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Sample records for pollutants biological degradation

  1. Mixotrophic cyanobacteria and microalgae as distinctive biological agents for organic pollutant degradation.

    PubMed

    Subashchandrabose, Suresh R; Ramakrishnan, Balasubramanian; Megharaj, Mallavarapu; Venkateswarlu, Kadiyala; Naidu, Ravi

    2013-01-01

    Millions of natural and synthetic organic chemical substances are present in both soil and aquatic environments. Toxicity and/or persistence determine the polluting principle of these substances. The biological responses to these pollutants include accumulation and degradation. The responses of environments with organic pollutants are perceptible from the dwindling degradative abilities of microorganisms. Among different biological members, cyanobacteria and microalgae are highly adaptive through many eons, and can grow autotrophically, heterotrophically or mixotrophically. Mixotrophy in cyanobacteria and microalgae can provide many competitive advantages over bacteria and fungi in degrading organic pollutants. Laboratory culturing of strict phototrophic algae has limited the realization of their potential as bioremediation agents. In the natural assemblages, mixotrophic algae can contribute to sequestration of carbon, which is otherwise emitted as carbon dioxide to the atmosphere under heterotrophic conditions by other organisms. Molecular methods and metabolic and genomic information will help not only in identification and selection of mixotrophic species of cyanobacteria and microalgae with capabilities to degrade organic pollutants but also in monitoring the efficiency of remediation efforts under the field conditions. These organisms are relatively easier for genetic engineering with desirable traits. This review presents a new premise from the literature that mixotrophic algae and cyanobacteria are distinctive bioremediation agents with capabilities to sequester carbon in the environment. PMID:23201778

  2. 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.

  3. 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. PMID:12892669

  4. Propane biostimulation in biologically activated carbon (BAC) selects for bacterial clades adept at degrading persistent water pollutants.

    PubMed

    Mikkelson, Kristin M; Homme, Carissa L; Li, Dong; Sharp, Jonathan O

    2015-08-01

    Biologically activated carbon (BAC) can be used in both municipal water and hazardous waste remediation applications to enhance contaminant attenuation in water; however, questions remain about how selective pressures can be applied to increase the capabilities of microbial communities to attenuate recalcitrant contaminants. Here we utilized flow-through laboratory columns seeded with municipally derived BAC and exposed to water from a local drinking water facility to query how propane biostimulation impacts resident microorganisms. Ecological analyses using high throughput phylogenetic sequencing revealed that while propane did not increase the total number of microbiological species, it did select for bacterial communities that were distinct from those without propane. Temporal extractions demonstrated that microbial succession was rapid and established in approximately 2 months. A higher density of propane monooxygenase genes and bacterial clades including the Pelosinus and Dechloromonas genera suggest an enhanced potential for the degradation of persistent water pollutants in propane-stimulated systems. However, the ecological selective pressure was exhausted in less than 15 cm of transit in this flow-through scenario (25 hour retention) indicating a pronounced zonation that could limit the size of a biostimulated zone and require physical mixing, hydraulic manipulation, or other strategies to increase the spatial impact of biostimulation in flow-through scenarios. PMID:26154499

  5. 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. PMID:16740278

  6. 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.

  7. 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,…

  8. 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.

  9. 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).

  10. Database on microbial degradation of soil pollutants

    SciTech Connect

    Gleim, D.; Milch, H.; Kracht, M.

    1995-12-31

    The factual database outlined in this paper has been developed to provide rapid reliable information on the biodegradability of soil pollutants and on possible bioremedial action. It contains information both on degradation in pure and mixed cultures and on degradation in soils. At present the study comprises haloaliphatic compounds, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and polychlorinated dioxins and furans.

  11. 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.

  12. 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.

  13. "Shoot and Sense" Janus Micromotors-Based Strategy for the Simultaneous Degradation and Detection of Persistent Organic Pollutants in Food and Biological Samples.

    PubMed

    Rojas, D; Jurado-Sánchez, B; Escarpa, A

    2016-04-01

    A novel Janus micromotor-based strategy for the direct determination of diphenyl phthalate (DPP) in food and biological samples is presented. Mg/Au Janus micromotors are employed as novel analytical platforms for the degradation of the non-electroactive DPP into phenol, which is directly measured by difference pulse voltammetry on disposable screen-printed electrodes. The self-movement of the micromotors along the samples result in the generation of hydrogen microbubbles and hydroxyl ions for DPP degradation. The increased fluid transport improves dramatically the analytical signal, increasing the sensitivity while lowering the detection potential. The method has been successfully applied to the direct analysis of DPP in selected food and biological samples, without any sample treatment and avoiding any potential contamination from laboratory equipment. The developed approach is fast (∼5 min) and accurate with recoveries of ∼100%. In addition, efficient propulsion of multiple Mg/Au micromotors in complex samples has also been demonstrated. The advantages of the micromotors-assisted technology, i.e., disposability, portability, and the possibility to carry out multiple analysis simultaneously, hold considerable promise for its application in food and biological control in analytical applications with high significance. PMID:26938969

  14. 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.

  15. 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.

  16. ADSORPTION, MOVEMENT, AND BIOLOGICAL DEGRADATION OF LARGE CONCENTRATIONS OF SELECTED PESTICIDES IN SOILS

    EPA Science Inventory

    Because of the importance of soil in biologically reducing the quantity and retarding the rate of pollutant movement into groundwater, this laboratory study was initiated to evaluate the adsorption, mobility, and degradation of large concentrations of the pesticide atrazine, meth...

  17. Mobilization of Pollutant-Degrading Bacteria by Eukaryotic Zoospores.

    PubMed

    Sungthong, Rungroch; van West, Pieter; Heyman, Fredrik; Jensen, Dan Funck; Ortega-Calvo, Jose Julio

    2016-07-19

    The controlled mobilization of pollutant-degrading bacteria has been identified as a promising strategy for improving bioremediation performance. We tested the hypothesis whether the mobilization of bacterial degraders may be achieved by the action of eukaryotic zoospores. We evaluated zoospores that are produced by the soil oomycete Pythium aphanidermatum as a biological vector, and, respectively, the polycyclic aromatic hydrocarbon (PAH)-degrading bacteria Mycobacterium gilvum VM552 and Pseudomonas putida G7, acting as representative nonflagellated and flagellated species. The mobilization assay was performed with a chemical-in-capillary method, in which zoospores mobilized bacterial cells only when they were exposed to a zoospore homing inducer (5% (v/v) ethanol), which caused the tactic response and settlement of zoospores. The mobilization was strongly linked to a lack of bacterial motility, because the nonflagellated cells from strain M. gilvum VM552 and slightly motile, stationary-phase cells from P. putida G7 were mobilized effectively, but the actively motile, exponentially grown cells of P. putida G7 were not mobilized. The computer-assisted analysis of cell motility in mixed suspensions showed that the swimming rate was enhanced by zoospores in stationary, but not in exponentially grown, cells of P. putida G7. It is hypothesized that the directional swimming of zoospores caused bacterial mobilization through the thrust force of their flagellar propulsion. Our results suggest that, by mobilizing pollutant-degrading bacteria, zoospores can act as ecological amplifiers for fungal and oomycete mycelial networks in soils, extending their potential in bioremediation scenarios. PMID:27286642

  18. 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...

  19. Engineering dioxygenases for efficient degradation of environmental pollutants.

    PubMed

    Furukawa, K

    2000-06-01

    Dioxygenases have recently been engineered to improve their capabilities for environmental pollutant degradation. The techniques used to achieve this include in vitro DNA shuffling and subunit or domain exchanges between dioxygenases of different bacterial origins. Such evolved enzymes acquire novel and enhanced degradation capabilities of xenobiotic compounds, such as polychlorinated biphenyls, trichloroethylene and a variety of aromatic compounds. Hybrid strains in which the evolved genes are integrated into the chromosomal operons exhibit efficient degradation of xenobiotic chlorinated compounds. PMID:10851151

  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. Biological degradation of TNT-contaminated soil

    SciTech Connect

    Manning, J.F.; Boopathy, R.

    1995-12-31

    The concept of using biological slurry reactors to remediate soil contaminated with TNT has been investigated at the laboratory scale. Important parameters include an organic co-substrate and appropriate amounts of nitrogen and phosphorus added as nutrients. Normally, the degradation requires an organic co-substrate. The type of co-substrate can have a significant impact on the rate and extent of degradation. Succinate, malate, molasses, and glucose are all acceptable co-substrates. Molasses, or succinate with added yeast extract and/or peptone, provides superior rates of removal. Consortia of microorganisms isolated from various sites can also degrade TNT. To exploit the microbial system, laboratory scale soil slurry reactors have been operated, achieving reductions in TNT concentrations on the order of 90-99% from initial TNT concentrations of 7,000-10,000 mg/kg. Laboratory scale tests have shown that all of the intermediates can be removed by microbial degradation. Laboratory reactors operated with 15% volume replacement one, two, or three times a week achieved removal of 95-99% of the TNT in the feed soil. This system can reduce TNT concentrations to less than 20 mg/kg in treated soil. In particular, operation of the reactors in an aerobic-anoxic sequenced pattern promotes the conversion of TNT to CO{sub 2} and microbial biomass. Radiolabeling studies demonstrated that 50% of the TNT is mineralized, with 30% of the original labeled TNT being converted to microbial biomass. To take advantage of this technology, a field demonstration in which the soil slurry reactor is being used to degrade explosives-contaminated soil is currently being conducted.

  2. Application of nano filter for organic pollutant degradation

    NASA Astrophysics Data System (ADS)

    Qandalee, Mohammad; Hatami, Mehdi; Majedi, Ali; Bateni, Mohsen; Vahdat, Seyed Mohammad

    2012-12-01

    In this study, the possibility of using a novel nanocomposite structure based on nanoscale titanium dioxide as a filter toward elimination of organic pollutant was investigated. Methyl Orange (MO) was selected as a typical organic pollutant and effect of lamp intensity, addition of hydrogen peroxide and MO concentration were investigated. The photocatalytic degradation of MO was modeled using Langmuir-Hinshelwood equation and the removal rates were simulated.

  3. Metagenomics for the discovery of pollutant degrading enzymes.

    PubMed

    Ufarté, Lisa; Laville, Élisabeth; Duquesne, Sophie; Potocki-Veronese, Gabrielle

    2015-12-01

    Organic pollutants, including xenobiotics, are often persistent and toxic organic compounds resulting from human activities and released in large amounts into terrestrial, fluvial and marine environments. However, some microbial species which are naturally exposed to these compounds in their own habitat are capable of degrading a large range of pollutants, especially poly-aromatic, halogenated and polyester molecules. These microbes constitute a huge reservoir of enzymes for the diagnosis of pollution and for bioremediation. Most are found in highly complex ecosystems like soils, activated sludge, compost or polluted water, and more than 99% have never been cultured. Meta-omic approaches are thus well suited to retrieve biocatalysts from these environmental samples. In this review, we report the latest advances in functional metagenomics aimed at the discovery of enzymes capable of acting on different kinds of polluting molecules. PMID:26526541

  4. 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.

  5. BIOLOGICAL APPROACHES FOR POLYCHLORINATED BIPHENYL DEGRADATION

    EPA Science Inventory

    In summary, it will be important in the future to evaluate genetically engineered PCB-degradative strains for their ability to degrade PCBs as actually found in the environment. his integration of genetic and soil studies is a logical and practical extension of important and prom...

  6. 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

  7. 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…

  8. Optical thickness as related to pollutant episodes and the concentration of visibility degrading pollutants

    NASA Technical Reports Server (NTRS)

    Prospero, J. M.; Savoie, D.; Snowdon, T.; Ewbank, P.

    1983-01-01

    A network of six sun photometers was placed in the central and northeast United States during the months of July through October, 1931. The objective of the program was to obtain measurements of atmospheric turbidity which can be related to the concentration of visibility-degrading pollutants in the atmosphere. These measurements serve as ground truth for a program to develop remote sensing techniques for measuring the vertically integrated aerosol concentrations in pollution episodes. The sun photometers measure the direct solar radiation in four passbands: 380 nm, 500 nm, 875 nm and 940 nm. The first three passbands will be used for measuring the aerosol optical depth and the last for measuring precipitable water.

  9. Role of Ubiquitin-Mediated Degradation System in Plant Biology.

    PubMed

    Sharma, Bhaskar; Joshi, Deepti; Yadav, Pawan K; Gupta, Aditya K; Bhatt, Tarun K

    2016-01-01

    Ubiquitin-mediated proteasomal degradation is an important mechanism to control protein load in the cells. Ubiquitin binds to a protein on lysine residue and usually promotes its degradation through 26S proteasome system. Abnormal proteins and regulators of many processes, are targeted for degradation by the ubiquitin-proteasome system. It allows cells to maintain the response to cellular level signals and altered environmental conditions. The ubiquitin-mediated proteasomal degradation system plays a key role in the plant biology, including abiotic stress, immunity, and hormonal signaling by interfering with key components of these pathways. The involvement of the ubiquitin system in many vital processes led scientists to explore more about the ubiquitin machinery and most importantly its targets. In this review, we have summarized recent discoveries of the plant ubiquitin system and its involvement in critical processes of plant biology. PMID:27375660

  10. Role of Ubiquitin-Mediated Degradation System in Plant Biology

    PubMed Central

    Sharma, Bhaskar; Joshi, Deepti; Yadav, Pawan K.; Gupta, Aditya K.; Bhatt, Tarun K.

    2016-01-01

    Ubiquitin-mediated proteasomal degradation is an important mechanism to control protein load in the cells. Ubiquitin binds to a protein on lysine residue and usually promotes its degradation through 26S proteasome system. Abnormal proteins and regulators of many processes, are targeted for degradation by the ubiquitin-proteasome system. It allows cells to maintain the response to cellular level signals and altered environmental conditions. The ubiquitin-mediated proteasomal degradation system plays a key role in the plant biology, including abiotic stress, immunity, and hormonal signaling by interfering with key components of these pathways. The involvement of the ubiquitin system in many vital processes led scientists to explore more about the ubiquitin machinery and most importantly its targets. In this review, we have summarized recent discoveries of the plant ubiquitin system and its involvement in critical processes of plant biology. PMID:27375660

  11. Influence of mussel biological variability on pollution biomarkers.

    PubMed

    González-Fernández, Carmen; Albentosa, Marina; Campillo, Juan A; Viñas, Lucía; Fumega, José; Franco, Angeles; Besada, Victoria; González-Quijano, Amelia; Bellas, Juan

    2015-02-01

    This study deals with the identification and characterization of biological variables that may affect some of the biological responses used as pollution biomarkers. With this aim, during the 2012 mussel survey of the Spanish Marine Pollution monitoring program (SMP), at the North-Atlantic coast, several quantitative and qualitative biological variables were measured (corporal and shell indices, gonadal development and reserves composition). Studied biomarkers were antioxidant enzymatic activities (CAT, GST, GR), lipid peroxidation (LPO) and the physiological rates integrated in the SFG biomarker (CR, AE, RR). Site pollution was considered as the chemical concentration in the whole tissues of mussels. A great geographical variability was observed for the biological variables, which was mainly linked to the differences in food availability along the studied region. An inverse relationship between antioxidant enzymes and the nutritional status of the organism was evidenced, whereas LPO was positively related to nutritional status and, therefore, with higher metabolic costs, with their associated ROS generation. Mussel condition was also inversely related to CR, and therefore to SFG, suggesting that mussels keep an "ecological memory" from the habitat where they have been collected. No overall relationship was observed between pollution and biomarkers, but a significant overall effect of biological variables on both biochemical and physiological biomarkers was evidenced. It was concluded that when a wide range of certain environmental factors, as food availability, coexist in the same monitoring program, it determines a great variability in mussel populations which mask the effect of contaminants on biomarkers. PMID:25483414

  12. 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.

  13. 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)

  14. 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.

  15. 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.

  16. 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.

  17. ROLE OF FUNGAL LIGNINOLYTIC ENZYMES IN POLLUTANT DEGRADATION

    EPA Science Inventory

    Lignin-degrading fungi have potential applications in programs for organopollutant biotreatment. he metabolic pathways that they employ for ligninolysis appear to have unusual xenobiotic capabilities, and there is some preliminary evidence that their extracellular lignin peroxida...

  18. 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.

  19. 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. PMID:17118539

  20. Photochemical and biological degradation of water-soluble FWAs.

    PubMed

    Guglielmetti, L

    1975-01-01

    A study was made of the photochemical and biological degradation of two water-soluble fluorescent whitening agents (FWAs): the disodium 4,4'-bis(2-sulfostyryl)-biphenyl (1) and the disodium 4,4-bis ([4-anilino-6-(N-methyl-N-2-hydroxyethyl)amino 1,3,5-triazin-2-yl]amino)stilbene-2,2'-disulfonate (2). Each represents an important class of detergent fluorescent whitening agents. The photochemical degradation of (1) was studied by irradiating diluted aqueous solutions of this compound with a low intensity high pressure mercury vapor lamp. From the intermediate, as well as the ultimate photodegradation products isolated, it can be infered that photodegradation of (1) followed the proposed scheme. The biologica degradation of (1) and (2) by activated sludge under aerobic conditions was studied using equipment similar to that proposed by the OECD for determining the biodegradation of anionic synthetic surface active agents. Under the conditons applied, both FWAs were slowly biodegraded, within 30 days, whereas the photodegradation products of (1) were completely biodegraded within 14 days. PMID:6265

  1. [The distribution and natural degradation of cyanide in goldmine waste-solid and polluted soil].

    PubMed

    Li, S; Zheng, B; Zhu, J; Wang, B

    2001-05-01

    The farmland and river were seriously polluted by cyanide because one goldmine tailing dam collapsed in 1995. 3 and 4 years after the accident, the cyanide distribution in the polluted farmland and the abandoned tailing dam was studied. The results indicated that natural degradation of cyanide in soil section was slower than in natural water body. The cyanide transference in soil section was similar to freely soluble salts. In arid and semiarid area, cyanide can be highly enriched in the salt shell which content degrading 4 years even higher than the fresh tailing slurry. One side the viscidity layer in the soil section can partly prevent cyanide transference to groundwater, on the other side the result can cause the cyanide highly enrich in the viscidity layer. According to character of cyanide natural degradation in soil the measurement of prevention and cure soil pollution by goldmine tailing dam collapsing was brought forward. PMID:11507898

  2. 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.

  3. Bacterial degradation of naproxen--undisclosed pollutant in the environment.

    PubMed

    Wojcieszyńska, Danuta; Domaradzka, Dorota; Hupert-Kocurek, Katarzyna; Guzik, Urszula

    2014-12-01

    The presence of non-steroidal anti-inflammatory drugs (NSAIDs) in the environment is an emerging problem due to their potential influence on human health and biocenosis. This is the first report on the biotransformation of naproxen, a polycyclic NSAID, by a bacterial strain. Stenotrophomonas maltophilia KB2 transformed naproxen within 35 days with about 28% degradation efficiency. Under cometabolic conditions with glucose or phenol as a carbon source degradation efficiency was 78% and 40%, respectively. Moreover, in the presence of naproxen phenol monooxygenase, naphthalene dioxygenase, hydroxyquinol 1,2-dioxygenase and gentisate 1,2-dioxygenase were induced. This suggests that degradation of naproxen occurs by its hydroxylation to 5,7,8-trihydroxynaproxen, an intermediate that can be cleaved by hydroxyquinol 1,2-dioxygenase. The cleavage product is probably further oxidatively cleaved by gentisate 1,2-dioxygenase. The obtained results provide the basis for the use of cometabolic systems in the bioremediation of polycyclic NSAID-contaminated environments. PMID:25026371

  4. Photoactive chitosan: A step towards a green strategy for pollutant degradation

    PubMed Central

    Walalawela, Niluksha; Greer, Alexander

    2014-01-01

    This article is a highlight of the paper by Ferrari et al. in this issue of Photochemistry and Photobiology. It describes the innovative use of rose bengal-conjugated chitosan as a reusable green catalyst that photo-degrades phenolic compounds in aqueous media, and thereby has decontamination potential of polluted waters. Whether a next-generation photoactive polymer that produces singlet oxygen is a solution to pollutant degradation can be argued. It is as yet unclear what polymeric sensitizer would be practical on a large scale. Nonetheless pursuing this goal is worthwhile. PMID:25270888

  5. Radiation Induced Degradation of Organic Pollutants in Waters and Wastewaters.

    PubMed

    Wojnárovits, László; Takács, Erzsébet

    2016-08-01

    In water treatment by ionizing radiation, and also in other advanced oxidation processes, the main goal is to destroy, or at least to deactivate harmful water contaminants: pharmaceutical compounds, pesticides, surfactants, health-care products, etc. The chemical transformations are mainly initiated by hydroxyl radicals, and the reactions of the formed carbon centered radicals with dissolved oxygen basically determine the rate of oxidation. The concentration of the target compounds is generally very low as compared to the concentration of such natural 'impurities' as chloride and carbonate/bicarbonate ions or the dissolved humic substances (generally referred to as dissolved organic carbon), which consume the majority of the hydroxyl radicals. The different constituents compete for reacting with radicals initiating the degradation. This manuscript discusses the radiation chemistry of this complex system. It includes the reactions of the primary water radiolysis intermediates (hydroxyl radical, hydrated electron/hydrogen atom), the reactions of radicals that form in radical transfer reactions (dichloride-, carbonate- and sulfate radical anions) and also the contribution to the degradation of organic compounds of such additives as hydrogen peroxide, ozone or persulfate. PMID:27573402

  6. 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.

  7. Arsenite oxidation-enhanced photocatalytic degradation of phenolic pollutants on platinized TiO2.

    PubMed

    Kim, Jaesung; Kim, Jungwon

    2014-11-18

    The effect of As(III) on the photocatalytic degradation of phenolic pollutants such as 4-chlorophenol (4-CP) and bisphenol A (BPA) in a suspension of platinized TiO2 (Pt/TiO2) was investigated. In the presence of As(III), the photocatalytic degradation of 4-CP and BPA was significantly enhanced, and the simultaneous oxidation of As(III) to As(V) was also achieved. This positive effect of As(III) on the degradation of phenolic pollutants is attributed to the adsorption of As(V) (generated from As(III) oxidation) on the surface of Pt/TiO2, which facilitates the production of free OH radicals ((•)OHf) that are more reactive than surface-bound OH radicals ((•)OHs) toward phenolic pollutants. The generation of (•)OHf was indirectly verified by using coumarin as an OH radical trapper and comparing the yields of coumarin--OH adduct (i.e., 7-hydroxycoumarin) formed in the absence and presence of As(V). In repeated cycles of 4-CP degradation, the degradation efficiency of 4-CP gradually decreased in the absence of As(III), whereas it was mostly maintained in the presence of As(III), which was either initially present or repeatedly injected at the beginning of each cycle. The positive effect of As(III) on 4-CP degradation was observed over a wide range of As(III) concentrations (up to mM levels) with Pt/TiO2. However, a high concentration of As(III) (hundreds of μM) inhibited the degradation of 4-CP with bare TiO2. Therefore, Pt/TiO2 can be proposed as a practical photocatalyst for the simultaneous oxidation of phenolic pollutants and As(III) in industrial wastewaters. PMID:25329010

  8. Photocatalytic degradation of agricultural N-heterocyclic organic pollutants using immobilized nanoparticles of titania.

    PubMed

    Mahmoodi, Niyaz Mohammad; Arami, Mokhtar; Limaee, Nargess Yousefi; Gharanjig, Kamaladin

    2007-06-25

    Degradation and mineralization of two agricultural organic pollutants (Diazinon and Imidacloprid as N-heterocyclic aromatics) in aqueous solution by nanophotocatalysis using immobilized titania nanoparticles were investigated. Insecticides, Diazinon and Imidacloprid, are persistent pollutants in agricultural soil and watercourses. A simple and effective method was developed to immobilization of titania nanoparticles. UV-vis, ion chromatography (IC) and chemical oxygen demand (COD) analyses were employed. The effects of operational parameters such as H(2)O(2) and inorganic anions (NO(3)(-), Cl(-) and SO(4)(2-)) were investigated. The mineralization of Diazinon and Imidacloprid was evaluated by monitoring of the formed inorganic anions. The selected pollutants are effectively degraded following first order kinetics model. Results show that the nanophotocatalysis using immobilized titania nanoparticle is an effective method for treatment Diazinon and Imidacloprid from contaminated water. PMID:17145132

  9. 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.

  10. Aquifer microcosms and in situ methods to test the fate and function of pollutant-degrading microorganisms

    SciTech Connect

    Krumme, M.L.; Dwyer, D. . Inst. fuer Biotechnologie); Thiem, S.M.; Tiedje, J.M. ); Smith, R.L. )

    1990-01-01

    Little information is available on groundwater microorganism ecology, and specifically on the distribution and biochemical diversity of pollution degrading microorganisms in the aquifer. While the introduction of nutrients and electron acceptors may stimulate natural populations to degrade certain pollutants, low levels of pollutants and complex mixtures of pollutants may require the modification of natural populations through selective pressure or by means of genetic engineering. This study was designed to address these issues by examining three populations of substituted aromatic compound-degraders: an indigenous population, an introduced degrader, and a genetically engineered microorganism (GEM) in the environmental conditions of a sand and gravel aquifer. The goals of this study are to gain field experience on the fate and function of pollutant-degrading organisms in the aquifer and to evaluate column microcosms and survival chambers as tools for predicting the fate and function of selected and modified bacterial strains as appropriate aquifer bioremediation agents. 6 figs.

  11. 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

  12. A stable isotope model for combined source apportionment and degradation quantification of environmental pollutants

    NASA Astrophysics Data System (ADS)

    Lutz, Stefanie; Van Breukelen, Boris

    2014-05-01

    Natural attenuation can represent a complementary or alternative approach to engineered remediation of polluted sites. In this context, compound specific stable isotope analysis (CSIA) has proven a useful tool, as it can provide evidence of natural attenuation and assess the extent of in-situ degradation based on changes in isotope ratios of pollutants. Moreover, CSIA can allow for source identification and apportionment, which might help to identify major emission sources in complex contamination scenarios. However, degradation and mixing processes in aquifers can lead to changes in isotopic compositions, such that their simultaneous occurrence might complicate combined source apportionment (SA) and assessment of the extent of degradation (ED). We developed a mathematical model (stable isotope sources and sinks model; SISS model) based on the linear stable isotope mixing model and the Rayleigh equation that allows for simultaneous SA and quantification of the ED in a scenario of two emission sources and degradation via one reaction pathway. It was shown that the SISS model with CSIA of at least two elements contained in the pollutant (e.g., C and H in benzene) allows for unequivocal SA even in the presence of degradation-induced isotope fractionation. In addition, the model enables precise quantification of the ED provided degradation follows instantaneous mixing of two sources. If mixing occurs after two sources have degraded separately, the model can still yield a conservative estimate of the overall extent of degradation. The SISS model was validated against virtual data from a two-dimensional reactive transport model. The model results for SA and ED were in good agreement with the simulation results. The application of the SISS model to field data of benzene contamination was, however, challenged by large uncertainties in measured isotope data. Nonetheless, the use of the SISS model provided a better insight into the interplay of mixing and degradation

  13. 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

    2016-06-01

    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. PMID:26937869

  14. Degradation of persistent organic pollutants by Fenton's reagent facilitated by microwave or high-intensity ultrasound.

    PubMed

    Cravotto, G; di Carlo, S; Tumiatti, V; Roggero, C; Bremner, H D

    2005-07-01

    Microwave (MW) and high-intensity ultrasound (US) have emerged as powerful techniques for the elimination of persistent organic pollutants (POPs) that constitute a major health hazard, whether by direct exposure or through accumulation in biota. In order to achieve decontamination, POPs should be completely mineralized to CO2, H2O and smaller amounts of inorganic ions, or at least converted to less harmful chemical species. Under US or MW irradiation rapid degradation of aromatic halides, halogenated phenols and polychlorinated biphenyls in polluted waters was achieved at neutral pH in the presence of a moderate excess (5-30 eq) of Fenton's reagent. Acidification with acetic acid (pH 2.0-2.3) did not affect the process, but sulphuric acid (pH 1.7-2.0) facilitated complete degradation. Thus, compared to conventional methods, US and MW processes are faster and much more efficient. PMID:16080327

  15. 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

  16. Physiologically based pharmacokinetic (PB-PK) modeling of indoor air pollutant degradation by houseplants

    SciTech Connect

    Smith, E.K.; El-Masri, H.A.; Tessari, J.D.; Yang, R.S.H.; Reardon, K.F.

    1994-12-31

    In the US, indoor air pollutant levels commonly exceed outdoor levels by a factor of 7 or more. Since people typically spend more than 90% percent of their time indoors, indoor air pollution has the potential for greater consequences on human health. A NASA researcher has reported that certain houseplants will reduce closed chamber concentrations of common indoor air pollutants by more than 75%. The authors are expanding this research; common houseplants and PB-PK modeling can be combined to predict the reduction rates of frequently detected indoor air pollutants, and be used as an environmental remediation approach. The approach to measuring plant gas uptake of indoor air pollutants provides a more quantitative and controlled approach than previous studies. Construction of the closed chamber system linked to a computerized gas chromatograph is complete. This system measures plant uptake of volatile organic chemicals. In experiments using initial concentrations of 21--2,100 ppm of the common indoor air pollutant trichloroethylene (TCE) with peace lily in soil, between 27--34% of TCE was removed during a 12-hour test period. In similar experiments, plants in abiotic potting media removed only 4--13% of TCE from the closed system, suggesting that microbial degradation or soil adsorption of TCE are significant factors.

  17. Uncertainty in degradation rates for organic micro-pollutants during full-scale sewage sludge composting.

    PubMed

    Sadef, Yumna; Poulsen, Tjalfe G; Habib, Kashif; Iqbal, Tariq; Nizami, Abdul Sattar

    2016-10-01

    Composting can potentially remove organic pollutants in sewage sludge. When estimating pollutant removal efficiency, knowledge of estimate uncertainty is important for understanding estimate reliability. In this study the uncertainty (coefficient of variation, CV) in pollutant degradation rate (K1) and relative concentration at 35days of composting (C35/C0) was evaluated. This was done based on recently presented pollutant concentration data, measured under full-scale composting conditions using two different sampling methods for a range of organic pollutants commonly found in sewage sludge. Non-parametric statistical procedures were used to estimate CV values for K1 and C35/C0 for individual pollutants. These were then used to compare the two sampling methods with respect to CV and to determine confidence intervals for average CV. Results showed that sampling method is crucial for reducing uncertainty. The results further indicated that it is possible to achieve CV values for both K1 and C35/C0 of about 15%. PMID:27342191

  18. Comparison of sensitivity analysis methods for pollutant degradation modelling: a case study from drinking water treatment.

    PubMed

    Neumann, Marc B

    2012-09-01

    Five sensitivity analysis methods based on derivatives, screening, regression, variance decomposition and entropy are introduced, applied and compared for a model predicting micropollutant degradation in drinking water treatment. The sensitivity analysis objectives considered are factors prioritisation (detecting important factors), factors fixing (detecting non-influential factors) and factors mapping (detecting which factors are responsible for causing pollutant limit exceedances). It is shown how the applicability of methods changes in view of increasing interactions between model factors and increasing non-linearity between the model output and the model factors. A high correlation is observed between the indices obtained for the objectives factors prioritisation and factors mapping due to the positive skewness of the probability distributions of the predicted residual pollutant concentrations. The entropy-based method which uses the Kullback-Leibler divergence is found to be particularly suited when assessing pollutant limit exceedances. PMID:22842753

  19. 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

  20. 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. PMID:25912531

  1. Allochthonous bioaugmentation in ex situ treatment of crude oil-polluted sediments in the presence of an effective degrading indigenous microbiome.

    PubMed

    Fodelianakis, S; Antoniou, E; Mapelli, F; Magagnini, M; Nikolopoulou, M; Marasco, R; Barbato, M; Tsiola, A; Tsikopoulou, I; Giaccaglia, L; Mahjoubi, M; Jaouani, A; Amer, R; Hussein, E; Al-Horani, F A; Benzha, F; Blaghen, M; Malkawi, H I; Abdel-Fattah, Y; Cherif, A; Daffonchio, D; Kalogerakis, N

    2015-04-28

    Oil-polluted sediment bioremediation depends on both physicochemical and biological parameters, but the effect of the latter cannot be evaluated without the optimization of the former. We aimed in optimizing the physicochemical parameters related to biodegradation by applying an ex-situ landfarming set-up combined with biostimulation to oil-polluted sediment, in order to determine the added effect of bioaugmentation by four allochthonous oil-degrading bacterial consortia in relation to the degradation efficiency of the indigenous community. We monitored hydrocarbon degradation, sediment ecotoxicity and hydrolytic activity, bacterial population sizes and bacterial community dynamics, characterizing the dominant taxa through time and at each treatment. We observed no significant differences in total degradation, but increased ecotoxicity between the different treatments receiving both biostimulation and bioaugmentation and the biostimulated-only control. Moreover, the added allochthonous bacteria quickly perished and were rarely detected, their addition inducing minimal shifts in community structure although it altered the distribution of the residual hydrocarbons in two treatments. Therefore, we concluded that biodegradation was mostly performed by the autochthonous populations while bioaugmentation, in contrast to biostimulation, did not enhance the remediation process. Our results indicate that when environmental conditions are optimized, the indigenous microbiome at a polluted site will likely outperform any allochthonous consortium. PMID:25621834

  2. 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.

  3. The impact of different reference panels on spectral reflectance coefficients of some biological water pollutants

    NASA Astrophysics Data System (ADS)

    Jenerowicz, Agnieszka; Walczykowski, Piotr

    2015-10-01

    Monitoring of water environment and ecosystem, detecting water contaminants and understanding water quality parameters are most important tasks in water management and protection of whole aquatic environment. Detection of biological contaminants play a very important role in preserving human health and water management. To obtain accurate and precise results of determination of the level of biological contamination and to distinguish its type it is necessary to determine precisely spectral reflectance coefficients of several water biological pollutants with inter alia spectroradiometer. This paper presents a methodology and preliminary results of acquisition of spectral reflectance coefficients with different reference panels (e.g. with 5%, 20%, 50%, 80% and 96% of reflectivity) of several biological pollutants. The authors' main task was to measure spectral reflectance coefficients of different biological water pollutants with several reference panels and to select optimal reference standard, which would allow for distinguish different types of several biological contaminants. Moreover it was necessary to indicate the spectral range in which it is possible to discriminate investigated samples of biological contaminants. By conducting many series of measurements of several samples of different types of biological pollutants, authors had concluded how the reflectivity of reference panel influences the accuracy of acquisition of spectral reflectance coefficients. This research was crucial in order to be able to distinguish several types of biological pollutants and to determine the useful spectral range for detection of different kinds of biological contaminants with multispectral and hyperspectral imagery.

  4. 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

    2016-10-01

    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. PMID:27214000

  5. 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.

  6. Destination of organic pollutants during electrochemical oxidation of biologically-pretreated dye wastewater using boron-doped diamond anode.

    PubMed

    Zhu, Xiuping; Ni, Jinren; Wei, Junjun; Xing, Xuan; Li, Hongna

    2011-05-15

    Electrochemical oxidation of biologically-pretreated dye wastewater was performed in a boron-doped diamond (BDD) anode system. After electrolysis of 12h, the COD was decreased from 532 to 99 mg L(-1) (<100 mg L(-1), the National Discharge Standard of China). More importantly, the destination of organic pollutants during electrochemical oxidation process was carefully investigated by molecular weight distribution measurement, resin fractionation, ultraviolet-visible spectroscopy, HPLC and GC-MS analysis, and toxicity test. As results, most organic pollutants were completely removed by electrochemical oxidation and the rest was primarily degraded to simpler compounds (e.g., carboxylic acids and short-chain alkanes) with less toxicity, which demonstrated that electrochemical oxidation of biologically-pretreated dye wastewater with BDD anode was very effective and safe. Especially, the performance of BDD anode system in degradation of large molecular organics such as humic substances makes it very promising in practical applications as an advanced treatment of biologically-pretreated wastewaters. PMID:21377794

  7. FINAL REPORT. CONTROL OF BIOLOGICALLY ACTIVE DEGRADATION ZONES BY VERTICAL HETEROGENEITY: APPLICATIONS IN FRACTURED MEDIA

    EPA Science Inventory

    The key objective of this research was to determine the distribution of biologically active contaminant degradation zones in a fractured, subsurface medium with respect to vertical heterogeneities. Our expectation was that
    hydrogeological properties would determine the size, d...

  8. 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

  9. A review on sonoelectrochemical technology as an upcoming alternative for pollutant degradation.

    PubMed

    Thokchom, Binota; Pandit, Aniruddha B; Qiu, Pengpeng; Park, Beomguk; Choi, Jongbok; Khim, Jeehyeong

    2015-11-01

    Sonoelectrochemical process has emerged as a novel integrated technology for various applications starting from sonoelectroplating till the remediation of a wide range of contaminants. Although a promising new technology, the application of sonoelectrochemical technology for pollutant degradation are mostly on a laboratory scale, utilizing the conventional reactor configuration of the electrolytic vessel and ultrasonic horns dipped in it. This type of configuration has been believed to be responsible for its sluggish evolution with lower reproducibility, scale-up and design aspects. To achieve a major turn with an enhanced synergy, refinements in the form of optimizing the co-ordination of the governing parameters of both the technologies (e.g., power, frequency, liquid height, electrode material, electrode size, electrode gap, applied voltage, current density etc.) have been validated. Besides, in order to supplement knowledge in the already existing pool, rigorous research on the past and present status has been done. Challenges were also identified and to overcome them, critical discussions covering an overview of the progressive developments on combining the two technologies and its major applications on pollutant degradation were conducted. PMID:26186839

  10. Photocatalytic activity of porous multiwalled carbon nanotube-TiO2 composite layers for pollutant degradation.

    PubMed

    Zouzelka, Radek; Kusumawati, Yuly; Remzova, Monika; Rathousky, Jiri; Pauporté, Thierry

    2016-11-01

    TiO2 nanoparticles are suitable building blocks nanostructures for the synthesis of porous functional thin films. Here we report the preparation of films using brookite, P25 titania and anatase pristine nanoparticles and of nanocomposite layers combining anatase nanoparticles and multi-walled carbon nanotube (MWCNT) at various concentrations. The structure and phase composition of the layers were characterized by X-ray diffraction and Raman spectroscopy. Their morphology and texture properties were determined by scanning electron microscopy and krypton adsorption experiments, respectively. Additionally to a strong absorption in the UV range, the composites exhibited light absorption in the visible range as well. The photocatalytic performance of the layers was tested in the degradation of aqueous solutions of 4-chlorophenol serving as a model of an eco-persistent pollutant. Besides the determination of the decrease in the concentration of 4-chlorophenol, also the formation of intermediate degradation products, namely hydroquinone and benzoquinone, was followed. The presence of MWCNTs had a beneficial effect on the photocatalytic performance, a marked increase in the photocatalytic degradation rate constant being observed even at very low concentrations of MWCNTs. Compared to a P25 reference layer, the first order rate reaction constant increased by about 100% for the composite films containing MWCNTs at concentrations above 0.6 wt%. The key parameters for the enhancement of the photocatalytic performance are discussed. The presence of carbon nanotubes influences beneficially the degradation of 4-chlorophenol by an attack of the primarily photoproduced hydroxyl radicals onto the 4-chlorophenol molecules. The degradation due to the direct charge transfer is practically not influenced at all. PMID:27262272

  11. Some achievements of the Committee H "Soil Pollution, Degradation and Remediation"

    NASA Astrophysics Data System (ADS)

    Bech, J.

    2012-04-01

    The Soil System Sciences (SSS) Division, created by J. Weber in 2002 in the EGU, consists of 12 Committees, which cover significant topics of basic and applied Soil Science. One of them is the Committee H, dedicated to "Soil Pollution, Degradation and Remediation". This Committee had been active since 2004, and has organised 14 Sessions (i.e. SSS7, 2004, Nice, SSSS7, 2005, Vienna, SSS17, 2006, Vienna, etc. . . until SSS9.1, 2012, the present session). The title of the SSS7 Session (2004, Nice) was the same as the Committee "Soil pollution, degradation and remediation" and received 30 Contributions. The present Session SSS9.1 has received 40 Contributions. Since 2004 the 14 Sessions have included more than 400 Contributions (Oral and Poster) by applicants from more than 40 countries (european and extraeuropean). A good number of these contributions ("in extenso" papers) have been published in international journals. A selection of complete originals from these Sessions have been published in five Special Issues of the Journal of Geochemical Exploration, i.e.: Trace elements in Soils: baseline levels and imbalance (2008), Selenium and Iodine anomalies in Soils and health (2010), Pedogeochemical Mapping of Potentially Toxic Elements (2011), Reclamation of Mining Site Soils (2012) and "Phytoremediation of Polluted Soils" (in press). I conclude this overview our Committee H's work between 2003 and 2012 with a brief discussion of several examples. Finally, I would like to thank the founder of the SSS Division Prof. Dr. J. Weber for his outstanding work, as well as his successors Profs. T. Miano and A. Cerdà for continuing his excellent work.

  12. Development of MCM-41 based catalysts for the photo-Fenton's degradation of dye pollutants

    NASA Astrophysics Data System (ADS)

    Lam, Leung Yuk Frank

    The continuous advancement in most industries has resulted in serious water pollution problems. The industrial effluents contain a variety of highly toxic organics such as dye pollutants. Numerous processes have been demonstrated for treating such pollutants. Among them, photo-Fenton's reaction is effective for organic mineralization by hydroxyl radicals generated from the Fenton's reagents (Fe2+ and H2O2). However, there is a drawback in that it requires a separation system to recover the homogeneous ferrous ion in the treated wastewater. In this research, new heterogeneous Fenton's catalysts are developed to solve such a problem and to achieve an efficient mineralization of dye pollutants. Two methods for catalyst preparation, including sol-gel hydrothermal (SG) and metal-organic chemical vapor deposition (MOCVD) techniques, were studied in this work. For SG-prepared catalysts, the iron element was successfully doped into the MCM-41 structure. These catalysts demonstrated a good catalytic efficiency but leaching of metal ions from the developed catalyst was found. In the MOCVD technique, a rotated tubular reactor system was developed to synthesize Fe/MCM-41 catalyst with uniform metal dispersion. It was found that using oxygen as a carrier gas during metal deposition was able to increase the stability of the deposited metal. In degradation of a model dye pollutant, Orange II, a total of 85% TOC mineralization was achieved at pH 3. A disadvantage of using Fe/MCM-41 was the reduced efficiency at higher pH. Cu/MCM-41 was thus developed and showed better catalytic activities than Fe/MCM-41 at neutral pH. Having the specific catalytic properties of Fe/MCM-41 and Cu/MCM-41, bimetallic (Fe+Cu) catalysts supported on MCM-41 were developed which show better activities in the Orange II mineralization than those monometallic (Fe or Cu) catalysts. The preparation conditions of the catalysts were experimentally optimized. The effects of catalyst dosage, metal loading

  13. 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

  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. Variability of biological degradation of phenolic hydrocarbons in an aerobic aquifer determined by laboratory batch experiments

    NASA Astrophysics Data System (ADS)

    Nielsen, Per H.; Christensen, Thomas H.

    1994-11-01

    The biological aerobic degradation of 7 phenolic hydrocarbons (phenol, o-cresol, o-nitrophenol, p-nitrophenol, 2,6-dichlorophenol, 2,4-dichlorophenol, 4,6- o-dichlorocresol) and 1 aromatic hydrocarbon (nitrobenzene) was studied for 149 days in replicate laboratory batch microcosms with sediment and groundwater from 8 localities representing a 15 m × 30 m section of an aerobic aquifer. Three patterns of variation were found: (1) phenol, o-cresol and in most cases p-nitrophenol showed very fast degradation with no or only short lag phases and with very little variation among localities; (2) 2,4-dichlorophenol was degraded in all localities and showed large variability among localities with respect to lag phases (0-50 days) and some variation with respect to degradation periods (20-40 days); and (3) nitrobenzene, o-nitrophenol, 2,6-dichlorophenol and 4,6- o-dichlorocresol showed very large variability among localities ranging from no degradation within 149 days in some localities to degradation within 2 days in other localities. The degradation patterns were highly sequential, indicating a general sequence, for those compounds degradable, valid in all localities. The results are of importance in designing experimental determination of degradation rates and in assigning degradation parameters for use in solute transport models.

  17. 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.

  18. Potential particulate pollution derived from UV-induced degradation of odorous dimethyl sulfide.

    PubMed

    Qiao, Liping; Chen, Jianmin; Yang, Xin

    2011-01-01

    UV-induced degradation of odorous dimethyl sulfide (DMS) was carried out in a static White cell chamber with UV irradiation. The combination of in situ Fourier transform infrared (FT-IR) spectrometer, gas chromatograph-mass spectrometer (GC-MS), wide-range particle spectrometer (WPS) technique, filter sampling and ion chromatographic (IC) analysis was used to monitor the gaseous and potential particulate products. During 240 min of UV irradiation, the degradation efficiency of DMS attained 20.9%, and partially oxidized sulfur-containing gaseous products, such as sulfur dioxide (SO2), carbonyl sulfide (OCS), dimethyl sulfoxide (DMSO), dimethyl sulfone (DMSO2) and dimethyl disulfide (DMDS) were identified by in situ FT-IR and GC-MS analysis, respectively. Accompanying with the oxidation of DMS, suspended particles were directly detected to be formed by WPS techniques. These particles were measured mainly in the size range of accumulation mode, and increased their count median diameter throughout the whole removal process. IC analysis of the filter samples revealed that methanesulfonic acid (MSA), sulfuric acid (H2SO4) and other unidentified chemicals accounted for the major non-refractory compositions of these particles. Based on products analysis and possible intermediates formed, the degradation pathways of DMS were proposed as the combination of the O(1D)- and the OH- initiated oxidation mechanisms. A plausible formation mechanism of the suspended particles was also analyzed. It is concluded that UV-induced degradation of odorous DMS is potentially a source of particulate pollutants in the atmosphere. PMID:21476340

  19. 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

  20. 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

  1. 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

    2016-04-20

    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. PMID:27040040

  2. 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. PMID:26547568

  3. 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. PMID:22033355

  4. Enhanced catalytic oxidation ability of ternary layered double hydroxides for organic pollutants degradation.

    PubMed

    Fahel, Jean; Kim, Sanghoon; Durand, Pierrick; André, Erwan; Carteret, Cédric

    2016-05-10

    Co(2+) and Cu(2+) substituted MgAl layered double hydroxides with an M(2+)/M(3+) atomic ratio of 2.0 were synthesized by a co-precipitation method and fully characterized using various techniques including powder X-ray diffraction, ICP-AES analysis, FT-IR, DR UV-Vis spectroscopy, N2 adsorption-desorption and transmission electron microscopy. The materials revealed a good crystallinity with no phase impurity and successful substitution of cobalt and copper ions in the framework of binary LDH with the target ratio of metals in the sheet. The adsorption characteristics (kinetic and isotherm) and the catalytic oxidation of organic pollutants, methylene blue (cationic dye) and orange II (anionic) were carried out to investigate a potential use of LDH materials as catalysts. In particular, Co3Cu1Al2 LDH exhibited an excellent catalytic activity towards catalytic dye degradation, especially for orange II with good stability and reusability over several times. Furthermore, this LDH material showed good catalytic performance for several chlorophenol compounds, suggesting its practical application in wastewater treatment. Therefore, layered double hydroxides substituted with Co(2+) and Cu(2+) could be promising candidates in various applications, such as the abatement of organic pollutants. PMID:27097543

  5. 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. PMID:24981104

  6. Solar photo-ozonation: A novel treatment method for the degradation of water pollutants.

    PubMed

    Chávez, Ana M; Rey, Ana; Beltrán, Fernando J; Álvarez, Pedro M

    2016-11-01

    The decomposition of aqueous ozone by UV-vis radiation has been investigated with focus on the impact of ozone photolysis on the degradation of water pollutants during solar ozonation processes. The apparent first-order rate constants of the decomposition of ozone (kobs) have been determined at various pHs in the 4-9 range using radiation of different wavelengths in the UV-vis range. It was found that UVA-visible radiation (λ>320nm) highly enhanced ozone decomposition, especially at pH 4, for which kobs was three-folded with respect to the process in the absence of radiation. Hydrogen peroxide was identified as a main intermediate of ozone photo-decomposition at pH 4. Experiments of degradation of oxalic acid by ozone showed that solar irradiation brings about an increase in the hydroxyl radical to ozone exposures ratio (Rct). Finally, photo-ozonation (λ>300nm) was shown advantageous over single ozonation in the mineralization of a selection of emerging contaminants (metoprolol, ibuprofen, N,N-diethyl-meta-toluamide and clofibric acid) in both ultrapure water and a synthetic secondary effluent. Thus, TOC removal in 2-h treatments increased from 10 to 25% in the absence of radiation to about 50% in the presence of radiation. PMID:27258212

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

    PubMed

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

    2016-09-01

    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. PMID:27389817

  8. Biological effects of mercury pollution. (Latest citations from the NTIS bibliographic database). Published Search

    SciTech Connect

    1996-08-01

    The bibliography contains citations concerning biological and biochemical effects of mercury pollutants on humans, animals, and plants. References cover long-term and short-term experiments, biochemical reaction kinetics, pollution sources, and ecosystems. Mercury poisoning, metabolism, and related diseases are described. Carcinogenicity testing, health risk and assessment, and the effects on food chains are examined. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  9. 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.

  10. 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

  11. 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…

  12. Degradation of a mixture of pollutants in water using the UV/H2O2 process.

    PubMed

    Mariani, M L; Labas, M D; Brandi, R J; Cassano, A E; Zalazar, C S

    2010-01-01

    The degradation reaction of a simple mixture of pollutants (dichloroacetic acid + formic acid) employing H2O2 and UVC radiation (253.7 nm) has been studied in a well-mixed reactor which operates inside a recycling system. The aim of this work is to develop a systematic methodology for treating degradation of mixtures of pollutants, starting from a rather manageable system to more complex aggregates. In this contribution, the effects of different variables such as hydrogen peroxide/pollutant mixture initial concentration ratio, pH and incident radiation at the reactor wall were studied. The results show that the best degrading conditions are: pH = 3.5 and hydrogen peroxide concentrations from 3.9 to 11.8 mM (134-400 mg/L), for initial concentrations of 1.10 and 0.39 mM for formic acid and dichoroacetic acid respectively (50 mg/L for both pollutants). The influence of the incident radiation at the reactor wall on the degradation rates of the mixture is significant. In addition to this, it has been shown that in the employed aqueous solution no stable reaction intermediates are formed. On this basis, a complete reaction scheme for the mixture is proposed that is suitable for a reaction kinetics mathematical modeling of the mixture and further studies of increasing complexity. PMID:20555198

  13. 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. PMID:26125500

  14. 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. PMID:23791043

  15. 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.

  16. 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

  17. 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

    2014-10-01

    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. PMID:25294408

  18. 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. PMID:15884371

  19. Radiation induced degradation of polychlorinated biphenyls (PCBs) pollutants in paint scrapings.

    PubMed

    Singh, R K; Khandal, R K; Singh, Gurdeep

    2009-01-01

    Polychlorinated biphenyls (PCBs) are synthetic organic chemicals which have been commercially used worldwide in many specialty applications. In paints, PCBs were used because of their unique properties such as thermal stability, flame-resistance and low volatility. However, due to their adverse effects on human health and environment, the use of PCBs has now been banned. PCBs are today considered widespread pollutants in the global system . PCBs sources still exist in various products and in waste streams such as oil, paints, rubbers etc. Various remedial technologies have been developed in the world to detoxify PCBs. In the present study, radiolysis has been investigated as a safe means to reduce or destroy PCBs. Under this study, detoxification of PCBs in paint scrapings by gamma radiation using Cobalt 60 source has been investigated. The experimental results demonstrate that the gamma radiations can be an alternative environment- friendly technology for destroying PCBs. Gamma radiations also have the potential of being a preferred tool in comparison to the most widely used incineration method for destroying PCBs. The method used was found highly effective and destruction efficiency was as high as 91%. The degradation efficiency of PCBs was dependent on absorbed radiation dose, the type of PCBs and also on the source of paint scrapings. PMID:21114157

  20. Watering, fertilization, and slurry inoculation promote recovery of biological crust function in degraded soils.

    PubMed

    Maestre, Fernando T; Martín, Noelia; Díez, Beatriz; López-Poma, Rosario; Santos, Fernando; Luque, Ignacio; Cortina, Jordi

    2006-10-01

    Biological soil crusts are very sensitive to human-induced disturbances and are in a degraded state in many areas throughout their range. Given their importance in the functioning of arid and semiarid ecosystems, restoring these crusts may contribute to the recovery of ecosystem functionality in degraded areas. We conducted a factorial microcosm experiment to evaluate the effects of inoculation type (discrete fragments vs slurry), fertilization (control vs addition of composted sewage sludge), and watering frequency (two vs five times per week) on the cyanobacterial composition, nitrogen fixation, chlorophyll content, and net CO2 exchange rate of biological soil crusts inoculated on a semiarid degraded soil from SE Spain. Six months after the inoculation, the highest rates of nitrogen fixation and chlorophyll a content were found when the biological crusts were inoculated as slurry, composted sewage sludge was added, and the microcosms were watered five times per week. Net CO2 exchange rate increased when biological crusts were inoculated as slurry and the microcosms were watered five times per week. Denaturing gradient gel electrophoresis fingerprints and phylogenetic analyses indicated that most of the cyanobacterial species already present in the inoculated crust had the capability to spread and colonize the surface of the surrounding soil. These analyses showed that cyanobacterial communities were less diverse when the microcosms were watered five times per week, and that watering frequency (followed in importance by the addition of composted sewage sludge and inoculation type) was the treatment that most strongly influenced their composition. Our results suggest that the inoculation of biological soil crusts in the form of slurry combined with the addition of composted sewage sludge could be a suitable technique to accelerate the recovery of the composition and functioning of biological soil crusts in drylands. PMID:16710791

  1. Degradation of organic pollutants in wastewater by bicarbonate-activated hydrogen peroxide with a supported cobalt catalyst.

    PubMed

    Zhou, Li; Song, Wei; Chen, Zhuqi; Yin, Guochuan

    2013-04-16

    Developing novel technologies to cleanup wastewater has attracted attention for a long while in academic and industrial communities not only for environmental issues but also for recycling water sources. This work demonstrates that bicarbonate-activated H2O2 can be applied as a novel oxidant source in pollutant degradation. Using a supported cobalt catalyst, bicarbonate-activated H2O2 can efficiently degrade various dyes and phenol at ambient temperature. Because the reaction media remains weakly basic during degradation, the cobalt leaching from the solid catalyst has been efficiently avoided and the lifetime of the catalyst can be extended to above 180 h without significant activity loss in a fixed-bed test. Different scavengers, including ascorbic acid, t-butanol, sodium azide, benzoquinone, and tiron, have been tested to identify the active species, which may be involved in pollutant degradation, and it was found that singlet oxygen and the carbonate radical may play a key role in the degradation process. PMID:23495717

  2. In situ combined chemical and biological assessment of estrogenic pollution in a water recycling system.

    PubMed

    Chi, Yulang; Huang, Qiansheng; Zhang, Huanteng; Chen, Yajie; Dong, Sijun

    2016-05-01

    Estrogenic pollution and its control in aquatic systems have drawn substantial attention around the world. The chemical and biological assessment approaches currently utilized in the laboratory or field cannot give an integrated assessment of the pollution when used separately. In this study, in situ chemical and biological methods were combined to detect pollution in a water recycling system. Data for the water quality index (WQI) demonstrated that the water treatment resulted in the decline of pollution from upstream to downstream. Wild male Nile tilapia, Oreochromis niloticus, was sampled in June and September. The concentrations of four common endocrine disrupting chemicals (EDCs) were determined in the tilapia liver by chromatographic analysis methods. The level of 17β-estradiol (E2) declined from upstream to downstream in both months. In contrast, the levels of bisphenol A (BPA), di-(2-ethylhcxyl) phthalate (DEHP), and perfluorooctane sulfonate (PFOS) did not display this declining tendency. The highest relative expression of vitellogenin 1 (VTG1) was observed in tilapia from upstream, then the level significantly decreased along the water system. The relative expression levels of CYP1A1 in the water system were also significantly higher than that of the control. However, no declining trend could be observed along the water system. The change of VTG1 expression corresponded well with that of E2 levels in the tilapia liver. Overall, our study assessed the pollution by endocrine disruptors using chemical and biological data with good correspondence. This study also demonstrated the effectiveness of the water recycling system in eliminating estrogen pollution in municipal sewage. PMID:27155427

  3. Effects of air pollution on ecosystems and biological diversity in the eastern United States.

    PubMed

    Lovett, Gary M; Tear, Timothy H; Evers, David C; Findlay, Stuart E G; Cosby, B Jack; Dunscomb, Judy K; Driscoll, Charles T; Weathers, Kathleen C

    2009-04-01

    elevated exposure levels or in combination with other stresses such as drought, freezing, or pathogens. The notable exceptions are the acid/aluminum effects on aquatic organisms, which can be lethal at levels of acidity observed in many surface waters in the region. Although the effects are often subtle, they are important to biological conservation. Changes in species composition caused by terrestrial or aquatic acidification or eutrophication can propagate throughout the food webs to affect many organisms beyond those that are directly sensitive to the pollution. Likewise, sublethal doses of toxic pollutants may reduce the reproductive success of the affected organisms or make them more susceptible to potentially lethal pathogens. Many serious gaps in knowledge that warrant further research were identified. Among those gaps are the effects of acidification, ozone, and mercury on alpine systems, effects of nitrogen on species composition of forests, effects of mercury in terrestrial food webs, interactive effects of multiple pollutants, and interactions among air pollution and other environmental changes such as climate change and invasive species. These gaps in knowledge, coupled with the strong likelihood of impacts on ecosystems that have not been studied in the region, suggests that current knowledge underestimates the actual impact of air pollutants on biodiversity. Nonetheless, because known or likely impacts of air pollution on the biodiversity and function of natural ecosystems are widespread in the Northeast and Mid-Atlantic regions, the effects of air pollution should be considered in any long-term conservation strategy. It is recommended that ecologically relevant standards, such as "critical loads," be adopted for air pollutants and the importance of long-term monitoring of air pollution and its effects is emphasized. PMID:19432647

  4. Photoelectrocatalytic hydrogen generation and simultaneous degradation of organic pollutant via CdSe/TiO2 nanotube arrays

    NASA Astrophysics Data System (ADS)

    Wang, Wenchao; Li, Fang; Zhang, Dieqing; Leung, Dennis Y. C.; Li, Guisheng

    2016-01-01

    CdSe nanoparticles enhanced TiO2 nanotube arrays electrodes (CdSe/TNTAs) were explored as the photoanode for driving the photoelectrocatalytic (PEC) generation of hydrogen and simultaneous degradation of organic pollutants in a PEC system. The evolution hydrogen and the simultaneous degradation of organic pollutants were performed in an electrolytic cell (three electrodes system) under visible-light (λ > 400 nm). Such CdSe/TiO2 based PEC system exhibited both high efficiency of hydrogen generation and effective oxidation of methyl orange (MO). Such high PEC performance of CdSe/TNTAs was attributed to the high dispersity of CdSe nanoparticles on both outside and inside of the pore walls of TiO2 nanotube arrays, the strong combination and heterojunctions between CdSe and TiO2 through Cdsbnd O bonds via electrodeposition with ion-exchange method.

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

    PubMed Central

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

    2007-01-01

    Bioaugmentation of soil polluted with polycyclic aromatic hydrocarbons (PAHs) is often disappointing because of the low survival rate and low activity of the introduced degrader bacteria. We therefore investigated the possibility of priming PAH degradation in soil by adding 2% of bioremediated soil with a high capacity for PAH degradation. The culturable PAH-degrading community of the bioremediated primer soil was dominated by Mycobacterium spp. A microcosm containing pristine soil artificially polluted with PAHs and primed with bioremediated soil showed a fast, 100- to 1,000-fold increase in numbers of culturable phenanthrene-, pyrene-, and fluoranthene degraders and a 160-fold increase in copy numbers of the mycobacterial PAH dioxygenase gene pdo1. A nonpolluted microcosm primed with bioremediated soil showed a high rate of survival of the introduced degrader community during the 112 days of incubation. A nonprimed control microcosm containing pristine soil artificially polluted with PAHs showed only small increases in the numbers of culturable PAH degraders and no pdo1 genes. Initial PAH degradation rates were highest in the primed microcosm, but later, the degradation rates were comparable in primed and nonprimed soil. Thus, the proliferation and persistence of the introduced, soil-adapted degraders had only a marginal effect on PAH degradation. Given the small effect of priming with bioremediated soil and the likely presence of PAH degraders in almost all PAH-contaminated soils, it seems questionable to prime PAH-contaminated soil with bioremediated soil as a means of large-scale soil bioremediation. PMID:17209064

  6. 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. PMID:26331631

  7. 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. PMID:23065604

  8. 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. PMID:25875927

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. Mechanical degradation of biological heart valve tissue induced by low diameter crimping: an early assessment.

    PubMed

    Khoffi, Foued; Heim, Frederic

    2015-04-01

    Transcatheter aortic valve implantation (TAVI) has become today an increasingly attractive procedure to relieve patients from aortic valve disease. However, the procedure requires crimping biological tissue within a metallic stent for low diameter catheter insertion purpose. This step induces specific stress in the leaflets especially when the crimping diameter is small. One concern about crimping is the potential degradations undergone by the biological tissue, which may limit the durability of the valve once implanted. The purpose of the present work is to study the effect of low diameter crimping on the mechanical performances of pericardium valve prototypes. The prototypes were compressed to a diameter of 1mm within braided stents for 20 min. SEM observations performed on crimped material show that crimped leaflets undergo degradations characterized by apparent surface defects. Moreover mechanical extension tests were performed on pericardium strips before and after crimping. The strips (15 mm long, 5mm wide) were taken from both crimped and native leaflets considering 2 different valve diameters, 19 and 21 mm. In order to prevent the premature drying of the pericardium tissue during the procedure, the biological tissue was kept in contact with a formaldehyde solution. Results show that the ultimate strength value decreases nearly by up to 50%. The modifications observed in the material may jeopardize the long term durability of the device. However, further tests are necessary with a larger amount of samples to confirm these early results. PMID:25621851

  14. 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)

  15. Microbial Diversity of a Heavily Polluted Microbial Mat and Its Community Changes following Degradation of Petroleum Compounds

    PubMed Central

    Abed, Raeid M. M.; Safi, Nimer M. D.; Köster, Jürgen; de Beer, Dirk; El-Nahhal, Yasser; Rullkötter, Jürgen; Garcia-Pichel, Ferran

    2002-01-01

    We studied the microbial diversity of benthic cyanobacterial mats inhabiting a heavily polluted site in a coastal stream (Wadi Gaza) and monitored the microbial community response induced by exposure to and degradation of four model petroleum compounds in the laboratory. Phormidium- and Oscillatoria-like cyanobacterial morphotypes were dominant in the field. Bacteria belonging to different groups, mainly the Cytophaga-Flavobacterium-Bacteriodes group, the γ and β subclasses of the class Proteobacteria, and the green nonsulfur bacteria, were also detected. In slurry experiments, these communities efficiently degraded phenanthrene and dibenzothiophene completely in 7 days both in the light and in the dark. n-Octadecane and pristane were degraded to 25 and 34% of their original levels, respectively, within 7 days, but there was no further degradation until 40 days. Both cyanobacterial and bacterial communities exhibited noticeable changes concomitant with degradation of the compounds. The populations enriched by exposure to petroleum compounds included a cyanobacterium affiliated phylogenetically with Halomicronema. Bacteria enriched both in the light and in the dark, but not bacteria enriched in any of the controls, belonged to the newly described Holophaga-Geothrix-Acidobacterium phylum. In addition, another bacterial population, found to be a member of green nonsulfur bacteria, was detected only in the bacteria treated in the light. All or some of the populations may play a significant role in metabolizing the petroleum compounds. We concluded that the microbial mats from Wadi Gaza are rich in microorganisms with high biodegradative potential. PMID:11916684

  16. Microbial degradation of trichloroethylene in the rhizosphere: potential application to biological remediation of waste sites.

    PubMed Central

    Walton, B T; Anderson, T A

    1990-01-01

    The possibility that vegetation may be used to actively promote microbial restoration of chemically contaminated soils was tested by using rhizosphere and nonvegetated soils collected from a trichloroethylene (TCE)-contaminated field site. Biomass determinations, disappearance of TCE from the headspace of spiked soil slurries, and mineralization of [14C]TCE to 14CO2 all showed that microbial activity is greater in rhizosphere soils and that TCE degradation occurs faster in the rhizosphere than in the edaphosphere. Thus, vegetation may be an important variable in the biological restoration of surface and near-surface soils. PMID:2339867

  17. 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. PMID:26810667

  18. 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. PMID:26188871

  19. Association of allergic asthma emergency room visits with the main biological and chemical air pollutants.

    PubMed

    Makra, László; Matyasovszky, István; Bálint, Beatrix

    2012-08-15

    Joint effect of biological (pollen) and chemical air pollutants on asthma emergency room (ER) visits was analyzed for Szeged region of Southern Hungary. Our database of a nine-year period (1999-2007) includes daily number of asthma emergency room (ER) visits, and daily mean concentrations of CO, PM(10), NO, NO(2), O(3) and SO(2), furthermore two pollen variables (Ambrosia and total pollen excluding Ambrosia), as well. The analysis was performed for ER visits of asthma bronchiale using two age groups (adults and the elderly) of males and females for three seasons. Factor analysis was performed in order to clarify the relative importance of the pollutant variables affecting asthma ER visits. Asthma ER visits denote notably stronger associations with the pollutants in adult male than in adult female patients both for the pollen season of Ambrosia and the pollen-free season. Furthermore, adults are substantially more sensitive to severe asthma attack than the elderly for the season of total pollen excluding Ambrosia pollen. The joint effect of the chemical and pollen variables is the highest for the asthma ER cases in the pollen season of Ambrosia, basically due to the extra impact of the total pollen excluding Ambrosia pollen and partly due to Ambrosia pollen. A nonparametric regression technique was applied to discriminate between events of ER visit-no ER visit using pollen and chemical pollutants as explaining variables. Based on multiple correlations, the strongest relationships between ER visits and pollutants are observed during the pollen-free season. The elderly group with asthma bronchiale is characterized by weaker relationships between ER visits and pollutants compared to adults. Ratio of the number of correct decisions on the events of ER visit-no ER visit is lowest for the season of total pollen excluding Ambrosia pollen. Otherwise, similar conclusions hold as those received by multiple correlations. PMID:22750174

  20. Biological Assessment to Support Ecological Recovery of a Degraded Headwater System

    NASA Astrophysics Data System (ADS)

    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

  1. 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

  2. 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. PMID:27010848

  3. Gaseous pollutants emitted from a mechanical biological treatment plant for municipal solid waste: odor assessment and photochemical reactivity.

    PubMed

    Fang, Jingjing; Zhang, Hua; Yang, Na; Shao, Liming; He, Pinjing

    2013-11-01

    The concentrations and chromatographic profiles of gaseous pollutants emitted from a municipal solid waste (MSW) biological treatment plant were investigated to identify the major odor substances and atmospheric photochemical reactive species (PRS). Four methods were used to measure different gaseous pollutants in this study, including colorimetric tubes, gas chromatography with mass spectrometry/flame ionization detection/pulsed flame photometric detection (GC-MS/FID/PFPD) preceded by cold trap concentration, GC-FID preceded by solid-phase microextraction (SPME), and high-performance liquid chromatography (HPLC) after derivation by 2,4-dinitrophenylhydrazine (DNPH). Seventy-five gaseous compounds belonging to nine groups (nitrogen compounds, sulfur compounds, alkanes, alkenes, aromatics, terpenes, alcohols, carbonyls, and volatile fatty acids [VFAs]) were identified. In the pre-biotreatment facility, the total concentration of the gaseous pollutants reached the maximum value on day 7 (317 ppm). During the post-biotreatment process, the total concentration of gaseous pollutants decreased from 331 ppm at the beginning to 162 ppm in the end. The group with the greatest decrease was carbonyls, from 64 to 7.4 ppm, followed by alcohols, from 40 to 4.5 ppm, which were both oxygenated compounds. The proportion of aromatics was notably high in the pre-mechanical treatment facility, accounting for 50.6% of the total, revealing the xenobiotic compounds disseminated by stirring and agitating the waste in the initial stage. The proportions of nitrogen compounds were lower in the pre- and post-mechanical treatment facilities (1.5% and 6.9%) than in the pre- and post-biotreatment facilities (11.9% and 13:8%), suggesting that their generation was closely associated with waste degradation. The major odor compounds in the facilities were acetic acid, butyric acid, valeric acid, isovaleric acid, and dimethyl sulfide. The major PRS in the facilities were aromatics, acetaldehyde

  4. 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. PMID:26994335

  5. 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. PMID:20821580

  6. {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.

  7. Degradation of a model pollutant ferulic acid by the endophytic fungus Phomopsis liquidambari.

    PubMed

    Xie, Xing-Guang; Dai, Chuan-Chao

    2015-03-01

    Biodegradation of ferulic acid, by an endophytic fungus called Phomopsis liquidambari was investigated in this study. This strain can use ferulic acid as the sole carbon for growth. Both in mineral salt medium and in soil, more than 97% of added ferulic acid was degraded within 48 h. The metabolites were identified and quantified using GC-MS and HPLC-MS. Ferulic acid was first decarboxylated to 4-vinyl guaiacol and then oxidized to vanillin and vanillic acid, followed by demethylation to protocatechuic acid, which was further degraded through the β-ketoadipate pathway. During degradation, ferulic acid decarboxylase, laccase and protocatechuate 3,4-dioxygenase activities and their gene transcription levels were significantly affected by the variation of substrate and product concentrations. Moreover, ferulic acid degradation was determined to some extent by P. liquidambari laccase. This study is the first report of an endophytic fungus that has a great potential for practical application in ferulic acid-contaminated environments. PMID:25514400

  8. Adverse effects of air pollutants on wood products and a method for preventing resulting degradation

    SciTech Connect

    Chao, W.Y.

    1992-01-01

    A study of wood surface in hostile environments was undertaken to elucidate the degradation mechanism and develop a method to protect wood in outdoor applications. In this investigation, wood was exposed to SO[sub 2] and NO[sub 2] in the presence and absence of ultraviolet light for up to 4 weeks. The effect of the simulated acid rain on wood with and without an epoxy film was evaluated by intermittent spraying of the wood with either sulfuric, nitric acid or water and irradiated with and without the xenon light in a weatherometer for up to 8 weeks. The surface properties of degraded wood and protective epoxy films were analyzed. UV light changed the wood color. The samples lost weight and generated water-soluble degradation products after the photoirradiation. Sulfur dioxide lighted the wood color; nitrogen dioxide changed wood color to brown. Wood increased its weight during the exposure of SO[sub 2] and NO[sub 2], however, the presence of such gases triggered photo-induced degradation. Lignin was degraded and carbonyl groups were formed at irradiated wood. Sulfur and nitrogen dioxides reduced the intensity of carbonyl groups due to degradative hydrolysis. Water-soluble products were derived from polysaccharides and lignin, nitric acid, sulfuric acid and its dissociated ions. During the simulated acidic weathering, xenon light changed the wood color. The color change rate of earlywood was greater than latewood. The presence of acids and water facilitated the wood degradation, and eventually caused leaching. The primary photodegradation phenomena of lignin was confirmed by the FTIR and UV analyses of the irradiated samples. Transparent anhydride-cured epoxy films partially protected wood against the acidic degradation and photoirradiation. Epoxy film cracked, yellowed and had O-ring shapes cavities after the exposure. Salol-added film provided the best protection for wood, followed by a film without an UV stabilizer and Tinuvin 770-added film last.

  9. 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.

  10. The economics of environmental degradation from pollution-intensive multinational enterprises in less developed countries

    SciTech Connect

    Grivoyannis, E.C.

    1997-06-01

    The economic productivity of ecological systems constitutes imperfectly known resources for many developing countries and, as a result, national incentives for their preservation are hampered. Scarcity of capital and foreign exchange, on the other hand, creates for these countries an economic pressure to reduce environmental quality standards in return for foreign exchange from pollution-intensive multinational enterprises. For a bargaining outcome to be considered successful, the host country`s marginal cost of environmental protection should be equal to the social scarcity cost of foreign exchange for capital accumulation. However, imperfections in the international capital markets and in he information processing of private and government institutions as well as government failure may upgrade the value of foreign exchange relative to environmental protection. As a result, many developing countries may prefer to have more direct investment gains derived from an inflow of foreign exchange by allowing pollution-intensive multinationals an excessive amount of pollution, than the strategically optimal one, if these enterprises are prepared to shift operations to their country. Strategic bargaining by pollution-intensive multinationals can turn the economic pressures of developing countries into an exploitable dependence. This paper investigates the socio-economic outcome from strategic bargaining opportunities between developing countries and pollution-intensive multinationals in an effort to provide a better understanding of what is negotiable in the presence of exploitable dependencies.

  11. 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. PMID:23162813

  12. Evaluating the biological activity of oil-polluted soils using a complex index

    NASA Astrophysics Data System (ADS)

    Kabirov, R. R.; Kireeva, N. A.; Kabirov, T. R.; Dubovik, I. Ye.; Yakupova, A. B.; Safiullina, L. M.

    2012-02-01

    A complex index characterizing the biological activity of soils (BAS) is suggested. It is based on an estimate of the level of activity of catalase; the number of heterotrophic and hydrocarbon oxidizing microorganisms, microscopic fungi, algae, and cyanobacteria; and the degree of development of higher plants and insects in the studied soil. The data on using the BAS coefficient for evaluating the efficiency of rehabilitation measures for oil-polluted soils are given. Such measures included introducing the following biological preparations: Lenoil based on a natural consortium of microorganisms Bacillus brevis and Arthrobacter sp.; the Azolen biofertilizer with complex action based on Azotobacter vinelandii; the Belvitamil biopreparation, which is the active silt of pulp and paper production; and a ready-mixed industrial association of aerobic and anaerobic microorganisms that contains hydrocarbon oxidizing microorganisms of the Arthrobacter, Bacillus, Candida, Desulfovibrio, and Pseudomonas genera.

  13. 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. PMID:18472555

  14. 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. PMID:21862133

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

    PubMed

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

    2016-11-15

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

  16. Evaluation of Biological and Physical Protection against Nuclease Degradation of Clay-Bound Plasmid DNA

    PubMed Central

    Demanèche, Sandrine; Jocteur-Monrozier, Lucile; Quiquampoix, Hervé; Simonet, Pascal

    2001-01-01

    In order to determine the mechanisms involved in the persistence of extracellular DNA in soils and to monitor whether bacterial transformation could occur in such an environment, we developed artificial models composed of plasmid DNA adsorbed on clay particles. We determined that clay-bound DNA submitted to an increasing range of nuclease concentrations was physically protected. The protection mechanism was mainly related to the adsorption of the nuclease on the clay mineral. The biological potential of the resulting DNA was monitored by transforming the naturally competent proteobacterium Acinetobacter sp. strain BD413, allowing us to demonstrate that adsorbed DNA was only partially available for transformation. This part of the clay-bound DNA which was available for bacteria, was also accessible to nucleases, while the remaining fraction escaped both transformation and degradation. Finally, transformation efficiency was related to the perpetuation mechanism, with homologous recombination being less sensitive to nucleases than autonomous replication, which requires intact molecules. PMID:11133458

  17. 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.

  18. Microwave-assisted chemical oxidation of biological waste sludge: simultaneous micropollutant degradation and sludge solubilization.

    PubMed

    Bilgin Oncu, Nalan; Akmehmet Balcioglu, Isil

    2013-10-01

    Microwave-assisted hydrogen peroxide (MW/H2O2) treatment and microwave-assisted persulfate (MW/S2O8(2-)) treatment of biological waste sludge were compared in terms of simultaneous antibiotic degradation and sludge solubilization. A 2(3) full factorial design was utilized to evaluate the influences of temperature, oxidant dose, and holding time on the efficiency of these processes. Although both MW/H2O2 and MW/S2O8(2-) yielded ≥97% antibiotic degradation with 1.2g H2O2 and 0.87 g S2O8(2-) per gram total solids, respectively, at 160 °C in 15 min, MW/S2O8(2-) was found to be more promising for efficient sludge treatment at a lower temperature and a lower oxidant dosage, as it allows more effective activation of persulfate to produce the SO4(-) radical. Relative to MW/H2O2, MW/S2O8(2-) gives 48% more overall metal solubilization, twofold higher improvement in dewaterability, and the oxidation of solubilized ammonia to nitrate in a shorter treatment period. PMID:23928124

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

    PubMed Central

    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.

    2011-01-01

    Southeast Asia is a hotspot of imperilled 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 imperilled 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. PMID:20685713

  20. 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. PMID:25724976

  1. 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. PMID:24373130

  2. 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

  3. 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,...

  4. 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. PMID:27184147

  5. 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.

  6. Mixed Pollutant Degradation by Methylosinus trichosporium OB3b Expressing either Soluble or Particulate Methane Monooxygenase: Can the Tortoise Beat the Hare?▿

    PubMed Central

    Lee, Sung-Woo; Keeney, David R.; Lim, Dong-Hee; Dispirito, Alan A.; Semrau, Jeremy D.

    2006-01-01

    Methanotrophs have been widely investigated for in situ bioremediation due to their ubiquity and their ability to degrade halogenated hydrocarbons through the activity of methane monooxygenase (MMO). It has been speculated that cells expressing the soluble form of MMO (sMMO) are more efficient in cleaning up sites polluted with halogenated hydrocarbons due to its broader substrate range and relatively fast degradation rates compared cells expressing the other form of MMO, the particulate MMO (pMMO). To examine this issue, the biodegradation of mixtures of chlorinated solvents, i.e., trichloroethylene (TCE), trans-dichloroethylene (t-DCE), and vinyl chloride (VC), by Methylosinus trichosporium OB3b in the presence of methane using either form of MMO was investigated over longer time frames than those commonly used, i.e., days instead of hours. Growth of M. trichosporium OB3b along with pollutant degradation were monitored and analyzed using a simple comparative model developed from the Ω model created for analysis of the competitive binding of oxygen and carbon dioxide by ribulose bisphosphate carboxylase. From these findings, it appears that at concentrations of VC, t-DCE, and TCE greater than 10 μM each, methanotrophs expressing pMMO have a competitive advantage over cells expressing sMMO due to higher growth rates. Despite such an apparent growth advantage, pMMO-expressing cells degraded less of these substrates at these concentrations than sMMO-expressing cells during active growth. If the concentrations were increased to 100 μM, however, not only did pMMO-expressing cells grow faster, they degraded more of these pollutants and did so in a shorter amount of time. These findings suggest that the relative rates of growth substrate and pollutant degradation are important factors in determining which form of MMO should be considered for pollutant degradation. PMID:17012599

  7. 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. PMID:26501718

  8. 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.

  9. Primary and complex stressors in polluted mediterranean rivers: Pesticide effects on biological communities

    NASA Astrophysics Data System (ADS)

    Ricart, Marta; Guasch, Helena; Barceló, Damià; Brix, Rikke; Conceição, Maria H.; Geiszinger, Anita; José López de Alda, Maria; López-Doval, Julio C.; Muñoz, Isabel; Postigo, Cristina; Romaní, Anna M.; Villagrasa, Marta; Sabater, Sergi

    2010-03-01

    SummaryWe examined the presence of pesticides in the Llobregat river basin (Barcelona, Spain) and their effects on benthic biological communities (invertebrates and diatoms). The Llobregat river is one of Barcelona's major drinking water resources. It has been highly polluted by industrial, agricultural, and urban wastewaters, and—as a typical Mediterranean river—is regularly subjected to periodic floods and droughts. Water scarcity periods result in reduced water flow and dilution capacity, increasing the potential environmental risk of pollutants. Seven sites were selected, where we analysed the occurrence of 22 pesticides (belonging to the classes of triazines, organophosphates, phenylureas, anilides, chloroacetanilides, acidic herbicides and thiocarbamates) in the water and sediment, and the benthic community structure. Biofilm samples were taken to measure several metrics related to both the algal and bacterial components of fluvial biofilms. Multivariate analyses revealed a potential relationship between triazine-type herbicides and the distribution of the diatom community, although no evidence of disruption in the invertebrate community distribution was found. Biofilm metrics were used as response variables rather than abundances of individual species to identify possible cause-effect relationships between pesticide pollution and biotic responses. Certain effects of organophosphates and phenylureas in both structural and functional aspects of the biofilm community were suggested, but the sensitivity of each metric to particular stressors must be assessed before we can confidently assign causality. Complemented with laboratory experiments, which are needed to confirm causality, this approach could be successfully incorporated into environmental risk assessments to better summarise biotic integrity and improve the ecological management.

  10. Biological monitoring and allergic sensitization in traffic police officers exposed to urban air pollution.

    PubMed

    Vimercati, L; Carrus, A; Bisceglia, L; Tatò, I; Bellotta, M R; Russo, A; Martina, G; Daprile, C; Di Leo, E; Nettis, E; Assennato, G

    2006-01-01

    Urban air pollution is associated with an increased incidence of allergic respiratory diseases. The aim of this study is to assess the occupational exposure to urban pollution through biological monitoring of PAHs and CO airborne levels in 122 traffic wardens in Bari, Italy and to investigate sensitization to inhaled allergens in a subgroup of workers. After filling in a questionnaire on lifestyle habits and occupational history, a medical examination, spirometry were carried out and blood samples were taken; the measurement of exhaled CO and urinary 1-hydroxypyrene (1-HOP) was performed and data on the air quality of Bari Municipality were obtained. Specific IgE dosage and skin prick tests were done on 18 workers giving altered values of spirometry or anamnestic allergic symptoms. Urinary 1-HOP showed median levels of 0.1 microMol/Mol(creat) (range 0.02-6.68) and was not influenced by smoking habits, work tasks, area of the city and environmental levels of PM10. Exhaled CO, with median value of 1 ppm (range 0-27), was significantly higher in smokers than in non-smokers, while no other variable seemed to play a role in modifying the levels. Specific IgE production versus inhalant allergens was found in 6 cases. Positive skin prick test results were observed in 11 cases. Allergic rhinitis was diagnosed in 6 cases. At least one of the allergometric tests performed was positive in 61 percent of the subjects. In conclusion, our results suggest the importance of introducing allergic status evaluation in this class of workers, exposed to several urban air pollutants. PMID:17291408

  11. Recommendations on methods for the detection and control of biological pollution in marine coastal waters.

    PubMed

    Olenin, Sergej; Elliott, Michael; Bysveen, Ingrid; Culverhouse, Phil F; Daunys, Darius; Dubelaar, George B J; Gollasch, Stephan; Goulletquer, Philippe; Jelmert, Anders; Kantor, Yuri; Mézeth, Kjersti Bringsvor; Minchin, Dan; Occhipinti-Ambrogi, Anna; Olenina, Irina; Vandekerkhove, Jochen

    2011-12-01

    Adverse effects of invasive alien species (IAS), or biological pollution, is an increasing problem in marine coastal waters, which remains high on the environmental management agenda. All maritime countries need to assess the size of this problem and consider effective mechanisms to prevent introductions, and if necessary and where possible to monitor, contain, control or eradicate the introduced impacting organisms. Despite this, and in contrast to more enclosed water bodies, the openness of marine systems indicates that once species are in an area then eradication is usually impossible. Most institutions in countries are aware of the problem and have sufficient governance in place for management. However, there is still a general lack of commitment and concerted action plans are needed to address this problem. This paper provides recommendations resulting from an international workshop based upon a large amount of experience relating to the assessment and control of biopollution. PMID:21889171

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

    PubMed Central

    Pfahler, P L

    1981-01-01

    In vitro pollen germination was examined as a method to determine the mutagenic and physiological effects of environmental pollutants on higher organisms. Results were presented indicating that mutations could be distinguished by their in vitro germination characteristics if sporophytes homozygous for the mutated allele were tested. The addition of agents directly into the in vitro medium was shown to be an effective method to assess their physiological effects. The exposure of pollen grains during the in vitro germination process to ultraviolet radiation in the B range (280-320 nm) was found to produce little or no change in the germination or ruptured percentage but a sharp decrease in pollen tube growth after 1 hr. In vitro pollen germination appears to be a valuable method to examine the mutation types and physiological effects produced by a broad range of environmental pollutants. In fact, since in vitro germination is related to reproduction and gene transmission, the biological activity of these agents on in vitro germination should be tested routinely to determine their possible effects on food production and gene frequency changes in future generations. Images FIGURE 1. FIGURE 3. PMID:7460877

  13. 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. PMID:25563204

  14. 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

  15. 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. PMID:23863375

  16. A biological quality index for volcanic Andisols and Aridisols (Canary Islands, Spain): variations related to the ecosystem degradation.

    PubMed

    Armas, Cecilia María; Santana, Bayanor; Mora, Juan Luis; Notario, Jesús Santiago; Arbelo, Carmen Dolores; Rodríguez-Rodríguez, Antonio

    2007-05-25

    The aim of this work is to identify indicators of biological activity in soils from the Canary Islands, by studying the variation of selected biological parameters related to the processes of deforestation and accelerated soil degradation affecting the Canarian natural ecosystems. Ten plots with different degrees of maturity/degradation have been selected in three typical habitats in the Canary Islands: laurel forest, pine forest and xerophytic scrub with Andisols and Aridisols as the most common soils. The studied characteristics in each case include total organic carbon, field soil respiration, mineralized carbon after laboratory incubation, microbial biomass carbon, hot water-extractable carbon and carboxymethylcellulase, beta-d-glucosidase and dehydrogenase activities. A Biological Quality Index (BQI) has been designed on the basis of a regression model using these variables, assuming that the total soil organic carbon content is quite stable in nearly mature ecosystems. Total carbon in mature ecosystems has been related to significant biological variables (hot water-extractable carbon, soil respiration and carboxymethylcellulase, beta-d-glucosidase and dehydrogenase activities), accounting for nearly 100% of the total variance by a multiple regression analysis. The index has been calculated as the ratio of the value calculated from the regression model and the actual measured value. The obtained results show that soils in nearly mature ecosystems have BQI values close to unit, whereas those in degraded ecosystems range between 0.24 and 0.97, depending on the degradation degree. PMID:17316768

  17. 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...

  18. 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...

  19. 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.

  20. 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

  1. 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.

  2. 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. PMID:24779765

  3. Facile synthesis of ZnO/CuInS2 nanorod arrays for photocatalytic pollutants degradation.

    PubMed

    Yang, Yawei; Que, Wenxiu; Zhang, Xinyu; Xing, Yonglei; Yin, Xingtian; Du, Yaping

    2016-11-01

    Vertically-aligned ZnO nanorod arrays on a fluorine-doped tin oxide glass substrate were homogeneously coated with visible light active CuInS2 quantum dots by using a controllable electrophoretic deposition strategy. Compared with the pure ZnO nanorod arrays, the formation of high-quality ZnO/CuInS2 heterojunction with well-matched band energy alignment expanded the light absorption from ultraviolet to visible region and facilitated efficient charge separation and transportation, thus yielding remarkable enhanced photoelectrochemical performance and photocatalytic activities for methyl orange and 4-chlorophenol degradation. The ZnO/CuInS2 film with the deposition duration of 80min showed the highest degradation rate and photocurrent density (0.95mA/cm(2)), which was almost 6.33 times higher than that of the pure ZnO nanorod arrays film. The CuInS2 QDs sensitized ZnO nanorod arrays film was proved to be a superior structure for photoelectrochemical and photocatalytic applications due to the optimized CuInS2 loading and well-maintained one-dimensional nanostructure. PMID:27322900

  4. Alkali metal ion induced cube shaped mesoporous hematite particles for improved magnetic properties and efficient degradation of water pollutants.

    PubMed

    Roy, Mouni; Naskar, Milan Kanti

    2016-07-27

    Mesoporous cube shaped hematite (α-Fe2O3) particles were prepared using FeCl3 as an Fe(3+) precursor and 1-butyl-3-methylimidazolium bromide (ionic liquid) as a soft template in the presence of different alkali metal (lithium, sodium and potassium) acetates, under hydrothermal conditions at 150 °C/4 h followed by calcination at 350 °C. The formation of the α-Fe2O3 phase in the synthesized samples was confirmed by XRD, FTIR and Raman spectroscopy. Unlike K(+) ions, intercalation of Li(+) and Na(+) ions occurred in α-Fe2O3 crystal layers as evidenced by XRD and Raman spectroscopy. Electron microscopy (FESEM and TEM) images showed the formation of cube-like particles of different sizes in the presence of Li(+), Na(+) and K(+) ions. The mesoporosity of the products was confirmed by N2 adsorption-desorption studies, while their optical properties were analyzed by UV-DRS. Na(+) ion intercalated α-Fe2O3 microcubes showed improved coercivity (5.7 kOe) due to increased strain in crystals, and shape and magnetocrystalline anisotropy. Temperature dependent magnetization of the samples confirmed the existence of Morin temperature in the range of 199-260 K. Catalytic degradation of methylene blue (MB), a toxic water pollutant, was studied using the synthesized products via a heterogeneous photo-Fenton process. The degradation products were traced by electrospray ionization-mass spectrometry (ESI-MS). The α-Fe2O3 microcubes obtained in the presence of Na(+) ions exhibited a more efficient degradation of MB to non-toxic open chain products. PMID:27406648

  5. Degradation of atrazine by microbial consortium in an anaerobic submerged biological filter.

    PubMed

    Nasseri, Simin; Baghapour, Mohammad Ali; Derakhshan, Zahra; Faramarzian, Mohammad

    2014-09-01

    Atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) (ATZ) is one of the components of S-triazine. Due to its certain characteristics, ATZ causes pollution in various ecosystems and has been of concern for its probable carcinogenic effects on humans. Researchers have used chemical and physical methods for removing ATZ from the environment. Although these methods are quick, they have not been capable of complete mineralization. Therefore, researchers are looking for methods with lower energy consumption and cost and higher efficiency. In this study, biodegradation of ATZ by microbial consortium was evaluated in the aquatic environment. The present study aimed to evaluate the efficiency of ATZ removal from aqueous environments by using an anaerobic submerged biological filter in four concentration levels of atrazine and three hydraulic retention times. The maximum efficiencies of ATZ and soluble chemical oxygen demand (SCOD) were 51.1 and 45.6%, respectively. There was no accumulation of ATZ in the biofilm and the loss of ATZ in the control reactor was negligible. This shows that ATZ removal in this system was due to biodegradation. Furthermore, the results of modeling showed that the Stover-Kincannon model had desirable fitness (R² > 99%) in loading ATZ in this biofilter. PMID:25252353

  6. 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. PMID:26953729

  7. 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. PMID:25203235

  8. 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.

  9. 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. PMID:25289459

  10. Dark ambient degradation of Bisphenol A and Acid Orange 8 as organic pollutants by perovskite SrFeO₃-δ metal oxide.

    PubMed

    Leiw, Ming Yian; Guai, Guan Hong; Wang, Xiaoping; Tse, Man Siu; Ng, Chee Mang; Tan, Ooi Kiang

    2013-09-15

    Current advanced oxidation processes (AOPs) are chemically and energetically intensive processes, which are undesirable for cost-effective and large-scale system water treatment and wastewater recycling. This study explored the Strontium Ferrite (SFO) metal oxide on the degradation of highly concentrated organic pollutants under dark ambient condition without any external stimulants. The SFO particles with single perovskite structure were successfully synthesized with a combined high temperature and high-energy ball milling process. An endocrine disruptor, Bisphenol A (BPA) and an azo dye, Acid Orange 8 (AO8) were used as probe organic pollutants. BPA was completely degraded with 83% of mineralization in 24 h while rapid decoloration of AO8 was achieved in 60 min and complete breakdown into primary intermediates and aliphatic acids occurred in 24 h under the treatment of dispersed SFO metal oxide in water. Such efficient degradation could be attributed to the enhanced adsorption of these anionic pollutants on positively charged ball-milled SFO metal oxide surface, resulted in higher degradation activity. Preliminary degradation mechanisms of BPA and AO8 under the action of SFO metal oxide were proposed. These results showed that the SFO metal oxide could be an efficient alternative material as novel advanced oxidation technology for low cost water treatment. PMID:23742952

  11. 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. PMID:24582425

  12. Cation exchange resin immobilized bimetallic nickel-iron nanoparticles to facilitate their application in pollutants degradation.

    PubMed

    Ni, Shou-Qing; Yang, Ning

    2014-04-15

    Nanoscale zerovalent iron (nZVI) usually suffers from reduction of reactivity by aggregation, difficulty of assembling, environmental release and health concerns. Furthermore, data are lacking on the effect of cheap nickel on debromination of decabromodiphenyl ether (DBDE) by immobilized nZVI in aqueous system. In this study, strong acid polystyrene cation-exchange resins with particle diameter from 0.4 to 0.6 mm were utilized as matrices to immobilize bimetallic nickel-iron nanoparticles in order to minimize aggregation and environmental leakage risks of nZVI and to enhance their reactivity. Elemental distribution mapping showed that iron particles distributed uniformly on the surface of the resin and nickel particles were dispersed homogeneously into Fe phase. The reaction rate of resin-bound nZVI is about 55% higher than that of dispersed nZVI. The immobilized bimetallic nanoparticles with 9.69% Ni had the highest debromination percent (96%) and reaction rate (0.493 1/h). The existence of Ni significantly improved the debromination rate, due to the surface coverage of catalytic metal on the reductive metal and the formation of a galvanic cell. The environmental dominant congeners, such as BDE 154, 153, 100, 99 and 47, were produced during the process. Outstanding reactive performance, along with magnetic separation assured that resin-bound bimetallic nickel-iron nanoparticles are promising material that can be utilized to remediate a wide variety of pollutants contaminated sites including polybrominated diphenyl ethers. PMID:24559714

  13. 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. PMID:24433792

  14. Isolation, fingerprinting and genetic identification of indigenous PAHs degrading bacteria from oil-polluted soils.

    PubMed

    Alrumman, Sulaiman A; Hesham, Abd El-Latif; Alamri, Saad A

    2016-01-01

    In the present study, thirty five bacterial isolates were obtained from hydrocarbon-contaminated soil samples using an enrichment method. These isolates were tested to grow on mineral salt medium containing anthracene or phenanthrene as sole carbon source. Only five isolates showed the ability to degrade these compounds. RAPD-PCR fingerprinting was carried out for the five isolates, and the DNA patterns revealed that there was no similarity among the examined bacteria whenever the RFLP using four restriction enzymes HaeIII, Msp1, Hinf1 and Taq1 failed to differentiate among them. Five bacterial isolates were grown in high concentration of anthracene and phenanthrene (4% w/v). Two bacterial isolates were selected due to their high ability to grow in the presence of high concentrations of anthracene and phenanthrene. The isolates were identified as Bacillus flexus and Ochrobactrum anthropi, based on DNA sequencing of amplified 16S rRNA gene and phylogenetic analysis. Finally, the ability of these bacterial strains to tolerate and remove different PAHs looked promising for application in bioremediation technologies. PMID:26930863

  15. Degradation of water polluted with used cooking oil by solar photolysis, Fenton and solar photo Fenton.

    PubMed

    Vergara-Sánchez, J; Silva-Martínez, S

    2010-01-01

    The degradation of used cooking safflower oil aqueous solutions by photolysis, Fenton, and photo Fenton under solar light is reported. The processes were carried out in a photochemical reactor with recirculation. Operating variables such as, pH, oil concentration and molar ratio of [H(2)O(2)]:[oil] were investigated to test their effects on the treatment efficiency of Fenton process. Also the iron catalyzed decomposition of hydrogen peroxide in the solar photo Fenton reaction was studied under different experimental conditions. The degree of oil oxidation was monitored by the measurements of chemical oxygen demand (COD) analyses. It was found that at pH 2.6 and a molar ratio of [H(2)O(2)]:[oil] of 489:1 were more efficient for COD abatement. The experimental results showed that the sole effect of the solar irradiation (photolysis) aided to decrease approximately 65% of COD at neutral pH in a reaction time period of 15 h; whereas a decrease of 47% and approximately 90% of COD was obtained by Fenton and photo Fenton treatment, respectively, after a reaction time of 50 min. It was observed a decrease in the decomposition of H(2)O(2) in the solar photo Fenton process, in subsequent additions of H(2)O(2), and H(2)O(2) + Fe(2+). PMID:20595756

  16. Structure and photocatalysis activity of silver doped titanium oxide nanotubes array for degradation of pollutants

    NASA Astrophysics Data System (ADS)

    Al-Arfaj, E. A.

    2013-10-01

    Semiconductor titanium oxide showed a wonderful performance as a photocatalysis for environmental remediation. Owing to high stability and promising physicochemical properties, titanium oxide nanostructures are used in various applications such as wastewater treatment, antimicrobial and air purification. In the present study, titanium oxide nanotubes and silver doped titanium oxide nanotubes were synthesized via anodic oxidation method. The morphology and composition structure were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results depicted that nanotubes possess anatase phase with average tube diameter of 65 nm and 230 ± 12 nm in length. The band gap of the un-doped and silver doped titanium dioxide nanotubes was determined using UV-Vis. spectrophotometer. The results showed that the band gap of titanium dioxide nanotubes is decreased when doped with silver ions. The photocatalysis activity of un-doped and silver doped TiO2 nanotubes were evaluated in terms of degradation of phenol in the presence of ultra violet irradiation. It was found that silver doped TiO2 nanotubes exhibited much higher photocatalysis activity than un-doped TiO2 nanotubes.

  17. 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.

  18. Comparison of differential gene expression to water stress among bacteria with relevant pollutant-degradation properties.

    PubMed

    Moreno-Forero, Silvia K; Rojas, Edward; Beggah, Siham; van der Meer, Jan R

    2016-02-01

    Resistance to semi-dry environments has been considered a crucial trait for superior growth and survival of strains used for bioaugmentation in contaminated soils. In order to compare water stress programmes, we analyse differential gene expression among three phylogenetically different strains capable of aromatic compound degradation: Arthrobacter chlorophenolicus A6, Sphingomonas wittichii RW1 and Pseudomonas veronii  1YdBTEX2. Standardized laboratory-induced water stress was imposed by shock exposure of liquid cultures to water potential decrease, induced either by addition of solutes (NaCl, solute stress) or by addition of polyethylene glycol (matric stress), both at absolute similar stress magnitudes and at those causing approximately similar decrease of growth rates. Genome-wide differential gene expression was recorded by micro-array hybridizations. Growth of P. veronii 1YdBTEX2 was the most sensitive to water potential decrease, followed by S. wittichii RW1 and A. chlorophenolicus A6. The number of genes differentially expressed under decreasing water potential was lowest for A. chlorophenolicus A6, increasing with increasing magnitude of the stress, followed by S. wittichii RW1 and P. veronii 1YdBTEX2. Gene inspection and gene ontology analysis under stress conditions causing similar growth rate reduction indicated that common reactions among the three strains included diminished expression of flagellar motility and increased expression of compatible solutes (which were strain-specific). Furthermore, a set of common genes with ill-defined function was found between all strains, including ABC transporters and aldehyde dehydrogenases, which may constitute a core conserved response to water stress. The data further suggest that stronger reduction of growth rate of P. veronii 1YdBTEX2 under water stress may be an indirect result of the response demanding heavy NADPH investment, rather than the presence or absence of a suitable stress defence

  19. 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.

  20. [Bio-security with emphasis in biological polluting agents in health workers].

    PubMed

    Ardila, Ana Maria; Muñoz, Alba Idaly

    2009-01-01

    Health workers of the emergency service are frequently exposed to different dangers, among them the contact with biological polluting agents. This is a study of descriptive character, with the objective to characterize workers on social demographic aspects, and also to verify the level of application of the bio-security norms at the emergency services of a health institution in the city of Bogota, Colombia. 68,3% of the workers are with a contract in the modality of benefit of services, the 31,7%, are in the modality of indefinite term. 44,6% of the personnel have not received the qualification on bio-security, and 42,4% do not apply the suitable technique of washing hands. In relation to the aspect of the return to use needles, 31% was doing this practice. All workers have the complete kit of Hepatitis B vaccine, but the same percentage does not have measurement of Hepatitis B antibodies. It is fundamental the provision of elements of personal protection and set of elements and containers that contribute to the bio-security. Pedagogical activities can be used to sensitize and create critical awareness to all personnel who work at emergency, about dangers and consequences that are exposed in their workplace. Measurements of titles of Hepatitis B are necessary to verify the immunological state of the workers. PMID:20069181

  1. Potential Technology for Studying Dosimetry and Response to Airborne Chemical and Biological Pollutants

    SciTech Connect

    Timchalk, Chuck; Trease, Harold E.; Trease, Lynn L.; Minard, Kevin R.; Corley, Rick A.

    2001-06-01

    Advances in computational, and imaging techniques have enabled the rapid development of 3-dimensional (3-D) models of biological systems in unprecedented detail. Using these advances, 3-D models of the lungs and nasal passages of the rat and human are being developed to ultimately improve predictions of airborne pollutant dosimetry. Techniques for imaging the respiratory tract by magnetic resonance (MR) imaging were developed to improve the speed and accuracy of geometric data collection for mesh reconstruction. The MR imaging resolution is comparable to that obtained by manual measurements but at much greater speed and accuracy. Newly developed software (NWGrid) was utilized to translate imaging data from MR into 3-D mesh structures. Together, these approaches significantly reduced the time to develop a 3-D model. This more robust airway structure will ultimately facilitate modeling gas or vapor exchange between the respiratory tract and vasculature as well as enable linkages of dosimetry with cell response models. The 3-D, finite volume, visco-elastic mesh structures forms the geometric basis for computational fluid dynamics modeling of inhalation, exhalation and the delivery of individual particles (or concentrations of gas or vapors) to discrete regions of the respiratory tract. The ability of these 3-D models to resolve dosimetry at such a high level of detail will require new techniques to measure regional airflows and particulate deposition for model validation.

  2. 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.

  3. Bifunctional AgCl/Ag composites for SERS monitoring and low temperature visible light photocatalysis degradation of pollutant

    NASA Astrophysics Data System (ADS)

    Dong, Lihong; Zhu, Junyi; Xia, Guangqing

    2014-12-01

    With the assistance of Polyvinylpyrrolidone (PVP), AgCl/Ag composites were fabricated in N, N-Dimethylformamide (DMF) solvent via a photoactivated route. The size of AgCl particles was in the range of 500 nm to 1 μm and the Ag particle's diameter was about 10-20 nm. Different from those core-shell structures reported before, the Ag nanoparticles were dispersed uniformly both on the surface and in the body of AgCl particles. The generation of such kind of composites was resulted from the reducing ability of DMF and light irradiation during the formation of AgCl particles. The as-obtained AgCl/Ag composites presented great activity for both surface-enhanced Raman scattering (SERS) detection and visible light photocatalytic degradation of organic dyes. Additionally, the AgCl/Ag composites could maintain high photocatalytic activity even though the ambient temperature was as low as 15 °C and recycle photocatalysis experiments indicated that the photocatalyst exhibited higher stability. Such kind of AgCl/Ag composites holds great potential for environmental monitoring devices and pollutant treatments.

  4. 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.)

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

    PubMed Central

    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. PMID:26628931

  6. 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.

  7. A contribution to the understanding of micro-pollutant sorption mechanisms in wastewater biological processes: case of the tributyltin.

    PubMed

    Bancon-Montigny, Chrystelle; Delalonde, Michèle; Rondet, Eric; Vachoud, Laurent; Grosmaire, Lidwine; Delarbre, Jean-Louis; Wisniewski, Christelle

    2012-01-01

    Micro-pollutant fluxes distribution throughout the physical separation and biological units of wastewater treatment plants (WWTPs) are very dependent ofsorption phenomena. The understanding and the control of the sorption stage is thus essential for the optimization of micro-pollutant removal in WWTPs, and particularly in biological treatments where these mechanisms influence the bioavailability towards micro-organisms. If the influence of the micro-pollutant physicochemical characteristics (e.g. Kow, pKa) on their ability to sorb on biological media (i.e. sludge) has been demonstrated, it appears that some other parameters, like the biosorbent characteristics, have to been taken into account. The aim of this study is thus to correlate the capacities of sorption of an environmentally relevant substance (tributyltin), with a thorough characterization of different types of sludge. The characterization of three biological media (raw, sonicated and flocculated activated sludges) is proposed according to various characterization parameters related to biochemical composition, aggregate size, rheological behaviour etc. The results show first that, whatever the sludge characteristics may be, the sorption mechanisms are very rapid and that an equilibrium state is reached after a few minutes. The influence of the sludge characteristics, notably the floc size and the chemical oxygen demand partition between solid and colloidal fraction, on sorption efficiency is demonstrated. A Langmuir modelling allows giving the maximum sorption capacity, as well as the binding energy for the three studied sludges, according to their physicochemical characteristics. PMID:23393963

  8. 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. PMID:26478374

  9. 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. PMID:26616746

  10. 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.

  11. 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

    2012-09-01

    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. PMID:22876912

  12. Towards engineering degradation of the explosive pollutant hexahydro-1,3,5-trinitro-1,3,5-triazine in the rhizosphere.

    PubMed

    Lorenz, Astrid; Rylott, Elizabeth L; Strand, Stuart E; Bruce, Neil C

    2013-03-01

    Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a serious environmental pollutant on military land. This compound is the most widely used explosive and pollution has arisen primarily as the result of military training, along with munition manufacturing and disassembly processes. This toxic explosive is recalcitrant to degradation in the environment and leaches rapidly into groundwater, where accumulation in aquifers is threatening drinking water supplies (Clausen, et al., 2004). While plants have only limited degradative activity towards RDX, microorganisms, including Rhodococcus rhodochrous 11Y, have been isolated from contaminated land. Despite the presence of microbial RDX-metabolising activity in contaminated soils, the persistence of RDX in leachate from contaminated soil indicates that this activity or biomass is insufficient, limiting its use to remediate polluted soils. Bacterial activity in the rhizosphere is of magnitudes greater than in the surrounding soil, and the roots of grass species on training ranges in the United States are known to penetrate deeply into the soil, producing a compact root system and providing an ideal environment to support the capture of RDX by microorganisms in the rhizosphere. Here, we have investigated the ability of the root-colonising bacterium Pseudomonas fluorescens, engineered to express XplA, to degrade RDX in the rhizosphere. PMID:23289483

  13. An overview on limitations of TiO2-based particles for photocatalytic degradation of organic pollutants and the corresponding countermeasures.

    PubMed

    Dong, Haoran; Zeng, Guangming; Tang, Lin; Fan, Changzheng; Zhang, Chang; He, Xiaoxiao; He, Yan

    2015-08-01

    The pollutants classified as "persistent organic pollutants (POPs)", are being subject to high concern among the scientific community due to their persistence in the environment. TiO2-based photocatalytic process has shown a great potential as a low-cost, environmentally friendly and sustainable treatment technology to remove POPs in sewage to overcome the shortcomings of the conventional technologies. However, this technology suffers from some main technical barriers that impede its commercialization, i.e., the inefficient exploitation of visible light, low adsorption capacity for hydrophobic contaminants, uniform distribution in aqueous suspension and post-recovery of the TiO2 particles after water treatment. To improve the photocatalytic efficiency of TiO2, many studies have been carried out with the aim of eliminating the limitations mentioned above. This review summarizes the recently developed countermeasures for improving the performance of TiO2-based photocatalytic degradation of organic pollutants with respect to the visible-light photocatalytic activity, adsorption capacity, stability and separability. The performance of various TiO2-based photocatalytic processes for POPs degradation and the underlying mechanisms were summarized and discussed. The future research needs for TiO2-based technology are suggested accordingly. This review will significantly improve our understanding of the process of photocatalytic degradation of POPs by TiO2-based particles and provide useful information to scientists and engineers who work in this field. PMID:25980914

  14. 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

  15. Complete and integrated pyrene degradation pathway in Mycobacterium vanbaalenii PYR-1 based on systems biology.

    PubMed

    Kim, Seong-Jae; Kweon, Ohgew; Jones, Richard C; Freeman, James P; Edmondson, Ricky D; Cerniglia, Carl E

    2007-01-01

    Mycobacterium vanbaalenii PYR-1 was the first bacterium isolated by virtue of its ability to metabolize the high-molecular-weight polycyclic aromatic hydrocarbon (PAH) pyrene. We used metabolic, genomic, and proteomic approaches in this investigation to construct a complete and integrated pyrene degradation pathway for M. vanbaalenii PYR-1. Genome sequence analyses identified genes involved in the pyrene degradation pathway that we have proposed for this bacterium. To identify proteins involved in the degradation, we conducted a proteome analysis of cells exposed to pyrene using one-dimensional gel electrophoresis in combination with liquid chromatography-tandem mass spectrometry. Database searching performed with the M. vanbaalenii PYR-1 genome resulted in identification of 1,028 proteins with a protein false discovery rate of <1%. Based on both genomic and proteomic data, we identified 27 enzymes necessary for constructing a complete pathway for pyrene degradation. Our analyses indicate that this bacterium degrades pyrene to central intermediates through o-phthalate and the beta-ketoadipate pathway. Proteomic analysis also revealed that 18 enzymes in the pathway were upregulated more than twofold, as indicated by peptide counting when the organism was grown with pyrene; three copies of the terminal subunits of ring-hydroxylating oxygenase (NidAB2, MvanDraft_0817/0818, and PhtAaAb), dihydrodiol dehydrogenase (MvanDraft_0815), and ring cleavage dioxygenase (MvanDraft_3242) were detected only in pyrene-grown cells. The results presented here provide a comprehensive picture of pyrene metabolism in M. vanbaalenii PYR-1 and a useful framework for understanding cellular processes involved in PAH degradation. PMID:17085566

  16. PROCEEDINGS OF THE SEMINAR ON BIOLOGICAL MONITORING AND ITS USE IN THE NPDES (NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM) PERMIT PROGRAM HELD AT CHICAGO, ILLINOIS ON OCTOBER 2, 1979

    EPA Science Inventory

    This seminar brought together representatives from industry, state and local governments and biological monitoring consulting firms to present the U.S. Environmental Protection Agency, Region V perspective on biomonitoring requirements for the National Pollutant Discharge Elimina...

  17. CONTROL OF BIOLOGICALLY ACTIVE DEGRADATION ZONES BY VERTICAL HETEROGENEITY: APPLICATIONS IN FRACTURED MEDIA

    EPA Science Inventory

    The U.S. Department of Energy (DOE) is faced with cleaning up wastes from reactor and weapons production activities during the latter half of this century. Many DOE sites have contaminants that are difficult to access due to depth and complex geology and are challenging to degrad...

  18. 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...

  19. Vector Biology: Tyrosine Degradation Protects Blood Feeders from Death via La Grande Bouffe.

    PubMed

    Kopáček, Petr; Perner, Jan

    2016-08-22

    Blood-feeding arthropods digest vast amounts of host-blood nutrients. A new study suggests that tyrosine degradation is essential for the survival of blood-fed kissing bugs, mosquitoes, and ticks. This finding presents a promising target for the control of these disease vectors. PMID:27554655

  20. Enhanced Fenton Catalytic Efficiency of γ-Cu-Al₂O₃ by σ-Cu²⁺-Ligand Complexes from Aromatic Pollutant Degradation.

    PubMed

    Lyu, Lai; Zhang, Lili; Wang, Qiyuan; Nie, Yulun; Hu, Chun

    2015-07-21

    Mesoporous Cu-doped γ-Al2O3 (γ-Cu-Al2O3) was prepared via an evaporation-induced self-assembly process, in which Cu(+/2+) was co-incorporated into mesoporous γ-Al2O3 by chemical bonding of Al-O-Cu. The catalyst was found to be highly effective and stable for the degradation and mineralization of aromatic pollutants, as demonstrated with bisphenol A, 2,4-dichlorophenoxyacetic acid, ibuprofen, diphenhydramine, and phenytoin in the presence of H2O2 under neutral pH conditions. In addition, the high utilization efficiency of H2O2 was maintained at approximately 90% prior to the disappearance of the initial aromatic pollutants. On the basis of all of the characterization results, the pollutant degradation processes predominantly occurred on the surface of the catalyst due to the formation of σ-Cu-ligand complexes between the phenolic OH group and the surface Cu. In the reaction system, in addition to the unselective oxidation by (•)OH, H2O2 directly attacked the σ-Cu(2+)-complexes aromatic ring with the phenolic OH group, which resulted in the formation of (•)OH and HO-adduct radicals that were oxidized to hydroxylation products by reduction of Cu(2+) in the σ-Cu(2+)-complexes to Cu(+). The process prevented Cu(2+) from oxidizing H2O2 to form HO2(•)/O2(•-) or O2, and enhanced the Cu(+)/Cu(2+) cycle, the formation of (•)OH, and the utilization efficiency of H2O2. Therefore, an extraordinarily high degradation and mineralization of the aromatic pollutants was observed. PMID:26101896

  1. 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.

  2. 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. PMID:26566643

  3. Micro-organic pollutants and biological response of mussels in marinas and ship building/breaking yards in Turkey.

    PubMed

    Okay, O S; Karacık, B; Güngördü, A; Ozmen, M; Yılmaz, A; Koyunbaba, N C; Yakan, S D; Korkmaz, V; Henkelmann, B; Schramm, K-W

    2014-10-15

    Concentrations of PAHs, PCBs and OCPs in sediments and mussels (caged and/or native) were determined at 16 stations in six major sites of coastal Turkey. The biological effects of pollution were evaluated using sediment toxicity tests and enzyme activity assays. EROD, PROD, GST, AChE, CaE, and GR activities were evaluated using the digestive glands of mussels. The total PAH concentrations in the sediments varied between nd and 79,674 ng g(-1) dw, while the total OCP concentrations were in the range of nd to 53.7 ng g(-1) dw. The total PAH concentrations in mussels varied between 22.3 and 37.4 ng g(-1) ww. The average concentrations of total PCBs in mussels were 2795 pg g(-1) ww in the shipyard, 797 pg g(-1) ww in Marina 2 and 53 pg g(-1) ww in Marina 1 stations. The results of whole-sediment toxicity tests showed a strong correlation between toxicity test results and pollutant concentrations. Selected cytosolic enzyme activities in digestive glands differed significantly depending on localities. These differences in enzyme activities were mainly related to the different pollutant levels of the sampling sites. The micro-organic contaminant profile patterns, toxicity tests and biomarker studies showed that shipyards and shipbreaking yards are the major potential sources of organic pollution in coastal areas. PMID:25079235

  4. 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). PMID:25262485

  5. Effect of the pollution level on the functional bacterial groups aiming at degrading bisphenol A and nonylphenol in natural biofilms of an urban river.

    PubMed

    Cai, Wei; Li, Yi; Wang, Peifang; Niu, Lihua; Zhang, Wenlong; Wang, Chao

    2016-08-01

    Bisphenol A (BPA) and 4-nonylphenol (NP) are ubiquitous pollutants with estrogenic activity in aquatic environment and have attracted global concern due to their disruption of endocrine systems. This study investigated the spatial distribution characteristics of the bacterial groups involved in the degradation of BPA and NP within biofilms in an urban river using terminal restriction fragment length polymorphism based on 16S rRNA gene sequences. The effects of the pollution level and water parameters on these groups were also assessed. Hierarchical cluster analysis grouped the sampling sites into three clusters reflecting their varying nutrient pollution levels of relatively slight pollution (SP), moderate pollution (MP), and high pollution (HP) based on water quality data and Environmental Quality Standard for Surface Water of China (GB3838-2002). The BPA and NP concentration in river water ranged from 0.8 to 77.5 and 10.2 to 162.9 ng L(-1), respectively. Comamonadaceae, Pseudomonadaceae, Alcaligenaceae, Bacillaceae, Sphingomonadacea, Burkholderiaceae, and Rhizobiaceae were the dominant bacterial taxa involved in BPA and NP degradation, comprising an average of 9.8, 8.1, 7.6, 6.7, 6.2, 4.1, and 2.8 % of total sequences, respectively. The total abundance of these groups showed a slight upward trend and subsequently rapidly decreased with increasing pollution levels. The average proportion of Comamonadaceae in MP river sections was almost 1.5-2 times than that in SP or HP one. The distribution of functional groups was found related to environmental variables, especially pH, conductivity, ammonium nitrogen (NH3-N), and BPA. The abundance of Comamonadaceae and Rhizobiaceae was both closely related to higher values of pH and conductivity as well as lower concentrations of NP and BPA. Alcaligenaceae and Pseudomonadaceae were associated with higher concentrations of TP and CODMn and inversely correlated with DO concentration. This study might provide effective data on

  6. 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. PMID:16001393

  7. 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.

  8. 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. PMID:24548886

  9. 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. PMID:27288657

  10. 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

  11. Bacterial Communities in Polluted Seabed Sediments: A Molecular Biology Assay in Leghorn Harbor

    PubMed Central

    Verni, Franco; Petroni, Giulio

    2013-01-01

    Seabed sediments of commercial ports are often characterized by high pollution levels. Differences in number and distribution of bacteria in such areas can be related to distribution of pollutants in the port and to sediment conditions. In this study, the bacterial communities of five sites from Leghorn Harbor seabed were characterized, and the main bacterial groups were identified. T-RFLP was used for all samples; two 16S rRNA libraries and in silico digestion of clones were used to identify fingerprint profiles. Library data, phylogenetic analysis, and T-RFLP coupled with in silico digestion of the obtained sequences evidenced the dominance of Proteobacteria and the high percentage of Bacteroidetes in all sites. The approach highlighted similar bacterial communities between samples coming from the five sites, suggesting a modest differentiation among bacterial communities of different harbor seabed sediments and hence the capacity of bacterial communities to adapt to different levels and types of pollution. PMID:24227997

  12. 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. PMID:25752833

  13. 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.'

  14. 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

  15. 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. PMID:24487942

  16. Biological cycling of carbon and nitrogen to reduce agricultural pollution by nutrients

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Carbon and nitrogen are two key elements of global significance, playing large roles in the production of food, feed, fiber, and fuel for human existence, as well as providing numerous other ecosystem services. Although nitrogen is often a limiting element in natural systems, it can become a pollut...

  17. 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)...

  18. COGNITIVE DECLINE, CARDIOVASCULAR CHANGES, AND BIOLOGICAL AGING IN RESPONSE TO AIR POLLUTION

    EPA Science Inventory

    We have already reported different associations of traffic vs. secondary particles and ozone with different endpoints. With better exposure characterization and longer follow-up we will identify the key aspects of pollution that drive the association with cognition, inflammati...

  19. 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. PMID:25690303

  20. 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.

  1. 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

    2016-02-01

    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 × 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. PMID:26590282

  2. 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

  3. Biological functioning of PAH-polluted and thermal desorption-treated soils assessed by fauna and microbial bioindicators.

    PubMed

    Cébron, Aurélie; Cortet, Jérôme; Criquet, Stéven; Biaz, Asmaa; Calvert, Virgile; Caupert, Cécile; Pernin, Céline; Leyval, Corinne

    2011-11-01

    A large number of soil bioindicators were used to assess biological diversity and activity in soil polluted with polycyclic aromatic hydrocarbons (PAHs) and the same soil after thermal desorption (TD) treatment. Abundance and biodiversity of bacteria, fungi, protozoa, nematodes and microarthropods, as well as functional parameters such as enzymatic activities and soil respiration, were assessed during a two year period of in situ monitoring. We investigated the influence of vegetation (spontaneous vegetation and Medicago sativa) and TD treatment on biological functioning. Multivariate analysis was performed to analyze the whole data set. A principal response curve (PRC) technique was used to evaluate the different treatments (various vegetation and contaminated vs. TD soil) contrasted with control (bare) soil over time. Our results indicated the value of using a number of complementary bioindicators, describing both diversity and functions, to assess the influence of vegetation on soil and discriminate polluted from thermal desorption (TD)-treated soil. Plants had an influence on the abundance and activity of all organisms examined in our study, favoring the whole trophic chain development. However, although TD-treated soil had a high abundance and diversity of microorganisms and fauna, enzymatic activities were weak because of the strong physical and chemical modifications of this soil. PMID:21392572

  4. 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.

  5. 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.

  6. Biological degradation and greenhouse gas emissions during pre-storage of liquid animal manure.

    PubMed

    Møller, Henrik B; Sommer, Sven G; Ahring, Birgitte K

    2004-01-01

    Storage of manure makes a significant contribution to global methane (CH4) emissions. Anaerobic digestion of pig and cattle manure in biogas reactors before outside storage might reduce the potential for CH4 emissions. However, manure pre-stored at 15 to 20 degrees C in buildings before anaerobic digestion may be a significant source of CH4 and could reduce the potential CH4 production in the biogas reactor. Degradation of energy-rich organic components in slurry and emissions of CH4 and carbon dioxide (CO2) from aerobic and anaerobic degradation processes during pre-storage were examined in the laboratory. Newly mixed slurry was added to vessels and stored at 15 and 20 degrees C for 100 to 220 d. During storage, CH4 and CO2 emissions were measured with a dynamic chamber technique. The ratio of decomposition in the subsurface to that at the surface indicated that the aerobic surface processes contributed significantly to CO2 emission. The measured CH4 emission was used to calculate the methane conversion factor (MCF) in relation to storage time and temperature, and the total carbon-C emission was used to calculate the decrease in potential CH4 production by anaerobic digestion following pre-storage. The results show substantial methane and carbon dioxide production from animal manure in an open fed-batch system kept at 15 to 20 degrees C, even for short storage times, but the influence of temperature was not significant at storage times of <30 d. During long-term storage (90 d), a strong influence of temperature on the MCF value, especially for pig manure, was observed. PMID:14964355

  7. BIODEGRADATION OF ENVIRONMENTAL POLLUTANTS BY THE WHITE ROT FUNGUS PHANEROCHATETE CHRYSOSPORIUM: INVOLVEMENT OF THE LIGNIN DEGRADING SYSTEM

    EPA Science Inventory

    The white-rot fungus Phanerochaete chrysosporium has the ability to degrade's wide variety of structurally diverse organic compounds, including a number of environmentall3 persistent organopollutants. he unique biodegradative abilities of this fungus appears to be dependent upon ...

  8. Formulation of economical microbial feed using degraded chicken feathers by a novel Streptomyces sp: mitigation of environmental pollution

    PubMed Central

    Ramakrishnan, Jayapradha; Balakrishnan, Hariram; Raja, Selvaraj Thirupathi Kumara; Sundararamakrishnan, Natarajan; Renganathan, Sadagoban; Radha, Venkatesh Nagarajan

    2011-01-01

    A new Streptomyces sp. IF 5 was isolated from the feather dumped soil and found to have a tremendous keratinase activity. The strain enabled the degradation of the chicken feathers very effectively in 60 h. The 16S rRNA sequence of 1474 bp long was submitted to the National centre for Biotechnological information. The keratinolytic activity in the culture medium was 1181 U/ml. The release and analyses of sulphydryl groups in the culture medium evident the degradation activity by the Streptomyces sp. IF 5. The idea of the present study was to use the degraded chicken feathers as the substrate for the growth and cultivation of microorganisms. We have designed a very economical culture medium that includes the usage of some basal salts alone and degraded chicken feathers (10 g/l). The results of the specific growth rate of the tested microbes confirm the usage of the new designed medium for microbial culturing. PMID:24031698

  9. 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.

  10. Relation between biological testing and standardization and toxicological control of pollution of water bodies

    SciTech Connect

    Filenko, O.F.

    1986-03-01

    In aquatic toxicology, biotesting means an evaluation of the toxic properties of substances present in water on the basis of the reactions or aquatic organisms. Toxicological biotesting is the basis for two important elements of limiting environmental pollution -- toxicological standardization and toxicological control. The development of toxicological control does not eliminate the need for conducting systematic chronic investigations for purposes of standardization but uses them as its basis. It is necessary to develop toxicological control methods for a multitude of substances or wastewaters capable of polluting water bodies. A table illustrates the allowable concentrations of triethyltin chloride (TETC), tripropyltin chloride (TPTC), triphenyltin chloride (T PhTC), and trihexyltin chloride (THTC) for aquatic organisms.

  11. Caddisfly larvae as biological indicators of Pb pollution in an Austrian river

    SciTech Connect

    Koeck, G.; Pesendorfer, C.; Hofer, R.

    1995-12-31

    Caddisfly larvae (Trichoptera, Limnephilidae) were used as biomonitors of Pb pollution in an Austrian river. Pb-contaminated industrial effluents from a glass-manufacturing firm led to very high Pb concentrations in the sediment (up to 1,400 {micro}g.g{sup {minus}1} Pb, dry weight, in the clay fraction). Pb concentration in pooled samples of insect larvae from different sites were investigated during three consecutive years (1990--1992) to study time trends of Pb contamination after installation of a water purification plant (end of 1990). In 1990 Pb concentration of larvae from a sampling site downstream close to the pollution source were magnitudes higher (276 {micro}g.g{sup {minus}1} Pb, dry weight) than at an upstream reference site (6 {micro}g g{sup {minus}1} Pb, dry weight). However, after installation of the water purification plant, Pb concentration in caddisfly larvae decreased continuously by a constant rate of 64% per year. In 1992 Pb burden of the larvae amounted to only 13% of the Pb concentration in 1990. Pb burden of caddisfly larvae reflected the Pb contamination of the river even in 60 km distance from the pollution source. The study indicates caddisfly larvae to be valuable biomonitoring organisms of metal contamination in freshwater ecosystems.

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

    PubMed

    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; Ferrer, Manuel; Golyshin, Peter N

    2015-10-01

    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

  13. 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

  14. 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. PMID:26921849

  15. 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. PMID:25312333

  16. 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. PMID:26359182

  17. 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.

  18. A simple Cr(VI)-S(IV)-O2 system for rapid and simultaneous reduction of Cr(VI) and oxidative degradation of organic pollutants.

    PubMed

    Yuan, Yanan; Yang, Shaojie; Zhou, Danna; Wu, Feng

    2016-04-15

    Hexavalent chromium (Cr(VI)), a heavy-metal contaminant, can be easily reduced to less toxic trivalent chromium (Cr(III)) by sulfite ions (S(IV)). However, S(IV) has not drawn as much attention as the ferrous ion has. We report herein a novel Cr(VI)-S(IV)-O2 system containing sulfite ions that rapidly and simultaneously reduces Cr(VI) and oxidize organic pollutants in the presence of oxygen in aqueous solutions. This Cr(VI)-S(IV)-O2 system contains the initiator Cr(VI), the reductant S(IV), and the oxidant O2, which produce oxysulfur radicals (mainly SO4(-) and SO5(-)) and hydroxyl radicals (OH). The Cr(VI)/S(IV) molar ratio, pH, and oxygen content play important roles in the entire reaction system. Acidic conditions (pH 3.0) facilitated degradation of organic compounds and reduction of Cr(VI) as well. In addition, experiments of rapid degradation of several kinds of organic pollutants such as azo dye (acid orange 7, AO7), aniline, phenol, bisphenol A etc were also conducted. Preliminary results show that the removal rates of the analogs of phenols or aromatic amines in this Cr(VI)-S(IV)-O2 system have a relationship with the electronic parameters (Hammett constant, σ) of the substituted groups. Thus, the Cr(VI)-S(IV)-O2 system, provides an excellent strategy of "waste control by waste" for removing multiple industrial contaminants. PMID:26799220

  19. Bismuth oxychloride modified titanium phosphate nanoplates: A new p-n type heterostructured photocatalyst with high activity for the degradation of different kinds of organic pollutants.

    PubMed

    Ao, Yanhui; Bao, Jiaqiu; Wang, Peifang; Wang, Chao; Hou, Jun

    2016-08-15

    In this work, BiOCl modified titanium phosphate nanoplates (BiOCl/TP) composite photocatalysts with p-n heterojunctions were prepared by a in-situ growth method. The morphology, crystal structure and optical properties of the prepared samples were characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray diffraction (XRD), UV-vis diffuse reflectance spectrometry (DRS). Rhodamine B (RhB), reactive brilliant Red X-3B (X-3B), methylene blue (MB), ciprofloxacin (CIP) and phenol were used to investigate the photocatalytic performance of the prepared samples under ultraviolet light irradiation. Results showed that the BiOCl/TP exhibited much higher activity for the degradation of all these model organic pollutants than pure TP. The mechanism for the enhancement of the photocatalytic performance was established with the help of the results of photocurrent measurements and Photoluminescence spectra. The results illustrated that the enhanced activity could be attributed to the formation of p-n heterojunctions between p-type BiOCl and n-type titanium phosphate, which effectively suppressed the recombination of photo-induced electron-hole pairs. Furthermore, the possible photocatalytic mechanisms on the degradation of the organic pollutants were also proposed. PMID:27209392

  20. 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. PMID:27016882

  1. Photodegradation of fluorene in aqueous solution: Identification and biological activity testing of degradation products.

    PubMed

    Kinani, Said; Souissi, Yasmine; Kinani, Aziz; Vujović, Svetlana; Aït-Aïssa, Sélim; Bouchonnet, Stéphane

    2016-04-15

    Degradation of fluorene under UV-vis irradiation in water was investigated and structural elucidation of the main photoproducts was achieved using gas chromatography coupled with mass spectrometry. Twenty-six photoproducts were structurally identified, mainly on the basis of electron ionization mass spectra interpretation. The main generated transformation products are hydroxy derivatives. Some secondary photoproducts including fluorenone, hydroxy fluorenone, 2-biphenyl carboxylic acid, biphenylene, methanol fluorene congeners and hydroxy fluorene dimers were also observed. A photodegradation pathway was suggested on the basis of the chemical structures of photoproducts. Fluorene as well as its main photoproducts for which chemical standards were commercially available were tested for their ability to elicit cytotoxic, estrogenic and dioxin-like activity by using in vitro cell-based bioassays. None of the tested compounds was cytotoxic at concentrations up to 100μM. However, 2-hydroxyfluorene and 3-hydroxyfluorene exerted significant estrogenic and dioxin-like activity on a concentration range of 3-30μM, while fluorene and 9-hydroxyfluorene were weakly or not active, respectively, in our assays. This supports the view that photodegradation processes can generate by-products of higher toxicological concern than the parent compound and strengthens the need to further identify transformation products in the aquatic environment. PMID:26987414

  2. Biological effect of radiation-degraded alginate on flower plants in tissue culture.

    PubMed

    Le, Q Luan; Nguyen, Q Hien; Nagasawa, Naotsugu; Kume, Tamikazu; Yoshii, Fumio; Nakanishi, Tomoko M

    2003-12-01

    Alginate with a weight-average molecular mass (Mw) of approx. 9.04 x 10(5) Da was irradiated at 10-200 kGy in 4% (w/v) aqueous solution. The degraded alginate product was used to study its effectiveness as a growth promoter for plants in tissue culture. Alginate irradiated at 75 kGy with an Mw of approx. 1.43 x 10(4) Da had the highest positive effect in the growth of flower plants, namely limonium, lisianthus and chrysanthemum. Treatment of plants with irradiated alginate at concentrations of 30-200 mg/l increased the shoot multiplication rate from 17.5 to 40.5% compared with control. In plantlet culture, 100 mg/l irradiated alginate supplementation enhanced shoot height (9.7-23.2%), root length (9.7-39.4%) and fresh biomass (8.1-19.4%) of chrysanthemum, lisianthus and limonium compared with that of the untreated control. The survival ratios of the transferred flower plantlets treated with irradiated alginate were almost the same as the control value under greenhouse conditions. However, better growth was attained for the treated plantlets. PMID:12901723

  3. 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. PMID:26363258

  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. 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. PMID:22297224

  6. 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. PMID:18814290

  7. BIOLOGICAL SIGNIFICANCE OF SOME METALS AS AIR POLLUTANTS. PART II. MERCURY

    EPA Science Inventory

    The study was undertaken in order to elucidate the association between low atmospheric mercury levels and changes in some biological parameters likely to react to such exposures. The study covered four populations believed to be exposed to four different levels of atmospheric mer...

  8. Ternary ZnO/Ag3VO4/Fe3O4 nanocomposites: Novel magnetically separable photocatalyst for efficiently degradation of dye pollutants under visible-light irradiation

    NASA Astrophysics Data System (ADS)

    Shekofteh-Gohari, Maryam; Habibi-Yangjeh, Aziz

    2015-10-01

    In this work, we successfully prepared a series of novel magnetically separable ZnO/Ag3VO4/Fe3O4 nanocomposites by a facile refluxing method using Fe3O4, zinc nitrate, silver nitrate, ammonium metavanadate, and sodium hydroxide as starting materials without using any post preparation treatments. The microstructure, purity, morphology, spectroscopic, and magnetic properties of the prepared samples were studied using XRD, EDX, SEM, TEM, UV-vis DRS, FT-IR, PL, and VSM techniques. The ZnO/Ag3VO4/Fe3O4 nanocomposite with 8:1 weight ratio of ZnO/Ag3VO4 to Fe3O4 has the superior activity in degradation of rhodamine B under visible-light irradiation. Photocatalytic activity of this nanocomposite is about 11.5-fold higher than that of the ZnO/Fe3O4 nanocomposite. The results showed that the preparation time and calcination temperature significantly affect on the photocatalytic activity. The trapping experiments revealed that superoxide ions and holes have major influence on the degradation reaction. Furthermore, the enhanced activity of the nanocomposite for degradation of two more dye pollutants was confirmed. Finally, the nanocomposite was magnetically separated from the treated solution after four successive cycles.

  9. Preparation of new magnetic nanocatalysts based on TiO2 and ZnO and their application in improved photocatalytic degradation of dye pollutant under visible light.

    PubMed

    Nabid, Mohammad Reza; Sedghi, Roya; Gholami, Saeede; Oskooie, Hossein Abdi; Heravi, Majid M

    2013-01-01

    Photocatalytic degradation of methyl orange (MO) as a model of an organic pollution was accomplished with magnetic and porous TiO(2)/ZnO/Fe(3)O(4)/PANI and ZnO/Fe(3)O(4)/PANI nanocomposites under visible light irradiation. The structures of nanocomposites were characterized by various techniques including UV-Vis absorption spectroscopy, XRD, SEM, EDS, BET and TGA. Optical absorption investigations show two λ(max) at 450 and 590 nm for TiO(2)/ZnO/Fe(3)O(4)/PANI nanocomposites respectively possessing optical band gaps about 2.75 and 2.1 eV smaller than that of the neat TiO(2) and ZnO nanoparticles. Due to these optical absorptions, the nanocomposites can be considered promising candidates as visible light photocatalysts to produce more electron-hole pairs. The degradation of MO, extremely increased using polymeric photocatalysts and decolorization in the presence of visible light achieved up to 90% in less than 20 min in comparison with the neat nanoparticles (about 10%). All these advantages promise a bright future for these composites as useful photocatalysts. The degradation efficiency of MO using stable nanocomposites was still over 70% after ten times reusing. The highest decolorizing efficiencies were achieved with 0.75 g L(-1) of catalyst and 10 mg L(-1) of MO at natural pH under visible light irradiation in less than 20 min. PMID:22817280

  10. 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.