in the most contaminated samples. On the other hand, the molecular screening of a large-insert metagenomic library of intertidal sediments from one of the sampling sites identified two genomic fragments containing novel alkB gene sequences, as well as various contiguous genes related to lipid metabolism. Both genomic fragments were affiliated with the phylum Planctomycetes, and one could be further assigned to the genus Rhodopirellula due to the presence of a partial sequence of the 23S ribosomal RNA (rRNA) gene. This work highlights the diversity of bacterial groups contributing to the alkane degradation potential and reveals patterns of functional diversity in relation with environmental stressors in a chronically polluted, high-latitude coastal environment. In addition, alkane biodegradation genes are described for the first time in members of Planctomycetes.

  10. Diverse Bacterial Groups Contribute to the Alkane Degradation Potential of Chronically Polluted Subantarctic Coastal Sediments.

    PubMed

    Guibert, Lilian M; Loviso, Claudia L; Borglin, Sharon; Jansson, Janet K; Dionisi, Hebe M; Lozada, Mariana

    2016-01-01

    We aimed to gain insight into the alkane degradation potential of microbial communities from chronically polluted sediments of a subantarctic coastal environment using a combination of metagenomic approaches. A total of 6178 sequences annotated as alkane-1-monooxygenases (EC 1.14.15.3) were retrieved from a shotgun metagenomic dataset that included two sites analyzed in triplicate. The majority of the sequences binned with AlkB described in Bacteroidetes (32 ± 13 %) or Proteobacteria (29 ± 7 %), although a large proportion remained unclassified at the phylum level. Operational taxonomic unit (OTU)-based analyses showed small differences in AlkB distribution among samples that could be correlated with alkane concentrations, as well as with site-specific variations in pH and salinity. A number of low-abundance OTUs, mostly affiliated with Actinobacterial sequences, were found to be only present in the most contaminated samples. On the other hand, the molecular screening of a large-insert metagenomic library of intertidal sediments from one of the sampling sites identified two genomic fragments containing novel alkB gene sequences, as well as various contiguous genes related to lipid metabolism. Both genomic fragments were affiliated with the phylum Planctomycetes, and one could be further assigned to the genus Rhodopirellula due to the presence of a partial sequence of the 23S ribosomal RNA (rRNA) gene. This work highlights the diversity of bacterial groups contributing to the alkane degradation potential and reveals patterns of functional diversity in relation with environmental stressors in a chronically polluted, high-latitude coastal environment. In addition, alkane biodegradation genes are described for the first time in members of Planctomycetes.

  11. Biological risk and pollution history of polycyclic aromatic hydrocarbons (PAHs) in Nansha mangrove, South China.

    PubMed

    Wu, Qihang; Leung, Jonathan Y S; Tam, Nora F Y; Chen, Shejun; Mai, Bixian; Zhou, Xizhen; Xia, Lihua; Geng, Xinhua

    2014-08-15

    Chinese government has taken various measures to alleviate pollution caused by polycyclic aromatic hydrocarbons (PAHs) in the region of Pearl River Delta since the economic reform in 1978, but the effectiveness of these measures remains largely unknown. This study aimed to elucidate the biological risk and pollution history of PAHs by measuring the concentrations of 28 PAHs in the surface and core sediments, respectively, in Nansha mangrove. Results found that the biological risk of PAHs was low without obvious spatial variation. The PAH concentration along the depth gradient indicated that PAH pollution was stabilized since the early 1990s while the source of PAHs has gradually changed from combustion of coal to petroleum products. This implied that the mitigation measures taken by the Chinese government were effective. Compared to marine bottom sediment, we propose that using mangrove sediment can provide a more accurate and precise estimate of pollution history of PAHs.

  12. Enhancement of in vitro high-density polyethylene (HDPE) degradation by physical, chemical, and biological treatments.

    PubMed

    Balasubramanian, V; Natarajan, K; Rajeshkannan, V; Perumal, P

    2014-11-01

    Partially degraded high-density polyethylene (HDPE) was collected from plastic waste dump yard for biodegradation using fungi. Of various fungi screened, strain MF12 was found efficient in degrading HDPE by weight loss and Fourier transform infrared (FT-IR) spectrophotometric analysis. Strain MF12 was selected as efficient HDPE degraders for further studies, and their growth medium composition was optimized. Among those different media used, basal minimal medium (BMM) was suitable for the HDPE degradation by strain MF12. Strain MF12 was subjected to 28S rRNA sequence analysis and identified as Aspergillus terreus MF12. HDPE degradation was carried out using combinatorial physical and chemical treatments in conjunction to biological treatment. The high level of HDPE degradation was observed in ultraviolet (UV) and KMnO4/HCl with A. terreus MF12 treatment, i.e., FT10. The abiotic physical and chemical factors enhance the biodegradation of HDPE using A. terreus MF12.

  13. Degradation of methylene blue using biologically synthesized silver nanoparticles.

    PubMed

    Vanaja, M; Paulkumar, K; Baburaja, M; Rajeshkumar, S; Gnanajobitha, G; Malarkodi, C; Sivakavinesan, M; Annadurai, G

    2014-01-01

    Nowadays plant mediated synthesis of nanoparticles has great interest and achievement due to its eco-benign and low time consuming properties. In this study silver nanoparticles were successfully synthesized by using Morinda tinctoria leaf extract under different pH. The aqueous leaf extract was added to silver nitrate solution; the color of the reaction medium was changed from pale yellow to brown and that indicates reduction of silver ions to silver nanoparticles. Thus synthesized silver nanoparticles were characterized by UV-Vis spectrophotometer. Dispersity and morphology was characterized by scanning electron microscope (SEM); crystalline nature and purity of synthesized silver nanoparticles were revealed by X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX). FTIR spectrum was examined to identify the effective functional molecules responsible for the reduction and stabilization of silver nanoparticles synthesized by leaf extract. The photocatalytic activity of the synthesized silver nanoparticles was examined by degradation of methylene blue under sunlight irradiation. Green synthesized silver nanoparticles were effectively degrading the dye nearly 95% at 72 h of exposure time.

  14. Piezo impedance sensors to monitor degradation of biological structure

    NASA Astrophysics Data System (ADS)

    Annamdas, Kiran Kishore Kumar; Annamdas, Venu Gopal Madhav

    2010-04-01

    In some countries it is common to have wooden structures in their homes, especially Japan. However, metals and its alloys are the most widely used engineering materials in construction of any military or civil structure. Re-visiting natural disasters like the recent Haiti earthquake (12 Jan 2010) or Katrina (cyclones) reminds the necessity to have better housing infrastructure with robust monitoring systems. Traditionally wood (green material) was accepted as excellent rehabilitation material, after any disaster. In recent times, the recycling materials extracted from inorganic, biodegradable wastes are converted into blocks or sheets, and are also used to assist public in rehabilitation camps. The key issue which decreases the life of these rehabilitated structure including green materials (like wood) is unnecessary degradation or deterioration over time due to insect or acid attack or rain/ice fall. The recycling material also needs monitoring to protect them against acid or rain/ice attacks. Thus, a few health monitoring techniques have emerged in the recent past. Electromechanical Impedance technique is one such technique, which is simple but robust to detect variations in the integrity of structures. In this paper, impedance based piezoceramic sensor was bonded on wooden sample, which was subjected to degradation in presence of acids. Variations in mass of plank are studied.

  15. Degradation of Methylene Blue Using Biologically Synthesized Silver Nanoparticles

    PubMed Central

    Vanaja, M.; Paulkumar, K.; Baburaja, M.; Rajeshkumar, S.; Gnanajobitha, G.; Malarkodi, C.; Sivakavinesan, M.; Annadurai, G.

    2014-01-01

    Nowadays plant mediated synthesis of nanoparticles has great interest and achievement due to its eco-benign and low time consuming properties. In this study silver nanoparticles were successfully synthesized by using Morinda tinctoria leaf extract under different pH. The aqueous leaf extract was added to silver nitrate solution; the color of the reaction medium was changed from pale yellow to brown and that indicates reduction of silver ions to silver nanoparticles. Thus synthesized silver nanoparticles were characterized by UV-Vis spectrophotometer. Dispersity and morphology was characterized by scanning electron microscope (SEM); crystalline nature and purity of synthesized silver nanoparticles were revealed by X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX). FTIR spectrum was examined to identify the effective functional molecules responsible for the reduction and stabilization of silver nanoparticles synthesized by leaf extract. The photocatalytic activity of the synthesized silver nanoparticles was examined by degradation of methylene blue under sunlight irradiation. Green synthesized silver nanoparticles were effectively degrading the dye nearly 95% at 72 h of exposure time. PMID:24772055

  16. Au-decorated sodium titanate nanotubes as high-performance selective photocatalysts for pollutant degradation

    NASA Astrophysics Data System (ADS)

    El Rouby, Waleed M. A.; Comesaña-Hermo, Miguel; Testa-Anta, Martín; Carbó-Argibay, Enrique; Salgueiriño, Verónica; Pérez-Lorenzo, Moisés; Correa-Duarte, Miguel A.

    2017-04-01

    The bioaccumulation of polycyclic aromatic compounds originating from textile processing industries is nowadays a major environmental problem worldwide. In order to tackle this situation, several inorganic semiconductors have been tested as photocatalysts for the degradation of these harmful pollutants in the search of sustainable and cost-effective solutions. Nevertheless, these semiconductor materials often involve important limitations, such as poor efficiency and selectivity, which, in the end, substantially restrict their implementation at the industrial scale. As an alternative, we herein report the fabrication and application of Au-decorated titanate nanotubes (TNTs) as high-performance architectures for the selective degradation of organic contaminants. This synthetic strategy is intended to establish a synergetic integration of the physicochemical and photocatalytic features of these hybrid nanostructures, by combining the remarkable adsorption capabilities of TNTs with the enhanced light-harvesting efficiency provided by the incorporation of a noble metal component. The obtained results evidence the great potential that rationally designed plasmonic composites may have for the development of selective environmental remediation technologies and in particular on the current challenges faced by the wastewater treatment sector.

  17. Potential of the hydrothermal carbonization process for the degradation of organic pollutants.

    PubMed

    Weiner, Barbara; Baskyr, Igor; Poerschmann, Jürgen; Kopinke, Frank-Dieter

    2013-07-01

    The degree of degradation of 12 organic compounds from various classes, comprising of pharmaceuticals, pesticides, and industrial chemicals, was analyzed after hydrothermal treatment at 200°C for 4 or 16h, or 255°C for 16h. The reactions were conducted in water, aqueous H2SO4, or sucrose solution in aqueous H2SO4 as a representative matrix of hydrothermal carbonization (HTC) of wet biomasses. The impact of the sucrose-matrix, which formed during the HTC reaction as a solid hydrochar material and a complex pattern of dissolved organic matter in the aqueous phase, was found to be insignificant for the degree of conversion of most compounds. On the contrary, the degree of degradation of 2,6-dinitrotoluene, 2-chloronaphthalene and 3-chlorobiphenyl was enhanced when biomass was present. At high temperatures most of the pollutants were converted except for ibuprofen and chlorinated aromatics. Hydrothermal treatment of β-hexachlorocyclohexane and 4,4'-dichlorodiphenyltrichloroethane led to the formation of stable chlorinated aromatic intermediates.

  18. Highly Efficient Photocatalysts and Continuous-Flow Photocatalytic Reactors for Degradation of Organic Pollutants in Wastewater.

    PubMed

    Chang, Sujie; Yang, Xiaoqiu; Sang, Yuanhua; Liu, Hong

    2016-09-06

    One of the most important applications for photocatalysis is engineered water treatment that photodegrades organic pollutants in wastewater at low cost. To overcome the low efficiency of batch degradation methods, continuous-flow photocatalytic reactors have been proposed and have become the most promising method for mass water treatment. However, most commercial semiconductor photocatalysts are granular nanoparticles with low activity and a narrow active light wavelength band; this creates difficulties for direct use in continuous-flow photocatalytic reactors. Therefore, a high-performance photodegradation photocatalyst with proper morphology or structure is key for continuous photocatalytic degradation. Moreover, a well-designed photocatalytic device is another important component for continuous-flow photocatalysis and determines the efficiency of photocatalysis in practical water treatment. This review describes the basic design principles and synthesis of photocatalysts with excellent performance and special morphologies suitable for a filtering photocatalysis process. Certain promising continuous photodegradation reactors are also categorized and summarized. Additionally, selected scientific and technical problems that must be urgently solved are suggested.

  19. Structuring β-Ga2O3 photonic crystal photocatalyst for efficient degradation of organic pollutants.

    PubMed

    Li, Xiaofang; Zhen, Xiuzheng; Meng, Sugang; Xian, Jiangjun; Shao, Yu; Fu, Xianzhi; Li, Danzhen

    2013-09-03

    Coupling photocatalysts with photonic crystals structure is based on the unique property of photonic crystals in confining, controlling, and manipulating the incident photons. This combination enhances the light absorption in photocatalysts and thus greatly improves their photocatalytic performance. In this study, Ga2O3 photonic crystals with well-arranged skeleton structures were prepared via a dip-coating infiltration method. The positions of the electronic band absorption for Ga2O3 photonic crystals could be made to locate on the red edge, on the blue edge, and away from the edge of their photonic band gaps by changing the pore sizes of the samples, respectively. Particularly, the electronic band absorption of the Ga2O3 photonic crystal with a pore size of 135 nm was enhanced more than other samples by making it locate on the red edge of its photonic band gap, which was confirmed by the higher instantaneous photocurrent and photocatalytic activity for the degradation of various organic pollutants under ultraviolet light irradiation. Furthermore, the degradation mechanism over Ga2O3 photonic crystals was discussed. The design of Ga2O3 photonic crystals presents a prospective application of photonic crystals in photocatalysis to address light harvesting and quantum efficiency problems through manipulating photons or constructing photonic crystal structure as groundwork.

  20. Graphitic carbon nitride induced activity enhancement of OMS-2 catalyst for pollutants degradation with peroxymonosulfate

    NASA Astrophysics Data System (ADS)

    Li, Jun; Fang, Jia; Gao, Long; Zhang, Jingwen; Ruan, Xinchao; Xu, Aihua; Li, Xiaoxia

    2017-04-01

    Low valent manganese species and surface oxygen vacancies in OMS-2 play an important role in catalytic reactions, and it is highly desirable and challenging to develop a feasible strategy of increasing the Mn(II) and Mn(III) species concentration in the oxide. Herein, the OMS-2/g-C3N4 hybrids (OMS-2/CN) were prepared by a facile refluxing approach. It was found that the MnOx precursor from the reaction of KMnO4 and MnSO4 was transformed into OMS-2 nanofibers with the formation of more Mn(II) and Mn(III) species in OMS-2 and the destruction and oxidation of g-C3N4. The hybrids exhibited higher efficiency for pollutants degradation in the presence of PMS than the pure OMS-2 or g-C3N4. There was a linear correlation between the specific initial rate and the ratio of Mn(II + III)/Mn(IV). Mechanism investigation indicated that high active manganese species or caged radicals were produced through the oxidation of Mn(II) and Mn(III) by PMS and contributed to the degradation reaction. During five consecutive cycles, the catalyst exhibited good reusability and stability. Therefore, the OMS-2/CN hybrids are promising catalysts for wastewater treatment with PMS as the oxidant.

  1. Use of Copper Oxide Nanoparticles for the Oxidative Degradation of Persistent Organic Water Pollutants

    NASA Astrophysics Data System (ADS)

    Dror, I.; Ben Moshe, T.; Berkowitz, B.

    2008-12-01

    The continuous release of persistent organic chemicals such as pesticides, halogenated organic solvents, PAHs, and PCBs to the subsurface environment is an unfortunate reality. These compounds are recognized as toxic, and often carcinogenic and/or mutagenic, and they thus require highly efficient treatment procedures in aqueous systems. The current study presents an oxidation process, to decontaminate polluted water, using nanosized copper oxide particles as the catalyst and hydrogen peroxide as the oxidation agent. The process shows complete and rapid degradation of a wide range of organic contaminants under ambient pressure and temperature. In contrast, control runs that measured the degradation through exposure to hydrogen peroxide only or copper oxide nanoparticles only showed less than 10% reduction in contaminant concentration, as compared to the complete degradation achieved when particles and oxidation agent were used. Lack of exposure to light and the method of mixing seem to have no influence on the reaction rate or products. The reaction was found to proceed effectively in the range pH 3-8.5, and much slower at pH 10. Testing various concentrations of oxidation agent, an optimum point was found, with an increase above this concentration resulting in a reduced reaction rate. Moreover, measurements of reaction kinetics demonstrated a conversion from exponential decay of a contaminant, typical of a first-order reaction, to a linear decrease in contaminant concentration which is typical of a pseudo-zero-order reaction. This behavior indicates that upon increase in oxidation agent concentration, a different reaction pathway which is independent of the contaminant concentration becomes the prevailing process. The copper oxide nanoparticles were characterized before and after the reaction, and also shown to retain reactivity for several cycles after refreshing the contaminant solution and adding more hydrogen peroxide.

  2. In vivo degradation of 14C-labeled porcine dermis biologic scaffold

    PubMed Central

    Carey, Lisa E.; Dearth, Christopher L.; Johnson, Scott A.; Londono, Ricardo; Medberry, Christopher J.; Daly, Kerry A.; Badylak, Stephen F.

    2017-01-01

    Biologic scaffold materials are used for repair and reconstruction of injured or missing tissues. Such materials are often composed of allogeneic or xenogeneic extracellular matrix (ECM) manufactured by decellularization of source tissue, such as dermis. Dermal ECM (D-ECM) has been observed to degrade and remodel in vivo more slowly than other biologic scaffold materials, such as small intestinal submucosa (SIS-ECM). Histologic examination is a common method for evaluating material degradation, but it lacks sensitivity and is subject to observer bias. Utilization of 14C-proline labeled ECM is a quantitative alternative for measuring degradation of ECM scaffolds. Using both methods, the amount of degradation of D-ECM and SIS-ECM was determined at 2, 4, and 24 weeks post-implantation in a rodent model. Results utilizing 14C liquid scintillation counting (LSC) analysis showed distinct differences in degradation at the three time points. D-ECM material in situ stayed the same at 76% remaining from 2 to 4 weeks post-implantation, and then decreased to 44% remaining at 24 weeks. In the same time period, implanted SIS-ECM material decreased from 72% to 13% to 0%. Visual examination of device degradation by histology overestimated degradation at 2 weeks and underestimated device degradation at 24 weeks, compared to the 14C method. PMID:24997479

  3. Photocatalytic degradation of bezacryl yellow in batch reactors--feasibility of the combination of photocatalysis and a biological treatment.

    PubMed

    Khenniche, Lamia; Favier, Lidia; Bouzaza, Abdelkrim; Fourcade, Florence; Aissani, Farida; Amrane, Abdeltif

    2015-01-01

    A combined process coupling photocatalysis and a biological treatment was investigated for the removal of Bezacryl yellow (BZY), an industrial-use textile dye. Photocatalytic degradation experiments of BZY were carried out in two stirred reactors, operating in batch mode with internal or external irradiation. Two photocatalysts (TiO2P25 and TiO2PC500) were tested and the dye degradation was studied for different initial pollutant concentrations (10-117 mg L(-1)). A comparative study showed that the photocatalytic degradation led to the highest degradation and mineralization yields in a stirred reactor with internal irradiation in the presence of the P25 catalyst. Regardless of the photocatalyst, discoloration yields up to 99% were obtained for 10 and 20 mg L(-1) dye concentrations in the reactor with internal irradiation. Moreover, the first-order kinetic and Langmuir-Hinshelwood models were examined by using the nonlinear method for different initial concentrations and showed that the two models lead to completely different predicted kinetics suggesting that they were completely different.According to the BOD5/ Chemical oxygen demand (COD) ratio, the non-treated solution (20 mg L(-1) of BZY) was estimated as non-biodegradable. After photocatalytic pretreatment of bezacryl solution containing 20 mg/L of initial dye, the biodegradability test showed a BOD5/COD ratio of 0.5, which is above the limit of biodegradability (0.4). These results were promising regarding the feasibility of combining photocatalysis and biological mineralization for the removal of BZY.

  4. Nanomaterial based detection and degradation of biological and chemical contaminants in a microfluidic system

    NASA Astrophysics Data System (ADS)

    Jayamohan, Harikrishnan

    Monitoring and remediation of environmental contaminants (biological and chemical) form the crux of global water resource management. There is an extant need to develop point-of-use, low-power, low-cost tools that can address this problem effectively with minimal environmental impact. Nanotechnology and microfluidics have made enormous advances during the past decade in the area of biosensing and environmental remediation. The "marriage" of these two technologies can effectively address some of the above-mentioned needs. In this dissertation, nanomaterials were used in conjunction with microfluidic techniques to detect and degrade biological and chemical pollutants. In the first project, a point-of-use sensor was developed for detection of trichloroethylene (TCE) from water. A self-organizing nanotubular titanium dioxide (TNA) synthesized by electrochemical anodization and functionalized with photocatalytically deposited platinum (Pt/TNA) was applied to the detection. The morphology and crystallinity of the Pt/TNA sensor was characterized using field emission scanning electron microscope, energy dis- persive x-ray spectroscopy, and X-ray diffraction. The sensor could detect TCE in the concentrations ranging from 10 to 1000 ppm. The room-temperature operation capability of the sensor makes it less power intensive and can potentially be incorporated into a field-based sensor. In the second part, TNA synthesized on a foil was incorporated into a flow-based microfluidic format and applied to degradation of a model pollutant, methylene blue. The system was demonstrated to have enhanced photocatalytic performance at higher flow rates (50-200 muL/min) over the same microfluidic format with TiO2 nanoparticulate (commercial P25) catalyst. The microfluidic format with TNA catalyst was able to achieve 82% fractional conversion of 18 mM methylene blue in comparison to 55% in the case of the TiO2 nanoparticulate layer at a flow rate of 200 L/min. The microfluidic device was

  5. Degradation of trace concentrations of the persistent groundwater pollutant 2,6-dichlorobenzamide (BAM) in bioaugmented rapid sand filters.

    PubMed

    Albers, Christian Nyrop; Feld, Louise; Ellegaard-Jensen, Lea; Aamand, Jens

    2015-10-15

    Groundwater is an important drinking water resource. Yet, this resource is threatened by pollution from chemicals, such as pesticides and their degradation products. To investigate the potential for remediation of groundwater polluted by trace concentrations of the pesticide residue 2,6-dichlorobenzamide (BAM), we established a pilot waterworks including two sand filters. The waterworks treated groundwater polluted with 0.2 μg/L BAM at flow conditions typical for rapid sand filters. Bioaugmentation of the sand filter with a specific BAM-degrading bacterium (Aminobacter sp. MSH1) resulted in significant BAM degradation to concentrations below the legal threshold level (0.1 μg/L), and this without adverse effects on other sand filter processes such as ammonium and iron oxidation. However, efficient degradation for more than 2-3 weeks was difficult to maintain due to loss of MSH1-bacteria, especially during backwashing. By limiting backwash procedures, the period of degradation was prolonged, but bacteria (and hence degradation activity) were still lost with time. Protozoa were observed to grow in the filters to a density that contributed significantly to the general loss of bacteria from the filters. Additionally, the concentration of easily assimilable organic carbon (AOC) in the remediated water may have been too low to sustain a sufficient population of degrader bacteria in the filter. This study shows that scaling up is not trivial and shortcomings in transferring degradation rates obtained in batch experiments to a rapid sand filter system are discussed. Further optimization is necessary to obtain and control more temporally stable systems for water purification. However, for the first time outside the laboratory and at realistic conditions a potential for the biodegradation of recalcitrant micropollutants in bioaugmented rapid sand filters is shown.

  6. Isolation of an endosulfan-degrading bacterium from a coffee farm soil: persistence and inhibitory effect on its biological functions.

    PubMed

    Castillo, Jean Manuel; Casas, Jaime; Romero, Esperanza

    2011-12-15

    Endosulfan is a lypophilic persistent organic pollutant (POP) that has caused widespread concern due to its persistence in the environment, toxicity and bioaccumulation in living organisms. The aim of this study is to isolate endosulfan-degrading bacteria taken from five coffee farms historically exposed to this insecticide which could be used in future remediation strategies. The biodegradation capability of the isolated strain as well as endosulfan's impact on some of the strain's biological functions was studied. Endosulfan and its metabolites were analyzed using TLC and GC-MS. The isolated strain, capable of growing in a liquid culture treated with this insecticide as the sole sulfur source rather than a carbon source, was selected for further study. The isolated bacterium is Gram-negative, having the morphological and biochemical characteristics of Azotobacter sp. The remaining concentrations after 6 days, using 2 and 10 mg l(-1) of endosulfan, were 57.6 and 72.3% respectively, and the degradation constants were 0.12 d(-1) and 0.26 d(-1). Four metabolites were detected, one of which was identified as endosulfan ether. Endosulfan reduced nitrogenase activity but had no impact on indole 3-acetic acid production. Thus, these results suggest that this strain has the potential to act as a biocatalyst in endosulfan degradation.

  7. Particulate pollutants are capable to 'degrade' epicuticular waxes and to decrease the drought tolerance of Scots pine (Pinus sylvestris L.).

    PubMed

    Burkhardt, Juergen; Pariyar, Shyam

    2014-01-01

    Air pollution causes the amorphous appearance of epicuticular waxes in conifers, usually called wax 'degradation' or 'erosion', which is often correlated with tree damage symptoms, e.g., winter desiccation. Previous investigations concentrated on wax chemistry, with little success. Here, we address the hypothesis that both 'wax degradation' and decreasing drought tolerance of trees may result from physical factors following the deposition of salt particles onto the needles. Pine seedlings were sprayed with dry aerosols or 50 mM solutions of different salts. The needles underwent humidity changes within an environmental scanning electron microscope, causing salt expansion on the surface and into the epistomatal chambers. The development of amorphous wax appearance by deliquescent salts covering tubular wax fibrils was demonstrated. The minimum epidermal conductance of the sprayed pine seedlings increased. Aerosol deposition potentially 'degrades' waxes and decreases tree drought tolerance. These effects have not been adequately considered thus far in air pollution research.

  8. Epidemiology of fine particulate air pollution and human health: biologic mechanisms and who's at risk?

    PubMed Central

    Pope, C A

    2000-01-01

    This article briefly summarizes the epidemiology of the health effects of fine particulate air pollution, provides an early, somewhat speculative, discussion of the contribution of epidemiology to evaluating biologic mechanisms, and evaluates who's at risk or is susceptible to adverse health effects. Based on preliminary epidemiologic evidence, it is speculated that a systemic response to fine particle-induced pulmonary inflammation, including cytokine release and altered cardiac autonomic function, may be part of the pathophysiologic mechanisms or pathways linking particulate pollution with cardiopulmonary disease. The elderly, infants, and persons with chronic cardiopulmonary disease, influenza, or asthma are most susceptible to mortality and serious morbidity effects from short-term acutely elevated exposures. Others are susceptible to less serious health effects such as transient increases in respiratory symptoms, decreased lung function, or other physiologic changes. Chronic exposure studies suggest relatively broad susceptibility to cumulative effects of long-term repeated exposure to fine particulate pollution, resulting in substantive estimates of population average loss of life expectancy in highly polluted environments. Additional knowledge is needed about the specific pollutants or mix of pollutants responsible for the adverse health effects and the biologic mechanisms involved. PMID:10931790

  9. The "degradative" and "biological" pumps controls on the atmospheric deposition and sequestration of hexachlorocyclohexanes and hexachlorobenzene in the North Atlantic and Arctic Oceans.

    PubMed

    Galbán-Malagón, Cristóbal J; Berrojalbiz, Naiara; Gioia, Rosalinda; Dachs, Jordi

    2013-07-02

    The cycling of hexachlorobenzene (HCB) and hexachlorocyclohexanes (HCHs) has been studied in the North Atlantic and Arctic Ocean. Concentrations of HCHs and HCB were measured simultaneously in the atmosphere (gas and aerosol phases), seawater (dissolved and particulate phases), and phytoplankton. The atmospheric concentrations of HCHs decrease during transport over the Greenland Current with estimated e-folding times of 1.6 days, a trend not observed for HCB. This strong decrease in atmospheric concentrations of HCH is consistent with the estimated atmospheric depositional fluxes driven by the air-water disequilibrium. The removal of HCHs from the surface ocean by the degradative pump due to hydrolysis and microbial degradation and by the biological pump due to settling of particle-associated HCHs are estimated; the removal fluxes are within a factor of 2 of the atmospheric inputs for most sampling events, suggesting an important role of the degradative pump in the overall oceanic sink of HCHs. Conversely, the lack of degradation of HCB in surface waters and its relatively low hydrophobicity imply a lack of effective removal processes, consistent with the observed air and water concentrations close to equilibrium. This work is the first that estimates the relative importance of the biological and degradative pumps on the atmospheric deposition of the less persistent organic pollutants and points out the need for further research for quantifying the magnitude of degradative processes in the environment.

  10. The Complete Multipartite Genome Sequence of Cupriavidus necator JMP134, a Versatile Pollutant Degrader

    SciTech Connect

    Lykidis, Athanasios; Perez-Pantoja, Danilo; Ledger, Thomas; Mavromatis, Kostantinos; Anderson, Iain J.; Ivanova, Natalia N.; Hooper, Sean D.; Lapidus, Alla; Lucas, Susan; Gonzalez, Bernardo; Kyrpides, Nikos C.

    2010-02-01

    Cupriavidus necator JMP134 (formerly Ralstonia eutropha JMP134) is a Gram-negative {beta}-proteobacterium able to degrade a variety of chloroaromatic compounds and chemically-related pollutants. It was originally isolated based on its ability to use 2,4 dichlorophenoxyacetic acid (2,4-D) as a sole carbon and energy source [1]. In addition to 2,4-D, this strain can also grow on a variety of aromatic substrates, such as 4-chloro-2-methylphenoxyacetate (MCPA), 3-chlorobenzoic acid (3-CB) [2], 2,4,6-trichlorophenol [3], and 4-fluorobenzoate [4]. The genes necessary for 2,4-D utilization have been identified. They are located in two clusters on plasmid pPJ4: tfd{sub I} and tfd{sub II} [5,6,7,8]. The sequence and analysis of plasmid pJP4 was reported and a congruent model for bacterial adaptation to chloroaromatic pollutants was proposed [9]. According to this model, catabolic gene clusters assemble in a modular manner into broad-host-range plasmid backbones by means of repeated chromosomal capture events. Cupriavidus and related Burkholderia genomes are typically multipartite, composed of two large replicons (chromosomes) accompanied by classical plasmids. Previous work with Burkholderia xenovorans LB400 revealed a differential gene distribution with core functions preferentially encoded by the larger chromosome and secondary functions by the smaller [10]. It has been proposed that the secondary chromosomes in many bacteria originated from ancestral plasmids which, in turn, had been the recipient of genes transferred earlier from ancestral primary chromosomes [11]. The existence of multiple Cupriavidus and Burkholderia genomes provides the opportunity for comparative studies that will lead to a better understanding of the evolutionary mechanisms for the formation of multipartite genomes and the relation with biodegradation abilities.

  11. In Situ Photochemical Activation of Sulfate for Enhanced Degradation of Organic Pollutants in Water.

    PubMed

    Liu, Guoshuai; You, Shijie; Tan, Yang; Ren, Nanqi

    2017-02-21

    The advanced oxidation process (AOP) based on SO4(•-) radicals has been receiving growing attention in water and wastewater treatment. Producing SO4(•-) radicals by activation of peroxymonosulfate or persulfate faces the challenges of high operational cost and potential secondary pollution. In this study, we report the in situ photochemical activation of sulfate (i-PCAS) to produce SO4(•-) radicals with bismuth phosphate (BPO) serving as photocatalyst. The prepared BPO rod-like material could achieve remarkably enhanced degradation of 2,4-dichlorophenol (2,4-DCP) in the presence of sulfate, indicated by the first-order kinetic constant (k = 0.0402 min(-1)) being approximately 2.1 times that in the absence (k = 0.019 min(-1)) at pH-neutral condition. This presented a marked contrast with commercial TiO2 (P25), the performance of which was always inhibited by sulfate. The impact of radical scavenger and electrolyte, combined with electron spin resonance (ESR) measurement, verified the formation of •OH and SO4(•-) radicals during i-PCAS process. According to theoretical calculations, BPO has a sufficiently high valence band potential making it thermodynamically favorable for sulfate oxidation, and weaker interaction with SO4(•-) radicals resulting in higher reactivity toward target organic pollutant. The concept of i-PCAS appears to be attractive for creating new photochemical systems where in situ production of SO4(•-) radicals can be realized by using sulfate originally existing in aqueous environment. This eliminates the need for extrinsic chemicals and pH adjustment, which makes water treatment much easier, more economical, and more sustainable.

  12. Degradation alternatives for a commercial fungicide in water: biological, photo-Fenton, and coupled biological photo-Fenton processes.

    PubMed

    López-Loveira, Elsa; Ariganello, Federico; Medina, María Sara; Centrón, Daniela; Candal, Roberto; Curutchet, Gustavo

    2016-09-17

    Imazalil (IMZ) is a widely used fungicide for the post-harvest treatment of citrus, classified as "likely to be carcinogenic in humans" for EPA, that can be only partially removed by conventional biological treatment. Consequently, specific or combined processes should be applied to prevent its release to the environment. Biological treatment with adapted microorganism consortium, photo-Fenton, and coupled biological photo-Fenton processes were tested as alternatives for the purification of water containing high concentration of the fungicide and the coadjutants present in the commercial formulation. IMZ-resistant consortium with the capacity to degrade IMZ in the presence of a C-rich co-substrate was isolated from sludge coming from a fruit packaging company wastewater treatment plant. This consortium was adapted to resist and degrade the organics present in photo-Fenton-oxidized IMZ water solution. Bacteria colonies from the consortia were isolated and identified. The effect of H2O2 initial concentration and dosage on IMZ degradation rate, average oxidation state (AOS), organic acid concentration, oxidation, and mineralization percentage after photo-Fenton process was determined. The application of biological treatment to the oxidized solutions notably decreased the total organic carbon (TOC) in solution. The effect of the oxidation degree, limited by H2O2 concentration and dosage, on the percentage of mineralization obtained after the biological treatment was determined and explained in terms of changes in AOS. The concentration of H2O2 necessary to eliminate IMZ by photo-Fenton and to reduce TOC and chemical oxygen demand (COD) by biological treatment, in order to allow the release of the effluents to rivers with different flows, was estimated.

  13. Influence of earthworm activity on microbial communities related with the degradation of persistent pollutants.

    PubMed

    Natal-da-Luz, Tiago; Lee, Iwa; Verweij, Rudo A; Morais, Paula V; Van Velzen, Martin J M; Sousa, José Paulo; Van Gestel, Cornelis A M

    2012-04-01

    Earthworms may promote the biodegradation of polycyclic aromatic hydrocarbons (PAHs) in soil, but the mechanism through which they exert such influence is still unknown. To determine if the stimulation of PAH degradation by earthworms is related to changes in microbial communities, a microcosm experiment was conducted consisting of columns with natural uncontaminated soil covered with PAH-contaminated dredge sediment. Columns without and with low and high Eisenia andrei densities were prepared. Organic matter and PAH content, microbial biomass, and dehydrogenase activity (DHA) were measured in soil and sediment over time. Biolog Ecoplate™ and polymerase chain reaction using denaturing gradient gel electrophoresis were used to evaluate changes in metabolic and structural diversity of the microbial community, respectively. Earthworm activity promoted PAH degradation in soil, which was significant for biphenyl, benzo[a]pyrene, and benzo[e]pyrene. Microbial biomass and DHA activity generally did not change over the experiment. Earthworm activity did change microbial community structure, but this did not affect its functioning in terms of carbon substrate consumption. Results suggest no relationship between changes in the microbial community by earthworm activity and increased PAH disappearance. The role of shifts in soil microbial community structure induced by earthworms in PAH removal needs further investigation.

  14. Current Status on Biochemistry and Molecular Biology of Microbial Degradation of Nicotine

    PubMed Central

    Gurusamy, Raman; Natarajan, Sakthivel

    2013-01-01

    Bioremediation is one of the most promising methods to clean up polluted environments using highly efficient potent microbes. Microbes with specific enzymes and biochemical pathways are capable of degrading the tobacco alkaloids including highly toxic heterocyclic compound, nicotine. After the metabolic conversion, these nicotinophilic microbes use nicotine as the sole carbon, nitrogen, and energy source for their growth. Various nicotine degradation pathways such as demethylation pathway in fungi, pyridine pathway in Gram-positive bacteria, pyrrolidine pathway, and variant of pyridine and pyrrolidine pathways in Gram-negative bacteria have been reported. In this review, we discussed the nicotine-degrading pathways of microbes and their enzymes and biotechnological applications of nicotine intermediate metabolites. PMID:24470788

  15. Long-term exposure to air pollution is associated with biological aging

    PubMed Central

    Ward-Caviness, Cavin K.; Nwanaji-Enwerem, Jamaji C.; Wolf, Kathrin; Wahl, Simone; Colicino, Elena; Trevisi, Letizia; Kloog, Itai; Just, Allan C.; Vokonas, Pantel; Cyrys, Josef; Gieger, Christian; Schwartz, Joel; Baccarelli, Andrea A.; Schneider, Alexandra; Peters, Annette

    2016-01-01

    Long-term exposure to air pollution is associated with age-related diseases. We explored the association between accelerated biological aging and air pollution, a potential mechanism linking air pollution and health. We estimated long-term exposure to PM10, PM2.5, PM2.5 absorbance/black carbon (BC), and NOx via land-use regression models in individuals from the KORA F4 cohort. Accelerated biological aging was assessed using telomere length (TeloAA) and three epigenetic measures: DNA methylation age acceleration (DNAmAA), extrinsic epigenetic age acceleration (correlated with immune cell counts, EEAA), and intrinsic epigenetic age acceleration (independent of immune cell counts, IEAA). We also investigated sex-specific associations between air pollution and biological aging, given the published association between sex and aging measures. In KORA an interquartile range (0.97 μg/m3) increase in PM2.5 was associated with a 0.33 y increase in EEAA (CI = 0.01, 0.64; P = 0.04). BC and NOx (indicators or traffic exposure) were associated with DNAmAA and IEAA in women, while TeloAA was inversely associated with BC in men. We replicated this inverse BC-TeloAA association in the Normative Aging Study, a male cohort based in the USA. A multiple phenotype analysis in KORA F4 combining all aging measures showed that BC and PM10 were broadly associated with biological aging in men. Thus, we conclude that long-term exposure to air pollution is associated with biological aging measures, potentially in a sex-specific manner. However, many of the associations were relatively weak and further replication of overall and sex-specific associations is warranted. PMID:27793020

  16. Biological treatment of distillery waste for pollution-remediation.

    PubMed

    Fitzgibbon, F J; Nigam, P; Singh, D; Marchant, R

    1995-01-01

    The biological treatment of spent wash from molasses distilleries was investigated. Analysis of raw spent wash showed it to be a recalcitrant waste, with a high COD of 85,170 mg/l and containing inhibitory phenolic compounds. Reverse phase thin layer chromatography identified gallic and vanillic acid present in spent wash. The fungi Geotrichum candidum, Coriolus versicolor, Phanerochaete chrysosporium and Mycelia sterilia were screened for their ability to decolourize spent wash and to reduce the COD level. A 10 day pretreatment with Geotrichum candidum at 30 degrees C resulted in reducing the COD by 53.17% and total phenols by 47.82%, enabling other bioremediating organisms to grow. Coriolus versicolor immobilized in a packed-bed reactor reduced the COD of spent wash by a further 50.3%, giving an overall reduction in COD of 77% to 15,780 mg/l. A small amount of decolourization was achieved (4.2%), although the spent wash was still coloured. Present studies are encouraging and indicate that it is possible to bioremediate spent wash using a multi-stage treatment process involving an initial pretreatment step with Geotrichum candidum.

  17. Photocatalytic degradation of wastewater pollutants: titanium dioxide mediated degradation of methyl orange and beta-naphthol orange.

    PubMed

    Antharjanam, Sudhadevi; Philip, Robert; Suresh, Das

    2003-01-01

    The photocatalytic degradation of azo dyes such as methyl orange and beta-naphthol orange in aqueous suspensions of TiO2 has been investigated under a variety of conditions. The kinetics of degradation was studied under different conditions such as reaction pH, substrate and catalyst concentration, and types of titanium dioxide used and in the presence of electron acceptors and electron donors. The degradation rates of the dyes have been found to be strongly influenced by all the above parameters. Carbon dioxide yield measurements indicate that only partial mineralization occurs in the initial phase of oxidation.

  18. Adaptation of microbial communities from an uncontaminated aquifer to degrade organic pollutants

    SciTech Connect

    Aelion, C.M.

    1988-01-01

    This study examined the ability of the microbial community from an uncontaminated aquifer to degrade and adapt to a variety of organic pollutants. Adaptation was defined functionally as an increase in the rate of mineralization of {sup 14}C-radiolabeled substrates with exposure to the chemical. Several patterns of microbial response to xenobiotic compounds were exhibited. For some compounds, such as chlorobenzene, 1,2,4-trichlorobenzene and toluene, limited mineralization was detected during greater than 8 months of incubation. Intermediate rates of biodegradation, and a linear increase in the percentage of substrate mineralized with time were observed for m-cresol, m-aminophenol and aniline. A maximum of 10 to 15% of the label added was respired during the 3 to 5 months incubation. Phenol, ethylene dibromide and p-chlorophenol were rapidly mineralized, to a maximum of 20 to 35% of the label added within the first few weeks of incubation. Of all the compounds examined, only p-nitrophenol and m-nitrophenol elicited an adaptation response in the microbial community.

  19. Degradative Enzymes from the Pharmacy or Health Food Store: Interesting Examples for Introductory Biology Laboratories

    ERIC Educational Resources Information Center

    Deutch, Charles E.

    2007-01-01

    Degradative enzymes in over-the-counter products from pharmacies and health food stores provide good examples of biological catalysis. These include [beta]-galactosidase in Lactaid[TM], [alpha]-galactosidase in Beano[R], [alpha]-amylase and proteases in digestive aids, and proteases in contact lens cleaners. These enzymes can be studied…

  20. Pollution

    ERIC Educational Resources Information Center

    Rowbotham, N.

    1973-01-01

    Presents the material given in one class period in a course on Environmental Studies at Chesterfield School, England. The topics covered include air pollution, water pollution, fertilizers, and insecticides. (JR)

  1. [Effects of Oil Pollutants on the Performance of Marine Benthonic Microbial Fuel Cells and Its Acceleration of Degradation].

    PubMed

    Meng, Yao; Fu, Yu-bin; Liang, Sheng-kang; Chen, Wei; Liu, Zhao-hui

    2015-08-01

    Degradation of oil pollutants under the sea is slow for its oxygen-free environment which has caused long-term harm to ocean environment. This paper attempts to accelerate the degradation of the sea oil pollutants through electro catalysis by using the principle of marine benthonic microbial fuel cells (BMFCs). The influence of oil pollutants on the battery performance is innovatively explored by comparing the marine benthonic microbial fuel cells ( BMFCs-A) containing oil and oil-free microbial fuel cells (BMFCs-B). The acceleration effect of BMFCs is investigated by the comparison between the oil-degrading rate and the number of heterotrophic bacteria of the BMFCs-A and BMFCs-B on their anodes. The results show that the exchange current densities in the anode of the BMFCs-A and BMFCs-B are 1. 37 x 10(-2) A x m(-2) and 1.50 x 10(-3) A x m(-2) respectively and the maximum output power densities are 105.79 mW x m(-2) and 83.60 mW x m(-2) respectively. The exchange current densities have increased 9 times and the maximum output power density increased 1. 27 times. The anti-polarization ability of BMFCs-A is improved. The heterotrophic bacteria numbers of BMFCs-A and BMFCs-C on their anodes are (66 +/- 3.61) x 10(7) CFU x g(-1) and (7.3 +/- 2.08) x 10(7) CFU x g(-1) respectively and the former total number has increased 8 times, which accelerates the oil-degrading rate. The degrading rate of the oil in the BMFCs-A is 18.7 times higher than that in its natural conditions. The BMFCs can improve its electrochemical performance, meanwhile, the degradation of oil pollutants can also be accelerated. A new model of the marine benthonic microbial fuel cells on its acceleration of oil degradation is proposed in this article.

  2. Effects of subtle pollution at different levels of biological organisation on species-rich assemblages.

    PubMed

    Rubal, Marcos; Veiga, Puri; Reis, Pedro A; Bertocci, Iacopo; Sousa-Pinto, Isabel

    2014-08-01

    We investigated effects of subtle nutrient enrichment and metal pollution on different levels of biological organization (i.e. whole assemblage, population and individual) of species-rich assemblages. We used rockpools as model system, applying a multi-factorial sampling design to test hypotheses on differences between disturbed and reference locations. Results indicated that disturbed and reference locations supported similar assemblages, as well as individual fitness-related life-traits were ineffective to discriminate between the two conditions. In contrast, assemblages responded to pollution through a reduction of the abundance of sensitive species and a proliferation of tolerant species, although these alterations were detectable only once the influence of dominant taxa was down-weighed by data transformation. Present findings suggest that, contrarily to individual level variables, assemblage structure after data transformation and patterns of distribution and abundance of differently sensitive taxa would be a powerful tool to detect effects of subtle pollution on species-rich assemblages.

  3. Biosynthesis of gold nanoparticles by Aspergillum sp. WL-Au for degradation of aromatic pollutants

    NASA Astrophysics Data System (ADS)

    Qu, Yuanyuan; Pei, Xiaofang; Shen, Wenli; Zhang, Xuwang; Wang, Jingwei; Zhang, Zhaojing; Li, Shuzhen; You, Shengnan; Ma, Fang; Zhou, Jiti

    2017-04-01

    A simple method for synthesis of gold nanoparticles (AuNPs) using Aspergillum sp. WL-Au was presented in this study. According to UV-vis spectra and transmission electron microscopy images, the shape and size of AuNPs were affected by different parameters, including buffer solution, pH, biomass and HAuCl4 concentrations. Phosphate sodium buffer was more suitable for extracellular synthesis of AuNPs, and the optimal conditions for AuNPs synthesis were pH 7.0, biomass 100 mg/mL and HAuCl4 3 mM, leading to the production of spherical and pseudo-spherical nanoparticles. The biosynthesized AuNPs possessed excellent catalytic activities for the reduction of 2-nitrophenol, 3-nitrophenol, 4-nitrophenol, o-nitroaniline and m-nitroaniline in the presence of NaBH4, and the catalytic rate constants were calculated to be 6.3×10-3 s-1, 5.5×10-3 s-1, 10.6×10-3 s-1, 8.4×10-3 s-1 and 13.8×10-3 s-1, respectively. The AuNPs were also able to catalyze the decolorization of various azo dyes (e.g. Cationic Red X-GRL, Acid Orange II and Acid scarlet GR) using NaBH4 as the reductant, and the decolorization rates reached 91.0-96.4% within 7 min. The present study should provide a potential candidate for green synthesis of AuNPs, which could serve as efficient catalysts for aromatic pollutants degradation.

  4. Graphene oxide based ultrafiltration membranes for photocatalytic degradation of organic pollutants in salty water.

    PubMed

    Pastrana-Martínez, Luisa M; Morales-Torres, Sergio; Figueiredo, José L; Faria, Joaquim L; Silva, Adrián M T

    2015-06-15

    Flat sheet ultrafiltration (UF) membranes with photocatalytic properties were prepared with lab-made TiO2 and graphene oxide-TiO2 (GOT), and also with a reference TiO2 photocatalyst from Evonik (P25). These membranes were tested in continuous operation mode for the degradation and mineralization of a pharmaceutical compound, diphenhydramine (DP), and an organic dye, methyl orange (MO), under both near-UV/Vis and visible light irradiation. The effect of NaCl was investigated considering simulated brackish water (NaCl 0.5 g L(-1)) and simulated seawater (NaCl 35 g L(-1)). The results indicated that the membranes prepared with the GOT composite (M-GOT) exhibited the highest photocatalytic activity, outperforming those prepared with bare TiO2 (M-TiO2) and P25 (M-P25), both inactive under visible light illumination. The best performance of M-GOT may be due to the lower band-gap energy (2.9 eV) of GOT. In general, the permeate flux was also higher for M-GOT probably due to a combined effect of its highest photocatalytic activity, highest hydrophilicity (contact angles of 11°, 17° and 18° for M-GOT, M-TiO2 and M-P25, respectively) and higher porosity (71%). The presence of NaCl had a detrimental effect on the efficiency of the membranes, since chloride anions can act as hole and hydroxyl radical scavengers, but it did not affect the catalytic stability of these membranes. A hierarchically ordered membrane was also prepared by intercalating a freestanding GO membrane in the structure of the M-GOT membrane (M-GO/GOT). The results showed considerably higher pollutant removal in darkness and good photocatalytic activity under near-UV/Vis and visible light irradiation in continuous mode experiments.

  5. Systems biology defines the biological significance of redox-active proteins during cellulose degradation in an aerobic bacterium.

    PubMed

    Gardner, Jeffrey G; Crouch, Lucy; Labourel, Aurore; Forsberg, Zarah; Bukhman, Yury V; Vaaje-Kolstad, Gustav; Gilbert, Harry J; Keating, David H

    2014-10-08

    Microbial depolymerization of plant cell walls contributes to global carbon balance and is a critical component of renewable energy. The genomes of lignocellulose degrading microorganisms encode diverse classes of carbohydrate modifying enzymes, although currently there is a paucity of knowledge on the role of these proteins in vivo. We report the comprehensive analysis of the cellulose degradation system in the saprophytic bacterium Cellvibrio japonicus. Gene expression profiling of C. japonicus demonstrated that three of the 12 predicted β-1,4 endoglucanases (cel5A, cel5B, and cel45A) and the sole predicted cellobiohydrolase (cel6A) showed elevated expression during growth on cellulose. Targeted gene disruptions of all 13 predicted cellulase genes showed that only cel5B and cel6A were required for optimal growth on cellulose. Our analysis also identified three additional genes required for cellulose degradation: lpmo10B encodes a lytic polysaccharide monooxygenase (LPMO), while cbp2D and cbp2E encode proteins containing carbohydrate binding modules and predicted cytochrome domains for electron transfer. CjLPMO10B oxidized cellulose and Cbp2D demonstrated spectral properties consistent with redox function. Collectively, this report provides insight into the biological role of LPMOs and redox proteins in cellulose utilization and suggests that C. japonicus utilizes a combination of hydrolytic and oxidative cleavage mechanisms to degrade cellulose.

  6. Photocatalytic degradation of chlorophenols in soil washing wastes containing Brij 35. Correlation between the degradation kinetics and the pollutants-micelle binding.

    PubMed

    Davezza, M; Fabbri, D; Pramauro, E; Prevot, A Bianco

    2013-05-01

    The photocatalytic degradations of 4-chlorophenol (CP), 4-chloro-2-methylphenol (CMP), 4-chloro-3,5-dimethylphenol (CDMP) and 4-chloro-2-isopropyl-5-methylphenol (CIMP) were investigated in water and in simulated soil washing wastes containing Brij 35 (polyoxyethylene(23)dodecyl ether) in the presence of TiO2 dispersions. A neat inhibition of substrate decomposition proportional to their growing hydrophobicity was observed in the washing wastes for CP, CMP and CDMP, whereas CIMP showed a different behaviour. The mineralization of the organic chlorine of CP and CIMP was relatively fast and complete, whereas it was much slower for CMP and CDMP. Micellar solubilization and substrate adsorption onto the semiconductor play opposite roles on the degradation kinetics, and a breakpoint between the corresponding induced effects was evidenced when the pollutants become completely bound to the micellar aggregates.

  7. A review of Central European methods for the biological estimation of water pollution levels*

    PubMed Central

    Bick, Hartmut

    1963-01-01

    With the increasing amount and variety of pollution of surface and other waters in the modern world, there is an increasing need for simple, rapid and reliable methods for assessing the degree of purity or contamination of water. Partly for historical reasons, chemical methods have been used more widely than biological ones, although the latter possess certain advantages not shared by the former. Much important work on the biological assessment of water pollution has been done in Central Europe, and the author of this paper reviews the more significant of the modern methods evolved there. Some are ecological, some physiological; and certain of them merit consideration as standardizable procedures, applicable over a wider range of waters than those for which they were developed. To this end it will be necessary to conduct carefully controlled field trials under varying climatic and other conditions. PMID:14058231

  8. Review on fate and mechanism of removal of pharmaceutical pollutants from wastewater using biological approach.

    PubMed

    Tiwari, Bhagyashree; Sellamuthu, Balasubramanian; Ouarda, Yassine; Drogui, Patrick; Tyagi, Rajeshwar D; Buelna, Gerardo

    2017-01-01

    Due to research advancement and discoveries in the field of medical science, maintains and provides better human health and safer life, which lead to high demand for production of pharmaceutical compounds with a concomitant increase in population. These pharmaceutical (biologically active) compounds were not fully metabolized by the body and excreted out in wastewater. This micro-pollutant remains unchanged during wastewater treatment plant operation and enters into the receiving environment via the discharge of treated water. Persistence of pharmaceutical compounds in both surface and ground waters becomes a major concern due to their potential eco-toxicity. Pharmaceuticals (emerging micro-pollutants) deteriorate the water quality and impart a toxic effect on living organisms. Therefore, from last two decades, plenty of studies were conducted on the occurrence, impact, and removal of pharmaceutical residues from the environment. This review provides an overview on the fate and removal of pharmaceutical compounds via biological treatment process.

  9. Root exudates modify bacterial diversity of phenanthrene degraders in PAH-polluted soil but not phenanthrene degradation rates.

    PubMed

    Cébron, Aurélie; Louvel, Brice; Faure, Pierre; France-Lanord, Christian; Chen, Yin; Murrell, J Colin; Leyval, Corinne

    2011-03-01

    To determine whether the diversity of phenanthrene-degrading bacteria in an aged polycyclic aromatic hydrocarbon (PAH) contaminated soil is affected by the addition of plant root exudates, DNA stable isotope probing (SIP) was used. Microcosms of soil with and without addition of ryegrass exudates and with ¹³C-labelled phenanthrene (PHE) were monitored over 12 days. PHE degradation was slightly delayed in the presence of added exudate after 4 days of incubation. After 12 days, 68% of added PHE disappeared both with and without exudate. Carbon balance using isotopic analyses indicated that a part of the ¹³C-PHE was not totally mineralized as ¹³CO₂ but unidentified ¹³C-compounds (i.e. ¹³C-PHE or ¹³C-labelled metabolites) were trapped into the soil matrix. Temporal thermal gradient gel electrophoresis (TTGE) analyses of 16S rRNA genes were performed on recovered ¹³C-enriched DNA fractions. 16S rRNA gene banding showed the impact of root exudates on diversity of PHE-degrading bacteria. With PHE as a fresh sole carbon source, Pseudoxanthomonas sp. and Microbacterium sp. were the major PHE degraders, while in the presence of exudates, Pseudomonas sp. and Arthrobacter sp. were favoured. These two different PHE-degrading bacterial populations were also distinguished through detection of PAH-ring hydroxylating dioxygenase (PAH-RHD(α)) genes by real-time PCR. Root exudates favoured the development of a higher diversity of bacteria and increased the abundance of bacteria containing known PAH-RHD(α) genes.

  10. Degradation of biological weapons agents in the environment: implications for terrorism response.

    PubMed

    Stuart, Amy L; Wilkening, Dean A

    2005-04-15

    We investigate the impact on effective terrorism response of the viability degradation of biological weapons agents in the environment. We briefly review the scientific understanding and modeling of agent environmental viability degradation. In general, agent susceptibility to viability loss is greatest for vegetative bacteria, intermediate for viruses, and least for bacterial spores. Survival is greatest in soil and progressively decreases in the following environments: textiles, water, hard surfaces, and air. There is little detailed understanding of loss mechanisms. We analyze the time behavior and sensitivity of four mathematical models that are used to represent environmental viability degradation (the exponential, probability, and first- and second-order catastrophic decay models). The models behave similarly at short times (<30 min for our example case) but diverge to significantly different values at intermediate to long times. Hence, for a release event in which the majority of atmospheric exposure or deposition occurs oververy short times, the current response models likely provide a good representation of the hazard. For longer time phenomena, including decontamination, the current model capabilities are likely insufficient. Finally, we implement each model in a simple numerical integration of anthrax dispersion, viability degradation, and dose response. Decay models spanning the current knowledge of airborne degradation result in vastly different predicted hazard areas. This confounds attempts to determine necessary medical and decontamination measures. Hence,the current level of understanding and representation of environmental viability degradation in response models is inadequate to inform appropriate emergency response measures.

  11. Photocatalytic Performances of Ag3PO4 Polypods for Degradation of Dye Pollutant under Natural Indoor Weak Light Irradiation.

    PubMed

    Teng, Fei; Liu, Zailun; Zhang, An; Li, Min

    2015-08-18

    It is still a big challenge for Ag3PO4 to be applied in practice mainly because of its low stability resistant to photo corrosion, although it is an efficient photocatalyst. Herein, we have mainly investigated its activity and stability under indoor weak light for the degradation of dye pollutants. It is amazing that under indoor weak light irradiation, rhodamine B (RhB) can be completely degraded by Ag3PO4 polypods after 36 h, but only 18% of RhB by N-doped TiO2 after 120 h. It is found that under indoor weak light irradiation, the degradation rate (0.08099 h(-1)) of RhB over Ag3PO4 polypods are 46 times higher than that (0.00173 h(-1)) of N-doped TiO2. The high activity of Ag3PO4 polypods are mainly attributed to the three-dimensional branched nanostructure and high-energy {110} facets exposed. After three cycles, surprisingly, Ag3PO4 polypods show a high stability under indoor weak light irradiation, whereas Ag3PO4 have been decomposed into Ag under visible light irradiation with an artificial Xe light source. This natural weak light irradiation strategy could be a promising method for the other unstable photocatalysts in the degradation of environmental pollutants.

  12. Effect of nonionic surfactant on the degradation of glass-sorbed PCB congeners by integrated chemical-biological treatment

    SciTech Connect

    Aronstein, B.N.; Paterek, J.R.

    1995-05-01

    A study was conducted on the effect of a nonionic surfactant on the efficiency of the integrated chemical-biological treatment (ICBT) of polychlorinated biphenyls (PCBs) sorbed to the glass walls of the experimental vessels. The addition of surfactant associated with the chemical oxidation was proposed to overcome two limitations of biodegradation of hydrophobic compounds: adsorption to surfaces,a nd lack of solubility and thus availability to the microorganisms. Two {sup 14}C-labeled PCB congeners, 2-chlorobiphenyl and 2,2{prime},4,4{prime}-tetrachlorobiphenyl, were used as the test compounds. The integrated chemical-biological treatment consisted of sequential applications of Fenton`s reagent (5% H{sub 2}O{sub 2}, 1 mM FeSO{sub 4}) at pH 4.0 (with and without non-ionic surfactant Novel 2 1412-60) and the inoculation with a mixed culture of Pseudomonas sp., strain LB400, and Alcaligenes eutrophus, strain H850, at pH 8.0. The chemical treatment in the presence of surfactant affected the removal of the congeners bound to the glass surfaces of the experimental test systems. As indicated by high-pressure liquid chromatography analysis, these PCBs were converted to unidentified soluble products that are hypothesized to be partial oxidation products. No parent test compounds were detectable in the system after chemical treatment with or without surfactant. The addition of the mixed culture of PCB-degrading bacteria after completion of chemical treatment in the presence of surfactant resulted in the removal of approximately 45% of 2-chlorobiphenyl and 32% of 2,2{prime},4,4{prime}-tetrachlorobiphenyl in the form of {sup 14}CO{sub 2}. This compared to 29% and 23% without the addition of surfactant, respectively. The authors suggest that the combination of surfactant-induced desorption and chemical oxidation would increase the availability of hydrophobic pollutants for microbial degradation.

  13. Degradation of polystyrene and selected analogues by biological Fenton chemistry approaches: Opportunities and limitations.

    PubMed

    Krueger, Martin C; Seiwert, Bettina; Prager, Andrea; Zhang, Shangwei; Abel, Bernd; Harms, Hauke; Schlosser, Dietmar

    2017-04-01

    Conventional synthetic polymers typically are highly resistant to microbial degradation, which is beneficial for their intended purpose but highly detrimental when such polymers get lost into the environment. Polystyrene is one of the most widespread of such polymers, but knowledge about its biological degradability is scarce. In this study, we investigated the ability of the polymer-degrading brown-rot fungus Gloeophyllum trabeum to attack polystyrene via Fenton chemistry driven by the redox-cycling of quinones. Indications of superficial oxidation were observed, but the overall effects on the polymer were weak. To assess factors constraining biodegradation of polystyrene, the small water-soluble model compounds ethylbenzene and isopropylbenzene (cumene) were also subjected to biodegradation by G. trabeum. Likewise, ethylbenzene sulfonate, cumene sulfonate and the dimer 1,3-diphenylbutane sulfonate were used as model compounds for comparison with polystyrene sulfonate, which G. trabeum can substantially depolymerise. All model compounds but cumene were degraded by G. trabeum and yielded a large variety of oxidised metabolites, suggesting that both the very poor bioavailability of polystyrene and its inert basic structure play important roles constraining biodegradability via biologically driven Fenton chemistry.

  14. Ozone degradation of residual carbon in biological samples using microwave irradiation.

    PubMed

    Jiang, W; Chalk, S J; Kingston, H M

    1997-03-01

    In an attempt to produce complete oxidation of a biological matrix, bovine liver, ozone was investigated as an additional, potentially non-contaminating, oxidizing reagent after nitric acid digestion. Experiments were carried out to determine the decomposition efficiency of residual carbon species, primarily o-, m- and p-nitrobenzoic acids (NBAs), using ozone. The NBAs were degraded by purging sample digests with ozone, while heating the solutions with microwave energy at atmospheric pressure. The effects of the degradation temperature and solution pH on the ozonation of NBAs were determined. Solid phase extraction (C18) was used to extract NBAs from the acid digestate solutions prior to HPLC analysis. Reversed phase HPLC was used to determine NBA concentrations in digest solutions. After 2.5 h of purging ozone at 80 degrees C, 33.65 +/- 3.80% o-NBA degradation, 19.39 +/- 1.74% m-NBA degradation, and 26.47 +/- 3.36% p-NBA degradation were obtained.

  15. Carbon Nanotube Degradation in Macrophages: Live Nanoscale Monitoring and Understanding of Biological Pathway.

    PubMed

    Elgrabli, Dan; Dachraoui, Walid; Ménard-Moyon, Cécilia; Liu, Xiao Jie; Bégin, Dominique; Bégin-Colin, Sylvie; Bianco, Alberto; Gazeau, Florence; Alloyeau, Damien

    2015-10-27

    Despite numerous applications, the cellular-clearance mechanism of multiwalled carbon nanotubes (MWCNTs) has not been clearly established yet. Previous in vitro studies showed the ability of oxidative enzymes to induce nanotube degradation. Interestingly, these enzymes have the common capacity to produce reactive oxygen species (ROS). Here, we combined material and life science approaches for revealing an intracellular way taken by macrophages to degrade carbon nanotubes. We report the in situ monitoring of ROS-mediated MWCNT degradation by liquid-cell transmission electron microscopy. Two degradation mechanisms induced by hydroxyl radicals were extracted from these unseen dynamic nanoscale investigations: a non-site-specific thinning process of the walls and a site-specific transversal drilling process on pre-existing defects of nanotubes. Remarkably, similar ROS-induced structural injuries were observed on MWCNTs after aging into macrophages from 1 to 7 days. Beside unraveling oxidative transformations of MWCNT structure, we elucidated an important, albeit not exclusive, biological pathway for MWCNT degradation in macrophages, involving NOX2 complex activation, superoxide production, and hydroxyl radical attack, which highlights the critical role of oxidative stress in cellular processing of MWCNTs.

  16. Electricity generation and pollutant degradation using a novel biocathode coupled photoelectrochemical cell.

    PubMed

    Du, Yue; Feng, Yujie; Qu, Youpeng; Liu, Jia; Ren, Nanqi; Liu, Hong

    2014-07-01

    The photoelectrochemical cell (PEC) is a promising tool for the degradation of organic pollutants and simultaneous electricity recovery, however, current cathode catalysts suffer from high costs and short service lives. Herein, we present a novel biocathode coupled PEC (Bio-PEC) integrating the advantages of photocatalytic anode and biocathode. Electrochemical anodized TiO2 nanotube arrays fabricated on Ti substrate were used as Bio-PEC anodes. Field-emission scanning electron microscope images revealed that the well-aligned TiO2 nanotubes had inner diameters of 60-100 nm and wall-thicknesses of about 5 nm. Linear sweep voltammetry presented the pronounced photocurrent output (325 μA/cm(2)) under xenon illumination, compared with that under dark conditions. Comparing studies were carried out between the Bio-PEC and PECs with Pt/C cathodes. The results showed that the performance of Pt/C cathodes was closely related with the structure and Pt/C loading amounts of cathodes, while the Bio-PEC achieved similar methyl orange (MO) decoloration rate (0.0120 min(-1)) and maximum power density (211.32 mW/m(2)) to the brush cathode PEC with 50 mg Pt/C loading (Brush-PEC, 50 mg). The fill factors of Bio-PEC and Brush-PEC (50 mg) were 39.87% and 43.06%, respectively. The charge transfer resistance of biocathode was 13.10 Ω, larger than the brush cathode with 50 mg Pt/C (10.68 Ω), but smaller than the brush cathode with 35 mg Pt/C (18.35 Ω), indicating the comparable catalytic activity with Pt/C catalyst. The biocathode was more dependent on the nutrient diffusion, such as nitrogen and inorganic carbon, thus resulting in relatively higher diffusion resistance compared to the brush cathode with 50 mg Pt/C loading that yielded similar MO removal and power output. Considering the performance and cost of PEC system, the biocathode was a promising alternative for the Pt/C catalyst.

  17. Degradation of organic pollutants by Ag, Cu and Sn doped waste non-metallic printed circuit boards.

    PubMed

    Ramaswamy, Kadari; Radha, Velchuri; Malathi, M; Vithal, Muga; Munirathnam, Nagegownivari R

    2017-02-01

    The disposal and reuse of waste printed circuit boards have been the major global concerns. Printed circuit boards, a form of Electronic waste (hereafter e-waste), have been chemically processed, doped with Ag(+), Cu(2+) and Sn(2+), and used as visible light photocatalysts against the degradation of methylene blue and methyl violet. The elemental analyses of pristine and metal doped printed circuit board were obtained using energy dispersive X-ray fluorescence (EDXRF) spectra and inductively coupled plasma optical emission spectroscopy (ICP-OES). The morphology of parent and doped printed circuit board was obtained from scanning electron microscopy (SEM) measurements. The photocatalytic activity of parent and metal doped samples was carried out for the decomposition of organic pollutants, methylene blue and methyl violet, under visible light irradiation. Metal doped waste printed circuit boards (WPCBs) have shown higher photocatalytic activity against the degradation of methyl violet and methylene blue under visible light irradiation. Scavenger experiments were performed to identify the reactive intermediates responsible for the degradation of methylene blue and methyl violet. The reactive species responsible for the degradation of MV and MB were found to be holes and hydroxyl radicals. A possible mechanism of degradation of methylene blue and methyl violet is given. The stability and reusability of the catalysts are also investigated.

  18. Exploring the potential of fungi isolated from PAH-polluted soil as a source of xenobiotics-degrading fungi.

    PubMed

    Godoy, Patricia; Reina, Rocío; Calderón, Andrea; Wittich, Regina-Michaela; García-Romera, Inmaculada; Aranda, Elisabet

    2016-10-01

    The aim of this study was to find polycyclic aromatic hydrocarbon (PAH)-degrading fungi adapted to polluted environments for further application in bioremediation processes. In this study, a total of 23 fungal species were isolated from a historically pyrogenic PAH-polluted soil in Spain and taxonomically identified. The dominant groups in these samples were the ones associated with fungi belonging to the Ascomycota phylum and two isolates belonging to the Mucoromycotina subphylum and Basiodiomycota phylum. We tested their ability to convert the three-ring PAH anthracene in a 42-day time course and analysed their ability to secrete extracellular oxidoreductase enzymes. Among the 23 fungal species screened, 12 were able to oxidize anthracene, leading to the formation of 9,10-anthraquinone as the main metabolite, a less toxic one than the parent compound. The complete removal of anthracene was achieved by three fungal species. In the case of Scopulariopsis brevicaulis, extracellular enzyme independent degradation of the initial 100 μM anthracene occurred, whilst in the case of the ligninolytic fungus Fomes (Basidiomycota), the same result was obtained with extracellular enzyme-dependent transformation. The yield of accumulated 9,10-anthraquinone was 80 and 91 %, respectively, and Fomes sp. could slowly deplete it from the growth medium when offered alone. These results are indicative for the effectiveness of these fungi for pollutant removal. Graphical abstract ᅟ.

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

    PubMed

    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.

  20. Preparation of magnetic photocatalyst nanohybrid decorated by polyoxometalate for the degradation of a pharmaceutical pollutant under solar light.

    PubMed

    Bastami, Tahereh Rohani; Ahmadpour, Ali

    2016-05-01

    Magnetic polyoxometalate nanohybrid was prepared by the surface modification of γ-Fe2O3/SrCO3 nanoparticles with PW 12 O 40 (3 -) polyoxometalate (POM) anions. The results of Fourier transform infrared (FTIR) and energy-dispersive X-ray (EDX) confirm the presence of POM on the surface of γ-Fe2O3/SrCO3 nanoparticles. TEM results revealed the ellipsoid-like structure of nanohybrid which was 23 nm in length and 6 nm in width. The activity of the photocatalyst was investigated by the photocatalytic degradation of ibuprofen (IBP) in an aqueous solution under solar light. It was found that in comparison with the γ-Fe2O3/SrCO3, the degradation of IBP after 2-h exposure to the solar light irradiation was significantly higher for POM-γ-Fe2O3/SrCO3 nanohybrids. The degradation of IBP was enhanced by the addition of H2O2 to the air saturated solution, while the addition of NaHCO3 and isopropanol restricted the degradation process. In the presence of H2O2, the Fenton photocatalyst degradation under solar light irradiation led to relatively complete degradation of IBP. Furthermore, the photocatalytic activity and magnetization properties of this magnetic photocatalyst nanohybrid provide a promising solution for the degradation of water pollutants and photocatalyst recovery. Graphical Abstract Schematic illustration for preparation of POM-γ-Fe2O3/SrCO3 nanohybrid and photocatalytic reaction of IBP on POM-γ-Fe2O3/SrCO3 nanohybrid.

  1. Degradation of chlorinated paraben by integrated irradiation and biological treatment process.

    PubMed

    Wang, Shizong; Wang, Jianlong; Sun, Yuliang

    2017-03-15

    Chlorinated paraben, namely, methyl 3, 5-dichloro-4-hydroxybenzoate (MDHB) is the by-product of chlorination disinfection of paraben and frequently detected in the aquatic environments, which exhibited higher persistence and toxicity than paraben itself. In this paper, the combined irradiation and biological treatment process was employed to investigate the removal of MDHB from aqueous solution. The results showed that the removal efficiency of MDHB and total organic carbon (TOC) by irradiation process increased with radiation dose no matter what the initial concentration of MDHB was. The maximum removal efficiency of MDHB was 100%, 91.1%, 93%, respectively, for the initial concentration of MDHB of 1 mg/L, 5 mg/L and 10 mg/L with the radiation dose of 800 Gy. However, the maximum removal efficiency of TOC among all the experimental groups was only 15.3% obtained with the initial concentration of 1 mg/L at dose of 800 Gy. The subsequent biological treatment enhanced the mineralization of MDHB. The suitable radiation dose for the subsequent biological treatment was determined to be 600 Gy. In this case the removal efficiency of TOC increased to about 70%. Compared to the single biological treatment, the integrated irradiation and biological treatment significantly increase the degradation and mineralization of MDHB. Moreover, the dechlorination efficiency reached 77.4% during the integrated irradiation and biological treatment process. In addition, eight intermediates were identified during the combined process and the possible degradation pathway was proposed.

  2. Simultaneous degradation of a mixture of solvents in a biological trickling filter: Dichloromethane and methylmethacrylate

    SciTech Connect

    Okkerse, W.J.H.; Osinga-Kuipers, B.; Ottengraf, S.P.P. |

    1997-12-31

    An artificial waste gas containing dichloromethane (DCM), the target compound, and methylmethacrylate (MMA) was treated in a biological trickling filter (BTF). This type of waste gas is encountered in the plastic and coating industry. After an initial five months period at a constant DCM load of 80 g/(m{sup 3} {center_dot} h) MMA was added to the waste gas and its influence upon the DCM degradation was studied. Three different MMA loads were applied: 10, 20 and 30 g/(m{sup 3} {center_dot} h). The DCM elimination over the filter decreased at an increasing MMA load, but in all filters it reached a stable but lower level than before MMA addition. Clogging was observed at all three MMA concentrations applied. It has been speculated by what mechanistic effects the changes in the biofilm performance is brought about. Batch experiments with biofilm material taken from the BTF and short term BTF experiments were carried out to characterize the MMA degradation in the BTF`s. They showed that the first step in the MMA degradation is a rapid hydrolyzation into methanol and methacrylic acid (MCA). During normal operation the hydrolyzation intermediates are completely degraded in the BTF. A sudden increase in the MMA load, however, caused the accumulation of the intermediate methacrylic acid (MCA) in the liquid phase. Investigations of the MMA degradation of the liquid phase showed that the bulk of the MMA hydrolyzation occurred by biomass suspended in the liquid phase, instead of in the biofilm. This in contrast to the DCM degradation that was concentrated in the biofilm.

  3. Attributes of Successful Actions to Restore Lakes and Estuaries Degraded by Nutrient Pollution

    EPA Science Inventory

    As more success is achieved restoring lakes and estuaries from nutrient pollution, there is increased opportunity to evaluate the scientific, social, and policy factors associated with achieving restoration goals. We examined case studies where deliberate actions to reduce nutri...

  4. Attributes of Successful Actions to Restore Lakes and Estuaries Degraded by Nutrient Pollution-

    EPA Science Inventory

    As more success is achieved in restoring lakes and estuaries from the impacts of nutrient pollution, there is increased opportunity to evaluate the scientific, social, and policy factors associated with achieving restoration goals. We examined case studies where deliberate action...

  5. Degradation of 3-chloro-4-hydroxybenzoic acid in biological treated effluent by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Chu, Libing; Wang, Jianlong

    2016-02-01

    Gamma irradiation-induced degradation of a chlorinated aromatic compound, 3-chloro-4-hydroxybenzoic acid (CHBA) in biological treated effluent was studied and the results were compared with those obtained in deionized water. Gamma irradiation led to a complete decomposition of CHBA and a partial mineralization in the treated effluent. The removal of CHBA followed the pseudo first-order reaction kinetic model and the rate constant in the treated effluent was 1.7-3.5 times lower than that in deionized water. The CHBA degradation rate was higher at acidic condition than at neutral and alkaline conditions. The radiolytic yield, G-value for CHBA degradation was lower in the treated effluent, which decreased with increase in absorbed doses and increased with increase in initial concentrations of CHBA. The degradation mechanism of CHBA using gamma irradiation was proposed through the oxidation by -OH and reduction by eaq- and H- radicals. As exposed to gamma irradiation, dechlorination takes place rapidly and combines with the oxidation and cleavage of the aromatic ring, producing chloride ions, small carboxylic acids, acetaldehyde and other intermediates into the solution.

  6. An Understanding of the Photocatalytic Properties and Pollutant Degradation Mechanism of SrTiO3 Nanoparticles.

    PubMed

    da Silva, Luís F; Lopes, Osmando F; de Mendonça, Vagner R; Carvalho, Kele T G; Longo, Elson; Ribeiro, Caue; Mastelaro, Valmor R

    2016-05-01

    Strontium titanate nanoparticles have attracted much attention due to their physical and chemical properties, especially as photocatalysts under ultraviolet irradiation. In this paper, we analyze the effect of heating rate during the crystallization process of SrTiO3 nanoparticles in the degradation of organic pollutants. The relationship between structural, morphological and photocatalytic properties of the SrTiO3 nanoparticles was investigated using different techniques. Transmission electron microscopy and N2 adsorption results show that particle size and surface properties are tuned by the heating rate of the SrTiO3 crystallization process. The SrTiO3 nanoparticles showed good photoactivity for the degradation of methylene blue, rhodamine B and methyl orange dyes, driven by a nonselective process. The SrTiO3 sample with the largest particle size exhibited higher photoactivity per unit area, independent of the molecule to be degraded. The results pointed out that the photodegradation of methylene blue dye catalyzed by SrTiO3 is caused by the action of valence band holes (direct pathway), and the indirect mechanism has a negligible effect, i.e. degradation by O2 (-•) and (•) OH radicals attack.

  7. Application of vascular aquatic plants for pollution removal, energy and food production in a biological system

    NASA Technical Reports Server (NTRS)

    Wolverton, B. C.; Barlow, R. M.; Mcdonald, R. C.

    1975-01-01

    Vascular aquatic plants such as water hyacinths (Eichhornia crassipes) (Mart.) Solms and alligator weeds (Alternanthera philoxeroides) (Mart.) Griesb., when utilized in a controlled biological system (including a regular program of harvesting to achieve maximum growth and pollution removal efficiency), may represent a remarkably efficient and inexpensive filtration and disposal system for toxic materials and sewage released into waters near urban and industrial areas. The harvested and processed plant materials are sources of energy, fertilizer, animal feed, and human food. Such a system has industrial, municipal, and agricultural applications.

  8. Integrated assessment of oil pollution using biological monitoring and chemical fingerprinting.

    PubMed

    Lewis, Ceri; Guitart, Carlos; Pook, Chris; Scarlett, Alan; Readman, James W; Galloway, Tamara S

    2010-06-01

    A full assessment of the impact of oil and chemical spills at sea requires the identification of both the polluting chemicals and the biological effects they cause. Here, a combination of chemical fingerprinting of surface oils, tissue residue analysis, and biological effects measures was used to explore the relationship between spilled oil and biological impact following the grounding of the MSC Napoli container ship in Lyme Bay, England in January 2007. Initially, oil contamination remained restricted to a surface slick in the vicinity of the wreck, and there was no chemical evidence to link biological impairment of animals (the common limpet, Patella vulgata) on the shore adjacent to the oil spill. Secondary oil contamination associated with salvage activities in July 2007 was also assessed. Chemical analyses of aliphatic hydrocarbons and terpanes in shell swabs taken from limpet shells provided an unequivocal match with the fuel oil carried by the ship. Corresponding chemical analysis of limpet tissues revealed increased concentrations of polycyclic aromatic hydrocarbons (PAHs) dominated by phenanthrene and C1 to C3 phenanthrenes with smaller contributions from heavier molecular weight PAHs. Concurrent ecotoxicological tests indicated impairment of cellular viability (p < 0.001), reduced immune function (p < 0.001), and damage to DNA (Comet assay, p < 0.001) in these animals, whereas antioxidant defenses were elevated relative to un-oiled animals. These results illustrate the value of combining biological monitoring with chemical fingerprinting for the rapid identification of spilled oils and their sublethal impacts on biota in situ.

  9. Optical properties of dissolved organic matter (DOM): Effects of biological and photolytic degradation

    USGS Publications Warehouse

    Hansen, Angela; Kraus, Tamara; Pellerin, Brian; Fleck, Jacob; Downing, Bryan D.; Bergamaschi, Brian

    2016-01-01

    Advances in spectroscopic techniques have led to an increase in the use of optical properties (absorbance and fluorescence) to assess dissolved organic matter (DOM) composition and infer sources and processing. However, little information is available to assess the impact of biological and photolytic processing on the optical properties of original DOM source materials. We measured changes in commonly used optical properties and indices in DOM leached from peat soil, plants, and algae following biological and photochemical degradation to determine whether they provide unique signatures that can be linked to original DOM source. Changes in individual optical parameters varied by source material and process, with biodegradation and photodegradation often causing values to shift in opposite directions. Although values for different source materials overlapped at the end of the 111-day lab experiment, multivariate statistical analyses showed that unique optical signatures could be linked to original DOM source material even after degradation, with 17 optical properties determined by discriminant analysis to be significant (p<0.05) in distinguishing between DOM source and environmental processing. These results demonstrate that inferring the source material from optical properties is possible when parameters are evaluated in combination even after extensive biological and photochemical alteration.

  10. Integration of nanofiltration and biological degradation of textile wastewater containing azo dye.

    PubMed

    Paździor, Katarzyna; Klepacz-Smółka, Anna; Ledakowicz, Stanisław; Sójka-Ledakowicz, Jadwiga; Mrozińska, Zdzisława; Zyłła, Renata

    2009-04-01

    The anaerobic biological azo dyes reduction process was successfully applied to decolourization of the concentrates from the nanofiltration treatment of real textile effluents. The anaerobic phase was followed by aerobic oxidation aimed at the destruction of the aromatic amine released from azo dye. In the first experiment sequential batch reactor (SBR) combining both the anaerobic and aerobic phase in one unit was used. In the second one the anaerobic stage was separated from the aerobic one. The anaerobic phase fulfilled its aim (decolourization) in both systems (over 90%). In opposite, the aromatic amine was completely degraded in the aerobic reactor (two-sludge system), whereas the orthanilic acid was not degraded (during the aerobic phase) in SBR reactor. The COD reduction was also higher in the two-sludge system than in SBR.

  11. {gamma} Irradiation-induced degradation of organochlorinated pollutants in fatty esters and in Cod

    SciTech Connect

    Lepine, F.L.; Brochu, F.; Milot, S.

    1995-02-01

    The {gamma} irradiation-induced degradation of 2,2-bis(4-chlorophenyl)-1,1,1-trichloroethane (DDT), 2,2-bis(4-chlorophenyl)-1,1-dichloroethane (DDD), and 2,2-bis(4-chlorophenyl)-1,1-dichloroethylene (DDE) dissolved in methyl myristate and methyl oleate was studied. DDT and DDE produced DDD and 2,2-bis(4-chlorophenyl)chloroethylene (DDMU) respectively, in agreement with a previous study performed with aliphatic solvents. The degradation of these two former compounds was larger in methyl myristate than in methyl oleate and addition products between methyl myristate and the organochlorines were found. While DDD, DDE, and many PCB congeners in a cod sample were not measurably degraded at 15 KGy, DDT underwent 30% degradation. 9 refs., 1 fig., 2 tabs.

  12. The role of organic and inorganic indoor pollutants in museum environments in the degradation of dammar varnish.

    PubMed

    Bonaduce, Ilaria; Odlyha, Marianne; Di Girolamo, Francesca; Lopez-Aparicio, Susana; Grøntoft, Terje; Colombini, Maria Perla

    2013-01-21

    This paper investigates the effects of inorganic (NO(2) and O(3)) and volatile organic acid (acetic acid) pollutants on the degradation of dammar varnish in museum environments. Model paint varnish samples based on dammar resin were investigated by Gas Chromatography Mass Spectrometry (GC-MS), Dynamic Mechanical Analysis (DMA) and Atomic Force Microscopy (AFM). Dammar is a natural triterpenoid resin, commonly used as a paint varnish. Samples were subjected to accelerated ageing by different levels of pollutants (NO(2) and O(3) and acetic acid) over a range of relative humidities (RH) and then analysed. The results revealed that as the dose of the pollutant was increased, so did the degree of oxidation and cross-linking of the resin. Most interestingly, it was shown for the first time that exposure to acetic acid vapour resulted in the production of an oxidised and cross-linked resin, comparable to the resin obtained under exposure to NO(2) and O(3). These conclusions were supported by the analyses of model varnishes exposed for about two years in selected museum environments, where the levels of pollutants had been previously measured. Exposures were performed both within and outside the selected microclimate frames for paintings. Results showed that varnishes placed within the microclimate frames were not always better preserved than those exposed outside the frames. For some sites, the results highlighted the protective effects of the frames from outdoor generated pollutants, such as NO(2) and O(3). For other sites, the results showed that the microclimate frames acted as traps for the volatile organic acids emitted by the wooden components of the mc-frames, which damaged the varnish.

  13. Media-based effects on the hydrolytic degradation and crystallization of electrospun synthetic-biologic blends.

    PubMed

    Nelson, M Tyler; Johnson, Jed; Lannutti, John

    2014-02-01

    Tissue engineering scaffold degradation in aqueous environments is a widely recognized factor determining the fate of the associated anchorage-dependent cells. Electrospun blends of synthetic polycaprolactone (PCL) and a biological polymer, gelatin, of 25, 50, and 75 wt% were investigated for alterations in crystallinity, microstructure and morphology following widely used in vitro biological exposures. To our knowledge, the effects of these different aqueous-based biological media compositions on the degradation of these blends have never been directly compared. X-ray diffraction (XRD) analysis exposed that differences in PCL crystallinity were observed following exposures to phosphate buffered solution (PBS), Dulbecco's modified eagle medium (DMEM) cell culture media, and DI water following 7 days of exposure at 37 °C. XRD data suggested that in vitro medium exposures aid in providing chain mobility and rearrangement due to hydrolytic degradation of the gelatin phase, allowing previously constrained, poorly crystalline PCL regions to achieve more intense reflections resulting in the presence of crystalline peaks. The dry, as-spun modulus of relatively soft 100 % PCL fibers was approximately 10 % of any gelatin-containing composition. Tensile testing results indicate that hydrated gelatin containing scaffolds on average had a fivefold increase in elongation compared to as-spun scaffolds. After 24-h of aqueous exposure, the elastic modulus decreased in proportion to increasing gelatin content. After 1 day of exposure, the 75 and 100 % gelatin compositions largely ceased to display measurable values of modulus, elongation or tensile strength due to considerable hydrolytic degradation. On a relative basis, common aqueous in vitro medium exposures (deionized water, PBS, and DMEM) resulted in significantly divergent amounts of crystalline PCL, overall microstructure and fiber morphology in the blended compositions, subsequently 'shielding' scaffolds from

  14. Ethyl tert-butyl ether (ETBE)-degrading microbial communities in enrichments from polluted environments.

    PubMed

    Le Digabel, Yoann; Demanèche, Sandrine; Benoit, Yves; Fayolle-Guichard, Françoise; Vogel, Timothy M

    2014-08-30

    The ethyl tert-butyl ether (ETBE) degradation capacity and phylogenetic composition of five aerobic enrichment cultures with ETBE as the sole carbon and energy source were studied. In all cases, ETBE was entirely degraded to biomass and CO2. Clone libraries of the 16S rRNA gene were prepared from each enrichment. The analyses of the DNA sequences obtained showed different taxonomic compositions with a majority of Proteobacteria in three cases. The two other enrichments have different microbiota with an abundance of Acidobacteria in one case, whereas the microbiota in the second was more diverse (majority of Actinobacteria, Chlorobi and Gemmatimonadetes). Actinobacteria were detected in all five enrichments. Several bacterial strains were isolated from the enrichments and five were capable of degrading ETBE and/or tert-butyl alcohol (TBA), a degradation intermediate. The five included three Rhodococcus sp. (IFP 2040, IFP 2041, IFP 2043), one Betaproteobacteria (IFP 2047) belonging to the Rubrivivax/Leptothrix/Ideonella branch, and one Pseudonocardia sp. (IFP 2050). Quantification of these five strains and two other strains, Rhodococcus sp. IFP 2042 and Bradyrhizobium sp. IFP2049, which had been previously isolated from one of the enrichments was carried out on the different enrichments based on quantitative PCR with specific 16S rRNA gene primers and the results were consistent with the hypothesized role of Actinobacteria and Betaproteobacteria in the degradation of ETBE and the possible role of Bradyrhizobium strains in the degradation of TBA.

  15. Atmospheric pollution: a case study of degrading urban air quality over Punjab, India.

    PubMed

    Sehra, Parmjit Singh

    2007-01-01

    This paper presents the results of a case study of urban air quality over a densely populated city Ludhiana situated in Punjab, India, in the form of monthly and annual average concentrations of Suspended Particulate Matter (SPM), NO2 and SO2 for the periods 1988-1989, 1994-1999 and 2001-2005 which is generally found to be increasing with time and thus requires immediate corrective measures lest the situation becomes totally uncontrollable. The present situation is as bad as in other metropolitan Indian cities, although it seems to have somewhat improved as indicated by the latest 2001-2005 data in comparison with the past 1988-1989 and 1994-1999 data, but much more still needs to be done. In addition to the industrial and vehicular pollution, the agricultural pollution due to the burning of wheat and rice straws by the farmers should also be checked because it also creates tremendous pollution in the atmosphere.

  16. Remediation of water pollution caused by pharmaceutical residues based on electrochemical separation and degradation technologies: a review.

    PubMed

    Sirés, Ignasi; Brillas, Enric

    2012-04-01

    In the last years, the decontamination and disinfection of waters by means of direct or integrated electrochemical processes are being considered as a very appealing alternative due to the significant improvement of the electrode materials and the coupling with low-cost renewable energy sources. Many electrochemical technologies are currently available for the remediation of waters contaminated by refractory organic pollutants such as pharmaceutical micropollutants, whose presence in the environment has become a matter of major concern. Recent reviews have focused on the removal of pharmaceutical residues upon the application of other important methods like ozonation and advanced oxidation processes. Here, we present an overview on the electrochemical methods devised for the treatment of pharmaceutical residues from both, synthetic solutions and real pharmaceutical wastewaters. Electrochemical separation technologies such as membrane technologies, electrocoagulation and internal micro-electrolysis, which only isolate the pollutants from water, are firstly introduced. The fundamentals and experimental set-ups involved in technologies that allow the degradation of pharmaceuticals, like anodic oxidation, electro-oxidation with active chlorine, electro-Fenton, photoelectro-Fenton and photoelectrocatalysis among others, are further discussed. Progress on the promising solar photoelectro-Fenton process devised and further developed in our laboratory is especially highlighted and documented. The abatement of total organic carbon or reduction of chemical oxygen demand from contaminated waters allows the comparison between the different methods and materials. The routes for the degradation of the some pharmaceuticals are also presented.

  17. Stabilization of nanosized titanium dioxide by cyclodextrin polymers and its photocatalytic effect on the degradation of wastewater pollutants

    PubMed Central

    Agócs, Tamás Zoltán; Puskás, István; Varga, Erzsébet; Molnár, Mónika

    2016-01-01

    Advanced oxidation processes (AOPs) are considered highly competitive water treatment technologies for the removal of organic pollutants. Among AOP techniques, photocatalysis has recently been the most widely studied. Our aims were to investigate how the dispersion of nanosized titanium dioxide (nanoTiO2) applied in photodegradation-based procedures can be stabilized with cyclodextrins in order to obtain a new, more efficient photocatalyst for the purification of waters polluted by xenobiotics applying UV irradiation. During our work, on the one hand, we studied the behavior and stability of nanoTiO2 in cyclodextrin solutions. On the other hand, we used various monomer and polymer cyclodextrin derivatives, and assessed the options for nanoTiO2 stabilization in the presence of various salts and tap water on the basis of turbidity tests. The physical stability of nanoTiO2 dispersions is diminished in the presence of the salts found in tap water (and occurring also in surface waters and ground water) and they are precipitated immediately. This colloidal instability can be improved by cyclodextrin derivatives. Based on the results of our studies we have selected carboxymethyl β-cyclodextrin polymer (CMBCD-P) for stabilization of nanoTiO2 dispersions. The photocatalytic degradation of methylene blue and ibuprofen as model organic pollutants in various media (distilled water, NaCl solution and tap water) has been studied using nanoTiO2 as catalyst stabilized by CMBCD-P. CMBCD-P itself showed a catalytic effect on the UV degradation of methylene blue. In addition to enhancing the colloid stability of nanoTiO2 CMBCD-P showed also synergistic effects in catalyzing the photodecomposition process of the dye. On the other hand, ibuprofen as a model pharmaceutical, a pollutant of emerging concern (EP), was protected by CMBCD-P against the photocatalytic degradation showing that inclusion complex formation can result in opposite effects depending on the structure of the host

  18. Feasibility study of a compact process for biological treatment of highly soluble VOCs polluted gaseous effluent.

    PubMed

    Daubert, I; Lafforgue, C; Maranges, C; Fonade, C

    2001-01-01

    Volatile organic compounds (VOCs), representing a wide range of products mainly generated by industrial activity, are involved in air pollution. This study deals with a new biological treatment process of gaseous effluent combining a gas/liquid contactor called an "aero-ejector" and a membrane bioreactor. Combining these two innovative technologies enables a high elimination efficiency to be reached. We first focus on transfer phenomena characterization in a pilot installation on a laboratory scale, using a gaseous effluent polluted with a low ethanol concentration (7.1 x 10(-3) kg.m(-3)). These experiments demonstrated the good transfer performances since 90% of the ethanol was absorbed in the liquid phase in one step. After this physical characterization, the biological aspect of the system was studied using the yeast Candida utilis as microorganism. During the experiment, no ethanol was measured in the fermentation broth nor in the outlet gas, confirming the efficiency of ethanol elimination by C. utilis. The experimental procedure emerging from the present study strongly validates the suitability of this process for ethanol removal from air.

  19. Biological assessment to support ecological recovery of a degraded headwater system.

    PubMed

    Longing, Scott D; Haggard, Brian E

    2010-09-01

    An assessment of the benthic macroinvertebrate community was conducted to characterize the ecological recovery of a channelized main stem and two small tributaries at the Watershed Research and Education Center (WREC, Arkansas, USA). Three other headwater streams in the same basin were also sampled as controls and for biological reference information. A principal components analysis produced stream groupings along an overall gradient of physical habitat integrity, with degraded reaches showing lower RBP habitat scores, reduced flow velocities, smaller substrate sizes, greater conductivity, and higher percentages of sand and silt substrate. The benthic macroinvertebrate assemblage at WREC was dominated by fast-reproducing dipteran larvae (midge and mosquito larvae) and physid snails, which comprised 71.3% of the total macroinvertebrate abundance over three sampling periods. Several macroinvertebrate assemblage metrics should provide effective targets for monitoring overall improvements in the invertebrate assemblage including recovery towards a more complex food web (e.g., total number of taxa, number of EPT taxa, percent 2 dominant taxa). However, current habitat conditions and the extent of existing degradation, system isolation and surrounding urban or agricultural land-uses might affect the level of positive change to the system. We therefore suggest a preliminary restoration strategy involving the addition of pool habitats in the system. At one pool we collected a total of 29 taxa (dominated by water beetle predators), which was 59% of total number of taxa collected at WREC. Maintaining water-retentive pools to collect flows and maintain water permanence focuses on enhancing known biology and habitat, thus reducing the effects of abiotic filters on macroinvertebrate assemblage recovery. Furthermore, biological assessment prior to restoration supports a strategy primarily focused on improving the existing macroinvertebrate community in the current context of the

  20. Chemical and biological pollution contribute to the immunological profiles of free-ranging harbor seals.

    PubMed

    Mos, Lizzy; Morsey, Brenda; Jeffries, Steven J; Yunker, Mark B; Raverty, Stephen; De Guise, Sylvain; Ross, Peter S

    2006-12-01

    Polychlorinated biphenyls and other persistent organic pollutants have been associated with immunotoxicity and outbreaks of (infectious) disease in marine mammals by rendering them vulnerable to infection by pathogens such as viruses and bacteria. In an immunotoxicological study of free-ranging harbor seals (Phoca vitulina), we obtained samples of blood and blubber from seal pups that were live-captured from two remote and two near-urban sites in British Columbia, Canada, and Washington state, USA. Using these samples, we quantified hematology, innate immune function, adaptive immune function, and polychlorinated biphenyl accumulation. While controlling for confounding factors (age, sex, and condition), univariate correlations between phagocytosis (r2 = 0.30, p = 0.002), respiratory burst (r2 =0.45, p= 0.000), T-lymphocyte function (r2 = 0.16, p = 0.028), lymphocyte signaling (r2 = 0.17, p = 0.025), and lymphocyte counts (r2 = 0.29, p = 0.002), and polychlorinated biphenyl concentrations suggested chemical-associated immunotoxicity. Principal component analysis of immunological endpoints provided additional evidence of immunotoxic effects in seals. However, principal component analysis also identified a noncontaminant-related factor by distinguishing between seals inhabiting urban versus remote sites, with results being consistent with increased pathogen exposure. Elevated fecal coliform concentrations in water, and observations of terrestrial spill-over pathogens in local seals, further support the notion of biological pollution at these sites. Although our study highlights the role that environmental contaminants might play in rendering marine mammal populations vulnerable to disease through immunotoxicity, it also suggests that biological pollution represents an emerging conservation concern.

  1. Combined use of native and caged mussels to assess biological effects of pollution through the integrative biomarker approach.

    PubMed

    Marigómez, Ionan; Zorita, Izaskun; Izagirre, Urtzi; Ortiz-Zarragoitia, Maren; Navarro, Patricia; Etxebarria, Nestor; Orbea, Amaia; Soto, Manu; Cajaraville, Miren P

    2013-07-15

    Native and caged mussels were used in combination for the monitoring of pollution biological effects through an integrative biomarker approach. Mussels (Mytilus galloprovincialis) were deployed in cages in two well-known model localities with different pollution levels in the Basque coast. After 3 weeks caged and native mussels were collected from each site and a suite of effect and exposure biomarkers (from molecular/cellular to organism level) was applied and chemical contaminants (metals, PAHs, PCBs, phthalates and nonylphenol ethoxylates) were analytically determined. Integrative biomarker indices and pollutant indices of tissues were calculated. Several biomarkers used herein responded similarly in native and caged mussels, whereas others exhibited significant differences. Overall, biomarkers in-a-suite depicted site-specific profiles useful for the diagnostic of mussel health status and therefore for ecosystem health assessment in marine pollution biomonitoring. On the other hand, biomarkers and bioaccumulation exhibited different response times, which was especially evident when comparing biomarker and pollutant indices of tissues. The suite of biomarkers was more sensitive after caging (short-term response), whereas tissue pollutant concentrations were more sensitive in native mussels (long-term response). Thus, the combination of native and caged mussels is highly recommended to monitor biological effects of pollution in mussels through the integrative biomarker approach, especially in chronically polluted sites.

  2. A novel method developed for estimating mineralization efficiencies and its application in PC and PEC degradations of large molecule biological compounds with unknown chemical formula.

    PubMed

    Li, Guiying; Liu, Xiaolu; An, Taicheng; Wong, Po Keung; Zhao, Huijun

    2016-05-15

    A new method to estimate the photocatalytic (PC) and photoelectrocatalytic (PEC) mineralization efficiencies of large molecule biological compounds with unknown chemical formula in water was firstly developed and experimentally validated. The method employed chemical oxidation under the standard dichromate chemical oxygen demand (COD) conditions to obtain QCOD values of model compounds with unknown chemical formula. The measured QCOD values were used as the reference to replace QCOD values of model compounds for calculation of the mineralization efficiencies (in %) by assuming the obtained QCOD values are the measure of the theoretical charge required for the complete mineralization of organic pollutants. Total organic carbon (TOC) was also employed as a reference to confirm the mineralization capacity of dichromate chemical oxidation. The developed method was applied to determine the degradation extent of model compounds, such as bovine serum albumin (BSA), lecithin and bacterial DNA, by PC and PEC. Incomplete PC mineralization of all large molecule biological compounds was observed, especially for BSA. But the introduction of electrochemical technique into a PC oxidation process could profoundly improve the mineralization efficiencies of model compounds. PEC mineralization efficiencies of bacterial DNA was the highest, while that of lecithin was the lowest. Overall, PEC degradation method was found to be much effective than PC method for all large molecule biological compounds investigated, with PEC/PC mineralization ratios followed an order of BSA > lecithin > DNA.

  3. Suspended sediment in tidal currents: an often-neglected pollutant that aggravates mangrove degradation.

    PubMed

    Fu, Weiguo; Liu, Daomin; Yin, Qilin; Wu, Yanyou; Li, Pingping

    2014-07-15

    In this study, the influence of sediments deposited on the leaves of different mangrove species due to tidal movements on photosynthetic characteristics and chlorophyll fluorescence of the species was explored. The degree of accelerated degradation among different mangrove species was also obtained. Results show that the leaves of mangrove species have varying degrees of sediment deposition. Sediment deposition leads to photosynthetic reduction and physiological stress among Kandelia candel, Aegiceras corniculatum, and Avicennia marina in the Quanzhou Bay. Thus, the deposition of suspended sediments from tidal currents is an important environmental factor that accelerates the degradation of some mangrove species.

  4. Transcriptional profiling of Gram-positive Arthrobacter in the phyllosphere: induction of pollutant degradation genes by natural plant phenolic compounds.

    PubMed

    Scheublin, Tanja R; Deusch, Simon; Moreno-Forero, Silvia K; Müller, Jochen A; van der Meer, Jan Roelof; Leveau, Johan H J

    2014-07-01

    Arthrobacter chlorophenolicus A6 is a Gram-positive, 4-chlorophenol-degrading soil bacterium that was recently shown to be an effective colonizer of plant leaf surfaces. The genetic basis for this phyllosphere competency is unknown. In this paper, we describe the genome-wide expression profile of A.chlorophenolicus on leaves of common bean (Phaseolus vulgaris) compared with growth on agar surfaces. In phyllosphere-grown cells, we found elevated expression of several genes known to contribute to epiphytic fitness, for example those involved in nutrient acquisition, attachment, stress response and horizontal gene transfer. A surprising result was the leaf-induced expression of a subset of the so-called cph genes for the degradation of 4-chlorophenol. This subset encodes the conversion of the phenolic compound hydroquinone to 3-oxoadipate, and was shown to be induced not only by 4-chlorophenol but also hydroquinone, its glycosylated derivative arbutin, and phenol. Small amounts of hydroquinone, but not arbutin or phenol, were detected in leaf surface washes of P.vulgaris by gas chromatography-mass spectrometry. Our findings illustrate the utility of genomics approaches for exploration and improved understanding of a microbial habitat. Also, they highlight the potential for phyllosphere-based priming of bacteria to stimulate pollutant degradation, which holds promise for the application of phylloremediation.

  5. Marine pollution

    SciTech Connect

    Albaiges, J. )

    1989-01-01

    This book covers the following topics: Transport of marine pollutants; Transformation of pollutants in the marine environment; Biological effects of marine pollutants; Sources and transport of oil pollutants in the Persian Gulf; Trace metals and hydrocarbons in Syrian coastal waters; and Techniques for analysis of trace pollutants.

  6. Evident bacterial community changes but only slight degradation when polluted with pyrene in a red soil

    PubMed Central

    Ren, Gaidi; Ren, Wenjie; Teng, Ying; Li, Zhengao

    2015-01-01

    Understanding the potential for Polycyclic aromatic hydrocarbons (PAH) degradation by indigenous microbiota and the influence of PAHs on native microbial communities is of great importance for bioremediation and ecological evaluation. Various studies have focused on the bacterial communities in the environment where obvious PAH degradation was observed, little is known about the microbiota in the soil where poor degradation was observed. Soil microcosms were constructed with a red soil by supplementation with a high-molecular-weight PAH (pyrene) at three dosages (5, 30, and 70 mg ⋅ kg-1). Real-time PCR was used to evaluate the changes in bacterial abundance and pyrene dioxygenase gene (nidA) quantity. Illumina sequencing was used to investigate changes in diversity, structure, and composition of bacterial communities. After 42 days of incubation, no evident degradation was observed. The poor degradation ability was associated with the stability or significant decrease of abundance of the nidA gene. Although the abundance of the bacterial 16S rRNA gene was not affected by pyrene, the bacterial richness and diversity were decreased with increasing dosage of pyrene and the community structure was changed. Phylotypes affected by pyrene were comprehensively surveyed: (1) at the high taxonomic level, seven of the abundant phyla/classes (relative abundance >1.0%) including Chloroflexi, AD3, WPS-2, GAL5, Alphaproteobacteria, Actinobacteria, and Deltaproteobacteria and one rare phylum Crenarchaeota were significantly decreased by at least one dosage of pyrene, while three phyla/classes (Acidobacteria, Betaproteobacteria, and Gammaproteobacteria) were significantly increased; and (2) at the lower taxonomic level, the relative abundances of twelve orders were significantly depressed, whereas those of nine orders were significantly increased. This work enhanced our understanding of the biodegradation potential of pyrene in red soil and the effect of pyrene on soil ecosystems

  7. Attributes of successful actions to restore lakes and estuaries degraded by nutrient pollution.

    PubMed

    Gross, Catharine; Hagy, James D

    2017-02-01

    As more success is achieved in restoring lakes and estuaries from the impacts of nutrient pollution, there is increased opportunity to evaluate the scientific, social, and policy factors associated with achieving restoration goals. We examined case studies where deliberate actions to reduce nutrient pollution and restore ecosystems resulted in ecological recovery. Prospective cases were identified from scientific literature and technical documents for lakes and estuaries with: (1) scientific evidence of nutrient pollution; (2) restoration actions taken to mitigate nutrient pollution; and (3) documented ecological improvement. Using these criteria, we identified 9 estuaries and 7 lakes spanning countries, climatic regions, physical types, depths, and watershed areas. Among 16 case studies ultimately included, 8 achieved improvements short of stated restoration goals. Five more were successful initially, but condition subsequently declined. Three of the case studies achieved their goals fully and are currently managing to maintain the restored condition. We examined each case to identify both common attributes of nutrient management, grouped into 'themes', and variations on those attributes, which were coded into categorical variables based on thorough review of documents associated with each case. The themes and variables were organized into a broad conceptual model illustrating how they relate to each other and to nutrient management outcomes. We then explored relationships among the themes and variables using multiple correspondence analysis (MCA). Results of the MCA suggested that the attributes most associated with achieving restoration goals include: (1) leadership by a dedicated watershed management agency; (2) governance through a bottom-up collaborative process; (3) a strategy that set numeric targets based on a specific ecological goal; and (4) actions to reduce nutrient loads from all sources. While our study did not provide a comprehensive road map to

  8. Coal mining activities change plant community structure due to air pollution and soil degradation.

    PubMed

    Pandey, Bhanu; Agrawal, Madhoolika; Singh, Siddharth

    2014-10-01

    The aim of this study was to investigate the effects of coal mining activities on the community structures of woody and herbaceous plants. The response of individual plants of community to defilement caused by coal mining was also assessed. Air monitoring, soil physico-chemical and phytosociological analyses were carried around Jharia coalfield (JCF) and Raniganj coalfield. The importance value index of sensitive species minified and those of tolerant species enhanced with increasing pollution load and altered soil quality around coal mining areas. Although the species richness of woody and herbaceous plants decreased with higher pollution load, a large number of species acclimatized to the stress caused by the coal mining activities. Woody plant community at JCF was more affected by coal mining than herbaceous community. Canonical correspondence analysis revealed that structure of herbaceous community was mainly driven by soil total organic carbon, soil nitrogen, whereas woody layer community was influenced by sulphur dioxide in ambient air, soil sulphate and soil phosphorus. The changes in species diversity observed at mining areas indicated an increase in the proportion of resistant herbs and grasses showing a tendency towards a definite selection strategy of ecosystem in response to air pollution and altered soil characteristics.

  9. INFLUENCE OF ENVIRONMENTAL CHANGES ON DEGRADATION OF CHIRAL POLLUTANTS IN SOILS

    EPA Science Inventory

    Numerous anthropogenic chemicals of environmental concern- including some phenoxy acid herbicides, organophosphorus insecticides, polychlorinated biphenyls, phthalates, freon substi- tutes and some DDT derivatives- are chiral. Their potential biological effects, such as toxicity,...

  10. Design of a Metal Oxide-Organic Framework (MoOF) Foam Microreactor: Solar-Induced Direct Pollutant Degradation and Hydrogen Generation.

    PubMed

    Zhu, Liangliang; Fu Tan, Chuan; Gao, Minmin; Ho, Ghim Wei

    2015-12-16

    A macroporous carbon network combined with mesoporous catalyst immobilization by a template method gives a metal-oxide-organic framework (MoOF) foam microreactor that readily soaks up pollutants and localizes solar energy in itself, leading to effective degradation of water pollutants (e.g., methyl orange (MO) and also hydrogen generation. The cleaned-up water can be removed from the microreactor simply by compression, and the microreactor used repeatedly.

  11. Influence of supporting electrolyte in electricity generation and degradation of organic pollutants in photocatalytic fuel cell.

    PubMed

    Khalik, Wan Fadhilah; Ong, Soon-An; Ho, Li-Ngee; Wong, Yee-Shian; Voon, Chun-Hong; Yusuf, Sara Yasina; Yusoff, Nik Athirah; Lee, Sin-Li

    2016-08-01

    This study investigated the effect of different supporting electrolyte (Na2SO4, MgSO4, NaCl) in degradation of Reactive Black 5 (RB5) and generation of electricity. Zinc oxide (ZnO) was immobilized onto carbon felt acted as photoanode, while Pt-coated carbon paper as photocathode was placed in a single chamber photocatalytic fuel cell, which then irradiated by UV lamp for 24 h. The degradation and mineralization of RB5 with 0.1 M NaCl rapidly decreased after 24-h irradiation time, followed by MgSO4, Na2SO4 and without electrolyte. The voltage outputs for Na2SO4, MgSO4 and NaCl were 908, 628 and 523 mV, respectively, after 24-h irradiation time; meanwhile, their short-circuit current density, J SC, was 1.3, 1.2 and 1.05 mA cm(-2), respectively. The power densities for Na2SO4, MgSO4 and NaCl were 0.335, 0.256 and 0.245 mW cm(-2), respectively. On the other hand, for without supporting electrolyte, the voltage output and short-circuit current density was 271.6 mV and 0.055 mA cm(-2), respectively. The supporting electrolyte NaCl showed greater performance in degradation of RB5 and generation of electricity due to the formation of superoxide radical anions which enhance the degradation of dye. The mineralization of RB5 with different supporting electrolyte was measured through spectrum analysis and reduction in COD concentration.

  12. Reduction of pollutants in pulp paper mill effluent treated by PCP-degrading bacterial strains.

    PubMed

    Chandra, Ram; Raj, Abhay; Yadav, Sangeeta; Patel, Devendra Kumar

    2009-08-01

    Two PCP-degrading bacterial strains, Bacillus cereus (ITRC-S6) and Serratia marcescens (ITRC-S7) were used for the treatment of pulp and paper mill effluent at conditions; 1.0% glucose and 0.5% peptone at 30 +/- 1 degrees C at 120 rpm for 168 h of incubation. These two bacterial strains effectively reduced colour (45-52%), lignin (30-42%), BOD (40-70%), COD (50-60%), total phenol (32-40%) and PCP (85-90%) within 168 h of incubation. However, the highest reduction in colour (62%), lignin (54%), BOD (70%), COD (90%), total phenol (90%) and PCP (100%) was recorded by mixed culture treatment. The bacterial mechanism for the degradation of pulp and paper mill effluent may be explained by an increase in the cells biomass using added co-substrates resulting liberation of significant amount of chloride due to bacterial dechlorination of chlorolignins and chlorophenols this showed reduction in colour, lignin and toxicity in the effluent. Further, GC-MS analysis of ethyl acetate-extractable compounds from treated pulp paper mill effluent reinforces the bacterium capability for the degradation of lignin and pentachlorophenol, as many aromatic compounds such as 2-chlorophenol, 2, 4, 6-trichlorophenol and tetrachlorohydroquinone, 6-chlorohydroxyquinol and tetrachlorohydroquinone detected which were not present in the untreated effluent.

  13. Analysis of organic pollutant degradation in pulsed plasma by coherent anti-Stokes Raman spectroscopy

    SciTech Connect

    Bratescu, Maria Antoneta; Hieda, Junko; Umemura, Tomonari; Saito, Nagahiro; Takai, Osamu

    2011-05-15

    The degradation of p-benzoquinone (p-BQ) in water was investigated by the coherent anti-Stokes Raman spectroscopy (CARS) method, in which the change of the anti-Stokes signal intensity corresponding to the vibrational transitions of the molecule is monitored during and after solution plasma processing (SPP). In the beginning of SPP treatment, the CARS signal intensity of the ring vibrational molecular transitions at 1233 and 1660 cm{sup -1} increases under the influence of the electric field of the plasma, depending on the delay time between the plasma pulse and the laser firing pulse. At the same time, the plasma contributes to the degradation of p-BQ molecules by generating hydrogen and hydroxyl radicals, which decompose p-BQ into different carboxylic acids. After SPP, the CARS signal intensity of the vibrational bands of p-BQ ceased and the degradation of p-BQ was confirmed by UV-visible absorption spectroscopy and liquid chromatography analysis.

  14. From pollutant gas to biological messenger: the diverse actions of nitric oxide in cancer.

    PubMed Central

    Brennan, Peter A.; Moncada, Salvador

    2002-01-01

    Nitric oxide (NO) has undergone an image change in recent years. Previously regarded as a toxic pollutant gas, it has now become the subject of intense research in many fields of medicine and science. It is a free radical, with a diverse range of actions in both physiological and pathological processes. Although over 44,000 research papers have now been written on NO, only a small number have originated from the surgical specialties. Its role in tumour biology remains incompletely understood. NO is known to have both tumour promoting and inhibitory effects, presumed to be dependent on its local concentration within the tumour. NO appears to be pivotal in the angiogenic process, and the p53 tumour suppressor gene may influence its production. This review summarises the brief history of this molecule, gives an overview of its many effects in the common solid tumours and discusses how targeting of NO production may have possible future therapeutic benefit. PMID:11995767

  15. Degradation of organic pollutants and microorganisms from wastewater using different dielectric barrier discharge configurations--a critical review.

    PubMed

    Mouele, Emile S Massima; Tijani, Jimoh O; Fatoba, Ojo O; Petrik, Leslie F

    2015-12-01

    The growing global drinking water crisis requires the development of novel advanced, sustainable, and cost-effective water treatment technologies to supplement the existing conventional methods. One such technology is advanced oxidation based on dielectric barrier discharge (DBD). DBD such as single and double planar and single and double cylindrical dielectric barrier configurations have been utilized for efficient degradation of recalcitrant organic pollutants. The overall performance of the different DBD system varies and depends on several factors. Therefore, this review was compiled to give an overview of different DBD configurations vis-a-viz their applications and the in situ mechanism of generation of free reactive species for water and wastewater treatment. Our survey of the literature indicated that application of double cylindrical dielectric barrier configuration represents an ideal and viable route for achieving greater water and wastewater purification efficiency.

  16. 2D Transition Metal Dichalcogenides and Graphene-Based Ternary Composites for Photocatalytic Hydrogen Evolution and Pollutants Degradation

    PubMed Central

    Chen, Ying; Sun, Hongqi; Peng, Wenchao

    2017-01-01

    Photocatalysis have attracted great attention due to their useful applications for sustainable hydrogen evolution and pollutants degradation. Transition metal dichalcogenides (TMDs) such as MoS2 and WS2 have exhibited great potential as cocatalysts to increase the photo-activity of some semiconductors. By combination with graphene (GR), enhanced cocatalysts of TMD/GR hybrids could be synthesized. GR here can act as a conductive electron channel for the transport of the photogenerated electrons, while the TMDs nanosheets in the hybrids can collect electrons and act as active sites for photocatalytic reactions. This mini review will focus on the application of TMD/GR hybrids as cocatalysts for semiconductors in photocatalytic reactions, by which we hope to provide enriched information of TMD/GR as a platform to develop more efficient photocatalysts for solar energy utilization. PMID:28336898

  17. Fabrication of Ag/TiO2 nanotube array with enhanced photo-catalytic degradation of aqueous organic pollutant

    NASA Astrophysics Data System (ADS)

    Ma, Jie; Yang, Mingxuan; Sun, Yiran; Li, Chenlu; Li, Qiang; Gao, Fangfang; Yu, Fei; Chen, Junhong

    2014-04-01

    In this paper, the fabrication of Ag/TiO2 nanotube arrays and their photo-catalytic activity have been studied. The SEM, TEM and XRD were performed to characterize the morphology and crystalline phase of the TiO2 nanotube array and Ag/TiO2 nanotube array. Ag nanoparticles with different loadings, which are aimed to suppress the electron-hole recombination so as to enhance the photo-catalytic oxidation efficiency, were systematically coated onto TiO2 nanotubes. The photo-catalytic activity of these nano-materials was evaluated by the degradation of two different pollutants: methyl orange and glyphosate. The effects of various parameters, such as the amount of the photo-catalyst, the illumination time, and pH value on the photo-catalytic oxidation activity, were studied.

  18. Fundamental understanding of the thermal degradation mechanisms of waste tires and their air pollutant generation in a N2 atmosphere.

    PubMed

    Kwon, Eilhann; Castaldi, Marco J

    2009-08-01

    The thermal decomposition of waste tires has been characterized via thermo-gravimetric analysis (TGA) tests, and significant mass loss has been observed between 300 and 500 degrees C. A series of gas chromatography-mass spectrometer (GC-MS) measurements, in which the instrument was coupled to a TGA unit, have been carried out to investigate the thermal degradation mechanisms as well as the air pollutant generation including volatile organic carbons (VOCs) and polycyclic aromatic hydrocarbons (PAHs) in a nitrogen atmosphere. In order to understand fundamental information on the thermal degradation mechanisms of waste tires, the main constituents of tires, poly-isoprene rubber (IR) and styrene butadiene rubber (SBR), have been studied under the same conditions. All of the experimental work indicated that the bond scission on each monomer of the main constituents of tires was followed by hydrogenation and gas phase reactions. This helped to clarify the independent pathways and species attributable to IR and SBR during the pyrolysis process. To extend that understanding to a more practical level, a flow-through reactor was used to test waste tire, SBR and IR samples in the temperature range of 500-800 degrees C at a heating rate of approximately 200 degrees C. Lastly, the formation of VOCs (approximately 1-50 PPMV/10 mg of sample) and PAHs (approximately 0.2-7 PPMV/10 mg of sample) was observed at relatively low temperatures compared to conventional fuels, and its quantified concentration was significantly high due to the chemical structure of SBR and IR. The measurement of chemicals released during pyrolysis suggests not only a methodology for reducing the air pollutants but also the feasibility of petrochemical recovery during thermal treatment.

  19. Coupling membrane separation and photocatalytic oxidation processes for the degradation of pharmaceutical pollutants.

    PubMed

    Martínez, F; López-Muñoz, M J; Aguado, J; Melero, J A; Arsuaga, J; Sotto, A; Molina, R; Segura, Y; Pariente, M I; Revilla, A; Cerro, L; Carenas, G

    2013-10-01

    The coupling of membrane separation and photocatalytic oxidation has been studied for the removal of pharmaceutical pollutants. The retention properties of two different membranes (nanofiltration and reverse osmosis) were assessed. Comparable selectivity on the separation of pharmaceuticals were observed for both membranes, obtaining a permeate stream with concentrations of each pharmaceutical below 0.5 mg L(-)(1) and a rejected flux highly concentrated (in the range of 16-25 mg L(-)(1) and 18-32 mg L(-)(1) of each pharmaceutical for NF-90 and BW-30 membranes, respectively), when an initial stream of six pharmaceuticals was feeding to the membrane system (10 mg L(-)(1) of each pharmaceutical). The abatement of concentrated pharmaceuticals of the rejected stream was evaluated by means of heterogeneous photocatalytic oxidation using TiO2 and Fe2O3/SBA-15 in presence of hydrogen peroxide as photo-Fenton system. Both photocatalytic treatments showed remarkable removals of pharmaceutical compounds, achieving values between 80 and 100%. The nicotine was the most refractory pollutant of all the studied pharmaceuticals. Photo-Fenton treatment seems to be more effective than TiO2 photocatalysis, as high mineralization degree and increased nicotine removal were attested. This work can be considered an interesting approach of coupling membrane separation and heterogeneous photocatalytic technologies for the successful abatement of pharmaceutical compounds in effluents of wastewater treatment plants.

  20. Plant volatiles in a polluted atmosphere: stress response and signal degradation

    PubMed Central

    Blande, James D.; Holopainen, Jarmo K.; Niinemets, Ülo

    2014-01-01

    Plants emit a plethora of volatile organic compounds, which provide detailed information on the physiological condition of emitters. Volatiles induced by herbivore-feeding are among the best studied plant responses to stress and may constitute an informative message to the surrounding community and function in the process of plant defence. However, under natural conditions, plants are potentially exposed to multiple concurrent stresses, which can have complex effects on the volatile emissions. Atmospheric pollutants are an important facet of the abiotic environment and can impinge on a plant’s volatile-mediated defences in multiple ways at multiple temporal scales. They can exert changes in volatile emissions through oxidative stress, as is the case with ozone pollution. They may also react with volatiles in the atmosphere; such is the case for ozone, nitrogen oxides, hydroxyl radicals and other oxidizing atmospheric species. These reactions result in breakdown products, which may themselves be perceived by community members as informative signals. In this review we demonstrate the complex interplay between stress, emitted signals and modification in signal strength and composition by the atmosphere, collectively determining the responses of the biotic community to elicited signals. PMID:24738697

  1. Characterization of Radiation Fields in Biological Shields of Nuclear Power Plants for Assessing Concrete Degradation

    SciTech Connect

    Remec, Igor; Rosseel, Thomas M; Field, Kevin G; Pape, Yann Le

    2016-01-01

    Life extensions of nuclear power plants to 60 and potentially 80 years of operation have renewed interest in long-term material degradation. One material being considered is concrete with a particular focus on radiation-induced effects. Based on the projected neutron fluence (E > 0.1 MeV) values in the concrete biological shields of the US PWR fleet and the available data on radiation effects on concrete, some decrease in mechanical properties of concrete cannot be ruled out during extended operation beyond 60 years. An expansion of the irradiated concrete database and a reliable determination of relevant neutron fluence energy cutoff value are necessary to assure reliable risk assessment for NPPs extended operation.

  2. The use of the fungus Dichomitus squalens for degradation in rotating biological contactor conditions.

    PubMed

    Novotný, Ceněk; Trošt, Nina; Šlušla, Martin; Svobodová, Kateřina; Mikesková, Hana; Válková, Hana; Malachová, Kateřina; Pavko, Aleksander

    2012-06-01

    Biodegradation potential of Dichomitus squalens in biofilm cultures and rotating biological contactor (RBC) was investigated. The fungus formed thick biofilms on inert and lignocellulosic supports and exhibited stable activities of laccase and manganese peroxidase to reach 40-62 and 25-32% decolorization of anthraquinone Remazol Brilliant Blue R and heterocyclic phthalocyanine dyes, respectively. The decolorization ceased when glucose concentration dropped to 1 mmol l(-1). In RBC reactor, respective decolorizations of Remazol Brilliant Blue R and heterocyclic Methylene Blue and Azure B dyes (50 mg l(-1)) attained 99%, 93%, and 59% within 7, 40 and 200 h. The fungus exhibited tolerance to coliform and non-coliform bacteria on rich organic media, the inhibition occurred only on media containing tryptone and NaCl. The degradation efficiency in RBC reactor, capability to decolorize a wide range of dye structures and tolerance to bacterial stress make D. squalens an organism applicable to remediation of textile wastewaters.

  3. Biological degradation of catechol in wastewater using the sequencing continuous-inflow reactor (SCR).

    PubMed

    Aghapour, Ali Ahmad; Moussavi, Gholamreza; Yaghmaeian, Kamyar

    2013-05-24

    Catechol is used in many industries. It can be removed from wastewater by various methods but biological processes are the most superior and commonly used technology. The SCR is a modified form of SBR used to degrade catechol. The objective of this study was to investigate the performance of SCR for biodegradation and mineralization of catechol under various inlet concentrations (630-1500 mg/L) and hydraulic retention times (HRT) (18-9 h). This study used a bench scale SCR setup to test catechol degradation. The acclimation time of biomass for catechol at degradation at 630 mg/L was 41 d. The SCR operating cycle time was 6 h and the consecutive times taken for aerating, settling and decanting were 4, 1.5 and 0.5 h, respectively. This study investigated the effects of inlet catechol concentration (630-1560 mg/L) and HRT (18-9 h). The average catechol removal efficiencies in steady-state conditions of 630, 930, 12954 and 1559 mg/L of catechol were 98.5%, 98.5%, 98.2% and 96.9% in terms catechol and 97.8%, 97.7%, 96.4% and 94.3% for COD, respectively. SCR with acclimated biomasses could effectively remove the catechol and the corresponding COD from wastewater with concentrations of up to 1560, at the loading rate of 5.38 kg COD/m3.d and at a HRT of up to 13 h. The HRT was determined as an important variable affecting catechol removal from wastewater. Reducing the HRT to below 13 h led to reduced removal of catechol and COD.

  4. Biological degradation of catechol in wastewater using the sequencing continuous-inflow reactor (SCR)

    PubMed Central

    2013-01-01

    Catechol is used in many industries. It can be removed from wastewater by various methods but biological processes are the most superior and commonly used technology. The SCR is a modified form of SBR used to degrade catechol. The objective of this study was to investigate the performance of SCR for biodegradation and mineralization of catechol under various inlet concentrations (630–1500 mg/L) and hydraulic retention times (HRT) (18–9 h). This study used a bench scale SCR setup to test catechol degradation. The acclimation time of biomass for catechol at degradation at 630 mg/L was 41 d. The SCR operating cycle time was 6 h and the consecutive times taken for aerating, settling and decanting were 4, 1.5 and 0.5 h, respectively. This study investigated the effects of inlet catechol concentration (630–1560 mg/L) and HRT (18–9 h). The average catechol removal efficiencies in steady-state conditions of 630, 930, 12954 and 1559 mg/L of catechol were 98.5%, 98.5%, 98.2% and 96.9% in terms catechol and 97.8%, 97.7%, 96.4% and 94.3% for COD, respectively. SCR with acclimated biomasses could effectively remove the catechol and the corresponding COD from wastewater with concentrations of up to 1560, at the loading rate of 5.38 kg COD/m3.d and at a HRT of up to 13 h. The HRT was determined as an important variable affecting catechol removal from wastewater. Reducing the HRT to below 13 h led to reduced removal of catechol and COD. PMID:24499534

  5. An enzyme-based DNA preparation method for application to forensic biological samples and degraded stains.

    PubMed

    Lounsbury, Jenny A; Coult, Natalie; Miranian, Daniel C; Cronk, Stephen M; Haverstick, Doris M; Kinnon, Paul; Saul, David J; Landers, James P

    2012-09-01

    Extraction of DNA from forensic samples typically uses either an organic extraction protocol or solid phase extraction (SPE) and these methods generally involve numerous sample transfer, wash and centrifugation steps. Although SPE has been successfully adapted to the microdevice, it can be problematic because of lengthy load times and uneven packing of the solid phase. A closed-tube enzyme-based DNA preparation method has recently been developed which uses a neutral proteinase to lyse cells and degrade proteins and nucleases [14]. Following a 20 min incubation of the buccal or whole blood sample with this proteinase, DNA is polymerase chain reaction (PCR)-ready. This paper describes the optimization and quantitation of DNA yield using this method, and application to forensic biological samples, including UV- and heat-degraded whole blood samples on cotton or blue denim substrates. Results demonstrate that DNA yield can be increased from 1.42 (±0.21)ng/μL to 7.78 (±1.40)ng/μL by increasing the quantity of enzyme per reaction by 3-fold. Additionally, there is a linear relationship between the amount of starting cellular material added and the concentration of DNA in the solution, thereby allowing DNA yield estimations to be made. In addition, short tandem repeat (STR) profile results obtained using DNA prepared with the enzyme method were comparable to those obtained with a conventional SPE method, resulting in full STR profiles (16 of 16 loci) from liquid samples (buccal swab eluate and whole blood), dried buccal swabs and bloodstains and partial profiles from UV or heat-degraded bloodstains on cotton or blue denim substrates. Finally, the DNA preparation method is shown to be adaptable to glass or poly(methyl methacrylate) (PMMA) microdevices with little impact on STR peak height but providing a 20-fold reduction in incubation time (as little as 60 s), leading to a ≥1 h reduction in DNA preparation time.

  6. Experimental Fluidic Investigation of Degradation of Pico-liter Oil Droplets by Physical and Biological Processes

    NASA Astrophysics Data System (ADS)

    Jalali, Maryam; Sheng, Jian

    2016-11-01

    This study used laboratory experiments to assess degradation of crude oil by physical and biological processes including dissolution and consumption. To perform this study, we have developed a bioassay that consists of a flow chamber with a bottom glass substrate printed with an array of pico-liter oil droplets using micro-Transfer Printing. The technique allows the printing of highly homogeneous pico-liter droplet array with different dimensions and shapes that can be maintained for weeks. Since the droplets are pinned and stationary on the bottom substrate, the key processes can be evaluated by measuring the change of shape and volume using Atomic Force Microscopy. Parallel microfluidic bioassays are established at the beginning, exposed to abiotic/biotic solutions, and scarified for characterization at given time intervals for each experiment. Two processes, dissolution and consumption, are investigated. In addition, the effects of dispersant on these processes are also studied. The results show that the amount of oil degraded by bacteria accounts for almost 50% of the total volume in comparison to 25% via dissolution. Although dispersant has a subtle effect on dissolution, the effect on rates of consumption and its asymptotic behavior are substantial. Experiments involving different bacterial strains, dispersant concentration, and flow shear rate are on-going.

  7. Degraded lands worth protecting: the biological importance of Southeast Asia's repeatedly logged forests.

    PubMed

    Edwards, David P; Larsen, Trond H; Docherty, Teegan D S; Ansell, Felicity A; Hsu, Wayne W; Derhé, Mia A; Hamer, Keith C; Wilcove, David S

    2011-01-07

    Southeast Asia is a hotspot of imperiled biodiversity, owing to extensive logging and forest conversion to oil palm agriculture. The degraded forests that remain after multiple rounds of intensive logging are often assumed to be of little conservation value; consequently, there has been no concerted effort to prevent them from being converted to oil palm. However, no study has quantified the biodiversity of repeatedly logged forests. We compare the species richness and composition of birds and dung beetles within unlogged (primary), once-logged and twice-logged forests in Sabah, Borneo. Logging had little effect on the overall richness of birds. Dung beetle richness declined following once-logging but did not decline further after twice-logging. The species composition of bird and dung beetle communities was altered, particularly after the second logging rotation, but globally imperiled bird species (IUCN Red List) did not decline further after twice-logging. Remarkably, over 75 per cent of bird and dung beetle species found in unlogged forest persisted within twice-logged forest. Although twice-logged forests have less biological value than primary and once-logged forests, they clearly provide important habitat for numerous bird and dung beetle species. Preventing these degraded forests from being converted to oil palm should be a priority of policy-makers and conservationists.

  8. Enhanced biological straw saccharification through coculturing of lignocellulose-degrading microorganisms.

    PubMed

    Taha, Mohamed; Shahsavari, Esmaeil; Al-Hothaly, Khalid; Mouradov, Aidyn; Smith, Andrew T; Ball, Andrew S; Adetutu, Eric M

    2015-04-01

    Lignocellulosic waste (LCW) is an abundant, low-cost, and inedible substrate for the induction of lignocellulolytic enzymes for cellulosic bioethanol production using an efficient, environmentally friendly, and economical biological approach. In this study, 30 different lignocellulose-degrading bacterial and 18 fungal isolates were quantitatively screened individually for the saccharification of four different ball-milled straw substrates: wheat, rice, sugarcane, and pea straw. Rice and sugarcane straws which had similar Fourier transform-infrared spectroscopy profiles were more degradable, and resulted in more hydrolytic enzyme production than wheat and pea straws. Crude enzyme produced on native straws performed better than those on artificial substrates (such as cellulose and xylan). Four fungal and five bacterial isolates were selected (based on their high strawase activities) for constructing dual and triple microbial combinations to investigate microbial synergistic effects on saccharification. Combinations such as FUNG16-FUNG17 (Neosartorya fischeri-Myceliophthora thermophila) and RMIT10-RMIT11 (Aeromonas hydrophila-Pseudomonas poae) enhanced saccharification (3- and 6.6-folds, respectively) compared with their monocultures indicating the beneficial effects of synergism between those isolates. Dual isolate combinations were more efficient at straw saccharification than triple combinations in both bacterial and fungal assays. Overall, co-culturing can result in significant increases in saccharification which may offer significant commercial potential for the use of microbial consortia.

  9. Degradation of pharmaceuticals from membrane biological reactor sludge with Trametes versicolor.

    PubMed

    Llorens-Blanch, Guillem; Badia-Fabregat, Marina; Lucas, Daniel; Rodriguez-Mozaz, Sara; Barceló, Damià; Pennanen, Taina; Caminal, Gloria; Blánquez, Paqui

    2015-02-01

    Emerging contaminants are a wide group of chemical products that are found at low concentrations in the environment. These contaminants can be either natural, e.g., estrogens, or synthetics, such as pesticides and pharmaceuticals, which can enter the environment through the water and sludge from wastewater treatment plants (WWTP). The growth of Trametes versicolor on membrane biological reactor (MBR) sludge in bioslurry systems at the Erlenmeyer scale was assessed and its capacity for removing pharmaceutical and personal care products (PPCPs) was evaluated. The ability of the fungus to remove hydrochlorothiazide (HZT) from liquid media cultures was initially assessed. Consequently, different bioslurry media (complete nutrient, glucose and no-nutrient addition) and conditions (sterile and non-sterile) were tested, and the removal of spiked HZT was monitored under each condition. The highest spiked HZT removal was assessed under non-sterile conditions without nutrient addition (93.2%). Finally, the removal assessment of a broad set of pharmaceuticals was performed in non-spiked bioslurry. Under non-sterile conditions, the fungus was able to completely degrade 12 out of the 28 drugs initially detected in the MBR sludge, achieving an overall degradation of 66.9%. Subsequent microbial analysis showed that the microbial diversity increased after 15 days of treatment, but there was still some T. versicolor in the bioslurry. Results showed that T. versicolor can be used to remove PPCPs in bioslurry systems under non-sterile conditions, without extra nutrients in the media, and in matrices as complex as an MBR sludge.

  10. Recent updates on electrochemical degradation of bio-refractory organic pollutants using BDD anode: a mini review.

    PubMed

    Yu, Xinmin; Zhou, Minghua; Hu, Youshuang; Groenen Serrano, K; Yu, Fangke

    2014-01-01

    Boron-doped diamond (BDD) is playing an important role in environmental electrochemistry and has been successfully applied to the degradation of various bio-refractory organic pollutants. However, the review concerning recent progress in this research area is still very limited. This mini-review updated recent advances on the removal of three kinds of bio-refractory wastewaters including pharmaceuticals, pesticides, and dyes using BDD electrode. It summarized the important parameters in three electrochemical oxidation processes, i.e., anodic oxidation (AO), electro-Fenton (EF), and photoelectro-Fenton (PEF) and compared their different degradation mechanisms and behaviors. As an attractive improvement of PEF, solar photoelectro-Fenton using sunlight as UV/vis source presented cost-effectiveness, in which the energy consumption for enrofloxacin removal was 0.246 kWh/(g TOC), which was much lower than that of 0.743 and 0.467 kWh/(g TOC) by AO and EF under similar conditions. Finally the existing problems and future prospects in research were suggested.

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

    PubMed

    Chronopoulou, Panagiota-Myrsini; Sanni, Gbemisola O; Silas-Olu, Daniel I; van der Meer, Jan Roelof; Timmis, Kenneth N; Brussaard, Corina P D; McGenity, Terry J

    2015-05-01

    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-induced changes in bacterial community (3 m below the sea surface) were observed 32 h after the experimental spill at sea. In contrast, there was a decrease in the dominant SAR11 phylotype and an increase in Pseudoalteromonas spp. in the oiled mesocosms (investigated by 16S rRNA gene analysis using denaturing gradient gel electrophoresis), as a consequence of the longer incubation, closer proximity of the samples to oil, and the lack of replenishment with seawater. A total of 216 strains were isolated from hydrocarbon enrichment cultures, predominantly belonging to the genus Pseudoaltero monas; most strains grew on PAHs, branched and straight-chain alkanes, as well as many other carbon sources. No obligate hydrocarbonoclastic bacteria were isolated or detected, highlighting the potential importance of cosmopolitan marine generalists like Pseudoalteromonas spp. in degrading hydrocarbons in the water column beneath an oil slick, and revealing the susceptibility to oil pollution of SAR11, the most abundant bacterial clade in the surface ocean.

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

    PubMed Central

    Chronopoulou, Panagiota-Myrsini; Sanni, Gbemisola O; Silas-Olu, Daniel I; van der Meer, Jan Roelof; Timmis, Kenneth N; Brussaard, Corina P D; McGenity, Terry 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-induced changes in bacterial community (3 m below the sea surface) were observed 32 h after the experimental spill at sea. In contrast, there was a decrease in the dominant SAR11 phylotype and an increase in Pseudoalteromonas spp. in the oiled mesocosms (investigated by 16S rRNA gene analysis using denaturing gradient gel electrophoresis), as a consequence of the longer incubation, closer proximity of the samples to oil, and the lack of replenishment with seawater. A total of 216 strains were isolated from hydrocarbon enrichment cultures, predominantly belonging to the genus Pseudoaltero monas; most strains grew on PAHs, branched and straight-chain alkanes, as well as many other carbon sources. No obligate hydrocarbonoclastic bacteria were isolated or detected, highlighting the potential importance of cosmopolitan marine generalists like Pseudoalteromonas spp. in degrading hydrocarbons in the water column beneath an oil slick, and revealing the susceptibility to oil pollution of SAR11, the most abundant bacterial clade in the surface ocean. PMID:25251384

  13. Use of bromodeoxyuridine immunocapture to identify psychrotolerant phenanthrene-degrading bacteria in phenanthrene-enriched polluted Baltic Sea sediments

    SciTech Connect

    Edlund, A.; Jansson, J.

    2008-05-01

    The aim of this study was to enrich and identify psychrotolerant phenanthrenedegrading bacteria from polluted Baltic Sea sediments. Polyaromatic hydrocarbon (PAH)-contaminated sediments were spiked with phenanthrene and incubated for 2 months in the presence of bromodeoxyuridine that is incorporated into the DNA of replicating cells. The bromodeoxyuridine-incorporated DNA was extracted by immunocapture and analyzed by terminal-restriction fragment length polymorphism and 16S rRNA gene cloning and sequencing to identify bacterial populations that were growing. In addition, degradation genes were quantified in the bromodeoxyuridine-incorporated DNA by real-time PCR. Phenanthrene concentrations decreased after 2 months of incubation in the phenanthrene-enriched sediments and this reduction correlated to increases in copy numbers of xylE and phnAc dioxygenase genes. Representatives of Exiguobacterium, Schewanella,Methylomonas, Pseudomonas, Bacteroides and an uncultured Deltaproteobacterium and a Gammaproteobacterium dominated the growing community in the phenanthrene spiked sediments. Isolates that were closely related to three of these bacteria (two pseudomonads and an Exiguobacterium sp.) could reduce phenanthrene concentrations in pure cultures and they all harbored phnAc dioxygenase genes. These results confirm that this combination of culture-based and molecular approaches was useful for identification of actively growing bacterial species with a high potential for phenanthrene degradation.

  14. Efficient peroxydisulfate activation process not relying on sulfate radical generation for water pollutant degradation.

    PubMed

    Zhang, Tao; Chen, Yin; Wang, Yuru; Le Roux, Julien; Yang, Yang; Croué, Jean-Philippe

    2014-05-20

    Peroxydisulfate (PDS) is an appealing oxidant for contaminated groundwater and toxic industrial wastewaters. Activation of PDS is necessary for application because of its low reactivity. Present activation processes always generate sulfate radicals as actual oxidants which unselectively oxidize organics and halide anions reducing oxidation capacity of PDS and producing toxic halogenated products. Here we report that copper oxide (CuO) can efficiently activate PDS under mild conditions without producing sulfate radicals. The PDS/CuO coupled process is most efficient at neutral pH for decomposing a model compound, 2,4-dichlorophenol (2,4-DCP). In a continuous-flow reaction with an empty-bed contact time of 0.55 min, over 90% of 2,4-DCP (initially 20 μM) and 90% of adsorbable organic chlorine (AOCl) can be removed at the PDS/2,4-DCP molar ratio of 1 and 4, respectively. Based on kinetic study and surface characterization, PDS is proposed to be first activated by CuO through outer-sphere interaction, the rate-limiting step, followed by a rapid reaction with 2,4-DCP present in the solution. In the presence of ubiquitous chloride ions in groundwater/industrial wastewater, the PDS/CuO oxidation shows significant advantages over sulfate radical oxidation by achieving much higher 2,4-DCP degradation capacity and avoiding the formation of highly chlorinated degradation products. This work provides a new way of PDS activation for contaminant removal.

  15. Physicochemical and porosity characteristics of thermally regenerated activated carbon polluted with biological activated carbon process.

    PubMed

    Dong, Lihua; Liu, Wenjun; Jiang, Renfu; Wang, Zhansheng

    2014-11-01

    The characteristics of thermally regenerated activated carbon (AC) polluted with biological activated carbon (BAC) process were investigated. The results showed that the true micropore and sub-micropore volume, pH value, bulk density, and hardness of regenerated AC decreased compared to the virgin AC, but the total pore volume increased. XPS analysis displayed that the ash contents of Al, Si, and Ca in the regenerated AC respectively increased by 3.83%, 2.62% and 1.8%. FTIR spectrum showed that the surface functional groups of virgin and regenerated AC did not change significantly. Pore size distributions indicated that the AC regeneration process resulted in the decrease of micropore and macropore (D>10 μm) volume and the increase of mesopore and macropore (0.1 μmbiological waste (spent AC) from BAC process.

  16. Functional genomics to assess biological responses to marine pollution at physiological and evolutionary timescales: toward a vision of predictive ecotoxicology.

    PubMed

    Reid, Noah M; Whitehead, Andrew

    2016-09-01

    Marine pollution is ubiquitous, and is one of the key factors influencing contemporary marine biodiversity worldwide. To protect marine biodiversity, how do we surveil, document and predict the short- and long-term impacts of pollutants on at-risk species? Modern genomics tools offer high-throughput, information-rich and increasingly cost-effective approaches for characterizing biological responses to environmental stress, and are important tools within an increasing sophisticated kit for surveiling and assessing impacts of pollutants on marine species. Through the lens of recent research in marine killifish, we illustrate how genomics tools may be useful for screening chemicals and pollutants for biological activity and to reveal specific mechanisms of action. The high dimensionality of transcriptomic responses enables their usage as highly specific fingerprints of exposure, and these fingerprints can be used to diagnose environmental problems. We also emphasize that molecular pathways recruited to respond at physiological timescales are the same pathways that may be targets for natural selection during chronic exposure to pollutants. Gene complement and sequence variation in those pathways can be related to variation in sensitivity to environmental pollutants within and among species. Furthermore, allelic variation associated with evolved tolerance in those pathways could be tracked to estimate the pace of environmental health decline and recovery. We finish by integrating these paradigms into a vision of how genomics approaches could anchor a modernized framework for advancing the predictive capacity of environmental and ecotoxicological science.

  17. Genome Sequences of Two Naphthalene-Degrading Strains of Pseudomonas balearica, Isolated from Polluted Marine Sediment and from an Oil Refinery Site

    PubMed Central

    Jakobsson, Hedvig E.; Busquets, Antonio; Gomila, Margarita; Jaén-Luchoro, Daniel; Seguí, Carolina; Aliaga-Lozano, Francisco; García-Valdés, Elena; Lalucat, Jorge

    2017-01-01

    ABSTRACT The genome sequences of Pseudomonas balearica strains LS401 (CCUG 66666) and st101 (CCUG 66667) have been determined. The strains were isolated as naphthalene degraders from polluted marine sediment and from a sample from an oil refinery site, respectively. These genomes provide essential data about the biodegradation capabilities and the ecological implications of P. balearica. PMID:28385841

  18. Effects of pollutant accumulation by the invasive weed saltcedar (Tamarix ramosissima) on the biological control agent Diorhabda elongata (Coleoptera: Chrysomelidae).

    PubMed

    Sorensen, Mary A; Parker, David R; Trumble, John T

    2009-02-01

    Hydroponic greenhouse studies were used to investigate the effect of four anthropogenic pollutants (perchlorate (ClO4(-)), selenium (Se), manganese (Mn), and hexavalent chromium (Cr (VI))) on the biological control agent Diorhabda elongata Brullé. Contaminant concentrations were quantified for experimental Tamarix ramosissima Ledab. plants and D. elongata beetles. Growth of larvae was significantly reduced by Se contamination, but was not affected by the presence of perchlorate, Mn, or Cr (VI). All of the contaminants were transferred from plants to D. elongata beetles. Only Cr (VI) was accumulated at greater levels in beetles than in their food. Because T. ramosissima grows in disturbed areas, acquires salts readily, and utilizes groundwater, this plant is likely to accumulate anthropogenic pollutants in contaminated areas. This study is one of the first to investigate the potential of an anthropogenic pollutant to influence a weed biological control system.

  19. Benthic macroalgae as biological indicators of heavy metal pollution in the marine environments: a biomonitoring approach for pollution assessment.

    PubMed

    Chakraborty, Sukalyan; Bhattacharya, Tanushree; Singh, Gurmeet; Maity, Jyoti Prakash

    2014-02-01

    Metal pollution in the marine coastline environment is an important topical issue in the context of ecological disturbance and climate change. Heavy metal contaminations (Cd, Cr, Cu, Mn, Ni, Pb and Zn) in seawater and surficial sediments, as well as macroalgal diversity, were determined in six different locations along the coast of the Gulf of Kutch in India. The marine coastline environment was found to be enriched with Cd and Zn in comparison to other metals. Significant (p ≤ 0.05) inter-elemental positive-correlations were observed between Fe-Mn, Fe-Cu, Fe-Cr, Fe-Zn, Cr-Cu, Cu-Mn, and Cd-Zn, as well as negative-correlations between Cd-Pb, Ni-Pb, and Zn-Pb. Though genus specific macroalgal responses to heavy metal accumulation were significant, species specific response was insignificant (p ≤ 0.05). The relative abundance of metals in macroalgae followed the order of Fe>Zn>Mn>Cu>Cd>Cr>Ni>Pb. The high uptake of metals in green algae (Ulva lactuca and Enteromorpha intestinalis) and brown algae (Padina gymnospora and Dictyota bartayresiana) suggested that these algae may be used as potential biomonitors for heavy metal pollution. Three pollution indicators, Contamination Factor (CF), Enrichment Factor (EF) and Geochemical Index (Igeo) were calculated to determine the degree of metal pollution in the marine coastline and the contribution of anthropogenic influence.

  20. Investigating groundwater pollution from different sources with combined biological and chemical methods.

    PubMed

    Michaelidou, S C; Akkelidou, D; Ziegler, P

    1995-10-27

    This paper reviews groundwater pollution caused by the disposal of untreated effluents of a dye factory located 20 km to the west of Nicosia (Cyprus). The task of the work was to investigate the nature of the pollution and differentiate it from other possible pollution sources in the area. It focused on toxicity testing and biofractionation in order to address the most toxic pollutants and, on the evaluation of GC/FID profiles for investigating the connection between groundwater pollution and the effluents. This connection was successful due to a multiple comparison amongst the GC/FID profiles resulting from the polluted groundwater, the water from the reference areas and the dye effluents.

  1. Environmental and biological monitoring of arsenic in outdoor workers exposed to urban air pollutants.

    PubMed

    Ciarrocca, Manuela; Tomei, Gianfranco; Palermo, Paola; Caciari, Tiziana; Cetica, Carlotta; Fiaschetti, Maria; Gioffrè, Pier Agostino; Tasciotti, Zaira; Tomei, Francesco; Sancini, Angela

    2012-11-01

    The aim of this study is to evaluate personal exposure to As in urban air in two groups of outdoor workers (traffic policemen and police drivers) of a big Italian city through: (a) environmental monitoring of As obtained by personal samples and (b) biological monitoring of total urinary As. The possible influence of smoking habit on urinary As was evaluated. We studied 122 male subjects, all Municipal Police employees: 84 traffic policemen and 38 police drivers exposed to urban pollutants. Personal exposure to As in air was significantly higher in traffic policemen than in police drivers (p=0.03). Mean age, length of service, alcohol drinking habit, number of cigarettes smoked/day and BMI were comparable between the groups of subjects studied. All subjects were working in the same urban area where they had lived for at least 5 yrs. Dietary habits and consumption of water from the water supply and/or mineral water were similar in traffic policemen and in police drivers. The values of total urinary As were significantly higher in traffic policemen (smokers and non smokers) than in police drivers (smokers and non smokers) (p=0.02). In the subgroup of non-smokers the values of total urinary As were significantly higher in traffic policemen than in police drivers (p=0.03). In traffic policemen and in police drivers total urinary As values were significantly correlated to the values of As in air (respectively r=0.9 and r=0.8, p<0.001). This is the first research in literature studying the exposure to As in outdoor workers occupationally exposed to urban pollutants, such as traffic policemen and police drivers. Personal exposure to As in the air, as well as the urinary excretion of As, is significantly higher in traffic policemen compared to drivers. These results can provide information about exposure to As in streets and in car for other categories of outdoor workers similarly exposed.

  2. Photocatalytic degradation of phenolic pollutants over TiO{sub 2} semiconductor with various structures

    SciTech Connect

    Tsai, Shi-Jane; Cheng, Soofin

    1995-12-31

    The photocatalytic activities of titanium oxides with various structures in the decomposition of phenolic pollutants in aqueous solutions were studied. The structures of titanium oxide included crystalline anatase and rutile TiO{sub 2} phase either commercially available or laboratory-made, layered titanates, small titanium oxide crystallites pillared in the clay interlayers, and titanium oxide impregnated on silica gel. The catalytic activities were compared based on the same titanium content as 0.01 g TiO{sub 2} suspended in 50 mL of 1.25 mM aqueous solutions containing phenolic compounds, with O{sub 2} gas of 10 mL/min as oxidant and illumination with 300 nm UV radiation. The reactions adopted the Langmuir-Hinshelwood kinetics model. The results showed that high conversion was observed over the commercialized anatase, laboratory-made TiO{sub 2} of anatase or rutile phase, and the silica gel supported TiO{sub 2}. For laboratory-made anatase and rutile, the activities were changed with calcination temperatures, probably clue to the variation in particle sizes. On the other hand, the activities of all the catalysts with layered structures were low. The strong interaction between the charged surfaces and the phenolic intermediates was proposed to be the main reason for coke formation and low activities over commercialized rutile and the layered catalysts.

  3. Re-inoculation strategies enhance the degradation of emerging pollutants in fungal bioaugmentation of sewage sludge.

    PubMed

    Rodríguez-Rodríguez, Carlos E; Lucas, Daniel; Barón, Enrique; Gago-Ferrero, Pablo; Molins-Delgado, Daniel; Rodríguez-Mozaz, Sara; Eljarrat, Ethel; Díaz-Cruz, M Silvia; Barceló, Damià; Caminal, Glòria; Vicent, Teresa

    2014-09-01

    The use of Trametes versicolor has been partially successful in the removal of some pharmaceuticals from sewage sludge in laboratory-scale biopile systems. The application of two strategies for the re-inoculation of biomass was assessed during the fungal bioaugmentation of non-sterile sludge (42-d treatment) as an approach to improve the elimination of pharmaceuticals and other groups of emerging pollutants. Globally, the re-inoculation of biopiles with blended mycelium exerted a major effect on the removal of pharmaceuticals (86%), brominated-flame-retardants (81%) and UV filters (80%) with respect to the re-inoculation with additional lignocellulosic substrate colonized by the fungus (69-67-22%). The performance was better than that of the analogous non-re-inoculated systems that were assayed previously for the removal of pharmaceuticals. The results demonstrate the ability of T. versicolor to remove a wide spectrum of emerging micropollutants under non-sterile conditions, while re-inoculation appears to be a useful step to improve the fungal treatment of sludge.

  4. Structural Basis of the Enhanced Pollutant-Degrading Capabilities of an Engineered Biphenyl Dioxygenase

    PubMed Central

    Dhindwal, Sonali; Gomez-Gil, Leticia; Neau, David B.; Pham, Thi Thanh My; Sylvestre, Michel; Eltis, Lindsay D.; Bolin, Jeffrey T.

    2016-01-01

    ABSTRACT Biphenyl dioxygenase, the first enzyme of the biphenyl catabolic pathway, is a major determinant of which polychlorinated biphenyl (PCB) congeners are metabolized by a given bacterial strain. Ongoing efforts aim to engineer BphAE, the oxygenase component of the enzyme, to efficiently transform a wider range of congeners. BphAEII9, a variant of BphAELB400 in which a seven-residue segment, 335TFNNIRI341, has been replaced by the corresponding segment of BphAEB356, 333GINTIRT339, transforms a broader range of PCB congeners than does either BphAELB400 or BphAEB356, including 2,6-dichlorobiphenyl, 3,3′-dichlorobiphenyl, 4,4′-dichlorobiphenyl, and 2,3,4′-trichlorobiphenyl. To understand the structural basis of the enhanced activity of BphAEII9, we have determined the three-dimensional structure of this variant in substrate-free and biphenyl-bound forms. Structural comparison with BphAELB400 reveals a flexible active-site mouth and a relaxed substrate binding pocket in BphAEII9 that allow it to bind different congeners and which could be responsible for the enzyme's altered specificity. Biochemical experiments revealed that BphAEII9 transformed 2,3,4′-trichlorobiphenyl and 2,2′,5,5′-tetrachlorobiphenyl more efficiently than did BphAELB400 and BphAEB356. BphAEII9 also transformed the insecticide dichlorodiphenyltrichloroethane (DDT) more efficiently than did either parental enzyme (apparent kcat/Km of 2.2 ± 0.5 mM−1 s−1, versus 0.9 ± 0.5 mM−1 s−1 for BphAEB356). Studies of docking of the enzymes with these three substrates provide insight into the structural basis of the different substrate selectivities and regiospecificities of the enzymes. IMPORTANCE Biphenyl dioxygenase is the first enzyme of the biphenyl degradation pathway that is involved in the degradation of polychlorinated biphenyls. Attempts have been made to identify the residues that influence the enzyme activity for the range of substrates among various species. In this study

  5. Kinetic degradation of the pollutant guaiacol by dark Fenton and solar photo-Fenton processes.

    PubMed

    Samet, Youssef; Wali, Ines; Abdelhédi, Ridha

    2011-11-01

    This work is first intended to optimize the experimental conditions for the maximum degradation of guaiacol (2-methoxyphenol) by Fenton's reagent, and second, to improve the process efficiency through the use of solar radiation. Guaiacol is considered as a model compound of pulp and paper mill effluent. The experiments were carried out in a laboratory-scale reactor subjected or not to solar radiation. Hydrogen peroxide solution was continuously introduced into the reactor at a constant flow rate. The kinetics of organic matter decay was evaluated by means of the chemical oxygen demand (COD) and the absorbance measurements. The experimental results showed that the Fenton and solar photo-Fenton systems lead successfully to 90% elimination of COD and absorbance at 604 nm from a guaiacol solution under particular experimental conditions. The COD removal always obeyed a pseudo-first-order kinetics. The effect of pH, temperature, H(2)O(2) dosing rate, initial concentration of Fe(2+), and initial COD was investigated using the Fenton process. The solar photo-Fenton system needed less time and consequently less quantity of H(2)O(2). Under the optimum experimental conditions, the solar photo-Fenton process needs a dose of H(2)O(2) 40% lower than that used in the Fenton process to remove 90% of COD.

  6. Biological monitoring of aromatic diisocyanates in workers exposed to thermal degradation products of polyurethanes.

    PubMed

    Rosenberg, Christina; Nikkilä, Kirsi; Henriks-Eckerman, Maj-Len; Peltonen, Kimmo; Engströrm, Kerstin

    2002-10-01

    Exposure to diisocyanates was assessed by biological monitoring among workers exposed to the thermal degradation products of polyurethanes (PURs) in five PUR-processing environments. The processes included grinding and welding in car repair shops, milling and turning of PUR-coated metal cylinders, injection moulding of thermoplastic PUR, welding and cutting of PUR-insulated district heating pipes during installation and joint welding, and heat-flexing of PUR floor covering. Isocyanate-derived amines in acid-hydrolysed urine samples were analysed as perfluoroacylated derivatives by gas chromatography mass spectrometry in negative chemical ionisation mode. The limits of quantification (LOQs) for the aromatic diamines 2,4- and 2,6-toluenediamine (2,4- and 2,6-TDA) and 4,4'-methylenedianiline (4,4'-MDA) were 0.25 nmol l(-1), 0.25 nmol l(-1) and 0.15 nmol l(-1), respectively. The LOQ for the aliphatic diamines hexamethylenediamine (HDA), isophoronediamine (IpDA) and 4,4'-diaminodicyclohexyl methane (4,4'-DDHM) was 5 nmol l(-1). TDA and MDA were detected in urine samples from workers in car repair shops and MDA in samples from workers welding district heating pipes. The 2,4-TDA isomer accounted for about 80% of the total TDA detected. No 2.6-TDA was found in the urine of non-exposed workers. The highest measured urinary TDA and MDA concentrations were 0.79 nmol mmol(-1) creatinine and 3.1 nmol mmol(-1) creatinine, respectively. The concentrations found among non-exposed workers were 0.08 nmol mmol(-1) creatinine for TDA and 0.05 nmol mmol(-1) creatinine for MDA (arithmetic means). Exposure to diisocyanates originating from the thermal degradation of PURs are often intermittent and of short duration. Nevertheless, exposure to aromatic diisocyanates can be identified by monitoring diisocyanate-derived amines in acid-hydrolysed urine samples.

  7. Effect of dry deposition of pollutants on the degradation of lime mortars with sepiolite

    SciTech Connect

    Martinez-Ramirez, S.; Thompson, G.E.; Puertas, F.; Blanco-Varela, M.T.

    1998-01-01

    The behavior of lime mortars containing sepiolite or sepiolite plus pentaclorophenol in atmospheric simulation chambers has been studied. The pollutant gases used in this study have been NO, NO{sub 2}, and SO{sub 2}. The studies have been done in wet and dry conditions as well as with and without ozone. In the case of NO and NO{sub 2}, the aggressive agent would be HNO{sub 3}, which reacts with lime mortar binder CaCO{sub 3}, producing Ca(NO{sub 3}){sub 2} formation. On this process, the influence of the presence of an oxidant as well as water has been studied. The catalyst effect of the oxidation is known to be accelerated by water presence, so mortars exposed to NO + O{sub 3} + H{sub 2}O and NO{sub 2} + O{sub 3} + H{sub 2}O environments undergo a greater salts formation than those exposed to the rest of he aggressive media. The three mortars` behaviors are similar and independent of their composition, producing small amount of salts in every case. When SO{sub 2} is the gas used, the aggressive agent of mortar will be H{sub 2}SO{sub 4} that reacts with mortar binder, CaCO{sub 3} to produce calcium sulfate in the form of gypsum. Oxidant and/or water influence has been studied, and the (SO{sub 2} + O{sub 3} + H{sub 2}O) chamber was found to be the one with greater aggressivity to mortars. However, in these conditions, sepiolite presence within the mortars delayed gypsum formation.

  8. PHOTOCHEMICAL AND BIOLOGICAL DEGRADATION OF CDOM IN WATERS FROM SELECTED COASTAL REGIONS OF THE SOUTHEASTERN UNITED STATES

    EPA Science Inventory

    Biological and photochemical degradation of colored dissolved organic matter (CDOM) were investigated in controlled experiments using waters from southeastern U.S. estuaries, from the Mississippi River plume and Gulf of Mexico, and from the coastal shelf region in the Florida Key...

  9. CARBON LOSS AND OPTICAL PROPERTY CHANGES DURING LONG-TERM PHOTOCHEMICAL AND BIOLOGICAL DEGRADATION OF ESTUARINE DISSOLVED ORGANIC MATTER

    EPA Science Inventory

    Terrestrially derived dissolved organic matter (DOM) impacts the optical properties of coastal seawater and affects carbon cycling on a global scale. We studied sequential long-term photochemical and biological degradation of estuarine dissolved organic matter from the
    Satilla...

  10. Enzymatic degradation of endocrine-disrupting chemicals in aquatic plants and relations to biological Fenton reaction.

    PubMed

    Reis, A R; Sakakibara, Y

    2012-01-01

    In order to evaluate the removal performance of trace phenolic endocrine-disrupting chemicals (EDCs) by aquatic plants, batch and continuous experiments were conducted using floating and submerged plants. The EDCs used in this study were bisphenol A, 2,4-dichlorophenol, 4-tert-octylphenol, pentachlorophenol, and nonylphenol. The feed concentration of each EDC was set at 100 μg/L. Continuous experiments showed that every EDC except pentachlorophenol was efficiently removed by different aquatic plants through the following reaction, catalyzed by peroxidases: EDCs+H(2)O(2)→Products+H(2)O(2). Peroxidases were able to remove phenolic EDCs in the presence of H(2)O(2) over a wide pH range (from 3 to 9). Histochemical localization of peroxidases showed that they were located in every part of the root cells, while highly concentrated zones were observed in the epidermis and in the vascular tissues. Although pentachlorophenol was not removed in the continuous treatment, it was rapidly removed by different aquatic plants when Fe(2+) was added, and this removal occurred simultaneously with the consumption of endogenous H(2)O(2). These results demonstrated the occurrence of a biological Fenton reaction and the importance of H(2)O(2) as a key endogenous substance in the treatment of EDCs and refractory toxic pollutants.

  11. Applications of Cu{sub 2}O octahedral particles on ITO glass in photocatalytic degradation of dye pollutants under a halogen tungsten lamp

    SciTech Connect

    Zhai, Wei; Sun, Fengqiang; Chen, Wei; Zhang, Lihe; Min, Zhilin; Li, Weishan

    2013-11-15

    Graphical abstract: - Highlights: • Photocatalytic activity of Cu{sub 2}O octahedral microcrystals on ITO glass was studied. • They showed high abilities in degradation of methylene blue in the presence of H{sub 2}O{sub 2}. • H{sub 2}O{sub 2} amount could affect the degradation efficiency. • Such particles could be easily recycled and still kept high activity. • Many dye pollutants and their mixtures could be efficiently degraded. - Abstract: Cu{sub 2}O octahedral microcrystals were prepared on the ITO glass by galvanostatic electrodeposition in CuSO{sub 4} solution with poly(vinylpryrrolidone) as the surfactant. By controlling the electrodeposition time, the microcrystals could be randomly distributed on the ITO glass and separated from each other, resulting in as many as possible (1 1 1) crystalline planes were exposed. Such microcrystals immobilized on ITO glass were employed in photodegradation of dye pollutants in the presence of H{sub 2}O{sub 2} under a 150 W halogen tungsten lamp. The photodegradation of methylene blue was taken as an example to evaluate the photocatalytic activities of the octahedral Cu{sub 2}O microcrystals. Effects of electrodeposition time and H{sub 2}O{sub 2} amount on the degradation efficiency was discussed, giving the optimum conditions and the corresponding degradation mechanism. The catalyst showed high ability in degradation of methylene blue, methyl orange, rhodamine B, eosin B and their mixtures under identical conditions.

  12. [VOLATILE FATTY ACIDS IN SALIVA--BIOLOGICAL MARKERS FOR ASSESSMENT OF DRINKING WATER POLLUTANTS ON CHILDREN].

    PubMed

    Akaizina, A E; Akaizin, E S; Starodumov, V L

    2015-01-01

    The use of modern methods of analysis is aimed to the search of ultimately novel biological markers. Volatile fatty acids in saliva were not used previously for the assessment of the effects of contaminating substances in the drinking water on the body of children. The aim of the study is to investigate the informative value of volatile fatty acids in saliva as biological markers of the impact for the assessment of the exposure to contaminating substances in the drinking water on the body of children. Hygienic assessment of drinking water quality was made according to data of the own research of drinking water from centralized supply system of the city of Ivanovo. For the comparison of indices there was investigated the drinking water from wells at the village Podvyaznovsky of the Ivanovo region. In the Ivanovo water from the distributing network of centralized drinking water supply system of the city of Ivanovo, there were identified indices of the permanganate oxidation and the total concentration of residual chlorine exceeding norms, and also chloroform and carbon tetrachloride were in concentrations not exceeding the norms. Studied by us the samples of drinking water from Podvyaznovsky village wells, the water met the standards for all investigated parameters. The was studied the informative value of volatile fatty acids in the saliva of children aged 9-14 years from the city of Ivanovo and the Podvyaznovsky village, Ivanovo region. There was established the fall in acetic, butyric, isovaleric acids and the total amount of volatile fatty acids in the saliva in children of the city of Ivanovo, consuming water treated with chlorine of Ivanovo centralized drinking water supply system. Indices of volatile fatty acids in saliva are informative for the assessment of the impact of organic pollutants, residual chlorine and organic chlorine compounds of drinking water on the body of children.

  13. Marine biodegradation: Chemical pollutants. (Latest citations from Oceanic abstracts). Published Search

    SciTech Connect

    Not Available

    1993-03-01

    The bibliography contains citations concerning the biological degradation of marine pollutants. The citations explore the microbial breakdown of petroleum, herbicides, pesticides, polychlorinated biphenyls and other hazardous materials. The chemical details of biotransformation, and the development of microorganisms capable of degrading pollutants are presented. (Contains a minimum of 222 citations and includes a subject term index and title list.)

  14. Treatment of pharmaceutical wastewater using interior micro-electrolysis/Fenton oxidation-coagulation and biological degradation.

    PubMed

    Xu, Xiaoyi; Cheng, Yao; Zhang, Tingting; Ji, Fangying; Xu, Xuan

    2016-06-01

    The synthesis of steroid hormones produces wastewater that is difficult to manage and characterize due to its complex components and high levels of toxicity and bio-refractory compounds. In this work, interior micro-electrolysis (IME) and Fenton oxidation-coagulation (FOC) were investigated as wastewater pretreatment processes in combination with biological treatments using a hydrolysis acidification unit (HA) and two-stage biological contact oxidation (BCO) in laboratory and field experiments. In laboratory experiments with an average initial COD load of about 15,000 mg/L, pH of 4, Fe-C/water (V/V) ratio of 1:1, air/water ratio of 10, and reaction time of 180 min, IME achieved a COD removal efficiency of 31.8% and a 1.7-fold increase in the BOD5/COD (B/C) ratio of wastewater. The Fe(2+) concentration of 458.5 mg/L in the IME effluent meets the requirements of the Fenton oxidation (FO) process. FOC further reduced the COD with an efficiency of 30.1%, and the B/C ratio of the wastewater reached 0.59. Excitation-emission matrix (EEM) analysis showed that complex higher molecular weight organic compounds in the wastewater were degraded after the pretreatment process. In addition, a field experiment with a continuous flow of 96 m(3)/d was conducted for over 90 d. The combined process system operated steadily, though the Fe-C fillings should be soaked in a sulfuric acid solution (5‰) for 12 h to recover activity every two weeks. The COD and BOD5 concentrations in the final effluent were less than 90 mg/L and 15 mg/L, respectively.

  15. Distribution features of biological hazardous pollutants in residential environments in Korea.

    PubMed

    Lee, Cheol Min; Hong, Soo Jong; Kim, Yoon Shin; Park, Gee Yong; Nam Goung, Sun Ju; Kim, Kyung Hwan

    2014-01-01

    This research has been conducted continuously since 2009 as part of a cohort of studies examining relationships between asthma and genetic factors, dietary habits, and environmental factors. Based on data from environmental research on house dust mites and endotoxins, which are widely known as pollutants in bedding that cause asthma in pregnant women and children, this work was conducted to obtain basic data that can be used in future cohort studies that analyze links between distribution of biological hazards and physical features of residential environments. The detection rates of house dust mite allergens, Der p1 and Der f1, were 52.7 and 86.5%, respectively, indicating that Der f1 is a dominant species in domestic indoor environments. According to comparisons between concentrations of house dust mites and endotoxins in bedding of pregnant women and children, Der p1 and endotoxins showed significantly lower concentrations in bedding of pregnant women compared with those in bedding of children, whereas Der f1 showed no significant difference in concentration according to bedding.

  16. Biological Monitoring of Air Pollutants and Its Influence on Human Beings.

    PubMed

    Cen, Shihong

    2015-01-01

    Monitoring air pollutants via plants is an economic, convenient and credible method compared with the traditional ways. Plants show different damage symptoms to different air pollutants, which can be used to determine the species of air pollutants. Besides, pollutants mass concentration scope can be estimated by the damage extent of plants and the span of polluted time. Based on the domestic and foreign research, this paper discusses the principles, mechanism, advantages and disadvantages of plant-monitoring, and exemplifies plenty of such plants and the minimum mass concentration and pollution time of the plants showing damage symptoms. Finally, this paper introduced the human health effects of air pollutants on immune function of the body, such as decrease of the body's immune function, decline of lung function, respiratory and circulatory system changes, inducing and promoting human allergic diseases, respiratory diseases and other diseases.

  17. Water-driven micromotors for rapid photocatalytic degradation of biological and chemical warfare agents.

    PubMed

    Li, Jinxing; Singh, Virendra V; Sattayasamitsathit, Sirilak; Orozco, Jahir; Kaufmann, Kevin; Dong, Renfeng; Gao, Wei; Jurado-Sanchez, Beatriz; Fedorak, Yuri; Wang, Joseph

    2014-11-25

    Threats of chemical and biological warfare agents (CBWA) represent a serious global concern and require rapid and efficient neutralization methods. We present a highly effective micromotor strategy for photocatalytic degradation of CBWA based on light-activated TiO2/Au/Mg microspheres that propel autonomously in natural water and obviate the need for external fuel, decontaminating reagent, or mechanical agitation. The activated TiO2/Au/Mg micromotors generate highly reactive oxygen species responsible for the efficient destruction of the cell membranes of the anthrax simulant Bacillus globigii spore, as well as rapid and complete in situ mineralization of the highly persistent organophosphate nerve agents into nonharmful products. The water-driven propulsion of the TiO2/Au/Mg micromotors facilitates efficient fluid transport and dispersion of the photogenerated reactive oxidative species and their interaction with the CBWA. Coupling of the photocatalytic surface of the micromotors and their autonomous water-driven propulsion thus leads to a reagent-free operation which holds a considerable promise for diverse "green" defense and environmental applications.

  18. Characterization of Radiation Fields in Biological Shields of Nuclear Power Plants for Assessing Concrete Degradation

    NASA Astrophysics Data System (ADS)

    Remec, Igor; Rosseel, Thomas M.; Field, Kevin G.; Le Pape, Yann

    2016-02-01

    Life extensions of nuclear power plants to 60 and potentially 80 years of operation have renewed interest in long-term material degradation. One material being considered is concrete, with a particular focus on radiation-induced effects. Based on the projected neutron fluence values (E > 0.1 MeV) in the concrete biological shields of the US pressurized water reactor fleet and the available data on radiation effects on concrete, some decrease in mechanical properties of concrete cannot be ruled out during extended operation beyond 60 years. An expansion of the irradiated concrete database and a reliable determination of relevant neutron fluence energy cutoff value are necessary to ensure reliable risk assessment for extended operation of nuclear power plants. Notice: This manuscript has been authored by UT-Battelle, LLC, under contract DE-AC0500OR22725 with the US Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes.

  19. Impact of soil structure heterogeneity on the degradation of organic pollutants at the centimeter scale : 3D Modeling using graph based method

    NASA Astrophysics Data System (ADS)

    Sinclair Yemini, Francis; Chenu, Claire; Monga, Olivier; Vieuble Gonond, Laure; Juarez, Sabrina; Pihneiro, Marc; otten, Wilfred; Garnier, Patricia

    2014-05-01

    Contaminant degradation by microorganisms is very variable in soils because of the very heterogeneous spatial relationship of contaminant/degraders. Repacked Soil columns were carried out to study the degradation of 2,4D pesticide labelled with C14 for different scenarios of microorganisms and pesticide initial location. Measurements of global C14-CO2 emission and C14 distribution in the soil column showed that the initial location play a crucial rule on the dissipation of the pollutant. Experiments were simulated using a 3D model able to model microbial degradation and substrate diffusion between aggregates by considering explicitly the 3D structure of soil from CT images. The initial version of the model (Monga et al., 2008) was improved in order to simulate diffusion in samples of large size. Partial differential equations were implemented using freefem++ solver. The model simulates properly the dynamics of 2,4D in the column for the different initial situations. CT images of the same soil but using undisturbed structure instead of repacked aggregates were also carried out. Significant differences of the simulated results were observed between the repacked and the undisturbed soil. The conclusion of our work is that the heterogeneity of the soil structure and location of pollutants and decomposers has a very strong influence on the dissipation of pollutants.

  20. The influence of bacterial-humus preparations on the biological activity of soils polluted with oil products and heavy metals

    NASA Astrophysics Data System (ADS)

    Kozlova, E. N.; Stepanov, A. L.; Lysak, L. V.

    2015-04-01

    The influence of bacterial-humus preparations based on Gumigel ( Agrosintez Company) on the biological activity of soddy-podzolic soil polluted with Pb(CH3COO)2 and gasoline was studied in a model experiment. Some indicators of biological activity are shown to depend on soil pollution to different extents. The process of nitrogen fixation and the activity of dehydrogenase and phosphatase were mostly inhibited by Pb(CH3COO)2 and gasoline. Gasoline compared to Pb(CH3COO)2 inhibited the soil biological activity to a greater extent. The bacterial-humus preparations exerted a significant positive effect on the biological activity of the polluted soils manifested in the increase of the total number of bacteria and of the enzyme activity (1.5-5.0 times), in the intensification of nitrogen fixation and denitrification (3-8 times), as well as in the increase in the biomass of the plants grown (1.5-2.0 times). The application of bacterial suspensions of pure cultures or the microbial complex without the preparations of humic acids did not always give a positive effect.

  1. Separation and recovery of nucleic acids with improved biological activity by acid-degradable polyacrylamide gel electrophoresis.

    PubMed

    Kim, Yoon Kyung; Kwon, Young Jik

    2010-05-01

    One of the fundamental challenges in studying biomacromolecules (e.g. nucleic acids and proteins) and their complexes in a biological system is isolating them in their structurally and functionally intact forms. Electrophoresis offers convenient and efficient separation and analysis of biomacromolecules but recovery of separated biomacromolecules is a significant challenge. In this study, DNAs of various sizes were separated by electrophoresis in an acid-degradable polyacrylamide gel. Almost 100% of the nucleic acids were recovered after the identified gel bands were hydrolyzed under a mildly acidic condition and purified using anion exchange resin. Further concentration by centrifugal filtration and a second purification using ion exchange column chromatography yielded 44-84% of DNA. The second conventional (non-degradable) gel electrophoresis confirmed that the nucleic acids recovered from acid-degradable gel bands preserved their electrophoretic properties through acidic gel hydrolysis, purification, and concentration processes. The plasmid DNA recovered from acid-degradable gel transfected cells significantly more efficiently than the starting plasmid DNA (i.e. improved biological activity via acid-degradable PAGE). Separation of other types of nucleic acids such as small interfering RNA using this convenient and efficient technique was also demonstrated.

  2. A metabolomic study on the biological effects of metal pollutions in oysters Crassostrea sikamea.

    PubMed

    Ji, Chenglong; Wang, Qing; Wu, Huifeng; Tan, Qiaoguo; Wang, Wen-Xiong

    2016-01-15

    Metal pollution has become a great threat to organisms in the estuaries in South China. In the present study, the oysters Crassostrea sikamea were collected from one clean (Jiuzhen) and five metal polluted sites (Baijiao, Fugong, Gongqian, Jinshan and Songyu). The tissue metal concentrations in oysters indicated that the five metal sites were polluted by several metals, including Cr, Ni, Co, Cu, Zn, Ag, Cd and Pb with different patterns. Especially, Cu and Zn were the major contaminants in Baijiao, Fugong and Jinshan sites. The metabolic responses in oysters C. sikamea indicated that the metal pollutions in BJ, FG, JS and SY sites induced disturbances in osmotic regulation and energy metabolism via different metabolic pathways. However, the metal pollution in GQ site mainly influenced the osmotic regulation in the oysters C. sikamea. This study demonstrates that NMR-based metabolomics is useful to characterize metabolic responses induced by metal pollution.

  3. Factors influencing legacy pollutant accumulation in alpine osprey: biology, topography, or melting glaciers?

    PubMed

    Elliott, John E; Levac, Joshua; Guigueno, Mélanie F; Shaw, D Patrick; Wayland, Mark; Morrissey, Christy A; Muir, Derek C G; Elliott, Kyle H

    2012-09-04

    Persistent organic pollutants (POPs) can be transported long distances and deposited into alpine environments via cold trapping and snow scavenging processes. Here we examined biotic and abiotic factors determining contaminant variability of wildlife in alpine ecosystems. We measured POPs in eggs and plasma of an apex predator, the osprey (Pandion haliaetus) breeding in 15 mountainous watersheds across a broad latitudinal, longitudinal and altitudinal range in western Canada. After accounting for proximate biotic factors such as trophic level (δ(15)N) and carbon source (δ(13)C), variability in contaminant concentrations, including ΣDDT (sum of trichlorodiphenylethane-related compounds), toxaphene, hexachlorobenzene (HCB), total chlordane, and ΣPCBs (polychlorinated biphenyls) in osprey tissues was explained by interactions among relative size of watersheds, water bodies, elevation, and glacial input. ΣDDT in nestling plasma, for example, decreased with lake elevation, probably as a result of local past inputs from agricultural or public health usage at lower altitude sites. In contrast, toxaphene, never used as an insecticide in western Canada, increased with elevation and year-round snow and ice cover in both plasma and eggs, indicating long-range atmospheric sources as dominant for toxaphene. Lower chlorinated PCBs in plasma tended to decrease with elevation and ice cover consistent with published data and model outcomes. Temporal trends of POPs in osprey eggs are coincident with some modeled predictions of release from melting glaciers due to climate change. Currently we suggest that contaminants largely are released through annual snowpack melt and deposited in large lower elevation lakes, or some smaller lakes with poor drainage. Our study highlights the importance of understanding how biological processes integrate physical when studying the environmental chemistry of wildlife.

  4. Linkage of bioaccumulation and biological effects to changes in pollutant loads in south San Francisco Bay

    USGS Publications Warehouse

    Hornberger, M.I.; Luoma, S.N.; Cain, D.J.; Parchaso, F.; Brown, C.L.; Bouse, R.M.; Wellise, C.; Thompson, J.K.

    2000-01-01

    The developed world has invested billions of dollars in waste treatment since the 1970s; however, changes in ecological or biological responses are rarely associated with reductions in metal pollutants. Here we present a novel, 23-yr time series of environmental change from a San Francisco Bay mudflat located 1 km from the discharge of a suburban domestic sewage treatment plant. Samples of surface sediment, the bioindicator Macoma balthica, and metals loading data were used to establish links between discharge, bioaccumulation, and effects. Mean annual Ag concentrations in M. balthica were 106 ??g/g in 1978 and 3.67 ??g/g in 1998. Concentrations of Cu declined from 287 ??g/g in 1980 to a minimum of 24 ??g/g in 1991. Declining Cu bioaccumulation was strongly correlated with decreasing Cu loads from the plant between 1977 and 1998. Relationships with bioaccumulation and total annual precipitation suggested that inputs from nonpoint sources were most important in controlling Zn bioavailability during the same period. Ecoepidemiological criteria were used to associate failed gamete production in M. balthica to a metals-enriched environment. Reproduction persistently failed between the mid-1970s and mid-1980s; it recovered after metal contamination declined. Other potential environmental causes such as food availability, sediment chemistry, or seasonal salinity fluctuations were not related to the timing of the change in reproductive capability. The results establish an associative link, suggesting that it is important to further investigate the chemical interference of Cu and/or Ag with invertebrate reproduction at relatively moderate levels of environmental contamination.

  5. Degradation and behavior of natural steroid hormones in cow manure waste during biological treatments and ozone oxidation.

    PubMed

    Ermawati, Rahyani; Morimura, Shigeru; Tang, Yueqin; Liu, Kai; Kida, Kenji

    2007-01-01

    An efficient treatment process for screened cow manure waste, particularly for the degradation of natural steroid hormones, was developed. The first step in this process was a draw-and-fill process for thermophilic anaerobic digestion. After fourfold dilution with tap water, continuous feeding was performed for the aerobic treatment of the effluent from the anaerobic treatment. Batchwise ozone oxidation was then carried out for the degradation of the natural steroid hormones that remained in the effluent from the aerobic treatment. A yeast two-hybrid assay was performed to evaluate hormonal degradation. Significant reductions in the concentrations of total VFA, BOD(5), COD(Cr), TOC, TS, VSS, and natural steroid hormones were demonstrated in the effluent from the biological treatments. The removal ratios of such concentrations were 99.7%, 90%, 79%, 84%, 51%, 58%, and 99%, respectively. Although the concentrations of the remaining TOC and COD(Cr) remained constant, natural steroid hormones were completely removed by ozone oxidation.

  6. Chemical biology based on target-selective degradation of proteins and carbohydrates using light-activatable organic molecules.

    PubMed

    Toshima, Kazunobu

    2013-05-01

    Proteins and carbohydrates play crucial roles in a wide range of biological processes, including serious diseases. The development of novel and innovative methods for selective control of specific proteins and carbohydrates functions has attracted much attention in the field of chemical biology. In this account article, the development of novel chemical tools, which can degrade target proteins and carbohydrates by irradiation with a specific wavelength of light under mild conditions without any additives, is introduced. This novel class of photochemical agents promise bright prospects for finding not only molecular-targeted bioprobes for understanding of the structure-activity relationships of proteins and carbohydrates but also novel therapeutic drugs targeting proteins and carbohydrates.

  7. Efficient visible light photo-fenton-like degradation of organic pollutants using in situ surface-modified BiFeO3 as a catalyst.

    PubMed

    An, Junjian; Zhu, Lihua; Zhang, Yingying; Tang, Heqing

    2013-06-01

    The visible light photo-Fenton-like catalytic performance of BiFeO3 nanoparticles was investigated using Methyl Violet (MV), Rhodamine B (RhB) and phenol as probes. Under optimum conditions, the pseudo first-order rate constant (k) was determined to be 2.21 x 10(-2), 5.56 x 10(-2) and 2.01 x 10(-2) min(-1) for the degradation of MV (30 micromol/L), RhB (10 micromol/L) and phenol (3 mmol/L), respectively, in the BiFeO3-H2O2-visible light (Vis) system. The introduction of visible light irradiation increased the k values of MV, RhB and phenol degradation 3.47, 1.95 and 2.07 times in comparison with those in dark. Generally, the k values in the BiFeO3-H2O2-Vis system were accelerated by increasing BiFeO3 load and H2O2 concentration, but decreased with increasing initial pollutant concentration. To further enhance the degradation of pollutants at high concentrations, BiFeO3 was modified with the addition of surface modifiers. The addition of ethylenediamineteraacetic acid (EDTA, 0.4 mmol/L) increased the k value of MV degradation (60 micromol/L) from 1.01 x 10(-2) min(-1) in the BiFeO3-H2O2-Vis system to 1.30 min(-1) in the EDTA-BiFeO3-H2O2-Vis system by a factor of 128. This suggests that in situ surface modification can enable BiFeO3 nano-particles to be a promising visible light photo-Fenton-like catalyst for the degradation of organic pollutants.

  8. Compound-specific stable isotope analysis of herbicides in stream water: a combined monitoring and modeling approach to assess pollutant degradation at catchment scale

    NASA Astrophysics Data System (ADS)

    Lutz, Stefanie; Van der Velde, Ype; Elsayed, Omniea; Imfeld, Gwenael; Lefrancq, Marie; Payraudeau, Sylvain; Van Breukelen, Boris

    2014-05-01

    Compound-specific stable isotope analysis (CSIA) measures the isotopic composition of a compound, i.e. the relative abundance of light and heavy stable isotopes of an element contained in the compound (e.g. 12C and 13C). As degradation processes may induce a change in isotopic composition (i.e. isotope fractionation), CSIA allows distinguishing degradation from non-destructive processes such as dilution or sorption. CSIA can be combined with model-assisted interpretation to evaluate degradation of contaminants in the environment. Although CSIA methods have also been developed for diffuse pollutants such as pesticides and nitrate, they have not yet been continuously applied in monitoring of diffuse pollution in surface water. Results of a virtual experiment of isotope fractionation at hillslope scale have suggested that CSIA qualifies as a feasible and useful complement to concentration measurements of diffuse pollutants (Lutz et al., 2013). We now present the first continuously measured concentration and carbon CSIA data of herbicides from a 49-ha agricultural catchment (Alsace, France). Stream concentrations of two chloroacetanilide herbicides, i.e. S-metolachlor and acetochlor, were highest (65 μg/L) following an extreme rainfall event in the first month after herbicide application, and subsequently decreased to background concentration level (0.1 μg/L). This decrease was accompanied by an increase of more than 2 ‰ in carbon isotope ratios, which was also observed in surface runoff samples from a plot experiment in the study catchment. The increase of carbon isotope ratios over time indicates the occurrence of herbicide degradation during transport to the stream, and thus demonstrates the advantage of CSIA over pesticide concentration measurements only. Despite providing evidence of herbicide degradation, the field CSIA data do not allow for a comprehensive characterization of herbicide sources, fate and transport in the study catchment. Therefore, we

  9. Tailoring the degradation and biological response of a magnesium-strontium alloy for potential bone substitute application.

    PubMed

    Han, Junjie; Wan, Peng; Ge, Ye; Fan, Xinmin; Tan, Lili; Li, Jianjun; Yang, Ke

    2016-01-01

    Bone defects are very challenging in orthopedic practice. There are many practical and clinical shortcomings in the repair of the defect by using autografts, allografts or xenografts, which continue to motivate the search for better alternatives. The ideal bone grafts should provide mechanical support, fill osseous voids and enhance the bone healing. Biodegradable magnesium-strontium (Mg-Sr) alloys demonstrate good biocompatibility and osteoconductive properties, which are promising biomaterials for bone substitutes. The aim of this study was to evaluate and pair the degradation of Mg-Sr alloys for grafting with their clinical demands. The microstructure and performance of Mg-Sr alloys, in vitro degradation and biological properties including in vitro cytocompatibility and in vivo implantation were investigated. The results showed that the as-cast Mg-Sr alloy exhibited a rapid degradation rate compared with the as-extruded alloy due to the intergranular distribution of the second phase and micro-galvanic corrosion. However, the initial degradation could be tailored by the coating protection, which was proved to be cytocompatible and also suitable for bone repair observed by in vivo implantation. The integrated fracture calluses were formed and bridged the fracture gap without gas bubble accumulation, meanwhile the substitutes simultaneously degraded. In conclusion, the as-cast Mg-Sr alloy with coating is potential to be used for bone substitute alternative.

  10. Giant reed growth and effects on soil biological fertility in assisted phytoremediation of an industrial polluted soil.

    PubMed

    Fiorentino, N; Ventorino, V; Rocco, C; Cenvinzo, V; Agrelli, D; Gioia, L; Di Mola, I; Adamo, P; Pepe, O; Fagnano, M

    2017-01-01

    Phytoremediation is a cost-effective "green technology" that uses plants to improve the soil properties of polluted sites, preventing the dispersion of pollutants and reducing the mobility of potentially toxic elements (PTEs) through their adsorption and accumulation by roots or precipitation within the root zone. Being highly tolerant to pollutants and other abiotic stresses, giant reed (Arundo donax L.) is a suitable biomass crop for phytoremediation of contaminated soils. We report the results of a two-year open-air lysimeter study aimed at assessing the adaptability of giant reed to grow on industrial substrates polluted by Pb and Zn and at testing commercial humic acids from leonardite as improvers of plant performance. We evaluated giant reed potential for: 1) biomass production for energy or biomaterial recovery; 2) PTE phytoextraction and 3) soil fertility restoration. Chemical fertility was monitored by measuring soil C while soil biological fertility was estimated by quantifying the abundance of bacterial functional genes regulating nitrogen fixation (nifH) and nitrification (amoA). Giant reed above-ground growth on the polluted soils was slightly lower (-16%) than on a non-polluted soil, with a preferential storage of biomass in the rhizome acting as a survival strategy in limiting growing conditions. Humic acids improved plant stress tolerance and production levels. As aerial biomass (shoots) did not accumulate PTEs, the plant in question can be used for bioenergy or biopolymer production. In contrast, below-ground biomass (rhizomes) accumulated PTEs, and can thus be harvested and removed from soil to improve phytoremediation protocols and also used as industrial biofuel. Giant reed growth increased the abundance of N-cycling bacteria and soil C in the rhizospheric soil, as well as reduced soil Pb and Zn EDTA extractable fraction.

  11. Biological monitoring of roadside plants exposed to vehicular pollution in Jalgaon city.

    PubMed

    Wagh, N D; Shukla, Poonam V; Tambe, Sarika B; Ingle, S T

    2006-05-01

    Experiments on air and biomonitoring were conducted to evaluate pollution impact on the vegetation along the road in Jalgaon City, Maharashtra. The plantation along the roads and mainly includes neem (Aadirachta indica), peepal (Ficus religiosa), banyan (Ficus benghalensis), almond (Terminalia catapa). For biomonitoring, leaf area, total chlorophyll, plant protein were analyzed to study the impact of air pollutants. It was observed that vegetation at roadside with heavy traffic and markets was much affected by vehicular emission. Significant decrease in total chlorophyll and protein content was observed with reduced leaf area. It is concluded that plants can be used as indicators for urban air pollution, and there is need to protect the roadside plants from air pollution.

  12. Biological permeable reactive barriers coupled with electrokinetic soil flushing for the treatment of diesel-polluted clay soil.

    PubMed

    Mena, Esperanza; Ruiz, Clara; Villaseñor, José; Rodrigo, Manuel A; Cañizares, Pablo

    2015-01-01

    Removal of diesel from spiked kaolin has been studied in the laboratory using coupled electrokinetic soil flushing (EKSF) and bioremediation through an innovative biological permeable reactive barriers (Bio-PRBs) positioned between electrode wells. The results show that this technology is efficient in the removal of pollutants and allows the soil to maintain the appropriate conditions for microorganism growth in terms of pH, temperature, and nutrients. At the same time, EKSF was demonstrated to be a very interesting technology for transporting pollutants, microorganisms and nutrients, although results indicate that careful management is necessary to avoid the depletion of nutrients, which are effectively transported by electro-migration. After two weeks of operation, 30% of pollutants are removed and energy consumption is under 70 kWh m(-3). Main fluxes (electroosmosis and evaporation) and changes in the most relevant parameters (nutrients, diesel, microorganisms, surfactants, moisture conductivity and pH) during treatment and in a complete post-study analysis are studied to give a comprehensive description of the most relevant processes occurring in the soil (pollutant transport and biodegradation).

  13. Photoelectrochemical water splitting and simultaneous photoelectrocatalytic degradation of organic pollutant on highly smooth and ordered TiO{sub 2} nanotube arrays

    SciTech Connect

    Wu Hongjun; Zhang Zhonghai

    2011-12-15

    The photoelectrochemical water splitting and simultaneous photoelectrocatalytic degradation of organic pollutant were achieved on TiO{sub 2} nanotube electrodes with double purposes of environmental protection and renewable energy production under illumination of simulated solar light. The TiO{sub 2} nanotube arrays (TiO{sub 2} NTs) were fabricated by a two-step anodization method. The TiO{sub 2} NTs prepared in two-step anodization process (2-step TiO{sub 2} NTs) showed much better surface smoothness and tube orderliness than TiO{sub 2} NTs prepared in one-step anodization process (1-step TiO{sub 2} NTs). In the photoelectrochemical water splitting and simultaneous photoelectrocatalytic decomposition process, the 2-step TiO{sub 2} NTs electrode showed both highest photo-conversion efficiency of 1.25% and effective photodecomposition efficiency with existing of methylene blue (MB) as sacrificial agent and as pollutant target. Those results implied that the highly ordered nanostructures provided direct pathway and uniform electric field distribution for effective charges transfer, as well as superior capabilities of light harvesting. - Graphical Abstract: The photoelectrochemical water splitting for hydrogen generation and simultaneous photoelectrocatalytic degradation of organic pollutant (methylene blue) were achieved on TiO{sub 2} nanotube electrodes with double purposes of environmental protection and renewable energy production under illumination of simulated solar light. Highlights: Black-Right-Pointing-Pointer TiO{sub 2} nanotube arrays were fabricated by a two-step anodization method. Black-Right-Pointing-Pointer Hydrogen generation and organic pollutant degradation were achieved on TiO{sub 2} NTs. Black-Right-Pointing-Pointer Highest photoconversion efficiency of 1.25% was achieved. Black-Right-Pointing-Pointer Increasing orderliness will increase photocatalytic activity of TiO{sub 2} NTs.

  14. Degradation of refractory pollutants under solar light irradiation by a robust and self-protected ZnO/CdS/TiO2 hybrid photocatalyst.

    PubMed

    Zhang, Ai-Yong; Wang, Wei-Kang; Pei, Dan-Ni; Yu, Han-Qing

    2016-04-01

    Photocatalyst plays a vital role in the photochemical water treatment. To improve the visible-light photoactivity of TiO2 for refractory pollutant degradation, CdS/TiO2 hybrids with different nanostructures have been prepared, but usually suffer from a low photocatalytic degradation efficiency and a rapid photocorrosion. In this work, we developed a synergistic ZnO/CdS/TiO2 hybrid, which could act as a robust and self-protected photocatalyst for water purification without additional sacrificial reagents. This was attributed to the two different junction mechanisms in one single hybrid. Photons were selectively adsorbed by ZnO and CdS, then, the electrons with a low reductive activity in ZnO recombined directly with the holes with a low oxidative activity in CdS, whereas the holes with a high oxidative activity in ZnO and the electrons with a high reductive activity in CdS were captured for catalytic reaction. The superiority of the novel ZnO/CdS/TiO2 hybrid over the traditional CdS/TiO2 hybrid in both photocatalytic activity and anti-photocorrosion capacity was demonstrated in the degradation of Atrazine and Rhodamine B, two typical refractory organic pollutants, and the treatment of real textile wastewater under solar light irradiation. The developed ZnO/CdS/TiO2 hybrid exhibited an excellent potential for the degradation of refractory pollutants, and provided a new way to advance intrinsically solar-susceptible catalyst for photochemical wastewater treatment.

  15. Biological degradation of selected hydrocarbons in an old PAH/creosote contaminated soil from a gas work site.

    PubMed

    Eriksson, M; Dalhammar, G; Borg-Karlson, A K

    2000-05-01

    An old PAH/creosote contaminated soil (total approximately 300 microg PAH/g soil) from a former gas work site in Stockholm, Sweden, has been treated at 20 degrees C with the addition of various nutrients and inoculated with bacteria (isolated from the soil) to enhance the degradation of selected hydrocarbons. Microcosm studies showed that the soil consisted of two contaminant fractions: one available, easily degraded fraction and a strongly sorbed, recalcitrant one. The bioavailable fraction, monitored by headspace solid phase microextraction, contained aromatics with up to three rings, and these were degraded within 20 days down to non-detectable levels (ng PAH/g soil) by both the indigenous bacteria and the externally inoculated samples. The nutrient additives were: a minimal medium (Bushnell-Haas), nitrate, nitrite, potting soil (Anglamark, Sweden), sterile water and aeration with Bushnell-Haas medium. After 30 days treatment most of the sorbed fractions were still present in the soil. Stirring or mechanical mixing of the soil slurries had the greatest effect on degradation, indicating that the substances were too strongly sorbed for the microorganisms. When stirring the choice of nutrient seemed less important. For the non-stirred samples the addition of nitrate with the bacterial inoculum showed the best degradation, compared to the other non-stirred samples. At the end of the experiments, accumulations of metabolites/degradation products, such as 9H-fluorenone, 4-hydroxy-9H-fluorenone, 9,10-phenanthrenedione and 4H-cyclopenta[def]phenanthrenone were detected. The metabolite 4-hydroxy-9H-fluorenone increased by several orders of magnitude during the biological treatments. Microbial activity in the soil was measured by oxygen consumption and carbon dioxide production.

  16. Comprehensive biological effects of a complex field poly-metallic pollution gradient on the New Zealand mudsnail Potamopyrgus antipodarum (Gray).

    PubMed

    Gust, M; Buronfosse, T; Geffard, O; Coquery, M; Mons, R; Abbaci, K; Giamberini, L; Garric, J

    2011-01-17

    The Lot River is known to be contaminated by metals, mainly cadmium and zinc, due to a former Zn ore treatment plant in the watershed of the Riou-Mort, a tributary of the Lot River. Many studies have been performed to characterize contamination, but few have assessed its consequences on the biological responses of organisms along the gradient. We exposed adult and juvenile New Zealand freshwater mudsnails Potamopyrgus antipodarum at several sites along the gradient of metal contamination for 28 days. Biological responses were monitored at different levels: individual (survival, growth and fecundity), tissue and biochemical (energy status and vertebrate-like sex steroid levels) to better understand the toxicity mechanisms involved. Accumulation of Cd and Zn was high during exposure. Most of the biological effects observed could be linked to this contamination and were concentration-dependent. Histological lesions of the digestive gland were observed, with hypertrophy of calcium cells and vacuolization of digestive cells. Such effects are likely to explain the decrease of energy status (triglycerides and proteins), juvenile growth and adult fecundity observed at the most polluted site. However the magnitude of the fall in fecundity cannot be attributed only to these tissular effects, indicating another mode of action of Cd or possible confounding factors. Steroid accumulation in snails indicated only organic pollution. Histopathological effects proved the most sensitive endpoint to metal (Cd and Zn) contamination.

  17. Magnetic recoverable MnFe₂O₄ and MnFe₂O₄-graphene hybrid as heterogeneous catalysts of peroxymonosulfate activation for efficient degradation of aqueous organic pollutants.

    PubMed

    Yao, Yunjin; Cai, Yunmu; Lu, Fang; Wei, Fengyu; Wang, Xiaoyao; Wang, Shaobin

    2014-04-15

    Magnetic iron based materials are generally effective for many catalytic reactions and can be magnetically recovered after application, showing advantages than other metal oxides. In the present work, magnetic MnFe2O4 nanoparticle and MnFe2O4-reduced graphene oxide (rGO) hybrid were prepared and used as catalysts to activate peroxymonosulfate (PMS) to oxidatively degrade various organic pollutants in water. From a process of chemical deposition and reduction, MnFe2O4-rGO hybrids were produced with nanosized MnFe2O4 particles (ca. 13.2 nm). It was found that MnFe2O4 or MnFe2O4-rGO presented high activity in activating PMS to produce sulfate radicals for degradation of organic dyes (Methyl violet, Methyl orange, Methylene blue, Orange II and Rhodamine B) and could be separated with a magnet without any loss. The reaction kinetics, effect of different ion species CL(-),HCO3(-),CH3COO(-)and NO3(-) and Cl(-) strength, reaction temperature (25-65°C), catalytic stability, as well as degradation mechanism were comprehensively studied. The lower activation energy on MnFe2O4-rGO (25.7 kJ/mol) justify the higher chemical performance than that of MnFe2O4 (31.7 kJ/mol), suggesting that graphene plays a significant role in the enhanced degradation of dyes. More importantly, the as-prepared MnFe2O4 and MnFe2O4-rGO hybrid exhibited stable performance to remove the organic pollutants in wastewater with easy recycling and good stability by successive degradation experiments.

  18. A novel visible light-driven Ag3PO4/SBA-15 nanocomposite: Preparation and application in the photo-degradation of pollutants

    NASA Astrophysics Data System (ADS)

    Chai, Yuanyuan; Wang, Li; Ren, Jia; Dai, Wei-Lin

    2015-01-01

    A novel visible light-driven environmental-benign Ag3PO4/SBA-15 nanocomposite photo-catalyst was synthesized for the photo-degradation of pollutants. The exploration on adsorption and photo-catalysis of dye or organic pollution for the nanocomposite was carried out. The adsorption capability for Ag3PO4/SBA-15 nanocomposite increases by 3 times compared with that of the Ag3PO4 particles. The photo-catalytic activity of nanocomposite is higher than pristine Ag3PO4 nanoparticle for the degradation of RhB or MO under visible light irradiation (λ > 420 nm). The effect of Ag3PO4 loading on the catalytic performance was also studied. The results show that the optimum degradation is achieved over 20% Ag3PO4/SBA-15. Compared to pure Ag3PO4 nanoparticle, the most efficient catalyst showed 8 times higher photo-catalytic activity for the degradation of RhB. The Ag3PO4/SBA-15 catalysts were systematically characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-Vis diffuse reflectance spectroscopy (DRS), and N2-adsorption-desorption isotherms (BET). A possible mechanism scheme regarding photo-degradation enhancement induced by dye enrichments has been proposed on the Ag3PO4/SBA-15 nanocomposite. Additionally, the SBA-15 support can enhance the efficiency of separation of catalyst from the reaction mixture, implying that the Ag3PO4 loading on the SBA-15 catalyst will not result in the extra environment and health problems and reduce the cost of wastewater treatment.

  19. Northern fulmars as biological monitors of trends of plastic pollution in the eastern North Pacific.

    PubMed

    Avery-Gomm, Stephanie; O'Hara, Patrick D; Kleine, Lydia; Bowes, Victoria; Wilson, Laurie K; Barry, Karen L

    2012-09-01

    Marine plastic debris is a global issue, which highlights the need for internationally standardized methods of monitoring plastic pollution. The stomach contents of beached northern fulmar (Fulmarus glacialis) have proven a cost-effective biomonitor in Europe. However, recent information on northern fulmar plastic ingestion is lacking in the North Pacific. We quantified the stomach contents of 67 fulmars from beaches in the eastern North Pacific in 2009-2010 and found that 92.5% of fulmars had ingested an average of 36.8 pieces, or 0.385 g of plastic. Plastic ingestion in these fulmars is among the highest recorded globally. Compared to earlier studies in the North Pacific, our findings indicate an increase in plastic ingestion over the past 40 years. This study substantiates the use of northern fulmar as biomonitors of plastic pollution in the North Pacific and suggests that the high levels of plastic pollution in this region warrant further monitoring.

  20. Turritella attenuata (Kasinathan): as biological indicator of marine pollution--a trace metal analytical study.

    PubMed

    Paul, V I; Radhakrishnan, M V; Hemalatha, S

    1999-11-01

    A study to monitor marine pollution with reference to trace elements (Fe, Zn, Mn and Cu) on T. attenuata, commonly called as screw shell over a period of one year on the whole body and various organs, viz. digestive diverticula, foot, mantle and ovary was conducted from the sandy beach of Porto Novo Coast (Lat 11 degrees 29' N Long: 79 degrees 46' E) of Peninsular India using Atomic Absorption Spectrophotometer (AAS). Higher concentration of all the four trace metals analysed were recorded in the digestive diverticula, whereas lower concentration of zinc and manganese were recorded in the ovary during the monsoon period. The higher level of trace metal concentration in the monsoon period may be due to the presence of these pollutants in large amounts in water. The accumulation of selected trace metals varies in different seasons according to the extent of pollution load in the marine environment.

  1. Effects of organic pollution on biological communities of marine biofilm on hard substrata.

    PubMed

    Sanz-Lázaro, C; Fodelianakis, S; Guerrero-Meseguer, L; Marín, A; Karakassis, I

    2015-06-01

    We examined the effect of organic enrichment on diatom and bacterial assemblages of marine epilithic biofilms on two locations in the Mediterranean, one situated in Spain and the other in Greece. Total organic carbon, total organic nitrogen, stable isotopes (δ(13)C and δ(15)N) and chlorophyll a indicated significant incorporation of organic wastes, increased primary production and trophic niche modifications on the biofilms close to the organic enrichment source. In Spain, where the organic load was higher than in Greece, diatom and, to some extent, bacterial assemblages varied following the organic enrichment gradient. The taxonomic richness of diatom and bacterial communities was not influenced by organic enrichment. Classical community parameters showed consistent patterns to organic pollution in both locations, whereas community assemblages were only influenced when organic pollution was greatest. The successional patterns of these communities were similar to other epilithic communities. The modification of community assemblages induced by organic pollution may affect ecological functions.

  2. Enhanced organic pollutants degradation and electricity production simultaneously via strengthening the radicals reaction in a novel Fenton-photocatalytic fuel cell system.

    PubMed

    Zhao, Kai; Zeng, Qingyi; Bai, Jing; Li, Jinhua; Xia, Ligang; Chen, Shuai; Zhou, Baoxue

    2017-01-01

    An enhanced result in organic pollutants degradation and simultaneous electricity production has been achieved by establishing a novel Fenton-photocatalytic fuel cell (Fenton-PFC) system in which TiO2 nanotube arrays (TNA) was designed as a photoanode and ferrous ions were added. The proposed Fenton-PFC system can expand the radical reaction for organic pollutants degradation from the surface of electrodes to the whole solution system due to a continuous photoelectric Fenton reaction without continually adding any external voltage and ferrous ions. The cyclic reactions between ferrous ions (Fe(2+)/Fe(3+)) and radicals and related species (HO, HO2, O2(-) and H2O2 etc.) can be achieved at electrodes surface via a self-bias voltage yielded by the PFC. More importantly, the proposed Fenton-PFC system has hardly any sludge due to an effective radical reaction using a small amount of ferrous ions. The degradation rate of refractory organics, such as methyl orange, methylene blue, congo red and tetracycline, increased from 34.99%, 43.75%, 40.58% and 34.40% (the traditional PFC without Fe(2+)) to 97.34%, 95.36%, 93.23% and 73.80% (the Fenton-PFC within Fe(2+)) respectively after 60 min operation. Meanwhile, the electricity generation is up to 1.21-2.04 times larger than the traditional PFC. The proposed Fenton-PFC system provides a more economical and efficient way for energy recovery and wastewater treatment.

  3. Biological assessment of bisphenol A degradation in water following direct photolysis and UV advanced oxidation.

    PubMed

    Chen, Pei-Jen; Linden, Karl G; Hinton, David E; Kashiwada, Shosaku; Rosenfeldt, Erik J; Kullman, Seth W

    2006-11-01

    Endocrine disrupting compounds (EDCs) are exogenous environmental chemicals that can interfere with normal hormone function and present a potential threat to both environmental and human health. The fate, distribution and degradation of EDCs is a subject of considerable investigation. To date, several studies have demonstrated that conventional water treatment processes are ineffective for removal of most EDCs and in some instances produce multiple unknown transformation products. In this study we have investigated the use of direct photolysis with low-pressure (LP) Hg UV lamps and UV+hydrogen peroxide (H(2)O(2)) advanced oxidation process (AOP) for the degradation of a prototypic endocrine disrupter, bisphenol A (BPA), in laboratory water. Removal rates of BPA and formation of degradation products were determined by high performance liquid chromatography (HPLC) analysis. Changes in estrogenic activity were evaluated using both in vitro yeast estrogen screen (YES) and in vivo vitellogenin (VTG) assays with Japanese medaka fish (Oryzias latipes). Our results demonstrate that UV alone did not effectively degrade BPA. However, UV in combination with H(2)O(2) significantly removed BPA parent compound and aqueous estrogenic activity in vitro and in vivo. Removal rates of in vivo estrogenic activity were significantly lower than those observed in vitro, demonstrating differential sensitivities of these bioassays and that certain UV/AOP metabolites may retain estrogenic activity. Furthermore, the UV/H(2)O(2) AOP was effective for reducing larval lethality in treated BPA solutions, suggesting BPA degradation occurred and that the degradation process did not result in the production of acutely toxic intermediates.

  4. SMOG CHAMBERS: A TOOL TO EXAMINE EFFECTS OF PHOTOCHEMICALLY AGED AIR POLLUTANTS ON BIOLOGICAL SYSTEMS

    EPA Science Inventory

    Irradiative exposure chambers or 'Smog chambers' have been used at the University of North Carolina for over 30 years to study photochemically active mixtures of volatile organic compounds and their transformation products (a significant sub-set of Hazardous Air Pollutants, HAPs)...

  5. Occurrence and fate of tetracycline and degradation products in municipal biological wastewater treatment plant and transport of them in surface water.

    PubMed

    Topal, Murat; Arslan Topal, E Işıl

    2015-12-01

    The aims of this study are to investigate the fate of tetracycline (TC) and degradation products (DPs) in municipal biological wastewater treatment plant (MBWWTP) located in Elazığ City (Turkey) and to determine the occurrence and transport of TC and DPs in surface water (SW) (Kehli Stream) which the effluents of the plant discharged. The aqueous phase removal of TC, 4-epitetracycline (ETC), 4-epianhydrotetracycline (EATC), and anhydrotetracycline (ATC) in the studied treatment plant was 39.4 ± 1.9, 31.8 ± 1.5, 15.1 ± 0.7, and 16.9 ± 0.8%, respectively. According to the analyses' results of SW samples taken from downstream at every 500-m distance, TC and DPs decreased by the increase in the distance. In downstream, at 2000 m, TC, ETC, EATC, and ATC were 4.12 ± 0.20, 6.70 ± 0.33, 8.31 ± 0.41, and 3.57 ± 0.17 μg/L, respectively. As a result, antibiotic pollution in the SW that takes the effluent of MBWWTP exists.

  6. Degradation of organic pollutants in/on snow and ice by singlet molecular oxygen (¹O₂*) and an organic triplet excited state.

    PubMed

    Bower, Jonathan P; Anastasio, Cort

    2014-04-01

    Singlet molecular oxygen (¹O₂*) can be a significant sink for a variety of electron-rich pollutants in surface waters and atmospheric drops. We recently found that ¹O₂* concentrations are enhanced by up to a factor of 10(4) on illuminated ice compared to in the equivalent liquid solution, suggesting that ¹O₂* could be an important oxidant for pollutants in snow. To examine this, here we study the degradation of three model organic pollutants: furfuryl alcohol (to represent furans), tryptophan (for aromatic amino acids), and bisphenol A (for phenols). Each compound was studied in illuminated aqueous solution and ice containing Rose Bengal (RB, a sensitizer for ¹O₂*) and sodium chloride (to adjust the concentration of total solutes). The RB-mediated loss of each organic compound is enhanced on illuminated ice compared to in solution, by factors of 6400 for furfuryl alcohol, 8300 for tryptophan, and 50 for bisphenol A for ice containing 0.065 mM total solutes. Rates of loss of furfuryl alcohol and tryptophan decrease at a higher total solute concentration, in qualitative agreement with predictions from freezing-point depression. In contrast, the loss of bisphenol A on ice is independent of total solute concentration. Relative to liquid tests, the enhanced loss of tryptophan on ice during control experiments made with deoxygenated solutions and solutions in D₂O show that the triplet excited state of Rose Bengal may also contribute to loss of pollutants on ice.

  7. EFFECTS OF HABITAT DEGRADATION ON BIOLOGICAL ENDPOINTS IN THE SOUTH FORK BROAD RIVER BASIN, GEORGIA

    EPA Science Inventory

    Many of the streams of the lower Piedmont ecoregion in Georgia have been negatively impacted to some degree by habitat degradation due primarily to sedimentation. The South Fork of the Broad River watershed has been designated as sediment impacted under Section 303(d) of the Clea...

  8. Bioresources for control of environmental pollution.

    PubMed

    Sana, Barindra

    2015-01-01

    Environmental pollution is one of the biggest threats to human beings. For practical reasons it is not possible to stop most of the activities responsible for environmental pollution; rather we need to eliminate the pollutants. In addition to other existing means, biological processes can be utilized to get rid of toxic pollutants. Degradation, removal, or deactivation of pollutants by biological means is known as bioremediation. Nature itself has several weapons to deal with natural wastage and some of them are equally active for eliminating nonnatural pollutants. Several plants, microorganisms, and some lower eukaryotes utilize environmental pollutants as nutrients and some of them are very efficient for decontaminating specific types of pollutants. If exploited properly, these natural resources have enough potential to deal with most elements of environmental pollution. In addition, several artificial microbial consortia and genetically modified organisms with high bioremediation potential were developed by application of advanced scientific tools. On the other hand, natural equilibria of ecosystems are being affected by human intervention. Rapid population growth, urbanization, and industrialization are destroying ecological balances and the natural remediation ability of the Earth is being compromised. Several potential bioremediation tools are also being destroyed by biodiversity destruction of unexplored ecosystems. Pollution management by bioremediation is highly dependent on abundance, exploration, and exploitation of bioresources, and biodiversity is the key to success. Better pollution management needs the combined actions of biodiversity conservation, systematic exploration of natural resources, and their exploitation with sophisticated modern technologies.

  9. Enhanced photocatalytic activity for degrading pollutants of g-C3N4 by promoting oxygen adsorption after H3BO3 modification

    NASA Astrophysics Data System (ADS)

    Li, Chengming; Raziq, Fazal; Liu, Chong; Li, Zhijun; Sun, Liqun; Jing, Liqiang

    2015-12-01

    The g-C3N4 has been modified by a hydrothermal post treatment with orthoboric acid. It is shown that the surface modification with an appropriate amount of orthoboric acid obviously enhances the surface photovoltage responses of g-C3N4, clearly indicating that the separation of photogenerated charges is greatly improved. This is well responsible for the enhanced photocatalytic activities for degrading representative gas-phase acetaldehyde, and liquid-phase phenol. Moreover, it is demonstrated that the amount of O2 adsorbed on the surfaces of g-C3N4 is greatly increased after H3BO3 modification based on the O2 temperature-programmed desorption curves. It is suggested that the orthoboric acid modification favors O2 adsorption to promote the photogenerated electrons captured for improved photocatalytic activities. This work would provide feasible routes to further improve the photocatalytic performance of semiconductors for degrading pollutants.

  10. Enhanced visible photocatalytic activity of cotton ball like nano structured Cu doped ZnO for the degradation of organic pollutant.

    PubMed

    Thennarasu, G; Sivasamy, A

    2016-12-01

    Stringent Environmental standards followed worldwide led to the emergence of advanced oxidation process for the removal of toxic contaminants from water and wastewater. Among all semiconductor photocatalysts have great potential in the degradation of organic and inorganic pollutants into lesser harmful products under visible light irradiations. The present research work describes the synthesis of Cu doped ZnO (CuDZ) via a co-precipitation method to attain high crystallized powder confirmed by XRD analysis. The FE-SEM images showed that the CuDZ has cotton ball like morphology with a uniform size ranged from 25 to 40nm. TEM, FT-IR and UV-DRS studies of the synthesized CuDZ are also discussed in detail. The photocatalytic activity of the as prepared CuDZ catalyst was tested for the degradation of Direct Blue 71 (DB 71) dye in aqueous phase under visible light irradiation. The degree of degradation was found to be dependent on aqueous phase pH, duration of irradiation time, amount of photocatalyst, the initial dye concentration and kinetics of photodegradation. The maximum photocatytic degradation of DB 71 dye was found to be effective at pH 6.8. The optimum amount of photocatalyst was found 3gL(-1) of CuDZ for the complete degradation of DB 71 dye (0.01gL(-1)). The reusability of the photocatalyst indicates that 96% of DB 71 dye was degraded up to 3rd cycles of use. The visible photodegradation of DB 71 dye was exhibited pseudo-first-order kinetics. Chemical oxygen demand and ESI-MS studies confirmed the complete mineralization of DB 71 dye molecules.

  11. Optimization and application of TiO₂/Ti-Pt photo fuel cell (PFC) to effectively generate electricity and degrade organic pollutants simultaneously.

    PubMed

    Li, Kan; Zhang, Hongbo; Tang, Tiantian; Xu, Yunlan; Ying, Diwen; Wang, Yalin; Jia, Jinping

    2014-10-01

    A TiO2/Ti-Pt photo fuel cell (PFC) was established to generate electricity and degrade organic pollutants simultaneously. The electricity generation was optimized through investigation the influences of photoanode calcination temperature and dissolve oxygen on the resistances existing in PFC. TiO2 light quantum yield was also improved in PFC which resulted in a higher PC degradation efficiency. Two kinds of real textile wastewaters were also employed in this PFC system, 62.4% and 50.0% Coulombic efficiency were obtained for 8 h treatment. These refractory wastewaters with high salinity may become good fuels in PFC because a) TiO2 has no selectivity and can degrade nearly any organic substance, b) no more electrolyte is needed due to the high salinity, c) the energy in wastes can be recovered to generate electricity. The electricity generated by the PFC was further applied on a TiO2/Ti rotating disk photoelectrocatalytic reactor. A bias voltage between 0.6 and 0.75 V could be applied and the PC degradation efficiency was significantly improved. This result was similar with that obtained by a 0.7 V DC power.

  12. Establishment of Bacterial Herbicide Degraders in a Rapid Sand Filter for Bioremediation of Phenoxypropionate-Polluted Groundwater

    PubMed Central

    Feld, Louise; Nielsen, Tue Kjærgaard; Hansen, Lars Hestbjerg; Aamand, Jens

    2015-01-01

    In this study, we investigated the establishment of natural bacterial degraders in a sand filter treating groundwater contaminated with the phenoxypropionate herbicides (RS)-2-(4-chloro-2-methylphenoxy)propanoic acid (MCPP) and (RS)-2-(2,4-dichlorophenoxy)propanoic acid (DCPP) and the associated impurity/catabolite 4-chlorophenoxypropanoic acid (4-CPP). A pilot facility was set up in a contaminated landfill site. Anaerobic groundwater was pumped up and passed through an aeration basin and subsequently through a rapid sand filter, which is characterized by a short residence time of the water in the filter. For 3 months, the degradation of DCPP, MCPP, and 4-CPP in the sand filter increased to 15 to 30% of the inlet concentration. A significant selection for natural bacterial herbicide degraders also occurred in the sand filter. Using a most-probable-number (MPN) method, we found a steady increase in the number of culturable phenoxypropionate degraders, reaching approximately 5 × 105 degraders per g sand by the end of the study. Using a quantitative PCR targeting the two phenoxypropionate degradation genes, rdpA and sdpA, encoding stereospecific dioxygenases, a parallel increase was observed, but with the gene copy numbers being about 2 to 3 log units higher than the MPN. In general, the sdpA gene was more abundant than the rdpA gene, and the establishment of a significant population of bacteria harboring sdpA occurred faster than the establishment of an rdpA gene-carrying population. The identities of the specific herbicide degraders in the sand filter were assessed by Illumina MiSeq sequencing of 16S rRNA genes from sand filter samples and from selected MPN plate wells. We propose a list of potential degrader bacteria involved in herbicide degradation, including representatives belonging to the Comamonadaceae and Sphingomonadales. PMID:26590282

  13. Establishment of Bacterial Herbicide Degraders in a Rapid Sand Filter for Bioremediation of Phenoxypropionate-Polluted Groundwater.

    PubMed

    Feld, Louise; Nielsen, Tue Kjærgaard; Hansen, Lars Hestbjerg; Aamand, Jens; Albers, Christian Nyrop

    2015-11-20

    In this study, we investigated the establishment of natural bacterial degraders in a sand filter treating groundwater contaminated with the phenoxypropionate herbicides (RS)-2-(4-chloro-2-methylphenoxy)propanoic acid (MCPP) and (RS)-2-(2,4-dichlorophenoxy)propanoic acid (DCPP) and the associated impurity/catabolite 4-chlorophenoxypropanoic acid (4-CPP). A pilot facility was set up in a contaminated landfill site. Anaerobic groundwater was pumped up and passed through an aeration basin and subsequently through a rapid sand filter, which is characterized by a short residence time of the water in the filter. For 3 months, the degradation of DCPP, MCPP, and 4-CPP in the sand filter increased to 15 to 30% of the inlet concentration. A significant selection for natural bacterial herbicide degraders also occurred in the sand filter. Using a most-probable-number (MPN) method, we found a steady increase in the number of culturable phenoxypropionate degraders, reaching approximately 5 × 10(5) degraders per g sand by the end of the study. Using a quantitative PCR targeting the two phenoxypropionate degradation genes, rdpA and sdpA, encoding stereospecific dioxygenases, a parallel increase was observed, but with the gene copy numbers being about 2 to 3 log units higher than the MPN. In general, the sdpA gene was more abundant than the rdpA gene, and the establishment of a significant population of bacteria harboring sdpA occurred faster than the establishment of an rdpA gene-carrying population. The identities of the specific herbicide degraders in the sand filter were assessed by Illumina MiSeq sequencing of 16S rRNA genes from sand filter samples and from selected MPN plate wells. We propose a list of potential degrader bacteria involved in herbicide degradation, including representatives belonging to the Comamonadaceae and Sphingomonadales.

  14. Use of ERTS imagery in air pollution and marine biology studies, tasks 1 through 3

    NASA Technical Reports Server (NTRS)

    Copeland, G. E.; Ludwick, J. C.; Marshall, H. G. (Principal Investigator); Bandy, A. R.; Fleischer, P.; Hanna, W. J.; Gosink, T. A.; Bowker, D. W.

    1972-01-01

    There are no author-identified significant results in this report. The general suitability of ERTS imagery in detecting ground originated air pollution has proved to be excellent. The quality and resolution exceeded expectations and has permitted in some instances location of point sources to within a thousand feet. Suitable techniques have not yet been developed for determining or measuring area and line sources of air pollution. A major problem has been cloud cover that has persisted over the area of primary interest, the Chesapeake Bay. Work has been completed on mounting the shipboard transmissometer which will be used for investigations to relate the chlorophyll and suspended sediment content in the waters of the Lower Chesapeake Bay to ERTS-1 imagery. Water sampling, plankton analysis, and preparations for sea collection of water truth along the eastern continental shelf of the U.S. have been completed for use in comparisons with ERTS-1 data.

  15. Degradation and drug release of phosphate glass/polycaprolactone biological composites for hard-tissue regeneration.

    PubMed

    Kim, Hae-Won; Lee, Eun-Jung; Jun, In-Kook; Kim, Hyoun-Ee; Knowles, Jonathan C

    2005-10-01

    Phosphate-based glass (P-glass) and poly(epsilon-caprolactone) (PCL) composites were fabricated in a sheet form by solvent extraction and thermal pressing methods, and the antibiotic drug Vancomycin was loaded within the composites for use as a hard-tissue regenerative. The degradation and drug-release rate of the composites in vitro were tailored by modifying the glass composition: 0.45 P(2)O(5)-x CaO-(0.55-x)Na(2)O, where x=0.2, 0.3, 0.4, and 0.5. Compared to pure PCL, all the P-glass/PCL composites degraded to a higher degree, and the composite with lower-CaO glass showed a higher material loss. This was attributed mainly to the dissolution of the glass component. The glass dissolution also increased the degradation of PCL component in the composites. The Vancomycin release from the composites was strongly dependent on the glass composition. Drug release in pure PCL was initially abrupt and flattened out over a prolonged period. However, glass/PCL composites (particularly in the glass containing higher-CaO) exhibited a reduced initial burst and a higher release rate later. Preliminary cell tests on the extracts from the glass/PCL composites showed favorable cell proliferation, but the level was dependent on the ionic concentration of the extracts. The cell proliferation on the diluted extracts from the composite with higher-CaO glass was significantly higher than that on the blank culture dish. These observations confirmed that the P-glass/PCL composites are potentially applicable for use as hard-tissue regeneration and wound-healing materials because of their controlled degradation and drug-release profile as well as enhanced cell viability.

  16. Photocatalytic degradation of nitrophenol using biologically active Phyllanthus emblica seed extract.

    PubMed

    Dinesh, Murugesan; Roopan, Selvaraj Mohana; Selvaraj, Chinnadurai Immanuel

    2016-08-01

    The present study deals about the vicinity of phytochemicals present in the Phyllanthus emblica (P. emblica) seed extract. The bio-active compounds present in the methanolic seed extract have been identified using Gas Chromatography Mass Spectroscopy (GC-MS)·The antioxidant activity of P. emblica seed extract was evaluated using assistance of DPPH (2,2-Diphenyl-1-picrylhydrazyl) assay. The determination of total phenol and flavonoid substance were contemplated. Further blood clot lysis activity was also done to check the percentage of clot lysis in methanolic seed extract. The result proved that seed extract has potential application. The GCMS results of P. emblica suggest that Octyl-β-d-Glucopyranoside is present in major quantity. The work has been designed towards the degradation of 2-nitrophenol and 4-nitrophenol using P. emblica methanolic seed extract. The progress of nitrophenol degradation has been observed in UV-visible spectroscopy. At 5min duration, the 4-nitrophenol has been degraded up to 82.42%. This may be due to the presence of secondary metabolites such as alkaloids, carbohydrate and phenols in the P. emblica seed extract. The seed extract showed good scavenging activity which resulted in IC50 value of 85.92μg/mL. The total phenol and flavonoid content present in the extract were 48.242 and 12.72mg/mL. Also the seed extract showed good lysis when compared to the standard streptokinase.

  17. Interpreting biological degradative processes acting on mammalian hair in the living and the dead: which ones are taphonomic?

    PubMed

    Tridico, Silvana R; Koch, Sandra; Michaud, Amy; Thomson, Gordon; Kirkbride, K Paul; Bunce, Michael

    2014-12-07

    Although the taphonomic (post-mortem) degradation processes relevant to teeth and bones have been well described, those taking place with regards to mammalian hairs have not been characterized to the same extent. This present article describes, in detail, microscopic changes resulting from the actions of biological agents that digest and degrade hairs. The most noteworthy and prevalent agents responsible for the destruction of hair structure are fungi, which use a range of strategies to invade and digest hairs. One of the most important finds to emerge from this study is that taphonomic structures and processes can easily be interpreted by the unwary as 'real', or as class characteristics for a particular animal taxon. Moreover, under certain conditions, 'taphonomic' processes normally associated with the dead are also present on the hairs of the living. This work will improve the reliability of hair examinations in forensic, archaeological and palaeontological applications-in addition, the finding has relevance in the protection of mammalian collections susceptible to infestation. This article also addresses the popular myth that ancient peoples were often red-haired and discusses phenomena responsible for this observation. Insights gained from detailed characterization of taphonomic processes in 95 hairs from a variety of species demonstrate the range and breadth of degradative effects on hair structure and colour. Lastly, the study demonstrates that hairs often tell a story and that there is value of extracting as much morphological data as possible from hairs, prior to destructive sampling for biomolecules.

  18. Interpreting biological degradative processes acting on mammalian hair in the living and the dead: which ones are taphonomic?

    PubMed Central

    Tridico, Silvana R.; Koch, Sandra; Michaud, Amy; Thomson, Gordon; Kirkbride, K. Paul; Bunce, Michael

    2014-01-01

    Although the taphonomic (post-mortem) degradation processes relevant to teeth and bones have been well described, those taking place with regards to mammalian hairs have not been characterized to the same extent. This present article describes, in detail, microscopic changes resulting from the actions of biological agents that digest and degrade hairs. The most noteworthy and prevalent agents responsible for the destruction of hair structure are fungi, which use a range of strategies to invade and digest hairs. One of the most important finds to emerge from this study is that taphonomic structures and processes can easily be interpreted by the unwary as ‘real’, or as class characteristics for a particular animal taxon. Moreover, under certain conditions, ‘taphonomic’ processes normally associated with the dead are also present on the hairs of the living. This work will improve the reliability of hair examinations in forensic, archaeological and palaeontological applications—in addition, the finding has relevance in the protection of mammalian collections susceptible to infestation. This article also addresses the popular myth that ancient peoples were often red-haired and discusses phenomena responsible for this observation. Insights gained from detailed characterization of taphonomic processes in 95 hairs from a variety of species demonstrate the range and breadth of degradative effects on hair structure and colour. Lastly, the study demonstrates that hairs often tell a story and that there is value of extracting as much morphological data as possible from hairs, prior to destructive sampling for biomolecules. PMID:25339725

  19. Draft Genome Sequence of Nocardioides luteus Strain BAFB, an Alkane-Degrading Bacterium Isolated from JP-7-Polluted Soil

    PubMed Central

    Brown, Lisa M.; Gunasekera, Thusitha S.

    2017-01-01

    ABSTRACT Nocardioides luteus strain BAFB is a Gram-positive bacterium that efficiently degrades C8 to C11 alkanes aerobically. The draft genome of N. luteus BAFB is 5.76 Mb in size, with 5,358 coding sequences and 69.9% G+C content. The genes responsible for alkane degradation are present in this strain. PMID:28126947

  20. Metaproteomics and metabolomics analyses of chronically petroleum‐polluted sites reveal the importance of general anaerobic processes uncoupled with degradation

    PubMed Central

    Bargiela, Rafael; Herbst, Florian‐Alexander; Martínez‐Martínez, Mónica; Seifert, Jana; Rojo, David; Cappello, Simone; Genovese, María; Crisafi, Francesca; Denaro, Renata; Chernikova, Tatyana N.; Barbas, Coral; von Bergen, Martin; Yakimov, Michail M.; Golyshin, Peter N.

    2015-01-01

    Crude oil is one of the most important natural assets for humankind, yet it is a major environmental pollutant, notably in marine environments. One of the largest crude oil polluted areas in the word is the semi‐enclosed Mediterranean Sea, in which the metabolic potential of indigenous microbial populations towards the large‐scale chronic pollution is yet to be defined, particularly in anaerobic and micro‐aerophilic sites. Here, we provide an insight into the microbial metabolism in sediments from three chronically polluted marine sites along the coastline of Italy: the Priolo oil terminal/refinery site (near Siracuse, Sicily), harbour of Messina (Sicily) and shipwreck of MT Haven (near Genoa). Using shotgun metaproteomics and community metabolomics approaches, the presence of 651 microbial proteins and 4776 metabolite mass features have been detected in these three environments, revealing a high metabolic heterogeneity between the investigated sites. The proteomes displayed the prevalence of anaerobic metabolisms that were not directly related with petroleum biodegradation, indicating that in the absence of oxygen, biodegradation is significantly suppressed. This suppression was also suggested by examining the metabolome patterns. The proteome analysis further highlighted the metabolic coupling between methylotrophs and sulphate reducers in oxygen‐depleted petroleum‐polluted sediments. PMID:26201687

  1. Analysis of the microbial gene landscape and transcriptome for aromatic pollutants and alkane degradation using a novel internally calibrated microarray system.

    PubMed

    Vilchez-Vargas, Ramiro; Geffers, Robert; Suárez-Diez, María; Conte, Ianina; Waliczek, Agnes; Kaser, Vanessa Sabrina; Kralova, Monika; Junca, Howard; Pieper, Dietmar H

    2013-04-01

    Despite various efforts to develop tools to detect and compare the catabolic potential and activity for pollutant degradation in environmental samples, there is still a need for an open-source, curated and reliable array method. We developed a custom array system including a novel normalization strategy that can be applied to any microarray design, allowing the calculation of the reliability of signals and make cross-experimental comparisons. Array probes, which are fully available to the scientific community, were designed from knowledge-based curated databases for key aromatic catabolic gene families and key alkane degradation genes. This design assigns signals to the respective protein subfamilies, thus directly inferring function and substrate specificity. Experimental procedures were optimized using DNA of four genome sequenced biodegradation strains and reliability of signals assessed through a novel normalization procedure, where a plasmid containing four artificial targets in increased copy numbers and co-amplified with the environmental DNA served as an internal calibration curve. The array system was applied to assess the catabolic gene landscape and transcriptome of aromatic contaminated environmental samples, confirming the abundance of catabolic gene subfamilies previously detected by functional metagenomics but also revealing the presence of previously undetected catabolic groups and specifically their expression under pollutant stress.

  2. Control of biologically active degradation zones by vertical heterogeneity: Applications in fractured media. 1998 annual progress report

    SciTech Connect

    Colwell, F.S.; Smith, R.; McKinley, J.P.; Fredrickson, J.K.; Onstott, T.C.; Reysenbach, A.L.

    1998-06-01

    'The objective of this research is to determine the relationship between biologically active contaminant degradation zones in a fractured, subsurface medium and vertical geological heterogeneities. The research is being performed on samples collected from the Test Area North (TAN) site at the Idaho National Engineering and Environmental Laboratory (INEEL) where a dissolved trichloroethylene (TCE) plume is migrating in the basalts and interbed sediments of the Eastern Snake River Plain (ESRP) aquifer. Results are leading to an enhanced understanding of the constraints placed on the activities and distribution of TCE-degrading organisms by the geochemical and hydrological environment. This understanding allows better decisions to be made regarding the use of remedial technologies such as natural attenuation and in-situ bioremediation at geologically complex waste sites. Through this research, investigations conducted by the DOE Subsurface Science Program at TAN have been extended in order to develop a mechanistic understanding of the coupled geomicrobial and hydrogeochemical processes that are necessary to predict field-scale intrinsic degradation rates of TCE. The research objective is being accomplished by characterizing paired cores and water samples from boreholes located in differing geochemical and flow environments within the plume. Analysis of these samples will allow the determination of the spatial correlation between microbial degradation and preferred flow paths for the contaminant and required electron donors and acceptors. A combination of traditional microbiological methods (e.g., enrichments) and molecular tools are being used to characterize the indigenous microbial communities. This report summarizes work conducted after 1.5 years of a three year project.'

  3. On the Heat Stability of Amyloid-Based Biological Activity: Insights from Thermal Degradation of Insulin Fibrils

    PubMed Central

    Surmacz-Chwedoruk, Weronika; Malka, Iwona; Bożycki, Łukasz; Nieznańska, Hanna; Dzwolak, Wojciech

    2014-01-01

    Formation of amyloid fibrils in vivo has been linked to disorders such as Alzheimer’s disease and prion-associated transmissible spongiform encephalopathies. One of the characteristic features of amyloid fibrils is the high thermodynamic stability relative both to native and disordered states which is also thought to underlie the perplexingly remarkable heat resistance of prion infectivity. Here, we are comparing high-temperature degradation of native and fibrillar forms of human insulin. Decomposition of insulin amyloid has been studied under helium atmosphere and in the temperature range from ambient conditions to 750°C using thermogravimetry and differential scanning calorimetry coupled to mass spectrometry. While converting native insulin into amyloid does upshift onset of thermal decomposition by ca. 75°C, fibrils remain vulnerable to covalent degradation at temperatures below 300°C, as reflected by mass spectra of gases released upon heating of amyloid samples, as well as morphology and infrared spectra of fibrils subjected to incubation at 250°C. Mass spectra profiles of released gases indicate that degradation of fibrils is much more cooperative than degradation of native insulin. The data show no evidence of water of crystallization trapped within insulin fibrils. We have also compared untreated and heated amyloid samples in terms of capacity to seed daughter fibrils. Kinetic traces of seed-induced insulin fibrillation have shown that the seeding potency of amyloid samples decreases significantly already after exposure to 200°C, even though corresponding electron micrographs indicated persisting fibrillar morphology. Our results suggest that amyloid-based biological activity may not survive extremely high temperature treatments, at least in the absence of other stabilizing factors. PMID:24466022

  4. In vitro germination characteristics of maize pollen to detect biological activity of environmental pollutants

    SciTech Connect

    Pfahler, P.L.

    1981-01-01

    In vitro pollen germination in maize was evaluated as a method of assessing the mutagenic and physiological effects of environmental pollutants on higher organisms. The extent of mutations was effectively determined by testing sporophytes homozygous for the mutated allele. Physiological effects were effectively determined when chemical agents were added directly into the in vitro medium. Exposure of pollen grains during in vitro germination to ultraviolet radiation in the range 280-320 nm produced little or no change in the germination or rupture percentage but a sharp decrease in pollen tube growth after 1 hr.

  5. Impact of hydrodynamics on pollutant degradation and energy efficiency of VUV/UV and H2O2/UV oxidation processes.

    PubMed

    Bagheri, Mehdi; Mohseni, Madjid

    2015-12-01

    The Vacuum-UV/UV process, an incipient catalyst/chemical-free advanced oxidation process (AOP), is potentially a cost-effective solution for the removal of harmful micropollutants from water. Utilizing a novel mechanistic numerical model, this work aimed to establish a thorough understanding of the degradation mechanisms in the VUV/UV process operating under continuous flow conditions, when compared with the widely applied H2O2/UV AOP. Of particular interest was the examination of the impact of flow characteristics (hydrodynamics) on the degradation efficacy of a target micropollutant during the VUV/UV and H2O2/UV AOPs. While hydroxyl radical (OH) oxidation was the dominant degradation pathway in both processes, the degradation efficacy of the VUV/UV process showed much stronger correlation with the extent of mixing in the photoreactor. Under a uniform flow regime, the degradation efficiency of the target pollutant achieved by the H2O2/UV process with 2- and 5 ppm H2O2 was greater than that provided by the VUV/UV process. Nonetheless, introduction of mixing and circulation zones to the VUV/UV reactor resulted in superior performance compared with the H2O2/UV AOP. Based on the electrical energy-per-order (EEO) analysis, incorporation of circulation zones resulted in a reduction of up to 50% in the overall energy cost of the VUV/UV AOP, while the corresponding reduction for the 5-ppm H2O2/UV system was less than 5%. Furthermore, the extent of OH scavenging of natural organic matter (NOM) on energy efficiency of the VUV/UV and H2O2/UV AOPs under continuous flow conditions was assessed using the EEO analysis.

  6. Luciferase protection against proteolytic degradation: a key for improving signal in nano-system biology.

    PubMed

    Ataei, Farangis; Hosseinkhani, Saman; Khajeh, Khosro

    2009-10-26

    Luciferase is most widely used bioluminescence protein in biotechnological processes, but the enzyme is susceptible to proteolytic degradation, thereby its intracellular half-life decreased. Osmolytes are known to enhance the stability of proteins and protect them in a native folded and functional state. The effects of osmolytes, including sucrose, glycine and DMSO on the stability of luciferase were investigated. To different extents, all osmolytes protected the luciferase towards proteolytic degradation in a concentration-dependent manner. The results showed that 1.5M sucrose, 1.5M glycine and 15% DMSO are the best. The ability of these osmolytes to protect luciferase against proteolysis decreased from sucrose, glycine, and finally DMSO. Enzymatic kinetic data showed that the luciferase activity is significantly kept in the presence of sucrose and glycine compared to DMSO, particularly at high temperatures. Bioluminescence intensity, circular dichroism (CD), intrinsic and ANS fluorescence experiments showed change in secondary and tertiary luciferase structure. These results suggest that osmolytes exert an important effect on stabilization of luciferase conformation; decreasing the unfolding rate, preventing adaptation and binding of luciferase at the active site of proteases, thereby the proteolytic digestion reduced and its active conformation was kept.

  7. Enhancing the biological activity of chitosan and controlling the degradation by nanoscale interaction with bioglass.

    PubMed

    Ravarian, Roya; Craft, Michaela; Dehghani, Fariba

    2015-09-01

    A nonuniform degradation of physical mixture of organic-inorganic biomaterials increases their risk of failure. In this study a chemical bonding between chitosan and bioglass was used as an alternative product to address this issue. To prepare a homogenous composite, chitosan was functionalized with γ-glycidoxypropyl trimethoxysilane and chemically bonded with bioglass during sol-gel method. The gelation time of these hybrids samples was optimized by varying parameters such as composition of chitosan and temperature. It was shown that gelation time was reduced from 7 days for pure bioglass at 25°C to less than six minutes at 70°C for chitosan 40 vol % bioglass hybrid. Furthermore, the enzymatic degradation after 4 weeks was decreased from 80% mass loss for pure chitosan to 32% for chitosan 40 vol % bioglass hybrid. The results of in vitro study demonstrated that the presence of nanoscale interaction enhanced the bioactivity of chitosan. Additionally, hybrid scaffolds were fabricated with pore sizes in the range of 200-400 µm. These scaffolds were prepared by the addition of sodium bicarbonate during sol-gel method as a gas foaming agent and a neutralizer that resulted in decreasing the gelation time of hybrids to less than three minutes. The hybrids fabricated in this study possessed superior characteristics compared to chitosan, also physical mixture of chitosan-bioglass and are promising alternatives for bone tissue engineering applications.

  8. [Effects of dissolved oxygen in the oxic parts of A/O reactor on degradation of organic pollutants and analysis of microbial community for treating petrochemical wastewater].

    PubMed

    Ding, Peng-Yuan; Chu, Li-Bing; Zhang, Nan; Wang, Xing; Wang, Jian-Long

    2015-02-01

    Effects of dissolved oxygen (DO) on the biodegradation of organic pollutants were investigated using A/O reactors for the treatment of actual petrochemical wastewater. Two A/O reactors, DO were controlled at 2-3 mg x L(-1) in the oxic parts of reactor A and 5-6 mg x L(-1) of reactor B, were operated in parallel for comparison. The nearly a half of year operation results showed that the effluent COD in reactor A (72.5 ± 14.8 mg x L(-1)) was slightly higher than that in reactor B (68.7 ± 14.6 mg x L(-1)) at a HRT of 20 h. The average COD removal efficiencies were 67.0% and 68.8%, respectively. The effluent ammonium concentration was maintained at 0.8 mg x L(-1) and approximately 95% of ammonium removal was achieved. The effluent BOD, concentration was lower than 5 mg x L(-1). This indicated that the organic pollutants could be degraded thoroughly by the A/O processes, which were affected slightly by DO. Results of 454 pyrosequencing analysis of the sludge in oxic parts showed that at the phylum levels, sequences belonged to Proteobacteria, Planctomycetes and Bacteroidetes were abundant with 58.7% and 59.2%, 14.7% and 12.7%, 10.8% and 12.4% of total bacterial sequences in reactor A and B, respectively. Ammonium oxidation bacteria Nitrosomonas, nitrite oxidizing bacteria Nitrospira and obligate aerobic bacteria were highly enriched in reactor B with high DO levels, while the anaerobic denitrifiers Azospira and Acidovora were highly enriched in reactor A with low DO levels. The identified bacteria belonged to genera Novosphingobium, Comamonas, Sphingobium and Altererythrobacter were reported to degrade PAHs, chloronitrobenzene, pesticides and petroleum, which contributed to the degradation of petrochemical wastewater.

  9. Self-assembly graphitic carbon nitride quantum dots anchored on TiO2 nanotube arrays: An efficient heterojunction for pollutants degradation under solar light.

    PubMed

    Su, Jingyang; Zhu, Lin; Geng, Ping; Chen, Guohua

    2016-10-05

    In this study, an efficient heterojunction was constructed by anchoring graphitic carbon nitride quantum dots onto TiO2 nanotube arrays through hydrothermal reaction strategy. The prepared graphitic carbon nitride quantum dots, which were prepared by solid-thermal reaction and sequential dialysis process, act as a sensitizer to enhance light absorption. Furthermore, it was demonstrated that the charge transfer and separation in the formed heterojunction were significantly improved compared with pristine TiO2. The prepared heterojunction was used as a photoanode, exhibiting much improved photoelectrochemical capability and excellent photo-stability under solar light illumination. The photoelectrocatalytic activities of prepared heterojunction were demonstrated by degradation of RhB and phenol in aqueous solution. The kinetic constants of RhB and phenol degradation using prepared photoelectrode are 2.4 times and 4.9 times higher than those of pristine TiO2, respectively. Moreover, hydroxyl radicals are demonstrated to be dominant active radicals during the pollutants degradation.

  10. Carbon-dot-decorated TiO₂ nanotube arrays used for photo/voltage-induced organic pollutant degradation and the inactivation of bacteria.

    PubMed

    Feng, Lingyan; Sun, Hanjun; Ren, Jinsong; Qu, Xiaogang

    2016-03-18

    Photoluminescent carbon dots (c-dots) have recently attracted growing interest as a new member of the carbon-nanomaterial family. Here, we report for the first time that c-dot-decorated TiO2 nanotube arrays (c-dot/TiNTs) exhibit highly enhanced abilities regarding photo/voltage-induced organic pollutant degradation and bacterial inactivation. By applying UV irradiation (365 nm) or an electrochemical potential over 3 V (versus Ag/AgCl), an organic dye and a herbicide were efficiently degraded. Moreover, the inactivation of Gram-positive S. aureus and Gram-negative E. coli bacteria was realized on a c-dot/TiNT film. The c-dots were able to absorb light efficiently resulting in multiple exciton generation and also a reduction in the recombination of the e(-)/h(+) pair produced in c-dot/TiNT film during photo/voltage-induced degradation. It was also possible to readily regenerate the surface using ultraviolet light irradiation, leaving the whole film structure undamaged and with high reproducibility and stability.

  11. Carbon-dot-decorated TiO2 nanotube arrays used for photo/voltage-induced organic pollutant degradation and the inactivation of bacteria

    NASA Astrophysics Data System (ADS)

    Feng, Lingyan; Sun, Hanjun; Ren, Jinsong; Qu, Xiaogang

    2016-03-01

    Photoluminescent carbon dots (c-dots) have recently attracted growing interest as a new member of the carbon-nanomaterial family. Here, we report for the first time that c-dot-decorated TiO2 nanotube arrays (c-dot/TiNTs) exhibit highly enhanced abilities regarding photo/voltage-induced organic pollutant degradation and bacterial inactivation. By applying UV irradiation (365 nm) or an electrochemical potential over 3 V (versus Ag/AgCl), an organic dye and a herbicide were efficiently degraded. Moreover, the inactivation of Gram-positive S. aureus and Gram-negative E. coli bacteria was realized on a c-dot/TiNT film. The c-dots were able to absorb light efficiently resulting in multiple exciton generation and also a reduction in the recombination of the e-/h+ pair produced in c-dot/TiNT film during photo/voltage-induced degradation. It was also possible to readily regenerate the surface using ultraviolet light irradiation, leaving the whole film structure undamaged and with high reproducibility and stability.

  12. Activities and vectors responsible for the biological pollution in the Taranto Seas (Mediterranean Sea, southern Italy): a review.

    PubMed

    Cecere, E; Petrocelli, A; Belmonte, M; Portacci, G; Rubino, F

    2016-07-01

    Biological pollution, caused by the negative impact of alien species, also known as non-indigenous species (NIS), is regarded as one of the greatest threat to marine ecosystems. The recent upsurge in the number and spread of these species drew attention to putative vectors such as shipping and shellfish importation for culture and consumption. The port of Taranto in Southern Italy is a hub for several vectors as it serves commercial and military shipping, fishing and recreational boating, in addition to shellfish importation. An analysis of anthropogenic activities and possible vectors in Taranto Seas was recently carried out within the framework of the RITMARE Project, involving local stakeholders. Different categories of stakeholders answered dedicated questionnaires with a high degree of reticence, and this highlighted a general lack of awareness of the problems associated with alien species. Consequently, there is a strong need to instil a truly ecological awareness among the general public and stakeholders.

  13. Simultaneous determination of indoor ammonia pollution and its biological metabolite in the human body with a recyclable nanocrystalline lanthanide-functionalized MOF.

    PubMed

    Hao, Ji-Na; Yan, Bing

    2016-02-07

    A Eu(3+) post-functionalized metal-organic framework of nanosized Ga(OH)bpydc(Eu(3+)@Ga(OH)bpydc, 1a) with intense luminescence is synthesized and characterized. Luminescence measurements reveal that 1a can detect ammonia gas selectively and sensitively among various indoor air pollutants. 1a can simultaneously determine a biological ammonia metabolite (urinary urea) in the human body, which is a rare example of a luminescent sensor that can monitor pollutants in the environment and also detect their biological markers. Furthermore, 1a exhibits appealing features including high selectivity and sensitivity, fast response, simple and quick regeneration, and excellent recyclability.

  14. Evaluation of methylene diphenyl diisocyanate as an indoor air pollutant and biological assessment of methylene dianiline in the polyurethane factories.

    PubMed

    Mirmohammadi, Mirtaghi; Ibrahim, M Hakimi; Ahmad, Anees; Kadir, Mohd Omar Abdul; Mohammadyan, M; Mirashrafi, S B

    2009-04-01

    Today many raw materials used in factories may have a dangerous effect on the physiological system of workers. One of them, which is widely used in the polyurethane factories, is diisocyanates. These compounds are widely used in surface coatings, polyurethane foams, adhesives, resins, elastomers, binders, and sealants. Exposure to diisocyanates causes irritation to the skin, mucous membranes, eyes, and respiratory tract. Methylene dianiline (MDA) is a metabolite of methylene diphenyle diisocyanate (MDI), an excretory material of worker's urine who are exposed to MDI. Around 100 air samples were collected among five factories by the Midget Impinger, which contained DMSO absorbent as a solvent and Tryptamine as a reagent. Samples were analyzed by high-performance liquid chromatography with an EC\\UV detector using the NIOSH 5522 method of sampling and analysis. Also, fifty urine samples were collected from workers by using William's biological analysis method. The concentration of MDI in all air samples was more than 88 mug/m(3), showing a high concentration of the pollutant in the workplaces in comparison with the NIOSH standard, and all the worker's urine was contaminated by MDA. The correlation and regression tests were used to obtain statistical model for MDI and MDA that is useful for prediction of diisocyanates pollution situation in the polyurethane factories.

  15. Indoor air pollution evaluation with emphasize on HDI and biological assessment of HDA in the polyurethane factories.

    PubMed

    Mirmohammadi, Mirtaghi; Hakimi Ibrahim, M; Ahmad, Anees; Kadir, Mohd Omar Abdul; Mohammadyan, M; Mirashrafi, S B

    2010-06-01

    Today, many raw materials used in factories may have a dangerous effect on the physiological system of workers. One of them which is widely used in the polyurethane factories is diisocyanates. These compounds are widely used in surface coatings, polyurethane foams, adhesives, resins, elastomers, binders, and sealants. Exposure to diisocyanates causes irritation to the skin, mucous membranes, eyes, and respiratory tract. Hexamethylene diamine (HDA) is metabolite of hexamethylene diisocyanate (HDI). It is an excretory material by worker's urine who is exposed to HDI. Around 100 air samples were collected from five defined factories by midget impinger which contained dimethyl sulfoxide absorbent as a solvent and tryptamine as reagent. Samples were analyzed by high-performance liquid chromatography with EC\\UV detector using NIOSH 5522 method of sampling. Also, 50 urine samples collected from workers were also analyzed using William's biological analysis method. The concentration of HDI into all air samples were more than 88 microg/m(3), and they have shown high concentration of pollutant in the workplaces in comparison with NIOSH standard, and all of the workers' urine were contaminated by HDA. The correlation and regression test were used to obtain statistical model for HDI and HDA, which is useful for the prediction of diisocyanates pollution situation in the polyurethane factories.

  16. Breeding biology and relation of pollutants to black skimmers and gull-billed terns in South Carolina

    USGS Publications Warehouse

    Blus, Lawrence J.; Stafford, Charles J.

    1980-01-01

    The breeding biology and relation of pollutants to black skimmers (Ryn chops niger) and gull-billed terns (Gelochelidon nilotica) were investigated in South Carolina from 1969 through 1975. With few exceptions, the two species nested together in colonies located on barrier islands. We located 10 colonies, 7 of which were on the Cape Romain National Wildlife Refuge (Cape Romain); references were located that described nesting on seven other islands in South Carolina that no longer support colonies. Gull-billed terns nested from early May through July; the skimmers started later (late May) but also continued later (early September). Both species nested in areas subject to tidal flooding, and the two species persisted in nesting in several colonies despite intense predation by rats and gulls. Estimated reproductive success varied greatly from year to year and colony to colony; success in most colonies seemed low, particularly for the gull-billed tern. Residues of organochlorine pollutants in several eggs seemed of sufficient magnitude to induce adverse effects on reproductivity and eggshell thickness: however, the overall effect of organochlorines appeared negligible. Maximum numbers of nests located in a single year were 790 for the skimmer and 340 for the gull-billed tern: the total breeding population in South Carolina is unknown. Although nesting islands at Cape Romain and Deveaux Bank are sanctuaries for nesting birds, both species will continue to lose nesting habitat as additional sea islands are developed and inhabited by man.

  17. Application of Fenton's reagent as a pretreatment step in biological degradation of polyaromatic hydrocarbons

    SciTech Connect

    Kelley, R.L.; Gauger, W.K.; Srivastava, V.J.

    1990-01-01

    Fenton's reagent (H{sub 2}O{sub 2} and Fe{sup ++}) has been used for chemical oxidation of numerous organic compounds in water treatment schemes. In this study, the Institute of Gas Technology (IGT) applied Fenton's treatment to polynuclear aromatic hydrocarbons (PAHs) and PAH-contaminated soils. Fenton's treatment was very reactive with PAHs, causing rapid modification of the parental compounds to oxidized products and complete degradation to CO{sub 2}. This treatment was more effective on chemically reactive PAHs, such as benzo(a)pyrene and phenanthrene. Important parameters and conditions for Fenton's treatment of PAHs in solution and soil matrices have been identified. As much as 99% of the PAHs on soil matrices can be removed by treatment with Fenton's reagent. 28 refs., 13 figs., 1 tab.

  18. On the multiscale origins of fracture resistance in human bone and its biological degradation

    SciTech Connect

    Zimmermann, Elizabeth A.; Barth, Holly D.; Ritchie, Robert O.

    2012-03-09

    Akin to other mineralized tissues, human cortical bone can resist deformation and fracture due to the nature of its hierarchical structure, which spans the molecular to macroscopic length-scales. Deformation at the smallest scales, mainly through the composite action of the mineral and collagen, contributes to bone?s strength or intrinsic fracture resistance, while crack-tip shielding mechanisms active on the microstructural scale contribute to the extrinsic fracture resistance once cracking begins. The efficiency with which these structural features can resist fracture at both small and large length-scales becomes severely degraded with such factors as aging, irradiation and disease. Indeed aging and irradiation can cause changes to the cross-link profile at fibrillar length-scales as well as changes at the three orders of magnitude larger scale of the osteonal structures, both of which combine to inhibit the bone's overall resistance to the initiation and growth of cracks.

  19. BIODEGRADATION OF ENVIRONMENTAL POLLUTANTS BY THE WHITE ROT FUNGUS PHANEROCHAETE CHRYSOPORIUM: INVOLVEMENT OF THE LIGNIN DEGRADING SYSTEM

    EPA Science Inventory

    The white-rot fungus Phanrochaete chrysosporium has the ability to degrade a wide variety of structurally diverse organic compounds, including a number of environmentally persistent organopollutants. The unique biodegradative abilities of this fungus appears to be depend...

  20. Bioaugmentation of biological contact oxidation reactor (BCOR) with phenol-degrading bacteria for coal gasification wastewater (CGW) treatment.

    PubMed

    Fang, Fang; Han, Hongjun; Zhao, Qian; Xu, Chunyan; Zhang, Linghan

    2013-12-01

    This study was conducted to evaluate the performance of the biological contact oxidation reactor (BCOR) treating coal gasification wastewater (CGW) after augmented with phenol degrading bacteria (PDB). The PDB were isolated with phenol, 4-methyl phenol, 3,5-dimethyl phenol and resorcinol as carbon resources. Much of the refractory phenolic compounds were converted into easily-biodegradable compounds in spite of low TOC removal. The bioaugmentation with PDB significantly enhanced the removal of COD, total phenols (TP) and NH3-N, with efficiencies from 58% to 78%, 66% to 80%, and 5% to 25%, respectively. In addition, the augmented BCOR exhibited strong recovery capability in TP and COD removal while recovery of NH3-N removal needed longer time. Microbial community analysis revealed that the PDB presented as dominant populations in the bacteria consortia, which in turn determined the overall performance of the system.

  1. Control of biologically active degradation zones by vertical heterogeneity: Applications in fractured media. 1997 annual progress report

    SciTech Connect

    Colwell, F.S.; Smith, R.W.; McKinley, J.; Fredrickson, J.; Onstott, T.C.; Reysenbach, A.L.

    1997-11-01

    'The objective of this research is to determine the relationship between of biologically active contaminant degradation zones in a fractured, subsurface medium and vertical geological heterogeneities. The research is being performed on samples collected from the Test Area North (TAN) site at the Idaho National Engineering and Environmental Laboratory (INEEL) where a dissolved trichloroethylene (TCE) plume is migrating in the basalts and interbed sediments of the Eastern Snake River Plain (ESRP) aquifer. Research results are leading to an enhanced understanding of the constraints that the geochemical and hydrological environment place on the activities and distribution of TCE-degrading organisms in this fractured subsurface medium. Enhanced understanding allows better decisions to be made regarding the use of remedial technologies such as natural attenuation and in situ bioremediation at geologically complex waste sites. Through this research, investigations conducted by the Subsurface Science Program (SSP) at TAN are being extended in order to develop a mechanistic understanding of the coupled geomicrobial and hydrogeochemical processes that are necessary to predict the field-scale intrinsic degradation rates of TCE. The research objective is being accomplished by characterizing paired cores and water samples from boreholes located in differing geochemical and flow environments within the plume. Analysis of these samples will allow the determination of the spatial correlation and microbial characterization. The results presented in this report consist primarily of TAN-33 data as many of those analyses have been completed. Nearly all of the TAN-37 data has yet to be acquired. It should be noted that most of the cores were collected from zones that consist of relatively competent, massive basalt. This was because the authors were doubtful about the quality of samples obtained from rubble zones due to potential alteration by the drilling fluids. Thus, microbiological

  2. Eco-friendly and facile integrated biological-cum-photo assisted electrooxidation process for degradation of textile wastewater.

    PubMed

    Aravind, Priyadharshini; Subramanyan, Vasudevan; Ferro, Sergio; Gopalakrishnan, Rajagopal

    2016-04-15

    The present article reports an integrated treatment method viz biodegradation followed by photo-assisted electrooxidation, as a new approach, for the abatement of textile wastewater. In the first stage of the integrated treatment scheme, the chemical oxygen demand (COD) of the real textile effluent was reduced by a biodegradation process using hydrogels of cellulose-degrading Bacillus cereus. The bio-treated effluent was then subjected to the second stage of the integrated scheme viz indirect electrooxidation (InDEO) as well as photo-assisted indirect electro oxidation (P-InDEO) process using Ti/IrO2-RuO2-TiO2 and Ti as electrodes and applying a current density of 20 mA cm(-2). The influence of cellulose in InDEO has been reported here, for the first time. UV-Visible light of 280-800 nm has been irradiated toward the anode/electrolyte interface in P-InDEO. The effectiveness of this combined treatment process in textile effluent degradation has been probed by chemical oxygen demand (COD) measurements and (1)H - nuclear magnetic resonance spectroscopy (NMR). The obtained results indicate that the biological treatment allows obtaining a 93% of cellulose degradation and 47% of COD removal, increasing the efficiency of the subsequent InDEO by a 33%. In silico molecular docking analysis ascertained that cellulose fibers affect the InDEO process by interacting with the dyes that are responsible of the COD. On the other hand, P-InDEO resulted in both 95% of decolorization and 68% of COD removal, as a result of radical mediators. Free radicals generated during P-InDEO were characterized as oxychloride (OCl) by electron paramagnetic resonance spectroscopy (EPR). This form of coupled approach is especially suggested for the treatment of textile wastewater containing cellulose.

  3. Experimental Study on the Role of Sedimentation and Degradation Processes on Atmospheric Deposition of Persistent Organic Pollutants in a Subtropical Water Column.

    PubMed

    Huang, Yumei; Zhang, Ruijie; Li, Kechang; Cheng, Zhineng; Zhong, Guangcai; Zhang, Gan; Li, Jun

    2017-04-07

    The goal of this study is to experimentally assess the role of vertical sinking and degradation processes of persistent organic pollutants (POPs) in a subtropical water column. This was done by measuring the concentrations of selected typical organochlorine pesticides, including hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), dichlorodiphenyltrichloroethanes (DDTs), trans-chlordane (TC), and cis-chlordane (CC), in atmosphere (gas phase), water (dissolved and particulate phases), and sedimentation samples simultaneously from October 2011 to April 2013 in a subtropical lake. The fugacity ratios suggested net deposition for α-HCH, γ-HCH, p,p'-DDT, p,p'-DDD, p,p'-DDE, o,p'-DDT, TC, and CC, indicating that the subtropical lake was acting as a "sink" for these chemicals. The enantiomer fractions of α-HCH, o,p'-DDT, TC, and CC in the dissolved phase samples were much more deviated from the racemic values than were those in the air samples, suggesting that these chemicals have suffered microbial degradation in the subtropical lake. In fact, 99% to 100% of atmospheric input of α-HCH and γ-HCH to the subtropical lake was estimated to be depleted via microbial degradation, while the role of hydrolysis and vertical sinking was very small. For more hydrophobic p,p'-DDT, o,p'-DDT, TC, and CC, the role of vertical sinking was 2 to 3 orders of magnitude larger than that for α-HCH and γ-HCH. Microbial degradation was also very important for removing p,p'-DDT, o,p'-DDT, TC, and CC from the water column.

  4. Selecting the best AOP for isoxazolyl penicillins degradation as a function of water characteristics: Effects of pH, chemical nature of additives and pollutant concentration.

    PubMed

    Villegas-Guzman, Paola; Silva-Agredo, Javier; Florez, Oscar; Giraldo-Aguirre, Ana L; Pulgarin, Cesar; Torres-Palma, Ricardo A

    2017-04-01

    To provide new insights toward the selection of the most suitable AOP for isoxazolyl penicillins elimination, the degradation of dicloxacillin, a isoxazolyl penicillin model, was studied using different advanced oxidation processes (AOPs): ultrasound (US), photo-Fenton (UV/H2O2/Fe(2+)) and TiO2 photocatalysis (UV/TiO2). Although all processes achieved total removal of the antibiotic and antimicrobial activity, and increased the biodegradability level of the solutions, significant differences concerning the mineralization extend, the pH of the solution, the pollutant concentration and the chemical nature of additives were found. UV/TiO2 reached almost complete mineralization; while ∼10% mineralization was obtained for UV/H2O2/Fe(2+) and practically zero for US. Effect of initial pH, mineral natural water and the presence of organic (glucose, 2-propanol and oxalic acid) were then investigated. UV/H2O2/Fe(2+) and US processes were improved in acidic media, while natural pH favored UV/TiO2 system. According to both the nature of the added organic compound and the process, inhibition, no effect or enhancement of the degradation rate was observed. The degradation in natural mineral water showed contrasting results according to the antibiotic concentration: US process was enhanced at low concentration of dicloxacillin followed by detrimental effects at high substrate concentrations. A contrary effect was observed during photo-Fenton, while UV/TiO2 was inhibited in all of cases. Finally, a schema illustrating the enhancement or inhibiting effects of water matrix is proposed as a tool for selecting the best process for isoxazolyl penicillins degradation.

  5. Enhancing the biological degradability of sulfamethoxazole by ionizing radiation treatment in aqueous solution

    NASA Astrophysics Data System (ADS)

    Sági, Gyuri; Kovács, Krisztina; Bezsenyi, Anikó; Csay, Tamás; Takács, Erzsébet; Wojnárovits, László

    2016-07-01

    Changes of biodegradability and toxicity were followed up on aqueous solutions of sulfamethoxazole (SMX), during ionizing radiation treatment. The biodegradability of SMX (0.1 mmol dm-3) was specified by five-day biological oxygen demand (BOD5), using municipal activated sludge, and the results showed an improvement with applying only 0.4 kGy dose. BOD5 further increased with prolonged irradiation, indicating a conversion of SMX, a non-biodegradable compound, to biologically treatable substances. At 2.5 kGy dose, the BOD5/COD ratio increased from 0 to 0.16. The total organic carbon (TOC) content showed a decrease of only 15% at this point, thus high degree of mineralization is not necessary to make SMX digestible for the low concentrations of microorganisms used during BOD5 measurements. Increment in respiration inhibition of municipal activated sludge was observed with increasing the dose. The EC50 values showed a decrease of one order of magnitude when changing the dose from 0.4 kGy to 2.5 kGy. The increase of inhibition and formation of H2O2 showed a strong correlation.

  6. Metagenome approaches revealed a biological prospect for improvement on mesophilic cellulose degradation.

    PubMed

    Wang, Yubo; Xia, Yu; Ju, Feng; Zhang, Tong

    2015-12-01

    Improvement on the bioconversion of cellulosic biomass depends much on the expanded knowledge on the underlying microbial structure and the relevant genetic information. In this study, metagenomic analysis was applied to characterize an enriched mesophilic cellulose-converting consortium, to explore its cellulose-hydrolyzing genes, and to discern genes involved in methanogenesis. Cellulose conversion efficiency of the mesophilic consortium enriched in this study was around 70 %. Apart from methane, acetate was the major fermentation product in the liquid phase, while propionate and butyrate were also detected at relatively high concentrations. With the intention to uncover the biological factors that might shape the varying cellulose conversion efficiency at different temperatures, results of this mesophilic consortium were then compared with that of a previously reported thermophilic cellulose-converting consortium. It was found that the mesophilic consortium harbored a larger pool of putative carbohydrate-active genes, with 813 of them in 54 GH modules and 607 genes in 13 CBM modules. Methanobacteriaceae and Methanosaetaceae were the two methanogen families identified, with a preponderance of the hydrogenotrophic Methanobacteriaceae. In contrast to its relatively high diversity and high abundance of carbohydrate-active genes, the abundance of genes involved in the methane metabolism was comparatively lower in the mesophilic consortium. A biological enhancement on the methanogenic process might serve as an effective option for the improvement of the cellulose bioconversion at mesophilic temperature.

  7. Comparison of three different DNA extraction methods from a highly degraded biological material.

    PubMed

    Kuś, M; Ossowski, A; Zielińska, G

    2016-05-01

    The identification of unknown victims is one of the most challenging tasks faced by forensic medicine. This is due to the rapid decomposition of tissues, beginning at the moment of death and caused by released enzymes and microbial activity. Decay is directly associated with the decomposition of soft tissues and also the degradation of genetic material inside cells. Decomposition rates vary depending on a number of environmental factors, including temperature, humidity, season, and soil properties. Decomposition also differs between bodies left in the open air or buried. To date, forensic medicine has identified mainly people who were the victims of various types of criminal offences. However, with advances in identification methods, increasingly frequent attempts are made to identify the victims of armed conflicts, crimes of totalitarian regimes, or genocide. The aim of the study was to compare three different methods for the extraction of nuclear DNA from material considered in forensic medicine as difficult to handle, i.e. fragments of bones and teeth, and to determine the performance of these methods and their suitability for identification procedures.

  8. Secondary successions of biota in oil-polluted peat soil upon different biological remediation methods

    NASA Astrophysics Data System (ADS)

    Melekhina, E. N.; Markarova, M. Yu.; Shchemelinina, T. N.; Anchugova, E. M.; Kanev, V. A.

    2015-06-01

    The effects of different bioremediation methods on restoration of the oil-polluted peat soil (Histosol) in the northernmost taiga subzone of European Russia was studied. The population dynamics of microorganisms belonging to different trophic groups (hydrocarbon-oxidizing, ammonifying, nitrifying, and oligonitrophilic) were analyzed together with data on the soil enzyme (catalase and dehydrogenase) activities, population densities of soil microfauna groups, their structures, and states of phytocenoses during a sevenyear-long succession. The remediation with biopreparations Roder composed of oil-oxidizing microorganisms-Roder with Rhodococcus rubber and R. erythropolis and Universal with Rhodotorula glutinis and Rhodococcus sp.-was more efficient than the agrochemical and technical remediation. It was concluded that the biopreparations activate microbiological oil destruction, thereby accelerating restoration succession of phytocenosis and zoocenosis. The succession of dominant microfauna groups was observed: the dipteran larvae and Mesostigmata mites predominant at the early stages were replaced by collembolans at later stages. The pioneer oribatid mite species were Tectocepheus velatus, Oppiella nova, Liochthonius sellnicki, Oribatula tibialis, and Eupelops sp.

  9. Inhibitory Effects of Silver Nanoparticles on Removal of Organic Pollutants and Sulfate in an Anaerobic Biological Wastewater Treatment Process.

    PubMed

    Rasool, Kashif; Lee, Dae Sung

    2016-05-01

    The increasing use of silver nanoparticles (AgNPs) in commercial products and industrial processes raises issues regarding the toxicity of sludge biomass in biological wastewater treatment plants, due to potential antimicrobial properties. This study investigated the effects of AgNPs on removal of organic pollutants and sulfate in an anaerobic biological sulfate reduction process. At AgNPs concentrations of up to 10 mg/L, no significant inhibition of sulfate and COD removal was observed. However, at higher concentrations (50-200 mg/L) sulfate and COD removal efficiencies were significantly decreased to 51.8% and 33.6%, respectively. Sulfate and COD reduction followed first-order kinetics at AgNPs concentrations of up to 10 mg/L and second-order kinetics at AgNPs concentrations of 50-200 mg/L. Lactate dehydrogenase release profiles showed increases in cytotoxicity at AgNPs concentrations greater than 50 mg/L suggesting cell membrane disruption. Analysis of extracellular polymeric substances (EPS) from sulfidogenic sludge biomass and of Fourier transform infrared (FT-IR) spectra showed a decrease in concentrations of carbohydrates, proteins, humic substances, and lipids in the presence of AgNPs. Moreover, the interaction of AgNPs with sludge biomass and the damage caused to cell walls were confirmed through scanning electron microscopy with energy dispersive X-ray spectroscopy.

  10. Particulate air pollution and increased mortality: Biological plausibility for causal relationship

    SciTech Connect

    Henderson, R.F.

    1995-02-01

    Recently, a number of epidemiological studies have concluded that ambient particulate exposure is associated with increased mortality and morbidity at PM concentrations well below those previously thought to affect human health. These studies have been conducted in several different geographical locations and have involved a range of populations. While the consistency of the findings and the presence of an apparent concentration response relationship provide a strong argument for causality, epidemiological studies can only conclude this based upon inference from statistical associations. The biological plausibility of a causal relationship between low concentrations of PM and daily mortality and morbidity rates is neither intuitively obvious nor expected based on past experimental studies on the toxicity of inhaled particles. Chronic toxicity from inhaled, poorly soluble particles has been observed based on the slow accumulation of large lung burdens of particles, not on small daily fluctuations in PM levels. Acute toxicity from inhaled particles is associated mainly with acidic particles and is observed at much higher concentrations than those observed in the epidemiology studies reporting an association between PM concentrations and morbidity/mortality. To approach the difficult problem of determining if the association between PM concentrations and daily morbidity and mortality is biologically plausible and causal, one must consider (1) the chemical and physical characteristics of the particles in the inhaled atmospheres, (2) the characteristics of the morbidity/mortality observed and the people who are affected, and (3) potential mechanisms that might link the two.

  11. Anaerobic methanethiol degradation and methanogenic community analysis in an alkaline (pH 10) biological process for liquefied petroleum gas desulfurization.

    PubMed

    van Leerdam, Robin C; Bonilla-Salinas, Monica; de Bok, Frank A M; Bruning, H; Lens, Piet N L; Stams, Alfons J M; Janssen, Albert J H

    2008-11-01

    Anaerobic methanethiol (MT) degradation by mesophilic (30 degrees C) alkaliphilic (pH 10) communities was studied in a lab-scale Upflow Anaerobic Sludge Bed (UASB) reactor inoculated with a mixture of sediments from the Wadden Sea (The Netherlands), Soap Lake (Central Washington), and Russian soda lakes. MT degradation started after 32 days of incubation. During the first 252 days, complete degradation was achieved till a volumetric loading rate of 7.5 mmol MT/L/day, and sulfide, methane, and carbon dioxide were the main reaction products. Temporary inhibition of MT degradation occurred after MT peak loads and in the presence of dimethyl disulfide (DMDS), which is the autooxidation product of MT. From day 252 onwards, methanol was dosed to the reactor as co-substrate at a loading rate of 3-6 mmol/L/day to stimulate growth of methylotrophic methanogens. Methanol was completely degraded and also a complete MT degradation was achieved till a volumetric loading rate of 13 mmol MT/L/day (0.77 mmol MT/gVSS/day). However, from day 354 till the end of the experimental run (day 365), acetate was formed and MT was not completely degraded anymore, indicating that methanol-degrading homoacetogenic bacteria had partially outcompeted the methanogenic MT-degrading archea. The archeal community in the reactor sludge was analyzed by DGGE and sequencing of 16S rRNA genes. The methanogenic archea responsible for the degradation of MT in the reactor were related to Methanolobus oregonensis. A pure culture, named strain SODA, was obtained by serial dilutions in medium containing both trimethyl amine and dimethyl sulfide (DMS). Strain SODA degraded MT, DMS, trimethyl amine, and methanol. Flow sheet simulations revealed that for sufficient MT removal from liquefied petroleum gas, the extraction and biological degradation process should be operated above pH 9.

  12. Poly(L-lactide)-degrading enzyme production by Actinomadura keratinilytica T16-1 in 3 L airlift bioreactor and its degradation ability for biological recycle.

    PubMed

    Sukkhum, Sukhumaporn; Tokuyama, Shinji; Kitpreechavanich, Vichien

    2012-01-01

    The optimal physical factors affecting enzyme production in an airlift fermenter have not been studied so far. Therefore, the physical parameters such as aeration rate, pH, and temperature affecting PLA-degrading enzyme production by Actinomadura keratinilytica strain T16-1 in a 3 l airlift fermenter were investigated. The response surface methodology (RSM) was used to optimize PLA-degrading enzyme production by implementing the central composite design. The optimal conditions for higher production of PLA-degrading enzyme were aeration rate of 0.43 vvm, pH of 6.85, and temperature at 46° C. Under these conditions, the model predicted a PLA-degrading activity of 254 U/ml. Verification of the optimization showed that PLA-degrading enzyme production of 257 U/ml was observed after 3 days cultivation under the optimal conditions in a 3 l airlift fermenter. The production under the optimized condition in the airlift fermenter was higher than un-optimized condition by 1.7 folds and 12 folds with un-optimized medium or condition in shake flasks. This is the first report on the optimization of environmental conditions for improvement of PLA-degrading enzyme production in a 3 l airlift fermenter by using a statistical analysis method. Moreover, the crude PLA-degrading enzyme could be adsorbed to the substrate and degraded PLA powder to produce lactic acid as degradation products. Therefore, this incident indicates that PLA-degrading enzyme produced by Actinomadura keratinilytica NBRC 104111 strain T16-1 has a potential to degrade PLA to lactic acid as a monomer and can be used for the recycle of PLA polymer.

  13. Assessment of alginate hydrogel degradation in biological tissue using viscosity-sensitive fluorescent dyes

    NASA Astrophysics Data System (ADS)

    Shkand, Tatiana V.; Chizh, Mykola O.; Sleta, Iryna V.; Sandomirsky, Borys P.; Tatarets, Anatoliy L.; Patsenker, Leonid D.

    2016-12-01

    The main goal of this study is to investigate a combination of viscosity-sensitive and viscosity-insensitive fluorescent dyes to distinguish different rheological states of hydrogel based biostructural materials and carriers in biological tissues and to assess their corresponding location areas. The research is done in the example of alginate hydrogel stained with viscosity-sensitive dyes Seta-470 and Seta-560 as well as the viscosity-insensitive dye Seta-650. These dyes absorb/emit at 469/518, 565/591 and 651/670 nm, respectively. The rheological state of the alginate, the area of the fluorescence signal and the mass of the dense alginate versus the calcium gluconate concentration utilized for alginate gelation were studied in vitro. The most pronounced change in the fluorescence signal area was found at the same concentrations of calcium gluconate (below ~1%) as the change in the alginate plaque mass. The stained alginate was also implanted in situ in rat hip and myocardium and monitored using fluorescence imaging. In summary, our data indicate that the viscosity sensitive dye in combination with the viscosity-insensitive dye allow tracking the biodegradation of the alginate hydrogel and determining the rheological state of hydrogel in biological tissue, which both should have relevance for research and clinical applications. Using this method we estimated the half-life of the dense alginate hydrogel in a rat hip to be in the order of 4 d and about 6-8 d in rat myocardium. The half-life of the dense hydrogel in the myocardium was found to be long enough to prevent aneurysm rupture of the left ventricle wall, one of the more severe complications of the early post-infarction period.

  14. A passivated codoping approach to tailor the band edges of TiO2 for efficient photocatalytic degradation of organic pollutants

    NASA Astrophysics Data System (ADS)

    Wang, Dan; Zou, Yanhong; Wen, Shuangchun; Fan, Dianyuan

    2009-07-01

    We propose an effective passivated codoping approach to tailor the band edges of TiO2 by doping the host with group IVA and group VIB impurities to passive donor-acceptor complexes. A way of achieving p-type TiO2 is found, which can outspread the application range of TiO2 semiconductor. It is demonstrated that the carbon (C)/tungsten (W) codoped TiO2 has a substantial increase in the valence band edge, while leaving the conduction band edge almost unchanged, thus improving the efficiency of photocatalytic degradation of organic pollutants. In principle, the suggested approach for overcoming the p-type doping bottleneck can be applied to other wide-band-gap semiconductors.

  15. An integrated assessment of pollution and biological effects in flounder, mussels and sediment in the southern Baltic Sea coastal area.

    PubMed

    Dabrowska, Henryka; Kopko, Orest; Lehtonen, Kari K; Lang, Thomas; Waszak, Ilona; Balode, Maija; Strode, Evita

    2017-02-01

    Organic and metal contaminants and biological effects were investigated in flounder, mussels, and sediments in the southern Baltic Sea coastal area in order to assess environmental quality status in that area. Four sites were selected, including two within the Gulf of Gdańsk (GoG). In biota and sediment at each site, DDTs dominated over PCBs and PBDEs were the least abundant among organic contaminants. Their concentrations decreased progressively outward from GoG. Among metal contaminants, the levels of Hg, Pb, and Cd were elevated in GoG. Biomarkers in flounder, EROD activity and DNA SB, showed moderate positive correlations with organic and metal contaminants. In flounder, the integrated biomarker index (IBR/n) presented a spatial trend coherent with chemical pollution index (CPI), but there was no clear spatial correspondence between IBR/n and CPI in mussels nor between sediment toxicity index (STI) and sediment CPI. The integrated assessment of contaminant and biological effect data against available assessment criteria indicated that in biota, the contaminant assessment thresholds were most often exceeded by CB-118, heptachlor, PBDE, and Hg (in the GoG sediments by p,p'-DDT, Hg and Cd), while of the biological determinants, the threshold was breeched by AChE activity in mussels in GoG. Applying the ICES/OSPAR traffic-light approach showed that of the 50 parameters assessed at each site, there were 18% of determinants in the red color category in the two GoG sites and 8% of determinants in the two sites outside GoG, which indicated that none of the four investigated sites attained good environmental status (GES).

  16. Assessment of biological effects of environmental pollution in Mersin Bay (Turkey, northeastern Mediterranean Sea) using Mullus barbatus and Liza ramada as target organisms.

    PubMed

    Yılmaz, Doruk; Kalay, Mustafa; Dönmez, Erdem; Yılmaz, Nejat

    2016-01-01

    The increasing emphasis on the assessment and monitoring of marine ecosystems has revealed the need to use appropriate biological indicators for these areas. Enzyme activities and histopathology are increasingly being used as indicators of environmental stress since they provide a definite biological end-point of pollutant exposure. As part of an ecotoxicological assessment of Mersin Bay, EROD enzyme activity and histopathological response in selected organs and tissues of two species of fish, Mullus barbatus (red mullet) and Liza ramada (thinlip grey mullet), captured from area were examined. Pollutant (Organochlorines (OC), alkylphenols (APs) and BPA) levels and biomarker responses in tissue samples were evaluated together for their potential to alter the metabolism and cellular aspects in liver and gonad. Elevated induction of EROD activity and histopathological alterations in contaminated samples from Mersin Bay was observed compared to reference site indicating the exposure to potential pollutants.

  17. The design and realization of a large-area flexible nanofiber-based mat for pollutant degradation: an application in photocatalysis

    NASA Astrophysics Data System (ADS)

    Shang, Meng; Wang, Wenzhong; Sun, Songmei; Gao, Erping; Zhang, Zhijie; Zhang, Ling; O'Hayre, Ryan

    2013-05-01

    This work demonstrates a novel multifunctional nanofibrous mat for photocatalytic applications based on TiO2 nanocables functionalized by Ag nanoparticles and coated with a thin (~2 nm) graphitic shell. In this mat, which was realized by an electrospinning technique, each component serves a unique function: the carbon coating acts as both an adsorption material for capturing pollutants and as a charge-transfer material, the Ag nanoparticles act as a visible-light sensitizing agent and also as a charge-transfer material, finally the TiO2 nanocable mat acts as a UV sensitive photocatalytic matrix and as the flexible substrate for the other functional components. This multicomponent nanocable mat exhibits excellent photocatalytic activity under simulated solar irradiation for the degradation of model pollutants including RhB and phenol. The significant photocatalytic properties are attributed to the synergetic effect of the three functional components and the unique charge transport ``freeway'' property of the nanofibrous mat. In addition, the porous carbon coating infiltrated into the nanocable matrix endows the mat with excellent flexibility and enables robust, large-area (10 × 10 cm) fabrication, representing a significant advantage over previous brittle ceramic nanofibrous mat photocatalyst substrates. This study provides new insight into the design and preparation of an advanced, yet commercially practical and scaleable photocatalytic composite membrane material. The as-prepared photocatalytic mat might also be of interest in solar cell, catalysis, separation technology, biomedical engineering, and nanotechnology.

  18. Amendments and mulches improve the biological quality of soils degraded by mining activities in SE Spain

    NASA Astrophysics Data System (ADS)

    Luna Ramos, Lourdes; Miralles Mellado, Isabel; Hernández Fernández, María Teresa; García Izquierdo, Carlos; Solé Benet, Albert

    2014-05-01

    , which increased phosphatase activity in the compost amended soil. Plant growth was significantly higher in amended soils than in the control, but it is remarkable that the mulch type "forest chopped residue" had a negative effect on vegetation growth. The addition of organic amendments, especially compost from the organic fraction of domestic wastes, is beneficial to restore degraded or man-made soils from quarrying areas because they stimulate microbial growth and activity, resulting in mineralization of nutrients necessary for plants and increasing soil fertility and quality. However, after 5 years the effects of the mulch "forest chopped residue", on the improvement of soil or substrate quality are not clear.

  19. Preparation and characterization of Nano-graphite/TiO2 composite photoelectrode for photoelectrocatalytic degradation of hazardous pollutant.

    PubMed

    Li, Dong; Jia, Jialin; Zhang, Yuhang; Wang, Na; Guo, Xiaolei; Yu, Xiujuan

    2016-09-05

    Nano-graphite(Nano-G)/TiO2 composite photoelectrode was fabricated via sol-gel reaction, followed by the hot-press approach. The morphology, structure and light absorption capability of composite was characterized by various characterizations. The photoelectrochemical property and photoelectrocatalytic(PEC) activity of photoelectrode were also investigated. Results revealed that anatase TiO2 nanoparticles with an average diameter of 10nm were dispersed uniformly on the thickness of 2-3nm Nano-G, and TiOC bond was formed. The absorption edge of Nano-G/TiO2 photoelectrode was red-shifted towards low energy region and the enhanced visible light absorption was obtained. The charge transfer resistance of Nano-G/TiO2 photoelectrode was significantly decreased after the addition of Nano-G. And its transient photoinduced current was 10.5 times the value achieved using TiO2 electrode. Nano-G/TiO2 photoelectrode displayed greatly enhanced PEC activity of 99.2% towards the degradation of phenol, which was much higher than the 29.1% and 58.3% degradation seen on TiO2 and Nano-G electrode, respectively. The highly efficient and stable PEC activity of Nano-G/TiO2 photoelectrode was attributed to the synergy effect between photocatalysis and electrocatalysis, as well as enhanced light absorption ability and higher separation efficiency of photogenerated charge carriers. Moreover, contribution of series of reactive species to the PEC degradation of Nano-G/TiO2 photoelectrode was determined.

  20. Ag@AgHPW as a plasmonic catalyst for visible-light photocatalytic degradation of environmentally harmful organic pollutants

    SciTech Connect

    Zhou, Wenhui; Cao, Minhua Li, Na; Su, Shuangyue; Zhao, Xinyu; Wang, Jiangqiang; Li, Xianghua; Hu, Changwen

    2013-06-01

    Graphical abstract: Ag@Ag{sub x}H{sub 3−x}PW12O40 (Ag@AgHPW) nanoparticles (NPs), a new visible-light driven plasmonic photocatalyst, are prepared by a green photoreduction strategy without the addition of any surfactant, which show a high activity and stability for the degradation of methyl blue (MB) under visible light irradiation. - Highlights: • A new visible-light driven photocatalyst Ag@Ag{sub x}H{sub 3−x}PW{sub 12}O{sub 40} was designed. • The photocatalyst shows a high activity for the degradation of methyl blue. • The high activity can be ascribed to the synergy of photoexcited AgHPW and Ag. - Abstract: Ag@Ag{sub x}H{sub 3−x}PW{sub 12}O{sub 40} (Ag@AgHPW) nanoparticles (NPs), a new visible-light driven plasmonic photocatalyst, are prepared by a green photoreduction strategy without the addition of any surfactant. They show strong absorption in the visible region because of the localized surface plasmon resonance (LSPR) of Ag NPs. This plasmonic photocatalyst shows a high activity and stability for the degradation of methyl blue (MB) under visible light irradiation, which could be attributed to the highly synergy of photoexcited Ag{sub x}H{sub 3−x}PW{sub 12}O{sub 40} (AgHPW) and plasmon-excited Ag NPs and the confinement effects at interfaces between polyoxometalates (POMs) and silver. POM anions have redox ability and high photocatalytic activity, whereas Ag NPs could effectively accelerate the separation of electrons and holes, both of which contribute to their high activity.

  1. Biological degradation of tetrachloroethylene in methanogenic conditions. Final report, 12 July 1991-11 January 1993

    SciTech Connect

    Gossett, J.M.; DiStefano, T.D.; Stover, M.A.

    1994-06-01

    Research objective: investigate anaerobic biodegradation of perchloroethylene (PCE). Specific objectives: determine if the presence of PCE is necessary to sustain dechlorination of vinyl chloride (VC), delineate the role of hydrogen (H2) in PCE reductive dechlorination, investigate the ability of the high level PCE/methanol (MeOH) culture to utilize low levels of PCE, and determine the applicability of an Anaerobic Attached-film Expanded-bed (AAFEB) reactor to achieve PCE dechlorination. The investigators determined: by using a VC-fed culture unable to sustain ETH production, that the presence of PCE is required to sustain VC dechlorination, H2 acts as the electron donor directly used for the reductive dechlorination of PCE to ethene, the PCE/MeOH culture was able to use ppb levels of PCE due to the small requirement for electron donor (H2) by the culture, and that the loss of the dechlorinating biomass from the support matrix, and/or the inability of the culture to support PCE dechlorination at low concentrations, led to the failure of the AAFEB reactor system. Biodegradation, Tetrachloroethylene, Methanogenesis, Fixed-film reactors, Biological treatment, Chlorinated hydrocarbons.

  2. Fabrication of Z-scheme Ag3PO4/MoS2 composites with enhanced photocatalytic activity and stability for organic pollutant degradation

    NASA Astrophysics Data System (ADS)

    Zhu, Chaosheng; Zhang, Lu; Jiang, Bo; Zheng, Jingtang; Hu, Ping; Li, Sujuan; Wu, Mingbo; Wu, Wenting

    2016-07-01

    In this study, highly efficient visible-light-driven Ag3PO4/MoS2 composite photocatalysts with different weight ratios of MoS2 were prepared via the ethanol-water mixed solvents precipitation method and characterized by ICP, XRD, HRTEM, FE-SEM, BET, XPS, UV-vis DRS and PL analysis. Under visible-light irradiation, Ag3PO4/MoS2 composites exhibit excellent photocatalytic activity towards the degradation of organic pollutants in aqueous solution. The optimal composite with 0.648 wt% MoS2 content exhibits the highest photocatalytic activity, which can degrade almost all MB under visible-light irradiation within 60 min. Recycling experiments confirmed that the Ag3PO4/MoS2 catalysts had superior cycle performance and stability. The photocatalytic activity enhancement of Ag3PO4/MoS2 photocatalysts can be mainly ascribed to the efficient separation of photogenerated charge carriers and the stronger oxidation and reduction ability through a Z-scheme system composed of Ag3PO4, Ag and MoS2, in which Ag particles act as the charge separation center. The high photocatalytic stability is due to the successful inhibition of the photocorrosion of Ag3PO4 by transferring the photogenerated electrons of Ag3PO4 to MoS2. The evidence of the Z-scheme photocatalytic mechanism of the composite photocatalysts could be obtained from the active species trapping experiments and the photoluminescence technique.

  3. Bi-functional Au/FeS (Au/Co3O4) composite for in situ SERS monitoring and degradation of organic pollutants

    NASA Astrophysics Data System (ADS)

    Ma, Shuzhen; Cai, Qian; Lu, Kailing; Liao, Fan; Shao, Mingwang

    2016-01-01

    The bi-functional Au/FeS (Au/Co3O4) composite was fabricated by in situ reducing Au nanoparticles onto the surface of FeS (Co3O4). The as-prepared FeS possessed a multi-structure composed of plenty of nanoplates, which were coated by Au nanoparticles with an average size of 47.5 nm. While the Co3O4 showed a thin hexagonal sheet containing Au nanoparticles on its surface with an average size of 79.0 nm. Both the as-prepared Au/FeS and Au/Co3O4 composites exhibited excellent SERS performance, capable of enhancing the Raman signals of R6G molecules with the enhancement factor up to 1.81 × 106 and 7.60 × 104, respectively. Moreover, Au/FeS (Au/Co3O4) composite also has been verified to have intrinsic peroxidase-like activity, which could decompose H2O2 into hydroxyl radicals and then degrade organic pollutants into small molecules. Therefore, SERS can be used to real-time and in situ monitoring the degradation process of R6G molecules, employing the Au/FeS (Au/Co3O4) composite both as SERS substrate and catalyst.

  4. Near-Infrared- and Visible-Light-Enhanced Metal-Free Catalytic Degradation of Organic Pollutants over Carbon-Dot-Based Carbocatalysts Synthesized from Biomass.

    PubMed

    Wang, Hui; Zhuang, Jianqin; Velado, David; Wei, Zengyan; Matsui, Hiroshi; Zhou, Shuiqin

    2015-12-23

    Cost-efficient nanoparticle carbocatalysts composed of fluorescent carbon dots (CDs) embedded in carbon matrix were synthesized via one-step acid-assisted hydrothermal treatment (200 °C) of glucose. These as-synthesized CD-based carbocatalysts have excellent photoluminescence (PL) properties over a broad range of wavelengths and the external visible or NIR irradiation on the carbocatalysts could produce electrons to form electron-hole (e(-)-h(+)) pairs on the surface of carbocatalysts. These restant electron-hole pairs will react with the adsorbed oxidants/reducers on the surface of the CD-based carbocatalysts to produce active radicals for reduction of 4-nitrophenol and degradation of dye molecules. Moreover, the local temperature increase over CD-based carbocatalyst under NIR irradiation can enhance the electron transfer rate between the organic molecules and CD-based carbocatalysts, thus obviously increase the catalytic activity of the CD-based carbocatalyst for the reduction of 4-nitrophenol and the degradation of dye molecules. Such a type of CD-based carbocatalysts with excellent properties and highly efficient metal-free photocatalytic activities is an ideal candidate as photocatalysts for the reduction of organic pollutants under visible light and NIR radiation.

  5. Degradation of 2,4-dichlorophenol by combining photo-assisted Fenton reaction and biological treatment.

    PubMed

    Al Momani, F; Sans, C; Contreras, S; Esplugas, S

    2006-06-01

    The photo-Fenton reaction effect on the biodegradability improvement of 100 mg/L solution of 2,4-dichlorophenol (DCP) has been investigated. Biochemical oxygen demand (BOD) at 5 and 21 days, BODn/ chemical oxygen demand (COD) and BODn/total organic carbon (TOC) ratios, average oxidation state, and inhibition on activated sludge were monitored. For 50 mg/L hydrogen peroxide and 10 mg/L iron(II) initial concentrations and 40 minutes of reaction time in the photo-Fenton process, the biodegradability of the pretreated solution, measured as BOD5/COD ratio, was improved from 0 for the original DCP solution up to 0.18 (BOD21/COD = 0.24). At that point, all DCP was eliminated from the solution. To study the effect of the pretreatment step, the biological oxidation of pretreated solutions was tested in two semicontinuous stirred tank reactors, one operated with activated sludge and one with biomass acclimated to phenol. Results showed that more than 80% TOC removal could be obtained by codigestion of the pretreated solution with municipal wastewater. Total organic carbon removals of approximately 60% were also obtained when the sole carbon source for the aerobic reactors was the pretreated solution. The hydraulic retention times used in the bioreactors were of the same order of magnitude as those used at domestic wastewater treatment plants (i.e., between 12 and 24 hours). Kinetic studies based on pseudo-first-order kinetics have also been carried out. Constants were found to be in range 0.67 to 1.7 L x g total volatiles suspended solids(-1) x h(-1).

  6. Novel TiO2/C nanocomposites: synthesis, characterization, and application as a photocatalyst for the degradation of organic pollutants.

    PubMed

    da Costa, Elias; Zamora, Patricio P; Zarbin, Aldo J G

    2012-02-15

    Novel TiO(2)/carbon nanocomposites were prepared through the pyrolysis of TiO(2)/poly(furfuryl alcohol) hybrid materials, which were obtained by the sol-gel method, starting from titanium tetraisopropoxide (TTIP) and furfuryl alcohol (FA) precursors. Six different TiO(2)/C samples were prepared based on different TiO(2) nanoparticle sizes and TiO(2)/FA ratios. All of the samples were characterized using X-ray diffraction, infrared, and Raman spectroscopy. The results indicated effective FA polymerization onto the TiO(2) (anatase) nanoparticles, polymer conversion to disordered carbon following the pyrolysis, and a simultaneous TiO(2) anatase-rutile phase transition. The resulting TiO(2)/carbon composites were used as photocatalysts in the advanced oxidative process (AOP) for the degradation of reactive organic dyes in aqueous solution. The results indicate excellent photocatalytic performance (degradation of 99% of the dye after 60 min) with several advantages over traditional TiO(2)-based photocatalysts.

  7. Mechanistic Studies of TiO2 Photocatalysis and Fenton Degradation of Hydrophobic Aromatic Pollutants in Water.

    PubMed

    Gong, Yuanzheng; Yang, Chun; Ji, Hongwei; Chen, Chuncheng; Ma, Wanhong; Zhao, Jincai

    2016-12-19

    HO-adduct radicals have been investigated and confirmed as the common initial intermediates in TiO2 photocatalysis and Fenton degradations of water-insoluble aromatics. However, the evolution of HO-adduct radicals to phenols has not been completely clarified. When 4-d-toluene and p-xylene were degraded by TiO2 photocatalysis and Fenton reactions, respectively, a portion of the 4-deuterium or 4-CH3 group (18-100 %) at the attacked ipso position shifted to the adjacent position of the ring in the formed phenols (NIH shift; NIH is short for the National Institutes of Health, to honor the place where this phenomenon was first discovered). The results, combined with the observation of a key dienyl cationic intermediate by in situ attenuated total reflectance FTIR spectroscopy, indicate that, for the evolution of HO-adduct radicals, a mixed mechanism of both the carbocation intermediate pathway and O2 -capturing pathway occurs in both aqueous TiO2 photocatalysis and aqueous Fenton reactions.

  8. Spatial and temporal variations of biological responses to environmental pollution in the freshwater zebra mussel.

    PubMed

    Guerlet, Edwige; Vasseur, Paule; Giambérini, Laure

    2010-09-01

    The validation of a suite of cellular biomarkers for biomonitoring studies necessitates a good knowledge of the meaning of these early responses to environmental stress in terms of individual health. This requires confirmation (i) of linkages between the cellular and higher levels of the biological organisation, (ii) of temporal persistence of the stress symptoms and (iii) of their reversibility after a return to more favourable conditions. Besides, (iv) the sensitivity of the biomarker suite towards subtle variations of environmental contamination has to be assessed. With this aim, field experiments were performed on deployed freshwater zebra mussels (Dreissena polymorpha) in the vicinity of the confluence of a small heavily anthropized stream with a larger river. We examined the persistence of the responses over a 90-day period and their reversibility after a depuration-transplantation. A second experiment was conducted later by adding a study site at an increased distance from the confluence. Decreased digestive lysosomal volume and neutral lipid contents, and lipofuscin accumulation preceded effects on the mussels' condition. The following experiment confirmed that the cellular biomarkers were more sensitive than both individual endpoints to reflect the effects of subtler variations of environmental contamination. Integration of the results with multivariate analysis and the Integrated Biomarker Response tended to confirm the relevance of the biomarker suite.

  9. Migration and degradation of swine farm tetracyclines at the river catchment scale: Can the multi-pond system mitigate pollution risk to receiving rivers?

    PubMed

    Chen, Qiuwen; Guo, Xiao; Hua, Guofen; Li, Guoliang; Feng, Ranran; Liu, Xiaoli

    2017-01-01

    The study investigated the degradation behaviors of swine farm tetracyclines (TCs) at a catchment scale and explored whether multi-pond systems could be beneficial to the interception of TCs so as to reduce the pollution risk to receiving rivers. The occurrence and migration of 12 kinds of tetracycline antibiotics, including their degradation products, were studied in four swine farms of the Meijiang River basin in China. The migration paths of the TCs were examined through sampling and analyzing the soil and/or sediment at different points along the swine wastewater outlet, which included sewer, sewage pond, mixed-canal (stream and sewage), farmland (paddy and upland soil) and finally the river. TC concentrations of all collected samples were obtained by solid phase extraction followed by measurement with high-performance liquid chromatography tandem mass spectrometry. The results showed that sediment TC concentrations varied greatly in different swine farms, from mg·kg(-1) to μg·kg(-1) levels. TCs had different decay patterns along different migration paths, such that TCs decayed exponentially in paddy soil, while linearly in sewer and mixed canal. The concentrations of TCs and their degradation products decreased in the order: sewer sediment > sewage pond sediment > mixed-canal sediment > paddy soil > upland soil, indicating that TCs tend to be more easily intercepted and accumulated in water-sediment systems such as ponds. Therefore, the multi-pond system could be an effective way to prevent TCs from migrating into rivers. These results provided essential information for contamination control of antibiotics in aquatic environments.

  10. Photocatalytic degradation of an emerging pollutant by TiO2-coated glass rings: a kinetic study.

    PubMed

    Manassero, Agustina; Satuf, María Lucila; Alfano, Orlando Mario

    2016-05-24

    This work presents the photocatalytic degradation of the pharmaceutical drug clofibric acid in a fixed-bed reactor filled with TiO2-coated glass rings. Experiments were carried out under UV radiation. A kinetic model that takes into account radiation absorption by means of the local surface rate of photon absorption (LSRPA) has been developed. The LSRPA was obtained from the results of a radiation model. The Monte Carlo method was employed to solve the radiation model, where the interaction between photons and TiO2-coated rings was considered. Data from experiments carried out with rings with different numbers of catalyst coatings and different irradiation levels were used to estimate the parameters of the kinetic model. A satisfactory agreement was obtained between model simulations and experimental results.

  11. Microbial Nursery Production of High-Quality Biological Soil Crust Biomass for Restoration of Degraded Dryland Soils.

    PubMed

    Velasco Ayuso, Sergio; Giraldo Silva, Ana; Nelson, Corey; Barger, Nichole N; Garcia-Pichel, Ferran

    2017-02-01

    Biological soil crusts (biocrusts) are slow-growing, phototroph-based microbial assemblages that develop on the topsoils of drylands. Biocrusts help maintain soil fertility and reduce erosion. Because their loss through human activities has negative ecological and environmental health consequences, biocrust restoration is of interest. Active soil inoculation with biocrust microorganisms can be an important tool in this endeavor. We present a culture-independent, two-step process to grow multispecies biocrusts in open greenhouse nursery facilities, based on the inoculation of local soils with local biocrust remnants and incubation under seminatural conditions that maintain the essence of the habitat but lessen its harshness. In each of four U.S. Southwest sites, we tested and deployed combinations of factors that maximized growth (gauged as chlorophyll a content) while minimizing microbial community shifts (assessed by 16S rRNA sequencing and bioinformatics), particularly for crust-forming cyanobacteria. Generally, doubling the frequency of natural wetting events, a 60% reduction in sunlight, and inoculation by slurry were optimal. Nutrient addition effects were site specific. In 4 months, our approach yielded crusts of high inoculum quality reared on local soil exposed to locally matched climates, acclimated to desiccation, and containing communities minimally shifted in composition from local ones. Our inoculum contained abundant crust-forming cyanobacteria and no significant numbers of allochthonous phototrophs, and it was sufficient to treat ca. 6,000 m(2) of degraded dryland soils at 1 to 5% of the typical crust biomass concentration, having started from a natural crust remnant as small as 6 to 30 cm(2) IMPORTANCE: Soil surface crusts can protect dryland soils from erosion, but they are often negatively impacted by human activities. Their degradation causes a loss of fertility, increased production of fugitive dust and intensity of dust storms with associated

  12. Combined use of GIS and environmental indicators for assessment of chemical, physical and biological soil degradation in a Spanish Mediterranean region.

    PubMed

    de Paz, José-Miguel; Sánchez, Juan; Visconti, Fernando

    2006-04-01

    Soil is one of the main non-renewable natural resources in the world. In the Valencian Community (Mediterranean coast of Spain), it is especially important because agriculture and forest biomass exploitation are two of the main economic activities in the region. More than 44% of the total area is under agriculture and 52% is forested. The frequently arid or semi-arid climate with rainfall concentrated in few events, usually in the autumn and spring, scarcity of vegetation cover, and eroded and shallow soils in several areas lead to soil degradation processes. These processes, mainly water erosion and salinization, can be intense in many locations within the Valencian Community. Evaluation of soil degradation on a regional scale is important because degradation is incompatible with sustainable development. Policy makers involved in land use planning require tools to evaluate soil degradation so they can go on to develop measures aimed at protecting and conserving soils. In this study, a methodology to evaluate physical, chemical and biological soil degradation in a GIS-based approach was developed for the Valencian Community on a 1/200,000 scale. The information used in this study was obtained from two different sources: (i) a soil survey with more than 850 soil profiles sampled within the Valencian Community, and (ii) the environmental information implemented in the Geo-scientific map of the Valencian Community digitised on an Arc/Info GIS. Maps of physical, chemical and biological soil degradation in the Valencian Community on a 1/200,000 scale were obtained using the methodology devised. These maps can be used to make a cost-effective evaluation of soil degradation on a regional scale. Around 29% of the area corresponding to the Valencian Community is affected by high to very high physical soil degradation, 36% by high to very high biological degradation, and 6% by high to very high chemical degradation. It is, therefore, necessary to draw up legislation and to

  13. Comparison of biological activated carbon (BAC) and membrane bioreactor (MBR) for pollutants removal in drinking water treatment.

    PubMed

    Tian, J Y; Chen, Z L; Liang, H; Li, X; Wang, Z Z; Li, G B

    2009-01-01

    Biological activated carbon (BAC) and membrane bioreactor (MBR) were systematically compared for the drinking water treatment from slightly polluted raw water under the same hydraulic retention time (HRT) of 0.5 h. MBR exhibited excellent turbidity removal capacity due to the separation of the membrane; while only 60% of influent turbidity was intercepted by BAC. Perfect nitrification was achieved by MBR with the 89% reduction in ammonia; by contrast, BAC only eliminated a moderate amount of influent ammonia (by 54.5%). However, BAC was able to remove more dissolved organic matter (DOM, especially for organic molecules of 3,000 approximately 500 Daltons) and corresponding disinfection by-product formation potential (DBPFP) in raw water than MBR. Unfortunately, particulate organic matter (POM) was detected in the BAC effluent. On the other hand, BAC and MBR displayed essentially the same capacity for biodegradable organic matter (BOM) removal. Fractionation of DOM showed that the removal efficiencies of hydrophobic neutrals, hydrophobic acids, weakly hydrophobic acids and hydrophilic organic matter through BAC treatment were 11.7%, 8.8%, 13.9% and 4.8% higher than that through MBR; while MBR achieved 13.8% higher hydrophobic bases removal as compared with BAC.

  14. Risk assessment and toxic effects of metal pollution in two cultured and wild fish species from highly degraded aquatic habitats.

    PubMed

    Omar, Wael A; Zaghloul, Khalid H; Abdel-Khalek, Amr A; Abo-Hegab, S

    2013-11-01

    Lake Qaroun is an inland lake at the lowest part of El-Fayoum depression, Egypt. It receives agricultural and domestic non-treated drainage waters, which are also used for aquaculture in Qaroun area. The results of the present study aimed to provide comparable data between wild (collected from Lake Qaroun) and cultured (collected from Qaroun fish farms and the reference site) Nile tilapia Oreochromis niloticus and mullet Mugil cephalus, as indicators of natural and anthropogenic impacts on aquatic ecosystem as well as to evaluate the human hazard index associated with fish consumption. Metal concentrations in fish tissues showed a species-specific bioaccumulation pattern. Statistically significant differences were observed in the mean metal concentrations with lower bioavailability in M. cephalus compared with O. niloticus in internal vital organs (liver, kidney, and muscle) but much higher in external organs (gill and skin). Histopathological alterations and evident damages were observed in gill, liver, and kidney of both species collected from Lake Qaroun and Qaroun fish farms compared with those from the reference site. The results showed significant increase of plasma aspartate aminotransferase and alanine aminotransferase activity as well as creatinine and uric acid concentration in both fish species from polluted locations. The human health hazard index showed that the cumulative risk greatly increases with increasing fish consumption rate, thus yielding an alarming concern for consumer health.

  15. Degradation of synthetic pollutants in real wastewater using laccase encapsulated in core-shell magnetic copper alginate beads.

    PubMed

    Le, Thao Thanh; Murugesan, Kumarasamy; Lee, Chung-Seop; Vu, Chi Huong; Chang, Yoon-Seok; Jeon, Jong-Rok

    2016-09-01

    Immobilization of laccase has been highlighted to enhance their stability and reusability in bioremediation. In this study, we provide a novel immobilization technique that is very suitable to real wastewater treatment. A perfect core-shell system composing copper alginate for the immobilization of laccase (Lac-beads) was produced. Additionally, nFe2O3 was incorporated for the bead recycling through magnetic force. The beads were proven to immobilize 85.5% of total laccase treated and also to be structurally stable in water, acetate buffer, and real wastewater. To test the Lac-beads reactivity, triclosan (TCS) and Remazol Brilliant Blue R (RBBR) were employed. The Lac-beads showed a high percentage of TCS removal (89.6%) after 8h and RBBR decolonization at a range from 54.2% to 75.8% after 4h. Remarkably, the pollutants removal efficacy of the Lac-beads was significantly maintained in real wastewater with the bead recyclability, whereas that of the corresponding free laccase was severely deteriorated.

  16. Bifunctional-nanotemplate assisted synthesis of nanoporous SrTiO₃ photocatalysts toward efficient degradation of organic pollutant.

    PubMed

    Ouyang, Shuxin; Li, Peng; Xu, Hua; Tong, Hua; Liu, Lequan; Ye, Jinhua

    2014-12-24

    Nanoporous SrTiO3 photocatalysts were fabricated via a novel technique, the nanotemplate assisted sol-gel hydrothermal reaction. In the alkaline-environment hydrothermal reaction, the SiO2 nanotemplate not only served as pore generator but also worked on adjusting the local reaction environment around the SrTiO3 nanocrystals. This contributed to a continuous modulation between the surface area and the crystallinity of the photocatalyst. The photocatalytic activities of the nanoporous SrTiO3 samples were evaluated by the degradation of gaseous isopropyl alcohol (IPA). Due to an optimal equilibrium between surface area and crystallinity, a SrTiO3 sample synthesized via adding 40% template (STO-SiO2-40%) showed the highest activity, which achieves 40 and 8 times of enhancement of CO2 evolution in comparison with the sample prepared without template and a commercial nano-SrTiO3, respectively. The photodegradation mechanism of IPA over this sample was also investigated in detail. This synthetic technique is also available to prepare the other nanoporous titanates, such as doped SrTiO3 samples and alkali-metal titanates.

  17. Oxygen vacancies in shape controlled Cu2O/reduced graphene oxide/In2O3 hybrid for promoted photocatalytic water oxidation and degradation of environmental pollutants.

    PubMed

    Liu, Jie; Ke, Jun; Li, Degang; Sun, Hongqi; Liang, Ping; Duan, Xiaoguang; Tian, Wenjie; Tade, Moses O; Liu, Shaomin; Wang, Shaobin

    2017-03-16

    A novel shape controlled Cu2O/reduced graphene oxide/In2O3 (Cu2O/RGO/In2O3) hybrid with abundant oxygen vacancies was prepared by a facile, surfactant-free method. The hybrid photocatalyst exhibits an increased photocatalytic activity in water oxidation and degradation of environmental pollutants (methylene blue and Cr6+ solutions) compared with pure In2O3 and Cu2O materials. The presence of oxygen vacancies in Cu2O/RGO/In2O3 and the formation of heterojunction between In2O3 and Cu2O induce extra diffusive electronic states above the valence band (VB) edge and reduce the band gap of the hybrid consequently. Besides, the increased activity of Cu2O/RGO/In2O3 hybrid is also attributed to the alignment of band edge, a process that is assisted by different Fermi levels between In2O3 and Cu2O, as well as the charge transfer and distribution onto the graphene sheets, which causes the downshift of VB of In2O3 and the significant increase in its oxidation potential. Additionally, a built-in electric field is generated on the interface of n-type In2O3 and p-type Cu2O, suppressing the recombination of photo-induced electron-hole pairs and allowing the photo-generated electrons and holes to participate in the reduction and oxidation reactions for oxidizing water molecules and pollutants more efficiently.

  18. Visible Light Assisted Heterogeneous Fenton-like Degradation of Organic Pollutant via α-FeOOH/Mesoporous Carbon Composites.

    PubMed

    Qian, Xufang; Ren, Meng; Zhu, Yao; Yue, Dongting; Han, Yu; Jia, Jinping; Zhao, Yixin

    2017-03-03

    A α-FeOOH/mesoporous carbon (α-FeOOH/MesoC) composite prepared by in situ crystallization of adsorbed ferric ions within carboxyl functionalized mesoporous carbon was developed as a novel visible light assisted heterogeneous Fenton-like catalyst. The visible light active α-FeOOH nanocrystals were encapsulated in the mesoporous frameworks accompanying with surface attached large α-FeOOH microcrystals via C-O-Fe bonding. Assisting with visible light irradiation on α-FeOOH/MesoC, the mineralization efficiency increased owing to the photocatalytic promoted catalyzing H2O2 beyond the photo-thermal effect. The synergistic effect between α-FeOOH and MesoC in α-FeOOH/MesoC composite improved the mineralization efficiency than the mixture catalyst of α-FeOOH and MesoC. The iron leaching is greatly suppressed on the α-FeOOH/MesoC composite. Interestingly, the reused α-FeOOH/MesoC composites showed much higher phenol oxidation and mineralization efficiencies than the fresh catalyst and homogeneous Fenton system (FeSO4/H2O2). The XPS, XRD, FTIR and textural property results reveal that the great enhancement comes from the interfacial emerged oxygen containing groups between α-FeOOH and MesoC after the first heterogeneous Fenton-like reaction. In summary, visible light induced photocatalysis assisted heterogeneous Fenton-like process in the α-FeOOH/MesoC composite system improved the HO• production efficiency and Fe(III)/Fe(II) cycle and further activated the interfacial catalytic sites, which finally realize an extraordinary higher degradation and mineralization efficiency.

  19. Activated carbon-based magnetic TiO2 photocatalyst codoped with iodine and nitrogen for organic pollution degradation

    NASA Astrophysics Data System (ADS)

    Wang, Xuejiang; Song, Jingke; Huang, Jiayu; Zhang, Jing; Wang, Xin; Ma, RongRong; Wang, Jiayi; Zhao, Jianfu

    2016-12-01

    Magnetic photocatalyst - iodine and nitrogen codoped TiO2 based on chitosan decorated magnetic activated carbon (I-N-T/CMAC) was prepared via simple coprecipitation and sol-gel method. The characteristics of photocatalysts were investigated by X-ray diffraction (XRD), N2 adsorption-desorption isotherm, field emission scanning electron microscopy (FESEM), energy dispersive spectrometry (EDS), fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflection spectroscopy (UV-vis DRS), photoluminescence (PL) spectroscopy and vibrating sample magnetometer (VSM). It turned out that the prepared material had large surface area, enhanced absorption of visible light, and magnetically separable properties when mole ratio of I/Ti was 0.1. Iodine-nitrogen codoped magnetic photocatalyst was used for the removal of salicylic acid (SA), and the rate of adsorption reaction for SA by I0.1-N-T/CMAC followed the pseudo second-order kinetic. Under visible light irradiation, 89.71% SA with initial concentration = 30 mg/L could be removed by I0.1-N-T/CMAC, and photodegradation rate of SA on I0.1-N-T/CMAC composites was 0.0084 min-1 which is about 4 times higher than that of magnetic photocatalyst with nitrogen doped only. The effects of SA initial concentration, pH, coexisting anions and humic acid to the degradation of SA with the prepared material were also investigated. Main oxidative species in the photodegradation process are rad OH and h+.

  20. Potentiality of Eisenia fetida to degrade disposable paper cups-an ecofriendly solution to solid waste pollution.

    PubMed

    Arumugam, Karthika; Ganesan, Seethadevi; Muthunarayanan, Vasanthy; Vivek, Swabna; Sugumar, Susila; Munusamy, Vivekanadhan

    2015-02-01

    The aim of the present study was to subject the post-consumer waste, namely paper cups for vermicomposting along with cow dung in three different ratios for a period of 90-140 days employing Eisenia fetida. The post-consumer wastes are a menace in many developing countries including India. This waste was provided as feed for earthworms and was converted to vermicompost. Vermicompost prepared with paper cup waste was analyzed for their physicochemical properties. Based on the physicochemical properties, it was evident that the best manure is obtained from type A (paper cup/cow dung in the ratio 1:1) than type B (paper cup/cow dung in the ratio 1.5:0.5) and type C (paper cup/cow dung in the ratio 0.5:1.5). The results showed that earthworms accelerated the rate of mineralization and converted the wastes into compost with needed elements which could support the growth of crop plants. The predominant bacterial strains in the vermicompost were characterized biochemically as well as by 16S ribosomal RNA (rRNA) gene sequencing. The bacterial strains like Bacillus anthracis (KM289159), Bacillus endophyticus (KM289167), Bacillus funiculus (KM289165), Virigibacillius chiquenigi (KM289163), Bacillus thuringiensis (KM289164), Bacillus cereus (KM289160), Bacillus toyonensis (KM289161), Acinetobacter baumanni (KM289162), and Lactobacillus pantheries (KM289166) were isolated and identified from the final compost. The total protein content of E. fetida involved in vermicomposting was extracted, and the banding pattern was analyzed. During final stages of vermicomposting, it was observed that the earthworm did not act on the plastic material coated inside the paper cups and stagnated it around the rim of the tub. Further, the degradation of paper cup waste was confirmed by Fourier transform infrared spectroscopy analysis. Hence, vermicomposting was found to be an effective technology for the conversion of the paper cup waste material into a nutrient-rich manure, a value

  1. Sono-enhanced degradation of dye pollutants with the use of H2O2 activated by Fe3O4 magnetic nanoparticles as peroxidase mimetic.

    PubMed

    Wang, Nan; Zhu, Lihua; Wang, Mingqiong; Wang, Dali; Tang, Heqing

    2010-01-01

    Sono-enhanced degradation of a dye pollutant Rhodamine B (RhB) was investigated by using H(2)O(2) as a green oxidant and Fe(3)O(4) magnetic nanoparticles (MNPs) as a peroxidase mimetic. It was found that Fe(3)O(4) MNPs could catalyze the break of H(2)O(2) to remove RhB in a wide pH range from 3.0 to 9.0 and its peroxidase-like activity was significantly enhanced by the ultrasound irradiation. At pH 5.0 and temperature 55 degrees C, the ultrasound-assisted H(2)O(2)-Fe(3)O(4) catalysis removed about 95% of RhB (0.02 mmol L(-1)) in 15 min with a apparent rate constant of 0.15 min(-1) for the degradation of RhB, being 6.5 and 37.6 folds of that in the simple catalytic H(2)O(2)-Fe(3)O(4) system, and the simple ultrasonic US-H(2)O(2) systems, respectively. The beneficial synergistic behavior between Fe(3)O(4) catalysis and ultrasonic was demonstrated to be dependent on Fe(3)O(4) dosage, H(2)O(2) concentration, pH value and temperature. As a tentative explanation, the observed significant synergistic effects was attributed to the positive interaction between cavitation effect accelerating the catalytic breakdown of H(2)O(2) over Fe(3)O(4) nanoparticles, and the function of Fe(3)O(4) MNPs providing more nucleation sites for the cavitation inception.

  2. Metal-free catalysis of persulfate activation and organic-pollutant degradation by nitrogen-doped graphene and aminated graphene.

    PubMed

    Chen, Hao; Carroll, Kenneth C

    2016-08-01

    We evaluated three types of functionalized, graphene-based materials for activating persulfate (PS) and removing (i.e., sorption and oxidation) sulfamethoxazole (SMX) as a model emerging contaminant. Although advanced oxidative water treatment requires PS activation, activation requires energy or chemical inputs, and toxic substances are contained in many catalysts. Graphene-based materials were examined herein as an alternative to metal-based catalysts. Results show that nitrogen-doped graphene (N-GP) and aminated graphene (NH2-GP) can effectively activate PS. Overall, PS activation by graphene oxide was not observed in this study. N-GP (50 mg L(-1)) can rapidly activate PS (1 mM) to remove >99.9% SMX within 3 h, and NH2-GP (50 mg L(-1)) activated PS (1 mM) can also remove 50% SMX within 10 h. SMX sorption and total removal was greater for N-GP, which suggests oxidation was enhanced by increasing proximity to PS activation sites. Increasing pH enhanced the N-GP catalytic ability, and >99.9% SMX removal time decreased from 3 h to 1 h when pH increased from 3 to 9. However, the PS catalytic ability was inhibited at pH 9 for NH2-GP. Increases in ionic strength (100 mM NaCl or Na2SO4) and addition of radical scavengers (500 mM ethanol) both had negligible impacts on SMX removal. With bicarbonate addition (100 mM), while the catalytic ability of N-GP remained unaltered, NH2-GP catalytic ability was inhibited completely. Humic acid (250 mg L(-1)) was partially effective in inhibiting SMX removal in both N-GP and NH2-GP systems. These results have implications for elucidating oxidant catalysis mechanisms, and they quantify the ability of functionalization of graphene with hetero-atom doping to effectively catalyze PS for water treatment of organic pollutants including emerging contaminants.

  3. Biological Degradation of Hydrazine.

    DTIC Science & Technology

    1979-10-01

    inhibition of ammonia oxidation at 32 mg/Z. 3 Yoshida and Alexander used neat hydrazine as a selective inhibitor in their studies with Nitrosomonas europaea ...Formation by Nitrosomonas europaea ", Canadian Journal of Microbiology, Vol 10, 1964. 4. Verstraete, W. and M. Alexander, "Heterotrophic Nitrification by...Nitrosgmonas sp. in activated sludge was in general agreement with Meyerhof- who studied pure cultures of Nitrosomonas sp. and found 20-percent

  4. Efficient photocatalytic degradation of organic pollutants by magnetically recoverable nitrogen-doped TiO2 nanocomposite photocatalysts under visible light irradiation.

    PubMed

    Hamzezadeh-Nakhjavani, Sahar; Tavakoli, Omid; Akhlaghi, Seyed Parham; Salehi, Zeinab; Esmailnejad-Ahranjani, Parvaneh; Arpanaei, Ayyoob

    2015-12-01

    Preparation of novel nanocomposite particles (NCPs) with high visible-light-driven photocatalytic activity and possessing recovery potential after advanced oxidation process (AOP) is much desired. In this study, pure anatase phase titania (TiO2) nanoparticles (NPs) as well as three types of NCPs including nitrogen-doped titania (TiO2-N), titania-coated magnetic silica (Fe3O4 cluster@SiO2@TiO2 (FST)), and a novel magnetically recoverable TiO2 nanocomposite photocatalyst containing nitrogen element (Fe3O4 cluster@SiO2@TiO2-N (FST-N)) were successfully synthesized via a sol-gel process. The photocatalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FE-SEM) with an energy-dispersive X-ray (EDX) spectroscopy analysis, X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (DRS), and vibrating sample magnetometer (VSM). The photocatalytic activity of as-prepared samples was further investigated and compared with each other by degradation of phenol, as a model for the organic pollutants, in deionized (DI) water under visible light irradiation. The TiO2-N (55 ± 1.5%) and FST-N (46 ± 1.5%) samples exhibited efficient photocatalytic activity in terms of phenol degradation under visible light irradiation, while undoped samples were almost inactive under same operating conditions. Moreover, the effects of key operational parameters, the optimum sample calcination temperature, and reusability of FST-N NCPs were evaluated. Under optimum conditions (calcination temperature of 400 °C and near-neutral reaction medium), the obtained results revealed efficient degradation of phenol for FST-N NCPs under visible light irradiation (46 ± 1.5%), high yield magnetic separation and efficient reusability of FST-N NCPs (88.88% of its initial value) over 10 times reuse.

  5. Effect of matrix on the electrochemical characteristics of TiO₂ nanotube array-based PbO₂ electrode for pollutant degradation.

    PubMed

    Hu, Zhongxin; Zhou, Minghua; Zhou, Lei; Li, Yunlin; Zhang, Chao

    2014-01-01

    A series of lead dioxide electrodes developed on titania nanotube arrays with different matrix were fabricated by electrodeposition. Before the deposition of PbO₂, the matrix of this anode was electrochemically reduced in (NH₄)₂SO₄ solution and/or pre-deposited with certain amounts of copper. To gain insight into these pretreatments, the PbO₂ electrodes were characterized by SEM, LSV, and XRD, and their electrocatalytic activities for pollutant degradation were compared using p-nitrophenol (p-NP) as a model. It was confirmed that the electrochemical reduction with (NH4)₂SO₄ resulted in the partial conversion of TiO₂ into Ti₄O₇ and Ti₅O₉, which increased the conductivity of PbO₂ anode, but decreased its electrochemical activity, while the Ti/TNTs*-Cu/PbO₂ electrode with both pretreatments possessed the highest oxygen evolution overpotential of 2.5 V (vs. SCE) and low substrate resistance. After a 180-min treatment on this electrode, the removal efficiency of p-NP reached 82.5% and the COD removal achieved 42.5% with the energy consumption of 9.45 kWh m(-3), demonstrating the best performance among these electrodes with different matrices. Therefore, this titania nanotube array-based PbO₂ electrode has a promising application in the industrial wastewater treatment.

  6. Dynamics of the biological properties of soil and the nutrient release of Amorpha fruticosa L. litter in soil polluted by crude oil.

    PubMed

    Zhang, Xiaoxi; Liu, Zengwen; Luc, Nhu Trung; Liang, Xiao; Liu, Xiaobo

    2015-11-01

    Litter from Amorpha fruticosa, a potential phytoremediating plant, was collected and used in a decomposition experiment that involved the litterbag in soil polluted by crude oil. The dynamics of the biological properties of soil and the nutrient release of the litter were detected. The results indicated that (1) in lightly polluted soil (LP, petroleum concentration was 15 g kg(-1)), the bacteria (including actinomycetes), and fungi populations were significant higher than those in unpolluted soil (CK) at the 1st month after pollution, and the bacteria (including actinomycetes) populations were higher than those in the CK at the 6th and 12th months. In moderately polluted soil (MP, 30 g kg(-1)), the bacteria (including actinomycetes) populations were higher than those in the CK at the 1st and 6th months, whereas only the actinomycetes population was greater than that in the CK at the 12th month. In seriously polluted soil (SP, 45 g kg(-1)), only the fungi population was higher than that in the CK at the 6th month. (2) The activities of soil protease, carboxymethyl cellulase, and sucrase were generally inhibited in polluted soil. Peroxidase activity was generally inhibited in the LP and MP soil, and polyphenol oxidase activity was inhibited in the SP soil at 6-12 months. (3) At the end of litter decomposition, the LP soil significantly increased the release rate of all nutrients, except for K. The MP soil reduced the release rate of Fe and Mn, whereas it increased that of C and Cu. The SP soil decreased the release rate of all nutrients except for Cu and Zn. In conclusion, SP by crude oil would lead to limitations in the release of nutrients from the litter and to decreases in the community stability of a phytoremediating plant. A. fruticosa could only be used in phytoremediation of polluted soil at concentrations below 45 g kg(-1) (crude).

  7. Assessment of full-scale biological nutrient removal systems upgraded with physico-chemical processes for the removal of emerging pollutants present in wastewaters from Mexico.

    PubMed

    Estrada-Arriaga, Edson Baltazar; Cortés-Muñoz, Juana Enriqueta; González-Herrera, Arturo; Calderón-Mólgora, César Guillermo; de Lourdes Rivera-Huerta, Ma; Ramírez-Camperos, Esperanza; Montellano-Palacios, Leticia; Gelover-Santiago, Silvia Lucila; Pérez-Castrejón, Sara; Cardoso-Vigueros, Lina; Martín-Domínguez, Alejandra; García-Sánchez, Liliana

    2016-11-15

    Two full-scale biological nutrient removal systems upgraded with three physico-chemical processes (coagulation, chemical precipitation, and neutral Fenton) were evaluated in order to determine the removal of emerging pollutants (EPs) present in municipal wastewater from Mexico. Between 41 and 55 EPs were detected in the influents of two wastewater treatment plants (WWTPs), including personal care products (PPCPs), antibiotics, analgesics, antiepileptics, antilipidemics, antihypertensives, antiseptics, stimulants, and hormones. Emerging pollutants were detected at concentrations ranging from 0.69ng/L to 94,600ng/L. High concentrations of emerging pollutants were found during dry season. WWTP 1, integrated by oxidation ditches and UV light lamps, showed removal efficiencies of EPs between 20% and 22%. On the other hand, WWTP 2 consisted of anaerobic/anoxic/aerobic tanks coupled with two disinfection processes; chlorine dioxide and UV light lamps, for which the removal of EPs was significant (up to 80%). The concentrations of emerging pollutants in WWTP 1 effluent was found within a rangepollutants in the effluent were below 210ng/L. WWTP 2 showed high emerging pollutant removals, compared to those of WWTP 1, due to a greater activity of the simultaneous nitrification-denitrification processes, hydraulic retention time, and solids retention time. The compounds that were more persistent with removals below 50% in both effluents were: carbamazepine, dehydronifedipine, meprobamate, sertraline, propranolol, propoxyphene, norverapamil, diazepam, alprazolam, sulfamethoxazole, metoprolol, ofloxacin, norfloxacin, fluoxetine, erythromycin-H2O, diphenhydramine, dehydronifedipine, clarithromycin, hydrochlorothiazide, and albuterol. The application of neutral Fenton reaction as post-treatment for the two effluents from the WWTPs is promising for the removal of emerging pollutants (up to 100

  8. In vivo degradation behavior and biological activity of some new Mg-Ca alloys with concentration's gradient of Si for bone grafts

    NASA Astrophysics Data System (ADS)

    Trincă, Lucia Carmen; Fântânariu, Mircea; Solcan, Carmen; Trofin, Alina Elena; Burtan, Liviu; Acatrinei, Dumitru Mihai; Stanciu, Sergiu; Istrate, Bogdan; Munteanu, Corneliu

    2015-10-01

    Magnesium based alloys, especially Mg-Ca alloys, are biocompatible substrates with mechanical properties similar to those of bones. The biodegradable alloys of Mg-Ca provide sufficient mechanical strength in load carrying applications as opposed to biopolymers and also they avoid stress shielding and secondary surgery inherent with permanent metallic implant materials. The main issue facing a biodegradable Mg-Ca alloy is the fast degradation in the aggressive physiological environment of the body. The alloy's corrosion is proportional with the dissolution of the Mg in the body: the reaction with the water generates magnesium hydroxide and hydrogen. The accelerated corrosion will lead to early loss of the alloy's mechanical integrity. The degradation rate of an alloy can be improved mainly through tailoring the composition and by carrying out surface treatments. This research focuses on the ability to adjust degradation rate of Mg-Ca alloys by an original method and studies the biological activity of the resulted specimens. A new Mg-Ca alloy, with a Si gradient concentration from the surface to the interior of the material, was obtained. The surface morphology was investigated using scanning electron microscopy (VegaTescan LMH II, SE detector, 30 kV), X-ray diffraction (X'Pert equipment) and energy dispersive X-ray (Bruker EDS equipment). In vivo degradation behavior, biological compatibility and activity of Mg-Ca alloys with/without Si gradient concentration were studied with an implant model (subcutaneous and bony) in rats. The organism response to implants was characterized by using radiological (plain X-rays and computed tomography), biochemical and histological methods of investigation. The results sustained that Si gradient concentration can be used to control the rate of degradation of the Mg-Ca alloys for enhancing their biologic activity in order to facilitate bone tissue repair.

  9. Degradation of a textile reactive azo dye by a combined biological-photocatalytic process: Candida tropicalis Jks2 -Tio2/Uv

    PubMed Central

    2012-01-01

    In the present study, the decolorization and degradation of Reactive Black 5 (RB5) azo dye was investigated by biological, photocatalytic (UV/TiO2) and combined processes. Application of Candida tropicalis JKS2 in treatment of the synthetic medium containing RB5 indicated complete decolorization of the dye with 200 mg/L in less than 24 h. Degradation of the aromatic rings, resulting from the destruction of the dye, did not occur during the biological treatment. Mineralization of 50 mg/L RB5 solution was obtained after 80 min by photocatalytic process (in presence of 0.2 g/L TiO2). COD (chemical oxygen demand) was not detectable after complete decolorization of 50 mg/L RB5 solution. However, photocatalytic process was not effective in the removal of the dye at high concentrations (≥200 mg/L). With 200 mg/L concentration, 74.9% of decolorization was achieved after 4 h illumination under photocatalytic process and the absorbance peak in UV region (attributed to aromatic rings) was not completely removed. A two-step treatment process, namely, biological treatment by yeast followed by photocatalytic degradation, was also assessed. In the combined process (with 200 mg/L RB5), absorbance peak in UV region significantly disappeared after 2 h illumination and about 60% COD removal was achieved in the biological step. It is suggested that the combined process is more effective than the biological and photocatalytic treatments in the remediation of aromatic rings. PMID:23369285

  10. Water treatment by TiO2 photocatalysis and/or ultrasound: degradations of phenyltrifluoromethylketone, a trifluoroacetic-acid-forming pollutant, and octan-1 -ol, a very hydrophobic pollutant.

    PubMed

    Théron, P; Pichat, P; Petrier, C; Guillard, C

    2001-01-01

    TiO2 photocatalysis and ultrasound are advanced oxidation processes for water treatment. Our study aimed at showing, via the purposely chosen title compounds, that these techniques can be complementary. For C6H5COCF3 (PTMK), the photocatalytic removal rate was higher than the ultrasonic (515 kHz) removal rate in the presence of TiO2 in the dark, whereas it was the opposite for octan-1-ol under the conditions employed. Simultaneous UV and ultrasound irradiation of the TiO2 suspension led, for PTMK, to a removal rate about equal to the sum of the removal rates observed for separate irradiations, and decreased by a factor of approximately 20% for octan- 1 -ol as if the photocatalytic degradation was suppressed by the dominant distribution of octan-1-ol to the cavitation bubbles. This distribution was substantiated by the large detrimental effect of octan- 1-ol on the PTMK ultrasonic removal rate. The concurrent use of both techniques allowed a faster removal of both pollutants in binary mixtures. The amount of CF3COOH from PTMK was approximately eight times lower in sonicated, than in UV-irradiated, TiO2 suspensions. Several intermediate products showed the occurrence of chemical transformations occurring in and/or on the cavitation bubbles. COD decline and CO2 formation were initially higher for ultrasonic than for photocatalytic treatment. However, complete mineralization (except for CF3COOH) was achieved more rapidly by photocatalysis and even more rapidly by simultaneous use of both techniques.

  11. Oil shale processing as a source of aquatic pollution: monitoring of the biologic effects in caged and feral freshwater fish.

    PubMed Central

    Tuvikene, A; Huuskonen, S; Koponen, K; Ritola, O; Mauer, U; Lindström-Seppä, P

    1999-01-01

    The biologic effects of the oil shale industry on caged rainbow trout (Oncorhynchus mykiss) as well as on feral perch (Perca fluviatilis) and roach (Rutilus rutilus) were studied in the River Narva in northeast Estonia. The River Narva passes the oil shale mining and processing area and thus receives elevated amounts of polycyclic aromatic hydrocarbons (PAHs), heavy metals, and sulfates. The effects of the chemical load were monitored by measuring cytochrome P4501A (CYP1A)-dependent monooxygenase (MO) activities [7-ethoxyresorufin O-deethylase and aryl hydrocarbon hydroxylase (AHH)] as well as conjugation enzyme activities [glutathione S-transferase (GST) and UDP-glucuronosyltransferase] in the liver of fish. CYP1A induction was further studied by detecting the amount and occurrence of the CYP1A protein. Histopathology of tissues (liver, kidney, spleen, and intestine) and the percentage of micronuclei in fish erythrocytes were also determined. Selected PAHs and heavy metals (Cd, Cu, Hg, and Pb) were measured from fish muscle and liver. In spite of the significant accumulation of PAHs, there was no induction of MO activities in any studied fish species. When compared to reference samples, AHH activities were even decreased in feral fish at some of the exposed sites. Detection of CYP1A protein content and the distribution of the CYP1A enzyme by immunohistochemistry also did not show extensive CYP1A induction. Instead, GST activities were significantly increased at exposed sites. Detection of histopathology did not reveal major changes in the morphology of tissues. The micronucleus test also did not show any evidence of genotoxicity. Thus, from the parameters studied, GST activity was most affected. The lack of catalytic CYP1A induction in spite of the heavy loading of PAHs was not studied but has been attributed to the elevated content of other compounds such as heavy metals, some of which can act as inhibitors for MOs. Another possible explanation of this lack of

  12. Oil shale processing as a source of aquatic pollution: monitoring of the biologic effects in caged and feral freshwater fish.

    PubMed

    Tuvikene, A; Huuskonen, S; Koponen, K; Ritola, O; Mauer, U; Lindström-Seppä, P

    1999-09-01

    The biologic effects of the oil shale industry on caged rainbow trout (Oncorhynchus mykiss) as well as on feral perch (Perca fluviatilis) and roach (Rutilus rutilus) were studied in the River Narva in northeast Estonia. The River Narva passes the oil shale mining and processing area and thus receives elevated amounts of polycyclic aromatic hydrocarbons (PAHs), heavy metals, and sulfates. The effects of the chemical load were monitored by measuring cytochrome P4501A (CYP1A)-dependent monooxygenase (MO) activities [7-ethoxyresorufin O-deethylase and aryl hydrocarbon hydroxylase (AHH)] as well as conjugation enzyme activities [glutathione S-transferase (GST) and UDP-glucuronosyltransferase] in the liver of fish. CYP1A induction was further studied by detecting the amount and occurrence of the CYP1A protein. Histopathology of tissues (liver, kidney, spleen, and intestine) and the percentage of micronuclei in fish erythrocytes were also determined. Selected PAHs and heavy metals (Cd, Cu, Hg, and Pb) were measured from fish muscle and liver. In spite of the significant accumulation of PAHs, there was no induction of MO activities in any studied fish species. When compared to reference samples, AHH activities were even decreased in feral fish at some of the exposed sites. Detection of CYP1A protein content and the distribution of the CYP1A enzyme by immunohistochemistry also did not show extensive CYP1A induction. Instead, GST activities were significantly increased at exposed sites. Detection of histopathology did not reveal major changes in the morphology of tissues. The micronucleus test also did not show any evidence of genotoxicity. Thus, from the parameters studied, GST activity was most affected. The lack of catalytic CYP1A induction in spite of the heavy loading of PAHs was not studied but has been attributed to the elevated content of other compounds such as heavy metals, some of which can act as inhibitors for MOs. Another possible explanation of this lack of

  13. An integrated chemical-biological study using caged mussels (Mytilus trossulus) along a pollution gradient in the Archipelago Sea (SW Finland, Baltic Sea).

    PubMed

    Lehtonen, Kari K; Turja, Raisa; Budzinski, Hélène; Devier, Marie-Hélène

    2016-08-01

    Mussels (Mytilus trossulus) were caged along a known pollution gradient in the inner Archipelago Sea (northern Baltic Sea) and retrieved after 71 and 121 d for the measurement of selected chemical contaminants in tissues and biological endpoints including biochemical biomarkers and growth. Additional samples were collected during the growth season from a native mussel population at an alleged reference site. Elevated concentrations of numerous contaminants (e.g., PAH) were observed in spring, apparently due to the loss of tissue mass during the winter, while also the levels of many biomarkers (e.g., glutathione S-transferase activity) were elevated. Spatial and temporal changes in the accumulation of contaminants and biological parameters were observed with some of them (e.g., growth) linked to seasonal changes in environmental factors. The results underline the importance of understanding the effects of seasonal natural factors on the growth dynamics and general condition of mussels when assessing tissue concentrations of contaminants and biological effects.

  14. AICE Survey of USSR Air Pollution Literature, Volume 15: A Third Compilation of Technical Reports on the Biological Effects and the Public Health Aspects of Atmospheric Pollutants.

    ERIC Educational Resources Information Center

    Nuttonson, M. Y.

    Ten papers were translated: Maximum permissible concentrations of noxious substances in the atmospheric air of populated areas; Some aspects of the biological effect of microconcentrations of two chloroisocyanates; The toxicology of low concentrations of aromatic hydrocarbons; Chronic action of low concentrations of acrolein in air on the…

  15. A biomonitoring study assessing the residual biological effects of pollution caused by the HAVEN wreck on marine organisms in the Ligurian Sea (Italy).

    PubMed

    Viarengo, A; Dondero, F; Pampanin, D M; Fabbri, R; Poggi, E; Malizia, M; Bolognesi, C; Perrone, E; Gollo, E; Cossa, G P

    2007-11-01

    Residual biological effects of the 1991 HAVEN oil spill off the Ligurian (Arenzano) coast were assessed in this study. Samples of the fish species Boops boops, Mullus barbatus, and Uranoscupus scaber were collected from two polluted sites near the HAVEN wreck and from an uncontaminated area. In addition to this, mussels were caged along the coast affected by the HAVEN disaster. The physiological status of fish and mussels was assessed using a battery of stress and exposure biomarkers. The PAH content of mussel and fish tissues was also analyzed. Significant biological responses were observed in lysosomal membrane stability, neutral lipid and lipofuscin accumulation and micronucleus frequency for mussels caged at two sites close to the HAVEN wreck. Chemical analyses indicated, however, that these effects are not caused by aromatic hydrocarbons. For this reason, we suggest that the aftermath of the HAVEN disaster contributes very little to coastal ecosystem pollution. This was also confirmed by the few biological effects observed in fish specimens (Boops boops) collected from surface waters. Nevertheless, it is important to point out that benthic fish displayed a stress syndrome potentially caused by aromatic hydrocarbons released from the oil tanker, as witnessed by an enhanced EROD activity and increased lipofuscin and neutral lipid lysosomal contents.

  16. Viscoelastic and biological performance of low-modulus, reactive calcium phosphate-filled, degradable, polymeric bone adhesives

    PubMed Central

    Abou Neel, Ensanya A.; Salih, Vehid; Revell, Peter A.; Young, Anne M.

    2012-01-01

    The aim of this study was to investigate the effect of reactive mono- and tricalcium phosphate addition on the mechanical, surface free energy, degradation and cell compatibility properties of poly(lactide-co-propylene glycol-co-lactide) dimethacrylate (PPGLDMA) thin films. Dry composites containing up to 70 wt.% filler were in a flexible rubber state at body temperature. Filler addition increased the initial strength and Young’s modulus and reduced the elastic and permanent deformation under load. The polymer had high polar surface free energy, which might enable greater spread upon bone. This was significantly reduced by filler addition but not by water immersion for 7 days. The samples exhibited reduced water sorption and associated bulk degradation when compared with previous work with thicker samples. Their cell compatibility was also improved. Filler raised water sorption and degradation but improved cell proliferation. The materials are promising bone adhesive candidates for low-load-bearing areas. PMID:21884829

  17. Octamer-binding protein 4 affects the cell biology and phenotypic transition of lung cancer cells involving β-catenin/E-cadherin complex degradation.

    PubMed

    Chen, Zhong-Shu; Ling, Dong-Jin; Zhang, Yang-De; Feng, Jian-Xiong; Zhang, Xue-Yu; Shi, Tian-Sheng

    2015-03-01

    Clinical studies have reported evidence for the involvement of octamer‑binding protein 4 (Oct4) in the tumorigenicity and progression of lung cancer; however, the role of Oct4 in lung cancer cell biology in vitro and its mechanism of action remain to be elucidated. Mortality among lung cancer patients is more frequently due to metastasis rather than their primary tumors. Epithelial‑mesenchymal transition (EMT) is a prominent biological event for the induction of epithelial cancer metastasis. The aim of the present study was to investigate whether Oct4 had the capacity to induce lung cancer cell metastasis via the promoting the EMT in vitro. Moreover, the effect of Oct4 on the β‑catenin/E‑cadherin complex, associated with EMT, was examined using immunofluorescence and immunoprecipitation assays as well as western blot analysis. The results demonstrated that Oct4 enhanced cell invasion and adhesion accompanied by the downregulation of epithelial marker cytokeratin, and upregulation of the mesenchymal markers vimentin and N‑cadherin. Furthermore, Oct4 induced EMT of lung cancer cells by promoting β‑catenin/E‑cadherin complex degradation and regulating nuclear localization of β‑catenin. In conclusion, the present study indicated that Oct4 affected the cell biology of lung cancer cells in vitro through promoting lung cancer cell metastasis via EMT; in addition, the results suggested that the association and degradation of the β‑catenin/E‑cadherin complex was regulated by Oct4 during the process of EMT.

  18. Degradation and biological properties of Ca-P contained micro-arc oxidation self-sealing coating on pure magnesium for bone fixation

    PubMed Central

    Wang, Weidan; Wan, Peng; Liu, Chen; Tan, Lili; Li, Weirong; Li, Lugee; Yang, Ke

    2015-01-01

    Poor corrosion resistance is one of the main disadvantages for biodegradable magnesium-based metals, especially applied for bone fixation, where there is a high demand of bio-mechanical strength and stability. Surface coating has been proved as an effective method to control the in vivo degradation. In this study a Ca-P self-sealing micro-arc oxidation (MAO) coating was studied to verify its efficacy and biological properties by in vitro and in vivo tests. It was found that the MAO coating could effectively retard the degradation according to immersion and electrochemical tests as well as 3D reconstruction by X-ray tomography after implantation. The MAO coating exhibited no toxicity and could stimulate the new bone formation. Therefore, the Ca-P self-sealing MAO coating could be a potential candidate for application of biodegradable Mg-based implant in bone fixations. PMID:26816635

  19. Ultrasound (US), Ultraviolet light (UV) and combination (US+UV) assisted semiconductor catalysed degradation of organic pollutants in water: oscillation in the concentration of hydrogen peroxide formed in situ.

    PubMed

    Jyothi, K P; Yesodharan, Suguna; Yesodharan, E P

    2014-09-01

    Application of Advanced Oxidation Processes (AOP) such as sono, photo and sonophoto catalysis in the purification of polluted water under ambient conditions involve the formation and participation of Reactive Oxygen Species (ROS) like ·OH, HO2·, O2(-), H2O2 etc. Among these, H2O2 is the most stable and is also a precursor for the reactive free radicals. Current investigations on the ZnO mediated sono, photo and sonophoto catalytic degradation of phenol pollutant in water reveal that H2O2 formed in situ cannot be quantitatively correlated with the degradation of the pollutant. The concentration of H2O2 formed does not increase corresponding to phenol degradation and reaches a plateau or varies in a wave-like fashion (oscillation) with well defined crests and troughs, indicating concurrent formation and decomposition. The concentration at which decomposition overtakes formation or formation overtakes decomposition is sensitive to the reaction conditions. Direct photolysis of H2O2 in the absence of catalyst or the presence of pre-equilibrated (with the adsorption of H2O2) catalyst in the absence of light does not lead to the oscillation. The phenomenon is more pronounced in sonocatalysis, the intensity of oscillation being in the order sonocatalysis>photocatalysis⩾sonophotocatalysis while the degradation of phenol follows the order sonophotocatalysis>photocatalysis>sonocatalysis>sonolysis>photolysis. In the case of sonocatalysis, the oscillation continues for some more time after discontinuing the US irradiation indicating that the reactive free radicals as well as the trapped electrons and holes which interact with H2O2 have longer life time (memory effect).

  20. Chemical composition, nitrogen degradability and in vitro ruminal biological activity of tannins in vines harvested from four tropical sweet potato (Ipomoea batatas L.) varieties.

    PubMed

    Ali, R; Mlambo, V; Mangwe, M C; Dlamini, B J

    2016-02-01

    This study investigated the potential of vines from four sweet potato varieties (Tia Nong 57, Tia Nong 66, Ligwalagwala and Kenya) as alternative feed resources for ruminant livestock. The chemical composition [neutral detergent fibre (NDF), acid detergent fibre (ADF), crude protein (CP) and acid detergent insoluble nitrogen (ADIN)], in vitro ruminal nitrogen (N) degradability and in vitro ruminal biological activity of tannins in the vines, harvested at 70 and 110 days after planting (DAP), were determined. Variety and harvesting stage did not (p > 0.05) influence CP and NDF content of the vines. Concentration of CP ranged from 104.9 to 212.2 g/kg DM, while NDF ranged from 439.4 to 529.2 g/kg DM across harvesting stages and varieties. Nitrogen degradability (ND) at 70 and 110 DAP was highest (p < 0.05) in Ligwalagwala (743.1 and 985.0 g/kg DM, respectively). Treatment of vines with tannin-binding polyethylene glycol (PEG) increased (p < 0.05) in vitro ruminal cumulative gas production parameters (a, b and c). The in vitro ruminal biological activity of tannins, as measured by increment in gas production parameters upon PEG inclusion, had a maximum value of 18.2%, suggesting low to moderate antinutritional tannin activity. Ligwalagwala vines, with highly degradable N, would be the best protein supplement to use during the dry season when ruminant animals consume low N basal diets and maintenance is an acceptable production objective. Tia Nong 66 and Kenya varieties, with less degradable N, may be more suitable for use as supplements for high-producing animals such as dairy goats.

  1. Dynamics of ecological and biological characteristics of soddy-podzolic soils under long-term oil pollution

    NASA Astrophysics Data System (ADS)

    Petrov, A. M.; Versioning, A. A.; Karimullin, L. K.; Akaikin, D. V.; Tarasov, O. Yu.

    2016-07-01

    The dynamics of respiratory and enzyme activities and toxicological properties of loamy-sandy and loamy soddy-podzolic soils (Retisols) under the long-term influence of oil pollution were studied. The concentrations of the pollutant, at which the activity (the ability of self-purification) of the indigenous soil microflora is preserved, were determined. The dynamics of the decrease of oil product content and the time of elimination of the toxic effects on higher plants at the initial pollutant contents were revealed. The parameters of the respiratory and enzyme activities in the course of the 365-day experiment showed that the microbial community of the loamy-sandy soil was more sensitive to oil pollution. The phytotoxic characteristics of the oil-containing loamy-sandy and loamy soils did not correlate with their respiratory and enzyme activities. This fact testifies to some differences in the mechanisms of their influence on living organisms with different organizational levels and to the necessity of taking into account a complex of parameters when assessing the state of the soils under the long-term effects of oil and its products.

  2. Eutrophication. [Water pollution

    SciTech Connect

    Medine, A.J.; Porcella, D.B.

    1982-06-01

    A literature review dealing with the process of eutrophication with respect to the sources and transport of pollutants is presented. Topics include the mathematical modeling of nutrient loading, eutrophication, and aquatic ecosystems. Biological and environmental indicators of eutrophication are reviewed, and the interactions between various chemical and biological pollutants are considered. Several lake management projects are discussed. (KRM)

  3. Poly(Beta-Hydroxybutyrate) Stereoisomers: A Model Study of the Effects of Stereochemical and Morphological Variables on Polymer Biological Degradability

    DTIC Science & Technology

    1992-01-01

    sole source of carbon. The bacterial ybutyrate), (R)-PHB, which is a highly crystalline bio- strains Pseudomonas ?remoignei (ATCC 17989)15-18 and...degradable thermoplastic.8 Alcaligenes faecalis T1,1s9A isolated from soil and activated Several researchers have studied the depolymerization sewage sludge

  4. Speciation and formation of iodinated trihalomethane from microbially derived organic matter during the biological treatment of micro-polluted source water.

    PubMed

    Wei, Yuanyuan; Liu, Yan; Ma, Luming; Wang, Hongwu; Fan, Jinhong; Liu, Xiang; Dai, Rui-Hua

    2013-09-01

    Water sources are micro-polluted by the increasing range of anthropogenic activities around them. Disinfection byproduct (DBP) precursors in water have gradually expanded from humic acid (HA) and fulvic acid to other important sources of potential organic matter. This study aimed to provide further insights into the effects of microbially derived organic matter as precursors on iodinated trihalomethane (I-THM) speciation and formation during the biological treatment of micro-polluted source water. The occurrence of I-THMs in drinking water treated by biological processes was investigated. The results showed for the first time that CHCl2I and CHBrClI are emerging DBPs in China. Biological pre-treatment and biological activated carbon can increase levels of microbes, which could serve as DBP precursors. Chlorination experiments with bovine serum albumin (BSA), starch, HA, deoxyribonucleic acid (DNA), and fish oil, confirmed the close correlation between the I-THM species identified during the treatment processes and those predicted from the model compounds. The effects of iodide and bromide on the I-THM speciation and formation were related to the biochemical composition of microbially derived organic precursors. Lipids produced up to 16.98μgL(-1) of CHCl2I at an initial iodide concentration of 2mgL(-1). HA and starch produced less CHCl2I at 3.88 and 3.54μgL(-1), respectively, followed by BSA (1.50μgL(-1)) and DNA (1.35μgL(-1)). Only fish oil produced I-THMs when iodide and bromide were both present in solution; the four other model compounds formed brominated species.

  5. A full-scale study on thermal degradation of polychlorinated dibenzo- p-dioxins and dibenzofurans in municipal solid waste incinerator fly ash and its secondary air pollution control in China.

    PubMed

    Gao, Xingbao; Ji, Bingjing; Yan, Dahai; Huang, Qifei; Zhu, Xuemei

    2017-04-01

    Degradation of polychlorinated dibenzo- p-dioxins and dibenzofurans in municipal solid waste incinerator fly ash is beneficial to its risk control. Fly ash was treated in a full-scale thermal degradation system (capacity 1 t d(-1)) to remove polychlorinated dibenzo- p-dioxins and dibenzofurans. Apart from the confirmation of the polychlorinated dibenzo- p-dioxin and dibenzofuran decomposition efficiency, we focused on two major issues that are the major obstacles for commercialising this decomposition technology in China, desorption and regeneration of dioxins and control of secondary air pollution. The toxic equivalent quantity values of polychlorinated dibenzo- p-dioxins and dibenzofurans decreased to <6 ng kg(-1) and the detoxification rate was ⩾97% after treatment for 1 h at 400 °C under oxygen-deficient conditions. About 8.49% of the polychlorinated dibenzo- p-dioxins and dibenzofurans in toxic equivalent quantity (TEQ) of the original fly ash were desorbed or regenerated. The extreme high polychlorinated dibenzo- p-dioxin and dibenzofuran levels and dibenzo- p-dioxin and dibenzofuran congener profiles in the dust of the flue gas showed that desorption was the main reason, rather than de novo synthesis of polychlorinated dibenzo- p-dioxins and dibenzofurans in the exhaust pipe. Degradation furnace flue gas was introduced to the municipal solid waste incinerator economiser, and then co-processed in the air pollution control system. The degradation furnace released relatively large amounts of cadmium, lead and polychlorinated dibenzo- p-dioxins and dibenzofurans compared with the municipal solid waste incinerator, but the amounts emitted to the atmosphere did not exceed the Chinese national emission limits. Thermal degradation can therefore be used as a polychlorinated dibenzo- p-dioxin and dibenzofuran abatement method for municipal solid waste incinerator source in China.

  6. Genetic organization of the catabolic plasmid pJP4 from Ralstonia eutropha JMP134 (pJP4) reveals mechanisms of adaptation to chloroaromatic pollutants and evolution of specialized chloroaromatic degradation pathways.

    PubMed

    Trefault, N; De la Iglesia, R; Molina, A M; Manzano, M; Ledger, T; Pérez-Pantoja, D; Sánchez, M A; Stuardo, M; González, B

    2004-07-01

    Ralstonia eutropha JMP134 (pJP4) is a useful model for the study of bacterial degradation of substituted aromatic pollutants. Several key degrading capabilities, encoded by tfd genes, are located in the 88 kb, self-transmissible, IncP-1 beta plasmid pJP4. The complete sequence of the 87,688 nucleotides of pJP4, encoding 83 open reading frames (ORFs), is reported. Most of the coding sequence corresponds to a well-conserved IncP-1 beta backbone and the previously reported tfd genes. In addition, we found hypothetical proteins putatively involved in the transport of aromatic compounds and short-chain fatty acid oxidation. ORFs related to mobile elements, including the Tn501-encoded mercury resistance determinants, an IS1071-based composite transposon and a cryptic class II transposon, are also present in pJP4. These mobile elements are inefficient in transposition and are located in two regions of pJP4 that are rich in remnants of lateral gene transfer events. pJP4 plasmid was able to capture chromosomal genes and form hybrid plasmids with the IncP-1 alpha plasmid RP4. These observations are integrated into a model for the evolution of pJP4, which reveals mechanisms of bacterial adaptation to degrade pollutants.

  7. Can mangrove plantation enhance the functional diversity of macrobenthic community in polluted mangroves?

    PubMed

    Leung, Jonathan Y S; Cheung, Napo K M

    2017-03-15

    Mangrove plantation is widely applied to re-establish the plant community in degraded mangroves, but its effectiveness to restore the ecological functions of macrobenthic community remains poorly known, especially when pollution may overwhelm its potential positive effect. Here, we tested the effect of mangrove plantation on the ecological functions of macrobenthic community in a polluted mangrove by analyzing biological traits of macrobenthos and calculating functional diversity. Mangrove plantation was shown to enhance the functional diversity and restore the ecological functions of macrobenthic community, depending on seasonality. Given the polluted sediment, however, typical traits of opportunistic species (e.g. small and short-lived) prevailed in all habitats and sampling times. We conclude that mangrove plantation can help diversify the ecological functions of macrobenthic community, but its effectiveness is likely reduced by pollution. From the management perspective, therefore, pollution sources must be stringently regulated and mangrove plantation should be conducted to fully recover degraded mangroves.

  8. A biological method to monitor early effects of the air pollution caused by the industrial exploitation of geothermal energy.

    PubMed

    Paoli, Luca; Loppi, Stefano

    2008-09-01

    The suitability of a set of ecophysiological parameters, to be used as early warning indicator to detect signs of a worsening environment around geothermal power plants, was tested by comparison with the diversity of epiphytic lichens, a well-established indicator of geothermal air pollution. Samples of the lichen Evernia prunastri were transplanted around a geothermal power plant at Larderello (Tuscany, Italy) and at a control site, and integrity of cell membranes, concentration of chlorophyll a, b and carotenoids, chlorophyll integrity and variations in pH of thalli were measured. The results showed that cell membrane damage, expressed by changes in electrical conductivity, could be used to detect early (exposure periods as short as 1 month) deleterious effects of geothermal air pollution.

  9. Development of biological indices for identifying and evaluating impacts of pollutants on freshwater ecosystems. Final report, June 1975-October 1980

    SciTech Connect

    Cairns, J. Jr.; Cherry, D.S.

    1980-09-30

    The ten Research Areas reported included: (1) the development of functional indices for identifying and evaluating impacts of pollutants on Aufwuchs communities, (2) relationship of protozoan colonization rates to the eutrophication process, (3) testing of methods to determine the functioning of zooplankton communities subjected to entrainment stress, (4) the use of the first steps of detritus processing (microbial decomposition) as a technique for assessing pollutional stress on aquatic communities in a river system, (5) relationship of protozoan invasion and extinction rate to the eutrophication process, (6) extension of present early colonization studies to the simultaneous evaluation of natural environmental parameters and power plant effluents and application of the early colonization approach to microbial communities in streams of the New River drainage, (7) testing of single species-community responses of protozoans from selected heavy metals, (8) the effects of selected power plant pollutants on grazer utilization of Aufwuchs, (9) investigation of bioconcentration and bioaccumulation mechanisms of the Asiatic clam (Corbicula fluminea) populations in field artificial streams and laboratory microcosms with reference to physical chemistry and diet alterations, and (10) investigation of the homeostatic regulation in bluegill sunfish following acute hypothermal shock and to other power plant related effluents.

  10. A study of air pollution with heavy metals in Athens city and Attica basin using evergreen trees as biological indicators.

    PubMed

    Sawidis, Thomas; Krystallidis, Panagiotis; Veros, Dimitrios; Chettri, Mukesh

    2012-09-01

    Concentrations of five metals (cadmium, chromium, copper, nickel and lead) were determined in tree leaves collected from 13 areas of the Attica basin and Athens city, Greece. Geographical distribution patterns were investigated, and factors affecting toxic element accumulation in trees were discussed. The mean heavy metal content in the tree leaves is described in the descending order of copper>lead>nickel>chromium>cadmium. Generally, the most damaged areas have been proved to be those near the city center and in the vicinity of the Attica highway. The geomorphological relief of the area plays an important role in the dispersion of airborne particles from pollution sources to the surrounding area. Areas on the NE region are also polluted mainly due to wind directions. In Citrus aurantium leaves, with relatively impermeable cuticle, high chromium, copper and nickel concentration would be possibly caused only by significant stomatal uptake. The conifer tree Pinus brutia providing a rough leaf surface also showed elevated concentrations, especially of cadmium and lead. The thick waxy cuticle of the sclerophyllous broad-leaved Olea europaea forms a smooth sheet increasing the barrier properties of the leaf epidermis and causing a reduction in leaf permeability. The dense trichomes of the abaxial epidermis of Olea europaea also act as a pollution screen keeping away the air particles from the epidermis stomata. The presence of a certain metal within the leaf cells could reduce the uptake or toxicity of some others.

  11. Impact of Insulin Degrading Enzyme and Neprilysin in Alzheimer's Disease Biology: Characterization of Putative Cognates for Therapeutic Applications.

    PubMed

    Jha, Niraj Kumar; Jha, Saurabh Kumar; Kumar, Dhiraj; Kejriwal, Noopur; Sharma, Renu; Ambasta, Rashmi K; Kumar, Pravir

    2015-01-01

    Alzheimer's disease (AD) is a neurodegenerative process primarily characterized by amyloid-β (Aβ) agglomeration, neuroinflammation, and cognitive dysfunction. The prominent cause for dementia is the deposition of Aβ plaques and tau-neurofibrillary tangles that hamper the neuronal organization and function. Aβ pathology further affects numerous signaling cascades that disturb the neuronal homeostasis. For instance, Aβ deposition is responsible for altered expression of insulin encoding genes that lead to insulin resistance, and thereby affecting insulin signaling pathway and glucose metabolism in the brain. As a result, the common pathology of insulin resistance between Type-2 diabetes mellitus and AD has led AD to be proposed as a form of diabetes and termed 'Type-3 diabetes'. Since accumulation of Aβ is the prominent cause of neuronal toxicity in AD, its clearance is the prime requisite for therapeutic prospects. This purpose is expertly fulfilled by the potential role of Aβ degrading enzymes such as insulin degrading enzyme (IDE) and Neprilysin (NEP). Therefore, their molecular study is important to uncover the proteolytic and regulatory mechanism of Aβ degradation. Herein, (i) In silico sequential and structural analysis of IDE and NEP has been performed to identify the molecular entities for proteolytic degradation of Aβ in the AD brain, (ii) to analyze their catalytic site to demonstrate the enzymatic action played by IDE and NEP, (iii) to identify their structural homologues that could behave as putative partners of IDE and NEP with similar catalytic action and (iv) to illustrate various IDE- and NEP-mediated therapeutic approaches and factors for clearing Aβ in AD.

  12. Environmental parameters of the Tennessee River in Alabama. 2: Physical, chemical, and biological parameters. [biological and chemical effects of thermal pollution from nuclear power plants on water quality

    NASA Technical Reports Server (NTRS)

    Rosing, L. M.

    1976-01-01

    Physical, chemical and biological water quality data from five sites in the Tennessee River, two in Guntersville Reservoir and three in Wheeler Reservoir were correlated with climatological data for three annual cycles. Two of the annual cycles are for the years prior to the Browns Ferry Nuclear Power Plant operations and one is for the first 14 months of Plant operations. A comparison of the results of the annual cycles indicates that two distinct physical conditions in the reservoirs occur, one during the warm months when the reservoirs are at capacity and one during the colder winter months when the reservoirs have been drawn-down for water storage during the rainy months and for weed control. The wide variations of physical and chemical parameters to which the biological organisms are subjected on an annual basis control the biological organisms and their population levels. A comparison of the parameters of the site below the Power plant indicates that the heated effluent from the plant operating with two of the three reactors has not had any effect on the organisms at this site. Recommendations given include the development of prediction mathematical models (statistical analysis) for the physical and chemical parameters under specific climatological conditions which affect biological organisms. Tabulated data of chemical analysis of water and organism populations studied is given.

  13. One dimensional CdS nanowire@TiO2 nanoparticles core-shell as high performance photocatalyst for fast degradation of dye pollutants under visible and sunlight irradiation.

    PubMed

    Arabzadeh, Abbas; Salimi, Abdollah

    2016-10-01

    In this study, one-dimensional CdS nanowires@TiO2 nanoparticles core-shell structures (1D CdS NWs@TiO2 NPs) were synthesized by a facile wet chemical-solvothermal method. The different aspects of the properties of CdS NWs@TiO2 NPs were surveyed by using a comprehensive range of characterization techniques including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV-vis spectroscopy, scanning electron microscopy (SEM), fluorescence spectroscopy, energy dispersive X-ray spectroscopy (EDX), Cyclic Voltammetry (CV) and amperometry. The as-prepared nanostructure was applied as an effective photocatalyst for degradation of methyl orange (MO), methylene blue (MB) and rhodamine B (Rh B) under visible and sunlight irradiation. The results indicated significantly enhanced photocatalytic activity of CdS NWs@TiO2 NPs for degradation of MO, MB and Rh B compared to CdS NWs. The enhanced photocatalytic activity could be attributed to the enhanced sunlight absorbance and the efficient charge separation of the formed heterostructure between CdS NWs and TiO2. The results showed that MO, Rh B and MB were almost completely degraded after 2, 2 and 3min of exposure to sunlight, respectively; while under visible light irradiation (3W blue LED lamp) the dyes were decomposed with less half degradation rate. The catalytic activity was retained even after three degradation cycles of organic dyes, demonstrating that the proposed nanocomposite can be effectively used as efficient photocatalyst for removal of environmental pollutions caused by organic dyes under sunlight irradiation and it could be an important addition to the field of wastewater treatment. We hope the present study may open a new window of such 1-D semiconductor nanocomposites to be used as visible light photocatalysts in the promising field of organic dyes degradation.

  14. Degradation of the electrospun silica nanofiber in a biological medium for primary hippocampal neuron – effect of surface modification

    PubMed Central

    Feng, Z Vivian; Chen, Wen Shuo; Keratithamkul, Khomson; Stoick, Michael; Kapala, Brittany; Johnson, Eryn; Huang, An-Chi; Chin, Ting Yu; Chen-Yang, Yui Whei; Yang, Mong-Lin

    2016-01-01

    In this work, silica nanofibers (SNFs) were prepared by an electrospinning method and modified with poly-d-lysine (PDL) or (3-aminopropyl) trimethoxysilane (APTS) making biocompatible and degradable substrates for neuronal growth. The as-prepared SNF, modified SNF-PDL, and SNF-APTS were evaluated using scanning electron microscopy, nitrogen adsorption/desorption isotherms, contact angle measurements, and inductively coupled plasma atomic emission spectroscopy. Herein, the scanning electron microscopic images revealed that dissolution occurred in a corrosion-like manner by enlarging porous structures, which led to loss of structural integrity. In addition, covalently modified SNF-APTS with more hydrophobic surfaces and smaller surface areas resulted in significantly slower dissolution compared to SNF and physically modified SNF-PDL, revealing that different surface modifications can be used to tune the dissolution rate. Growth of primary hippocampal neuron on all substrates led to a slower dissolution rate. The three-dimensional SNF with larger surface area and higher surface density of the amino group promoted better cell attachment and resulted in an increased neurite density. This is the first known work addressing the degradability of SNF substrate in physiological conditions with neuron growth in vitro, suggesting a strong potential for the applications of the material in controlled drug release. PMID:27013873

  15. [Progress of research on the microbial fuel cells in the application of environment pollution treatment--a review].

    PubMed

    Yang, Yonggang; Sun, Guoping; Xu, Meiying

    2010-07-01

    Microbial fuel cells (MFCs) are bio-electrochemical reactors that have the capacity to convert chemical energy of biodegradable organic chemicals to electrical energy, and developed rapidly in the past few years. With an increasing concern for energy crisis and environment pollution, MFCs has became a promising technology in the researches of environment pollution treatments and biology electricity. In this paper, we offered a comprehensive review of the recent research progress of MFCs in environment pollution treatment, includes denitrification, desufurization, organic pollutants degradation, heavy metal reduction and landfill leachate treatment. Also, we pointed out the challenges and problems which were bottle necks for a wide application of MFCs and the potential future development.

  16. The Oceanus statue of the Fontana di Trevi (Rome): The analysis of black crust as a tool to investigate the urban air pollution and its impact on the stone degradation.

    PubMed

    La Russa, Mauro F; Fermo, Paola; Comite, Valeria; Belfiore, Cristina M; Barca, Donatella; Cerioni, Annamaria; De Santis, Marina; Barbagallo, Lorena Francesca; Ricca, Michela; Ruffolo, Silvestro A

    2017-03-24

    This paper deals with the analysis of black crust coming from the statue of Oceanus belonging to the Fontana di Trevi (Rome). This monument is undoubtedly one of the main touristic attractions of Rome. During the restoration held between 2014 and 2015, some diagnostic analyses had been carried out. It has been highlighted that the sheltered surfaces suffer the formation of black crust, especially on the marble statues. The possibility to sample those degradation products, together with the unaltered substrate, represented an excellent opportunity to characterize the marble itself, to assess the impact of the urban air pollution on the stone material, and to detect the pollutant on a precise timescale. In fact, it is known that the previous restoration of the fountain had been carried out between 1989 and 1991 then, information about the air pollution over the last 25years can be highlighted, because it has been proved that black crusts act as passive samplers of pollution. In order to fully characterize those samples, several techniques were used, including optical and scanning electron microscopy, X-ray diffraction, laser ablation inductively coupled plasma mass spectrometry, infrared spectroscopy and ion chromatography. Furthermore, a new methodology based on CHN (Carbon, Hydrogen, Nitrogen) analysis has been developed for the quantification of the two main constituents of the carbonaceous fraction present in the black crusts, i.e. OC (organic carbon) and EC (elemental carbon). This integrated approach proposed in the present study allowed us to gain information about the mineralogical phases and the elements within the crusts and at the crust-substrate interface, giving the possibility to identify the pollution sources causing the stone decay within the monument.

  17. White-faced storm-petrels Pelagodroma marina predated by gulls as biological monitors of plastic pollution in the pelagic subtropical Northeast Atlantic.

    PubMed

    Furtado, Ricardo; Menezes, Dilia; Santos, Carolina Jardim; Catry, Paulo

    2016-11-15

    Marine plastic pollution is rapidly growing and is a source of major concern. Seabirds often ingest plastic debris and are increasingly used as biological monitors of plastic pollution. However, virtually no studies have assessed plastics in seabirds in the deep subtropical North Atlantic. We investigated whether remains of white-faced storm-petrels (WFSP) present in gull pellets could be used for biomonitoring. We analysed 263 pellets and 79.0% of these contained plastic debris originating in the digestive tract of WFSP. Pellets with no bird prey did not contain plastics. Most debris were fragments (83.6%) with fewer plastic pellets (8.2%). Light-coloured plastics predominated (71.0%) and the most frequent polymer was HDPE (73.0%). Stable isotopes in toe-nails of WFSP containing many versus no plastics did not differ, indicating no individual specialisation leading to differential plastic ingestion. We suggest WFSP in pellets are highly suitable to monitor the little known pelagic subtropical Northeast Atlantic.

  18. [Treatment of oilfield produced water by biological methods-constructed wetland process and degradation characteristics of organic substances].

    PubMed

    Huang, Xiang-feng; Shen, Jie; Wen, Yue; Liu, Jia; Lu, Li-jun; Zhou, Qi

    2010-02-01

    Hydrolysis acidification-aerobic-constructed wetland process and hydrolysis acidification-constructed wetland were used to treat oilfield produced water after the pretreatment of oil separation-coagulation. Gas chromatography-mass spectrometry was used to study the degradation characteristics of organic substances during the treatment process. The results showed that COD and ammonia nitrogen of both the two process effluents were below 80 mg/L and 15 mg/L, respectively, when HRT was 20 h for hydrolysis acidification, 10 h for aeration and 2 d for constructed wetlands or when HRT was 20 h for hydrolysis acidification and 4 d for constructed wetland. The results of GC-MS analysis showed that biodegradability of the oil produced water was significantly improved in hydrolysis acidification. Substantial removal of benzene compounds was achieved in aerobic and constructed wetland.

  19. Bioremediation of hydrocarbon degradation in a petroleum-contaminated soil and microbial population and activity determination.

    PubMed

    Wu, Manli; Li, Wei; Dick, Warren A; Ye, Xiqiong; Chen, Kaili; Kost, David; Chen, Liming

    2017-02-01

    Bioremediation of hydrocarbon degradation in petroleum-polluted soil is carried out by various microorganisms. However, little information is available for the relationships between hydrocarbon degradation rates in petroleum-contaminated soil and microbial population and activity in laboratory assay. In a microcosm study, degradation rate and efficiency of total petroleum hydrocarbons (TPH), alkanes, and polycyclic aromatic hydrocarbons (PAH) in a petroleum-contaminated soil were determined using an infrared photometer oil content analyzer and a gas chromatography mass spectrometry (GC-MS). Also, the populations of TPH, alkane, and PAH degraders were enumerated by a modified most probable number (MPN) procedure, and the hydrocarbon degrading activities of these degraders were determined by the Biolog (MT2) MicroPlates assay. Results showed linear correlations between the TPH and alkane degradation rates and the population and activity increases of TPH and alkane degraders, but no correlation was observed between the PAH degradation rates and the PAH population and activity increases. Petroleum hydrocarbon degrading microbial population measured by MPN was significantly correlated with metabolic activity in the Biolog assay. The results suggest that the MPN procedure and the Biolog assay are efficient methods for assessing the rates of TPH and alkane, but not PAH, bioremediation in oil-contaminated soil in laboratory.

  20. Hybridization of Cd0.2Zn0.8S with g-C3N4 nanosheets: a visible-light-driven photocatalyst for H2 evolution from water and degradation of organic pollutants.

    PubMed

    Liu, Hong; Jin, Zhitong; Xu, Zhengzheng

    2015-08-28

    Novel visible-light-driven Cd0.2Zn0.8S/g-C3N4 inorganic-organic composite photocatalysts were synthesized by a facile hydrothermal method. The prepared Cd0.2Zn0.8S/g-C3N4 composites were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), ultraviolet-visible diffuse reflection spectroscopy (DRS), photoluminescence (PL) spectroscopy and photoelectrochemical (PEC) experiments. Under visible-light irradiation, Cd0.2Zn0.8S/g-C3N4 photocatalysts displayed a higher photocatalytic activity than pure g-C3N4 and Cd0.2Zn0.8S for hydrogen evolution and degradation of pollutants, and the optimal g-C3N4 content was 20 wt%. The optimal composite showed a hydrogen evolution rate of 208.0 μmol h(-1). The enhancement of the photocatalytic activity should be attributed to the well-matched band structure and intimate contact interfaces between Cd0.2Zn0.8S and g-C3N4, which lead to the effective transfer and separation of the photogenerated charge carriers. Furthermore, the Cd0.2Zn0.8S/g-C3N4 photocatalysts showed excellent stability during photocatalytic hydrogen evolution and degradation of pollutants.

  1. Assessment of multi-chemical pollution in aquatic ecosystems using toxic units: compound prioritization, mixture characterization and relationships with biological descriptors.

    PubMed

    Ginebreda, Antoni; Kuzmanovic, Maja; Guasch, Helena; de Alda, Miren López; López-Doval, Julio C; Muñoz, Isabel; Ricart, Marta; Romaní, Anna M; Sabater, Sergi; Barceló, Damià

    2014-01-15

    Chemical pollution is typically characterized by exposure to multiple rather than to single or a limited number of compounds. Parent compounds, transformation products and other non-targeted compounds yield mixtures whose composition can only be partially identified by monitoring, while a substantial proportion remains unknown. In this context, risk assessment based on the application of additive ecotoxicity models, such as concentration addition (CA), is rendered somewhat misleading. Here, we show that ecotoxicity risk information can be better understood upon consideration of the probabilistic distribution of risk among the different compounds. Toxic units of the compounds identified in a sample fit a lognormal probability distribution. The parameters characterizing this distribution (mean and standard deviation) provide information which can be tentatively interpreted as a measure of the toxic load and its apportionment among the constituents in the mixture (here interpreted as mixture complexity). Furthermore, they provide information for compound prioritization tailored to each site and enable prediction of some of the functional and structural biological variables associated with the receiving ecosystem. The proposed approach was tested in the Llobregat River basin (NE Spain) using exposure and toxicity data (algae and Daphnia) corresponding to 29 pharmaceuticals and 22 pesticides, and 5 structural and functional biological descriptors related to benthic macroinvertebrates (diversity, biomass) and biofilm metrics (diatom quality, chlorophyll-a content and photosynthetic capacity). Aggregated toxic units based on Daphnia and algae bioassays provided a good indication of the pollution pattern of the Llobregat River basin. Relative contribution of pesticides and pharmaceuticals to total toxic load was variable and highly site dependent, the latter group tending to increase its contribution in urban areas. Contaminated sites' toxic load was typically dominated by

  2. Enzyme Based Biosensors for Detection of Environmental Pollutants--A Review.

    PubMed

    Nigam, Vinod Kumar; Shukla, Pratyoosh

    2015-11-01

    Environmental security is one of the major concerns for the safety of living organisms from a number of harmful pollutants in the atmosphere. Different initiatives, legislative actions, as well as scientific and social concerns have been discussed and adopted to control and regulate the threats of environmental pollution, but it still remains a worldwide challenge. Therefore, there is a need for developing certain sensitive, rapid, and selective techniques that can detect and screen the pollutants for effective bioremediation processes. In this perspective, isolated enzymes or biological systems producing enzymes, as whole cells or in immobilized state, can be used as a source for detection, quantification, and degradation or transformation of pollutants to non-polluting compounds to restore the ecological balance. Biosensors are ideal for the detection and measurement of environmental pollution in a reliable, specific, and sensitive way. In this review, the current status of different types of microbial biosensors and mechanisms of detection of various environmental toxicants are discussed.

  3. Towards habitat-oriented systems biology of "Aromatoleum aromaticum" EbN1: chemical sensing, catabolic network modulation and growth control in anaerobic aromatic compound degradation.

    PubMed

    Rabus, Ralf; Trautwein, Kathleen; Wöhlbrand, Lars

    2014-04-01

    The denitrifying betaproteobacterium "Aromatoleum aromaticum" EbN1 is a well-studied model organism for anaerobic degradation of aromatic compounds. Following publication of its genome in 2005, comprehensive physiological-proteomic studies were conducted to deduce functional understanding from the genomic blueprint. A catabolic network (85 predicted, 65 identified proteins) for anaerobic degradation of 24 aromatic growth substrates (including 11 newly recognized) was established. Newly elucidated pathways include those for 4-ethylphenol and plant-derived 3-phenylpropanoids, involving functional assignment of several paralogous genes. The substrate-specific regulation of individual peripheral degradation pathways is probably initiated by highly specific chemical sensing via dedicated sensory/regulatory proteins, e.g. three different σ⁵⁴-dependent one-component sensory/regulatory proteins are predicted to discriminate between three phenolic substrates (phenol, p-cresol and 4-ethylphenol) and two different two-component systems are assumed to differentiate between two alkylbenzenes (toluene, ethylbenzene). Investigations under in situ relevant growth conditions revealed (a) preferred utilization of benzoate from a mixture with succinate results from repressed synthesis of a C₄-dicarboxylate TRAP transporter; (b) response to alkylbenzene-induced solvent stress comprises metabolic re-routing of acetyl-CoA and reducing equivalents to poly(3-hydroxybutyrate) synthesis, alteration of cellular membrane composition and formation of putative solvent efflux systems; and (c) multifaceted adaptation to slow growth includes adjustment of energy demand for maintenance and preparedness for future nutritional opportunities, i.e. provision of uptake systems and catabolic enzymes for multiple aromatic substrates despite their absence. This broad knowledge base taken together with the recent development of a genetic system will facilitate future functional, biotechnological

  4. Degradation and COD removal of catechol in wastewater using the catalytic ozonation process combined with the cyclic rotating-bed biological reactor.

    PubMed

    Aghapour, Ali Ahmad; Moussavi, Gholamreza; Yaghmaeian, Kamyar

    2015-07-01

    The effect of ozonation catalyzed with MgO/granular activated carbon (MgO/GAC) composite as a pretreatment process on the performance of cyclic rotating-bed biological reactor (CRBR) for the catechol removal from wastewater has been investigated. CRBR with acclimated biomasses could efficiently remove catechol and its related COD from wastewater at organic loading rate (OLR) of 7.82 kg COD/m(3).d (HRT of 9 h). Then, OLR increased to 15.64 kg COD/m(3).d (HRT of 4.5 h) and CRBR failed. Catalytic ozonation process (COP) used as a pre-treatment and could improve the performance of the failed CRBR. The overall removal efficiency of the combined process attained respective steady states of 91% and 79% for degradation and COD removal of catechol. Therefore, the combined process is more effective in degradation and COD removal of catechol; it is also a viable alternative for upgrading industrial wastewater treatment plant.

  5. Coupling of acrylic dyeing wastewater treatment by heterogeneous Fenton oxidation in a continuous stirred tank reactor with biological degradation in a sequential batch reactor.

    PubMed

    Esteves, Bruno M; Rodrigues, Carmen S D; Boaventura, Rui A R; Maldonado-Hódar, F J; Madeira, Luís M

    2016-01-15

    This work deals with the treatment of a recalcitrant effluent, from the dyeing stage of acrylic fibres, by combination of the heterogeneous Fenton's process in a continuous stirred tank reactor (CSTR) with biological degradation in a sequential batch reactor (SBR). Three different catalysts (a commercial Fe/ZSM-5 zeolite and two distinct Fe-containing activated carbons - ACs - prepared by wet impregnation of iron acetate and iron nitrate) were employed on the Fenton's process, and afterwards a parametric study was carried out to determine the effect of the main operating conditions, namely the hydrogen peroxide feed concentration, temperature and contact time. Under the best operating conditions found, using the activated carbon impregnated with iron nitrate, 62.7% of discolouration and 39.9% of total organic carbon (TOC) reduction were achieved, at steady-state. Furthermore, a considerable increase in the effluent's biodegradability was attained (BOD5:COD ratio increased from <0.001 to 0.27 and SOUR - specific oxygen uptake rate - from <0.2 to 11.1 mg O2/(gVSS·h)), alongside a major decrease in its toxicity (from 92.1 to 94.0% of Vibrio fischeri inhibition down to 6.9-9.9%). This allowed the application of the subsequent biological degradation stage. The combination of the two processes provided a treated effluent that clearly complies with the legislated discharge limits. It was also found that the iron leaching from the three catalysts tested was very small in all runs, a crucial factor for the stability and long-term use of such materials.

  6. Quantifying restoration success and recovery in a metal-polluted stream: A 17-year assessment of physicochemical and biological responses

    USGS Publications Warehouse

    Clements, W.H.; Vieira, N.K.M.; Church, S.E.

    2010-01-01

    Evaluating the effectiveness of stream restoration is often challenging because of the lack of pre-treatment data, narrow focus on physicochemical measures and insufficient post-restoration monitoring. Even when these fundamental elements are present, quantifying restoration success is difficult because of the challenges associated with distinguishing treatment effects from seasonal variation, episodic events and long-term climatic changes.2. We report results of one of the most comprehensive and continuous records of physical, chemical and biological data available to assess restoration success for a stream ecosystem in North America. Over a 17 year period we measured seasonal and annual changes in metal concentrations, physicochemical characteristics, macroinvertebrate communities, and brown trout Salmo trutta populations in the Arkansas River, a metal-contaminated stream in Colorado, USA.3. Although we observed significant improvements in water quality after treatment, the effectiveness of restoration varied temporally, spatially and among biological response variables. The fastest recovery was observed at stations where restoration eliminated point sources of metal contamination. Recovery of macroinvertebrates was significantly delayed at some stations because of residual sediment contamination and because extreme seasonal and episodic variation in metal concentrations prevented recolonization by sensitive species. Synthesis and applications. Because recovery trajectories after the removal of a stressor are often complex or nonlinear, long-term studies are necessary to assess restoration success within the context of episodic events and changes in regional climate. The observed variation in recovery among chemical and biological endpoints highlights the importance of developing objective criteria to assess restoration success. Although the rapid response of macroinvertebrates to reduced metal concentrations is encouraging, we have previously demonstrated that

  7. [Microbiological degradation of asymmetrical dimethylhydrazine--a toxic component of rocket fuel].

    PubMed

    Chugunov, V A; Martovetskaia, I I; Mironova, R I; Fomchenkov, V M; Kholodenko, V P

    2000-01-01

    A possibility of microbiological cleaning of water and soil polluted with asymmetric dimethylhydrazine (ADMH), a highly toxic rocket fuel ingredient (RFI), was studied. Several isolates (bacteria, yeast, and micromycetes) capable of utilizing ADMH as the only source of nitrogen, carbon, and energy were isolated from RFI-polluted tundra soil. Acceleration of RFI biodegradation was achieved using a biosorbent that involved cells of the degrader strain immobilized on granulated activated carbon. Biological testing in Escherichia coli and cereals (wheat and barley) demonstrated that biodegradation significantly decreased the integral toxicity of solutions containing ADMH, suggesting its utility for microbiological cleaning of polluted territories.

  8. Analysis of biological factors for determination of air pollution tolerance index of selected plants in Yamuna Nagar, India.

    PubMed

    Sharma, Manju; Panwar, Neeraj; Arora, Pooja; Luhach, Jyoti; Chaudhry, Smita

    2013-05-01

    Air pollution tolerance index (APTI) calculated for various plant species growing in vicinity of three different industrial areas (Paper mill, Sugar mill, Thermal Power Plant) and Yamuna River belt of Yamuna Nagar. Studies were carried out to determine the physiological response of ten plant species. The leaf samples collected from these plant species were used to determine their plant APTI by calculating the ascorbic acid, total chlorophyll, pH, and relative water content for all selected sites. Highest pH, relative water content, ascorbic acid and total chlorophyll was observed in Castor (9.86), Parthenium (96.99%), Ficus benghalensis (14.90 mg g(-1)) and Amaranthus (7.08 mg g(-1)) at Yamuna river, Thermal power plant, Yamuna river and paper mill respectively. It was concluded that out of ten species studied only one species (Ficus benghalensis) showed moderately tolerant response in all selected sites, while other species showed sensitive response. According to observed APTI values, Ficus benghalensis showed the highest value (21.65) at sugar mill followed by thermal power plant (19.38), Paper mill (17.65) and Yamuna River (17.61). The lowest APTI values were reported in Oxalis corniculata (6.42) at Yamuna River belt followed by Malvestrum at sugar mill (7.71).

  9. Fabrication of Ag2O/TiO2 with enhanced photocatalytic performances for dye pollutants degradation by a pH-induced method

    NASA Astrophysics Data System (ADS)

    Ren, Hai-Tao; Yang, Qing

    2017-02-01

    Ag2O/TiO2 composites synthesized in this study were applied into the photocatalytic degradation of methyl orange (MO) under UV and visible light irradiation. X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscope analysis demonstrated that Ag2O nanoparticles were well distributed on the surface of TiO2 and the heterostructure of Ag2O/TiO2 was formed. Compared with the pure TiO2 and Ag2O, the 3% and 50% Ag2O/TiO2 composite displayed much higher photocatalytic activities in MO degradation under UV and visible light irradiation, respectively. The degradation rate constant of 50% composite was 0.01508 min-1 under visible light, which was almost 20.1 and 1.2 times more than that of the pure TiO2 and Ag2O, respectively. Moreover, the formation of Ag(0) on the surface of Ag2O under illumination contributed to the high stability of Ag2O/TiO2 photocatalysts. It was also found that hydroxyl radicals during the photocatalytic process played the predominant role in MO degradation. The enhanced photochemical activities were attributed to the formation of the heterostructure between Ag2O and TiO2, the strong visible light absorption and the high separation efficiency of photogenerated electron-hole pairs resulted from the highly dispersed Ag2O particles.

  10. Advanced electro-Fenton degradation of biologically-treated coking wastewater using anthraquinone cathode and Fe-Y catalyst.

    PubMed

    Li, Haitao; Li, Yuping; Cao, Hongbin; Li, Xingang; Zhang, Yi

    2011-01-01

    The electrocatalytic activity of bare and 2-ethyl anthraquinone-modified graphite felt (2-EAQ/GF) toward oxygen reduction was investigated using a cyclic voltammetry technique in a neutral solution. The prepared cathodes were tested for electrogeneration of H2O2 and electro-Fenton oxidation (EFO) treatment of neutral coking wastewater (CW) after biological process, using a graphite anode and Fezeolite Y catalyst. The results showed that (i) H2O2 yield and current efficiency greatly depended on cathodic potential and materials; (ii) hydroxyl radicals, generated from Fe-zeolite Y-catalyzed H2O2 decomposition, played a great role in EFO treatment, while anodic direct and indirect oxidation was insignificant; (iii) chemical oxygen demand, total organic carbon (TOC) and acute toxicity of wastewater decreased by 40-50, 30-40 and 50-60%, respectively, and biodegradability increased after 1 h of EFO treatment. Due to the free-pH adjustment, EFO presents a potential engineering application for advanced treatment of CW.

  11. Microbial degradation of petroleum hydrocarbons.

    PubMed

    Varjani, Sunita J

    2017-01-01

    Petroleum hydrocarbon pollutants are recalcitrant compounds and are classified as priority pollutants. Cleaning up of these pollutants from environment is a real world problem. Bioremediation has become a major method employed in restoration of petroleum hydrocarbon polluted environments that makes use of natural microbial biodegradation activity. Petroleum hydrocarbons utilizing microorganisms are ubiquitously distributed in environment. They naturally biodegrade pollutants and thereby remove them from the environment. Removal of petroleum hydrocarbon pollutants from environment by applying oleophilic microorganisms (individual isolate/consortium of microorganisms) is ecofriendly and economic. Microbial biodegradation of petroleum hydrocarbon pollutants employs the enzyme catalytic activities of microorganisms to enhance the rate of pollutants degradation. This article provides an overview about bioremediation for petroleum hydrocarbon pollutants. It also includes explanation about hydrocarbon metabolism in microorganisms with a special focus on new insights obtained during past couple of years.

  12. Pollutant Types

    EPA Pesticide Factsheets

    Describes the types of air pollutants, including common or criteria pollutants, and hazardous air pollutants and links to additional information. Also links to resources on other air pollution issues.

  13. Noise Pollution

    MedlinePlus

    ... attention as other types of pollution, such as air pollution, or water pollution. The air around us is ... Air Act Overview Home Progress Cleaning the Air Air Pollution Challenges Requirements and History Role of Science and ...

  14. Water Pollution: Monitoring the Source.

    ERIC Educational Resources Information Center

    Wilkes, James W.

    1980-01-01

    Described is an advanced biology class project involving study of the effects of organic pollution on an aquatic ecosystem from an sewage treatment plant overflow to evaluate the chemical quality and biological activity of the river water. (DS)

  15. Catalytic degradation of recalcitrant pollutants by Fenton-like process using polyacrylonitrile-supported iron (II) phthalocyanine nanofibers: Intermediates and pathway.

    PubMed

    Zhu, Zhexin; Chen, Yi; Gu, Yan; Wu, Fei; Lu, Wangyang; Xu, Tiefeng; Chen, Wenxing

    2016-04-15

    Iron (II) phthalocyanine (FePc) molecules were isolated in polyacrylonitrile (PAN) nanofibers by electrospinning to prevent the formation of dimers and oligomers. Carbamazepine (CBZ) and Rhodamine B (RhB) degradation was investigated during a Fenton-like process with FePc/PAN nanofibers. Classical quenching tests with isopropanol and electron paramagnetic resonance tests with 5,5-dimethyl-pyrroline-oxide as spin-trapping agent were performed to determine the formation of active species during hydrogen peroxide (H2O2) decomposition by FePc/PAN nanofibers. After eight recycles for CBZ degradation over the FePc/PAN nanofibers/H2O2 system, the removal ratios of CBZ remained at 99%. Seven by-products of RhB and twelve intermediates of CBZ were identified using ultra-performance liquid chromatography and high-resolution mass spectrometry. Pathways of CBZ and RhB degradation were proposed based on the identified intermediates. As the reaction proceeded, all CBZ and RhB aromatic nucleus intermediates decreased and were transformed to small acids, but also to potentially toxic epoxide-containing intermediates and acridine, because of the powerful oxidation ability of •OH in the catalytic system.

  16. Protection against LPS-induced cartilage inflammation and degradation provided by a biological extract of Mentha spicata

    PubMed Central

    2010-01-01

    Background A variety of mint [Mentha spicata] has been bred which over-expresses Rosmarinic acid (RA) by approximately 20-fold. RA has demonstrated significant anti-inflammatory activity in vitro and in small rodents; thus it was hypothesized that this plant would demonstrate significant anti-inflammatory activity in vitro. The objectives of this study were: a) to develop an in vitro extraction procedure which mimics digestion and hepatic metabolism, b) to compare anti-inflammatory properties of High-Rosmarinic-Acid Mentha spicata (HRAM) with wild-type control M. spicata (CM), and c) to quantify the relative contributions of RA and three of its hepatic metabolites [ferulic acid (FA), caffeic acid (CA), coumaric acid (CO)] to anti-inflammatory activity of HRAM. Methods HRAM and CM were incubated in simulated gastric and intestinal fluid, liver microsomes (from male rat) and NADPH. Concentrations of RA, CA, CO, and FA in simulated digest of HRAM (HRAMsim) and CM (CMsim) were determined (HPLC) and compared with concentrations in aqueous extracts of HRAM and CM. Cartilage explants (porcine) were cultured with LPS (0 or 3 μg/mL) and test article [HRAMsim (0, 8, 40, 80, 240, or 400 μg/mL), or CMsim (0, 1, 5 or 10 mg/mL), or RA (0.640 μg/mL), or CA (0.384 μg/mL), or CO (0.057 μg/mL) or FA (0.038 μg/mL)] for 96 h. Media samples were analyzed for prostaglandin E2 (PGE2), interleukin 1β (IL-1), glycosaminoglycan (GAG), nitric oxide (NO) and cell viability (differential live-dead cell staining). Results RA concentration of HRAMsim and CMsim was 49.3 and 0.4 μg/mL, respectively. CA, FA and CO were identified in HRAMsim but not in aqueous extract of HRAM. HRAMsim (≥ 8 μg/mL) inhibited LPS-induced PGE2 and NO; HRAMsim (≥ 80 μg/mL) inhibited LPS-induced GAG release. RA inhibited LPS-induced GAG release. No anti-inflammatory or chondroprotective effects of RA metabolites on cartilage explants were identified. Conclusions Our biological extraction procedure produces a

  17. Relation between sources of particulate air pollution and biological effect parameters in samples from four European cities: An exploratory study

    SciTech Connect

    Steerenberg, P.A.; van Amelsvoort, L.; Lovik, M.; Hetland, R.B.; Alberg, T.; Halatek, T.; Bloemen, H.J.T.; Rydzynski, K.; Swaen, G.; Schwarze, P.; Dybing, E.; Cassee, F.R.

    2006-05-15

    Given that there are widely different prevalence rates of respiratory allergies and asthma between the countries of Europe and that exposure to ambient particulate matter (PM) is substantial in urban environments throughout Europe, an EU project entitled 'Respiratory Allergy and Inflammation Due to Ambient Particles' (RAIAP) was set up. The project focused on the role of physical and chemical composition of PM on release of cytokines of cells in vitro, on respiratory inflammation in vivo, and on adjuvant potency in allergy animal models. Coarse (2.5 - 10 {mu}m) and fine (0.15 - 2.5 {mu}m) particles were collected during the spring, summer and winter in Rome ( I), Oslo (N), Lodz (PL), and Amsterdam (NL). Markers within the same model were often well correlated. Markers of inflammation in the in vitro and in vivo models also showed a high degree of correlation. In contrast, correlation between parameters in the different allergy models and between allergy and inflammation markers was generally poor. This suggests that various bioassays are needed to assess the potential hazard of PM. The present study also showed that by clustering chemical constituents of PM based on the overall response pattern in the bioassays, five distinct groups could be identified. The clusters of traffic, industrial combustion and/or incinerators, and combustion of black and brown coal/wood smoke were associated primarily with adjuvant activity for respiratory allergy, whereas clusters of crustal of material and sea spray are predominantly associated with measures for inflammation and acute toxicity. The present study has shown that biological effect of PM can be linked to one or more PM emission sources and that this linkage requires a wide range of bioassays.

  18. Relation between sources of particulate air pollution and biological effect parameters in samples from four European cities: an exploratory study.

    PubMed

    Steerenberg, Peter A; van Amelsvoort, Ludo; Lovik, Martinus; Hetland, Ragna B; Alberg, Torunn; Halatek, Tadeusz; Bloemen, Henk J T; Rydzynski, Konrad; Swaen, Gerard; Schwarze, Per; Dybing, Erik; Cassee, Flemming R

    2006-05-01

    Given that there are widely different prevalence rates of respiratory allergies and asthma between the countries of Europe and that exposure to ambient particulate matter (PM) is substantial in urban environments throughout Europe, an EU project entitled "Respiratory Allergy and Inflammation Due to Ambient Particles" (RAIAP) was set up. The project focused on the role of physical and chemical composition of PM on release of cytokines of cells in vitro, on respiratory inflammation in vivo, and on adjuvant potency in allergy animal models. Coarse (2.5-10 microm) and fine (0.15-2.5 microm) particles were collected during the spring, summer and winter in Rome (I), Oslo (N), Lodz (PL), and Amsterdam (NL). Markers within the same model were often well correlated. Markers of inflammation in the in vitro and in vivo models also showed a high degree of correlation. In contrast, correlation between parameters in the different allergy models and between allergy and inflammation markers was generally poor. This suggests that various bioassays are needed to assess the potential hazard of PM. The present study also showed that by clustering chemical constituents of PM based on the overall response pattern in the bioassays, five distinct groups could be identified. The clusters of traffic, industrial combustion and/or incinerators (TICI), and combustion of black and brown coal/wood smoke (BBCW) were associated primarily with adjuvant activity for respiratory allergy, whereas clusters of crustal of material (CM) and sea spray (SS) are predominantly associated with measures for inflammation and acute toxicity. The cluster of secondary inorganic aerosol and long-range transport aerosol (SIALT) was exclusive associated with systemic allergy. The present study has shown that biological effect of PM can be linked to one or more PM emission sources and that this linkage requires a wide range of bioassays.

  19. Synergistic effect of oxygen vacancy and nitrogen doping on enhancing the photocatalytic activity of Bi2O2CO3 nanosheets with exposed {0 0 1} facets for the degradation of organic pollutants

    NASA Astrophysics Data System (ADS)

    Zhang, Yafei; Zhu, Gangqiang; Hojamberdiev, Mirabbos; Gao, Jianzhi; Hao, Jing; Zhou, Jianping; Liu, Peng

    2016-05-01

    Single-crystalline bare Bi2O2CO3 (BOC) nanosheets with exposed {0 0 1} facets and nitrogen-doped Bi2O2CO3 (NBOC) flower-like microstructures were synthesized by a simple hydrothermal method. The nitrogen-doped Bi2O2CO3 flower-like microstructures with oxygen vacancy (UV-NBOC) were obtained by irradiating the NBOC microstructures with UV light for 2 h in ethanol. The UV-vis diffuse reflectance spectra showed that the NBOC and UV-NBOC nanosheets exhibit an obvious red shift in light absorption band compared with the pure BOC nanosheets. Rhodamine B (RhB) was chosen as a model organic pollutant to verify the influence of oxygen vacancy and nitrogen doping on the photocatalytic activity of Bi2O2CO3 under simulated solar light irradiation. Judging from the kinetics of RhB photodegradation over the synthesized samples, a synergistic effect between oxygen vacancy and nitrogen doping was found with a remarkable increase (more than 10 and 2 times) in the photocatalytic activity of UV-NBOC compared with BOC and NBOC, respectively. Moreover, the UV-NBOC also exhibited an excellent cyclability and superior photocatalytic activity toward degradation of other organic pollutants (methylene blue, Congo red, Bisphenol A) under simulated solar light irradiation.

  20. Degradations and Rearrangement Reactions

    NASA Astrophysics Data System (ADS)

    Zhang, Jianbo

    This section deals with recent reports concerning degradation and rearrangement reactions of free sugars as well as some glycosides. The transformations are classified in chemical and enzymatic ways. In addition, the Maillard reaction will be discussed as an example of degradation and rearrangement transformation and its application in current research in the fields of chemistry and biology.

  1. Immunomodulation by Persistent Organic Pollutants

    EPA Science Inventory

    Persistent organic pollutants (POPs) are widely distnbuted in the environment, are resistant to degradation, and increase in concentration (biomagnify) in the food chain. Concentrations in apical predators may be tens to hundreds of times greater than concentrations in their pref...

  2. In-situ microwave synthesis of graphene-TiO2 nanocomposites with enhanced photocatalytic properties for the degradation of organic pollutants.

    PubMed

    Shanmugam, Mahalingam; Alsalme, Ali; Alghamdi, Abdulaziz; Jayavel, Ramasamy

    2016-10-01

    Graphene-titanium oxide (G-TiO2) nanocomposites were synthesized by a novel surfactant free, environmentally friendly one-port in-situ microwave method. The structure of the nanocomposite was characterized by the X-ray diffraction analysis and the morphology by using scanning electron microscopic and transmission electron microscopic images. The functional groups and carbon band structures were identified using FTIR and Raman spectral analysis. TiO2 nanoparticles in the size range of 5-10nm were distributed on the graphene sheets. The surface area of pure TiO2 and G-TiO2 nanocomposite was measured to be 20.11 and 173.76m(2)/g respectively. The pore volume and pore size of TiO2 were 0.018cm(3)/g and 1.5266nm respectively. G-TiO2 composite possesses higher pore volume (0.259cm(3)/g) and pore size 3.2075nm. The binding states of C, O and Ti of nanocomposite were analyzed by X-ray photoelectron spectroscopy, which confirmed the chemical bonding between graphene-TiO2. The photocatalytic activity of pure TiO2 and G-TiO2 nanocomposite was studied under UV and visible light irradiation sources with methylene blue dye. It has been observed that the degradation was faster in G-TiO2 nanocomposite than pure TiO2 nanoparticles. The rate constant and half life time were calculated from the kinetic studies of the degradation. The highest degradation efficiency of 97% was achieved in UV light and 96% for visible light irradiation with G-TiO2 as a catalyst. The studies reveal that G-TiO2 nanocomposite can be an effective catalyst for industrial waste water treatment.

  3. Cu(2)ZnSnS(4)-Pt and Cu(2)ZnSnS(4)-Au heterostructured nanoparticles for photocatalytic water splitting and pollutant degradation.

    PubMed

    Yu, Xuelian; Shavel, Alexey; An, Xiaoqiang; Luo, Zhishan; Ibáñez, Maria; Cabot, Andreu

    2014-07-02

    Cu2ZnSnS4, based on abundant and environmental friendly elements and with a direct band gap of 1.5 eV, is a main candidate material for solar energy conversion through both photovoltaics and photocatalysis. We detail here the synthesis of quasi-spherical Cu2ZnSnS4 nanoparticles with unprecedented narrow size distributions. We further detail their use as seeds to produce CZTS-Au and CZTS-Pt heterostructured nanoparticles. Such heterostructured nanoparticles are shown to have excellent photocatalytic properties toward degradation of Rhodamine B and hydrogen generation by water splitting.

  4. Field assessment of the mid winter mass kills of trophic fishes at Mariotteya stream, Egypt: chemical and biological pollution synergistic model.

    PubMed

    Eissa, A E; Tharwat, N A; Zaki, M M

    2013-01-01

    Pathogenic Candida albicans was isolated from water and fish samples collected during an emergent event of mass mortalities among the juvenile Nile tilapia (Oreochromis niloticus), Sharp toothed catfish (Clarias gariepinus) along the stream of Mariotteya drainage. Investigations indicated that fish mortalities were confined to the area of Shubramant and Aboul Noumros (North to Sakara 7 drainage). C. albicans was isolated from the lesions associated with multiple skin ulcers in both Nile tilapia juveniles and Sharp toothed catfish. Assessment of the field and laboratory data has indicated that Mariotteya environmental disaster was a multifactorial problem. The fish mass kills were initially flared up through the dumping of the improperly treated nasty organic and inorganic chemicals from Elhawamdia sugar factory and municipal sewage. The physical stagnation of the stream, high levels of ammonia, phenol and polycyclic aromatic hydrocarbons (PAHs) and low levels of dissolved oxygen (DO) were all incriminated as the initial stimulus behind biological invasion of pathogenic bacteria (Pseudomonas fluorescence) and yeast (C. albicans). Pathologically, fishes were dying from both respiratory and osmoregulatory failure induced by the severe damage of both gills and skin. It has been implied that such environmental pollutants have direct damaging effects on gills, skin and fins with consequent suppression of the skin's natural innate components. The adversely confronted immunological barriers were further exacerbated by the possible synergistic interactions of P. fluorescence dermotropic toxins followed by the secondary invasion of the pathogenic C. albicans.

  5. Considering the Specific Impact of Harsh Conditions and Oil Weathering on Diversity, Adaptation, and Activity of Hydrocarbon-Degrading Bacteria in Strategies of Bioremediation of Harsh Oily-Polluted Soils

    PubMed Central

    Al Disi, Zulfa; Jaoua, Samir; Al-Thani, Dhabia; Al-Meer, Saeed

    2017-01-01

    Weathering processes change properties and composition of spilled oil, representing the main reason of failure of bioaugmentation strategies. Our purpose was to investigate the metabolic adaptation of hydrocarbon-degrading bacteria at harsh conditions to be considered to overcome the limitations of bioaugmentation strategies at harsh conditions. Polluted soils, exposed for prolonged periods to weathered oil in harsh soils and weather conditions, were used. Two types of enrichment cultures were employed using 5% and 10% oil or diesel as sole carbon sources with varying the mineral nitrogen sources and C/N ratios. The most effective isolates were obtained based on growth, tolerance to toxicity, and removal efficiency of diesel hydrocarbons. Activities of the newly isolated bacteria, in relation to the microenvironment from where they were isoalted and their interaction with the weathered oil, showed individual specific ability to adapt when exposed to such factors, to acquire metabolic potentialities. Among 39 isolates, ten identified ones by 16S rDNA genes similarities, including special two Pseudomonas isolates and one Citrobacter isolate, showed particularity of shifting hydrocarbon-degrading ability from short chain n-alkanes (n-C12–n-C16) to longer chain n-alkanes (n-C21–n-C25) and vice versa by alternating nitrogen source compositions and C/N ratios. This is shown for the first time. PMID:28243605

  6. Biology Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1982

    1982-01-01

    Presents procedures, exercises, demonstrations, and information on a variety of biology topics including labeling systems, biological indicators of stream pollution, growth of lichens, reproductive capacity of bulbous buttercups, a straw balance to measure transpiration, interaction of fungi, osmosis, and nitrogen fixation and crop production. (DC)

  7. Ultrasonic-assisted one-pot preparation of ZnO/Ag3VO4 nanocomposites for efficiently degradation of organic pollutants under visible-light irradiation

    NASA Astrophysics Data System (ADS)

    Kiantazh, Fariba; Habibi-Yangjeh, Aziz

    2015-11-01

    We report a facile ultrasonic-assisted one-pot method for preparation of ZnO/Ag3VO4 nanocomposites with different mole fractions of silver vanadate. The preparation method has considerable merits such as short preparation time, large-scale, and one-pot strategy. The resultant samples were fairly characterized by means of XRD, EDX, SEM, TEM, UV-vis DRS, FT-IR, and PL techniques. Visible-light activity of the resultant samples was investigated by degradation of rhodamine B (RhB), methylene blue (MB), and methyl orange (MO). Among the prepared nanocomposites, the ZnO/Ag3VO4 nanocomposite with 0.073 mole fraction of Ag3VO4 exhibited the best activity and excessive amount of Ag3VO4 resulted in decrease of the activity. Photocatalytic activity of this nanocomposite under visible-light irradiation is about 21, 56, and 2.8-fold higher than that of the ZnO sample in degradation of RhB, MB, and MO, respectively. The highly enhanced activity of the nanocomposite was attributed to greater generation of electron-hole pairs, due to photosensitizing role of Ag3VO4 under visible-light irradiation, and efficiently separation of the photogenerated electron-hole pairs, due to formation of n-n heterojunction between the counterparts. Furthermore, it was revealed that the photocatalytic activity largely depends on ultrasonic irradiation time, calcination temperature, and scavengers of the reactive species.

  8. Novel AgI-decorated β-Bi₂O₃ nanosheet heterostructured Z-scheme photocatalysts for efficient degradation of organic pollutants with enhanced performance.

    PubMed

    Zhang, Zhengyuan; Jiang, Deli; Xing, Chaosheng; Chen, Linlin; Chen, Min; He, Minqiang

    2015-07-07

    The low photocatalytic activity of single semiconductor photocatalysts mainly originates from their fast recombination of photogenerated electron-hole pairs. Constructing nanosheet-based composite photocatalysts is an effective way to enhance the charge separation efficiency of photogenerated electron-hole pairs. In this work, AgI-decorated β-Bi2O3 nanosheet heterostructured photocatalysts were prepared by a facile method. The as-obtained AgI/β-Bi2O3 heterostructures exhibited enhanced visible-light-driven photocatalytic activity towards the degradation of methyl orange (MO) and tetracycline hydrochloride (TC) in aqueous solution. The optimum photocatalytic activity of 20%-AgI/β-Bi2O3 for the degradation of MO was about 4.1 and 6.2 times higher than that of AgI and β-Bi2O3. The photocatalytic activity enhancement of AgI/β-Bi2O3 heterostructures could be ascribed to the formation of a Z-scheme system, which results in the efficient space separation of photo-induced charge carriers.

  9. Synthesis and characterization of novel plasmonic Ag/AgX-CNTs (X = Cl, Br, I) nanocomposite photocatalysts and synergetic degradation of organic pollutant under visible light.

    PubMed

    Shi, Huixian; Chen, Jiangyao; Li, Guiying; Nie, Xin; Zhao, Huijun; Wong, Po-Keung; An, Taicheng

    2013-08-14

    A series of novel well-defined Ag/AgX (X = Cl, Br, I) loaded carbon nanotubes (CNTs) composite photocatalysts (Ag/AgX-CNTs) were fabricated for the first time via a facile ultrasonic assistant deposition-precipitation method at the room temperature (25 ± 1 °C). X-ray diffraction, X-ray photoelectron spectroscopy, nitrogen adsorption-desorption analysis, scanning electron microscopy, and ultraviolet-visible light absorption spectra analysis were used to characterize the structure, morphology, and optical properties of the as-prepared photocatalysts. Results confirmed the existence of the direct interfacial contact between Ag/AgX nanoparticles and CNTs, and Ag/AgX-CNTs nanocomposites exhibit superior absorbance in the visible light (VL) region owing to the surface plasmon resonance (SPR) of Ag nanoparticles. The fabricated composite photocatalysts were employed to remove 2,4,6-tribromophenol (TBP) in aqueous phase. A remarkably enhanced VL photocatalytic degradation efficiency of Ag/AgX-CNTs nanocomposites was observed when compared to that of pure AgX or CNTs. The photocatalytic activity enhancement of Ag/AgX-CNTs was due to the effective electron transfer from photoexcited AgX and plasmon-excited Ag(0) nanoparticles to CNTs. This can effectively decrease the recombination of electron-hole pairs, lead to a prolonged lifetime of the photoholes that promotes the degradation efficiency.

  10. Synthesis of surface molecular imprinted TiO2/graphene photocatalyst and its highly efficient photocatalytic degradation of target pollutant under visible light irradiation

    NASA Astrophysics Data System (ADS)

    Lai, Cui; Wang, Man-Man; Zeng, Guang-Ming; Liu, Yun-Guo; Huang, Dan-Lian; Zhang, Chen; Wang, Rong-Zhong; Xu, Piao; Cheng, Min; Huang, Chao; Wu, Hai-Peng; Qin, Lei

    2016-12-01

    The molecular imprinted TiO2/graphene photocatalyst (MIP-TiO2/GR) was successfully prepared with bisphenol A (BPA) as the template molecule (target pollutant) and o-phenylenediamine (OPDA) as functional monomers by the surface molecular imprinting method. The combination between BPA and OPDA led to the formation of the precursor, and the subsequent polymerization of OPDA initiated by ultraviolet radiation can ensure the realization of MIP-TiO2/GR. The samples were characterized by SEM, EDS, XRD, BET, UV-vis DRS and Zeta potential. In addition, adsorption capacities, adsorption selectivity and visible light photocatalytic performances of MIP-TiO2/GR and non-imprinted TiO2/graphene (NIP-TiO2/GR) were evaluated. Moreover, the effects of pH and initial BPA concentration on removal efficiency of BPA were also investigated. The results showed that MIP-TiO2/GR exhibited better adsorption capacity and adsorption selectivity towards the template molecule compared to NIP-TiO2/GR due to the imprinted cavities on the surface of MIP-TiO2/GR. Moreover, the photocatalytic activity of MIP-TiO2/GR toward the target molecules was stronger than that of NIP-TiO2/GR as a result of large adsorption capacity to target molecules and narrow band gap energy on MIP-TiO2/GR. Therefore, modifying the photocatalyst by the surface molecular imprinting is a promising method to improve the molecule recognition and photocatalytic efficiency of photocatalyst for target pollutant.

  11. Pollution of the marine environment

    SciTech Connect

    Malins, D.C.

    1980-01-01

    An interdisciplinary approach to identifying chemical pollution in the marine environment and assessing the effects of such pollution on living marine resources is described. Such a study requires knowing: what pollutants organisms are exposed to, which pollutants are accumulated; the fate of pollutants taken up by organisms, and biological changes caused by the pollutants. Analytical limitations of such studies are noted. Examples of specific interdisciplinary laboratory and field investigations are presented, for instance, the finding of liver tumors in flatfish that accumulated sediment-bound naphthalene.

  12. Coupling of Nanocrystalline Anatase TiO2 to Porous Nanosized LaFeO3 for Efficient Visible-Light Photocatalytic Degradation of Pollutants

    PubMed Central

    Humayun, Muhammad; Li, Zhijun; Sun, Liqun; Zhang, Xuliang; Raziq, Fazal; Zada, Amir; Qu, Yang; Jing, Liqiang

    2016-01-01

    In this work we have successfully fabricated nanocrystalline anatase TiO2/perovskite-type porous nanosized LaFeO3 (T/P-LFO) nanocomposites using a simple wet chemical method. It is clearly demonstrated by means of atmosphere-controlled steady-state surface photovoltage spectroscopy (SPS) responses, photoluminescence spectra, and fluorescence spectra related to the formed OH− radical amount that the photogenerated charge carriers in the resultant T/P-LFO nanocomposites with a proper mole ratio percentage of TiO2 display much higher separation in comparison to the P-LFO alone. This is highly responsible for the improved visible-light activities of T/P-LFO nanocomposites for photocatalytic degradation of gas-phase acetaldehyde and liquid-phase phenol. This work will provide a feasible route to synthesize visible-light responsive nano-photocatalysts for efficient solar energy utilization.

  13. NON-POINT SOURCE POLLUTION

    EPA Science Inventory

    Non-point source pollution is a diffuse source that is difficult to measure and is highly variable due to different rain patterns and other climatic conditions. In many areas, however, non-point source pollution is the greatest source of water quality degradation. Presently, stat...

  14. Visible light-driven photocatalytic degradation of the organic pollutant methylene blue with hybrid palladium-fluorine-doped titanium oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Lázaro-Navas, Sonia; Prashar, Sanjiv; Fajardo, Mariano; Gómez-Ruiz, Santiago

    2015-02-01

    The synthesis of mesoporous aggregates of titanium oxide nanoparticles (F0) is described using a very cheap and simple synthetic protocol. This consists of the reaction of titanium tetraisopropoxide and a solution of HNO3 in water (pH 2.0) and subsequent filtration. In addition, fluorine-doped titanium oxides (F1, F2, F5 and F10) were synthesized using the same method, adding increasing amounts of NaF to the reaction mixture (avoiding the use of expensive reagents such as NH4F or trifluoroacetic acid). The resulting materials were calcined at different temperatures (500, 600 and 650 °C) giving particles sized between 10 and 20 nm. Furthermore, a hybrid F-doped TiO2 with supported palladium nanoparticles of ca. 20 nm (F5-500-Pd1) was synthesized by grafting an organometallic palladium(II) salt namely [Pd(cod)Cl2] (cod = 1,5-cyclooctadiene). Photocatalytic studies of the degradation of methylene blue (MB) were carried out under UV light using all the synthesized material (non-doped an F-doped TiO2), observing that the increase in the quantity of fluorine has a positive effect on the photocatalytic activity. F5-500 is apparently the material which has the most convenient structural properties (in terms of surface area and anatase/rutile ratio) and thus a higher photocatalytic activity. The hybrid material F-doped TiO2-Pd nanoparticles (F5-500-Pd1) has a lower band gap value than F5-500, and thus photocatalytic degradation of MB under LED visible light was achieved using F5-500-Pd1 as photocatalyst.

  15. A visible-light-driven core-shell like Ag2S@Ag2CO3 composite photocatalyst with high performance in pollutants degradation.

    PubMed

    Yu, Changlin; Wei, Longfu; Zhou, Wanqin; Dionysiou, Dionysios D; Zhu, Lihua; Shu, Qing; Liu, Hong

    2016-08-01

    A series of Ag2S-Ag2CO3 (4%, 8%, 16%, 32% and 40% Ag2S), Ag2CO3@Ag2S (32%Ag2S) and Ag2S@Ag2CO3 (32%Ag2S) composite photocatalysts were fabricated by coprecipitation or successive precipitation reaction. The obtained catalysts were analyzed by N2 physical adsorption, powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, UV-vis diffuse reflectance spectroscopy and photocurrent test. Under visible light irradiation, the influences of Ag2S content and core-shell property on photocatalytic activity and stability were evaluated in studies focused on the degradation of methyl orange (MO) dye, phenol, and bisphenol A. Results showed that excellent photocatalytic performance was obtained over Ag2S/Ag2CO3 composite photocatalysts with respect to Ag2S and Ag2CO3. With optimal content of Ag2S (32 wt%), the Ag2S-Ag2CO3 showed the highest photocatalytic degradation efficiency. Moreover, the structured property of Ag2S/Ag2CO3 greatly influenced the activity. Compared with Ag2S-Ag2CO3 and Ag2CO3@Ag2S, core-shell like Ag2S@Ag2CO3 demonstrated the highest activity and stability. The main reason for the boosting of photocatalytic performance was due to the formation of Ag2S/Ag2CO3 well contacted interface and unique electron structures. Ag2S/Ag2CO3 interface could significantly increase the separation efficiency of the photo-generated electrons (e(-)) and holes (h(+)), and production of OH radicals. More importantly, the low solubility of Ag2S shell could effectively protect the core of Ag2CO3, which further guarantees the stability of Ag2CO3.

  16. Measuring River Pollution

    ERIC Educational Resources Information Center

    Ayyavoo, Gabriel

    2004-01-01

    The Don River watershed is located within Canada's most highly urbanized area--metropolitan Toronto. Many residential and commercial uses, including alterations to the river's course with bridges, have had a significant impact on the Don's fauna and flora. Pollutants have degraded the river's water quality, a situation exacerbated by the…

  17. Water Pollution

    ERIC Educational Resources Information Center

    Bowen, H. J. M.

    1975-01-01

    Deals with water pollution in the following categories: a global view, self purification, local pollution, difficulties in chemical analysis, and remedies for water pollution. Emphasizes the extent to which man's activities have modified the cycles of certain elements. (GS)

  18. Air Pollution

    MedlinePlus

    Air pollution is a mixture of solid particles and gases in the air. Car emissions, chemicals from factories, ... Ozone, a gas, is a major part of air pollution in cities. When ozone forms air pollution, it's ...

  19. 3D TiO{sub 2} submicrostructures decorated by silver nanoparticles as SERS substrate for organic pollutants detection and degradation

    SciTech Connect

    Chen, Jianjun; Su, Huilan; You, Xueling; Gao, Jing; Lau, Woon Ming; Zhang, Di

    2014-01-01

    Graphical abstract: - Highlights: • Contrive a multifunctional SERS substrate with 3D sub-micrometer structure and multicomponent. • The blue wing of butterfly (Euploea mulciber) is used as template for Ag/TiO{sub 2} nanocomposites. • The 3D submicrostructures Ag/TiO{sub 2} presents superior SERS effect and photocatalytic activity. • Pave a facile route to prepare multifunctional material by utilizing smart structural designs in nature. - Abstract: The blue wing of butterfly Euploea mulciber is used as a template to generate Ag/TiO{sub 2} nanocomposites. Thereinto, Ag nanoparticles are deposited uniformly onto TiO{sub 2} substrate with three dimensional (3D) submicrometer structures. This unique 3D sub-micrometer structures featured with ridges, ribs and struts can provide a large number of active “hot spots” for enhanced Raman signal. Meanwhile, depositing Ag onto the TiO{sub 2} surface can greatly boost its SERS effect and photocatalytic activity by bringing additional electrons into the molecules and inhibiting electrons–holes recombination. Thus, the as-prepared 3D Ag/TiO{sub 2} submicrostructures can not only offer sensitive and reproducible SERS signals, but also present superior photocatalytic activity, which can be utilized to detect and eliminate organic pollutants.

  20. Synthesis of hectorite-TiO2 and kaolinite-TiO2 nanocomposites with photocatalytic activity for the degradation of model air pollutants

    SciTech Connect

    Destaillats, Hugo; Kibanova, D.; Trejo, M.; Destaillats, H.; Cervini-Silva, J.

    2008-03-01

    We studied the synthesis and photocatalytic activity of small-sized TiO{sub 2} supported on hectorite and kaolinite. Deposition of TiO{sub 2} on the clay mineral surface was conducted by using a sol-gel method with titanium isopropoxide as precursor. Anatase TiO{sub 2} particles formation was achieved by hydrothermal treatment at 180 C. Material characterization was conducted using XRD, SEM, XPS, ICP-OES, BET and porosimetry analysis. Efficiency in synthesizing clay-TiO{sub 2} composites depended strongly on the clay mineral structure. Incorporation of anatase in hectorite, an expandable clay mineral, was found to be very significant (> 36 wt.% Ti) and to be followed by important structural changes at the clay mineral surface. Instead, no major structural modifications of the clay were observed for kaolinite-TiO{sub 2}, as compared with the untreated material. Photocatalytic performance of clay-TiO{sub 2} composites was evaluated with ATR-FTIR following the oxidation of adsorbed toluene and d-limonene, two model air pollutants. In either case, the photocatalytic removal efficiency of these hydrophobic substrates by the synthesized clay-TiO{sub 2} composites was comparable to that observed using pure commercial TiO{sub 2} (Degussa P25).

  1. Bioaccumulation Potential Of Air Contaminants: Combining Biological Allometry, Chemical Equilibrium And Mass-Balances To Predict Accumulation Of Air Pollutants In Various Mammals

    SciTech Connect

    Veltman, Karin; McKone, Thomas E.; Huijbregts, Mark A.J.; Hendriks, A. Jan

    2009-03-01

    In the present study we develop and test a uniform model intended for single compartment analysis in the context of human and environmental risk assessment of airborne contaminants. The new aspects of the model are the integration of biological allometry with fugacity-based mass-balance theory to describe exchange of contaminants with air. The developed model is applicable to various mammalian species and a range of chemicals, while requiring few and typically well-known input parameters, such as the adult mass and composition of the species, and the octanol-water and air-water partition coefficient of the chemical. Accumulation of organic chemicals is typically considered to be a function of the chemical affinity forlipid components in tissues. Here, we use a generic description of chemical affinity for neutral and polar lipids and proteins to estimate blood-air partition coefficients (Kba) and tissue-air partition coefficients (Kta) for various mammals. This provides a more accurate prediction of blood-air partition coefficients, as proteins make up a large fraction of total blood components. The results show that 75percent of the modeled inhalation and exhalation rate constants are within a factor of 2 from independent empirical values for humans, rats and mice, and 87percent of the predicted blood-air partition coefficients are within a factor of 5 from empirical data. At steady-state, the bioaccumulation potential of air pollutants is shown to be mainly a function of the tissue-air partition coefficient and the biotransformation capacity of the species and depends weakly on the ventilation rate and the cardiac output of mammals.

  2. Ultrasonic-assisted preparation of plasmonic ZnO/Ag/Ag2WO4 nanocomposites with high visible-light photocatalytic performance for degradation of organic pollutants.

    PubMed

    Pirhashemi, Mahsa; Habibi-Yangjeh, Aziz

    2017-04-01

    In this work, plasmonic ternary ZnO/Ag/Ag2WO4 nanocomposites as efficient visible-light-driven photocatalysts prepared by a facile ultrasonic-irradiation method. The as-prepared samples were characterized by XRD, SEM, TEM, EDX, XPS, UV-vis DRS, FT-IR, and PL techniques. The photocatalytic performance of the prepared ZnO/Ag/Ag2WO4 nanocomposites were evaluated by photodegradations of rhodamine B, methylene blue, methyl orange, and fuchsine under visible-light irradiation. The optimal nanocomposite with 15wt% of Ag/Ag2WO4 to ZnO showed the highest photocatalytic activity for RhB degradation, which is about 95 and 19 times higher than those of the Ag/Ag2WO4 and ZnO samples, respectively. The highly enhanced activity of the ZnO/Ag/Ag2WO4 (15%) nanocomposite was attributed to the surface plasmon resonance effect of metallic silver and the formation of heterojunctions between the counterparts, which effectively suppresses recombination of the photogenerated charge carriers. Lastly, the plasmon-enhanced photocatalytic mechanism associated with the ZnO/Ag/Ag2WO4 nanocomposites was discussed.

  3. Preparation of flower-like TiO2 sphere/reduced graphene oxide composites for photocatalytic degradation of organic pollutants

    NASA Astrophysics Data System (ADS)

    Kim, Tae-Woong; Park, Mira; Kim, Hak Yong; Park, Soo-Jin

    2016-07-01

    In this study, novel flower-like TiO2 sphere (FTS)/reduced graphene oxide (rGO) composites (FTS-G) were synthesized via a hydrothermal method. The photocatalytic performance of the FTS-G composites was evaluated through the photodegradation of rhodamine B (Rh B) and trichloroethylene (TCE) under simulated solar light irradiation. The rGO to FTS ratio in the composites significantly affected photocatalytic activity. The photocatalytic activities of FTS-Gs in the degradation of Rh B and TCE were superior to that of pure FTS. Of all the FTS-G composites tested, FTS-G with 1 wt% rGO (FTS-G-1) had the greatest photocatalytic activity, while FTS-G composites with rGO contents over 1 wt% had lower photocatalytic activities. Additionally, it is expected that the synthesis of FTS with a high specific surface area and well-developed pore structure and simultaneous conversion of GO to graphene-like rGO without the use of strong reducing agents could be a promising strategy to prepare other carbon-based flower-like TiO2 sphere composite photocatalysts.

  4. Preparation of flower-like TiO{sub 2} sphere/reduced graphene oxide composites for photocatalytic degradation of organic pollutants

    SciTech Connect

    Kim, Tae-Woong; Park, Mira; Kim, Hak Yong; Park, Soo-Jin

    2016-07-15

    In this study, novel flower-like TiO{sub 2} sphere (FTS)/reduced graphene oxide (rGO) composites (FTS-G) were synthesized via a hydrothermal method. The photocatalytic performance of the FTS-G composites was evaluated through the photodegradation of rhodamine B (Rh B) and trichloroethylene (TCE) under simulated solar light irradiation. The rGO to FTS ratio in the composites significantly affected photocatalytic activity. The photocatalytic activities of FTS-Gs in the degradation of Rh B and TCE were superior to that of pure FTS. Of all the FTS-G composites tested, FTS-G with 1 wt% rGO (FTS-G-1) had the greatest photocatalytic activity, while FTS-G composites with rGO contents over 1 wt% had lower photocatalytic activities. Additionally, it is expected that the synthesis of FTS with a high specific surface area and well-developed pore structure and simultaneous conversion of GO to graphene-like rGO without the use of strong reducing agents could be a promising strategy to prepare other carbon-based flower-like TiO{sub 2} sphere composite photocatalysts. - Graphical abstract: Schematic illustration of high photocatalytic activity for FTS-G composites. Display Omitted.

  5. Monitoring of Gasoline-ethanol Degradation In Undisturbed Soil

    NASA Astrophysics Data System (ADS)

    Österreicher-Cunha, P.; Nunes, C. M. F.; Vargas, E. A.; Guimarães, J. R. D.; Costa, A.

    Environmental contamination problems are greatly emphasised nowadays because of the direct threat they represent for human health. Traditional remediation methods fre- quently present low efficiency and high costs; therefore, biological treatment is being considered as an accessible and efficient alternative for soil and water remediation. Bioventing, commonly used to remediate petroleum hydrocarbon spills, stimulates the degradation capacity of indigenous microorganisms by providing better subsur- face oxygenation. In Brazil, gasoline and ethanol are mixed (78:22 v/v); some authors indicate that despite gasoline high degradability, its degradation in subsurface is hin- dered by the presence of much more rapidly degrading ethanol. Contaminant distribu- tion and degradation in the subsurface can be monitored by several physical, chemical and microbiological methodologies. This study aims to evaluate and follow the degra- dation of a gasoline-ethanol mixture in a residual undisturbed tropical soil from Rio de Janeiro. Bioventing was used to enhance microbial degradation. Shifts in bacte- rial culturable populations due to contamination and treatment effects were followed by conventional microbiology methods. Ground Penetrating Radar (GPR) measure- ments, which consist of the emission of electro-magnetic waves into the soil, yield a visualisation of contaminant degradation because of changes in soil conductivity due to microbial action on the pollutants. Chemical analyses will measure contaminant residue in soil. Our results disclosed contamination impact as well as bioventing stim- ulation on soil culturable heterotrophic bacterial populations. This multidisciplinary approach allows for a wider evaluation of processes occurring in soil.

  6. [Immobilization of Estrogen-degrading Bacteria to Remove the 17β-estradiol and Diethylstilbestrol from Polluted Water and Cow Dung].

    PubMed

    Li, Xin; Ling, Wan-ting; Liu, Jing-xian; Sun, Min-xia; Gao, Yan-zheng; Liu, Juan

    2015-07-01

    Estradiol (E2) and diethylstilbestrol (DES) can be enriched in sewage and cow dung, posing serious threats to human and ecological health. Strain Rhodococcus sp. JX-2 and strain Serratia sp. S, which could degrade 17β-estradiol and diethylstilbestrol, respectively, were immobilized by alginate and then added into sewage and cow dung to remove E2 and DES. The immobilization was determined by orthogonal experiment, and the removal of E2 and DES from sewage and cow dung was compared between treatments of immobilized bacteria, free bacteria and control without bacteria. The influencing factors including inoculation amount, pH value, moisture content, turning time on the removal of E2 and DES were investigated. The optimal conditions of JX-2 and S immobilization were as follows: Strain JX-2: strain S (V/V) 1: 1, alginate concentration 5%, calcium chloride concentration 4%, bacteria-cement ratio 1 : 2. The immobilized strains removed 99. 42% and 84. 59% of the 2 mg.L-1 E2 and DES under laboratory conditions, respectively. The optimal conditions for E2 and DES removal from water by the immobilized strains were as follows: 300 g.L-1 inoculation volume of immobilized strains and pH 5. 0-6. 0. Immobilized bacteria could completely remove DES and remove 95. 85% of E2 from water. The optimal conditions for E2 and DES removal from cow dung by the immobilized strains were: inoculation volume 600 g.kg-1, moisture content 70% and pile turning time 12 h. The immobilized bacteria could completely remove E2 and remove 97. 41% of DES from cow dung.

  7. Marine pollution data services

    SciTech Connect

    Abram, R.J.

    1980-09-01

    The Nat'l Oceanographic Data Center of NOAA is responsible for building and maintaining a global data base on the physical, chemical, and biological properties of world oceans. Data relevant to pollution studies, primarily those associated with oil spills, are included. Inventory and retrieval systems utilized are described. International programs provide extensive data for this marine pollution information service. (1 diagram, 1 map, 2 photos)

  8. Decision criteria for the selection of wet oxidation and conventional biological treatment.

    PubMed

    Collado, Sergio; Laca, Adriana; Diaz, Mario

    2012-07-15

    The suitability of wet oxidation or biological treatments for the degradation of industrial wastewaters is here discussed. Advantages of these operations, either singly or in combination, are discussed on the basis of previous experimental results from laboratory and industry. Decision diagrams for the selection of conventional biological treatment, wet oxidation or a combination of both techniques are suggested according to the type of pollutant, its concentration and the wastewater flow rate.

  9. Pollution Probe.

    ERIC Educational Resources Information Center

    Chant, Donald A.

    This book is written as a statement of concern about pollution by members of Pollution Probe, a citizens' anti-pollution group in Canada. Its purpose is to create public awareness and pressure for the eventual solution to pollution problems. The need for effective government policies to control the population explosion, conserve natural resources,…

  10. Biology of Pseudomonas stutzeri

    PubMed Central

    Lalucat, Jorge; Bennasar, Antoni; Bosch, Rafael; García-Valdés, Elena; Palleroni, Norberto J.

    2006-01-01

    Pseudomonas stutzeri is a nonfluorescent denitrifying bacterium widely distributed in the environment, and it has also been isolated as an opportunistic pathogen from humans. Over the past 15 years, much progress has been made in elucidating the taxonomy of this diverse taxonomical group, demonstrating the clonality of its populations. The species has received much attention because of its particular metabolic properties: it has been proposed as a model organism for denitrification studies; many strains have natural transformation properties, making it relevant for study of the transfer of genes in the environment; several strains are able to fix dinitrogen; and others participate in the degradation of pollutants or interact with toxic metals. This review considers the history of the discovery, nomenclatural changes, and early studies, together with the relevant biological and ecological properties, of P. stutzeri. PMID:16760312

  11. Photocatalytic activities of coke carbon/g-C3N4 and Bi metal/Bi mixed oxides/g-C3N4 nanohybrids for the degradation of pollutants in wastewater

    PubMed Central

    Sierra, Marta; Borges, Emma; Esparza, Pedro; Méndez-Ramos, Jorge; Martín-Gil, Jesús; Martín-Ramos, Pablo

    2016-01-01

    Abstract Different g-C3N4 composite systems (coke carbon/g-C3N4, Bi/Bi2WO6/g-C3N4 and Bi/Bi2MoO6/g-C3N4) have been assessed as photocatalysts for wastewater pollutants removal. The coke carbon/g-C3N4 hybrid, produced by thermal treatment at 550 °C of a composite made from melamine cyanurate and coke, only showed activity under UV-light irradiation. On the other hand, inorganic Bi spheres/Bi mixed oxides/g-C3N4 nanohybrids (Bi/Bi2WO6/g-C3N4 and Bi/Bi2MoO6/g-C3N4 composites), produced by thermal reduction of Bi2WO6 or Bi2MoO6 by g-C3N4, exhibited a remarkable red-shift, up to 620 nm, and allowed the visible-light driven degradation of the contaminant, albeit in combination with some adsorption. PMID:27877912

  12. Photocatalytic activities of coke carbon/g-C3N4 and Bi metal/Bi mixed oxides/g-C3N4 nanohybrids for the degradation of pollutants in wastewater.

    PubMed

    Sierra, Marta; Borges, Emma; Esparza, Pedro; Méndez-Ramos, Jorge; Martín-Gil, Jesús; Martín-Ramos, Pablo

    2016-01-01

    Different g-C3N4 composite systems (coke carbon/g-C3N4, Bi/Bi2WO6/g-C3N4 and Bi/Bi2MoO6/g-C3N4) have been assessed as photocatalysts for wastewater pollutants removal. The coke carbon/g-C3N4 hybrid, produced by thermal treatment at 550 °C of a composite made from melamine cyanurate and coke, only showed activity under UV-light irradiation. On the other hand, inorganic Bi spheres/Bi mixed oxides/g-C3N4 nanohybrids (Bi/Bi2WO6/g-C3N4 and Bi/Bi2MoO6/g-C3N4 composites), produced by thermal reduction of Bi2WO6 or Bi2MoO6 by g-C3N4, exhibited a remarkable red-shift, up to 620 nm, and allowed the visible-light driven degradation of the contaminant, albeit in combination with some adsorption.

  13. Effect of toluene as gaseous cosubstrate in bioremediation of hydrocarbon-polluted soil.

    PubMed

    Ortiz, Irmene; Velasco, Antonio; Revah, Sergio

    2006-04-17

    The stimulation of the microbial population by a more bioavailable supplementary carbon source and by a surfactant pretreatment was studied in petroleum hydrocarbon-polluted soils bioremediation. Two types of soils were used, Soil A which had been recently polluted and the aged Soil B. They contained 52.4 and 50.4 g of total petroleum hydrocarbons per kg of dry soil, respectively. The effect of passing a continuous small stream of air containing a low concentration of gaseous toluene through packed 0.5 l (Ø=5.5 cm) columns was studied. For Soil A, after 62 days the THPs degradation was 28% higher in the toluene treated columns than in controls. In aged Soil B the effect of toluene was not significant, probably due to bioavailability limitations. With Soil B, the combined effect of toluene as cosubstrate and a surfactant pretreatment was studied and the hydrocarbons degradation was 29% higher in the toluene-amended columns than in the controls. Toluene removal was higher than 99% in all cases. Surfactant addition increased hydrocarbon degradation when toluene was also added suggesting that the biological reaction was the limiting process. The study shows the possibilities of using gaseous substrates, such as toluene, for the in situ or ex situ treatment of petroleum hydrocarbon-polluted soil in processes limited by the biological reaction. The main advantage of the treatment is that the compound can be easily and directly delivered to the polluted soil through the venting system.

  14. Polyphosphoester-based cationic nanoparticles serendipitously release integral biologically-active components to serve as novel degradable inducible nitric oxide synthase inhibitors.

    PubMed

    Shen, Yuefei; Zhang, Shiyi; Zhang, Fuwu; Loftis, Alexander; Pavía-Sanders, Adriana; Zou, Jiong; Fan, Jingwei; Taylor, John-Stephen A; Wooley, Karen L

    2013-10-18

    A degradable polyphosphoester (PPE)-based cationic nanoparticle (cSCK), which is integrated constructed as a novel degradable drug device, demonstrates surprisingly efficient inhibition of inducible nitric oxide synthase (iNOS) transcription, and eventually inhibits nitric oxide (NO) over-production, without loading of any specific therapeutic drugs. This system may serve as a promising anti-inflammatory agent toward the treatment of acute lung injury.

  15. Environmental Pollution

    ERIC Educational Resources Information Center

    Breitbeil, Fred W., III

    1973-01-01

    Presents a thorough overview of the many factors contributing to air and water pollution, outlines the chemical reactions involved in producing toxic end-products, and describes some of the consequences of pollutants on human health and ecosystems. (JR)

  16. Water Pollution

    MedlinePlus

    ... adjust the font size, or print this page. Water Pollution Table of Contents Health Studies & Clinical Trials ... Trials GuLF Study What NIEHS is Doing on Water Pollution Survival of the resilient: rapid killifish evolution ...

  17. Air pollution injury to plants

    SciTech Connect

    Seibert, R.J.

    1986-01-01

    The injuries to plants by oxidant air pollution can be used as biological indicators of pollution episodes. Bel W3 tobacco is often used as an indicator organism. Dogwood is another potential indicator organism. Specific growing procedures used for indicator organisms are described, as are diagnostic criteria for the type and extent of injuries.

  18. Pollution effects on fisheries — potential management activities

    NASA Astrophysics Data System (ADS)

    Sindermann, C. J.

    1980-03-01

    Management of ocean pollution must be based on the best available scientific information, with adequate consideration of economic, social, and political realities. Unfortunately, the best available scientific information about pollution effects on fisheries is often fragmentary, and often conjectural; therefore a primary concern of management should be a critical review and assessment of available factual information about effects of pollutants on fish and shellfish stocks. A major problem in any such review and assessment is the separation of pollutant effects from the effects of all the other environmental factors that influence survival and well-being of marine animals. Data from long-term monitoring of resource abundance, and from monitoring of all determinant environmental variables, will be required for analyses that lead to resolution of the problem. Information must also be acquired about fluxes of contaminants through resource-related ecosystems, and about contaminant effects on resource species as demonstrated in field and laboratory experiments. Other possible management activities include: (1) encouragement of continued efforts to document clearly the localized and general effects of pollution on living resources; (2) continued pressure to identify and use reliable biological indicators of environmental degradation (indicators of choice at present are: unusually high levels of genetic and other anomalies in the earliest life history stages; presence of pollution-associated disease signs, particularly fin erosion and ulcers, in fish; and biochemical/physiological changes); and (3) major efforts to reduce inputs of pollutants clearly demonstrated to be harmful to living resources, from point sources as well as ocean dumping. Such pollution management activities, based on continuous efforts in stock assessment, environmental assessment, and experimental studies, can help to insure that rational decisions will be made about uses and abuses of coastal

  19. Air Pollution.

    ERIC Educational Resources Information Center

    Gilpin, Alan

    A summary of one of our most pressing environmental problems, air pollution, is offered in this book by the Director of Air Pollution Control for the Queensland (Australia) State Government. Discussion of the subject is not restricted to Queensland or Australian problems and policies, however, but includes analysis of air pollution the world over.…

  20. Air Pollution.

    ERIC Educational Resources Information Center

    Barker, K.; And Others

    Pollution of the general environment, which exposes an entire population group for an indeterminate period of time, certainly constitutes a problem in public health. Serious aid pollution episodes have resulted in increased mortality and a possible relationship between chronic exposure to a polluted atmosphere and certain diseases has been…

  1. Air Pollution.

    ERIC Educational Resources Information Center

    Fox, Donald L.

    1989-01-01

    Materials related to air pollution are reviewed for the period January 1987, to October 1988. The topics are pollution monitoring, air pollution, and environmental chemistry. The organization consists of two major analytical divisions: (1) gaseous methods; and (2) aerosol and particulate methods. (MVL)

  2. Bioremediation of groundwater pollution.

    PubMed

    Crawford, R L

    1991-06-01

    Significant progress has been made in the past year towards an understanding of the microbial processes in subsurface environments that may allow natural microbial populations to be employed for bioremediation of groundwater pollution. Among the highlights were: the discovery of several previously unknown xenobiotic-degrading abilities in groundwater microorganisms; progress in using the unique abilities of methanotrophs to oxidize halogenated solvents; and characterizations of microbial populations from subsurface soils.

  3. Structural Analysis and Biological Toxicity of Aflatoxins B1 and B2 Degradation Products Following Detoxification by Ocimum basilicum and Cassia fistula Aqueous Extracts.

    PubMed

    Iram, Wajiha; Anjum, Tehmina; Iqbal, Mazhar; Ghaffar, Abdul; Abbas, Mateen; Khan, Abdul Muqeet

    2016-01-01

    This study showed the comparison between Ocimum basilicum and Cassia fistula (leaves and branch) aqueous extracts for their ability to detoxify of aflatoxins B1 and B2 (AFB1; 100 μg L(-1) and AFB2; 50 μg L(-1)) by In Vitro assays and decontamination studies. Results indicated that O. basilicum leaves extract was found to be highly significant (P < 0.05) in degrading AFB1 and AFB2, i.e., 90.4 and 88.6%, respectively. However, O. basilicum branch, C. fistula leaves and branch extracts proved to be less efficient in degrading these aflatoxins, under optimized conditions, i.e., pH 8, temperature 30°C and incubation period of 72 h. Moreover the antifungal activity of these plants extracts were also tested. The findings depicted that O. basilicum leaves extract showed maximum growth inhibition of aflatoxigenic isolates, i.e., 82-87% as compared to other tested plants extracts. The structural elucidation of degraded toxin products by LCMS/MS analysis showed that nine degraded products of AFB1 and AFB2 were formed. MS/MS spectra showed that most of the products were formed by the removal of double bond in the terminal furan ring and modification of lactone group indicating less toxicity as compared to parent compounds. Brine shrimps bioassay further confirmed the low toxicity of degraded products, showing that O. basilicum leaves extract can be used as an effective tool for the detoxification of aflatoxins.

  4. Soil Degradation: A North American perspective

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil can be degraded through erosion and formation of undesirable physical, chemical, or biological properties due to industrialization or use of inappropriate farming practices that supersede natural regeneration. Soil degradation reflects unsustainable resource management that is global in scope a...

  5. Screening of PAH-degrading bacteria in a mangrove swamp using PCR-RFLP.

    PubMed

    Liu, HuiJie; Yang, CaiYun; Tian, Yun; Lin, GuangHui; Zheng, TianLing

    2010-11-01

    There are abundant PAH-degrading bacteria in mangrove sediments, and it is very important to screen the high efficiency degraders in order to perform bioremediation of PAH polluted environments. In order to obtain the more highly efficient PAH-degrading bacteria from a mangrove swamp, we first obtained 62 strains of PAH-degrading bacteria using traditional culture methods and based on their morphological characteristics. We then used the modern molecular biological technology of PCR-RFLP, in which the 16S rDNA of these strains were digested by different enzymes. Based on differences in the PCR-RFLP profiles, we obtained five strains of phenanthrene-degrading bacteria, five strains of pyrene-degrading bacteria, four strains of fluoranthene-degrading bacteria, five strains of benzo[a]pyrene-degrading bacteria and two strains of mixed PAH-degrading bacteria (including phenanthrene, pyrene, fluoranthene and benzo[a]pyrene). Finally, a total of 14 different PAH-degrading bacteria were obtained. The 16S rDNA sequences of these strains were aligned with the BLAST program on the NCBI website and it was found that they belonged to the α-proteobacteria and γ-proteobacteria, including four strains, where the similarities were no more than 97% and which were suspected therefore to be new species. This study indicated that PCR-RFLP was a very important method to screen degrading-bacteria, and also a significant molecular biological tool for the rapid classification and accurate identification of many different strains. On the other hand, it also showed that rich bacterial resources existed in mangrove areas, and that exploring and developing the functional microorganism from these mangrove areas would have wide use in the study of bioremediation of contaminated environments in the future.

  6. PRESENTED AT TRIANGLE CONSORTIUM OF REPRODUCTIVE BIOLOGY, CHAPEL HILL, NC: GST M1 GENOTYPE INFLUENCES SPERM DNA DAMAGE ASSOCIATED WITH EXPOSURE TO AIR POLLUTION

    EPA Science Inventory

    Exposure to episodic air pollution in the Czech Republic has been associated with abnormal semen quality and sperm DNA damage (EHP 108:887;2000). A subsequentlongitudinal study evaluated semenfrom 36 men sampled up to 7 times over a period of two years to capture exposures durin...

  7. Degradation of degradable starch-polyethylene plastics in a compost environment

    SciTech Connect

    Johnson, K.E.; Pometto, A.L. III; Nikolov, Z.L. )

    1993-04-01

    Degradable plastics have differing degradation rates. Three types of degradation of polyethylene in the starch-polyethylene polymers can occur: chemical degradation, photodegradation, and biological degradation. This study examines all three types of degradation in 11 commercially produced degradable starch-polyethylene bags. Different rates for chemical and photo-degradation were found within a 20 day or an 8-week period. Results indicated that both the 70[degree]C oven and HT-HH film treatments were appropriate methods to evaluate oxidative degradation. In a compost environment, oxygen tension on the surface of the film appears to be the rate-limiting component for both chemical and biological degradation. Levels of starch in all bags was similar, so the prooxidant additive was critical in promoting the oxidative degradation of polyethylene. The Fe-Mn additive displayed the best catalytic activity. This study overall confirms degradation of starch-polyethylene plastics in a natural environment. 17 refs., 6 figs., 2 tabs.

  8. Structural Analysis and Biological Toxicity of Aflatoxins B1 and B2 Degradation Products Following Detoxification by Ocimum basilicum and Cassia fistula Aqueous Extracts

    PubMed Central

    Iram, Wajiha; Anjum, Tehmina; Iqbal, Mazhar; Ghaffar, Abdul; Abbas, Mateen; Khan, Abdul Muqeet

    2016-01-01

    This study showed the comparison between Ocimum basilicum and Cassia fistula (leaves and branch) aqueous extracts for their ability to detoxify of aflatoxins B1 and B2 (AFB1; 100 μg L-1 and AFB2; 50 μg L-1) by In Vitro assays and decontamination studies. Results indicated that O. basilicum leaves extract was found to be highly significant (P < 0.05) in degrading AFB1 and AFB2, i.e., 90.4 and 88.6%, respectively. However, O. basilicum branch, C. fistula leaves and branch extracts proved to be less efficient in degrading these aflatoxins, under optimized conditions, i.e., pH 8, temperature 30°C and incubation period of 72 h. Moreover the antifungal activity of these plants extracts were also tested. The findings depicted that O. basilicum leaves extract showed maximum growth inhibition of aflatoxigenic isolates, i.e., 82–87% as compared to other tested plants extracts. The structural elucidation of degraded toxin products by LCMS/MS analysis showed that nine degraded products of AFB1 and AFB2 were formed. MS/MS spectra showed that most of the products were formed by the removal of double bond in the terminal furan ring and modification of lactone group indicating less toxicity as compared to parent compounds. Brine shrimps bioassay further confirmed the low toxicity of degraded products, showing that O. basilicum leaves extract can be used as an effective tool for the detoxification of aflatoxins. PMID:27471501

  9. Metal pollution of river Msimbazi, Tanzania

    SciTech Connect

    Ak'habuhaya, J.; Lodenius, M. )

    1988-01-01

    The Misimbazi River in Dar es Salaam is polluted with industrial, urban and agricultural waste waters. A preliminary investigation on the extent of metal pollution (Hg, Cr, Cu, Zn, Fe, Ni, Cd, Mn, Al) was made from samples of sediments and biological indicators. The metal concentrations were in general low, but some of our results indicated industrial pollution.

  10. Autopsy tissues as biological monitors of human exposure to environmental pollutants. A case study: Concentrations of metals and PCDD/Fs in subjects living near a hazardous waste incinerator.

    PubMed

    Domingo, José L; García, Francisco; Nadal, Martí; Schuhmacher, Marta

    2017-04-01

    Human biomonitoring is of tremendous importance to prevent potential adverse effects derived from human exposure to chemicals. Blood and urine are among the biological monitors more frequently used. However, biological matrices such as breast milk, hair, nails, saliva, feces, teeth, and expired air are also often used. In addition, and focused mainly on long-term exposure, adipose tissue and other human tissues like bone, liver, brain or kidney, are also used as biological monitors of certain substances, especially for long-term biomonitoring. However, for this kind of tissues sampling is always a limiting factor. In this paper, we have examined the role of autopsy tissues as biological monitors of human exposure to environmental pollutants. For it, we have used a case study conducted near a hazardous waste incinerator (HWI) in Catalonia (Spain), in which the concentrations of metals and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), have been periodically determined in autopsy tissues of subjects living in the area under potential influence of the facility. This case study does not show advantages -in comparison to other appropriate biomonitors such as blood- in using autopsy tissues in the monitoring of long-term exposure to metals and PCDD/Fs.

  11. Oxidative degradation of alternative gasoline oxygenates in aqueous solution by ultrasonic irradiation: mechanistic study.

    PubMed

    Kim, Duk Kyung; O'Shea, Kevin E; Cooper, William J

    2012-07-15

    Widespread pollution has been associated with gasoline oxygenates of branched ethers methyl tert-butyl ether (MTBE), di-isopropyl ether (DIPE), ethyl tert-butyl ether (ETBE), and tert-amyl ether (TAME) which enter groundwater. The contaminated plume develops rapidly and treatment for the removal/destruction of these ethers is difficult when using conventional methods. Degradation of MTBE, with biological methods and advanced oxidation processes, are rather well known; however, fewer studies have been reported for degradation of alternative oxygenates. Degradation of alternative gasoline oxygenates (DIPE, ETBE, and TAME) by ultrasonic irradiation in aqueous oxygen saturation was investigated to elucidate degradation pathways. Detailed degradation mechanisms are proposed for each gasoline oxygenate. The common major degradation pathways are proposed to involve abstraction of α-hydrogen atoms by hydroxyl radicals generated during ultrasound cavitation and low temperature pyrolytic degradation of ETBE and TAME. Even some of the products from β-H abstraction overlap with those from high temperature pyrolysis, the effect of β-H abstraction was not shown clearly from product study because of possible 1,5 H-transfer inside cavitating bubbles. Formation of hydrogen peroxide and organic peroxides was also determined during sonolysis. These data provide a better understanding of the degradation pathways of gasoline oxygenates by sonolysis in aqueous solutions. The approach may also serve as a model for others interested in the details of sonolysis.

  12. Changes in the ecological and biological properties of ordinary chernozems polluted by heavy metals of the second hazard class (Mo, Co, Cr, and Ni)

    NASA Astrophysics Data System (ADS)

    Kolesnikov, S. I.; Evreinova, A. V.; Kazeev, K. Sh.; Val'Kov, V. F.

    2009-08-01

    The pollution of ordinary chernozems by heavy metals of the second hazard class (Mo, Co, Cr, and Ni) results in a decrease in the numbers of saprotrophic bacteria and fungi and bacteria of the Azotobacter genus; the catalase and invertase activities and the rates of the cellulose and urea decomposition also decrease. The soil phytotoxicity becomes higher. With respect to their ecological hazard, the studied heavy metals may be arranged into the following sequence: Cr > Co ≥ Ni > Mo.

  13. ENANTIOMER-SPECIFIC EFFECTS OF CHIRAL POLLUTANTS

    EPA Science Inventory

    Enantiomers, the mirror image isomers of chiral pollutants, are known to be selective in their interaction with other chiral molecules, including enzymes and other biochemicals. Considerable research has shown, for example, that chiral pesticides are degraded selectively by micr...

  14. Effects of mass transfer and light intensity on substrate biological degradation by immobilized photosynthetic bacteria within an annular fiber-illuminating biofilm reactor.

    PubMed

    Zhang, Chuan; Zhang, Huan; Zhang, Zhiping; Jiao, Youzhou; Zhang, Quanguo

    2014-02-05

    In this work, effects of mass transfer and light intensity on performance of substrate biodegradation by cell-immobilized photosynthetic bacteria were investigated within an annular fiber-illuminating bioreactor (AFIBR). In AFIBR, stable biofilm of photosynthetic bacteria was generated on the surface of side-glowing optical fiber to provide sufficient light supply and uniform light distribution in cell-immobilized zone for continuous substrate biodegradation during hydrogen production process. To optimize operation parameters for substrate degradation, a two-dimensional mass transfer model based on experimental data to describe coupled processes of substrate transfer and biodegradation in biofilm with substrate diffusion and convection in bulk flow region was proposed. Investigations on influences of substrate concentration, flow rate and light intensity were carried out. It was showed that the optimum operational parameters for the substrate degradation in the AFIBR are: 10g/l substrate concentration, 100ml/h flow rate and 3.1W/m(2) light intensity.

  15. Evaluation of HDPE and LDPE degradation by fungus, implemented by statistical optimization

    PubMed Central

    Ojha, Nupur; Pradhan, Neha; Singh, Surjit; Barla, Anil; Shrivastava, Anamika; Khatua, Pradip; Rai, Vivek; Bose, Sutapa

    2017-01-01

    Plastic in any form is a nuisance to the well-being of the environment. The ‘pestilence’ caused by it is mainly due to its non-degradable nature. With the industrial boom and the population explosion, the usage of plastic products has increased. A steady increase has been observed in the use of plastic products, and this has accelerated the pollution. Several attempts have been made to curb the problem at large by resorting to both chemical and biological methods. Chemical methods have only resulted in furthering the pollution by releasing toxic gases into the atmosphere; whereas; biological methods have been found to be eco-friendly however they are not cost effective. This paves the way for the current study where fungal isolates have been used to degrade polyethylene sheets (HDPE, LDPE). Two potential fungal strains, namely, Penicillium oxalicum NS4 (KU559906) and Penicillium chrysogenum NS10 (KU559907) had been isolated and identified to have plastic degrading abilities. Further, the growth medium for the strains was optimized with the help of RSM. The plastic sheets were subjected to treatment with microbial culture for 90 days. The extent of degradation was analyzed by, FE-SEM, AFM and FTIR. Morphological changes in the plastic sheet were determined. PMID:28051105

  16. Evaluation of HDPE and LDPE degradation by fungus, implemented by statistical optimization

    NASA Astrophysics Data System (ADS)

    Ojha, Nupur; Pradhan, Neha; Singh, Surjit; Barla, Anil; Shrivastava, Anamika; Khatua, Pradip; Rai, Vivek; Bose, Sutapa

    2017-01-01

    Plastic in any form is a nuisance to the well-being of the environment. The ‘pestilence’ caused by it is mainly due to its non-degradable nature. With the industrial boom and the population explosion, the usage of plastic products has increased. A steady increase has been observed in the use of plastic products, and this has accelerated the pollution. Several attempts have been made to curb the problem at large by resorting to both chemical and biological methods. Chemical methods have only resulted in furthering the pollution by releasing toxic gases into the atmosphere; whereas; biological methods have been found to be eco-friendly however they are not cost effective. This paves the way for the current study where fungal isolates have been used to degrade polyethylene sheets (HDPE, LDPE). Two potential fungal strains, namely, Penicillium oxalicum NS4 (KU559906) and Penicillium chrysogenum NS10 (KU559907) had been isolated and identified to have plastic degrading abilities. Further, the growth medium for the strains was optimized with the help of RSM. The plastic sheets were subjected to treatment with microbial culture for 90 days. The extent of degradation was analyzed by, FE-SEM, AFM and FTIR. Morphological changes in the plastic sheet were determined.

  17. The Degradation of a Nation.

    ERIC Educational Resources Information Center

    Morozova, Galina Fedorouna

    1995-01-01

    Maintains that the process of national degradation is a real danger and concern of all Russian society. Discusses environmental concerns, such as water, soil, and air pollution; falling birth rates; aging of the population; crime; and decline in moral values. Concludes that it is imperative for all citizens to stop and reverse these trends. (CFR)

  18. Air Pollution.

    EPA Science Inventory

    Air quality is affected by many types of pollutants that are emitted from various sources, including stationary and mobile. These sources release both criteria and hazardous air pollutants, which cause health effects, ecological harm, and material damage. They are generally categ...

  19. Air Pollution.

    ERIC Educational Resources Information Center

    Scorer, Richard S.

    The purpose of this book is to describe the basic mechanisms whereby pollution is transported and diffused in the atmosphere. It is designed to give practitioners an understanding of basic mechanics and physics so they may have a correct basis on which to formulate their decisions related to practical air pollution control problems. Since many…

  20. Silicate, borosilicate, and borate bioactive glass scaffolds with controllable degradation rate for bone tissue engineering applications. II. In vitro and in vivo biological evaluation.

    PubMed

    Fu, Qiang; Rahaman, Mohamed N; Bal, B Sonny; Bonewald, Lynda F; Kuroki, Keiichi; Brown, Roger F

    2010-10-01

    In Part I, the in vitro degradation of bioactivAR52115e glass scaffolds with a microstructure similar to that of human trabecular bone, but with three different compositions, was investigated as a function of immersion time in a simulated body fluid. The glasses consisted of a silicate (13-93) composition, a borosilicate composition (designated 13-93B1), and a borate composition (13-93B3), in which one-third or all of the SiO2 content of 13-93 was replaced by B2O3, respectively. This work is an extension of Part I, to investigate the effect of the glass composition on the in vitro response of osteogenic MLO-A5 cells to these scaffolds, and on the ability of the scaffolds to support tissue infiltration in a rat subcutaneous implantation model. The results of assays for cell viability and alkaline phosphatase activity showed that the slower degrading silicate 13-93 and borosilicate 13-93B1 scaffolds were far better than the borate 13-93B3 scaffolds in supporting cell proliferation and function. However, all three groups of scaffolds showed the ability to support tissue infiltration in vivo after implantation for 6 weeks. The results indicate that the required bioactivity and degradation rate may be achieved by substituting an appropriate amount of SiO2 in 13-93 glass with B2O3, and that these trabecular glass scaffolds could serve as substrates for the repair and regeneration of contained bone defects.

  1. Improving the degradation behavior and in vitro biological property of nano-hydroxyapatite surface- grafted with the assist of citric acid.

    PubMed

    Jiang, Liuyun; Jiang, Lixin; Xiong, Chengdong; Su, Shengpei

    2016-10-01

    To obtain ideal nano-hydroxyapatite(n-HA) filler for poly(lactide-co-glycolide) (PLGA), a new surface-grafting with the assist of citric acid for nano-hydroxyapatite (n-HA) was designed, and the effect of n-HA surface-grafted with or without citric acid on in vitro degradation behavior and cells viability was studied by the experiments of soaking in simulated body fluid (SBF) and incubating with human osteoblast-like cells (MG-63). The change of pH value, tensile strength reduction, the surface deposits, cells attachment and proliferation of samples during the soaking and incubation were investigated by means of pH meter, electromechanical universal tester, scanning electron microscope (SEM) coupled with energy-dispersive spectro-scopy (EDS), fluorescence microscope and MTT method. The results showed that the introduction of citric acid not only delayed the strength reduction during the degradation by inhibiting the detachment of n-HA from PLGA, but also endowed it better cell attachment and proliferation, suggesting that the n-HA surface-grafted with the assist of citric acid was an important bioactive ceramic fillers for PLGA used as bone materials.

  2. Biological monitoring

    SciTech Connect

    Ho, M.H.; Dillon, H.K.

    1986-02-01

    Biological monitoring is defined as the measurement and assessment of workplace agents or their metabolites in tissues, secreta, excreta, expired air, or any combination of these to evaluate exposure and health risk compared to an appropriate reference. Biological monitoring offers several advantages: it takes into account individual variability in biological activity resulting from a chemical insult. It takes into account the effects of personal physical activity and individual life styles. It is a valuable adjunct to ambient monitoring and health surveillance. The importance of chemical speciation in the toxicity of pollutants is discussed. Basic protocols for lead, aluminum, cadmium, mercury, selenium, and nickel are presented. Basic criteria for biological monitoring methods are presented. 11 references, 1 table.

  3. Indoor air pollution.

    PubMed

    Gold, D R

    1992-06-01

    This article summarizes the health effects of indoor air pollutants and the modalities available to control them. The pollutants discussed include active and passive exposure to tobacco smoke; combustion products of carbon monoxide; nitrogen dioxide; products of biofuels, including wood and coal; biologic agents leading to immune responses, such as house dust mites, cockroaches, fungi, animal dander, and urine; biologic agents associated with infection such as Legionella and tuberculosis; formaldehyde; and volatile organic compounds. An approach to assessing building-related illness and "tight building" syndrome is presented. Finally, the article reviews recent data on hospital-related asthma and exposures to potential respiratory hazards such as antineoplastic agents, anesthetic gases, and ethylene oxide.

  4. Indoor air pollution

    SciTech Connect

    Gold, D.R. )

    1992-06-01

    This article summarizes the health effects of indoor air pollutants and the modalities available to control them. The pollutants discussed include active and passive exposure to tobacco smoke; combustion products of carbon monoxide; nitrogen dioxide; products of biofuels, including wood and coal; biologic agents leading to immune responses, such as house dust mites, cockroaches, fungi, animal dander, and urine; biologic agents associated with infection such as Legionella and tuberculosis; formaldehyde; and volatile organic compounds. An approach to assessing building-related illness and tight building' syndrome is presented. Finally, the article reviews recent data on hospital-related asthma and exposures to potential respiratory hazards such as antineoplastic agents, anesthetic gases, and ethylene oxide.88 references.

  5. Refractory organic pollutants and toxicity in pulp and paper mill wastewaters.

    PubMed

    Lindholm-Lehto, Petra C; Knuutinen, Juha S; Ahkola, Heidi S J; Herve, Sirpa H

    2015-05-01

    This review describes medium and high molecular weight organic material found in wastewaters from pulp and paper industry. The aim is to review the versatile pollutants and the analysis methods for their determination. Among other pollutants, biocides, extractives, and lignin-derived compounds are major contributors to harmful effects, such as toxicity, of industrial wastewaters. Toxicity of wastewaters from pulp and paper mills is briefly evaluated including the methods for toxicity analyses. Traditionally, wastewater purification includes mechanical treatment followed by chemical and/or biological treatment processes. A variety of methods are available for the purification of industrial wastewaters, including aerobic and anaerobic processes. However, some fractions of organic material, such as lignin and its derivatives, are difficult to degrade. Therefore, novel chemical methods, including electrochemical and oxidation processes, have been developed for separate use or in combination with biological treatment processes.

  6. Ozone Pollution

    EPA Pesticide Factsheets

    Known as tropospheric or ground-level ozone, this gas is harmful to human heath and the environment. Since it forms from emissions of volatile organic compounds (VOCs) and nitrogen oxides (NOx), these pollutants are regulated under air quality standards.

  7. Light Pollution

    ERIC Educational Resources Information Center

    Riegel, Kurt W.

    1973-01-01

    Outdoor lighting is light pollution which handicaps certain astronomical programs. Protective measures must be adopted by the government to aid observational astronomy without sacrificing legitimate outdoor lighting needs. (PS)

  8. Total petroleum hydrocarbons and heavy metals in the surface sediments of Bohai Bay, China: long-term variations in pollution status and adverse biological risk.

    PubMed

    Zhou, Ran; Qin, Xuebo; Peng, Shitao; Deng, Shihuai

    2014-06-15

    Surface sediments collected from 2001 to 2011 were analyzed for total petroleum hydrocarbons (TPH) and five heavy metals. The sediment concentration ranges of TPH, Zn, Cu, Pb, Cd and Hg were 6.3-535 μg/g, 58-332 μg/g, 7.2-63 μg/g, 4.3-138 μg/g, 0-0.98μg/g, and 0.10-0.68 μg/g, respectively. These results met the highest marine sediment quality standards in China, indicating that the sediment was fairly clean. However, based on the effects range-median (ERM) quotient method, the calculated values for all of the sampling sites were higher than 0.10, suggesting that there was a potential adverse biological risk in Bohai Bay. According to the calculated results, the biological risk decreased from 2001 to 2007 and increased afterwards. High-risk sites were mainly distributed along the coast. This study suggests that anthropogenic influences might be responsible for the potential risk of adverse biological effects from TPH and heavy metals in Bohai Bay.

  9. Response of autochthonous microbiota of diesel polluted soils to land-farming treatments.

    PubMed

    Silva-Castro, Gloria Andrea; Uad, Imane; Rodríguez-Calvo, Alfonso; González-López, Jesús; Calvo, Concepción

    2015-02-01

    This study investigated the response of autochthonous microorganisms of diesel polluted soils to land-farming treatments. Inorganic NPK (nitrogen, phosphorous, and potassium) fertilizer and Ivey surfactant were applied alone or in combination as biostimulating agents. The study was carried out in experimental separated land-farming plots performed with two soils: a sandy clay soil with low biological activity and a sandy clay soil with higher biological activity, contaminated with two concentrations of diesel: 10,000 and 20,000mgkg(-1). Bacterial growth, dehydrogenase activity and CO2 production were the biological parameters evaluated. Non-metric multidimensional scaling analysis proved that moisture content showed a tendency related to microbial growth and that heterotrophic and degrading microorganisms had the best relationship. Initial biological activity of soil influenced the response with 11.1% of variability attributed to this parameter. Soils with low activity had higher degree of response to nutrient addition.

  10. Atmospheric pollution

    SciTech Connect

    Pickett, E.E.

    1987-01-01

    Atmospheric pollution (AP), its causes, and measures to prevent or reduce it are examined in reviews and reports presented at a workshop held in Damascus, Syria in August 1985. Topics discussed include AP and planning studies, emission sources, pollutant formation and transformation, AP effects on man and vegetation, AP control, atmospheric dispersion mechanisms and modeling, sampling and analysis techniques, air-quality monitoring, and applications. Diagrams, graphs, and tables of numerical data are provided.

  11. Parasites of flounder (Platichthys flesus L.) from the German Bight, North Sea, and their potential use in biological effects monitoring. C. Pollution effects on the parasite community and a comparison to biomarker responses

    NASA Astrophysics Data System (ADS)

    Schmidt, V.; Zander, S.; Körting, W.; Broeg, K.; von Westernhagen, H.; Dizer, H.; Hansen, P. D.; Skouras, A.; Steinhagen, D.

    2003-10-01

    In the frame of an integrated biological effect monitoring programme, the parasite community of flounder (Platichthys flesus) was investigated at different locations in the German Bight from 1995 to 2000. In order to assess the impact of environmental contamination caused by anthropogenic activities on the parasite community, selected parasitological parameters that displayed significant differences between the sampling sites were subjected to correlation analyses with site-specific contamination and individual pollution loads of their fish hosts. In addition, correlation analyses were conducted with the responses of selected genetic, biochemical, histopathological, physiological and immunological parameters of fish, used as potential biomarkers. In total, 802 flounder were analysed for these parameters. Information on the chemical background at the sampling sites was derived from sediment samples and from 120 samples of blue mussel (Mytilus edulis) tissue, collected at each of the sampling sites. Based on chemical data available from the sediment and blue mussel samples, a pollution gradient could be established between the sampling sites for individual contaminants. The relative abundance of Acanthochondria cornuta, Cucullanus heterochrous and Zoogonoides viviparus, and the community measures species richness and number of heteroxenous species decreased with increasing concentrations of individual heavy metals or hydrocarbons in sediment and blue mussel samples. Most of the parasitological parameters significantly reflected the established site-specific contamination gradient, when data were pooled over all sampling campaigns. Significant correlations were also found with the contamination level of individual flounder. The parasitological parameters included the parasite species Lepeophtheirus pectoralis and Lernaeocera branchialis, which were not correlated to site-specific contamination. Several biomarkers were significantly correlated to the abundance of

  12. Construction and economics of a pilot/full-scale biological trickling filter reactor for the removal of volatile organic compounds from polluted air.

    PubMed

    Deshusses, M A; Webster, T S

    2000-11-01

    The design and the construction of an actual 8.7-m3 pilot/full-scale biotrickling filter for waste air treatment is described and compared with a previous conceptual scale-up of a laboratory reactor. The reactor construction costs are detailed and show that about one-half of the total reactor costs ($97,000 out of $178,000) was for personnel and engineering time, whereas approximately 20% was for monitoring and control equipment. A detailed treatment cost analysis demonstrated that, for an empty bed contact time of 90 sec, the overall treatment costs (including capital charges) were as low as $8.7/1000 m3air in the case where a nonchlorinated volatile organic compound (VOC) was treated, and $14/1000 m3air for chlorinated compounds such as CH2Cl2. Comparison of these costs with conventional air pollution control techniques demonstrates excellent perspectives for more field applications of biotrickling filters. As the specific costs of building and operating biotrickling filter reactors decrease with increasing size of the reactor, the cost benefit of biotrickling filtration is expected to increase for full technical-scale bioreactors.

  13. Agricultural and urban pollution

    NASA Technical Reports Server (NTRS)

    Brehmer, M. L.

    1972-01-01

    The degradation produced by the introduction of agricultural and urban wastes into estuarine systems, with emphasis on the Chesapeake Bay area, is discussed. The subjects presented are: (1) effects of sediment loading and (2) organic and nutrient loading problems. The impact of high turbidity on the biological life of the bay is analyzed. The sources of nutrients which produce over-enrichment of the waters and the subsequent production of phytoplankton are examined.

  14. Urban pollution.

    PubMed

    Sancini, Angela; Tomei, Francesco; Tomei, Gianfranco; Caciari, Tiziana; Di Giorgio, Valeria; André, Jean-Claude; Palermo, Paola; Andreozzi, Giorgia; Nardone, Nadia; Schifano, Maria Pia; Fiaschetti, Maria; Cetica, Carlotta; Ciarrocca, Manuela

    2012-01-01

    Air pollution represents a health risk for people living in urban environment. Urban air consists in a complex mixture of chemicals and carcinogens and its effects on health can be summarized in acute respiratory effects, neoplastic nonneoplastic (e.g. chronic bronchitis) chronic respiratory effects, and effects on other organs and systems. Air pollution may be defined according to origin of the phenomena that determine it: natural causes (natural fumes, decomposition, volcanic ash) or anthropogenic causes which are the result of human activities (industrial and civil emissions). Transport is the sector that more than others contributes to the deterioration of air quality in cities. In this context, in recent years, governments of the territory were asked to advance policies aimed at solving problems related to pollution. In consideration of the many effects on health caused by pollution it becomes necessary to know the risks from exposure to various environmental pollutants and to limit and control their effects. Many are the categories of "outdoor" workers, who daily serve the in urban environment: police, drivers, newsagents, etc.

  15. Application of System Dynamics technique to simulate the fate of persistent organic pollutants in soils.

    PubMed

    Chaves, R; López, D; Macías, F; Casares, J; Monterroso, C

    2013-03-01

    Persistent organic pollutants (POPs) are within the most dangerous pollutants released into the environment by human activities. Due to their resistance to degradation (chemical, biological or photolytic), it is critical to assess the fate and environmental hazards of the exchange of POPs between different environmental media. System Dynamics enables to represent complex systems and analyze their dynamic behavior. It provides a highly visual representation of the structure of the system and the existing relationships between the several parameters and variables, facilitating the understanding of the behavior of the system. In the present study the fate of γ-hexachlorocyclohexane (lindane) in a contaminated soil was modeled using the Vensim® simulation software. Results show a gradual decrease in the lindane content in the soil during a simulation period of 10 years. The most important route affecting the concentrations of the contaminant was the biochemical degradation, followed by infiltration and hydrodynamic dispersion. The model appeared to be highly sensitive to the half-life of the pollutant, which value depends on environmental conditions and directly affects the biochemical degradation.

  16. Efficacy of SnO2 nanoparticles toward photocatalytic degradation of methylene blue dye.

    PubMed

    Elango, Ganesh; Roopan, Selvaraj Mohana

    2016-02-01

    Maximum pollutants in the industrial and domestic waste water effluents from any sources include pathogens and organic chemicals, which can be removed before discharging into the water bodies. Methylene blue has been considered as one of the major water contaminated pollutants. Such pollutant is dominant in surface water and groundwater. It will cause irreversible hazards to human and aquatic life. Nanotechnology plays a major role in degrading such type of pollutant. In order to fulfill today's requirement, we have decided to handle the green synthesis of nanoparticles and its application by merging important fields like chemistry, environmental science, and biotechnology. Here our work emphasizes on the biological synthesis of SnO2 nanoparticles (SnO2 NPs) using the methanolic extract of Cyphomandra betacea (C.betacea), and it was confirmed by various characterization techniques such as UV-visible spectroscopy, FT-IR, XRD, SEM, particle size analyzer, zeta potential, and TEM. The obtained results stated that the synthesized SnO2 NPs were in rod shape with an average size of 21nm, which resulted in a product of nanobiotechnology. Further, we have utilized the environmental-friendly synthesized SnO2 NPs photocatalytic degradation of environmental concern methylene blue with first-order kinetics. In this paper, we have attempted to prove that secondary metabolite-entrapped SnO2 NPs are non-toxic to the environment.

  17. Hysterothylacium aduncum (Nematoda, Anisakidae) with a new host record from the common sole Solea solea (Soleidae) and its role as a biological indicator of pollution.

    PubMed

    Abdel-Ghaffar, Fathy; Abdel-Gaber, Rewaida; Bashtar, Abdel-Rahman; Morsy, Kareem; Mehlhorn, Heinz; Al Quraishy, Saleh; Saleh, Rehab

    2015-02-01

    Hysterothylacium aduncum (Nematoda, Anisakidae) was isolated from the intestine of the common sole Solea solea (Family, Soleidae) collected from coasts along Alexandria City at the Mediterranean Sea in Egypt, during the period from May to September 2013. Light and scanning electron microscopy revealed that this nematode parasite belongs to the family Anisakidae in the genus Hysterothylacium. The type species is named H. aduncum, based on the presence of three interlocked lips with the interlabium in between, the presence of cephalic papillae, and large numbers of caudal papillae in males. Body measurements showed that the male worms were smaller than females measuring 13.9-18 mm (16.2 ± 0.2) in length and 0.26-0.34 mm (0.30 ± 0.01) in width. Females measured 20.5-24.5 mm (22.7 ± 0.2) in length and 0.41-0.52 mm (0.45 ± 0.01) in width. The morphological characteristics of this species was confirmed by molecular analysis of 18S rDNA for these parasites followed by comparison between sequence data for them with those obtained from the Genbank showing that H. aduncum is deeply embedded in the genus Hysterothylacium with a sequence similarity between 95.5-94.3 % with close relationships to other H. aduncum specimens and Hysterothylacium sp.. Furthermore, it was shown that this parasitic nematode is able to accumulate larger concentrations of heavy metals such as Fe, Cu, Cd, and Ni within its tissues than of its host fish and thus it can be used as a useful bio-indicator of water pollution.

  18. Community Analysis and Recovery of Phenol-degrading Bacteria from Drinking Water Biofilters.

    PubMed

    Gu, Qihui; Wu, Qingping; Zhang, Jumei; Guo, Weipeng; Wu, Huiqing; Sun, Ming

    2016-01-01

    Phenol is a ubiquitous organic contaminant in drinking water. Biodegradation plays an important role in the elimination of phenol pollution in the environment, but the information about phenol removal by drinking water biofilters is still lacking. Herein, we study an acclimated bacterial community that can degrade over 80% of 300 mg/L phenol within 3 days. PCR detection of genotypes involved in bacterial phenol degradation revealed that the degradation pathways contained the initial oxidative attack by phenol hydroxylase, and subsequent ring fission by catechol 1,2-dioxygenase. Based on the PCR denatured gradient gel electrophoresis (PCR-DGGE) profiles of bacteria from biological activated carbon (BAC), the predominant bacteria in drinking water biofilters including Delftia sp., Achromobacter sp., and Agrobacterium sp., which together comprised up to 50% of the total microorganisms. In addition, a shift in bacterial community structure was observed during phenol biodegradation. Furthermore, the most effective phenol-degrading strain DW-1 that correspond to the main band in denaturing gradient gel electrophoresis (DGGE) profile was isolated and identified as Acinetobacter sp., according to phylogenetic analyses of the 16S ribosomal ribonucleic acid (rRNA) gene sequences. The strain DW-1 also produced the most important enzyme, phenol hydroxylase, and it also exhibited a good ability to degrade phenol when immobilized on granular active carbon (GAC). This study indicates that the enrichment culture has great potential application for treatment of phenol-polluted drinking water sources, and the indigenous phenol-degrading microorganism could recover from drinking water biofilters as an efficient resource for phenol removal. Therefore, the aim of this study is to draw attention to recover native phenol-degrading bacteria from drinking water biofilters, and use these native microorganisms as phenolic water remediation in drinking water sources.

  19. Community Analysis and Recovery of Phenol-degrading Bacteria from Drinking Water Biofilters

    PubMed Central

    Gu, Qihui; Wu, Qingping; Zhang, Jumei; Guo, Weipeng; Wu, Huiqing; Sun, Ming

    2016-01-01

    Phenol is a ubiquitous organic contaminant in drinking water. Biodegradation plays an important role in the elimination of phenol pollution in the environment, but the information about phenol removal by drinking water biofilters is still lacking. Herein, we study an acclimated bacterial community that can degrade over 80% of 300 mg/L phenol within 3 days. PCR detection of genotypes involved in bacterial phenol degradation revealed that the degradation pathways contained the initial oxidative attack by phenol hydroxylase, and subsequent ring fission by catechol 1,2-dioxygenase. Based on the PCR denatured gradient gel electrophoresis (PCR-DGGE) profiles of bacteria from biological activated carbon (BAC), the predominant bacteria in drinking water biofilters including Delftia sp., Achromobacter sp., and Agrobacterium sp., which together comprised up to 50% of the total microorganisms. In addition, a shift in bacterial community structure was observed during phenol biodegradation. Furthermore, the most effective phenol-degrading strain DW-1 that correspond to the main band in denaturing gradient gel electrophoresis (DGGE) profile was isolated and identified as Acinetobacter sp., according to phylogenetic analyses of the 16S ribosomal ribonucleic acid (rRNA) gene sequences. The strain DW-1 also produced the most important enzyme, phenol hydroxylase, and it also exhibited a good ability to degrade phenol when immobilized on granular active carbon (GAC). This study indicates that the enrichment culture has great potential application for treatment of phenol-polluted drinking water sources, and the indigenous phenol-degrading microorganism could recover from drinking water biofilters as an efficient resource for phenol removal. Therefore, the aim of this study is to draw attention to recover native phenol-degrading bacteria from drinking water biofilters, and use these native microorganisms as phenolic water remediation in drinking water sources. PMID:27148185

  20. DDE remediation and degradation.

    PubMed

    Thomas, John E; Ou, Li-Tse; All-Agely, Abid

    2008-01-01

    DDT and its metabolites, DDD and DDE, have been shown to be recalcitrant to degradation. The parent compound, DDT, was used extensively worldwide starting in 1939 and was banned in the United States in 1973. The daughter compound, DDE, may result from aerobic degradation, abiotic dehydrochlorination, or photochemical decomposition. DDE has also occurred as a contaminant in commercial-grade DDT. The p,p'-DDE isomer is more biologically active than the o,p-DDE, with a reported half-life of -5.7 years. However, when DDT was repeatedly applied to the soil, the DDE concentration may remain unchanged for more than 20 yr. Remediation of DDE-contaminated soil and water may be done by several techniques. Phytoremediation involves translocating DDT, DDD, and DDE from the soil into the plant, although some aquatic species (duckweed > elodea > parrot feather) can transform DDT into predominantly DDD with some DDE being formed. Of all the plants that can uptake DDE, Cucurbita pepo has been the most extensively studied, with translocation values approaching "hyperaccumulation" levels. Soil moisture, temperature, and plant density have all been documented as important factors in the uptake of DDE by Cucurbita pepo. Uptake may also be influenced positively by amendments such as biosurfactants, mycorrhizal inoculants, and low molecular weight organic acids (e.g., citric and oxalic acids). DDE microbial degradation by dehalogenases, dioxygenases, and hydrolases occurs under the proper conditions. Although several aerobic degradation pathways have been proposed, none has been fully verified. Very few aerobic pure cultures are capable of fully degrading DDE to CO2. Cometabolism of DDE by Pseudomonas sp., Alicaligens sp., and Terrabacter sp. grown on biphenyl has been reported; however, not all bacterial species that produce biphenyl dioxygenase degraded DDE. Arsenic and copper inhibit DDE degradation by aerobic microorganisms. Similarly, metal chelates such as EDTA inhibit the

  1. Digestion and degradation, air for life.

    PubMed

    Lettinga, G

    2001-01-01

    Anaerobic degradation of dead biomass is a natural gasification process, an anaerobic crematorium producing a very useful end-product composed of methane and carbon dioxide, generally polluted with small amounts of some malodorous and quite toxic volatile S-compounds. It leads to the production of essential building elements for new life. This exciting field became my faith, vision, hope and expectation. This paper intends to present a reflection of more than three decades of research, teaching and advertisement in the field of sustainable environmental protection technologies, particularly of systems based on anaerobic digestion and the biological sulphur cycle. Considerable progress has been made during these decades worldwide, both in the basic understanding of the various processes and concepts, but also in the implementation of these systems, despite the fact that particularly the implementation frequently proceeded very laboriously. The difficulties certainly can no longer be attributed to technological limitations and/or insufficient understanding of the microbiology and chemistry only, but mainly to the frustrating social rigidity and short-term self-interest in all sectors of our society. By combining anaerobic processes with other microbiological degradation or transformation processes, like those based on the biological sulphur cycle, micro-aerobic and conventional aerobic and anoxic processes, ideal conditions can be created to valorise residues (wastes) from domestic, industrial and agricultural origin. It is simply not just "technology", but also a route to achieve more sustainability and justice in society. It is a fight against conservative establishments. Decomposition, disintegration disbandment, it also stands for deliverance and liberation, space and air for continuation of life.

  2. Degradation of alkanes by bacteria.

    PubMed

    Rojo, Fernando

    2009-10-01

    Pollution of soil and water environments by crude oil has been, and is still today, an important problem. Crude oil is a complex mixture of thousands of compounds. Among them, alkanes constitute the major fraction. Alkanes are saturated hydrocarbons of different sizes and structures. Although they are chemically very inert, most of them can be efficiently degraded by several microorganisms. This review summarizes current knowledge on how microorganisms degrade alkanes, focusing on the biochemical pathways used and on how the expression of pathway genes is regulated and integrated within cell physiology.

  3. Immobilization of microalgae for biosorption and degradation of butyltin chlorides.

    PubMed

    Zhang, L; Huang, G; Yu, Y

    1998-07-01

    Since the discovery of their biocidal properties in the 1950s, organotin compounds have found a large spectrum of industrial applications such as wood and textile preservatives, fungicides and pesticides, and antifouling paint on ships and fishing equipment. The fate and environmental impact of butyltins have been the subjects of a large body of research in the last decades. Biosorption and degradation of butyltin compounds by immobilized microalgae chlorella were studied in this paper, aiming to find an alternative way to solve organotin pollution problem. Chlorella emersonii cells were entrapped in a calcium aginate matrix. The cell growth rates, respiratory rate and chlorophyll a content were studied and compared. Results showed that immobilized chlorella had increased respiratory and growth rates, and almost equal chlorophyll a content when compared with free cells. Cell leakage was slight during the 20-day experimental period Cell leakage from the matrix was unrelated to cell growth within the matrix. Immobilized chlorella was applied to deal with butytin contaminated aquatic solutions. Immobilized chlorella had increased degradation rates of tri-, di-, and mono-butyltin chlorides in aquatic solutions, and lower biological accumulation factors on cells, than free cells, which indicates a potential use for tackleing organotin polluted water body.

  4. Permafrost Degradation and Stream Metabolism in the Arctic: The effect of thaw slump sedimentation on biological productivity and water quality in the Selawik River, Northwest Alaska

    NASA Astrophysics Data System (ADS)

    Calhoun, J. P.; Crosby, B. T.

    2011-12-01

    The Selawik River in northwest Alaska, drains ~12,500 km^2 of tree line spruce forest, upland tundra and lowland wetlands. Along the river corridor, high concentrations of fine sediment from a large, young, active retrogressive thaw slump alter the physical and ecological form and function of the stream. This disturbance impacts the entire downstream river corridor, affecting the viability of fish habitat and quality drinking water that subsistence-based native communities depend on. In anticipated warming scenarios, it can be expected that there will be an increase in both the frequency and magnitude of these permafrost degradation features, increasing the extent to which local villages and ecosystems are affected. Our study aims to improve our physical understanding of this system in order to provide biologists, land managers and city officials improved predictive capabilities. Whole stream metabolism (WSM) combines nutrient cycling and organic matter processing to provide an integrated measure of stream health. We utilized a suite of water quality data including temperature, dissolved oxygen, turbidity, pH, pressure, and conductance to calculate WSM values at two experimental reaches up and downstream of the slump over the past three summers. The immediate effects are large magnitude diurnal increases in turbidity, suppressed dissolved oxygen values, and strong attenuation of photosynthetically active radiation (PAR) with depth. We found from 2010 data that, on average, the waters downstream from the slump were 23 times more turbid, had roughly half the dissolved oxygen, and had 4.7 and 2.7 times lower gross primary production (GPP) and ecosystem respiration (ER) respectively. In the summer of 2011, we collected measurements of terrestrial PAR, subsurface PAR, dissolved oxygen and turbidity at multiple river depths at 5 experimental locations. Though turbidity varied roughly by two orders of magnitude and terrestrial PAR increased 850 times between solar

  5. Biodegradation, bioaccessibility, and genotoxicity of diffuse polycyclic aromatic hydrocarbon (PAH) pollution at a motorway site.

    PubMed

    Johnsen, Anders R; De Lipthay, Julia R; Reichenberg, Fredrik; Sørensen, Søren J; Andersen, Ole; Christensen, Peter; Binderup, Mona-lise; Jacobsen, Carsten S

    2006-05-15

    Diffuse pollution of surface soil with polycyclic aromatic hydrocarbons (PAHs) is problematic in terms of the large areas and volumes of polluted soil. The levels and effects of diffuse PAH pollution at a motorway site were investigated. Surface soil was sampled with increasing distance from the asphalt pavement and tested for total amounts of PAHs, amounts of bioaccessible PAHs, total bacterial populations, PAH degrader populations, the potential for mineralization of 14C-PAHs, and mutagenicity. Elevated PAH concentrations were found in the samples taken 1-8 m from the pavement. Soil sampled at greater distances (12-24 m) contained only background levels of PAHs. The total bacterial populations (CFU and numbers of 16S rDNA genes) were similar for all soil samples, whereas the microbial degrader populations (culturable PAH degraders and numbers of PAH dioxygenase genes) were most abundant in the most polluted samples close to the pavement. Hydroxypropyl-beta-cyclodextrin extraction of soil PAHs, as a direct estimate of the bioaccessibility, indicated that only 1-5% of the PAHs were accessible to soil bacteria. This low bioaccessibility is suggested to be due to sorption to traffic soot particles. The increased PAH level close to the pavement was reflected in slightly increased mutagenic activity (1 m, 0.32 +/- 0.08 revertants g(-1) soil; background/ 24 m: 0.08 +/- 0.04), determined by the Salmonella/ microsome assay of total extractable PAHs activated by liver enzymes. The potential for lighter molecular weight PAH degradation in combination with low bioaccessibility of heavier PAHs is proposed to lead to a likely increase in concentration of heavier PAHs over time. These residues are, however, likely to be of low biological significance.

  6. New approach to optimize operational conditions for the biological treatment of a high-strength thiocyanate and ammonium waste: pH as key factor.

    PubMed

    Lay-Son, Meiling; Drakides, Christian

    2008-02-01

    Biological treatment of coke and steel-processing wastewaters has to satisfy both industrial economic needs and environmental protection regulations. Nevertheless, as some of the pollutants contained in these waters or produced during the treatment are highly toxic, an effective and safe treatment has proved to be difficult to obtain. This paper reports the study of a biological method for the treatment of wastewaters containing free cyanide, thiocyanate and ammonium (NH4). Laboratory-scale activated-sludge reactors were fed with a synthetic solution reproducing a steel-processing industrial wastewater and inoculated with the same industrial bacterial seeding used on-site (Ecosynergie Inc.). The results demonstrated that free cyanide and thiocyanate were efficiently degraded. Nevertheless, thiocyanate degradation and nitrification processes were actually inhibited by the free ammonia form (NH3) in place of the ionized NH4 form (NH4+) currently dosed and often unproperly named "ammonia" [IUPAC, 1997. In: McNaught, A.D., Wilkinson, A. (compilers). Compendium of Chemical Terminology. Royal Society of Chemistry, Cambridge, UK]. Optimum degradation rates were obtained for very narrow ranges of ammonia nitrogen (NH3-N) concentrations. This result can be explained by the role of pH, which mainly controls the NH3/NH4 equilibrium. Pollutants and NH3 concentrations influenced degradation rates of main pollutants. This influence was determined and expressed through elementary equations. Although the Michaelis-Menten equation could have been used to describe thiocyanate degradation, a Haldane-inhibition model was used to satisfactorily describe cyanide degradation. On the other hand, a slightly modified Haldane model was applied to describe both NH4 oxidation using NH3-N as substrate and thiocyanate degradation using NH3-N as inhibitor. These findings emphasize the role of pH on degradation rates and allow one to optimize operational conditions in the biological treatment of

  7. Transformation products of pharmaceuticals in surface waters and wastewater formed during photolysis and advanced oxidation processes - degradation, elucidation of byproducts and assessment of their biological potency.

    PubMed

    Fatta-Kassinos, D; Vasquez, M I; Kümmerer, K

    2011-10-01

    The significance of transformation products of pharmaceuticals resulting from the parent compounds during natural and technical photolytic processes and advanced oxidation processes has only recently started to attract the interest of the scientific community. Even though relevant studies have now started to produce important knowledge, still many gaps exist that hinder the in-depth and broad understanding of the extent of the potential problems stemming from the presence of such compounds in the environment and the applicability of such techniques for wastewater and potable water treatment. The great diversity of pharmaceutical compounds, the variety of processes and conditions applied by the various research groups active in the field, and the endless list of potential biological endpoints that could potentially be explored, coupled with the limitations related to the analytical capabilities presently available, are some of the crucial parameters that characterize this challenging research direction. This review paper tries to highlight some of the most relevant studies performed so far and to summarize the parameters that prevent scientists from reaching comprehensive conclusions in relation to the formation, fate, and effects of transformation products of pharmaceutical compounds during photo-driven and advanced oxidation processes.

  8. Olive plants (Olea europaea L.) as a bioindicator for pollution.

    PubMed

    Eliwa, Amal Mohamed; Kamel, Ehab Abdel-Razik

    2013-06-15

    In the present work, olive plant (Olea europaea L.) was used as a biological indicator for pollution in which, molecular and physiological parameters were studied. Olive plants were collected from polluted and non-polluted areas in Jeddah - Saudi Arabia, traffic area as an air polluted area, sewage treatment station as water polluted area, industrial area as solid waste polluted, costal area as marine polluted area and an area without a direct source of pollution far away from the city center, which was used as control. These changes conducted with nucleic acid content, minerals content, pigments and some growth parameters. Results showed significant reductions in DNA and RNA contents under all polluted sites. Mineral contents were varied widely depending on the different pollutants and locations of olive plant. Generally, micro-elements varied (increase/decrease) significantly within collected samples and the source of pollution. All growth parameters were decreased significantly within the studied samples of all pollutant areas except the relative water content was increased. The content of chlorophyll a has decreased highly significantly in all polluted leaves. While the content of chlorophyll b has increased significantly in all polluted leaves especially in air polluted leaves. The total content of carotenoid pigments has decreased highly significantly in all polluted leaves. It was concluded that olive plant can be used as a biological indicator to the environmental pollutants.

  9. Particle Pollution

    MedlinePlus

    ... Index from the U.S. Environmental Protection Agency (EPA). Air Quality Index (AQI) The EPA Air Quality Index (AQI) tells you when air pollution is ... For more tools to help you learn about air quality, visit Tracking Air Quality . Top of Page File ...

  10. Pollution Solution

    ERIC Educational Resources Information Center

    Vannan, Donald A.

    1972-01-01

    Stresses briefly the need for individuals' actions for controlling the environmental pollution. A number of projects are suggested for teachers to involve children in this area. Simulated discussion groups of sellers'' and consumers, use of pictures, onion juice, and a water filtration contest are a few of the sources used. (PS)

  11. MOLD POLLUTION

    EPA Science Inventory

    Mold pollution is the growth of molds in a building resulting in a negative impact on the use of that structure. The negative impacts generally fall into two categories: destruction of the structure itself and adverse health impacts on the building's occupants. It is estimated...

  12. Water Pollution

    MedlinePlus

    We all need clean water. People need it to grow crops and to operate factories, and for drinking and recreation. Fish and wildlife depend on ... and phosphorus make algae grow and can turn water green. Bacteria, often from sewage spills, can pollute ...

  13. Air pollution.

    PubMed

    Le, Nhu D; Sun, Li; Zidek, James V

    2010-01-01

    Toxic air pollutants are continuously released into the air supply. Various pollutants come from chemical facilities and small businesses, such as automobile service stations and dry cleaning establishments. Others, such as nitrogen oxides, carbon monoxide and other volatile organic chemicals, arise primarily from the incomplete combustion of fossil fuels (coal and petroleum) and are emitted from sources that include car exhausts, home heating and industrial power plants. Pollutants in the atmosphere also result from photochemical transformations; for example, ozone is formed when molecular oxygen or nitrogen interacts with ultraviolet radiation. An association between air pollution exposure and lung cancer has been observed in several studies. The evidence for other cancers is far less conclusive. Estimates of the population attributable risk of cancer has varied substantially over the last 40 years, reflecting the limitations of studies; these include insufficient information on confounders, difficulties in characterizing associations due to a likely lengthy latency interval, and exposure misclassification. Although earlier estimates were less than one percent, recent cohort studies that have taken into account some confounding factors, such as smoking and education amongst others, suggest that approximately 3.6% of lung cancer in the European Union could be due to air pollution exposure, particularly to sulphate and fine particulates. A separate cohort study estimated 5-7% of lung cancers in European never smokers and ex-smokers could be due to air pollution exposure. Therefore, while cigarette smoking remains the predominant risk factor, the proportion of lung cancers attributable to air pollution may be higher than previously thought. Overall, major weaknesses in all air-pollution-and-cancer studies to date have been inadequate characterization of long-term air pollution exposure and imprecise or no measurements of covariates. It has only been in the last

  14. Multistage treatment system for raw leachate from sanitary landfill combining biological nitrification-denitrification/solar photo-Fenton/biological processes, at a scale close to industrial--biodegradability enhancement and evolution profile of trace pollutants.

    PubMed

    Silva, Tânia F C V; Silva, M Elisabete F; Cunha-Queda, A Cristina; Fonseca, Amélia; Saraiva, Isabel; Sousa, M A; Gonçalves, C; Alpendurada, M F; Boaventura, Rui A R; Vilar, Vítor J P

    2013-10-15

    A multistage treatment system, at a scale close to the industrial, was designed for the treatment of a mature raw landfill leachate, including: a) an activated sludge biological oxidation (ASBO), under aerobic and anoxic conditions; b) a solar photo-Fenton process, enhancing the bio-treated leachate biodegradability, with and without sludge removal after acidification; and c) a final polishing step, with further ASBO. The raw leachate was characterized by a high concentration of humic substances (HS) (1211 mg CHS/L), representing 39% of the dissolved organic carbon (DOC) content, and a high nitrogen content, mainly in the form of ammonium nitrogen (>3.8 g NH4(+)-N/L). In the first biological oxidation step, a 95% removal of total nitrogen and a 39% mineralization in terms of DOC were achieved, remaining only the recalcitrant fraction, mainly attributed to HS (57% of DOC). Under aerobic conditions, the highest nitrification rate obtained was 8.2 mg NH4(+)-N/h/g of volatile suspended solids (VSS), and under anoxic conditions, the maximum denitrification rate obtained was 5.8 mg (NO2(-)-N + NO3(-)-N)/h/g VSS, with a C/N consumption ratio of 2.4 mg CH3OH/mg (NO2(-)-N + NO3(-)-N). The precipitation of humic acids (37% of HS) after acidification of the bio-treated leachate corresponds to a 96% DOC abatement. The amount of UV energy and H2O2 consumption during the photo-Fenton reaction was 30% higher in the experiment without sludge removal and, consequently, the reaction velocity was 30% lower. The phototreatment process led to the depletion of HS >80%, of low-molecular-weight carboxylate anions >70% and other organic micropollutants, thus resulting in a total biodegradability increase of >70%. The second biological oxidation allowed to obtain a final treated leachate in compliance with legal discharge limits regarding water bodies (with the exception of sulfate ions), considering the experiment without sludge. Finally, the high efficiency of the overall treatment

  15. Environmental and biological factors controlling the spring phytoplankton bloom at the Patagonian shelf-break front - Degraded fucoxanthin pigments and the importance of microzooplankton grazing

    NASA Astrophysics Data System (ADS)

    Carreto, José I.; Montoya, Nora G.; Carignan, Mario O.; Akselman, Rut; Acha, E. Marcelo; Derisio, Carla

    2016-08-01

    The aim of this study was to investigate the biotic and abiotic factors controlling the spring phytoplankton blooms at the Patagonian shelf-break front (PSBF). Using a CHEMTAX analysis of HPLC pigment data and other methods, the biomass and spatial variability of plankton communities were studied in four sections (39-48°S) across the PSBF during October 2005. Environmental factors and the biomass and composition of plankton communities exhibited a marked spatial heterogeneity. The latitudinal and cross-shelf progression in the timing of the spring bloom initiation and the nutritive properties of the water masses (Subantarctic Shelf Waters and Malvinas Current Waters) seemed to be the key factors. Three plankton regions were distinguished: (a) Outer shelf (OS), (b) Shelf-break front (SBF) and (c) Malvinas Current (MC). At the highly stratified OS region, the post-bloom community showed low-biomasshigh-phytoplankton diversity formed mainly by small cells (haptophytes 30-62%, diatoms 17-49%, chlorophytes 0-34%, and prasinophytes 0-21% of total Chl a). High amounts of degraded fucoxanthin were found associated with the heterotrophic dinoflagellate, Protoperidinium capurroi. Grazing by this microheterotroph on the diatom population seemed to be the most important factor for the spring bloom decay at the OS. A remarkable quasi monospecific bloom (∼90%) of a nanodiatom (Thalassiosira bioculata var. raripora) associated with high Chl a (up to 20 mg m-3) occurred along (∼1000 km) the SBF and in the most northern extension of the MC. In the southern region, the bloom was developed under absent or incipient density stratification, increasing solar irradiance, high nitrate and phosphate availability, and low numbers of phytoplankton grazers. The average mixedlayer PAR irradiance (<2.0 mol quanta PAR m-2 d-1) and Si:N ratios (<0.2) were low, suggesting a diatom population limited by light and under progressive silicate limitation. The more stratified northern region of the

  16. Investigation of heavy metal pollution in eastern Aegean Sea coastal waters by using Cystoseira barbata, Patella caerulea, and Liza aurata as biological indicators.

    PubMed

    Aydın-Önen, S; Öztürk, M

    2017-01-19

    In order to have an extensive contamination profile of heavy metal levels (Cd, Cu, Fe, Mn, Ni, Pb, and Zn), seawater, sediment, Patella caerulea, Cystoseira barbata, and Liza aurata were investigated by using inductively coupled plasma-atomic emission spectrometry (ICP-AES). Samples were collected from five coastal stations along the eastern Aegean Sea coast (Turkey) on a monthly basis from July 2002 through May 2003. According to the results of this study, heavy metal levels were arranged in the following sequence: Fe > Pb > Zn > Mn > Ni > Cu > Cd for water, Fe > Cu > Mn > Ni > Zn > Pb > Cd for sediment, Fe > Zn > Mn > Pb > Ni > Cd > Cu for C. barbata, Fe > Zn > Mn > Ni > Pb > Cu > Cd for P. caerulea, and Fe > Zn > Mn > Cu > Ni > Pb > Cd for L. aurata. Moreover, positive relationships between Fe in water and Mn in water, Fe in sediment and Mn in sediment, Fe in C. barbata and Mn in C. barbata, Fe in P. caerulea and Mn in P. caerulea, and Fe in L. aurata and Mn in L. aurata may suggest that these metals could be originated from the same anthropogenic source. C. barbata represented with higher bioconcentration factor (BCF) values, especially for Fe, Mn, and Zn values. This observation may support that C. barbata can be used as an indicator species for the determinations of Fe, Mn, and Zn levels. Regarding Turkish Food Codex Regulation's residue limits, metal values in L. aurata were found to be lower than the maximum permissible levels issued by Turkish legislation and also the recommended limits set by FAO/WHO guidelines. The results of the investigation indicated that P. caerulea, L. aurata, and especially C. barbata are quantitative water-quality bioindicators and biomonitoring subjects for biologically available metal accumulation for Aegean Sea coastal waters.

  17. Persistent organic pollutants in a marine bivalve on the Marennes-Oléron Bay and the Gironde Estuary (French Atlantic Coast) - part 2: potential biological effects.

    PubMed

    Luna-Acosta, A; Bustamante, P; Budzinski, H; Huet, V; Thomas-Guyon, H

    2015-05-01

    Contaminant effects on defence responses of ecologically and economically important organisms, such as the Pacific oyster Crassostrea gigas, are likely to influence their ability to resist infectious diseases, particularly at the young stages. The aim of this study was to explore the potential relationships between organic contaminants accumulated in the soft tissues of juvenile oysters, defence responses and physiological condition. Oysters were transplanted during summer and winter periods i