Science.gov

Sample records for humic acid-sorbed phenanthrene

  1. The influence of mechanochemical modification on prevention of toxic ability of humic acids towards phenanthrene in aquatic environment

    NASA Astrophysics Data System (ADS)

    Shekhovtsova, N. S.; Maltseva, E. V.; Glyzina, T. S.; Ovchinnikova, I. S.

    2015-11-01

    The aim of the research work is to quantify interaction between phenanthrene with modified humic acids in aquatic environment. The changes in the structure and properties of humic acids after modifications were studied with 1H NMR spectroscopy and potentiometric titration methods. Our research demonstrates that the application of thiourea as a modified agent increases the binding capacity of humic acids towards phenanthrene.

  2. Effect of solution chemistry on the extent of binding of phenanthrene by a soil humic acid: A comparison of dissolved and clay bound humic

    SciTech Connect

    Jones, K.D.; Tiller, C.L.

    1999-02-15

    The effect of pH, ionic strength, and cation in solution on the binding of phenanthrene by a soil humic acid in the aqueous phase was determined using fluorescence quenching. The phenanthrene binding coefficient with the dissolved soil humic, K{sub oc}, decreased with increasing ionic strength and solution cation valence. At low values of ionic strength, K{sub oc} values for this soil humic acid increased with increasing pH. For this humic sample, the experimental results were consistent with a conformational model of the humic substance in aqueous solution where, depending on solution conditions, some parts of the humic structure may be more open to allow increased PAH access to attachment sites. After sorption onto clays, supernatant solutions of the unadsorbed humic fraction yielded lower K{sub oc} values than the original bulk humic acid, suggesting that the humic substance was fractionating during its sorption onto the clays. Additionally, the extent of phenanthrene binding with the adsorbed humic fraction was lower than the results determined for the bulk humic acid prior to adsorption. The conformation of the humic substance when sorbed onto the inorganic surface appears to be affecting the level of phenanthrene binding by the humic acid.

  3. Bioavailability of labile and desorption-resistant phenanthrene sorbed to montmorillonite clay containing humic fractions

    SciTech Connect

    Lahlou, M.; Ortega-Calvo, J.J.

    1999-12-01

    The biodegradation of {sup 14}C-labeled phenanthrene in the presence of particles of montmorillonite and fulvic and humic acid-montmorillonite complexes was studied in a batch system. A mathematical model that takes into account the contribution to mineralization by the slowly desorbing compound was used to calculate the initial mineralization rates. Sorption of phenanthrene to the particles was determined in sorption isotherms, and desorption was measured during successive water extractions. Mineralization rates in equilibrated suspensions were higher than predicted from aqueous equilibrium concentrations, and in some cases, montmorillonite and fulvic acid-montmorillonite complexes stimulated the phenanthrene transformation rates. In contrast with the high bioavailability exhibited by phenanthrene sorbed as a labile form, biodegradation of the desorption-resistant phenanthrene occurred slowly and followed zero-order kinetics, which indicated a limitation caused by slow desorption. The results suggest that the mechanism of sorption may cause a differential bioavailability of the sorbed compound.

  4. Effect of humic fractions and clay on biodegradation of phenanthrene by a Pseudomonas fluorescens strain isolated from soil

    SciTech Connect

    Ortega-Calvo, J.J.; Saiz-Jimenez, C.

    1998-08-01

    The mineralization of phenanthrene in pure cultures of a Pseudomonas fluorescens strain, isolated from soil, was measured in the presence of soil humic fractions and montmorillonite. Humic acid and clay, either separately or in combination, shortened the acclimation phase. A higher mineralization rate was measured in treatments with humic acid at 100 {micro}g/ml. Humic acid at 10 {micro}g/ml stimulated the transformation only in the presence of 10 g of clay per liter. The authors suggest that sorption of phenanthrene to these soil components may result in a higher concentration of substrate in the vicinity of the bacterial cells and therefore may increase its bioavailability.

  5. Use of humic acids derived from peat and lignite as phenanthrene sorbents

    NASA Astrophysics Data System (ADS)

    Sofikitis, Elias; Giannouli, Andriana; Kalaitzidis, Stavros; Christanis, Kimon; Karapanagioti, Hrissi K.; Papanicolaou, Cassiani

    2015-04-01

    A broad range of materials is being applied for environmental remediation of water, among them sorbents such as humic acids. Being natural substances, the extraction and purification of humic acids might be cheaper than the production of synthetic sorbents. Having higher absorbing capacity than most of the sorbents used to date, humic acids have a competitive advantage against commonly used sorbents such as active charcoals and biochar. Humic acids are "complex colloidal super-mixtures" that are characterized by their functional groups. Therefore, composition and molecular formula can vary depending on the properties of the parent material. The aim of this project was (a) to study the sorption capacity of humic acids derived from peat and lignite samples picked up from deposits spread throughout Greece and (b) to compare the results with these of the parent materials. This comparison provides an insight to which matrix samples are suitable for further chemical treatment for the isolation of humic acids to be used as sorbents. The selected model pollutant was phenanthrene, which is a PAH that consists of three fused benzene rings. Humic acids were extracted according to the methodology proposed by the IHSS, slightly modified, in order to fit better to the properties of organic sediments. Sorption experiments were conducted by mixing 0.004 g of the sorbent (peat or lignite or humic acid) with aqueous solutions of phenanthrene at different concentrations of 30, 50, 100, 300, and 500 μg/L. The results show that phenanthrene sorption is higher for the humic acid than for the original lignite and peat samples. The original samples display higher sorption at the lower phenanthere solutions (30 μg/L; Kd ranges from 15,000 to 47,000 L/kg) than at the higher one (500 μg/L; Kd ranges from 4,100 to 13,000 L/Kg) suggesting non-linear sorption. The humic acids display mainly linear isotherms with Kd ranges from 6,600 to 120,000 L/kg. Concerning the suitability of the studied

  6. Phenanthrene binding by humic acid-protein complexes as studied by passive dosing technique.

    PubMed

    Zhao, Jian; Wang, Zhenyu; Ghosh, Saikat; Xing, Baoshan

    2014-01-01

    This work investigated the binding behavior of phenanthrene by humic acids (HA-2 and HA-5), proteins (bovine serum albumin (BSA)), lysozyme and pepsin), and their complexes using a passive dosing technique. All sorption isotherms were fitted well with Freundlich model and the binding capability followed an order of HA-5 > HA-2 > BSA > pepsin > lysozyme. In NaCl solution, phenanthrene binding to HA-BSA complexes was much higher than the sum of binding to individual HA and BSA, while there was no enhancement for HA-pepsin. Positively charged lysozyme slightly lowered phenanthrene binding on both HAs due to strong aggregation of HA-lysozyme complexes, leading to reduction in the number of binding sites. The binding enhancement by HA-BSA was observed under all tested ion species and ionic strengths. This enhancement can be explained by unfolding of protein, reduction of aggregate size and formation of HA-BSA complexes with favorable conformations for binding phenanthrene.

  7. Mechanisms regulating bioavailability of phenanthrene sorbed on a peat soil-origin humic substance.

    PubMed

    Yang, Yu; Shu, Liang; Wang, Xilong; Xing, Baoshan; Tao, Shu

    2012-07-01

    The organic matter-mineral complex plays an important role in regulating the fate of hydrophobic organic compounds (HOCs) in the environment. In the present study, the authors investigated the microbial bioavailability of phenanthrene (PHE) sorbed on the original and demineralized humic acids (HAs) and humin (HM) that were sequentially extracted from a peat soil. Demineralization treatment dramatically decreased the 720-h mineralized percentage of HM-sorbed PHE from 42.5 ± 2.6% to 3.4 ± 1.3%, whereas the influence of this treatment on the biodegradability of HA-associated PHE was much lower. Degradation kinetics of HA- and HM-sorbed PHE showed that its initial degradation rate was negatively correlated with the aromatic carbon content of humic substances (p<0.05). This was attributed to the strong interactions between PHE and the aromatic components of humic substances, which hampered its release and subsequent biodegradation. The 720-h mineralized percentage of PHE was inversely correlated with the estimated thickness of the organic matter layer at the surfaces of HAs and HMs. Therefore, in a relatively long term, diffusion of PHE within the organic matter layer could be an important factor that may limit the bioavailability of PHE to bacteria. Results of the present study highlight the molecular-scaled mechanisms governing bioavailability of PHE sorbed on humic substances.

  8. Hydroxypropyl-β-cyclodextrin extractability and bioavailability of phenanthrene in humin and humic acid fractions from different soils and sediments.

    PubMed

    Gao, Huipeng; Ma, Jing; Xu, Li; Jia, Lingyun

    2014-01-01

    Organic matter (OM) plays a vital role in controlling polycyclic aromatic hydrocarbon (PAH) bioavailability in soils and sediments. In this study, both a hydroxypropyl-β-cyclodextrin (HPCD) extraction test and a biodegradation test were performed to evaluate the bioavailability of phenanthrene in seven different bulk soil/sediment samples and two OM components (humin fractions and humic acid (HA) fractions) separated from these soils/sediments. Results showed that both the extent of HPCD-extractable phenanthrene and the extent of biodegradable phenanthrene in humin fraction were lower than those in the respective HA fraction and source soil/sediment, demonstrating the limited bioavailability of phenanthrene in the humin fraction. For the source soils/sediments and the humin fractions, significant inverse relationships were observed between the sorption capacities for phenanthrene and the amounts of HPCD-extractable or biodegradable phenanthrene (p < 0.05), suggesting the importance of the sorption capacity in affecting desorption and biodegradation of phenanthrene. Strong linear relationships were observed between the amount of HPCD-extractable phenanthrene and the amount degraded in both the bulk soils/sediments and the humin fractions, with both slopes close to 1. On the other hand, in the case of phenanthrene contained in HA, a poor relationship was observed between the amount of phenanthrene extracted by HPCD and the amount degraded, with the former being much less than the latter. The results revealed the importance of humin fraction in affecting the bioavailability of phenanthrene in the bulk soils/sediments, which would deepen our understanding of the organic matter fractions in affecting desorption and biodegradation of organic pollutants and provide theoretical support for remediation and risk assessment of contaminated soils and sediments.

  9. Investigating the role of mineral-bound humic acid in phenanthrene sorption.

    PubMed

    Feng, Xiaojuan; Simpson, André J; Simpson, Myrna J

    2006-05-15

    Contaminant-soil interaction studies have indicated that physical conformation of organic matter atthe solid-aqueous interface is important in governing hydrophobic organic compound (HOC) sorption. To testthis, organo-clay complexes were constructed by coating montmorillonite and kaolinite with peat humic acid (PHA) in Na+ or Ca2+ dominated solutions with varying pH and ionic strength values. The solution conditions encouraged the dissolved PHA to adopt a "coiled" or "stretched" conformation prior to interacting with the clay mineral surface. Both kaolinite and montmorillonite organo-clay complexes exhibited higher phenanthrene sorption (Koc values) with decreasing pH, indicating that the coiled configuration provided more favorable sorption conditions. Evidence from 1H high-resolution magic angle spinning (HR-MAS) nuclear magnetic resonance (NMR) indicated that polymethylene groups were prevalent at the surface of the organo-clay complexes and may enhance sorptive interactions. Preferential sorption of polymethylene groups on kaolinite and aromatic compounds on montmorillonite may also contribute to the difference in phenanthrene sorption by PHA associated with these two types of clay. This study demonstrates the importance of solution conditions in the sorption of nonionic, hydrophobic organic contaminants and also provides evidence for the indirect role of clay minerals in sorption of contaminants at the soil-water interface.

  10. Phenanthrene

    Integrated Risk Information System (IRIS)

    Phenanthrene ; CASRN 85 - 01 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effec

  11. Influences of humic acid on the bioavailability of phenanthrene and alkyl phenanthrenes to early life stages of marine medaka (Oryzias melastigma).

    PubMed

    Liu, Yangzhi; Yang, Chenghu; Cheng, Pakkin; He, Xiaojing; Zhu, Yaxian; Zhang, Yong

    2016-03-01

    The influences of humic acid (HA) on the environmental behavior and bioavailability of parent polycyclic aromatic hydrocarbons (PAHs) and alkyl PAHs were investigated and compared using the early life stages of marine medaka (Oryzias melastigma, O. melastigma). It was demonstrated that the binding affinity of parent phenanthrene (PHE) with HA was smaller than that of 3-methyl phenanthrene (3-MP) and 9-ethyl phenanthrene (9-EP). Furthermore, the bioaccumulation of the three PAHs and the levels of lipid peroxidation (LPO) were calculated to study the changes in bioavailability of PAHs in presence of HA. The results indicated that the addition of HA significantly decreased the bioaccumulation and toxicity of PAHs by decreasing free PAHs concentrations. The bioavailable fractions of HA-bound PAHs in bioaccumulation (α) and toxicity (β) were evaluated, indicating that the HA-bound 3-MP and 9-EP show higher bioavailability in bioaccumulation and lower bioavailability in toxicity relative to those of PHE. The β/α values were less than 1 for all PAH treatment groups containing HA, suggesting that the fraction of HA-bound PAHs contributing to bioaccumulation was higher than that of HA-bound PAHs inducing toxic effect. In addition, we proposed that the free PAHs generated by desorption from HA in the cell were toxic by showing that the β/α ratio values are correlated with the log KOW values (p = 0.007 and R(2) = 0.8355). Thus, oil spill risk assessments should consider both alkyl PAHs and the factors that influence the bioavailability and toxicity of PAHs in the natural aquatic environments.

  12. Effect of cosolutes on the sorption of phenanthrene onto mineral surface of river sediments and kaolinite.

    PubMed

    Wu, Yinghong; Liu, Fang; Zhang, Wen; Wang, Lei

    2014-01-01

    Sorption of phenanthrene onto the natural sediment with low organic carbon content (OC%), organic-free sediment, and kaolinite was investigated through isotherm experiments. Effects of cosolutes (pyrene, 4-n-nonyphenol (NP), and humic acid (HA)) on phenanthrene sorption were also studied by comparing apparent solid-water distribution coefficients (K d (app)) of phenanthrene. Two addition sequences, including "cosolute added prior to phenanthrene" and "cosolute and phenanthrene added simultaneously," were adopted. The Freundlich model fits phenanthrene sorption on all 3 sorbents well. The sorption coefficients on these sorbents were similar, suggesting that mineral surface plays an important role in the sorption of hydrophobic organic contaminants on low OC% sediments. Cosolutes could affect phenanthrene sorption on the sorbents, which depended on their properties, concentrations, and addition sequences. Pyrene inhibited phenanthrene sorption. Sorbed NP inhibited phenanthrene sorption at low levels and promoted sorption at high levels. Similar to NP, effect of HA on phenanthrene sorption onto the natural sediment depended on its concentrations, whereas, for the organic-free sediment and kaolinite, preloading of HA at high levels led to an enhancement in phenanthrene K d (app) while no obvious effect was observed at low HA levels; dissolved HA could inhibit phenanthrene sorption on the two sorbents.

  13. Effect of Cosolutes on the Sorption of Phenanthrene onto Mineral Surface of River Sediments and Kaolinite

    PubMed Central

    2014-01-01

    Sorption of phenanthrene onto the natural sediment with low organic carbon content (OC%), organic-free sediment, and kaolinite was investigated through isotherm experiments. Effects of cosolutes (pyrene, 4-n-nonyphenol (NP), and humic acid (HA)) on phenanthrene sorption were also studied by comparing apparent solid-water distribution coefficients (Kdapp) of phenanthrene. Two addition sequences, including “cosolute added prior to phenanthrene” and “cosolute and phenanthrene added simultaneously,” were adopted. The Freundlich model fits phenanthrene sorption on all 3 sorbents well. The sorption coefficients on these sorbents were similar, suggesting that mineral surface plays an important role in the sorption of hydrophobic organic contaminants on low OC% sediments. Cosolutes could affect phenanthrene sorption on the sorbents, which depended on their properties, concentrations, and addition sequences. Pyrene inhibited phenanthrene sorption. Sorbed NP inhibited phenanthrene sorption at low levels and promoted sorption at high levels. Similar to NP, effect of HA on phenanthrene sorption onto the natural sediment depended on its concentrations, whereas, for the organic-free sediment and kaolinite, preloading of HA at high levels led to an enhancement in phenanthrene Kdapp while no obvious effect was observed at low HA levels; dissolved HA could inhibit phenanthrene sorption on the two sorbents. PMID:25147865

  14. [Sorption and desorption of phenanthrene by organo-mineral complexes with different bridge cations].

    PubMed

    Ni, Jin-zhi; Luo, Yong-ming; Wei, Ran; Li, Xiu-hua; Qian, Wei

    2008-12-01

    Sorption and desorption of phenanthrene by organo-mineral complexes with Ca2+, Fe3+ and Al3+ as bridge cations were studied according to the association type between organic matter and minerals in natural soils. The results showed that the data of phenanthrene sorption and desorption by different cation saturated montmorillonite and their corresponding humic acid and mineral complexes could be fitted with Freundlich model, and the order of the sorption capacities (Kf) were Ca-Mont (0.184) > Fe-Mont (0.028) > Al-Mont (0.015) and Fe-Mont-HA (2.341) > Ca-Mont-HA (1.557) > Al-Mont-HA (1.136), respectively. The Kf values of humic acid and mineral complexes were far greater than those of minerals, which demonstrated that humic acid made great contributions to the sorption of phenanthrene in the organo-mineral complexes. However, the Kf values of the organo-mineral complexes with different bridge cations were not consistent with their organic carbon content, which indicated that both the organic carbon content and the combined types between organic matter and mineral could affect the sorption capacity of phenanthrene by the organo-mineral complexes. The desorption hysteresis of phenanthrene was significant for Ca2+ and Al3+ bridged organo-mineral complexes. Desorption hysteresis of phenanthrene was mainly from the sorption of phenanthrene by organic matter, and the contributions of mineral to the desorption hysteresis were not significant.

  15. Turbulent Coagulation of Particles Smaller Than the Length Scales of Turbulence and Equilibrium Sorption of Phenanthrene to Clay: Implications for Pollutant Transport in the Estuarine Water Column

    DTIC Science & Technology

    1997-05-01

    estuaries was modeled using phenanthrene, bacterial extracellular polymer and kaolinite clay as surrogates for a hydrophobic organic pollutant...coefficients obtained for phenanthrene sorption to kaolinite and bentonite in the presence of varying amounts of DOM represented by alginic acid and tannic...acid. 333 Table B.3: Literature values for sorption between phenanthrene, humic acid and kaolinite for [DOM]a = 10 mg/L 334 Table E.1: Sample output data

  16. Visible light photodegradation of phenanthrene catalyzed by Fe(III)-smectite: role of soil organic matter.

    PubMed

    Jia, Hanzhong; Li, Li; Fan, Xiaoyun; Liu, Mingdeng; Deng, Wenye; Wang, Chuanyi

    2013-07-15

    In the present study, phenanthrene is employed as a model to explore the roles played by three soil organic matter (SOM) fractions, i.e., dissolved organic matter (DOM), humic acid (HA), and fulvic acid (FA), in its photodegradation with assistance of Fe(III)-smectite under visible-light. Slight decrease in phenanthrene photodegradation rate was observed in the presence of DOM, which is explained in terms of oxidative-radical competition between DOM and target phenanthrene molecules due to the high electron-donor capacity of phenolic moieties in DOM. On the other hand, a critic content is observed with FA (0.70mg/g) and HA (0.65mg/g). Before reaching the critic content, the removal of phenanthrene is accelerated; while after that, the photodegradation rate is suppressed. The acceleration of phenanthrene degradation can be attributed to the photosensitization of FA and HA. Due to the strong interaction between phenanthrene and the phenyl rings, however, the retention of phenanthrene on SOM-Fe(III)-smectite in the presence of high content of HA or FA is enhanced, thus slowing down its photodegradation. Those observations provide valuable insights into the transformation and fate of PAHs in the natural soil environment and open a window for using clay-humic substances complexes for remediation of contaminated soil.

  17. Effects of dissolved organic matter derived from forest leaf litter on biodegradation of phenanthrene in aqueous phase.

    PubMed

    Cai, Dan; Yang, Xiuhong; Wang, Shizhong; Chao, Yuanqing; Morel, J L; Qiu, Rongliang

    2017-02-15

    Dissolved organic matter (DOM) released from forest leaf litter is potentially effective for the degradation of polycyclic aromatic hydrocarbons (PAHs), yet the inherent mechanism remains insufficiently elucidated. In this study, we investigated the effects of DOM derived from Pinus elliottii and Schima superba leaf litter on the degradation of phenanthrene by the phenanthrene degrading bacterium Sphingobium sp. Phe-1. DOM from different origins and at a large range of concentrations enhanced the degradation rate of phenanthrene. DOM derived from P. elliottii leaf litter decomposed for 12 months used at a concentration of 100mg/L yielded the highest degradation rate (16.9% in 36h) and shortened the degradation time from 48h to 24h. Changes in the composition of DOM during degradation as measured by EEMs-FRI showed that proteins and tyrosine in the DOM supplied readily available nutrients that stimulated biological activity of Phe-1, increasing its growth rate and catechol 2,3-dioxygenase activity. Simultaneously, fulvic acid and humic acid in the DOM enhanced phenanthrene bioavailability by increasing the solubility and mass transfer of phenanthrene, enhancing the uptake kinetics of Phe-1, and increasing the bacteria's direct access to DOM-associated phenanthrene. Humic acid was co-metabolized by Phe-1, resulting in further stimulation of phenanthrene degradation.

  18. Replica plating method for estimating phenanthrene-utilizing and phenanthrene-cometabolizing microorganisms

    SciTech Connect

    Shiaris, M.P.; Cooney, J.J.

    1983-02-01

    A replica plating method was developed for detecting and enumerating phenanthrene-degrading microorganisms. The method is designed to discriminate between aquatic organisms that utilize phenanthrene as the sole carbon and energy source and organisms that cometabolize phenanthrene. The method was used to demonstrate that phenanthrene utilizers and phenanthrene cometabolizers coexist in estuarine sediments.

  19. Vegetative bioremediation of phenanthrene

    SciTech Connect

    Malathi, A.; Banks, M.K.; Schwab, A.P.

    1994-12-31

    The role of vegetation to stimulate the degradation and detoxification of toxic and recalcitrant organic chemicals at low soil concentrations is brought about by several mechanisms of plant-soil interactions, including improvement of physical and chemical properties of contaminated soils, increase in soil microbial activity and increase in contact between microbes associated with the roots and toxic compounds in a contaminated soil. This represents a potential cost effective and low maintenance alternative for waste management. However, there is not enough information concerning specific application of plants, chemicals and soils either in the form of laboratory or field results. In the research to be presented, different and diverse perennial plant species [grasses (monocot), legumes, and dicots] were collected from the native prairie grasslands and tested for their efficiency in mineralization of phenanthrene. The mineralization of phenanthrene was evaluated by the measurement of {sup 14}CO{sub 2} from the radiolabeled target compound incubated in a rhizosphere soil microcosm. Results from this study will indicate the potential of using different types of plants to enhance degradation of PAHs in contaminated soils.

  20. Stepwise adsorption of phenanthrene at the fly ash-water interface as affected by solution chemistry: experimental and modeling studies.

    PubMed

    An, Chunjiang; Huang, Guohe

    2012-11-20

    Fly ash (FA) is predominantly generated from coal-fired power plants. Contamination during disposal of FA can cause significant environmental problems. Knowledge about the interaction of FA and hydrophobic organic pollutants in the environment is very limited. This study investigated the adsorption of phenanthrene at the interface of FA and water. The performance of phenanthrene adsorption on FA and the effects of various aqueous chemistry conditions were evaluated. The adsorption isotherms exhibited an increasing trend in the adsorbed amounts of phenanthrene, while a stepwise pattern was apparent. A stepwise multisite Langmuir model was developed to simulate the stepwise adsorption process. The adsorption of phenanthrene onto FA was noted to be spontaneous at all temperatures. The thermodynamic results indicated that the adsorption was an exothermic process. The adsorption capacity gradually decreased as pH increased from 4 to 8; however, this trend became less significant when pH was changed from 8 to 10. The binding affinity of phenanthrene to FA increased after the addition of humic acid (HA). The pH variation was also responsible for the changes of phenanthrene adsorption on FA in the presence of HA. High ionic strength corresponded to low mobility of phenanthrene in the FA-water system. Results of this study can help reveal the migration patterns of organic contaminants in the FA-water system and facilitate environmental risk assessment at FA disposal sites.

  1. [Adsorption of aflatoxin on montmorillonite modified by low-molecular-weight humic acids].

    PubMed

    Yao, Jia-Jia; Kang, Fu-Xing; Gao, Yan-Zheng

    2012-03-01

    The adsorption of a typical biogenic toxin aflatoxin B1 on montmorillonite modified by low-molecular-weight humic acids (M(r) < 3 500) was investigated. The montmorillonite rapidly adsorbed the aflatoxin B1 until amounting to the maximal capacity, and then the adsorbed aflatoxin B1 slowly released into solution and reached the sorption equilibrium state after 12 h. The sorption isotherm of aflatoxin B1 by montmorillonite could be well described by Langmiur model, while the sorption isotherm by humic acid-modified montmorillonite was well fitted by using the Freundlich model. The modification of the montmorillonite with humic acids obviously enhanced its adsorption capacity for aflatoxin B1, and the amounts of aflatoxin adsorbed by modified montmorillonite were obviously higher than those by montmorillonite. The sorption enhancement by humic acid modification was attributed to (1) the enlarged adsorption sites which owed to the surface collapse of crystal layers induced by organic acids, and (2) the binding of aflatoxin with the humic acid sorbed on mineral surface. In addition, the adsorption amounts of aflatoxin by montmorillonite and modified montmorillonite increased with the increase of pH values in solution, and more significant enhancement was observed for the latter than the former, which attributed to the release of humic acids from the modified montmorillonite with the high pH values in solution. This indicates that increasing the pH values resulted in the enhanced hydrophilic property and the release of the organic acids presented in modified montmorillonite, and more sorption sites were available for aflatoxin on the modified montmorillonite. Results of this work would strengthen our understanding of the behavior and fate of biological contaminants in the environment.

  2. Ba2phenanthrene is the main component in the Ba-doped phenanthrene superconductor

    NASA Astrophysics Data System (ADS)

    Yan, Xun-Wang; Huang, Zhongbing; Lin, Hai-Qing

    2014-12-01

    We have systematically investigated the crystal structure of Ba-doped phenanthrene with various Ba doping levels by the first-principles calculations combined with the X-ray diffraction (XRD) spectra simulations. Although the experimental stoichiometry ratio of Ba atom and phenanthrene molecule is 1.5:1, the simulated XRD spectra, space group symmetry and optimized lattice parameters of Ba1.5phenanthrene are not consistent with the experimental ones, while the results for Ba2phenanthrene are in good agreement with the measurements. The strength difference of a few XRD peaks can be explained by the existence of pristine phenanthrene. Our findings suggest that instead of uniform Ba1.5phenanthrene, there coexist Ba2phenanthrene and undoped phenanthrene in the superconducting sample. The electronic calculations indicate that Ba2phenanthrene is a semiconductor with a small energy gap less than 0.05 eV.

  3. Ba{sub 2}phenanthrene is the main component in the Ba-doped phenanthrene superconductor

    SciTech Connect

    Yan, Xun-Wang; Huang, Zhongbing; Lin, Hai-Qing

    2014-12-14

    We have systematically investigated the crystal structure of Ba-doped phenanthrene with various Ba doping levels by the first-principles calculations combined with the X-ray diffraction (XRD) spectra simulations. Although the experimental stoichiometry ratio of Ba atom and phenanthrene molecule is 1.5:1, the simulated XRD spectra, space group symmetry and optimized lattice parameters of Ba{sub 1.5}phenanthrene are not consistent with the experimental ones, while the results for Ba{sub 2}phenanthrene are in good agreement with the measurements. The strength difference of a few XRD peaks can be explained by the existence of pristine phenanthrene. Our findings suggest that instead of uniform Ba{sub 1.5}phenanthrene, there coexist Ba{sub 2}phenanthrene and undoped phenanthrene in the superconducting sample. The electronic calculations indicate that Ba{sub 2}phenanthrene is a semiconductor with a small energy gap less than 0.05 eV.

  4. Correlation between biological and physical availabilities of phenanthrene in soils and soil humin in aging experiments

    SciTech Connect

    White, J.C.; Hunter, M.; Nam, K.; Pignatello, J.J.; Alexander, M.

    1999-08-01

    The bioavailability of an organic compound in a soil or sediment commonly declines with the soil-chemical contact time (aging). A series of parallel desorption and bioavailability experiments was carried out on phenanthrene previously aged up to {approximately}100 d in Mount Pleasant silt loam (Mt. Pleasant, NY, USA) or Pahokee peat soil to determine as a function of the aging period the degree of correlation between the reduction in bioavailability and the rate and extent of desorption and the influence of soil organic matter composition on availability. The mineralization of phenanthrene by two bacteria and the uptake of phenanthrene by earthworms showed expected declines with aging. Likewise, the rate of phenanthrene desorption in the absence of organisms decreased with aging. The decline in initial rate of mineralization or desorption was nearly an order of magnitude after 50 to 60 d of aging. Plots of normalized rates of mineralization or desorption practically coincided. Similarly, plots of normalized fraction mineralized or fraction desorbed during an arbitrary period gave comparable slopes. The partial removal of organic matter from the peat by extraction with dilute NaOH to leave the humin fraction reduced the biodegradation of phenanthrene aged for 38 and 63 d as compared to the nonextracted peat, but the effect disappeared at longer incubation times. The rate of desorption from samples of peat previously extracted with NaOH or Na{sub 4}P{sub 2}O{sub 7} declined with aging and, for a given aging period, was significantly slower than from nonextracted peat. This work shows that the reduction in bioavailability of phenanthrene over time in soil is directly correlated with reduction of its physical availability due to desorption limitations. In addition, this study shows that removal of extractable humic substances leads to a decline in the rate of desorption and in the bioavailability of the substrate.

  5. Toxic photoproducts of phenanthrene in sunlight

    SciTech Connect

    McConkey, B.L.; Duxbury, C.L.; El-Alawi, Y.S.; Dixon, D.G.; Greenberg, B.M.

    1995-12-31

    Phenanthrene, one of the most prevalent PAHs, undergoes a significant increase in toxicity on exposure to sunlight. Over a period of several days exposure to light, the toxicity of an aqueous phenanthrene solution increased dramatically. This increase in toxicity is largely due to the primary photoproduct, 9,10-phenanthrenequinone. This compound is more toxic than phenanthrene at equimolar concentrations, and is more water soluble than phenanthrene, increasing its bioavailability. Although many PAHs are potent photosensitizers, phenanthrene did not exhibit a significant increase in toxicity due to photosensitization. Photo-oxidation was the principal cause of photoinduced toxicity, with 9,10-phenanthrenequinone being formed via an unstable intermediate. In addition, mixtures of phenanthrene and 9,10-phenanthrenequinone exhibited potentially synergistic effects, as shown by joint toxicity testing using Photobacterium phosphoreum. Thus, mixtures of oxidized PAHs produced by photoaction in the environment create a significant risk to the biosphere.

  6. Metabolism of phenanthrene by Phanerochaete chrysosporium

    SciTech Connect

    Sutherland, J.B.; Selby, A.L.; Freeman, J.P.; Evans, F.E.; Cerniglia, C.E. )

    1991-11-01

    The white rot fungus Phanerochaete chyrsosporium metabolized phenanthrene when it was grown for 7 days at 37C in a medium containing malt extract, D-glucose, D-maltose, yeast extract, and Tween 80. After cultures were grown with (9-{sup 14}C)phenanthrene, radioactive metabolites were extracted from the medium with ethyl acetate, separated by high-performance liquid chromatography, and detected by liquid scintillation counting. Metabolites from cultures grown with unlabeled phenanthrene were identified as phenanthrene trans-9, 10-dihydrodiol, phenanthrene trans-3, 4-dihydrodiol, 9-phenanthrol, 3-phenanthrol, 4-phenanthrol, and the novel conjugate 9-phenanthryl {beta}-D-glucopyranoside. Identification of the compounds was based on their UV absorption, mass, and nuclear magnetic resonance spectra. Since lignin peroxidase was not detected in the culture medium, these results suggest the involvement of monooxygenase and epoxide hydrolase activity in the initial oxidation and hydration of phenanthrene by P. chrysosporium.

  7. Mineralization of phenanthrene by a Mycobacterium sp

    SciTech Connect

    Guerin, W.F.; Jones, G.E.

    1988-04-01

    A Mycobacterium sp., designated strain BG1, able to utilize the polycyclic aromatic hydrocarbon phenanthrene as the sole carbon and energy source was isolated from estuarine sediment following enrichment with the hydrocarbon. Unlike other phenanthrene degraders, this bacterium degraded phenanthrene via 1-hydroxy-2-naphthoic acid without accumulating this or other aromatic intermediates, as shown by high-performance liquid chromatography. Degradation proceeded via meta cleavage of protocatechuic acid. Different nonionic surfactants (Tween compounds) solubilized the phenanthrene to different degrees and enhanced phenanthrene utilization. The order of enhancement, however, did not correlate perfectly with increased solubility, suggesting physiological as well as physicochemical effects of the surfactants. Plasmids of approximately 21, 58, and 77 megadaltons were detected in cells grown with phenanthrene but not in those which, after growth on nutrient media, lost the phenanthrene-degrading phenotype. Given that plasmid-mediated degradations of aromatic hydrocarbons generally occur via meta cleavages, it is of interest that the addition of pyruvate, a product of meta cleavage, supported rapid mineralization of phenanthrene in broth culture; succinate, a product of ortho cleavage, supported growth but completely repressed the utilization of phenanthrene. The involvement of plasmids may have given rise to the unusual degradation pattern that was observed.

  8. Spectroscopic characterization of dissolved organic matter isolates from sediments and the association with phenanthrene binding affinity.

    PubMed

    Hur, Jin; Lee, Bo-Mi; Shin, Kyung-Hoon

    2014-09-01

    In this study, selected spectroscopic characteristics of sediment organic matter (SOM) were compared and discussed with respect to their different isolation methods, the source discrimination capabilities, and the association with the extent of phenanthrene binding. A total of 16 sediments were collected from three categorized locations including a costal lake, industrial areas, and upper streams, each of which is likely influenced by the organic sources of algal production, industrial effluent, and terrestrial input, respectively. The spectroscopic properties related to aromatic structures and terrestrial humic acids were more pronounced for alkaline extractable organic matter (AEOM) isolates than for the SOM isolates based on water soluble extracts and pore water. The three categorized sampling locations were the most differentiated in the AEOM isolates, suggesting AEOM may be the most representative SOM isolates in terms of describing the chemical properties and the organic sources of SOM. Parallel factor analysis (PARAFAC) based on fluorescence excitation-emission matrix (EEM) showed that a combination of three fluorescent groups could represent all the fluorescence features of SOM. The three categorized sampling locations were well discriminated by the percent distributions of humic-like fluorescent groups of the AEOM isolates. The relative distribution of terrestrial humic-like fluorophores was well correlated with the extent of phenanthrene binding (r=0.571; p<0.05), suggesting that the presence of humic acids in SOM may contribute to the enhancement of binding with hydrophobic organic contaminants in sediments. Principal component analysis (PCA) further demonstrated that the extent of SOM's binding affinity might be affected by the degree of biogeochemical transformation in SOM.

  9. The effect of humic acids on biodegradation of polycyclic aromatic hydrocarbons depends on the exposure regime.

    PubMed

    Tejeda-Agredano, Maria-Carmen; Mayer, Philipp; Ortega-Calvo, Jose-Julio

    2014-01-01

    Binding of polycyclic aromatic hydrocarbons (PAHs) to dissolved organic matter (DOM) can reduce the freely dissolved concentration, increase apparent solubility or enhance diffusive mass transfer. To study the effects of DOM on biodegradation, we used phenanthrene and pyrene as model PAHs, soil humic acids as model DOM and a soil Mycobacterium strain as a representative degrader organism. Humic acids enhanced the biodegradation of pyrene when present as solid crystals but not when initially dissolved or provided by partitioning from a polymer. Synchronous fluorescence spectrophotometry, scintillation counting and a microscale diffusion technique were applied in order to determine the kinetics of dissolution and diffusive mass transfer of pyrene. We suggest that humic acids can enhance or inhibit biodegradation as a result of the balance of two opposite effects, namely, solubilization of the chemicals on the one hand and inhibition of cell adhesion to the pollutant source on the other.

  10. Estuarine ecology of phenanthrene-degrading bacteria

    NASA Astrophysics Data System (ADS)

    Guerin, William F.; Jones, Galen E.

    1989-08-01

    Phenanthrene degrading bacteria were ubiquitously distributed in waters and sediments of the Great Bay Estuary, NH, as determined using a 14C-phenanthrene mineralization assay. Similar activities were observed in water samples collected in March and June when these were incubated at 18 °C even though ambient water temperatures were 1-4 °C and 10-22 °C, respectively. This observation indicated the constant presence of a mesophilic phenanthrene-degrading bacterial population in the estuary. Among water samples, the highest biodegradation activities were associated with samples collected downstream from a dredging operation which introduced high concentrations of coal tar PAH (polycyclic aromatic hydrocarbons) into the Cocheco River, and in areas receiving PAH from pleasure and commercial boating activities. Mid-estuarine maxima in biodegradation activity during both sampling trips suggested adaptation of the microbial flora to the salinities prevailing in the low turnover, high residence time portion of the Estuary at the time of sampling. Despite the hydrophobicity of phenanthrene, no correlation between biodegradation rates and particulate matter concentrations were observed. Similarly, concentrations of nutrients and dissolved and particulate organic matter correlated poorly with biodegradation rates. Better agreements between 14C-phenanthrene mineralization potentials and plate counts on a phenanthrene/toluene agar (PTA) medium were observed. Phenanthrene biodegradative activities and numbers of culturable bacteria growing on PTA were governed by the degree of previous exposure to PAH.

  11. Comparative embryotoxicity of phenanthrene and alkyl-phenanthrene to marine medaka (Oryzias melastigma).

    PubMed

    Mu, Jingli; Wang, Juying; Jin, Fei; Wang, Xinhong; Hong, Huasheng

    2014-08-30

    Alkylated polycyclic aromatic hydrocarbons (alkyl-PAHs) are the predominant form of PAHs in oil, comprising 85-95% of total PAHs. However, little attention has been paid to these chemicals in ecological risk assessment of marine oil spill. A comparative study of the toxic effects of phenanthrene and retene (7-isopropyl-1-methylphenanthrene, an alkyl-phenanthrene) on the early life stage of marine medaka (Oryzias melastigma) was conducted. Results showed that retene was significantly more toxic than phenanthrene, and marine medaka could be more sensitive to retene than some freshwater fishes. Retene had a higher excretion rate than phenanthrene during the larvae stage. Both of compounds resulted in developmental malformation of marine medaka embryos, with phenanthrene affecting on peripheral vascular system and yolk sac, while retene affecting on cardiac tissues. The toxicity of phenanthrene might be mainly related to its anesthetic effects, and that of retene might be related to the CYP1A-mediated toxicity of its metabolites.

  12. Temperature-dependent conformational variation of chromophoric dissolved organic matter and its consequent interaction with phenanthrene.

    PubMed

    Chen, Wei; Liu, Xiao-Yang; Yu, Han-Qing

    2017-03-01

    Temperature variation caused by climate change, seasonal variation and geographic locations affects the physicochemical compositions of chromophoric dissolved organic matter (CDOM), resulting in difference in the fates of CDOM-related environmental pollutants. Exploration into the thermal induced structural transition of CDOM can help to better understand their environmental impacts, but information on this aspect is still lacking. Through integrating fluorescence excitation-emission matrix coupled parallel factor analysis with synchronous fluorescence two-dimensional correlation spectroscopy, this study provides an in-depth insight into the temperature-dependent conformational transitions of CDOM and their impact on its hydrophobic interaction with persistent organic pollutants (with phenanthrene as an example) in water. The fluorescence components in CDOM change linearly to water temperature with different extents and different temperature regions. The thermal induced transition priority in CDOM is protein-like component → fulvic-like component → humic-like component. Furthermore, the impact of thermal-induced conformational transition of CDOM on its hydrophobic interaction with phenanthrene is observed and explored. The fluorescence-based analytic results reveal that the conjugation degree of the aromatic groups in the fulvic- and humic-like substances, and the unfolding of the secondary structure in the protein-like substances with aromatic structure, contribute to the conformation variation. This integrated approach jointly enhances the characterization of temperature-dependent conformational variation of CDOM, and provides a promising way to elucidate the environmental behaviours of CDOM.

  13. Biodegradation kinetics of phenanthrene solubilized in surfactant micelles

    SciTech Connect

    Grimberg, S.J.; Aitken, M.D.

    1995-12-31

    The biodegradation of phenanthrene solubilized in surfactant micelles was studied using a simple, well-defined laboratory system. The system was designed to evaluate whether phenanthrene present in micelles of the nonionic surfactant Tergitol NP-10 was available to a phenanthrene-degrading bacterium. Results indicate that micellized phenanthrene is essentially unavailable to the microorganism, so that only the phenanthrene present in the aqueous phase is degraded. A modified Michaelis-Menten equation was developed to quantify the effects of surfactant concentration on phenanthrene uptake rates. Experimental data were described well with this equation.

  14. The Halophyte Cakile maritima Reduces Phenanthrene Phytotoxicity.

    PubMed

    Shiri, Moez; Rabhi, Mokded; El Amrani, Abdelhak; Abdelly, Chedly

    2015-01-01

    In a previous study, we showed that the halophyte plant model Thellungiella salsuginea was more tolerant to phenanthrene (Polycyclic Aromatic Hydrocarbon: PAH) than its relative glycophyte Arabidopsis thaliana. In the present work, we investigated the potential of another halophyte with higher biomass production, Cakile maritma, to reduce phenanthrene phytotoxicity. Sand was used instead of arable soil with the aim to avoid pollutant degradation by microorganisms or their interaction with the plant. After 6 weeks of treatment by 500 ppm phenanthrene (Phe), stressed plants showed a severe reduction (-73%) in their whole biomass, roots being more affected than leaves and stems. In parallel, Guaiacol peroxidase (GPX) activity was increased by 185 and 62% in leaves and roots, respectively. Non-enzymatic antioxidant capacity (assayed by ABTS test) was maintained unchanged in all plant organs. The model halophytic plant Thellungiella salsuginea was used as a biomarker of phenanthrene stress severity and was grown at 0 (control), 125, 250, and 375 ppm. T. salsuginea plants grown on the sand previously contaminated by 500 ppm Phe then treated by C. maritma culture (phytoremediation culture) showed similar biomass production as plants subjected to 125 ppm Phe. This suggests that the phytotoxic effects of phenanthrene were reduced by 75% by the 6-week treatment by C. maritima. Our findings indicate that C. maritima can constitute a potentially good candidate for PAH phytoremediation.

  15. Adsorption of phenanthrene on natural snow.

    PubMed

    Domine, Florent; Cincinelli, Alessandra; Bonnaud, Elodie; Martellini, Tania; Picaud, Sylvain

    2007-09-01

    The snowpack is a reservoir for semivolatile organic compounds (SVOCs) and, in particular, for persistent organic pollutants (POPs), which are sequestered in winter and released to the atmosphere or hydrosphere in the spring. Modeling these processes usually assumes that SVOCs are incorporated into the snowpack by adsorption to snow surfaces, but this has never been proven because the specific surface area (SSA) of snow has never been measured together with snow composition. Here we expose natural snow to phenanthrene vapors (one of the more volatile POPs) and measure for the first time both the SSA and the chemical composition of the snow. The results are consistent with an adsorption equilibrium. The measured Henry's law constant is H(Phen)(T) = 2.88 x 10(22) exp(-10660/7) Pa m2 mol(-1), with Tin Kelvin. The adsorption enthalpy is delta H(ads) = -89 +/- 18 kJ mol(-1). We also perform molecular dynamics calculations of phenanthrene adsorption to ice and obtain AHads = -85 +/- 8 kJ mol(-1), close to the experimental value. Results are applied to the adsorption of phenanthrene to the Arctic and subarctic snowpacks. The subarctic snowpack, with a low snow area index (SAI = 1000), is a negligible reservoir of phenanthrene, butthe colder Arctic snowpack, with SAI = 2500, sequesters most of the phenanthrene present in the (snow + boundary layer) system.

  16. Degradation of phenanthrene on plant leaves by phyllosphere bacteria.

    PubMed

    Waight, Karen; Pinyakong, Onruthai; Luepromchai, Ekawan

    2007-10-01

    The activity of phyllosphere bacteria in the degradation of phenanthrene was investigated as a mechanism for the removal of atmospheric phenanthrene after its deposition on plant leaves. Initially, leaf samples of six plant species were collected from two roadsides in Bangkok to determine the presence of phenanthrene-degrading bacteria. The numbers of phenanthrene-degrading phyllosphere bacteria were varied and ranged from 3.5 x 10(4) to 1.95 x 10(7) CFU/g, in which the highest number was found from Ixora sp. Further studies were carried out in the laboratory by spraying phenanthrene on Ixora sp. leaves and then monitoring the amount of deposited phenanthrene and number of phenanthrene-degrading bacteria after incubation. The results showed that the amount of phenanthrene was significantly reduced on leaves containing phenanthrene-degrading bacteria. These were detected along with a rapid increase in the number of bacteria on leaves. The results indicated that many phyllosphere bacteria could utilize phenanthrene to support their growth and thereby reduce the amount of deposited phenanthrene on leaf surfaces. Several phenanthrene-degrading bacteria were later isolated from the leaves and identified with a high 16S rDNA sequence similarity to the genera Pseudomonas, Microbacterium, Rhizobium, and Deinococcus.

  17. Oxidative degradation of phenanthrene by the ligninolytic fungus phanerochaete chrysosposium

    SciTech Connect

    Hammel, K.E.; Gai, W.Z.; Green, B.; Moen, M.A.

    1992-01-01

    The ligninolytic fungus Phanerochaete chrysosporium oxidized phenanthrene and phenanthrene-9,10-quinone (PQ) at their C-9 and C-10 positions to give a ring-fission product, 2,2'-diphenic acid (DPA), which was identified in chromatographic and isotope dilution experiments. DPA formation from phenanthrene was somewhat greater in low-nitrogen (ligninolytic) cultures than in high-nitrogen (nonligninolytic) cultures and did not occur in uninoculated cultures. The oxidation of PQ to DPA involved both fungal and abiotic mechanisms, was unaffected by the level of nitrogen added, and was significantly faster than the cleavage of phenanthrene to DPA. Phenanthrene-trans-9,10-dihydrodiol, which was previously shown to be the principal phenanthrene metabolite in nonligninolytic P. chrysosporium cultures, was not formed in the ligninolytic cultures employed here. These results suggest that phenanthrene degradation by ligninolytic P. chrysosporium proceeds in order from phenanthrene -> PQ -> DPA, involves both ligninolytic and nonligninolytic enzymes, and is not initiated by a classical microsomal cytochrome P-450. The extracellular lignin peroxidases of P. chrysosporium were not able to oxidize phenanthrene in vitro and therefore are also unlikely to catalyze the first step of phenanthrene degradation in vivo. Both phenanthrene and PQ were mineralized to similar extents by the fungus, which supports the intermediacy of PQ in phenanthrene degradation, but both compounds were mineralized significantly less than the structurally related lignin peroxidase substrate pyrene was.

  18. Oxidative degradation of phenanthrene by the ligininolytic fungus Phanerochaete chrysosporium

    SciTech Connect

    Hammel, K.E.; Moen, M.A. ); Wen Zhigai; Green, B. )

    1992-06-01

    The ligninolytic fungus Phanerochaete chrysosporium oxidized phenanthrene and phenanthrene-9,10-quinone (PQ) at their C-9 and C-10 positions to give a ring-fission product, 2,2[prime]-diphenic acid (DPA), which was identified in chromatographic and isotope dilution experiments. DPA formation from phenanthrene was somewhat greater in low-nitrogen cultures than in high-nitrogen cultures and did not occur in uninoculated cultures. The oxidation of PQ to DPA involved both fungal and abiotic mechanisms, was unaffected by the level of nitrogen added, and was significantly faster than the cleavage of phenanthrene to DPA. Phenanthrene-trans-9,10-dihydrodiol, which was previously shown to be the principal phenathrene metabolite in nonligninolytic P. chrysosporium cultures, was not formed in the ligninolytic cultures employed here. These results suggest that phenanthrene degradation by ligninolytic P. chrysosporium proceeds in order from phenanthrene [yields] PQ [yields] DPA, involves both ligninolytic and nonligninolytic enzymes, and is not initiated by a classical microsomal cytochrome P-450. The extracellular lignin peroxidases of P. chrysosporium were not able to oxidize phenanthrene in vitro and therefore are also unlikely to catalyze the first step of phenanthrene degradation in vivo. Both phenanthrene and PQ were mineralized to similar extents by the fungus, which supports the intermediacy of PQ in phenanthrene degradation, but both compounds were mineralized significantly less than the structurally related lignin peroxidase substrate pyrene was.

  19. Microbial degradation of dissolved organic matter (DOM) and its influence on phenanthrene-DOM interactions.

    PubMed

    Hur, Jin; Lee, Bo-Mi; Shin, Hyun-Sang

    2011-11-01

    Microbial degradation-induced changes in the characteristics of dissolved organic matter (DOM), and the subsequent effects on phenanthrene-DOM interactions were investigated based on the microbial incubation of DOM collected from four different sources for 28 d. Partially biodegraded DOM presented higher specific UV absorbance (SUVA), lower protein-like fluorescence, higher humic-like fluorescence, lower aliphatic carbon fraction, and higher hydrophobic neutral fractions compared to the original DOM. Microbial changes in DOM led to an increase in the isotherm nonlinearity as well as the extent of phenanthrene binding. A negative relationship between SUVA and the Freundlich n values was established for the original and the biodegraded DOM, suggesting that aromatic condensed structures may play important roles in providing nonlinear strong binding sites irrespective of microbial degradation. In contrast, there were two separate slopes of the correlations between the percentage of hydrophobic acid (HoA) fraction and the n values for the original and the biodegraded DOM with a higher slope exhibited for the latter, implying that the microbial utilization of oxygen-containing structures in the HoA fractions may contribute to enhancing the associated isotherm nonlinearity.

  20. Enhanced transport of phenanthrene and 1-naphthol by colloidal graphene oxide nanoparticles in saturated soil.

    PubMed

    Qi, Zhichong; Hou, Lei; Zhu, Dongqiang; Ji, Rong; Chen, Wei

    2014-09-02

    With the increasing production and use of graphene oxide, the environmental implications of this new carbonaceous nanomaterial have received much attention. In this study, we found that the presence of low concentrations of graphene oxide nanoparticles (GONPs) significantly enhanced the transport of 1-naphthol in a saturated soil, but affected the transport of phenanthrene to a much smaller extent. The much stronger transport-enhancement effect on 1-naphthol was due to the significant desorption hysteresis (both thermodynamically irreversible adsorption and slow desorption kinetics) of GONP-adsorbed 1-naphthol, likely stemmed from the specific polar interactions (e.g., H-bonding) between 1-naphthol and GONPs. Increasing ionic strength or the presence of Cu(II) ion (a complexing cation) generally increased the transport-enhancement capability of GONPs, mainly by increasing the aggregation of GONPs and thus, sequestering adsorbed contaminant molecules. Interestingly, modifying GONPs with Suwannee River humic acid or sodium dodecyl sulfate had little or essentially no effect on the transport-enhancement capability of GONPs, in contrast with the previously reported profound effects of humic acids and surfactants on the transport-enhancement capability of C60 nanoparticles. Overall, the findings indicate that GONPs in the aquatic environment may serve as an effective carrier for certain organic compounds that can interact with GONPs through strong polar interactions.

  1. Phenanthrene biodegradation kinetics in unsaturated soils

    SciTech Connect

    Johnson, C.R.; Scow, K.M.

    1995-12-31

    Organic compounds when sorbed to soil solids are thought to be unavailable to soil microorganisms. The biodegradation kinetics of sorbed chemicals should thus be influenced by sorption/desorption processes as well as by the metabolic capacities of soil microbes. In the research, phenanthrene, a hydrophobic polyaromatic hydrocarbon, was used as a model compound to investigate the biodegradation kinetics of strongly sorbing organic compounds in soil. Biodegradation kinetics for phenanthrene in seven soils with moisture contents near field capacity were measured during a six and one half month experiment. Phenanthrene biodegradation rates initially increased in all soils and then declined. The declining portion of the biodegradation rate versus time plots exhibited either first order or biphasic kinetics. Both first order and biphasic kinetics are consistent with models which link microbial degradation to substrate sorption/desorption from equilibrium and kinetically controlled sorption sites. No single rate constant or analytical expression adequately captured the complexity of the observed biodegradation rates. This result is again consonant with a process derived from coupled biological and physical systems. Biodegradation kinetics were quantified using a combination of fitted and descriptive parameters. Significant correlations exist between several of the descriptive parameters. The correlations observed between descriptive biodegradation parameters mirror correlations expected from the hypothesized underlying biological process and help evince the influence this underlying process exerts on observed biodegradation kinetics.

  2. Interaction of polycyclic aromatic hydrocarbons with a soil humic acid in aqueous solution

    SciTech Connect

    Jones, K.D.; Tiller, C.L.

    1996-10-01

    The effects of pH, ionic strength, and cation type on the interactions of several polycyclic aromatic hydrocarbons (PAHs) with a well-characterized soil humic acid were investigated. Binding coefficients (K{sub oc}) for anthracene, phenanthrene, pyrene, and triphenylene were determined by fluorescence quenching. At low ionic strength (as NaNO{sub 3}), K{sub oc}, for each of the PAHs increased with pH in the range 4 to 10; at high ionic strength this trend was less apparent. At a given pH, the effect of ionic strength was small, but K{sub oc} was highest at the lowest ionic strength. When pH and ionic strength were held constant but different electrolytes were used, binding of phenanthrene by the humic acid was greatest in the presence of (monovalent) sodium, followed by (bivalent) calcium, and lowest in the presence of (trivalent) aluminum. The results of this investigation are consistent with the view that interactions of hydrophobic organic compounds with natural organic matter (NOM) can be dependent on the conformational behavior of the NOM.

  3. Structural origin for electron affinity of phenanthrene and ion cores of phenanthrene anion clusters

    NASA Astrophysics Data System (ADS)

    Lee, Sang Hak; Song, Jae Kyu; Kim, Seong Keun

    2015-04-01

    We studied anion clusters of phenanthrene using photoelectron spectra and theoretical calculations. The electron affinity of phenanthrene, which lies between those of naphthalene and anthracene, was explained by the orbital interaction model that reflected the structural differences among these molecules. The spectral feature of the photoelectron spectra indicated strong electron-vibration coupling along two symmetric vibrational modes. Since the spectral features of each ion core structure were uniquely characteristic, we could identify that the pentamer anion had coexisting monomeric and trimeric cores on the basis of the shape of the photoelectron spectra and the size-dependent evolution of the electron affinity.

  4. An Undergraduate Laboratory Project Involving Photocyclizations in Independent Syntheses of Novel Chrysenes and Phenanthrenes.

    ERIC Educational Resources Information Center

    Letcher, R. M.

    1981-01-01

    Describes a project and experimental procedures, suitable for a final year organic chemistry course, in which students synthesize a variety of substituted phenanthrenes, chrysenes, and benzo phenanthrenes. (SK)

  5. Biodegradation of phenanthrene in soils in the presence of surfactants

    SciTech Connect

    Jahan, K.

    1993-01-01

    This research addresses the effect of low surfactant concentrations on the biodegradation of slightly soluble organic compounds in the presence and absence of soil. Biodegradation of phenanthrene in excess of its aqueous solubility by an acclimated mixed culture was studied in the presence of nonionic surfactants. Nonionic surfactants were selected over other types of surfactants because of their higher hydrocarbon solubilizing power, weaker adsorption to charged sites, less toxicity to bacteria, and poor foaming properties. Surfactants were tested to measure their effectiveness for increasing the solubility of phenanthrene, their adsorption on the soil matrix, their biodegradability, their effect on the adsorption of phenanthrene and on the rates of biodegradation of phenanthrene. Solubility enhancement studies of phenanthrene by the surfactants indicated relatively small effects at sub-micellar surfactant concentrations. Batch biodegradation studies in which phenanthrene was available as particulates and as a surface coating on sand were carried out in closed BOD bottles in the Hach manometric system. Addition of surfactants at 25 mg/L enhanced biodegradation rates as measured by oxygen uptake, protein production and disappearance of phenanthrene. A dynamic model which couples dissolution and biodegradation processes could adequately represent the experimental batch data. Modelling studies suggest that biodegradation was accelerated because the dissolution rates of phenanthrene increased in presence of the surfactants. Continuous flow column studies with phenanthrene coated Jordan sand was carried out to simulate groundwater flow conditions. Sorption studies on Jordan aquifer sand indicated that this low-carbon aquifer material adsorbs small amounts of phenanthrene as well as surfactants. The tests show that low surfactant concentrations were marginally beneficial in washing phenanthrene from precoated sand.

  6. Thermodynamic study of (anthracene + phenanthrene) solid state mixtures.

    PubMed

    Rice, James W; Fu, Jinxia; Sandström, Emma; Ditto, Jenna C; Suuberg, Eric M

    2015-11-01

    Polycyclic aromatic hydrocarbons (PAH) are common components of many materials, such as petroleum and various types of tars. They are generally present in mixtures, occurring both naturally and as byproducts of fuel processing operations. It is important to understand the thermodynamic properties of such mixtures in order to understand better and predict their behavior (i.e., fate and transport) in the environment and in industrial operations. To characterize better the thermodynamic behavior of PAH mixtures, the phase behavior of a binary (anthracene + phenanthrene) system was studied by differential scanning calorimetry, X-ray diffraction, and the Knudsen effusion technique. Mixtures of (anthracene + phenanthrene) exhibit non-ideal mixture behavior. They form a lower-melting, phenanthrene-rich phase with an initial melting temperature of 372 K (identical to the melting temperature of pure phenanthrene) and a vapor pressure of roughly lnP/Pa = -2.38. The phenanthrene-rich phase coexists with an anthracene-rich phase when the mole fraction of phenanthrene (xP) in the mixture is less than or equal to 0.80. Mixtures initially at xP = 0.90 consist entirely of the phenanthrene-rich phase and sublime at nearly constant vapor pressure and composition, consistent with azeotrope-like behavior. Quasi-azeotropy was also observed for very high-content anthracene mixtures (2.5 < xP < 5) indicating that anthracene may accommodate very low levels of phenanthrene in its crystal structure.

  7. Thermodynamic study of (anthracene + phenanthrene) solid state mixtures

    PubMed Central

    Rice, James W.; Fu, Jinxia; Sandström, Emma; Ditto, Jenna C.; Suuberg, Eric M.

    2015-01-01

    Polycyclic aromatic hydrocarbons (PAH) are common components of many materials, such as petroleum and various types of tars. They are generally present in mixtures, occurring both naturally and as byproducts of fuel processing operations. It is important to understand the thermodynamic properties of such mixtures in order to understand better and predict their behavior (i.e., fate and transport) in the environment and in industrial operations. To characterize better the thermodynamic behavior of PAH mixtures, the phase behavior of a binary (anthracene + phenanthrene) system was studied by differential scanning calorimetry, X-ray diffraction, and the Knudsen effusion technique. Mixtures of (anthracene + phenanthrene) exhibit non-ideal mixture behavior. They form a lower-melting, phenanthrene-rich phase with an initial melting temperature of 372 K (identical to the melting temperature of pure phenanthrene) and a vapor pressure of roughly lnP/Pa = −2.38. The phenanthrene-rich phase coexists with an anthracene-rich phase when the mole fraction of phenanthrene (xP) in the mixture is less than or equal to 0.80. Mixtures initially at xP = 0.90 consist entirely of the phenanthrene-rich phase and sublime at nearly constant vapor pressure and composition, consistent with azeotrope-like behavior. Quasi-azeotropy was also observed for very high-content anthracene mixtures (2.5 < xP < 5) indicating that anthracene may accommodate very low levels of phenanthrene in its crystal structure. PMID:26973354

  8. Biodegradation of phenanthrene and analysis of degrading cultures in the presence of a model organo-mineral matrix and of a simulated NAPL phase.

    PubMed

    Cavalca, Lucia; Rao, Maria A; Bernasconi, Silvana; Colombo, Milena; Andreoni, Vincenza; Gianfreda, Liliana

    2008-02-01

    Two mixed bacterial cultures (C(B-BT) and C(I-AT)) degraded phenanthrene when it was: (i) in the presence of either hexadecane as a non aqueous phase liquid or a montmorillonite-Al(OH)x-humic acid complex as a model organo-mineral matrix; (ii) sorbed to the complex, either alone or in the presence of hexadecane. The cultures had different kinetic behaviours towards phenanthrene with or without hexadecane. The degradation of Phe alone as well as that of Phe in hexadecane ended in 8 and 15 days with C(B-BT) and C(I-AT) cultures, respectively. Hexadecane increased Phe bioavailability for C(I-AT) bacteria which degraded Phe according to first-order kinetics. The same effect was observed for C(B-BT) bacteria, but with an initial 2 days lag phase and in accordance with zero-order kinetics. The presence of hexadecane did not affect the degradation of phenanthrene sorbed and aged on the complex by C(I-AT )culture. This capability was exhibited also after experimental aging of 30 days. The dynamics of the bacterial community composition was investigated through PCR-DGGE (denaturing gradient gel electrophoresis) of 16S rRNA gene fragments. Individual bands changed their intensity during the incubation time, implying that particular microbe's relative abundance changed according to the culture conditions. Isolation of phenanthrene and/or hexadecane degraders was in accord with cultivation-independent data. Growth-dependent changes in the cell surface hydrophobicity of the two cultures and of the isolates suggested that modulation of cell surface hydrophobicity probably played an important role for an efficient phenanthrene assimilation/uptake.

  9. Sorption of polar and nonpolar aromatic compounds to two humic acids with varied structural heterogeneity

    SciTech Connect

    Sun, H.Y.; Zhu, D.Q.; Mao, J.D.

    2008-12-15

    The major objective of the present study was to evaluate the correlation between structural nature of humic acids (HAs) and sorption affinity of organic compounds with varied polarity. We compared the sorption behavior of three aromatic compounds-nonpolar phenanthrene (PHEN) and 1,2,4,5-tetrachlorobenzene (TeCB) and highly polar 2,4-dichlorophenol (DCP)-to a solid-phase coal humic acid (CHA) and a soil humic acid (SHA) suspended in aqueous solution. The structural nature of HAs was characterized using elemental analysis, ultraviolet absorbance, diffusive reflectance Fourier-transform infrared, and solid-state C-13 nuclear magnetic resonance. The two tested HAs have very different structural properties: CHA consists primarily of poly(methylene)-rich aliphatics with high aromatic content and some COO/N-C=O but low polarity, while SHA consists of young materials of lignin, carbohydrates, and peptides with high polarity. In response to the structural heterogeneity of HAs, sorption of nonpolar and more hydrophobic solutes (PHEN, TeCB) to CHA is much greater than that to SHA because of the predominance of hydrophobic effects; however, disparities in sorption affinity between the two HAs become smaller for polar and less hydrophobic DCP because of the major role played by polar interactions. The influence of pH on the sorption of different solutes to the two HAs was also discussed. The results of the present work highlight the importance of structural heterogeneity of both solutes and HAs in the sorption process.

  10. Evaluating phenanthrene sorption on various wood chars

    USGS Publications Warehouse

    James, G.; Sabatini, D.A.; Chiou, C.T.; Rutherford, D.; Scott, A.C.; Karapanagioti, H.K.

    2005-01-01

    A certain amount of wood char or soot in a soil or sediment sample may cause the sorption of organic compounds to deviate significantly from the linear partitioning commonly observed with soil organic matter (SOM). Laboratory produced and field wood chars have been obtained and analyzed for their sorption isotherms of a model solute (phenanthrene) from water solution. The uptake capacities and nonlinear sorption effects with the laboratory wood chars are similar to those with the field wood chars. For phenanthrene aqueous concentrations of 1 ??gl-1, the organic carbon-normalized sorption coefficients (log Koc) ranging from 5.0 to 6.4 for field chars and 5.4-7.3 for laboratory wood chars, which is consistent with literature values (5.6-7.1). Data with artificial chars suggest that the variation in sorption potential can be attributed to heating temperature and starting material, and both the quantity and heterogeneity of surface-area impacts the sorption capacity. These results thus help to corroborate and explain the range of log Koc values reported in previous research for aquifer materials containing wood chars. ?? 2004 Elsevier Ltd. All rights reserved.

  11. Phenanthrene degradation by Biejerinickia sp. B8/36

    SciTech Connect

    Strandberg, G.W.; Abraham, T.J. Jr.; Frazier, G.C.

    1986-01-01

    The use of fossil fuels has greatly increased the ubiquity of polynuclear aromatic hydrocarbons (PAHs) in the environment, and their potential toxicity has generated considerable interest in the ability of microorganisms to utilize and/or detoxify these pollutants. One PAH of concern is phenanthrene. Numerous microbial species are known to degrade phenanthrene and there appear to be several metabolic routes available, depending upon the species, strain, and even the cultural conditions. Although there is a substantial amount of literature on the metabolic pathways of phenanthrene utilization, the authors have found little information regarding the effects of environmental conditions on phenanthrene degradation rates. Such information would be of importance to understanding the fate of this compound in natural and controlled (i.e., wastewater treatment) biological systems. During preliminary experiments, the authors found Beijerinickia sp. B3/36 to be unable to grow solely on phenanthrene, but capable of growth and phenanthrene utilization when yeast extract was supplied. The authors discuss the effects of pH and temperature on growth and phenanthrene degradation by intact cells of Biejerinickia sp. B8/36.

  12. Factors affecting sequestration and bioavailability of phenanthrene in soils

    SciTech Connect

    White, J.C.; Kelsey, J.W.; Hatzinger, P.B.; Alexander, M.

    1997-10-01

    A study was conducted to determine factors affecting the sequestration and changes in bioavailability as phenanthrene persists in soils. Phenanthrene became sequestered in seven soils differing appreciably in organic matter and clay content as measured by earthworm uptake, bacterial mineralization, or extractability. Phenanthrene also became sequestered as it aged in soil aggregates of various sizes as measured by decline in availability to a bacterium, a mild extractant, or both. Wetting and drying a soil during aging reduced the amount of phenanthrene recovered by a mild extractant and the rate and extent of bacterial mineralization of the hydrocarbon. After biodegradation of phenanthrene added to the soil, more of the compound remained if it had been aged than if it had not been aged. Wetting and drying the soil during aging further increased the amount of phenanthrene remaining after biodegradation. The rate and extent of bacterial mineralization of phenanthrene were less in leached than in unleached soil. Aging/sequestration is thus markedly affected by soil properties and environmental factors.

  13. [Effects of dissolved organic matter on phenanthrene adsorption by soil].

    PubMed

    Xiong, Wei; Ling, Wan-ting; Gao, Yan-zheng; Li, Qiu-ling; Dai, Jing-yu

    2007-02-01

    This paper studied the effects of exotic and native dissolved organic matter (DOM) on the phenanthrene adsorption by three soils differed in soil organic carbon content (foc). The exotic DOM came from decayed rice straw, while the native DOM was extracted from the test soils. In all cases, the adsorption of phenanthrene by treated soils could be well described with linear-type model, and there was a positive correlation between adsorption coefficient (Kd) and foc Compared with the control, the Kd value of test soils after native DOM removed was increased by 7. 08% -21. 4% , and the increment (deltaKd) was positively correlated with fo,, indicating that the presence of soil native DOM impeded the phenanthrene adsorption by soil. The effects of exotic DOM on phenanthrene adsorption had a close relation with its added concentration in soil-water system. Within the range of 0-106 mg DOC x L(-1) , the K, value increased first, and then decreased with the increase of added exotic DOM concentration. Lower concentrations of added exotic DOM promoted the phenanthrene adsorption by soil, while higher concentrations ( I> or =52 mg DOC x L(-1)) of it obviously impeded this adsorption. These effects of exotic and native DOM on soil phenanthrene adsorption were considered to be related to the association of phenanthrene with DOM in solution, and the ' cumulative adsorption effect' between soil solid and aqueous phases.

  14. Toxic effect of biosurfactant addition on the biodegradation of phenanthrene.

    PubMed

    Shin, Kyung-Hee; Ahn, Yeonghee; Kim, Kyoung-Woong

    2005-11-01

    The effect of the biosurfactant rhamnolipid on phenanthrene biodegradation and cell growth of phenanthrene degraders was investigated. To compare the effect of rhamnolipid addition, two bacterial strains, 3Y and 4-3, which were isolated from a diesel-contaminated site in Korea, were selected. Without the biosurfactant, large amounts of phenanthrene were degraded with both strains at neutral pH, with higher rates of phenanthrene degradation when the cell growth was higher. Upon the addition of 240 mg/L rhamnolipid, the phenanthrene degradation and optical density were reduced, with this inhibitory effect similar for both 3Y and 4-3. To explain this inhibition, the cell growths of both strains were monitored with various concentrations of rhamnolipid, which showed significant toxic effects toward strain 3Y, but was nontoxic toward 4-3. Combining the inhibitory and toxicity results with regard to the biodegradation, different mechanisms can be suggested for each strain. In the biodegradation experiments, the toxicity of rhamnolipid itself mainly was responsible for the inhibitory effect in the case of 3Y, whereas the toxicity of solubilized phenanthrene or the increased toxicity of rhamnolipid in the presence of solubilized phenanthrene could have resulted in the inhibitory effect in the case of 4-3. This study demonstrated that the effectiveness of biosurfactant-enhanced biodegradation can be significantly different depending on the strain, and the toxicity of the biosurfactant should be considered as an important factor.

  15. Preparative isolation of aquatic humic substances

    USGS Publications Warehouse

    Thurman, E.M.; Malcolm, R.L.

    1981-01-01

    A useful procedure has been developed which utilizes adsorption chromatography followed by size-exclusion chromatography, hydrogen saturation by ion exchange, and lypholization to obtain low-ash aqueous humic substances. The preparative concentration of aquatic humic substances is done by multiple reconcentration procedures even though initial concentrations of aqueous humus may be less than 25 ??g/L. The procedure yields concentration factors of 25 000 times for both humic and fulvic acid in water.

  16. Effect and localization of phenanthrene in maize roots.

    PubMed

    Dupuy, Joan; Leglize, Pierre; Vincent, Quentin; Zelko, Ivan; Mustin, Christian; Ouvrard, Stéphanie; Sterckeman, Thibault

    2016-04-01

    Polycyclic aromatic hydrocarbons (PAHs) have a toxic effect on plants, which limits the efficiency of phytomanagement of contaminated soils. The mechanisms underlying their toxicity are not fully understood. A cultivation experiment was carried out with maize, used as model plant, exposed to sand spiked with phenanthrene (50 or 150 mg kg(-1) dw). Epi-fluorescence microscopic observation of root sections was used to assess suberization of exodermis and endodermis and phenanthrene localization along the primary root length. For 10 days of cultivation, exodermis and endodermis suberization of exposed maize was more extensive. However, after 20 days of exposure, exodermis and endodermis of non-exposed roots were totally suberized, whilst PHE-exposed roots where less suberized. Early extensive suberization may act as barrier against PHE penetration, however longer exposure inhibits root maturation. Phenanthrene patches were located only near suberized exodermis and endodermis, which may therefore act as retention zones, where the hydrophobic phenanthrene accumulates during its radial transport.

  17. Effects of surfactants on extraction of phenanthrene in spiked sand.

    PubMed

    Chang, M C; Huang, C R; Shu, H Y

    2000-10-01

    Problems associated with polynuclear aromatic hydrocarbon (PAH) contaminated site in environmental media have received increasing attention. To resolve such problems, innovative in situ methods are urgently required. This work investigated the feasibility of using surfactants to extract phenanthrene on spiked sand in a batch system. Phenanthrene was spiked into Ottawa sand to simulate contaminated soil. Six surfactants, Brij 30 (BR), Triton X-100 (TR), Tergitol NP-10 (TE), Igepal CA-720 (IG), sodium dodecyl sulfate (SDS) and hexadecyl trimethyl ammonium bromide (HTAB) were used. Adjusting the extraction time, mixing speed and surfactant concentration yielded the optimum extracting conditions. The concentration of phenanthrene was identified with HPLC. Under the experimental conditions, results indicated that those surfactants were highly promising on site remediation since the residual phenanthrene concentration was effectively reduced. The optimum operating conditions were obtained at 30 min, 125 rpm and surfactant concentrations in 4%.

  18. Pentachlorophenol and phenanthrene biodegradation in creosote contaminated aquifer material.

    PubMed

    Mohammed, S A; Sorensen, D L; Sims, R C; Sims, J L

    1998-07-01

    Contamination of the subsurface environment at the Libby Superfund Site, Montana, includes polycyclic aromatic hydrocarbons and f1p4achlorophenol due to accidental spills and improper disposal of wood preserving wastes. Biodegradation is a treatment technology gaining wide application in the treatment of hazardous waste sites. A microcosm study was conducted to evaluate the effect of temperature, sampling depth, nutrient addition, and oxygen on the biodegradation potential of phenanthrene and pentachlorophenol in aquifer samples using radiolabeled chemicals. Mineralization of phenanthrene reached 14% but was less than 1% for pentachlorophenol over the 56 day incubation period. Phenanthrene mineralization in microcosms at 10 degrees C was not significantly different from those at 20 degrees C. This may have been due to microbial community acclimation to lower temperatures at the site. Average volatilization was less than 2% for both phenanthrene and pentachlorophenol. After 56 days, most of the radiolabeled chemical was either solvent extractable or soil bound.

  19. Bioaccumulation and toxicity of phenanthrene applied to different freshwater algae

    SciTech Connect

    Hailing-Sorensen, B.; Nyholm, N.; Rucker, N.; Peterson, H.

    1994-12-31

    Phenanthrene, a polycyclic aromatic hydrocarbon of medium lipophilicity (log K{sub ow} = 4.46) was chosen as a model compound for investigating mechanisms of bioaccumulation of hydrophobic chemicals in microalgae and relations between expressed toxicity and bioaccumulation. {sup 14}C labelled phenanthrene was used for easy quantification of its phase distribution. Results obtained with the green algae Selenastrum capricornutum and Scenedesmus armatus will be presented together with additional results from planned experiments with diatoms and cyanobacteria and interpreted considering cell size and lipid content of the different algae, For the same species bioconcentration factors (BCFs) were influenced to some extent by nutritional status and were slightly higher for unwashed cells than for washed cells. Much surprisingly, however, BCFs increased strongly with decreasing cell concentration. With chemostat grown nutrient deficient and washed Selenastrum cells, for example, the following BCF figures (mg phenanthrene/mg dry weight) were found: 3.8{center_dot}10{sup 4} 1.7{center_dot}10{sup 5} and 1.6{center_dot}10{sup 6}. Sorption of phenanthrene onto algae was rapid. Similar results have been reported in the literature for other compounds. The toxicity of phenanthrene increased with decreasing algal cell concentration probably as a result of increasing BCF`S. Toxicity experiments comprised both short term {sup 14}C assimilation assays and growth tests, and the phase distribution of phenanthrene was accounted for.

  20. Cosolvent-enhanced electrokinetic remediation of soils contaminated with phenanthrene

    SciTech Connect

    Li, A.; Cheung, K.A.; Reddy, K.R.

    2000-06-01

    This research was carried out to evaluate feasibility of using an electrokinetic technique to remove hydrophobic organic pollutants from soils, with the assistance of a cosolvent (n-butylamine, tetrahydrofuran, or acetone) added to the conducting fluid. The experiments were carried out on glacial till clay with phenanthrene as the test compound. Desorption equilibrium was investigated by batch tests. The electrokinetic experiments were conducted using a 19.1 cm long x 6.2 cm inside diameter column under controlled voltage. Water or 20% (volume) cosolvent solution was constantly supplied at the anode. The concentration of phenanthrene in the effluent collected at the cathode was monitored. Each experiment lasted for 100 to 145 days. Results showed that the presence of n-butylamine significantly enhanced the desorption and electrokinetic transport of phenanthrene; about 43% of the phenanthrene was removed after 127 days or 9 pore volumes. The effect of acetone was not as significant as butylamine. The effluent flow in the tetrahydrofuran experiments was minimal, and phenanthrene was not detected in the effluent. The use of water as the conducting solution did not cause observable phenanthrene migration.

  1. Toxic photoproducts of phenanthrene and anthracene in sunlight

    SciTech Connect

    Duxbury, C.L.; McConkey, B.J.; Mallakin, A.; Dixon, D.G.; Greenberg, B.M.

    1995-12-31

    Phenanthrene and anthracene, two of the most prevalent PAHs, undergo significant increases in toxicity on exposure to sunlight. Over a period of several days exposure to light, the toxicity of an aqueous solution of phenanthrene or anthracene increased dramatically. This increase in toxicity is largely due to the primary products formed by these two PAHs due to light exposure. These compounds are more toxic than the parent compounds at equimolar concentrations. Although anthracene is a potent photosensitizer, phenanthrene did not exhibit a significant increase in toxicity due to photosensitization. Photo-oxidation was the principal cause of photoinduced toxicity, with 9,10-phenanthrenequinone being the primary product. This compound is more water soluble than phenanthrene increasing its bioavailability. In addition, mixtures of phenanthrene and 9,10-phenanthrenequinone exhibited toxicity similar to the quinone added alone. This was shown by joint toxicity testing using Lemna gibba and Daphnia magna. These two organisms are currently being used in the lab to further test individual oxidized products of anthracene and phenanthrene that occur as a result of exposure to sunlight.

  2. Comparative study of the solid-matrix luminescence properties of perdeuterated phenanthrene and phenanthrene adsorbed on several solid matrices

    SciTech Connect

    Ramasamy, S.M.; Hurtubise, R.J.

    1996-09-01

    Temperature was varied over a wide range to determine its effect on the luminescence properties of deuterated phenanthrene and phenanthrene adsorbed on a number of solid matrices. Not only were insights into the effects of temperature and solid matrices on the luminescence properties acquired but also the deuterium isotope effect revealed unique information about the role played by the solid matrix in the luminescence of the model compounds. In addition, comparisons of nonradiative rate constants and the efficiencies of intersystem crossing revealed important differences among the solid matrices in altering these parameters. The perdeuterated phenanthrene and phenanthrene proved to be useful probes for investigating the effects of solid matrices on the excited triplet state of phosphors because the excited singlet state of the lumiphor was affected very little by the solid matrices, and the rate constants of phosphorescence for the two phosphors are essentially the same. {copyright} {ital 1996 Society for Applied Spectroscopy.}

  3. 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.

  4. Equivalent weight of humic acid from peat

    USGS Publications Warehouse

    Pommer, A.M.; Breger, I.A.

    1960-01-01

    By means of discontinuous titration, the equivalent weight of humic acid isolated from a peat was found to increase from 144 to 183 between the third and fifty-second day after the humic acid was dissolved. Infra-red studies showed that the material had probably condensed with loss of carbonyl groups. ?? 1960.

  5. Characterization and Phenanthrene Sorption of Natural and Pyrogenic Organic Matter Fractions.

    PubMed

    Jin, Jie; Sun, Ke; Wang, Ziying; Yang, Yan; Han, Lanfang; Xing, Baoshan

    2017-03-07

    Pyrogenic humic acid (HA) is released into the environment during the large-scale application of biochar. However, the biogeochemistry of pyrogenic organic matter (PyOM) fractions and their sorption of hydrophobic organic compounds (HOCs) are poorly understood in comparison with natural organic matter (NOM) fractions. HA and humin (HM) fractions isolated from soils and the oxidized biochars were characterized. Sorption of phenanthrene (PHE) by these fractions was also examined. The characterization results demonstrate that pyrogenic HAs are different from natural HAs, with the former having lower atomic H/C ratios, more abundant aromatic C, and higher concentrations of surface carboxylic groups. Compared with the fresh biochars, the Koc of PHE on their oxidized biochars, pyrogenic HA, and HM fractions were undiminished, which is encouraging for the use of biochar in soil remediation. The PyOM fractions exhibited stronger nonlinear sorption than the NOM fractions. In addition, the PyOM fractions had higher sorption capacity than the NOM fractions due to their low polar C content and high aryl C content. The results obtained from this work will shed new light on the impact of the addition of biochar on the biogeochemistry of soil organic matter and on the fate of HOCs in biochar-amended soil.

  6. Role of structure and microporosity in phenanthrene sorption by natural and engineered organic matter.

    PubMed

    Han, Lanfang; Sun, Ke; Jin, Jie; Wei, Xin; Xia, Xinghui; Wu, Fengchang; Gao, Bo; Xing, Baoshan

    2014-10-07

    Natural sorbents including one humic acid (HA), humins (HMs), nonhydrolyzable carbons (NHCs), and engineered sorbents (biochars) were subject to bleaching to selectively remove a fraction of aromatic C. The structural properties and sorption isotherm data of phenanthrene (Phen) by original and bleached sorbents were obtained. Significant correlations between Phen Koc values by all sorbents and their organic carbon (OC)-normalized CO2 cumulative surface area (CO2-SA/OC) suggested that nanopore-filling mechanism could dominate Phen sorption. After bleaching, natural sorbents still contained large amounts of aromatic C, which are resistant to bleaching, suggesting that they are derived from condensed or nonbiodegradable organic matter (OM). After eliminating the effect of aromatic C remaining in the bleached samples, a general trend of increasing CO2-SA/OC of natural sorbents with increasing aliphaticity was observed, suggesting that nanopores of natural sorbents are partially derived from their aliphatic moieties. Conversely, positive relationships between CO2-SA/OC or Phen logKoc of engineered sorbents and their aromaticity indicated the aromatic structures of engineered sorbents primarily contribute to their nanopores and dominate their sorption of HOCs. Therefore, this study clearly demonstrated that the role of structure and microporosity in Phen sorption is dependent on the sources of sorbents.

  7. Sorption of phenanthrene on to soil fractions in the presence of Triton X-100.

    PubMed

    Zhang, Guangzhi; Sun, Weiling; Hu, Hao; Lu, Xuemei; Ni, Jinren

    2012-01-01

    The objective of this study was to evaluate the effect of soil fractions on surfactant-enhanced soil remediation. A soil sample was separated into humic acid (HA), humin (HM), base-extracted soil (BE) and mineral fraction through solution extraction. The sorption of phenanthrene (PHE) on to individual soil fractions in the presence of a nonionic surfactant, Triton X-100 (TX100) at two concentrations, was studied. The results showed that HA had the highest affinity for both PHE and TX100. The HM and BE presented a high sorption capacity for PHE but a low capacity for TX100, while mineral presented a low sorption capacity for PHE and a high sorption capacity for TX100. The sorption of PHE on different soil fractions was greatly influenced by the presence of TX100. With TX100 present in solution, the distribution parameters K(f) and K(d) of all the sorbents decreased, with the exception of the mineral fraction at the lower TX100 initial concentration. The sorption of PHE on to HA and the mineral fraction was particularly influenced by TX100, which is because of the corresponding high TX100 sorption capacity of HA and the mineral fraction.

  8. Using biodegradation kinetics to measure availability of aged phenanthrene to bacteria inoculated into soil

    SciTech Connect

    Schwartz, E.; Scow, K.M.

    1999-08-01

    The rate of biodegradation of pollutants in soil can be limited by the pollutant's availability to microorganisms. The authors have developed a bioassay for the availability of phenanthrene to bacteria that degrade phenanthrene in soil. The assay uses a soil in which phenanthrene is degraded very slowly. The rate of phenanthrene mineralization in this soil may be increased substantially through bioaugmentation with a bacterial inoculum. By delaying inoculation, it is possible to manipulate the time phenanthrene is present in soil before accelerated biodegradation begins. A phenanthrene concentration much lower than the affinity constant of the inoculum is added; thus, biodegradation kinetics approach first order. Because the phenanthrene first-order rate constant for the inoculum is the same regardless of the phenanthrene residence time in soil, the change in phenanthrene availability to the inoculum can be measured over time. The availability of phenanthrene to bacteria declined in a biphasic double exponential pattern with time. The initial rapid decline in availability resembled the change in amount of phenanthrene extracted from soil with hexane-water. However, after phenanthrene had been present in the soil longer than 300 h, the fraction extracted with hexane-water declined faster than the substrate available to the bacterial inoculum, suggesting that the bacteria are able to access a pool of phenanthrene unavailable to hexane.

  9. H(+)/phenanthrene symporter and aquaglyceroporin are implicated in phenanthrene uptake by wheat (Triticum aestivum L.) roots.

    PubMed

    Zhan, Xinhua; Zhang, Xiaobin; Yin, Xiaoming; Ma, Hengliang; Liang, Jianru; Zhou, Lixiang; Jiang, Tinghui; Xu, Guohua

    2012-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous organic pollutants that are toxic to human and nonhuman organisms. Dietary intake of PAHs is a dominant route of exposure for the general population because food crops are a major source of dietary PAHs. The mechanism for crop root uptake of PAHs remains unclear. Here we reveal that wheat root uptake of PAHs involves active and passive processes. The passive uptake is mercury and glycerol dependent. Mercury and glycerol inhibit uptake, indicating that aquaglyceroporins sensitive to mercury contribute to passive uptake. Active uptake is mediated by a phenanthrene/H symporter. The electrical response of wheat roots triggered by phenanthrene consists of two sequential phases: depolarization followed by repolarization. The depolarization is phenanthrene concentration dependent, with saturation kinetics that have an apparent of K(m) 10.8 μmol L(-1). As uptake proceeds, external solution pH increase is noticed. Lower pH favors the uptake. Vanadate and 2,4-dinitrophenol suppress the electrical response to phenanthrene and phenanthrene uptake, suggesting that plasma membrane H(+)-ATPase is involved in the establishment of an electrochemical proton gradient acting as a driving force for active uptake. Therefore, it is suggested that aquaglyceroporin and phenanthrene/H symporter are implicated in phenanthrene uptake. Our results provide insight into PAH uptake mechanism in wheat roots that is relevant to strategies for reducing PAH accumulation in wheat for food safety, improving phytoremediation of PAH-contaminated soils or water by agronomic practices and genetic modification to target remedial plants for higher PAH uptake capacity.

  10. Effect of Model Sorptive Phases on Phenanthrene Biodegradation: Different Enrichment Conditions Influence Bioavailability and Selection of Phenanthrene-Degrading Isolates

    PubMed Central

    Grosser, Robert J.; Friedrich, Michael; Ward, David M.; Inskeep, William P.

    2000-01-01

    The sorption of organic contaminants by natural organic matter (NOM) often limits substrate bioavailability and is an important factor affecting microbial degradation rates in soils and sediments. We hypothesized that reduced substrate bioavailability might influence which microbial assemblages are responsible for contaminant degradation under enrichment culture conditions. Our primary goal was to characterize enrichments in which different model organic solid phases were used to establish a range of phenanthrene bioavailabilities for soil microorganisms. Phenanthrene sorption coefficients (expressed as log KD values) ranged from 3.0 liters kg−1 for Amberlite carboxylic acid cation-exchange resin (AMB) to 3.5 liters kg−1 for Biobeads polyacrylic resin (SM7) and 4.2 liters kg−1 for Biobeads divinyl benzene resin (SM2). Enrichment cultures were established for control (no sorptive phase), sand, AMB, SM7, and SM2 treatments by using two contaminated soils (from Dover, Ohio, and Libby, Mont.) as the initial inocula. The effects of sorption by model phases on the degradation of phenanthrene were evaluated for numerous transfers in order to obtain stable microbial assemblages representative of sorptive and nonsorptive enrichment cultures and to eliminate the effects of the NOM present in the initial inoculum. Phenanthrene degradation rates were similar for each soil inoculum and ranged from 4 to 5 μmol day−1 for control and sand treatments to approximately 0.4 μmol day−1 in the presence of the SM7 sorptive phase. The rates of phenanthrene degradation in the highly sorptive SM2 enrichment culture were insignificant; consequently, stable microbial populations could not be obtained. Bacterial isolates obtained from serial dilutions of enrichment culture samples exhibited significant differences in rates of phenanthrene degradation performed in the presence of SM7, suggesting that enrichments performed in the presence of a sorptive phase selected for different

  11. Bioventing remediation and ecotoxicity evaluation of phenanthrene-contaminated soil.

    PubMed

    García Frutos, F Javier; Escolano, Olga; García, Susana; Babín, Mar; Fernández, M Dolores

    2010-11-15

    The objectives of soil remediation processes are usually based on threshold levels of soil contaminants. However, during remediation processes, changes in bioavailability and metabolite production can occur, making it necessary to incorporate an ecotoxicity assessment to estimate the risk to ecological receptors. The evolution of contaminants and soil ecotoxicity of artificially phenanthrene-contaminated soil (1000 mg/kg soil) during soil treatment through bioventing was studied in this work. Bioventing was performed in glass columns containing 5.5 kg of phenanthrene-contaminated soil and uncontaminated natural soil over a period of 7 months. Optimum conditions of mineralisation (humidity=60% WHC; C/N/P=100:20:1) were determined in a previous work. The evolution of oxygen consumption, carbon dioxide production, phenanthrene concentration and soil toxicity were studied on sacrificed columns at periods of 0, 3 and 7 months. Toxicity to soil and aquatic organisms was determined using a multispecies system in the soil columns (MS-3). In the optimal bioventing treatability test, we obtained a reduction rate in phenanthrene concentration higher that 93% after 7 months of treatment. The residual toxicity obtained at the end of the treatment was not attributed to the low phenanthrene concentration, but to the ammonia used to restore the optimal C/N ratio.

  12. Relative role of eukaryotic and prokaryotic microorganisms in phenanthrene transformation in coastal sediments

    SciTech Connect

    MacGillivray, A.R.; Shiaris, M.P. )

    1994-04-01

    The relative role of eukaryotic versus prokaryotic microorganisms in phenanthrene transformation was measured in slurries of coastal sediment by two different approaches: detection of marker metabolites and use of selective inhibitors on phenanthrene biotransformation. Phenanthrene biotransformation was measured by polar metabolite formation and CO[sub 2] evolution from [9-[sup 14]C]phenanthrene. Both yeasts and bacteria transformed phenanthrene in slurries of coastal sediment. Two products of phenanthrene oxidation by fungi, phenanthrene trans-3,4-dihydrodiol and 3-phenanthrol, were produced in yeast-inoculated sterile sediment. However, only products of phenanthrene oxidation typical of bacterial transformation, 1-hydroxy-2-naphthoic acid and phenanthrene cis-3,4-dihydrodiol, were isolated from slurries of coastal sediment with natural microbial populations. Phenanthrene trans-dihydrodiols or other products of fungal oxidation of phenanthrene were not detected in the slurry containing a natural microbial population. A predominant role for bacterial transformation of phenanthrene was also suggested from selective inhibitor experiments. Addition of streptomycin to slurries, at a concentration which suppressed bacterial viable counts and rates of [methyl-[sup 3]H]thymidine uptake, completely inhibited phenanthrene transformation. Treatment with colchicine, at a concentration which suppressed yeast viable counts, depressed phenanthrene transformation by 40%, and this was likely due to nontarget inhibition of bacterial activity. The relative contribution of eukaryotic microorganisms to phenanthrene transformation in inoculated sterile sediment was estimated to be less than 3% of the total activity. We conclude that the predominant degraders of phenanthrene in muddy coastal sediments are bacteria and not eukaryotic microorganisms. 35 refs., 2 figs., 1 tab.

  13. Relative Role of Eukaryotic and Prokaryotic Microorganisms in Phenanthrene Transformation in Coastal Sediments

    PubMed Central

    MacGillivray, A. Ronald; Shiaris, Michael P.

    1994-01-01

    The relative role of eukaryotic versus prokaryotic microorganisms in phenanthrene transformation was measured in slurries of coastal sediment by two different approaches: detection of marker metabolites and use of selective inhibitors on phenanthrene biotransformation. Phenanthrene biotransformation was measured by polar metabolite formation and CO2 evolution from [9-14C]phenanthrene. Radiolabeled metabolites were tentatively identified by high-performance liquid chromatography (HPLC) separation combined with UV/visible spectral analysis of HPLC peaks and comparison to authentic standards. Both yeasts and bacteria transformed phenanthrene in slurries of coastal sediment. Two products of phenanthrene oxidation by fungi, phenanthrene trans-3,4-dihydrodiol and 3-phenanthrol, were produced in yeast-inoculated sterile sediment. However, only products of phenanthrene oxidation typical of bacterial transformation, 1-hydroxy-2-naphthoic acid and phenanthrene cis-3,4-dihydrodiol, were isolated from slurries of coastal sediment with natural microbial populations. Phenanthrene trans-dihydrodiols or other products of fungal oxidation of phenanthrene were not detected in the slurry containing a natural microbial population. A predominant role for bacterial transformation of phenanthrene was also suggested from selective inhibitor experiments. Addition of streptomycin to slurries, at a concentration which suppressed bacterial viable counts and rates of [methyl-3H]thymidine uptake, completely inhibited phenanthrene transformation. Treatment with colchicine, at a concentration which suppressed yeast viable counts, depressed phenanthrene transformation by 40%, and this was likely due to nontarget inhibition of bacterial activity. The relative contribution of eukaryotic microorganisms to phenanthrene transformation in inoculated sterile sediment was estimated to be less than 3% of the total activity. We conclude that the predominant degraders of phenanthrene in muddy coastal

  14. Molecular size of aquatic humic substances

    USGS Publications Warehouse

    Thurman, E.M.; Wershaw, R. L.; Malcolm, R.L.; Pinckney, D.J.

    1982-01-01

    Aquatic humic substances, which account for 30 to 50% of the organic carbon in water, are a principal component of aquatic organic matter. The molecular size of aquatic humic substances, determined by small-angle X-ray scattering, varies from 4.7 to 33 A?? in their radius of gyration, corresponding to a molecular weight range of 500 to greater than 10,000. The aquatic fulvic acid fraction contains substances with molecular weights ranging from 500 to 2000 and is monodisperse, whereas the aquatic humic acid fraction contains substances with molecular weights ranging from 1000 to greater than 10,000 and is generally polydisperse. ?? 1982.

  15. Inoculation of a phenanthrene-degrading endophytic bacterium reduces the phenanthrene level and alters the bacterial community structure in wheat.

    PubMed

    Liu, Juan; Xiang, Yanbing; Zhang, Zhiming; Ling, Wanting; Gao, Yanzheng

    2017-03-28

    Colonization by polycyclic aromatic hydrocarbon (PAH)-degrading endophytic bacteria (PAHDEB) can reduce the PAH contamination risk in plant. However, little information is available on the impact of PAHDEB colonization on the endophytic bacterial community of inner plant tissues. A phenanthrene-degrading endophytic bacterium (PDEB), Massilia sp. Pn2, was inoculated onto the roots of wheat and subjected to greenhouse container experiments. The endophytic bacterial community structure in wheat was investigated using high-throughput sequencing technology. The majority of endophytic bacteria in wheat were Proteobacteria, and the dominant genus was Pseudomonas. Phenanthrene contamination clearly increased the diversity of endophytic bacteria in wheat. The cultivable endophytic bacteria counts in wheat decreased with increasing the level of phenanthrene contamination; the endophytic bacterial community structure changed correspondingly, and the bacterial richness first increased and then decreased. Inoculation of strain Pn2 reduced the phenanthrene contamination in wheat, enlarged the biomass of wheat roots, changed the bacterial community structure and enhanced the cell counts, diversity and richness of endophytic bacteria in phenanthrene-contaminated wheat in a contamination level-dependent manner. The findings of this investigation provide insight into the responses of endophytic bacterial community in plant to external PAH contamination and PAHDEB colonization.

  16. Phenanthrene removal from soil slurries with surfactant-treated oxides

    SciTech Connect

    Park, J.W.; Jaffe, P.R.

    1995-06-01

    A soil-slurry washing technique to decontaminate soils containing low-solubility nonionic organic pollutants was investigated, using phenanthrene as a model pollutant. The technique is based on first transferring the sorbed phenanthrene from the soil to anionic surfactant-coated oxide particles, and then separating these anionic surfactant-coated oxide particles with the sorbed phenanthrene from the soil slurry via a magnetic separation technique. The decontamination of two soils with different particle sizes and soil organic matter content was investigated. The proposed soil-slurry washing technique was effective in removing a strongly sorbing nonionic organic contaminant from soil slurries. Various operational scenarios of multistage soil-slurry reactors were evaluated with a mathematical model.

  17. Plasmid-mediated mineralization of naphthalene, phenanthrene, and anthracene

    SciTech Connect

    Sanseverino, J. IT Corp., Knoxville, TN ); Applegate, B.M.; King, J.M.H.; Sayler, G.S. )

    1993-06-01

    The biochemistry and genetics of the naphthalene degradation pathway contained on plasmid NAH7 have been well characterized. However, not much is known about the substrate specificity of the enzymes of nah operons and whether the nah-encoded enzymes are capable of metabolizing higher polyaromatic hydrocarbons. This paper shows that NAH7 and NAH7-like plasmids can mediate metabolism of phenanthrene and anthracene as well as naphthalene. In addition, a mutant blocked in the nahG (salicylate hydroxylase) gene produced unidentified metabolites when it is grown in the presence of phenanthrene and anthracene. This implies that phenanthrene and anthracene are degraded through the nah plasmid-encoded system. 29 refs., 3 figs., 2 tabs.

  18. Superconductivity at 5 K in alkali-metal-doped phenanthrene.

    PubMed

    Wang, X F; Liu, R H; Gui, Z; Xie, Y L; Yan, Y J; Ying, J J; Luo, X G; Chen, X H

    2011-10-18

    Organic superconductors have π-molecular orbitals, from which electrons can become delocalized, giving rise to metallic conductivity due to orbital overlap between adjacent molecules. Here we report the discovery of superconductivity at a transition temperature (T(c)) of ~5 K in alkali-metal-doped phenanthrene. A 1-GPa pressure leads to a 20% increase of T(c), suggesting that alkali-metal-doped phenanthrene shows unconventional superconductivity. Raman spectra indicate that alkali-metal doping injects charge into the system to realize the superconductivity. The discovery of superconductivity in A(3)phenanthrene (where A can be either K or Rb) produces a novel broad class of superconductors consisting of fused hydrocarbon benzene rings with π-electron networks. An increase of T(c) with increasing number of benzene rings from three to five suggests that organic hydrocarbons with long chains of benzene rings are potential superconductors with high T(c).

  19. Molecular aggregation of humic substances

    USGS Publications Warehouse

    Wershaw, R. L.

    1999-01-01

    Humic substances (HS) form molecular aggregates in solution and on mineral surfaces. Elucidation of the mechanism of formation of these aggregates is important for an understanding of the interactions of HS in soils arid natural waters. The HS are formed mainly by enzymatic depolymerization and oxidation of plant biopolymers. These reactions transform the aromatic and lipid plant components into amphiphilic molecules, that is, molecules that consist of separate hydrophobic (nonpolar) and hydrophilic (polar) parts. The nonpolar parts of the molecules are composed of relatively unaltered segments of plant polymers and the polar parts of carboxylic acid groups. These amphiphiles form membrane-like aggregates on mineral surfaces and micelle-like aggregates in solution. The exterior surfaces of these aggregates are hydrophilic, and the interiors constitute separate hydrophobic liquid-like phases.

  20. Americium binding to humic acid.

    PubMed

    Peters, A J; Hamilton-Taylor, J; Tipping, E

    2001-09-01

    The binding of americium (Am) by peat humic acid (PHA) has been investigated at Am concentrations between 10(-1) and 10(-7) M at pH approximately 2.6 in the presence and absence of Cu as a competing ion. Cu-PHA binding was also investigated in order to derive independent binding constants for use in modeling the competitive binding studies. Humic ion-binding model VI was used to compare the acquired data with previously published binding data and to investigate the importance of high-affinity binding sites in metal-PHA binding. Am was not observed to bind to high-affinity, low-concentration binding sites. The model VI parameter deltaLK2 takes into accountthe small number of strong sites in PHA and was found to be important for Cu-PHA binding but not for Am-PHA binding, regardless of whether Cu was present. Analysis of the PHA sample revealed that it contained a considerable quantity of Fe not removed by the extraction procedure, much of which is believed to be present as Fe(III). Model VI was then used to investigate the possible importance of the presence of Fe(III) in the Am-PHA binding experiments. When Fe(III) was assumed to be present, improved descriptions of the data by model VI were obtained by assuming that all of the metals [Am, Cu, and Fe(III)] undergo strong binding. This highlights the importance of Fe(III) competition in metal-PHA binding studies and possible shortcomings in the extraction procedure used to extract PHA.

  1. Immunomodulative properties of humic peat preparations

    NASA Astrophysics Data System (ADS)

    Stepchenko, L. M.; Syedykh, N. J.

    2010-05-01

    It is proved, that the humic peat preparations promote the resistance of plants, animals and poultry to the influence of both abyotyc and byotyc extreme factors of external environment, to action. It was shown by us before, that biologically active compounds from peat promote stability against different diseases of agricultural animals and poultry. We conducted researches of humic preparations influence (hydrohumate and oxyhumate) on several indexes of immunoreactivity of the organisms of chickens broilers, ostriches, cows and laboratory rats. It is found out, that adding of humic preparations to forage or drinking water results in the normalization of immunity indexes; in particular, leucocytes level, in the increase of the level of some classes of immunoglobuline in blood, of haemoglobin level, T- and B-lymphocytes level, as well as common unspecific resistance - lyzocymic, phagocytic and bactericidic activity. These results allow to suggest that the peat humic preparations show immunomodulative activity, influencing both on humoral and cel immunity links.

  2. [Adsorption of phenanthrene from aqueous solution on cetylpyridinium bromide (CPB) -modified zeolite].

    PubMed

    Li, Jia; Lin, Jian-Wei; Zhan, Yan-Hui; Chen, Zu-Mei; Wang, Peng-Jun

    2014-02-01

    Surfactant-modified zeolites (SMZs) with different coverage types were prepared by loading of different amounts of cetylpyridinium bromide (CPB) onto natural zeolites and were used as adsorbents to remove phenanthrene from aqueous solution. The adsorption of phenanthrene from aqueous solution on monolayer and bilayer SMZs as a function of adsorbent dosage, initial phenanthrene concentration, contact time, and temperature was investigated using batch experiments. Results showed monolayer and bilayer SMZs were effective for the removal of phenanthrene from aqueous solution. The phenanthrene removal efficiency of SMZs increased with increasing adsorbent dosage, but the amount of phenanthrene adsorbed on SMZs decreased with increasing adsorbent dosage. The adsorption kinetics of phenanthrene on SMZs well followed a pseudo-second-order kinetic model. The equilibrium adsorption data of phenanthrene on SMZs at a low concentration of phenanthrene in solution could be described by the Linear equation and Freundlich equation. The main mechanism for phenanthrene adsorption onto monolayer SMZ is hydrophobic interaction, and the main mechanism for phenanthrene adsorption onto bilayer SMZ is organic partitioning. The calculated thermodynamic parameters such as Gibbs free energy change (deltaG(theta)), enthalpy changes (deltaH(theta)), and entropy change (deltaS(theta)) showed that the adsorption process of phenanthrene on SMZs is spontaneous and exothermic in nature. When the CPB loading amount of bilayer SMZ was twice as much as that of monolayer SMZ, the phenanthrene adsorption capacity for bilayer SMZ was slightly higher than that for monolayer SMZ. In a conclusion, both monolayer and bilayer SMZs are promising adsorbents for the removal of phenanthrene from water and wastewater, and monolayer SMZ is a more cost-effective adsorbent for phenanthrene removal than bilayer SMZ.

  3. (Biphenyl-2-alkyne) derivatives as common precursors for the synthesis of 9-iodo-10-organochalcogen-phenanthrenes and 9-organochalcogen-phenanthrenes.

    PubMed

    Grimaldi, Tamiris B; Lutz, Guilherme; Back, Davi F; Zeni, Gilson

    2016-11-08

    In this paper, we report our results on the cyclization of (biphenyl-2-alkyne) derivatives to give two different types of phenanthrene derivatives, 9-iodo-10-organochalcogen-phenanthrenes and 9-organochalcogen-phenanthrenes. The strategy for the synthesis was based on the use of electrophilic cyclization for the preparation of 9-iodo-10-organochalcogen-phenanthrenes and iron(iii) chloride/diorganyl diselenide-mediated intramolecular cyclization to prepare 9-organochalcogen-phenanthrenes. The effects of solvent, temperature, reaction time and stoichiometry on the efficiency of cyclization reactions were investigated. The standard reaction conditions were compatible with many functional groups in the substrates, such as methyl, chlorine, fluorine and methoxyl. This protocol was efficient for diorganyl diselenides and disulfides but ineffective for diorganyl ditellurides. The resulting phenanthrenes were further functionalized through Sonogashira reactions followed by the electrophilic cyclization reaction to give the selenophene-fused aromatic compounds.

  4. Two-stage mineralization of phenanthrene by estuarine enrichment cultures

    SciTech Connect

    Guerin, W.F.; Jones, G.E.

    1988-04-01

    The polycyclic aromatic hydrocarbon phenanthrene was mineralized in two stages by soil, estuarine water, and sediment microbial populations. At high concentrations, phenanthrene was degraded, with the concomitant production of biomass and accumulation of Folin-Ciocalteau-reactive aromatic intermediates. Subsequent consumption of these intermediates resulted in a secondary increase in biomass. Analysis of intermediates by high-performance liquid chromatography, thin-layer chromatography, and UV absorption spectrometry showed 1-hydroxy-2-naphthoic acid (1H2NA) to be the predominant product. A less pronounced two-stage mineralization pattern was also observed by monitoring /sup 14/CO/sub 2/ production from low concentrations (0.5 mg liter/sup -1/) of radiolabeled phenanthrene. Here, mineralization of /sup 14/C-labeled 1H2NA could explain the incremental /sup 14/CO/sub 2/ produced during the later part of the incubations. Accumulation of 1H2NA by isolates obtained from enrichments was dependent on the initial phenanthrene concentration. The production of metabolites during polycyclic aromatic hydrocarbon biodegradation is discussed with regard to its possible adaptive significance and its methodological implications.

  5. Effect of surfactant addition on phenanthrene biodegradation in sediments

    SciTech Connect

    Tsomides, H.J.; Hughes, J.B.; Thomas, J.M.; Ward, C.H.

    1995-12-31

    A laboratory study was conducted to determine whether commercial surfactants enhance the bioremediation of PAH-contaminated sediments. Phenanthrene was chosen as a representative PAH. An inoculum of PAH-degrading microorganisms, enriched from an aquatic sediment, was used in sediment-water slurry microcosm biodegradation experiments. Of seven nonionic surfactants tested, only one (Triton X-100) did not inhibit phenanthrene mineralization at concentrations above the critical micelle concentration (CMC). Temporal studies on Triton X-100 revealed that while it initially inhibited mineralization in sediment-free microcosms, after 1 week Triton X-100 slightly improved phenanthrene biotransformation and mineralization in microcosms with and without sediment. For all treatments, phenanthrene disappearance was complete after 9 d. and mineralization reached 50 to 65% after 12 d. Sorption to the sediment appears to have reduced the free aqueous surfactant concentration, thereby reducing surfactant toxicity to the microorganisms. These results suggest that many surfactants are toxic to PAH-degrading microorganisms, and while surfactant addition may not always have adverse effects on biodegradation, the use of surfactants might not be necessary to achieve complete contaminant removal.

  6. Effect of surfactant addition on phenanthrene biodegradation in sediments

    SciTech Connect

    Tsomides, H.J.; Hughes, J.B.; Thomas, J.M.; Ward, C.H.

    1995-06-01

    A laboratory study was conducted to determine whether commercial surfactants enhance the bioremediation of PAH-contaminated sediments. Phenanthrene was chosen as a representative PAH; an inoculum of PAH-degrading microorganisms, enriched from an aquatic sediment, was used in sediment-water slurry microcosm biodegradation experiments. Of seven non-ionic surfactants tested, only one (Triton X-100) did not inhibit phenanthrene mineralization at concentrations above the critical micelle concentration (CMC). Temporal studies on Triton X-100 revealed that while it initially inhibited mineralization in sediment-free microcosms, after 1 week Triton X-100 slightly improved phenanthrene biotransformation and mineralization in microcosms with and without sediment. For all treatments, phenanthrene disappearance was complete after 9 d, and mineralization reached 50 to 65% after 12 d. Sorption to the sediment appears to have reduced the free aqueous surfactant concentration, thereby reducing surfactant toxicity to the microorganisms. These results suggest that many surfactants are toxic to PAH-degrading microorganisms, and while surfactant addition may not always have adverse effects on biodegradation, the use of surfactants might not be desirable to achieve complete contamination removal.

  7. Fluorescence of aqueous solutions of commercial humic products

    NASA Astrophysics Data System (ADS)

    Gosteva, O. Yu.; Izosimov, A. A.; Patsaeva, S. V.; Yuzhakov, V. I.; Yakimenko, O. S.

    2012-01-01

    We have studied the spectral luminescence characteristics of aqueous solutions of humic products obtained from different raw material sources, and their behavior as the excitation wavelength increases from 270 nm to 355 nm. We have identified differences in the spectral properties of industrial humic products from coalified materials, lignin-containing organic waste, and humic products from plant raw material (peat, sapropel, vermicompost). We have shown that humic products from plant raw material have spectral properties closer to those for humic substances in natural water or soil than humic products from coalified materials.

  8. Rhizoremediation of phenanthrene and pyrene contaminated soil using wheat.

    PubMed

    Shahsavari, Esmaeil; Adetutu, Eric M; Taha, Mohamed; Ball, Andrew S

    2015-05-15

    Rhizoremediation, the use of the plant rhizosphere and associated microorganisms represents a promising method for the clean up of soils contaminated with polycyclic aromatic hydrocarbons (PAHs) including phenanthrene and pyrene, two model PAHs. Although numerous studies have been published reporting the degradation of phenanthrene and pyrene, very few evaluate the microbial basis of the rhizoremediation process through the application of molecular tools. The aim of this study was to investigate the effect of wheat on the degradation of two model PAHs (alone or in combination) and also on soil bacterial, fungal and nidA gene (i.e. a key gene in the degradation of pyrene) communities. The addition of wheat plants led to a significant enhancement in the degradation of both phenanthrene and pyrene. In pyrene-contaminated soils, the degradation rate increased from 15% (65 mg/kg) and 18% (90 mg/kg) in unplanted soils to 65% (280 mg/kg) and 70% (350 mg/kg) in planted treatments while phenanthrene reduction was enhanced from 97% (394 mg/kg) and 87% (392 mg/kg) for unplanted soils to 100% (406 mg/kg) and 98% (441 mg/kg) in the presence of wheat. PCR-DGGE results showed that the plant root let to some changes in the bacterial and fungal communities; these variations did not reflect any change in hydrocarbon-degrading communities. However, plate counting, traditional MPN and MPN-qPCR of nidA gene revealed that the wheat rhizosphere led to an increase in the total microbial abundance including PAH degrading organisms and these increased activities resulted in enhanced degradation of phenanthrene and pyrene. This clearer insight into the mechanisms underpinning PAH degradation will enable better application of this environmentally friendly technique.

  9. Effects of sediment resuspension on the degradation of phenanthrene

    SciTech Connect

    LeBlanc, L.A.; Gulnick, J.; Brownawell, B.J.; Taylor, G.T.

    1995-12-31

    Degradation of bulk organic matter in sediments is enhanced by oxic/anoxic cycling, a feature common in coastal sediments which are resuspended into overlying waters. The authors are examining the effect of periodic cycling of sediment between an oxic water column and a reducing sediment bed on polycyclic aromatic hydrocarbon (PAH) degradation by altering resuspension frequency in controlled laboratory exposures. Rates of initial degradation in coastal sediment have been studied for {sup 14}C-labeled phenanthrene in sediments that were suspended at the following frequencies: 12/day, 6/day, 1/day, 0.25/day and 0/day in liter-sized flow through chambers. Results to date show that degradation rates are initially log linear, with the greatest initial rates (2.4--2.7%/day) occurring in the first three treatments. In treatments resuspended less frequently, this rate decreases with time and is followed at 10--12 days, by another rate increase, which may indicate the stimulation of a bacterial subpopulation. Rates of PAH mineralization are tied to the lability and mineralization of other pools of sediment organic matter, that in turn are also affected also by oxic/anoxic cycling. Addition of fresh diatom detritus stimulated the rates of phenanthrene degradation in resuspension experiments where labile organic matter had already been consumed and microbial activity was low; in contrast diatom addition depressed phenanthrene degradation in sediment exposures with more labile organic matter remaining. The authors are further addressing the behavior of phenanthrene in exposures where they vary the concentration of initial phenanthrene and the concentration and nature of co-substrates.

  10. Colonization on root surface by a phenanthrene-degrading endophytic bacterium and its application for reducing plant phenanthrene contamination.

    PubMed

    Liu, Juan; Liu, Shuang; Sun, Kai; Sheng, Yuehui; Gu, Yujun; Gao, Yanzheng

    2014-01-01

    A phenanthrene-degrading endophytic bacterium, Pn2, was isolated from Alopecurus aequalis Sobol grown in soils contaminated with polycyclic aromatic hydrocarbons (PAHs). Based on morphology, physiological characteristics and the 16S rRNA gene sequence, it was identified as Massilia sp. Strain Pn2 could degrade more than 95% of the phenanthrene (150 mg · L(-1)) in a minimal salts medium (MSM) within 48 hours at an initial pH of 7.0 and a temperature of 30 °C. Pn2 could grow well on the MSM plates with a series of other PAHs, including naphthalene, acenaphthene, anthracene and pyrene, and degrade them to different degrees. Pn2 could also colonize the root surface of ryegrass (Lolium multiflorum Lam), invade its internal root tissues and translocate into the plant shoot. When treated with the endophyte Pn2 under hydroponic growth conditions with 2 mg · L(-1) of phenanthrene in the Hoagland solution, the phenanthrene concentrations in ryegrass roots and shoots were reduced by 54% and 57%, respectively, compared with the endophyte-free treatment. Strain Pn2 could be a novel and useful bacterial resource for eliminating plant PAH contamination in polluted environments by degrading the PAHs inside plants. Furthermore, we provide new perspectives on the control of the plant uptake of PAHs via endophytic bacteria.

  11. Study of the degradation activity and the strategies to promote the bioavailability of phenanthrene by Sphingomonas paucimobilis strain 20006FA.

    PubMed

    Coppotelli, Bibiana M; Ibarrolaza, Agustin; Dias, Romina L; Del Panno, Maria T; Berthe-Corti, Luise; Morelli, Irma S

    2010-02-01

    The present study describes the phenanthrene-degrading activity of Sphingomonas paucimobilis 20006FA and its ability to promote the bioavailability of phenanthrene. S. paucimobilis 20006FA was isolated from a phenanthrene-contaminated soil microcosm. The strain was able to grow in liquid mineral medium saturated with phenanthrene as the sole carbon source, showing high phenanthrene elimination (52.9% of the supplied phenanthrene within 20 days). The accumulation of 1-hydroxy-2-naphthoic acid and salicylic acid as major phenanthrene metabolites and the capacity of the strain to grow with sodium salicylate as the sole source of carbon and energy indicated that the S. paucimobilis 20006FA possesses a complete phenanthrene degradation pathway. However, under the studied conditions, the strain was able to mineralize only the 10% of the consumed phenanthrene. Investigations on the cell ability to promote bioavailability of phenanthrene showed that the S. paucimobilis strain 20006FA exhibited low cell hydrophobicity (0.13), a pronounced chemotaxis toward phenanthrene, and it was able to reduce the surface tension of mineral liquid medium supplemented with phenanthrene as sole carbon source. Scanning electron micrographs revealed that: (1) in suspension cultures, cells formed flocks and showed small vesicles on the cell surface and (2) cells were also able to adhere to phenanthrene crystals and to produce biofilms. Clearly, the strain seems to exhibit two different mechanisms to enhance phenanthrene bioavailability: biosurfactant production and adhesion to the phenanthrene crystals.

  12. Humic substance formation during wastewater infiltration

    SciTech Connect

    Siegrist, R.L. ); Hildmann-Smed, R.; Filip, Z.K. , Langen . Inst. fuer Wasser-, Boden- und Lufthygiene); Jenssen, P.D. . Centre for Soil and Environmental Research)

    1991-01-01

    Soil infiltration of wastewater effluents is a widely practiced method of treatment and disposal/reuse throughout the world. Renovation of the wastewater results from a wide variety of complex physicochemical and biological processes. One set of processes is speculated to involve the accumulation of organic matter by filtration and sorption followed by formation of humic substances. This humic substance formation can effect the performance of soil treatment systems by contributing to soil pore clogging and reduction in hydraulic capacity, and by yielding reactive substances and an enhancement of purification processes. While there has been a wealth of research into the nature and genesis of humic substances in terrestrial environments, there has been limited research of humic substance formation during soil infiltration of wastewater. The purpose of the research reported herein was to determine if humic substances can form under conditions typical of those present during wastewater infiltration into natural soil systems. This work was conducted during 1989 to 1990 as a collaborative effort between the Centre for Soil and Environmental Research, located in Aas, Norway and the Institute for Water, Soil and Air Hygiene located in Langen, West Germany. 11 refs., 3 figs., 6 tabs.

  13. The mechanisms by which phenanthrene affects the photosynthetic apparatus of cucumber leaves.

    PubMed

    Jin, Liqiao; Che, Xingkai; Zhang, Zishan; Li, Yuting; Gao, Huiyuan; Zhao, Shijie

    2017-02-01

    Phenanthrene is a polycyclic aromatic hydrocarbon (PAH) that is widely distributed in the environment and seriously affects the growth and development of plants. To clarify the mechanisms of the direct effects of phenanthrene on the plant photosynthetic apparatus, we measured short-term phenanthrene-treated cucumber leaves. Phenanthrene inhibited Rubisco carboxylation activity, decreasing photosynthesis rates (Pn). And phenanthrene inhibited photosystem II (PSII) activity, thereby blocking photosynthetic electron transport. The inhibition of the light and dark reactions decreased the photosynthetic electron transport rate (ETR) and increased the excitation pressure (1-qP). Under high light, the maximum photochemical efficiency of photosystem II (Fv/Fm) in phenanthrene-treated cucumber leaves decreased significantly, but photosystem I (PSI) activity (Δ I/Io) did not. Phenanthrene also caused a J-point rise in the OJIP curve under high light, which indicated that the acceptor side of PSII QA to QB electron transfer was restricted. This was primarily due to the net degradation of D1 protein, which is caused by the accumulation of reactive oxygen species (ROS) in phenanthrene-treated cucumber leaves under high light. This study demonstrated that phenanthrene could directly inhibit photosynthetic electron transport and Rubisco carboxylation activity to decrease net Pn. Under high light, phenanthrene caused the accumulation of ROS, resulting in net increases in D1 protein degradation and consequently causing PSII photoinhibition.

  14. [Enhanced fixation of phenanthrene in soils amended with exotic organic materials].

    PubMed

    Ren, Li-Li; Ling, Wan-Ting; Gao, Yan-Zheng

    2008-03-01

    This paper studied the enhanced fixation of phenanthrene in clay loam soil, sandy silt soil, and silt loam soil under effects of exotic organic materials (EOMs) commercial organic fertilizer and peat. The results showed that after the addition of EOMs, the adsorption isotherms of phenanthrene in test soils were still linear, and distribution was the predominant mechanism for phenanthrene adsorption by soil. The adsorption of phenanthrene was significantly enhanced by the addition of EOMs, and the enhancement of distribution constant (Kd) was positively correlated with the content of soil organic carbon (foc), indicating that the higher the soil foc, the more significant the promotion effect of EOMs addition on phenanthrene adsorption. On the contrary, the desorption of phenanthrene was obviously inhibited by the addition of EOMs. After 64 days of EOMs addition, the extractable amount of phenanthrene was decreased significantly, compared with the control. Since the organic matter content of peat was higher than that of commercial organic fertilizer, the decrease of extractable phenanthrene in soils added with peat was more significant. In addition, the higher the soil foc, the stronger inhibition effect of EOMs on extractability of phenanthrene. On the whole, exotic EOMs could promote the adsorption, while inhibit the desorption and reduce the extractability of phenanthrene in soils.

  15. Solubilities of eta-octadecane, phenanthrene, and eta-octadecane/phenanthrene mixtures in supercritical propane at 390 and 420. Kappa. and pressures to 60 bar

    SciTech Connect

    Dimitrelis, D.; Prausnitz, J.M. )

    1989-07-01

    Solubility data were obtained for n-octadecane, phenanthrene, and a nearly equimolar n-octadecane/phenanthrene mixture in supercritical propane. Solubilities were measured in a flow apparatus at 390 and 420 {Kappa} over the pressure range 35-60 bar. The experimental data is correlated using the perturbed-hard-chain equation of state. Agreement between experiment and correlation is good.

  16. Iodine binding to humic acid.

    PubMed

    Bowley, H E; Young, S D; Ander, E L; Crout, N M J; Watts, M J; Bailey, E H

    2016-08-01

    The rate of reactions between humic acid (HA) and iodide (I(-)) and iodate (IO3(-)) have been investigated in suspensions spiked with (129)I at concentrations of 22, 44 and 88 μg L(-1) and stored at 10 °C. Changes in the speciation of (129)I(-), (129)IO3(-) and mixed ((129)I(-) + (129)IO3(-)) spikes were monitored over 77 days using liquid chromatography inductively coupled plasma mass spectrometry (LC-ICP-MS). In suspensions spiked with (129)I(-) 25% of the added I(-) was transformed into organic iodine (Org-(129)I) within 77 days and there was no evidence of (129)IO3(-) formation. By contrast, rapid loss of (129)IO3(-) and increase in both (129)I(-) and Org-(129)I was observed in (129)IO3(-)-spiked suspensions. However, the rate of Org-(129)I production was greater in mixed systems compared to (129)IO3(-)-spiked suspensions with the same total (129)I concentration, possibly indicating IO3(-)I(-) redox coupling. Size exclusion chromatography (SEC) demonstrated that Org-(129)I was present in both high and low molecular weight fractions of the HA although a slight preference to bond with the lower molecular weight fractions was observed indicating that, after 77 days, the spiked isotope had not fully mixed with the native (127)I pool. Iodine transformations were modelled using first order rate equations and fitted rate coefficients determined. However, extrapolation of the model to 250 days indicated that a pseudo-steady state would be attained after ∼200 days but that the proportion of (129)I incorporated into HA was less than that of (127)I indicating the presence of a recalcitrant pool of (127)I that was unavailable for isotopic mixing.

  17. On the nature of humic substances

    NASA Astrophysics Data System (ADS)

    Fedotov, G. N.; Shoba, S. A.

    2015-12-01

    It is argued that the isolation of low-molecular-weight compounds from humic substances does not prove their supramolecular nature, because small molecules can be sorbed on macromolecules by interacting with them due to noncovalent bonds. The relative mobility of molecular segments in humic substances has been proposed to be used as a criterion for the discrimination between the humic substances of supraand macromolecular nature. The macromolecules are characterized by mobility of their segments, whereas supramolecular systems have stiff structure. This difference between macroand supramolecules results in different behaviors of the matrices (gels) formed from them in the processes of segregation. In the macromolecules, the formations of a new phase appearing at the segregation (microphase separation) are of nano size, at least in one dimension. They are incapable of moving within the matrix and form a well-known, limited set of systems. In the supramolecular matrices, the new-phase formations should have higher mobility and ability to move within the matrix with the formation of particles and zones of not only nano, but also micro sizes, as well as a significantly larger set of systems, including fractal configurations. The experimental electron microscopic study of the humic matrices of soil gels shows that the new-phase formations in the matrix of humic substances have not only nano, but also micro sizes and are capable of moving within the matrix, which confirms the supramolecular nature of humic substances. The proposed method has allowed generalizing the supraand macromolecular approaches, because macromolecules can enter into the composition of supramolecular systems. It is no less important that the behavior of HSs can be perceived as the behavior of stiff impenetrable particles that may compose the structures of different types and sizes.

  18. Numerical taxonomy of phenanthrene-degrading bacteria isolated from the Chesapeake Bay.

    PubMed Central

    West, P A; Okpokwasili, G C; Brayton, P R; Grimes, D J; Colwell, R R

    1984-01-01

    Phenanthrene-degrading bacteria were isolated from Chesapeake Bay samples by the use of a solid medium which had been overlaid with an ethanol solution of phenanthrene before inoculation. Eighteen representative strains of phenanthrene-degrading bacteria with 21 type and reference bacteria were examined for 123 characteristics representing physiological, biochemical, and nutritional properties. Relationships between strains were computed with several similarity coefficients. The phenogram constructed by unweighted-pair-group arithmetic average linkage and use of the simple Jaccard (SJ) coefficient was used to identify seven phena. Phenanthrene-degrading bacteria were identified as Vibrio parahaemolyticus and Vibrio fluvialis by their clustering with type and reference strains. Several phenanthrene-degrading bacteria resembled Enterobacteriaceae family members, although some Vibrio-like phenanthrene degraders could not be identified. PMID:6508314

  19. Numerical taxonomy of phenanthrene-degrading bacteria isolated from the Chesapeake Bay

    SciTech Connect

    West, P.A.; Okpokwasili, G.C.; Brayton, P.R.; Grimes, D.J.; Colwell, R.R.

    1984-11-01

    Phenanthrene-degrading bacteria were isolated from Chesapeake Bay samples by the use of a solid medium which had been overlaid with an ethanol solution of phenanthrene before inoculation. Eighteen representative strains of phenanthrene-degrading bacteria with 21 type and reference bacteria were examined for 123 characteristics representing physiological, biochemical, and nutritional properties. Relationships between strains were computed with several similarity coefficients. The phenogram constructed by unweighted-pair-group arithmetic average linkage and use of the simple Jaccard (S/sub J/) coefficient was used to identify seven phena. Phenanthrene-degrading bacteria were identified as Vibrio parahaemolyticus and Vibrio fluvialis by their clustering with type and reference strains. Several phenanthrene-degrading bacteria resembled Enterobacteriaceae family members, although some Vibrio-like phenanthrene degraders could not be identified. 22 references, 1 figure, 2 tables.

  20. Characterising the exchangeability of phenanthrene associated with naturally occurring soil colloids using an isotopic dilution technique.

    PubMed

    Tavakkoli, Ehsan; Juhasz, Albert; Donner, Erica; Lombi, Enzo

    2015-04-01

    The association of polycyclic aromatic hydrocarbons (PAHs) with inorganic and organic colloids is an important factor influencing their bioavailability, mobility and degradation in the environment. Despite this, our understanding of the exchangeability and potential bioavailability of PAHs associated with colloids is limited. The objective of this study was to use phenanthrene as a model PAH compound and develop a technique using (14)C phenanthrene to quantify the isotopically exchangeable and non-exchangeable forms of phenanthrene in filtered soil water or sodium tetraborate extracts. The study was also designed to investigate the exchangeability of colloidal phenanthrene as a function of particle size. Our findings suggest that the exchangeability of phenanthrene in sodium tetraborate is controlled by both inorganic and organic colloids, while in aqueous solutions inorganic colloids play the dominant role (even though coating of these by organic matter cannot be excluded). Filter pore size did not have a significant effect on phenanthrene exchangeability.

  1. Infrared Absorption Spectrum of Matrix-Isolated Phenanthrene

    NASA Astrophysics Data System (ADS)

    Zhang, Xu; Stanley P. Sander

    2016-10-01

    The far-to-mid Infrared absorption spectrum of phenanthrene (C14H10), one of the polycyclic aromatic hydrocarbons (PAHs), has been measured in an argon matrix at 5 K. Thirty two fundamental bands for phenanthrene have been observed; one of them is detected for the first time (v54 = 1398.0 cm-1) and eight of them are detected for the first time at temperatures below room temperature (v43 = 233.8 cm-1, v42 = 425.2 cm-1, v66 = 441.6 cm-1, v65 = 499.0 cm-1, v21 = 546.3 cm-1, v63 = 714.5 cm-1, v18 = 1033.7 cm-1 and v55 = 1362.5 cm-1). The relative intensities of these 32 bands have been measured; three ( v21, v18, v54) of which are measured for the first time and six ( v43, v42, v66, v65, v63, and v55) of which are measured for the first time at temperatures below room temperature. Our low temperature study of the vibrational bands for phenanthrene provides important information for the spectral analysis of the Composite Infrared Spectrometer (CIRS) aboard the Cassini Spacecraft.

  2. Sublethal effects of phenanthrene, nicotine, and pinane on Daphnia pulex

    SciTech Connect

    Savino, J.F.; Tanabe, L.L. )

    1989-05-01

    Nearly 500 compounds were detected in the tissues of Great Lakes fish as compared to 8 in tissues of hatchery-reared fish. Lethal concentrations for many representative compounds were determined by testing their acute toxicity (48-hr EC50) to Daphnia pulex. However, the population growth and survival of aquatic organisms over longer time intervals are usually affected at concentrations much lower than the EC50 for a specific chemical. To develop a general relationship between acute and chronic concentrations for representative compounds detected in Great Lakes fish, the authors initiated full-life-cycle testing on D. pulex with phenanthrene, nicotine, and pinane. Growth and fecundity of daphnids was measured in 16-d tests in the laboratory. Phenanthrene and nicotine were highly toxic and pinane was moderately toxic to D. pulex in acute studies. For phenanthrene, a compound of the polycyclic aromatic hydrocarbons (PAHs) that has been associated with incomplete combustion of organic matter. For nicotine, a compound in the heterocyclic nitrogen class of chemicals that has been used as an insecticide, the EC50 was 0.24 mg/L. Cyclic alkanes, many of which are constituents of crude oil were represented by pinane for which the EC50 was 3.35 mg/L.

  3. Plasmid-mediated mineralization of naphthalene, phenanthrene, and anthracene.

    PubMed Central

    Sanseverino, J; Applegate, B M; King, J M; Sayler, G S

    1993-01-01

    The well-characterized plasmid-encoded naphthalene degradation pathway in Pseudomonas putida PpG7(NAH7) was used to investigate the role of the NAH plasmid-encoded pathway in mineralizing phenanthrene and anthracene. Three Pseudomonas strains, designated 5R, DFC49, and DFC50, were recovered from a polynuclear aromatic hydrocarbon-degrading inoculum developed from a manufactured gas plant soil slurry reactor. Plasmids pKA1, pKA2, and pKA3, approximately 100 kb in size, were isolated from these strains and characterized. These plasmids have homologous regions of upper and lower NAH7 plasmid catabolic genes. By conjugation experiments, these plasmids, including NAH7, have been shown to encode the genotype for mineralization of [9-14C]phenanthrene and [U-14C]anthracene, as well as [1-14C]naphthalene. One strain, Pseudomonas fluorescens 5RL, which has the complete lower pathway inactivated by transposon insertion in nahG, accumulated a metabolite from phenanthrene and anthracene degradation. This is the first direct evidence to indicate that the NAH plasmid-encoded catabolic genes are involved in degradation of polynuclear aromatic hydrocarbons other than naphthalene. Images PMID:8328809

  4. Induction of PAH degradation in a phenanthrene-degrading pseudomonad

    SciTech Connect

    Stringfellow, W.T.; Chen, S.H.; Aitken, M.D.

    1995-12-31

    Recent evidence suggests that different polycyclic aromatic hydrocarbon (PAH) substrates are metabolized by common enzymes in PAH-degrading bacteria, implying that inducers for low-molecular-weight PAH degradation may coinduce for the metabolism of higher-molecular-weight compounds. The authors have tested this hypothesis with a well-characterized PAH-degrading bacterium, Pseudomonas saccharophila P-15. Growth of P-15 on salicylate, a metabolite of phenanthrene degradation, and a known inducer for naphthalene degradation, induced the metabolism of both substrates. Several potential inducers were then tested for their effects on metabolism of the four-ring compounds pyrene and fluoranthene, neither of which is a growth substrate for P-15, but both of which can be metabolized by this organism. Incubation of P-15 in the presence of phenanthrene or salicylate induced the metabolism of pyrene and fluoranthene in resting-cell assays. Catechol, another intermediate of naphthalene and phenanthrene degradation, did not induce the metabolism of either compound and interfered with the inducing effect of salicylate. These results have implications for strategies designed to maintain PAH degradation in contaminated environments, particularly for compounds that are degraded slowly or are degraded only by nongrowth metabolism.

  5. Biostimulation as an attractive technique to reduce phenanthrene toxicity for meiofauna and bacteria in lagoon sediment.

    PubMed

    Louati, Hela; Said, Olfa Ben; Soltani, Amel; Got, Patrice; Cravo-Laureau, Cristiana; Duran, Robert; Aissa, Patricia; Pringault, Olivier; Mahmoudi, Ezzeddine

    2014-03-01

    A microcosm experiment was setup to examine (1) the effect of phenanthrene contamination on meiofauna and bacteria communities and (2) the effects of different bioremediation strategies on phenanthrene degradation and on the community structure of free-living marine nematodes. Sediments from Bizerte lagoon were contaminated with (100 mg kg(-1)) phenanthrene and effects were examined after 20 days. Biostimulation (addition of nitrogen and phosphorus fertilizer or mineral salt medium) and bioaugmentation (inoculation of a hydrocarbonoclastic bacterium) were used as bioremediation treatments. Bacterial biomass was estimated using flow cytometry. Meiofauna was counted and identified at the higher taxon level using a stereomicroscope. Nematodes, comprising approximately two thirds of total meiofauna abundance, were identified to genus or species. Phenanthrene contamination had a severe impact on bacteria and meiofauna abundances with a strong decrease of nematodes with a complete disappearance of polychaetes and copepods. Bioremediation counter balanced the toxic effects of phenanthrene since meiofauna and bacteria abundances were significantly higher (p < 0.01) than those observed in phenanthrene contamination. Up to 98 % of phenanthrene removal was observed. In response to phenanthrene contamination, the nematode species had different behavior: Daptonema fallax was eliminated in contaminated microcosms, suggesting that it is an intolerant species to phenanthrene; Neochromadora peocilosoma, Spirinia parasitifera, and Odontophora n. sp., which significantly (p < 0.05) increased in contaminated microcosms, could be considered as "opportunistic" species to phenanthrene whereas Anticoma acuminata and Calomicrolaimus honestus increased in the treatment combining biostimulation and bioaugmentation. Phenanthrene had a significant effect on meiofaunal and bacterial abundances (p < 0.05), with a strong reduction of density and change in the nematode communities

  6. Degradation of phenanthrene, fluorene, fluoranthene, and pyrene by a Mycobacterium sp.

    PubMed Central

    Boldrin, B; Tiehm, A; Fritzsche, C

    1993-01-01

    Mycobacterium sp. strain BB1 was isolated from a former coal gasification site. It was able to utilize phenanthrene, pyrene, and fluoranthene as sole sources of carbon and energy and to degrade fluorene cometabolically. Exponential growth with solid phenanthrene, pyrene, and fluoranthene was obtained in fermentor cultures. The growth rates were 0.069, 0.056, and 0.040 h-1, respectively. Several metabolites of phenanthrene and fluorene metabolism were identified. PMID:8328808

  7. Selection of nonionic surfactants in enhancing biodegradation of phenanthrene in soil

    SciTech Connect

    Jahan, K.; Ahmed, T.; Maier, W.J.

    1996-12-31

    This research addresses the influence of sub-cmc concentrations of selected commercial nonionic surfactants on the biodegradation of phenanthrene. Various types of nonionic surfactants were tested to determine their ability to enhance the availability of phenanthrene to microorganisms in soil systems. Nonionic surfactants were selected as they are known to have greater hydrocarbon solubilizing power, less toxicity to microbial populations and low foaming property. Surfactants were tested to measure their effectiveness for increasing solubility of phenanthrene, their sorption on the soil matrix, their biodegradability and also their effect on the sorption and biodegradation of phenanthrene. Batch and column studies were carried out for the biodegradation experiments. Batch isotherm experiments were conducted to characterize the sorption of surfactants and phenanthrene. Solubility enhancement of phenanthrene by the selected surfactants was mainly a micellar phenomena. Sorption of phenanthrene and the surfactants could be represented by the linear isotherm model. Sorption of phenanthrene was enhanced in the presence of surfactants. Batch and column biodegradation studies indicate that biodegradation of phenanthrene was enhanced in the presence of the surfactants. None of the surfactants were biodegraded during the timecourse of these experiments. This study indicates that surfactant selection for in-situ bioremediation of insoluble hydrocarbons will depend on a large number of factors with main emphasis on the hydrocarbon solubilizing power, low toxicity to Zn bacteria and the environment and low sorptive properties.

  8. Synthesis of the k-region monofluoro- and difluorobenzo(c)phenanthrenes

    SciTech Connect

    Mirsadeghi, S.; Whittaker, N. ); Thakker, D.R. ); Prasad, G.K.B.

    1989-06-23

    Polycyclic aromatic hydrocarbons are metabolically activated by cytochrome P-450 and epoxide hydrolase to ultimate mutagens and carcinogens. Substitution by fluorine at specific positions has been used to elucidate metabolic activation and detoxication pathways of polycyclic aromatic hydrocarbons. Substitution by fluorine at the K-region C-6 position of the weak carcinogen benzo(c)phenanthrene (1) causes a > 4-fold increase in its tumorigenicity. Out of the six possible monofluorobenzo(c)phenanthrenes, only 5-fluorobenzo(c)phenanthrene (8a) has not been evaluated as a carcinogen, presumably because a convenient synthetic method for the 5-fluoro derivative has not been available. Hence, a new method has been developed for the synthesis of 8a from readily available starting materials. The method consists of selective bromination of benzo(c)phenanthrene (1) to 5-bromobenzo(c)phenanthrene (3), substitution of bromine by an amino group, and a modified Schiemann reaction of 5-aminobenzo(c)phenanthrene (6a) to yield 5-fluorobenzo(c)phenanthrene (8a). An improved method for the synthesis of 6-fluorobenzo(c)phenanthrene (19) has also been developed which consists of bromofluorination of {beta}-naphthylstyrene, followed by selective dehydrobromination and photocyclization of the fluorostyrene to the 6-fluoro derivative 19. The above methods, with minor modifications, also provided synthetic routes for the preparation of the difluoro derivatives 5,7-, 5,8-, and 6,7-difluorobenzo(c)phenanthrenes.

  9. Effect of surfactants, dispersion and temperature on solubility and biodegradation of phenanthrene in aqueous media.

    PubMed

    Pantsyrnaya, T; Blanchard, F; Delaunay, S; Goergen, J L; Guédon, E; Guseva, E; Boudrant, J

    2011-03-01

    In the present study surfactant addition with the help of either a mechanical dispersion or a thermal treatment was applied in order to increase the solubility and the bioavailability of phenanthrene in aqueous media, and therefore to promote its biodegradation. Among four tested surfactants (Tween 80, Brij 30, sodium dodecyl sulphate and rhamnolipids), Brij 30 (0.5 gL(-1)) showed the best results allowing us to attain about 20 mgL(-1) of soluble phenanthrene. An additional thermal treatment at 60°C for 24h, 200 rpm permitted to increase the solubility of phenanthrene in the presence of Brij 30 (0.5 gL(-1)) to about 30 mgL(-1). Higher dispersions of phenanthrene particles as well as the reduction of their size were obtained using Ultra-Turrax and French press. The biodegradation of phenanthrene by Pseudomonas putida was then investigated. The reduction of size of phenanthrene particles by mechanical dispersion did not influence its biodegradation, suggesting that P. putida consumed only soluble phenanthrene. The addition of Brij 30 (0.5 gL(-1)) permitted to obtain more phenanthrene metabolized. The use of Brij 30 coupled with a transitory heating of phenanthrene-containing medium at 60°C led to an even more complete biodegradation. This might be a promising way to enhance biodegradation of PAHs.

  10. Comparison of water solubility enhancements of organic solutes by aquatic humic materials and commercial humic acids

    SciTech Connect

    Chiou, C.T.; Kile, D.E.; Brinton, T.I.; Malcolm, R.L.; Leenheer, J.A.; MacCarthy, P.

    1987-12-01

    Water solubility enhancements of 1,1-bis(p-chlorophenyl)-2,2,2-trichloroethane (p,p'-DDT), 2,4,5,2',5'-pentachlorobiphenyl (2,4,5,2',5'-PCB), and 2,4,4'-trichlorobiphenyl (2,4,4'-PCB) by dissolved organic matter have been studied with the following samples: (1) acidic water samples from the Suwannee River, Georgia, and the Sopchoppy River, Florida; (2) a humic extract of a nearly neutral pH water from the Calcasieu River, Louisiana; (3) commercial humic acids from the Aldrich Chemical Co. and Fluka-Tridom Chemical Corp. The calculated partition coefficients on a dissolved organic carbon basis (K/sub doc/) for organic solutes with water samples and aquatic humic extracts from this and earlier studies indicate that the enhancement effect varies with the molecular composition of the aquatic humic materials, The K/sub doc/ values with water and aquatic humic samples are, however, far less than the observed K/sub doc/ values obtained with the two commercial samples, by factors of about 4-20. In view of this finding, one should be cautious in interpreting the effects of the dissolved organic matter on solubility enhancement of organic solutes on the basis of the use of commercial humic acids. 14 references, 3 figures, 2 tables.

  11. Determination of polycyclic aromatic hydrocarbons by four-way parallel factor analysis in presence of humic acid

    NASA Astrophysics Data System (ADS)

    Yang, Ruifang; Zhao, Nanjing; Xiao, Xue; Yu, Shaohui; Liu, Jianguo; Liu, Wenqing

    2016-01-01

    There is not effective method to solve the quenching effect of quencher in fluorescence spectra measurement and recognition of polycyclic aromatic hydrocarbons in aquatic environment. In this work, a four-way dataset combined with four-way parallel factor analysis is used to identify and quantify polycyclic aromatic hydrocarbons in the presence of humic acid, a fluorescent quencher and an ubiquitous substance in aquatic system, through modeling the quenching effect of humic acid by decomposing the four-way dataset into four loading matrices corresponding to relative concentration, excitation spectra, emission spectra and fluorescence quantum yield, respectively. It is found that Phenanthrene, pyrene, anthracene and fluorene can be recognized simultaneously with the similarities all above 0.980 between resolved spectra and reference spectra. Moreover, the concentrations of them ranging from 0 to 8 μg L-1 in the test samples prepared with river water could also be predicted successfully with recovery rate of each polycyclic aromatic hydrocarbon between 100% and 120%, which were higher than those of three-way PARAFAC. These results demonstrate that the combination of four-way dataset with four-way parallel factor analysis could be a promising method to recognize the fluorescence spectra of polycyclic aromatic hydrocarbons in the presence of fluorescent quencher from both qualitative and quantitative perspective.

  12. Extractive biodegradation and bioavailability assessment of phenanthrene in the cloud point system by Sphingomonas polyaromaticivorans.

    PubMed

    Pan, Tao; Deng, Tao; Zeng, Xinying; Dong, Wei; Yu, Shuijing

    2016-01-01

    The biological treatment of polycyclic aromatic hydrocarbons is an important issue. Most microbes have limited practical applications because of the poor bioavailability of polycyclic aromatic hydrocarbons. In this study, the extractive biodegradation of phenanthrene by Sphingomonas polyaromaticivorans was conducted by introducing the cloud point system. The cloud point system is composed of a mixture of (40 g/L) Brij 30 and Tergitol TMN-3, which are nonionic surfactants, in equal proportions. After phenanthrene degradation, a higher wet cell weight and lower phenanthrene residue were obtained in the cloud point system than that in the control system. According to the results of high-performance liquid chromatography, the residual phenanthrene preferred to partition from the dilute phase into the coacervate phase. The concentration of residual phenanthrene in the dilute phase (below 0.001 mg/L) is lower than its solubility in water (1.18 mg/L) after extractive biodegradation. Therefore, dilute phase detoxification was achieved, thus indicating that the dilute phase could be discharged without causing phenanthrene pollution. Bioavailability was assessed by introducing the apparent logP in the cloud point system. Apparent logP decreased significantly, thus indicating that the bioavailability of phenanthrene increased remarkably in the system. This study provides a potential application of biological treatment in water and soil contaminated by phenanthrene.

  13. Evaluation of phenanthrene toxicity on earthworm (Eisenia fetida): an ecotoxicoproteomics approach.

    PubMed

    Wu, Shijin; Xu, Xian; Zhao, Shiliang; Shen, Feichao; Chen, Jianmeng

    2013-10-01

    The goal of this study was to identify promising new biomarkers of phenanthrene by identifying differentially expressed proteins in Eisenia fetida after exposure to phenanthrene. Extracts of earthworm epithelium collected at days 2, 7, 14, and 28 after phenanthrene exposure were analyzed by two dimensional electrophoresis (2-DE) and quantitative image analysis. Comparing the intensity of protein spots, 36 upregulated proteins and 45 downregulated proteins were found. Some of the downregulated and upregulated proteins were verified by MALDI-TOF/TOF-MS and database searching. Downregulated proteins in response to phenanthrene exposure were involved in glycolysis, energy metabolism, chaperones, proteolysis, protein folding and electron transport. In contrast, oxidation reduction, oxygen transport, defense systems response to pollutant, protein biosynthesis and fatty acid biosynthesis were upregulated in phenanthrene-treated E. fetida. In addition, ATP synthase b subunit, lysenin-related protein 2, lombricine kinase, glyceraldehyde 3-phosphate dehydrogenase, actinbinding protein, and extracellular globin-4 seem to be potential biomarkers since these biomarker were able to low levels (2.5 mg kg(-1)) of phenanthrene. Our study provides a functional profile of the phenanthrene-responsive proteins in earthworms. The variable levels and trends in these spots could play a potential role as novel biomarkers for monitoring the levels of phenanthrene contamination in soil ecosystems.

  14. Slow Desorption of Phenanthrene from Silica Particles: Influence of Pore Size, Pore Water, and Aging Time

    SciTech Connect

    Huesemann, Michael H.; Fortman, Timothy J.; Riley, Robert G.; Thompson, Christopher J.; Wang, Zheming; Truex, Michael J.; Peyton, Brent M.

    2006-01-16

    When micro-porous and meso-porous silica particles were exposed to aqueous phenanthrene solutions for various durations it was observed that sorbed-phase phenanthrene concentrations increased with aging time only for meso-porous but not micro-porous silicas. Desorption equilibrium was reached almost instantaneously for the micro-porous particles while both the rate and extent of desorption decreased with increasing aging time for the meso-porous silicas. These findings indicate that phenanthrene can be sequestered within the internal pore-space of meso-porous silicas while the internal surfaces of micro-porous silicas are not accessible to phenanthrene sorption, possibly due to the presence of physi- or chemi-sorbed water that may sterically hinder the diffusion of phenanthrene inside water-filled micro-pores. By contrast, the internal surfaces of these micro-porous silicas are accessible to phenanthrene when aging methods are employed which assure that pores are devoid of physi-sorbed water. Consequently, when phenanthrene was incorporated into these particles using either supercritical CO2 or via solvent soaking, the aqueous desorption kinetics were extremely slow indicating effective sequestration of phenanthrene inside micro-porous particles. Finally, a two-compartment conceptual model is used to interpret the experimental findings.

  15. Enhanced phenanthrene biodegradation in soil by slender oat root exudates and root debris.

    PubMed

    Miya, R K; Firestone, M K

    2001-01-01

    To investigate the mechanisms by which slender oat (Avena barbata Pott ex Link) enhances phenanthrene biodegradation, we analyzed the impacts of root exudates and root debris on phenanthrene biodegradation and degrader community dynamics. Accelerated phenanthrene biodegradation rates occurred in soils amended with slender oat root exudates as well as combined root debris + root exudate as compared with unamended controls. Root exudates significantly enhanced phenanthrene biodegradation in rhizosphere soils, either by increasing contaminant bioavailability and/or increasing microbial population size and activity. A modified most probable number (MPN) method was used to determine quantitative shifts in heterotrophic and phenanthrene degrader communities. During the first 4 to 6 d of treatment, heterotrophic populations increased in all amended soils. Both root debris-amended and exudate-amended soil then maintained larger phenanthrene degrader populations than in control soils later in the experiment after much of the phenanthrene had been utilized. Thus, root amendments had a greater impact over time on phenanthrene degraders than heterotrophs resulting in selective maintenance of degrader populations in amended soils compared with controls.

  16. Estimation of direct-contact fraction for phenanthrene in surfactant solutions by toxicity measurement.

    PubMed

    Lee, Hyo J; Lee, Min W; Lee, Dae S; Woo, Seung H; Park, Jong M

    2007-09-30

    The toxicity of solutions containing nonionic surfactants Tween 80, Brij 35 and/or phenanthrene to Pseudomonas putida ATCC 17484 was investigated. The fraction of direct contact between micellar-phase phenanthrene and bacterial cell surface was estimated by using the toxicity data and a mathematical model. The mathematical model was used to calculate phenanthrene concentration in the micellar phase and aqueous pseudophase separately. The first-order death rate constant increased from 0.088+/-0.016 to 0.25+/-0.067 h(-1) when the phenanthrene concentration was increased from 0 to 5.17 x 10(-6)M (equals water solubility). The intrinsic toxicity of surfactant was higher in Brij 35 than in Tween 80. When phenanthrene concentration was increased to 9.7 x 10(-5)M in surfactant solutions, the death rate constant increased to 1.8 +/- 0.024 and 0.41 +/- 0.088 h(-1) for 8.4 x 10(-4)M Brij 35 and 7.6 x 10(-4)M Tween 80. The direct-contact fraction was 0.083 and 0.044 for Brij 35 and Tween 80, respectively, under these conditions using exponential model. The toxicity increased with increasing phenanthrene concentration at a fixed surfactant concentration. The toxicity decreased with increasing the surfactant concentration at a fixed phenanthrene concentration due to decreased contact of bacteria with phenanthrene present in the interior of surfactant micelles.

  17. Physiological and molecular responses of springtails exposed to phenanthrene and drought.

    PubMed

    Holmstrup, Martin; Slotsbo, Stine; Schmidt, Stine N; Mayer, Philipp; Damgaard, Christian; Sørensen, Jesper G

    2014-01-01

    Interaction between effects of hazardous chemicals in the environment and adverse climatic conditions is a problem that receives increased attention in the light of climate change. We studied interactive effects of phenanthrene and drought using a test system in which springtails (Folsomia candida Willem) were concurrently exposed to a sublethal phenanthrene level via passive dosing from silicone (chemical activity of 0.010), and sublethal drought from aqueous NaCl solutions (water activity of 0.988). Previous studies have shown that the combined effects of high levels of phenanthrene and drought, respectively, interact synergistically when using lethality as an end-point. Here, we hypothesized that phenanthrene interferes with physiological mechanisms involved in drought tolerance, and that drought influences detoxification of phenanthrene. However, this hypothesis was not supported by data since phenanthrene had no effect on drought-protective accumulation of myo-inositol, and normal water conserving mechanisms of F. candida were functioning despite the near-lethal concentrations of the toxicant. Further, detoxifying induction of cytochrome P450 and glutathione-S-transferase was not impeded by drought. Both phenanthrene and drought induced transcription of heat shock protein (hsp70) and the combined effect of the two stressors on hsp70 transcription was additive, suggesting that the cellular stress and lethality imposed by these levels of phenanthrene and drought were also additive.

  18. Pulmonary surfactant suppressed phenanthrene adsorption on carbon nanotubes through solubilization and competition as examined by passive dosing technique.

    PubMed

    Zhao, Jian; Wang, Zhenyu; Mashayekhi, Hamid; Mayer, Philipp; Chefetz, Benny; Xing, Baoshan

    2012-05-15

    Adsorption of phenanthrene on carbon nanotubes (CNTs) was examined in the presence of pulmonary surfactant (Curosurf) and its main components, dipalmitoyl phosphatidylcholine (DPPC) and bovine serum albumin (BSA). A passive-dosing method based on equilibrium partitioning from a preloaded polymer was successfully employed to measure phenanthrene binding and speciation at controlled freely dissolved concentrations while avoiding phase separation steps. Curosurf, DPPC, and BSA could all linearly solubilize phenanthrene, and phenanthrene solubilization by Curosurf was 4 times higher than individual components (DPPC or BSA). In the presence of Curosurf, DPPC or BSA, adsorption of phenanthrene by multiwalled CNTs (MWCNTs) was suppressed, showing competitive adsorption between pulmonary surfactant (or DPPC, BSA) and phenanthrene. Competitive adsorption between Curosurf and phenanthrene was the strongest. Therefore, when phenanthrene-adsorbed CNTs enter the respiratory tract, phenanthrene can be desorbed due to both solubilization and competition. The bioaccessibility of phenanthrene adsorbed on three MWCNTs in the respiratory tract would be positively related to the size of their outer diameters. Moreover, the contribution of solubilization and competition to desorption of phenanthrene from MWCNTs was successfully separated for the first time. These findings demonstrate the two mechanisms on how pulmonary surfactants can enhance desorption and thus possibly biological absorption of phenanthrene adsorbed on CNTs.

  19. Removal of phenanthrene in contaminated soil by combination of alfalfa, white-rot fungus, and earthworms.

    PubMed

    Deng, Shuguang; Zeng, Defang

    2017-01-23

    The aim of this study was to investigate the removal of phenanthrene by combination of alfalfa, white-rot fungus, and earthworms in soil. A 60-day experiment was conducted. Inoculation with earthworms and/or white-rot fungus increased alfalfa biomass and phenanthrene accumulation in alfalfa. However, inoculations of alfalfa and white-rot fungus can significantly decrease the accumulation of phenanthrene in earthworms. The removal rates for phenanthrene in soil were 33, 48, 66, 74, 85, and 93% under treatments control, only earthworms, only alfalfa, earthworms + alfalfa, alfalfa + white-rot fungus, and alfalfa + earthworms + white-rot fungus, respectively. The present study demonstrated that the combination of alfalfa, earthworms, and white-rot fungus is an effective way to remove phenanthrene in the soil. The removal is mainly via stimulating both microbial development and soil enzyme activity.

  20. Effect of root exudates on sorption, desorption, and transport of phenanthrene in mangrove sediments.

    PubMed

    Jia, Hui; Lu, Haoliang; Dai, Minyue; Hong, Hualong; Liu, Jingchun; Yan, Chongling

    2016-08-15

    The effect of root exudates on the environmental behaviors of phenanthrene in mangrove sediments is poorly understood. In order to evaluate their influence, comprehensive laboratory experiments were performed using batch equilibrium and thin-layer chromatography (TLC) analyses. In the presence of root exudates, sorption of phenanthrene was inhibited, whereas desorption and mobility were promoted, and were elevated as root exudate concentrations increased. Among the three representative low molecular weight organic acids (LMWOAs) (citric, oxalic, and acetic acids), citric acid promoted desorption and mobility of phenanthrene more effectively than the other two. In addition, application of artificial root exudates (AREs) enhanced phenanthrene desorption, and mobility was always lower than that with the same concentration of LMWOAs, suggesting that LMWOAs predominantly affected the fate of phenanthrene in sediments. The results of this study could enhance our understanding of the mobility of persistent organic pollutants in sediment-water system.

  1. Solubilization of phenanthrene above cloud point of Brij 30: a new application in biodegradation.

    PubMed

    Pantsyrnaya, T; Delaunay, S; Goergen, J L; Guseva, E; Boudrant, J

    2013-06-01

    In the present study a new application of solubilization of phenanthrene above cloud point of Brij 30 in biodegradation was developed. It was shown that a temporal solubilization of phenanthrene above cloud point of Brij 30 (5wt%) permitted to obtain a stable increase of the solubility of phenanthrene even when the temperature was decreased to culture conditions of used microorganism Pseudomonas putida (28°C). A higher initial concentration of soluble phenanthrene was obtained after the cloud point treatment: 200 against 120μM without treatment. All soluble phenanthrene was metabolized and a higher final concentration of its major metabolite - 1-hydroxy-2-naphthoic acid - (160 against 85μM) was measured in the culture medium in the case of a preliminary cloud point treatment. Therefore a temporary solubilization at cloud point might have a perspective application in the enhancement of biodegradation of polycyclic aromatic hydrocarbons.

  2. Effect of humic acid on sorption of technetium by alumina.

    PubMed

    Kumar, S; Rawat, N; Kar, A S; Tomar, B S; Manchanda, V K

    2011-09-15

    Sorption of technetium by alumina has been studied in absence as well as in presence of humic acid using (95)Tc(m) as a tracer. Measurements were carried out at fixed ionic strength (0.1M NaClO(4)) under varying pH (3-10) as well as redox (aerobic and reducing anaerobic) conditions. Under aerobic conditions, negligible sorption of technetium was observed onto alumina both in absence and in presence of humic acid. However, under reducing conditions (simulated with [Sn(II)] = 10(-6)M), presence of humic acid enhanced the sorption of technetium in the low pH region significantly and decreased at higher pH with respect to that in absence of humic acid. Linear additive as well as surface complexation modeling of Tc(IV) sorption in presence of humic acid indicated the predominant role of sorbed humic acid in deciding technetium sorption onto alumina.

  3. Interaction of Humic Acids with Organic Toxicants

    NASA Astrophysics Data System (ADS)

    Tchaikovskaya, O. N.; Yudina, N. V.; Maltseva, E. V.; Nechaev, L. V.; Svetlichnyi, V. A.

    2016-08-01

    Interaction of humic acids with polyaromatic hydrocarbons (PAH) (naphthalene and anthracene) and triazole series fungicides (cyproconazole (CC) and tebuconazole (TC)) is investigated by the method of fluorescence quenching depending on the concentration of substances in solutions and their structural features. Humic acids were modified by mechanochemical activation in a planetary mill. The complex character of intermolecular interactions between PAH and fungicides with humic acids, including donor-acceptor and hydrophobic binding, is established. Thermodynamically stable conformations of biocide molecules were estimated using ChemOffice CS Chem3D 8.0 by methods of molecular mechanics (MM2) and molecular dynamics. Biocide molecules with pH 7 are in energetically favorable position when the benzene and triazole rings are almost parallel to each other. After acidification of solutions to pH 4.5, the CC molecule retains the geometry for which donor-acceptor interactions are possible: the benzene ring in the molecule represents the electron donor, and triazole is the acceptor. In this case, the electron density in CC is redistributed easier, which is explained by a smaller number of carbon atoms between the triazole and benzene rings, unlike TC. As a result, the TC triazole ring is protonated to a greater degree, acquiring a positive charge, and enters into donoracceptor interactions with humic acid (HA) samples. The above-indicated bond types allow HA to participate actively in sorption processes and to provide their interaction with biocides and PAH and hence, to act as detoxifying agents for recultivation of the polluted environment.

  4. Adsorption and bioaccessibility of phenanthrene on carbon nanotubes in the in vitro gastrointestinal system.

    PubMed

    Li, Wei; Zhao, Jian; Zhao, Qing; Zheng, Hao; Du, Peng; Tao, Shu; Xing, Baoshan

    2016-10-01

    Adsorption and bioaccessibility of phenanthrene on graphite and multiwalled carbon nanotubes (CNTs) were investigated in simulated gastrointestinal fluid using a passive dosing system. The saturated adsorption capacity of phenanthrene on different adsorbents follows an order of hydroxylated CNTs (H-CNTs)>carboxylated CNTs (C-CNTs)>graphitized CNTs (G-CNTs)>graphite, consistent with the order of their surface area and micropore volume. The change of phenanthrene adsorption on the adsorbents is different with the presence of pepsin (800mg/L) and bile salts (500mg/L and 5000mg/L, abbreviated as BS500 and BS5000). Both solubilization of phenanthrene by pepsin and bile salts and their competition with phenanthrene for the adsorption sites play a role. In addition, the large increase of the maximum adsorption capacity in BS5000 solution indicates an enhanced dispersion of CNTs or an exfoliation of graphite by bile salts, which consequently increases the exposed surface area. The bioaccessibility increases in pepsin and BS500 solution with a growing free phenanthrene concentration. Although the bioaccessibility of phenanthrene stalls or slightly decreases in the middle range of free phenanthrene concentration in BS5000 solution, the bioaccessibility overall is much higher than that in pepsin and BS500 solution at the same phenanthrene level. It is impossible to separate the effect of competition from dispersion (or exfoliation) at this stage, but the relative contribution of solubilization to phenanthrene desorption in pepsin and BS500 solutions was quantified, which improves our understanding of the mechanisms on bioaccessibility of adsorbed pollutants on CNTs.

  5. Photochemical oxidation of phenanthrene sorbed on silica gel

    SciTech Connect

    Barbas, J.T.; Sigman, M.E.; Dabestani, R.

    1996-05-01

    There have been relatively few detailed studies of PAH photochemical degradation mechanisms and products at solid/air interfaces under controlled conditions. Results from mechanistic studies on particulate simulants are important in understanding the fates of PAH sorbed on similar materials in natural settings. In this study, the photolysis of phenanthrene (PH) on silica gel, in the presence of air, has been carefully examined. Once sorbed onto the silica surface, PH is not observed to repartition into the gas phase, even under vacuum, and dark reactions of PH are not observed at the silica/air interface. Photolysis (254 nm) of PH leads to the formation of 2,2`-biformylbiphenyl (1), 9,10-phenanthrenequinone (2), cis-9,10-dihydrodihydroxyphenanthrene (3), benzocoumarin (4), 2,2`-biphenyldicarboxylic acid (5), 2-formyl-2`-biphenylcarboxylic acid (6), 2-formylbiphenyl (7), 1,2-naphthalenedicarboxylic acid (8), and phthalic acid (9). These products account for 85-90% of the reacted PH. The photoproducts are independent of excitation wavelength (254 and 350 nm), and the reaction proceeds entirely through an initial step involving the addition of singlet molecular oxygen to the ground state of phenanthrene with subsequent thermal and/or photochemical reactions of the initially formed product. 20 refs., 3 figs., 1 tab.

  6. Thermodynamics and existing phase of Ba-phenanthrene

    NASA Astrophysics Data System (ADS)

    Heguri, Satoshi; Thi Nhu Phan, Quynh; Tanabe, Yoichi; Tanigaki, Katsumi

    2015-03-01

    The recent discovery of superconductivity in potassium doped picene suggested the possibility of a new class of superconductors. The problem is that no satisfactory guide to improve the superconducting shielding fraction had been provided until recently. However, a high superconducting shielding fraction of 65 % was reported for Ba1.5(phenanthrene). Considering this situation, phenanthrene (PHN) appears to be a key material for confirming the existence of metallicity and superconductivity in the aromatic hydrocarbon (AHC) family, and also for clarifying the physical properties and superconducting mechanism of AHC superconductors. In the present work, the thermodynamics for intercalation of PHN with Ba is studied in comparison with its isomer of anthracene (AN). Contrarily to previous reports by other authors, the important observation that Ba is intercalated into neither PHN nor AN without affecting their molecular structures is unambiguously made by differential scanning calorimetry measurements and annealing time dependences observed by powder x-ray diffraction measurements. The reactions of Ba and PHN at elevated temperatures lead this system to molecular decomposition instead of intercalation. The phenomena of metallicity and superconductivity in PHN intercalated with alkaline earth metals (Ba or Sr) should be reconsidered.

  7. Biodegradation of phenanthrene and pyrene in compost-amended soil.

    PubMed

    Yuan, Shaw Y; Su, Lai M; Chang, Bea V

    2009-06-01

    This study investigated the biodegradation of the polycyclic aromatic hydrocarbons (PAHs) phenanthrene and pyrene in compost and compost-amended soil. The degradation rates of the two PAHs were phenanthrene>pyrene. The degradation of PAH was enhanced when the two PAHs were present simultaneously in the soil. The addition of either of the two types of compost (straw and animal manure) individually enhanced PAH degradation. Compost samples were separated into fractions with various particle size ranges, which spanned 2-50 microm, 50-105 microm, 105-500 microm, and 500-2000 microm. We observed that the compost fractions with smaller particle sizes demonstrated higher PAH degradation rates. However, when the different compost fractions were added to soil, compost particle size had no significant effect on the rate of PAH degradation. Of the micro-organisms isolated from the soil-compost mixtures, strains S1, S2, and S8, which were identified as Arthrobacter nicotianae, Pseudomonas fluorescens, and Bordetella Petrii, respectively, demonstrated the best degradation ability.

  8. Multisubstrate biodegradation kinetics of naphthalene, phenanthrene, and pyrene mixtures

    SciTech Connect

    Guha, S.; Peters, C.A.; Jaffe, P.R.

    1999-12-05

    Biodegradation kinetics of naphthalene, phenanthrene and pyrene were studied in sole-substrate systems, and in binary and ternary mixtures to examine substrate interactions. The experiments were conducted in aerobic batch aqueous systems inoculated with a mixed culture that had been isolated from soils contaminated with polycyclic aromatic hydrocarbons (PAHs). Monod kinetic parameters and yield coefficients for the individual parameters and yield coefficients for the individual compounds were estimated from substrate depletion and CO{sub 2} evolution rate data in sole-substrate experiments. In all three binary mixture experiments, biodegradation kinetics were comparable to the sole-substrate kinetics. In the ternary mixture, biodegradation of naphthalene was inhibited and the biodegradation rates of phenanthrene and pyrene were enhanced. A multisubstrate form of the Monod kinetic model was found to adequately predict substrate interactions in the binary and ternary mixtures using only the parameters derived from sole-substrate experiments. Numerical simulations of biomass growth kinetics explain the observed range of behaviors in PAH mixtures. In general, the biodegradation rates of the more degradable and abundant compounds are reduced due to competitive inhibition, but enhanced biodegradation of the more recalcitrant PAHs occurs due to simultaneous biomass growth on multiple substrates. In PAH-contaminated environments, substrate interactions may be very large due to additive effects from the large number of compounds present.

  9. Antiallergic phenanthrenes and stilbenes from the tubers of Gymnadenia conopsea.

    PubMed

    Matsuda, Hisashi; Morikawa, Toshio; Xie, Haihui; Yoshikawa, Masayuki

    2004-09-01

    The methanolic extract from the tubers of Gymnadenia conopsea showed an antiallergic effect on ear passive cutaneous anaphylaxis reactions in mice. From the methanolic extract, three new dihydrophenanthrenes, gymconopins A ( 1), B ( 2), and C ( 3), and a new dihydrostilbene, gymconopin D ( 4), were isolated together with 10 known phenanthrene and stilbene constituents. The structures of the new compounds were determined on the basis of physicochemical evidence. Next, the inhibitory effects of the principal constituents on the release of beta-hexosaminidase, as a marker of degranulation, in RBL-2H3 cells were examined and five phenanthrenes, gymconopin B ( 2), 4-methoxy-9,10-dihydrophenanthrene-2,7-diol ( 6), 1-(4-hydroxybenzyl)-4-methoxyphenanthrene-2,7-diol ( 7), 1-(4-hydroxybenzyl)-4-methoxy-9,10-dihydrophenanthrene-2,7-diol ( 8), and blestriarene A ( 9), and six dihydrostilbenes, gymconopin D ( 4), batatacin III ( 10), 3'- O-methylbatatacin III ( 11), 3,3'-dihydroxy-2-(4-hydroxybenzyl)-5-methoxybibenzyl ( 12), 3',5-dihydroxy-2-(4-hydroxybenzyl)-3-methoxybibenzyl ( 13), and 3,3'-dihydroxy-2,6-bis(4-hydroxybenzyl)-5-methoxybibenzyl ( 14) were found to inhibit the antigen-induced degranulation by 65.5 to 99.4 % at 100 microM in RBL-2H3 cells.

  10. Antagonism of phenanthrene cytotoxicity for human embryo lung fibroblast cell line HFL-I by green tea polyphenols.

    PubMed

    Mei, Xin; Wu, Yuan-Yuan; Mao, Xiao; Tu, You-Ying

    2011-01-01

    Polycyclic aromatic hydrocarbons (PAHs) have been detected in some commercial teas around the world and pose a threat to tea consumers. However, green tea polyphenols (GTP) possess remarkable antioxidant and anticancer effects. In this study, the potential of GTP to block the toxicity of the model PAH phenanthrene was examined in human embryo lung fibroblast cell line HFL-I. Both GTP and phenanthrene treatment individually caused dose-dependent inhibition of cell growth. A full factorial design experiment demonstrated that the interaction of phenanthrene and GTP significantly reduced growth inhibition. Using the median effect method showed that phenanthrene and GTP were antagonistic when the inhibitory levels were less than about 50%. Apoptosis and cell cycle detection suggested that only phenanthrene affected cell cycle significantly and caused cell death; GTP lowered the mortality of HFL-I cells exposed to phenanthrene; However, GTP did not affect modulation of the cell cycle by phenanthrene.

  11. Transport of dissolved organic macromolecules and their effect on the transport of phenanthrene in porous media

    SciTech Connect

    Magee, B.R.; Lion, L.W.; Lemley, A.T. )

    1991-02-01

    The retardation factor (R) of phenanthrene in a sand column was reduced by an average factor of 1.8 in the presence of dissolved organic matter (DOM) derived from soil, suggesting that a phenanthrene-DOM complex enhanced the transport of phenanthrene. Distribution coefficients (K{sub d}'s) were determined in batch and column studies for combinations of phenanthrene and DOM with sand. The retardation factor in the advective-dispersive transport equation was modified to reflect the pressure of a carrier by incorporating both the retardation and pore exclusion of the carrier itself. The best prediction of phenanthrene transport in the presence of DOM was provided by modeling the retardation by using two K{sub d}'s derived from column experiments of DOM alone and phenanthrene alone, along with the K{sub d} for phenanthrene binding to DOM. Sensitivity analyses indicated that the critical model parameters are the distribution coefficients for the hydrophobic pollutant binding to the stationary phase and binding to the carrier, as well as the carrier concentration.

  12. Low impact of phenanthrene dissipation on the bacterial community in grassland soil.

    PubMed

    Niepceron, Maïté; Beguet, Jérémie; Portet-Koltalo, Florence; Martin-Laurent, Fabrice; Quillet, Laurent; Bodilis, Josselin

    2014-02-01

    The effect of phenanthrene on the bacterial community was studied on permanent grassland soil historically presenting low contamination (i.e. less than 1 mg kg(-1)) by polycyclic aromatic hydrocarbons (PAHs). Microcosms of soil were spiked with phenanthrene at 300 mg kg(-1). After 30 days of incubation, the phenanthrene concentration decreased rapidly until its total dissipation within 90 days. During this incubation period, significant changes of the total bacterial community diversity were observed, as assessed by automated-ribosomal intergenic spacer analysis fingerprinting. In order to get a deeper view of the effect of phenanthrene on the bacterial community, the abundances of ten phyla and classes (Actinobacteria, Acidobacteria, Bacteroidetes, Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Firmicutes, Verrucomicrobiales, Gemmatimonadetes, and Planctomycetes) were monitored by quantitative polymerase chain reaction performed on soil DNA extracts. Interestingly, abundances of some bacterial taxa significantly changed as compared with controls. Moreover, among these bacterial groups impacted by phenanthrene spiking, some of them presented the potential of phenanthrene degradation, as assessed by PAH-ring hydroxylating dioxygenase (PAH-RHDα) gene detection. However, neither the abundance nor the diversity of the PAH-RHDα genes was significantly impacted by phenanthrene spiking, highlighting the low impact of this organic contaminant on the functional bacterial diversities in grassland soil.

  13. Oxidative stress and DNA damage responses to phenanthrene exposure in the estuarine guppy Poecilia vivipara.

    PubMed

    Machado, Anderson Abel de Souza; Hoff, Mariana Leivas Müller; Klein, Roberta Daniele; Cordeiro, Gilson Junior; Lencina Avila, Jannine Marquez; Costa, Patrícia Gomes; Bianchini, Adalto

    2014-07-01

    Despite ubiquitous phenanthrene contamination in aquatic coastal areas, little is known regarding its potential effects on estuarine fishes. The present work evaluated the response of a large suite of oxidative stress- and DNA damage-related biomarkers to phenanthrene exposure (10, 20 and 200 μg L(-1), 96 h) using DMSO as the solvent in estuarine guppy Poecilia vivipara (salinity 24 psu). Phenanthrene affected oxidative stress-related parameters, and decreased antioxidant defenses and reactive oxygen species in the gills and muscle overall. Lipid peroxidation occurred in muscle at 200 μg L(-1) phenanthrene. Genotoxicity was increased at 20 μg L(-1), while 200 μg L(-1) caused a relative decrease in erythrocyte release into the bloodstream. These findings indicated that phenanthrene is genotoxic and can induce oxidative stress, depending on tissue and phenanthrene concentration analyzed. Thus, some of the biomarkers analyzed in the present study are sufficiently sensitive to monitor the exposure of the guppy P. vivipara to phenanthrene in salt water. However, further studies are required for a better interpretation of the dose-response patterns observed.

  14. Phenanthrene mineralization along a natural salinity gradient in an Urban Estuary, Boston Harbor, Massachusetts

    SciTech Connect

    Shiaris, M.P. )

    1989-01-01

    The effect of varying salinity on phenanthrene and glutamate mineralization was examined in sediments along a natural salinity gradient in an urban tidal river. Mineralization was measured by trapping {sup 14}CO{sub 2} from sediment slurries dosed with trace levels of ({sup 14}C)phenanthrene or ({sup 14}C)glutamate. Sediments from three sites representing three salinity regimes (0, 15, and 30%) were mixed with filtered column water from each site. Ambient phenanthrene concentrations were also determined to calculate phenanthrene mineralization rates. Rates of phenanthrene mineralization related significantly to increasing salinity along the transect as determined by linear regression analysis. Rates ranged from 1 ng/hour/g dry sediment at the freshwater site to >16 ng/hour/g dry sediment at the 30% salinity site. Glutamate mineralization also increased from the fresh-water to the marine site; however, the relationship to salinity was not statistically significant. The results suggest that phenanthrene degraders in low salinity estuarine sediments subject to salt water intrusion are tolerant to a wide range of salinities buy phenanthrene degradation in brackish waters is mainly a function of obligate marine microorganisms.

  15. Response of uptake and translocation of phenanthrene to nitrogen form in lettuce and wheat seedlings.

    PubMed

    Zhan, Xinhua; Yuan, Jiahan; Yue, Le; Xu, Guohua; Hu, Bing; Xu, Renkou

    2015-04-01

    Polycyclic aromatic hydrocarbons (PAHs) are widespread chemicals that are potentially carcinogenic and toxic to human due to dietary intake of food crops contaminated by PAHs. To date, the mechanisms underlying root uptake and acropetal translocation of PAHs in crops are poorly understood. Here we describe uptake and translocation of phenanthrene (a model PAH) in relation to nitrogen form and concentration in wheat and lettuce seedlings. At concentrations of 0-15 mM, phenanthrene uptake by roots is enhanced with an increase in ammonium and inhibited with an increment of nitrate. Phenanthrene concentration in shoots is much lower than in roots, suggesting that the direction of phenanthrene transport is acropetal. Ammonium reduces both phenanthrene accumulation and bioconcentration factor in shoots, as well as translocation factor, but nitrate elevates them. Phenanthrene uptake increases nutrient solution pH in the treatments with either nitrate or ammonium. Thus, it is concluded that the root uptake and acropetal translocation of phenanthrene in crops are associated with nitrogen form. Our results provide both a novel insight into the mechanism on PAH transport in higher plants and a promising agronomic strategy to minimize PAH contamination in crops or to improve phytoremediation of PAH-contaminated soils or water via nitrogen management.

  16. Genetic determinants involved in the biodegradation of naphthalene and phenanthrene in Pseudomonas aeruginosa PAO1.

    PubMed

    Qi, Jing; Wang, Bobo; Li, Jing; Ning, Huanhuan; Wang, Yingjuan; Kong, Weina; Shen, Lixin

    2015-05-01

    Pseudomonas sp. are predominant isolates of degradation-competent strains while very few studies have explored the degradation-related genes and pathways in most of the degrading strains. P. aeruginosa PAO1 was found capable of degrading naphthalene and phenanthrene efficiently. In order to investigate the degradation-related genes of naphthalene and phenanthrene in P. aeruginosa PAO1, a random promoter library of about 5760 strains was constructed. Thirty-two clones for differentially expressed promoters were obtained by screening in the presence of sub-inhibitory concentration of naphthalene and phenanthrene. Among them, 13 genes were up-regulated and 15 were down-regulated in the presence of naphthalene as well as phenanthrene. The four remaining genes have different regulation tendencies by naphthalene or phenanthrene. By comparing the growth between the wild type and mutants as well as the complementations, the roles of seven selected up-regulated genes on naphthalene and phenanthrene degradation were investigated. Five of the seven selected up-regulated genes, like PA2666 and PA4780, were found playing key roles on the degradation in P. aeruginosa PAO1. Also, the results imply that these genes participate in the overlapping part of naphthalene and phenanthrene degradation pathways in PAO1. Results in the article offer the convenience quick method and platform for searching degradation-related genes. It also laid a foundation for understanding of the role of the regulated genes.

  17. Dynamics of microbial community during bioremediation of phenanthrene and chromium(VI)-contaminated soil microcosms.

    PubMed

    Ibarrolaza, Agustín; Coppotelli, Bibiana M; Del Panno, María T; Donati, Edgardo R; Morelli, Irma S

    2009-02-01

    The combined effect of phenanthrene and Cr(VI) on soil microbial activity, community composition and on the efficiency of bioremediation processes has been studied. Biometer flask systems and soil microcosm systems contaminated with 2,000 mg of phenanthrene per kg of dry soil and different Cr(VI) concentrations were investigated. Temperature, soil moisture and oxygen availability were controlled to support bioremediation. Cr(VI) inhibited the phenanthrene mineralization (CO(2) production) and cultivable PAH degrading bacteria at levels of 500-2,600 mg kg(-1). In the bioremediation experiments in soil microcosms the degradation of phenanthrene, the dehydrogenase activity and the increase in PAH degrading bacteria counts were retarded by the presence of Cr(VI) at all studied concentrations (25, 50 and 100 mg kg(-1)). These negative effects did not show a correlation with Cr(VI) concentration. Whereas the presence of Cr(VI) had a negative effect on the phenanthrene elimination rate, co-contamination with phenanthrene reduced the residual Cr(VI) concentration in the water exchangeable Cr(VI) fraction (WEF) in comparison with the soil microcosm contaminated only with Cr(VI). Clear differences were found between the denaturing gradient gel electrophoresis (DGGE) patterns of each soil microcosm, showing that the presence of different Cr(VI) concentrations did modulate the community response to phenanthrene and caused perdurable changes in the structure of the microbial soil community.

  18. Effects of nanoplastics and microplastics on toxicity, bioaccumulation, and environmental fate of phenanthrene in fresh water.

    PubMed

    Ma, Yini; Huang, Anna; Cao, Siqi; Sun, Feifei; Wang, Lianhong; Guo, Hongyan; Ji, Rong

    2016-12-01

    Contamination of fine plastic particles (FPs), including micrometer to millimeter plastics (MPs) and nanometer plastics (NPs), in the environment has caught great concerns. FPs are strong adsorbents for hydrophobic toxic pollutants and may affect their fate and toxicity in the environment; however, such information is still rare. We studied joint toxicity of FPs with phenanthrene to Daphnia magna and effects of FPs on the environmental fate and bioaccumulation of (14)C-phenanthrene in fresh water. Within the five sizes particles we tested (from 50 nm to 10 μm), 50-nm NPs showed significant toxicity and physical damage to D. magna. The joint toxicity of 50-nm NPs and phenanthrene to D. magna showed an additive effect. During a 14-days incubation, the presence of NPs significantly enhanced bioaccumulation of phenanthrene-derived residues in daphnid body and inhibited the dissipation and transformation of phenanthrene in the medium, while 10-μm MPs did not show significant effects on the bioaccumulation, dissipation, and transformation of phenanthrene. The differences may be attributed to higher adsorption of phenanthrene on 50-nm NPs than 10-μm MPs. Our findings underlined the high potential ecological risks of FPs, and suggested that NPs should be given more concerns, in terms of their interaction with hydrophobic pollutants in the environment.

  19. Characteristics of phenanthrene-degrading bacteria isolated from soils contaminated with polycyclic aromatic hydrocarbons.

    PubMed

    Aitken, M D; Stringfellow, W T; Nagel, R D; Kazunga, C; Chen, S H

    1998-08-01

    Ten bacterial strains were isolated from seven contaminated soils by enrichment with phenanthrene as the sole carbon source. These isolates and another phenanthrene-degrading strain were examined for various characteristics related to phenanthrene degradation and their ability to metabolize 12 other polycyclic aromatic hydrocarbons (PAH), ranging in size from two to five rings, after growth in the presence of phenanthrene. Fatty acid methyl ester analysis indicated that at least five genera (Agrobacterium, Bacillus, Burkholderia, Pseudomonas, and Sphingomonas) and at least three species of Pseudomonas were represented in this collection. All of the strains oxidized phenanthrene according to Michaelis-Menten kinetics, with half-saturation coefficients well below the aqueous solubility of phenanthrene in all cases. All but one of the strains oxidized 1-hydroxy-2-naphthoate following growth on phenanthrene, and all oxidized at least one downstream intermediate from either or both of the known phenanthrene degradation pathways. All of the isolates could metabolize (oxidize, mineralize, or remove from solution) a broad range of PAH, although the exact range and extent of metabolism for a given substrate were unique to the particular isolate. Benz[a]anthracene, chrysene, and benzo[a]pyrene were each mineralized by eight of the strains, while pyrene was not mineralized by any. Pyrene was, however, removed from solution by all of the isolates, and the presence of at least one significant metabolite from pyrene was observed by radiochromatography for the five strains in which such metabolites were sought. Our results support earlier indications that the mineralization of pyrene by bacteria may require unique metabolic capabilities that do not appear to overlap with the determinants for mineralization of phenanthrene or other high molecular weight PAH.

  20. A comparison of the accumulation of phenanthrene by marine amphipods in water versus sediment

    SciTech Connect

    Fusi, T.; Weber, L.J.

    1995-12-31

    The objective of this research is to compare the accumulation of the polycyclic aromatic hydrocarbon phenanthrene by marine amphipods from sediment and interstitial water versus from a water only exposure system. The equilibrium partitioning theory assumes that the exposure and response of benthic invertebrates are the same when exposed to the same contaminant concentration in water and interstitial water. In this series of experiments, three infaunal marine amphipod species; Eohaustorius estuarius (non tube-forming, burrowing amphipod), Leptocheirus plumulosus (burrow-building amphipod) and Grandidierella japonica (tube-building amphipod), were exposed to {sup 14}C-phenanthrene under three experimental conditions: (1) sediment spiked at a concentration resulting in an interstitial water concentration of 2.5 {micro}g/l phenanthrene; (2) sediment spiked at a concentration resulting in interstitial water concentration of 2.5 {micro}g/l and the overlying water spiked at 2.5 {micro}g/l phenanthrene; (3) a water only exposure with the water at a concentration of 2.5 {micro}g/l phenanthrene, The exposures were conducted in a static renewal system with the overlying and exposure water being replaced every 8 hours. The bioaccumulation of phenanthrene was followed over 72 hours. In all three species of amphipods, the accumulation of phenanthrene was significantly greater in the water only exposure than in the two sediment exposures. At 72 hours, the amphipod body burdens of phenanthrene in the water only exposures were, depending on the species, 7 to 24 times that of the sediment only exposures. The results suggest that water only exposures may overestimate sediment or interstitial exposure to phenanthrene and other nonionic, lipophilic compounds.

  1. Cysteine-β-cyclodextrin enhanced phytoremediation of soil co-contaminated with phenanthrene and lead.

    PubMed

    Wang, Guanghui; Wang, Yin; Hu, Suhang; Deng, Nansheng; Wu, Feng

    2015-07-01

    It is necessary to find an effective soil remediation technology for the simultaneous removal of hydrophobic organic contaminants and heavy metals from contaminated soils. In this work, a novel cysteine-β-cyclodextrin (CCD) was synthesized by the reaction of β-cyclodextrin with cysteine, and the structure of CCD was confirmed by (1)H-NMR, (13)C-NMR, FT-IR spectroscopy and elemental analysis. Pot-culture experiments were conducted to investigate the effects of CCD on the phytoremediation of soil co-contaminated with phenanthrene and lead. The results showed that CCD can enhance the phytoremediation of soil co-contaminated with phenanthrene and lead. When CCD was added to the co-contaminated soil, the concentrations of phenanthrene and Pb in roots and shoots of ryegrass (Lolium perenne L.) significantly increased, the presence of CCD is beneficial to the accumulation of phenanthrene and Pb in ryegrass, and the residual concentrations of phenanthrene and Pb in soils significantly decreased. Under the co-contamination of 500 mg Pb kg(-1) and 50 mg PHE kg(-1), the bioconcentration factor of phenanthrene and Pb in the presence of CCD was increased by 1.43-fold and 4.47-fold, respectively. After CCD was added to the contaminated soils, the residual concentration of phenanthrene and Pb in unplanted soil was decreased by 18 and 25%, respectively. However, for the planted soil, the residual concentration of phenanthrene and Pb was decreased by 48 and 56%, respectively. CCD may improve the bioavailability of phenanthrene and Pb in co-contaminated soil; CCD enhanced phytoremediation technology may be a good alternative for the removal of hydrophobic organic contaminants and heavy metals from contaminated soils.

  2. Utilizing surfactants to control the sorption, desorption, and biodegradation of phenanthrene in soil-water system.

    PubMed

    Jin, Haiwei; Zhou, Wenjun; Zhu, Lizhong

    2013-07-01

    An integrative technology including the surfactant enhanced sorption and subsequent desorption and biodegradation of phenanthrene in the soil-water system was introduced and tested. For slightly contaminated agricultural soils, cationic-nonionic mixed surfactant-enhanced sorption of organic contaminants onto soils could reduce their transfer to plants, therefore safe-guarding agricultural production. After planting, residual surfactants combined with added nonionic surfactant could also promote the desorption and biodegradation of residual phenanthrene, thus providing a cost-effective pollution remediation technology. Our results showed that the cationic-nonionic mixed surfactants dodecylpyridinium bromide (DDPB) and Triton X-100 (TX100) significantly enhanced soil retention of phenanthrene. The maximum sorption coefficient Kd of phenanthrene for contaminated soils treated by mixed surfactants was about 24.5 times that of soils without surfactant (Kd) and higher than the combined effects of DDPB and TX100 individually, which was about 16.7 and 1.5 times Kd, respectively. On the other hand, TX100 could effectively remove phenanthrene from contaminated soils treated by mixed surfactants, improving the bioavailability of organic pollutants. The desorption rates of phenanthrene from these treated soils were greater than 85% with TX100 concentration above 2000 mg/L and approached 100% with increasing TX100 concentration. The biodegradation rates of phenanthrene in the presence of surfactants reached over 95% in 30 days. The mixed surfactants promoted the biodegradation of phenanthrene to some extent in 10-22 days, and had no obvious impact on phenanthrene biodegradation at the end of the experiment. Results obtained from this study provide some insight for the production of safe agricultural products and a remediation scheme for soils slightly contaminated with organic pollutants.

  3. Impact of exotic and inherent dissolved organic matter on sorption of phenanthrene by soils.

    PubMed

    Gao, Yanzheng; Xiong, Wei; Ling, Wanting; Wang, Xiaorong; Li, Qiuling

    2007-02-09

    The impacts of exotic and inherent dissolved organic matter (DOM) on phenanthrene sorption by six zonal soils of China, chosen so as to have different soil organic carbon (SOC) contents, were investigated using a batch technique. The exotic DOM was extracted from straw waste. In all cases, the sorption of phenanthrene by soils could be well described by the linear equation. The presence of inherent DOM in soils was found to impede phenanthrene sorption, since the apparent distribution coefficients (K(d)(*)) for phenanthrene sorption by deionized water-eluted soils were 3.13-21.5% larger than the distribution coefficients (K(d)) by control soils. Moreover, the enhanced sorption of phenanthrene by eluted versus control soils was in positive correlation with SOC contents. On the other hand, it was observed that the influence of exotic DOM on phenanthrene sorption was related to DOM concentrations. The K(d)(*) values for sorption of phenanthrene in the presence of exotic DOM increased first and decreased thereafter with increasing the added DOM concentrations (0-106mgDOC/L). The K(d)(*) values at a low exotic DOM concentration (< or =28mgDOC/L) were 14.7-48.4% larger than their control K(d) values. In contrast, higher concentrations (> or =52mgDOC/L) of added exotic DOM clearly impeded the distribution of phenanthrene between soil and water. The effects of exotic and inherent DOM on phenanthrene sorption by soils may primarily be described as 'cumulative sorption', association of phenanthene with DOM in solution, and modified surface nature of soil solids due to DOM binding.

  4. Naturally occurring phenanthrene degrading bacteria associated with seeds of various plant species.

    PubMed

    Fernet, Jennifer L; Lawrence, John R; Germida, James J

    2016-01-01

    Seeds of 11 of 19 plant species tested yielded naturally occurring phenanthrene degrading bacteria when placed on phenanthrene impression plates. Seed associated phenanthrene degrading bacteria were mostly detected on caragana, Canada thistle, creeping red fescue, western wheatgrass, and tall wheat grass. Based on 16S rRNA analysis the most common bacteria isolated from these seeds were strains belonging to the genera Enterobacteria, Erwinia, Burkholderia, Pantoea, Pseudomonas, and Sphingomonas. These plants may provide an excellent source of pre-adapted bacterial-plant associations highly suitable for use in remediation of contaminated soil environments.

  5. Surface-active properties of humic and sulfochlorohumic acids

    SciTech Connect

    Ryabova, I.N.; Mustafina, G.A.; Akkulova, Z.G.; Satymbaeva, A.S.

    2009-10-15

    The surface tension of alkaline solutions of humic acids and their sulfochloroderivatives, which are synthesized by sulfonation of chlorohumic acids isolated from coal chlorinated by the electrochemical method, is investigated. It is established that humic compounds possess weak surface activity. Basic adsorption parameters are calculated.

  6. Effects of diaphragm discharge in water solutions containing humic substances

    NASA Astrophysics Data System (ADS)

    Halamova, Ivana; Stara, Zdenka; Krcma, Frantisek

    2010-01-01

    Preliminary results of research focused on the applications of DC diaphragm discharge in water solutions containing humic substances are presented in this paper. Diaphragm discharge investigated by this work was created in the reactor using constant DC high voltage up to 2 kV that gave the total input power from 100 to 200 W. Presented work investigated decomposition of humic substances by the electric discharge in the dependence of discharge conditions (electrode polarity) as well as solution properties (electrolyte kind, pH). Especially substantial effect of pH on humic acid decomposition has been observed when acidic conditions stimulated the degradation process. Absorption spectroscopy in UV-VIS region together with fluorescence spectroscopy has been used for the detection of changes in humic solutions. Index of humification was calculated from obtained fluorescence spectra and a significant decrease of aromatic components in the humic mixture was determined during the discharge treatment.

  7. Pyrrolidone - a new solvent for the methylation of humic acid

    USGS Publications Warehouse

    Wershaw, R. L.; Pinckney, D.J.; Booker, S.E.

    1975-01-01

    In the past, humic acid has been methylated by suspending it in a solution of diazomethane in diethyl ether, and degrading the partly methylated humic acid to release those parts of the molecule that were methylated. Only small fragments of the molecule have been identified by this technique. In the procedure described here the humic acid is dissolved in 2-pyrrolidone and methylated by the addition of diazomethane in diethyl ether and ethanol to the solution. Because the humic acid is completely dissolved in the reaction medium, disaggregation of the humic acid particles takes place and much more complete methylation is obtained. The methylated products may be fractionated by countercurrent distribution and analyzed by mass spectrometry.

  8. Effect of n-alkyl chain length on the complexation of phenanthrene and 9-alkyl-phenanthrene with $beta;-cyclodextrin

    NASA Astrophysics Data System (ADS)

    Rima, J.; Aoun, E.; Hanna, K.

    2004-06-01

    The characteristics of host-guest complexation between β-cyclodextrin (β-CD) and phenanthrene derivatives (phenanthrene, n-propyl, n-butyl and n-hexyl-phenanthrene) were investigated by fluorescence spectrometry. Linear and non-linear regression methods were used to estimate the formation constants ( K1). A 1:1 stoichiometric ratio and an effect of n-alkyl chain length on the formation constant were observed for the binary inclusion complex between guest and β-CD. The formation constant dramatically increases with the length of n-alkyl, it starts from the value of 140 l mol -1 for the phenanthrene to reach the value of 580 l mol -1 for hexyl-phenanthrene. The effect of the temperature on the fluorescence intensity of each complex (guest-host) was also studied; and then the thermodynamic parameters were calculated. The main inclusion site seems to be aromatic moiety for short chain molecules, and it moves toward the alkyl chain part, as the chain becomes longer.

  9. Infrared Spectra of Perdeuterated Naphthalene, Phenanthrene, Chrysene, and Pyrene

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.; Sandford, Scott A.; Hudgins, Douglas M.; Arnold, James O. (Technical Monitor)

    1996-01-01

    Calculations are carried out using density functional theory (DFT) to determine the harmonic frequencies and intensities of perdeuterated naphthalene, phenanthrene, pyrene, and chrysene. We also report matrix- isolation spectra for these four species. The theoretical and experimental frequencies and relative intensities for the perdeuterated species are in generally good agreement. The effect of perdeuteration is to reduce the sum of the integrated intensities by a factor of about 1.75. This reduction occurs for all vibrational motions, except for the weak low frequency ring deformation modes. There is also a significant redistribution of the relative intensities between the out-of-plane C-D bands relative to those found for the out-of-plane C-H bands. The theoretical isotopic ratios provide an excellent diagnostic of the degree of C-H(C-D) involvement in the vibrational bands, allowing in most cases a clear distinction of the type of motion.

  10. Drift mobility of holes in phenanthrene single crystals

    NASA Technical Reports Server (NTRS)

    Sonnonstine, T. J.; Hermann, A. M.

    1974-01-01

    The temperature dependence of drift mobilities of holes in single crystals of phenanthrene was measured in the range from 203 to 353 K in three crystallographic directions. Below the anomaly temperature of 72 C, the mobility temperature dependences are consistent with the Munn and Siebrand slow-phonon hopping process in the b direction and the Munn and Siebrand slow-phonon coherent mode in the a and c prime directions. The drift mobility temperature dependences in crystals that have been cooled through the anomaly temperature in the presence of illumination and an electric field are consistent with the model of Spielberg et al. (1971), in which the hindered vibration of the 4,5 hydrogens introduces a new degree of freedom above 72 C.

  11. Thermodynamics and existing phase of Ba-phenanthrene

    NASA Astrophysics Data System (ADS)

    Heguri, Satoshi; Thi Nhu Phan, Quynh; Tanabe, Yoichi; Tanigaki, Katsumi

    2014-10-01

    The thermodynaqmics for intercalation of phenanthrene (PHN) with Ba, for which superconductivity has been reported, is studied in comparison with its isomer of a linear aromatic hydrocarbon of anthracene (AN). Contrary to previous reports by other authors, the important observation that Ba is intercalated into neither PHN nor AN without affecting their molecular structures is unambiguously made by differential scanning calorimetry measurements and annealing time dependences observed by powder x-ray diffraction (XRD) measurements. The reactions of Ba and PHN at elevated temperatures lead this system to molecular decomposition instead of intercalation, resulting in the Ba C2 carbide or amorphous carbon formation, which is clearly supported by XRD and Raman spectroscopy. The phenomena of metallicity and superconductivity in PHN intercalated with alkaline-earth metals (Ba or Sr) should be reconsidered.

  12. Humic substances as a mediator for microbially catalyzed metal reduction

    USGS Publications Warehouse

    Lovley, D.R.; Fraga, J.L.; Blunt-Harris, E. L.; Hayes, L.A.; Phillips, E.J.P.; Coates, J.D.

    1998-01-01

    The potential for humic substances to serve as a terminal electron acceptor in microbial respiration and to function as an electron shuttle between Fe(III)-reducing microorganisms and insoluble Fe(III) oxides was investigated. The Fe(III)-reducing microorganism Geobacter metallireducens conserved energy to support growth from electron transport to humics as evidenced by continued oxidation of acetate to carbon dioxide after as many as nine transfers in a medium with acetate as the electron donor and soil humic acids as the electron acceptor. Growth of G. metallireducens with poorly crystalline Fe(III) oxide as the electron acceptor was greatly stimulated by the addition of as little as 100 ??M of the humics analog, anthraquinone-2,6-disulfonate. Other quinones investigated, including lawsone, menadione, and anthraquinone-2-sulfonate, also stimulated Fe(III) oxide reduction. A wide phylogenetic diversity of microorganisms capable of Fe(III) reduction were also able to transfer electrons to humics. Microorganisms which can not reduce Fe(III) could not reduce humics. Humics stimulated the reduction of structural Fe(III) in clay and the crystalline Fe(III) forms, goethite and hematite. These results demonstrate that electron shuttling between Fe(III)-reducing microorganisms and Fe(III) via humics not only accelerates the microbial reduction of poorly crystalline Fe(III) oxide, but also can facilitate the reduction of Fe(III) forms that are not typically reduced by microorganisms in the absence of humics. Addition of humic substances to enhance electron shuttling between Fe(III)-reducing microorganisms and Fe(III) oxides may be a useful strategy to stimulate the remediation of soils and sediments contaminated with organic or metal pollutants.

  13. Sources of sedimentary humic substances: vascular plant debris

    NASA Astrophysics Data System (ADS)

    Ertel, John R.; Hedges, John I.

    1985-10-01

    A modern Washington continental shelf sediment was fractionated densimetrically using either an organic solvent, CBrCl 3, or aqueous ZnCl 2. The resulting low density materials (<2.06 g/ml) account for only 1% of the sediment mass but contain 25% of the sedimentary organic carbon and 53% of the lignin. The C/N ratios (30-40) and lignin phenol yields ( Λ = 8) and compositions indicate that the low density materials are essentially pure vascular plant debris which is slightly enriched in woody ( versus nonwoody) tissues compared to the bulk sediment. The low density materials yield approximately one-third of their organic carbon as humic substances and contribute 23% and 14% of the total sedimentary humic and fulvic acids, respectively. Assuming that the lignin remaining in the sedimentary fraction is also contained in plant fragments that yield similar levels of humic substances, then 50% and 30% of the total humic and fulvic acids, respectively, arise directly from plant debris. Base-extraction of fresh and naturally degraded vascular plant materials reveals that significant levels of humic and fulvic acids are obtained using classical extraction techniques. Approximately 1-2% of the carbon from fresh woods and 10-25% from leaves and bark were isolated as humic acids and 2-4 times those levels as fulvic acids. A highly degraded hardwood yielded up to 44% of its carbon as humic and fulvic acids. The humic acids from fresh plants are generally enriched in lignin components relative to carbohydrates and recognizable biochemicals account for up to 50% of the total carbon. Humic and fulvic acids extracted directly from sedimentary plant debris could be responsible for a major fraction of the biochemical component of humic substances.

  14. Determination of phenanthrene bioavailability by using a self-dying reporter bacterium: test with model solids and soil.

    PubMed

    Shin, Doyun; Nam, Kyoungphile

    2012-02-20

    The present study was conducted to investigate the performance and feasibility of a self-dying reporter bacterium to visualize and quantify phenanthrene bioavailability in soil. The self-dying reporter bacterium was designed to die on the initiation of phenanthrene biodegradation. The viability of the reporter bacterium was determined by a fluorescence live/dead cell staining method and visualized by confocal laser scanning microscopic observation. Phenanthrene was spiked into four types of model solids and a sandy loam. The bioavailability of phenanthrene to the reporter bacterium was remarkably declined with the hydrophobicity of the model solids: essentially no phenanthrene was biodegraded in the presence of 9-nm pores and about 35.8% of initial phenanthrene was biodegraded without pores. Decrease in bioavailability was not evident in the nonporous hydrophilic bead, but a small decrease was observed in the porous hydrophilic bead at 1000 mg/kg of phenanthrene. The fluorescence intensity was commensurate with the extent of phenanthrene biodegradation by the reporter bacterium at the concentration range from 50 to 500 mg/kg. Such a quantitative relationship was also confirmed with a sandy loam spiked up to 1000 mg/kg of phenanthrene. This reporter bacterium may be a useful means to determine phenanthrene bioavailability in soil.

  15. Measuring the toxicity of alkyl-phenanthrenes to early life stages of medaka (Oryzias latipes) using partition-controlled delivery.

    PubMed

    Turcotte, Dominique; Akhtar, Parveen; Bowerman, Michelle; Kiparissis, Yiannis; Brown, R Stephen; Hodson, Peter V

    2011-02-01

    Alkyl-phenanthrenes are a class of compounds present in crude oil and toxic to developing fish. Most research on alkyl-phenanthrenes has focused on retene (7-isopropyl-1-methyl-phenanthrene), but little is known about the chronic toxicity of related congeners to the early life stages of fish. This project is the first to describe the chronic toxicity of a series of alkyl-phenanthrenes to the embryos of Japanese medaka (Oryzias latipes) using the partition-controlled delivery (PCD) method of exposure and is the first to establish a relationship between toxicity of alkyl-phenanthrenes and log P. With PCD, test concentrations were maintained by equilibrium partitioning of test chemicals from polydimethylsiloxane (PDMS) films containing various concentrations of C1 to C4 phenanthrenes. Log film:solution partition constants (log K(fs)) and aqueous solubility limits were determined for each alkyl-phenanthrene. The prevalence of abnormalities in fish embryos increased in an exposure-dependent manner, with median effective concentration (EC50) values lower than experimental solubility limits of the compounds, and typical of environmental concentrations. Alkyl-phenanthrenes were more toxic to medaka embryos than unsubstituted phenanthrene, with effects resembling those of dioxin and indicating a specific receptor-based mechanism of toxicity. These results extend conclusions for the Exxon Valdez oil spill, suggest a specific mechanism of toxicity for alkyl-phenanthrenes, and provide a model for assessing the risks of mixture toxicity.

  16. Effects of phenanthrene on the mortality, growth, and anti-oxidant system of earthworms (Eisenia fetida) under laboratory conditions.

    PubMed

    Wu, Shijin; Wu, Ermiao; Qiu, Lequan; Zhong, Weihong; Chen, Jianmeng

    2011-04-01

    To assess the toxic effects of phenanthrene on earthworms, we exposed Eisenia fetida to artificial soils supplemented with different concentrations (0.5, 2.5, 12.5, mgkg(-1) soil) of phenanthrene. The residual phenanthrene in the soil, the bioaccumulation of phenanthrene in earthworms, and the subsequent effects of phenanthrene on growth, anti-oxidant enzyme activities, and lipid peroxidation (LPO) were determined. The degradation rate of low concentrations of phenanthrene was faster than it was for higher concentrations, and the degradation half-life was 7.3d (0.5 mgkg(-1)). Bioaccumulation of phenanthrene in the earthworms decreased the phenanthrene concentration in soils, and phenanthrene content in the earthworms significantly increased with increasing initial soil concentrations. Phenanthrene had a significant effect on E. fetida growth, and the 14-d LC(50) was calculated as 40.67 mgkg(-1). Statistical analysis of the growth inhibition rate showed that the concentration and duration of exposure had significant effects on growth inhibition (p<0.001). Superoxide dismutase (SOD) activity increased at the beginning (2 and 7d) and decreased in the end (14 and 28 d). Catalase (CAT) activity in all treatments was inhibited from 1 to 14 d of exposure. However, no significant perturbations in malondialdehyde (MDA) content were noted between control and phenanthrene-treated earthworms except after 2d of exposure. These results revealed that bioaccumulation of phenanthrene in E. fetida caused concentration-dependent, sub-lethal toxicity. Growth and superoxide dismutase activity can be regarded as sensitive parameters for evaluating the toxicity of phenanthrene to earthworms.

  17. Sorption of phenanthrene and benzene on differently structural kerogen: important role of micropore-filling.

    PubMed

    Zhang, Yulong; Ma, Xiaoxuan; Ran, Yong

    2014-02-01

    Shale was thermally treated to obtain a series of kerogen with varied maturation. Their chemical, structural and porous properties were related to the sorption and/or desorption behaviors of phenanthrene and benzene. As the treatment temperature increases, aliphatic and carbonyl carbon of the kerogen samples decrease, while their aromaticity and maturation increase. Meanwhile, the isothermal nonlinearity of phenanthrene and benzene increases whereas the sorption capacity and micropore adsorption volumes (Vo,d) initially increase and then decrease. The Vo,d of benzene is significantly correlated with, but higher than that of phenanthrene, suggesting similar micropore filling mechanism and molecular sieve effect. The benzene desorption exhibits hysteresis, which is related to the pore deformation of the kerogen and the entrapment of solute in the kerogen matrix. The Vo,d of phenanthrene and benzene on the kerogen samples accounts for 23-46% and 36-65% of the maximum sorption volumes, respectively, displaying the importance of the micropore filling.

  18. Hydrocracking phenanthrene and 1-methyl naphthalene: Development of linear free energy relationships

    SciTech Connect

    Landau, R.N.; Korre, S.C.; Neurock, M.; Klein, M.T.; Quann, R.J.

    1994-12-31

    The catalytic hydrocracking reaction pathways, kinetics and mechanisms of 1-methyl naphthalene and phenanthrene were investigated in experiments at 350 C and 68.1 atm H{sub 2} partial pressure (190.6 atm total pressure), using a presulfided Ni/W on USY zeolite catalyst. 1-methyl naphthalene hydrocracking led to 2-methyl naphthalene, methyl tetralins, methyl decalins, pentyl benzene and tetralin. Phenanthrene hydrocracking led to dihydro, tetrahydro and octahydro phenanthrene, butyl naphthalene, tetralin to butyl tetralin and dibutyl benzene. The rate constants for the dealkylation of butyl tetralins produced in the phenanthrene hydrocracking network conform to a linear free energy relationship (LFER), with the heat of formation of the leaving alkyl carbenium ion as the reactivity index.

  19. Ab initio study of the optical properties of crystalline phenanthrene, including the excitonic effects

    NASA Astrophysics Data System (ADS)

    Dadsetani, Mehrdad; Nejatipour, Hajar; Ebrahimian, Ali

    2015-05-01

    Using the ab initio methods for solving the Bethe-Salpeter equation on the basis of the FPLAPW method, optical properties of crystalline phenanthrene were calculated, in a comparison to its isomer, anthracene. It was found that despite the similarity of the structural, electronic, and the overall optical properties in a 40 eV energy range, phenanthrene and anthracene show significant differences in their optical spectra in the energy range below band gaps. Phenanthrene has two spin singlet excitonic features whereas anthracene shows one. The singlet and the lowest triplet binding energies of phenanthrene were found to be larger than anthracene. In this study, in addition, a comparison has been made between the optical spectra in RPA and the existing experimental data.

  20. The impact of carbon nanomaterials on the development of phenanthrene catabolism in soil.

    PubMed

    Oyelami, Ayodeji O; Semple, Kirk T

    2015-07-01

    This study investigates the impact of different types of carbon nanomaterials (CNMs) namely C60, multi-walled carbon nanotubes (MWCNTs) and fullerene soot on the catabolism of (14)C-phenanthrene in soil by indigenous microorganisms. Different concentrations (0%, 0.01%, 0.1% and 1%) of the different CNMs were blended with soil spiked with 50 mg kg(-1) of (12)C-phenanthrene, and aged for 1, 25, 50 and 100 days. An increase in the concentration of MWCNT- and FS-amended soils showed a significant difference (P = 0.014) in the lag phase, maximum rates and overall extent of (14)C-phenanthrene mineralisation. Microbial cell numbers did not show an obvious trend, but it was observed that control soils had the highest population of heterotrophic and phenanthrene degrading bacteria at all time points.

  1. Effects of plant species identity, diversity and soil fertility on biodegradation of phenanthrene in soil.

    PubMed

    Oyelami, Ayodeji O; Okere, Uchechukwu V; Orwin, Kate H; De Deyn, Gerlinde B; Jones, Kevin C; Semple, Kirk T

    2013-02-01

    The work presented in this paper investigated the effects of plant species composition, species diversity and soil fertility on biodegradation of (14)C-phenanthrene in soil. The two soils used were of contrasting fertility, taken from long term unfertilised and fertilised grassland, showing differences in total nitrogen content (%N). Plant communities consisted of six different plant species: two grasses, two forbs, and two legume species, and ranged in species richness from 1 to 6. The degradation of (14)C-phenanthrene was evaluated by measuring indigenous catabolic activity following the addition of the contaminant to soil using respirometry. Soil fertility was a driving factor in all aspects of (14)C-phenanthrene degradation; lag phase, maximum rates and total extents of (14)C-phenanthrene mineralisation were higher in improved soils compared to unimproved soils. Plant identity had a significant effect on the lag phase and extents of mineralisation. Soil fertility was the major influence also on abundance of microbial communities.

  2. Monitoring plant response to phenanthrene using the red edge of canopy hyperspectral reflectance.

    PubMed

    Zhu, Linhai; Chen, Zhongxin; Wang, Jianjian; Ding, Jinzhi; Yu, Yunjiang; Li, Junsheng; Xiao, Nengwen; Jiang, Lianhe; Zheng, Yuanrun; Rimmington, Glyn M

    2014-09-15

    To investigate the mechanisms and potential for the remote sensing of phenanthrene-induced vegetation stress, we measured field canopy spectra, and associated plant and soil parameters in the field controlled experiment in the Yellow River Delta of China. Two widely distributed plant communities, separately dominated by reed (Phragmites australis) and glaucous seepweed (Suaeda salsa), were treated with different doses of phenanthrene. The canopy spectral changes of plant community resulted from the decreases of biomass and foliar projective coverage, while leaf photosynthetic pigment concentrations showed no significance difference among treatments. The spectral response to phenanthrene included a flattened red edge, with decreased first derivative of reflectance. The red edge slope and area consistently responded to phenanthrene, showing a strong relationship with aboveground biomass, coverage and canopy pigments density. These results suggest the potential of remote sensing and the importance of field validation to correctly interpret the causes of the spectral changes.

  3. Influence of surfactant sorption on the removal of phenanthrene from contaminated soils.

    PubMed

    Zhou, Wenjun; Zhu, Lizhong

    2008-03-01

    Laboratory column flushing experiments were conducted to remove phenanthrene from contaminated soils by Triton X-100 (TX100) with an aim to investigating the effect of surfactant sorption on the performance of surfactant-enhanced remediation process. The effluent concentration of phenanthrene from soil columns showed strong dependence on the sorption breakthrough curves of TX100. The removal of phenanthrene from contaminated soils was enhanced only when the sorption breakthrough of TX100 occurred and the influent concentration of TX100 was greater than the critical enhanced flushing concentration (CEFC). The sorption of surfactant onto soils and the subsequent partitioning of contaminants into soil-sorbed surfactant had a significant effect on the solute equilibrium distribution coefficient (KD) and thus the flushing efficiency for phenanthrene. A model was developed to predict KD and CEFC values for simulating the performance of surfactant-enhanced flushing for contaminated soils. These results are of practical interest in developing effective and safe surfactant-enhanced remediation technologies.

  4. Increase in bioavailability of aged phenanthrene in soils by competitive displacement with pyrene

    SciTech Connect

    White, J.C.; Hunter, M.; Pignatello, J.J.; Alexander, M.

    1999-08-01

    Competitive sorption to natural solids among mixtures of organic compounds has been documented in the literature. This study was conducted to determine co-solute competitive effects on the biological and physical availability of polycyclic aromatic hydrocarbons in soils after long contact periods (aging). Sterile suspensions of Mount Pleasant silt loam (Mt. Pleasant, NY, USA) and Pahokee peat soils were spiked with phenanthrene and allowed to age for 3 or 123 d before inoculation with a phenanthrene-degrading bacterium in the presence or absence of the nonbiodegradable co-solute pyrene. As expected, mineralization decreased with aging in the samples not amended with pyrene. However, addition of pyrene just prior to inoculation at 123 d significantly mitigated this decrease; that is, the extent of mineralization was greater in the 123-d pyrene-amended samples than in the 123-d nonamended samples. Parallel experiments on sterile soils showed that pyrene increased the physical availability of phenanthrene by competitive displacement of phenanthrene from sorption sites. First, the addition of pyrene increased recovery of 123-d-aged phenanthrene by mild solvent extraction. Second, addition of pyrene (at three concentrations) dramatically reduced the apparent distribution coefficient (K{sub d}{sup app}) of several concentrations of 60-, 95-, and 111-d-aged phenanthrene. At the lowest phenanthrene and highest pyrene concentrations, reductions in the K{sub d}{sup app} of phenanthrene in the peat soil reached 83%. The competitive displacement effect observed in this study adds further support to the dual mode model of sorption to soil organic matter. The displacement of an aged contaminant by a nonaged co-solute might also prove useful in the development of novel remediation strategies.

  5. Assessment of phenanthrene bioavailability in aged and unaged soils by mild extraction.

    PubMed

    Khan, Muhammad Imran; Cheema, Sardar Alam; Shen, Chaofeng; Zhang, Congkai; Tang, Xianjin; Shi, Jiyan; Chen, Xincai; Park, Joonhong; Chen, Yingxu

    2012-01-01

    It has become apparent that the threat of an organic pollutant in soil is directly related to its bioavailable fraction and that the use of total contaminant concentrations as a measure of potential contaminant exposure to plants or soil organisms is inappropriate. In light of this, non-exhaustive extraction techniques are being investigated to assess their appropriateness in determining bioavailability. To find a suitable and rapid extraction method to predict phenanthrene bioavailability, multiple extraction techniques (i.e., mild hydroxypropyl-β-cyclodextrin (HPCD) and organic solvents extraction) were investigated in soil spiked to a range of phenanthrene levels (i.e., 1.12, 8.52, 73, 136, and 335 μg g( - 1) dry soil). The bioaccumulation of phenanthrene in earthworm (Eisenia fetida) was used as the reference system for bioavailability. Correlation results for phenanthrene suggested that mild HPCD extraction was a better method to predict bioavailability of phenanthrene in soil compared with organic solvents extraction. Aged (i.e., 150 days) and fresh (i.e., 0 day) soil samples were used to evaluate the extraction efficiency and the effect of soil contact time on the availability of phenanthrene. The percentage of phenanthrene accumulated by earthworms and percent recoveries by mild extractants changed significantly with aging time. Thus, aging significantly reduced the earthworm uptake and chemical extractability of phenanthrene. In general, among organic extractants, methanol showed recoveries comparable to those of mild HPCD for both aged and unaged soil matrices. Hence, this extractant can be suitable after HPCD to evaluate risk of contaminated soils.

  6. Preparation and structure of ([mu]-phenanthrene)- and ([mu]-pyrene)bis(tricarbonylchromium)

    SciTech Connect

    Peitz, D.J.; Palmer, R.T.; Radonovich, L.J.; Woolsey, N.F. )

    1993-11-01

    The preparations of the bis(tricarbonylchromium) complexes of phenanthrene and pyrene are reported. These materials were characterized by spectroscopic means, including both their solution and solid CP/MAS NMR spectra. The X-ray crystal structure showed both complexes to have the anticipated anti orientation of the tricarbonylchromium moieties. In the phenanthrene complex, the rotomer conformations for the two tricarbonylchromium groups are different, whereas the pyrene complex has a center of inversion. 28 refs., 4 figs., 8 tabs.

  7. Fate of phenanthrene and mineralization of its non-extractable residues in an oxic soil.

    PubMed

    Wang, Yongfeng; Xu, Jun; Shan, Jun; Ma, Yini; Ji, Rong

    2017-05-01

    The fate of organic pollutants in the environment, especially the formation and stability of non-extractable (i.e., bound) residues (NERs) determines their environmental risk. Using (14)C-tracers, we studied the fate of the carcinogen phenanthrene in active or sterilized oxic loamy soil in the absence and presence of the geophagous earthworm Metaphire guillelmi and characterized the NERs derived from phenanthrene. After incubation of (14)C-phenanthrene in active soil for 28 days, 40 ± 3.1% of the initial amount was mineralized and 70.1 ± 1.9% was converted to NERs. Most of the NERs (>92%) were bound to soil humin. Silylation of the humin-bound residues released 45.3 ± 5.3% of these residues, which indicated that they were physically entrapped, whereas the remainder of the residues were chemically bound or biogenic. By contrast, in sterilized soil, only 43.4 ± 12.6% of the phenanthrene was converted to NERs and all of these residues were completely released upon silylation, which underlines the essential role of microbial activity in NER formation. The presence of M. guillelmi in active soil significantly inhibited phenanthrene mineralization (24.4 ± 2.6% mineralized), but NER formation was not significantly affected. Only a small amount of phenanthrene-derived residues (1.9-5.3% of the initial amount) accumulated in the earthworm body. When humin-bound residues were mixed with fresh soil, 33.9% (humin recovered from active soils) and 12.4% (humin recovered from sterilized soils) of the residues were mineralized after 75 days of incubation, respectively, which indicated a high bioavailability of NERs, albeit lower than the initial addition of phenanthrene. Our results indicated that many phenanthrene-derived NERs, especially those physically entrapped, are still bioavailable and may pose a toxic threat to soil organisms.

  8. Phenanthrene degradation in soil by ozonation: Effect of morphological and physicochemical properties.

    PubMed

    Rodriguez, J; García, A; Poznyak, T; Chairez, I

    2017-02-01

    The aim of this study was to characterize the ozone reaction with phenanthrene adsorbed in two types of soils (sand and agricultural). The effect of soil physicochemical properties (texture, bulk density, particle density, porosity, elemental composition, permeability, surface area and pore volume) on the phenanthrene decomposition was evaluated. Commercial sand has a uniform morphology (spherical) with a particle size range between 0.178 and 0.150 mm in diameter, regular elemental composition SiO2, specific density of 1701.38 kg/m(3), a true density of 2492.50 kg/m(3), with an effective porosity of 31%. On the other hand, the agricultural soil had heterogeneous morphology, particle size between 0.1779 and 0.05 mm in diameter, elemental composition was montmorrillonite silicon oxide, apparent density of 999.52 kg/m(3), a true density of 2673.55 kg/m(3), surface area of 34.92 m(2)/g and porosity of 57%. The percentage of phenanthrene decomposition in the sand was 79% after 2 h of treatment. On the other hand, the phenanthrene degradation in the agricultural soil was 95% during the same reaction time. The pore volume of soil limited the crystal size of phenanthrene and increased the contact surface with ozone confirming the direct impact of physicochemical properties of soils on the decomposition kinetics of phenanthrene. In the case of agricultural soil, the effect of organic matter on phenanthrene decomposition efficiency was also investigated. A faster decomposition of initial contaminant and byproducts formed in ozonation was obtained in natural agricultural soil compared to the sand. The partial identification of intermediates and final accumulated products produced by phenanthrene decomposition in ozonation was developed. Among others, phenanthroquinone, hydroquinone, phenanthrol, catechol as well as phthalic, diphenic, maleic and oxalic acids were identified.

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

    PubMed

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

    2011-03-01

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

  10. Phenanthrene-degrader community dynamics in rhizosphere soil from a common annual grass

    SciTech Connect

    Miya, R.K.; Firestone, M.K.

    2000-04-01

    Enhanced rates of phenanthrene biodegradation were observed in rhizosphere soils planted with slender oat (Avena barbata Pott ex Link) compared with unplanted bulk soil controls. Soil microbial populations were characterized using a modified most probable number (MPN) method to determine quantitative shifts in heterotrophic and phenanthrene degrader communities while principal component analysis (PCA) of fatty acid methyl ester (FAME) data from isolated phenanthrene degraders was used to identify qualitative differences and degrader community diversity. The average heterotrophic bacterial population over time was about three times larger in rhizosphere soil than in bulk soil while phenanthrene degrading populations increased by as much as an order of magnitude between 24 and 28 days after planting (DAP). Thus, phenanthrene degraders were selectively enriched in rhizosphere soil compared with bulk soil. The greatest selection for degraders occurred during the later stages of plant development from 24 to 32 DAP. A PCA plot of the FAME data from phenanthrene degrader isolates indicated that the rhizosphere degraders were less diverse than bulk soil degraders. These results give some insight into the mechanisms responsible for enhanced biodegradation and selective degrader enrichment in Rhizosphere soils.

  11. Effects of a nonionic surfactant on biodegradation of phenanthrene and hexadecane in soil

    SciTech Connect

    Macur, R.E.; Inskeep, W.P.

    1999-09-01

    The influence of a nonionic (alcohol ethoxylate) surfactant (Witconol SN70) on biodegradation of phenanthrene and hexadecane (nonaqueous-phase liquid) in soil was studied in batch and transport systems. Simultaneous enhancement of phenanthrene and hexadecane degradation was noted at surfactant doses resulting in aqueous-phase surfactant concentrations below the critical micelle concentration (CMC). Conversely, degradation rates of both compounds declined to essentially zero at supra-CMC doses, suggesting that distinct mechanisms of inhibition and enhancement were operating depending on the effective surfactant concentration. Surfactant doses resulting in enhanced degradation correlated with enhanced gross microbial activity as determined using total CO{sub 2} evolution rates. Supra-CMC does that resulted in inhibited degradation did not suppress gross microbial activity. Furthermore, measurements of phenanthrene solubilization and surface tension indicated that phenanthrene was solubilized at supra-CMC levels of surfactant. Mechanisms of inhibition of phenanthrene and hexadecane degradation at supra-CMC surfactant concentrations may include changes in interfacial chemistry and subsequent mass transfer processes due to sorbed surfactant, reduced bioavailability of micelle-bound phenanthrene and hexadecane, or inhibition of specific members of the microbial community responsible for hydrophobic organic compound degradation.

  12. A battery of bioassays for the evaluation of phenanthrene biotoxicity in soil.

    PubMed

    Khan, Muhammad Imran; Cheema, Sardar Alam; Tang, Xianjin; Hashmi, Muhammad Zaffar; Shen, Chaofeng; Park, Joonhong; Chen, Yingxu

    2013-07-01

    A battery of bioassays was used to assess the ecotoxicological risk of soil spiked with a range of phenanthrene levels (0.95, 6.29, 38.5, 58.7, 122, and 303 μg g(-1) dry soil) and aged for 69 days. Multiple species (viz. Brassica rapa, Eisenia feotida, Vibrio fischeri), representing different trophic levels, were used as bioindicator organisms. Among acute toxicity assays tested, the V. fischeri luminescence inhibition assay was the most sensitive indicator of phenanthrene biotoxicity. More than 15 % light inhibition was found at the lowest phenanthrene level (0.95 μg g(-1)). Furthermore, comet assay using E. fetida was applied to assess genotoxicity of phenanthrene. The strong correlation (r (2) ≥ 0.94) between phenanthrene concentration and DNA damage indicated that comet assay is appropriate for testing the genotoxic effects of phenanthrene-contaminated soil. In the light of these results, we conclude that the Microtox test and comet assay are robust and sensitive bioassays to be employed for the risk evaluation of polycyclic aromatic hydrocarbon-contaminated soil.

  13. Spatial Distribution of Bacterial Communities and Phenanthrene Degradation in the Rhizosphere of Lolium perenne L.

    PubMed Central

    Corgié, S. C.; Beguiristain, T.; Leyval, C.

    2004-01-01

    Rhizodegradation of organic pollutants, such as polycyclic aromatic hydrocarbons, is based on the effect of root-produced compounds, known as exudates. These exudates constitute an important and constant carbon source that selects microbial populations in the plant rhizosphere, modifying global as well as specific microbial activities. We conducted an experiment in two-compartment devices to show the selection of bacterial communities by root exudates and phenanthrene as a function of distance to roots. Using direct DNA extraction, PCR amplification, and thermal gradient gel electrophoresis screening, bacterial population profiles were analyzed in parallel to bacterial counts and quantification of phenanthrene biodegradation in three layers (0 to 3, 3 to 6, and 6 to 9 mm from root mat) of unplanted-polluted (phenanthrene), planted-polluted, and planted-unpolluted treatments. Bacterial community differed as a function of the distance to roots, in both the presence and the absence of phenanthrene. In the planted and polluted treatment, biodegradation rates showed a strong gradient with higher values near the roots. In the nonplanted treatment, bacterial communities were comparable in the three layers and phenanthrene biodegradation was high. Surprisingly, no biodegradation was detected in the section of planted polluted treatment farthest from the roots, where the bacterial community structure was similar to those of the nonplanted treatment. We conclude that root exudates and phenanthrene induce modifications of bacterial communities in polluted environments and spatially modify the activity of degrading bacteria. PMID:15184156

  14. Enhancing phenanthrene biomineralization in a polluted soil using gaseous toluene as a cosubstrate.

    PubMed

    Ortiz, Irmene; Auria, Richard; Sigoillot, Jean-Claude; Revah, Sergio

    2003-02-15

    Laboratory experiments were conducted to study the potential of adding gaseous toluene, as a readily degradable carbon source, to enhance phenanthrene mineralization in polluted soil (1,000 mg/kg(dry soil)) aged for 400 days. Experiments were conducted in 0.5-L column reactors packed with a mixture of (80:20 w(wet)/w(wet)) spiked soil and vermiculite and fed with 1 g m(-3)reactor h(-1) toluene load in air. Removal efficiencies of 100% for toluene and greater than 95% for phenanthrene were obtained in 190 h. Evolved CO2 showed that phenanthrene mineralization increased from 39% to 86% in columns treated with gaseous toluene. Phthalic acid was identified as the principal soluble intermediate, which accumulated when no toluene was added. Increased phenanthrene uptake and mineralization with toluene can be attributed to increased biomass and the induction of enzymes involved in the intermediate mineralization. In microcosm experiments, phthalic acid mineralization increased from 19% to 81% within 50 h in the presence of toluene. Experiments with 14C-labeled phenanthrene confirmed the enhancement of phenanthrene mineralization from 45% to 83% in 385 h with toluene as a second carbon source. The results indicate thatthe addition of an appropriate gaseous cosubstrate could be an adequate strategy to enhance mineralization of PAHs in soil.

  15. Pyrene and phenanthrene sorption to model and natural geosorbents in single- and binary-solute systems.

    PubMed

    Zhang, Jing; Séquaris, Jean-Marie; Narres, Hans-Dieter; Vereecken, Harry; Klumpp, Erwin

    2010-11-01

    Sorption of pyrene and phenanthrene to model (illite and charcoal) and natural (Yangtze sediment) geosorbents were investigated by batch techniques using fluorescence spectroscopy. A higher adsorption of phenanthrene was observed with all sorbents, which is related to the better accessibility of smaller molecules to micropores in the molecular sieve sorbents. In addition, pyrene sorption in binary-solute systems with a constant initial concentration of phenanthrene (0.1 μmol L(-1) or 2 μmol L(-1)) was studied. A 0.1 μmol L(-1) concentration of phenanthrene causes no competitive effect on the pyrene sorption. A 2 μmol L(-1) concentration of phenanthrene significantly suppresses the sorption of pyrene, especially in the low concentration range; nonlinearity of the pyrene sorption isotherms thus decreases. The competitive effect of 2 μmol L(-1) phenanthrene on the pyrene sorption is overestimated by the ideal adsorbed solution theory (IAST) using the fitted single sorption results of both solutes. An adjustment of the IAST application by taking into account the molecular sieve effect is proposed, which notably improves the IAST prediction for the competitive effect.

  16. Humic substances enhance chlorothalonil phototransformation via photoreduction and energy transfer.

    PubMed

    Porras, Jazmín; Fernández, Jhon J; Torres-Palma, Ricardo A; Richard, Claire

    2014-02-18

    The photodegradation of chlorothalonil, a polychlorinated aromatic fungicide widely used in agriculture, was investigated under ultraviolet-visible irradiation in the presence and absence of different humic substances that significantly enhance the chlorothalonil phototransformation. On the basis of a kinetic model, an analytical study, the effect of scavengers, the chlorothalonil phosphorescence measurement, and varying irradiation conditions, it was possible to demonstrate that this accelerating effect is due to their capacity to reduce the chlorothalonil triplet state via H-donor reaction and to energy transfer from the triplet humic to ground state chlorothalonil. Energy transfer occurs at wavelengths below 450 nm and accounts for up to 30% of the reaction in deoxygenated medium upon irradiation with polychromatic light (300-450 nm). This process is more important with Elliott humic and fulvic acids and with humic acids extracted from natural carbonaceous material than with Nordic NOM and Pahokee peat humic acids. The obtained results are of high relevance to understanding the processes involved in chlorothalonil phototransformation and the photoreactivity of humic substances. Chlorothalonil is one of the rare molecules shown to react by energy transfer from excited humic substances.

  17. Generation of hydroxyl radicals from metal-loaded humic acids

    SciTech Connect

    Paciolla, M.D.; Jansen, S.A.; Davies, G.

    1999-06-01

    Humic acids (HAs) are naturally occurring biopolymers that are ubiquitous in the environment. They are most commonly found in the soil, drinking water, and a variety of plants. Pharmacological and therapeutic studies involving humic acids have been reported to some extent. However, when certain transition metals are bound to humic acids, e.g., iron and copper, they can be harmful to biological organisms. For this study, humic acids were extracted from German, Irish, and New Hampshire soils that were selectively chosen because of their reich abundance in humic material. Each sample was treated at room temperature with 0.1 M ferric and cupric solutions for 48 h. The amount of iron and copper adsorbed by humic acid was accurately quantitated using atomic absorption spectroscopy. The authors further demonstrate that these metal-loaded humic acids can produce deleterious oxidizing species such as the hydroxyl radical (HO*) through the metal-driven Fenton reaction. Electron paramagnetic resonance (EPR) employing spin trapping techniques with 5,5-dimethylpyrroline N-oxide (DMPO) is used to confirm the generation of hydroxyl radicals. The DMPO-OH adduct with hyperfine splitting constants A{sub N} = A{sub H} = 14.9 G is observed upon the addition of exogenous hydrogen peroxide. The concentration of hydroxyl radical was determined using 4-hydroxytempo (TEMPO-OH) as a spin standard. The presence of another oxidizing species, Fe{double_bond}O{sup 2+}, is also proposed in the absence of hydrogen peroxide.

  18. Mutagenic activity in humic water and alum flocculated humic water treated with alternative disinfectants.

    PubMed

    Backlund, P; Kronberg, L; Pensar, G; Tikkanen, L

    1985-12-01

    Mutagenic activity in Salmonella typhimurium strains TA 100, TA 98 and TA 97 has been determined for humic water and alum flocculated humic water, treated with the alternative disinfectants chlorine, ozone, chlorine dioxide, ozone/chlorine and chlorine/chlorine dioxide. The most pronounced activity was found for chlorine treated water tested on strain TA 100 without metabolic activation (S9 mix). Ozone treatment prior to chlorination did not alter the activity, while treatment with chlorine in combination with chlorine dioxide reduced the activity to a level somewhat over the background. No mutagenic response was detected in waters treated with ozone or chlorine dioxide alone. In presence of S9 mix all water extracts studied were non-mutagenic.

  19. Enumeration of phenanthrene-degrading bacteria by an overlayer technique and its use in evaluation of petroleum-contaminated sites

    SciTech Connect

    Bogardt, A.H.; Hemmingsen, B.B. )

    1992-08-01

    Bacteria that are capable of degrading polycyclic aromatic hydrocarbons were enumerated by incorporating soil and water dilutions together with fine particles of phenanthrene, a polycyclic aromatic hydrocarbon, into an agarose overlayer and pouring the mixture over a mineral salts underlayer. The phenanthrene-degrading bacteria embedded in the overlayer were recognized by a halo of clearing in the opaque phenanthrene layer. Diesel fuel- or creosote-contaminated soil and water that were undergoing bioremediation contained 6 [times] 10[sup 6] to 100 [times] 10[sup 6] phenanthrene-degrading bacteria per g and ca. 5 [times] 10[sup 5] phenanthrene-degrading bacteria per ml, respectively, whereas samples from untreated polluted sites contained substantially lower numbers. Unpolluted soil and water contained no detectable phenanthrene degraders or only very modest numbers of these organisms.

  20. Toxicity of polycyclic aromatic hydrocarbons. I. Effect of phenanthrene, pyrene, and their ozonized products on blood chemistry in rats

    SciTech Connect

    Yoshikawa, T.; Ruhr, L.P.; Flory, W.; Giamalva, D.; Church, D.F.; Pryor, W.A.

    1985-06-30

    Male Sprague-Dawley rats were treated with a single ip injection of physiological saline (3.0 ml/kg), dimethyl sulfoxide (DMSO, 3.0 ml/kg), phenanthrene (150 mg/kg), ozonized products of phenanthrene (150 mg/kg), pyrene (150 mg/kg), or ozonized products of pyrene (150 mg/kg). Phenanthrene, pyrene, and their ozonized products were dissolved in DMSO (50 mg/ml). Serum aspartate aminotransferase (AST) activity was increased significantly 24 hr after ip administration of DMSO when compared with physiological saline. Phenanthrene produced a significant elevation of serum AST and gamma-glutamyl transpeptidase (GGTP) levels related to physiological saline and DMSO-injected rats 24 hr after injection. However, GGTP levels for groups treated with DMSO or phenanthrene were not significantly increased when compared with saline groups 72 hr after injection. Ozonized products of phenanthrene produced a significant elevation of serum AST, alanine aminotransferase (ALT), GGTP, and bilirubin levels when compared with groups treated with physiological saline, DMSO, and phenanthrene 24 or 72 hr after injections. The ozonized products of phenanthrene also produced significant elevation of serum creatinine levels compared with physiological saline, DMSO, and phenanthrene groups at 24 hr after treatment and of blood urea nitrogen (BUN) levels at 24 and 72 hr.

  1. Photochemical aspects related to humic substances

    SciTech Connect

    Frimmel, F.H. )

    1994-01-01

    Dissolved humic substances (HS) show yellow color and relatively strong absorption in the UV range [a(254 nm) ca. 0.04 cm[sup [minus]1] for c(DOC) = 1 mg/L]. This is the basis for photochemical reactions in the photic zone of aquatic systems and in water treatment using IV sources. Even though understanding the mechanisms involved in the energy transfer and the resulting reactions is hampered by the poorly defined structure of HS, reliable information has been gathered on some typical aspects of their photochemistry. The luminescence of HS can be influenced and partly quenched by molecular interactions with other water constituents (e.g., heavy metals and organic micropollutants). The presence of oxygen may lead to the sensitized production of singlet oxygen (O[sub 2]), that can react specifically with substances containing diene structures or low valent sulfur. Because of the presence of these structures in HS, humic molecules will also react with the sensitized products. As a consequence, their biological, chemical, and physical properties are influenced. In addition, HS have a significant impact on the photochemical treatment of organic micropollutants in water. This has to be kept in mind when using photochemical steps for water treatment. The results from model experiments reflecting the conditions in surface water and in water treatment are given and discussed. In the presence of H[sub 2]O[sub 2], irradiation led to a transformation and partial degradation of HS. The rate of photochemical degradation of pesticides (e.g., atrazine) was decreased in the presence of HS. Fe and Mn quenched the luminescence. From this, a decrease of excited states of HS for sensitizing reactions can be deduced. The results suggest the manyfold and significant influences of HS on the photochemistry of aquatic systems. 66 refs., 9 figs., 7 tabs.

  2. High-pressure/high-temperature gas-solubility study in hydrogen-phenanthrene and methane-phenanthrene systems using static and chromatographic techniques

    SciTech Connect

    Malone, P.V.

    1987-01-01

    The design and discovery of sources for alternative energy such as coal liquefaction has become of major importance over the past two decades. One of the major problems in such design in the lack of available data, particularly, for gas solubility in polycyclic aromatics at high temperature and pressure. Static and gas-liquid partition chromatographic methods were used for the study of hydrogen-phenanthrene and methane-phenanthrene systems. The static data for these two binaries were taken along 398.2, 423.2, 448.2, and 473.2 K isotherms up to 25.23 MPa. Gas-liquid partition chromatography was used to study the infinite dilution behavior of methane, ethane, propane, n-butane, and carbon dioxide in the hydrogen-phenanthrene system as well as hydrogen, ethane, n-butane, and carbon dioxide in the methane-phenanthrene binary. The principle objective was to examine the role of the elution gas. Temperatures were along the same isotherms as the static data and up to 20.77 MPa. With the exception of carbon dioxide, Henry's constants were calculated for all systems. Expressions for the heat of solution as a function of pressure were derived for both binary and chromatographic data. Estimates of delta H/sub i/sup sol/ at high pressure were presented.

  3. Carbon Nanotube Properties Influence Adsorption of Phenanthrene and Subsequent Bioavailability and Toxicity to Pseudokirchneriella subcapitata.

    PubMed

    Glomstad, Berit; Altin, Dag; Sørensen, Lisbet; Liu, Jingfu; Jenssen, Bjørn M; Booth, Andy M

    2016-03-01

    The bioavailability of organic contaminants adsorbed to carbon nanotubes (CNTs) remains unclear, especially in complex natural freshwaters containing natural organic matter (NOM). Here, we report on the adsorption capacity (Q(0)) of five CNTs exhibiting different physicochemical properties, including a single-walled CNT (SWCNTs), multiwalled CNTs (MWCNT-15 and MWCNT-30), and functionalized MWCNTs (hydroxyl, -OH, and carboxyl, -COOH), for the model polycyclic aromatic hydrocarbon phenanthrene (3.1-800 μg/L). The influence of phenanthrene adsorption by the CNTs on bioavailability and toxicity was investigated using the freshwater algae Pseudokirchneriella subcapitata. CNTs were dispersed in algal growth media containing NOM (DOC, 8.77 mg/L; dispersed concentrations: 0.5, 1.3, 1.3, 3.3, and 6.1 mg/L for SWCNT, MWCNT-15, MWCNT-30, MWCNT-OH, and MWCNT-COOH, respectively). Adsorption isotherms of phenanthrene to the dispersed CNTs were fitted with the Dubinin-Ashtakhov model. Q(0) differed among the CNTs, increasing with increasing surface area and decreasing with surface functionalization. SWCNT and MWCNT-COOH exhibited the highest and lowest log Q(0) (8.891 and 7.636 μg/kg, respectively). The presence of SWCNTs reduced phenanthrene toxicity to algae (EC50; 528.4) compared to phenanthrene-only (EC50; 438.3), and the presence of MWCNTs had no significant effect on phenanthrene toxicity. However, phenanthrene adsorbed to NOM-dispersed CNTs proved to be bioavailable and contribute to exert toxicity to P. subcapitata.

  4. Discrete electronic-vibrational fluorescence spectra in the low-pressure phenanthrene and naphthacene vapors

    SciTech Connect

    Mirumyants, S.O.; Kozlov, V.K.; Vandyukov, E.A.

    1986-10-01

    In recent years considerable attention has been paid to developing methods for analysis and control of air pollutants. In this work the results of the study on quasiline fluorescence spectra for phenathrene and naphthacene in the gas phase are presented. Despite the fact that phenanthrene is a stereoisomer of anthracene, the shapes and intensities of their absorption and fluorescence spectra are markedly different. The oscillator strength of the first electronic transition in anthracene vapors is 50 times larger than that for the phenanthrene vapor (0.1 and 0.002, respectively). Therefore, the studies of the quasiline fluorescence spectrum of the phenanthrene vapor required a long exposition period (from 7 to 31 h) during the photographic detection. It is known that phenanthrene exhibits a characteristic quasiline spectrum in the 34584000-A range in frozen solutions. The authors have also investigated the possibility of obtaining structured quasiline vapor spectra for a more complex aromatic compound such as naphthacene which comprises four benzyl rings. In conclusion, the quasiline fluorescence spectra for phenanthrene and naphthacene in the gas phase have been obtained for the first time. In certain experimental conditions, phenanthrene and naphthacene emit wellresolved quasiline spectra which are dependent on the excitation frequency, temperature, and vapor pressure. For both compounds there is a frequency range for quasiline fluorescence excitation for which a shift of the quasiline spectrum occurs if the excitation frequency is changed within that range. Also more accurate values for the frequencies of the O-O electronic transition in phenanthrene and naphthacene have been obtained. Diagrams are included.

  5. Proteomic analysis of plasma membrane proteins in wheat roots exposed to phenanthrene.

    PubMed

    Shen, Yu; Du, Jiangxue; Yue, Le; Zhan, Xinhua

    2016-06-01

    Polycyclic aromatic hydrocarbons (PAHs) are potentially carcinogenic and toxic to humans through ingestion of contaminated food crops. PAHs can enter crop roots through proton/PAH symporters; however, to date, the symporter remains unclear. Here we reveal, for the first time, the plasma membrane proteome of Triticum aestivum seedling roots in response to phenanthrene (a model PAH) exposure. Two-dimensional gel electrophoresis (2-DE) coupled with MALDI-TOF/TOF-MS and protein database search engines were employed to analyze and identify phenanthrene-responsive proteins. Over 192 protein spots are reproducibly detected in each gel, while 8 spots are differentially expressed under phenanthrene treatment. Phenanthrene induces five up-regulated proteins distinguished as 5-methyltetrahydropteroyltriglutamate-homocysteine methyltransferase 2, enolase, heat shock protein 80-2, probable mediator of RNA polymerase II transcription subunit 37e (heat shock 70-kDa protein 1), and lactoylglutathione lyase. Three proteins identified as adenosine kinase 2, 4-hydroxy-7-methoxy-3-oxo-3,4-dihydro-2H-1,4-benzoxazin-2-yl glucoside beta-D-glucosidase 1c, and glyceraldehyde-3-phosphate dehydrogenase 3 are down-regulated under exposure to phenanthrene. The up-regulated proteins are related to plant defense response, antioxidant system, and glycolysis. The down-regulated proteins involve the metabolism of high-energy compounds and plant growth. Magnesium, which is able to bind to enolase, can enhance the transport of phenanthrene into wheat roots. Therefore, it is concluded that phenanthrene can induce differential expression of proteins in relation to carbohydrate metabolism, self-defense, and plant growth on wheat root plasma membrane. This study not only provides novel insights into PAH uptake by plant roots and PAH stress responses, but is also a good starting point for further determination and analyses of their functions using genetic and other approaches.

  6. Carbon 13 chemical shift tensors in aromatic compounds. 3. Phenanthrene and triphenylene

    SciTech Connect

    Soderquist, A.; Hughes, C.D.; Horton, W.J.; Facelli, J.C.; Grant, D.M.

    1992-04-08

    Measurements of the principal values of the {sup 13}C chemical shift tensor are presented for the three carbons in triphenylene and for three different {alpha} carbons in phenanthrene. The measurements in triphenylene were made in natural abundance samples at room temperature, while the phenanthrene tensors were obtained from selectively labeled compounds (99% {sup 13}C) at low temperatures ({approx} 25 K). The principal values of the shift tensors were oriented in the molecular frame using ab initio LORG calculations. The steric compression at C{sub 4} in phenanthrene and in corresponding positions in triphenylene is manifested in sizable upfield shift in the {sigma} 33 component relative to the corresponding {sigma} 33 values at C{sub 1} and C{sub 9} in phenanthrene. The upfield shift in {sigma} 33 is mainly responsible for the well-known upfield shift of the isotropic chemical shifts of such sterically perturbed carbons. In phenanthrene c{sub 9} exhibits a unique {sigma} 22 value reflecting the greater localization of {pi}-electrons in the c{sub 9}-C{sub 10} bond. This localization of the {pi}-electrons at the C{sub 9}-C{sub 10} bond in the central ring of phenanthrene also corresponds with the most likely ordering of electrons described by the various Kekule structures in phenanthrene. The analysis of the {sup 13}C chemical shieldings of the bridgehead carbons in the triphenylene provides significant experimental information on bonding between rings in polycyclic aromatic compounds. 39 refs., 8 fig., 3 tab.

  7. Adsorption of humic acids and trace metals in natural waters

    NASA Technical Reports Server (NTRS)

    Leung, W. H.

    1982-01-01

    Studies concerning the interactions between suspended hydrous iron oxide and dissolved humic acids and trace metals are reported. As a major component of dissolved organic matters and its readiness for adsorption at the solid/water interface, humic acids may play a very important role in the organometallic geochemistry of suspended sediments and in determining the fate and distribution of trace metals, pesticides and anions in natural water systems. Most of the solid phases in natural waters contain oxides and hydroxides. The most simple promising theory to describe the interactions of hydrous iron oxide interface is the surface complex formation model. In this model, the adsorptions of humic acids on hydrous iron oxide may be interpreted as complex formation of the organic bases (humic acid oxyanions) with surface Fe ions. Measurements on adsorptions were made in both fresh water and seawater. Attempts have been made to fit our data to Langmuir adsorption isotherm. Adsorption equilibrium constants were determined.

  8. Humic substances interfere with detection of pathogenic prion protein

    USGS Publications Warehouse

    Smith, Christen B.; Booth, Clarissa J.; Wadzinski, Tyler J.; Legname, Giuseppe; Chappell, Rick; Johnson, Christopher J.; Pedersen, Joel A.

    2014-01-01

    Studies examining the persistence of prions (the etiological agent of transmissible spongiform encephalopathies) in soil require accurate quantification of pathogenic prion protein (PrPTSE) extracted from or in the presence of soil particles. Here, we demonstrate that natural organic matter (NOM) in soil impacts PrPTSE detection by immunoblotting. Methods commonly used to extract PrPTSE from soils release substantial amounts of NOM, and NOM inhibited PrPTSE immunoblot signal. The degree of immunoblot interference increased with increasing NOM concentration and decreasing NOM polarity. Humic substances affected immunoblot detection of prion protein from both deer and hamsters. We also establish that after interaction with humic acid, PrPTSE remains infectious to hamsters inoculated intracerebrally, and humic acid appeared to slow disease progression. These results provide evidence for interactions between PrPTSE and humic substances that influence both accurate measurement of PrPTSE in soil and disease transmission.

  9. Long term sorption kinetics of phenanthrene in aquifer materials

    SciTech Connect

    Ruegner, H.; Kleineidam, S.; Grathwohl, P.

    1999-05-15

    Most aquifer materials are heterogeneous in terms of grain size distribution and petrography. To understand sorption kinetics, homogeneous subfractions, either separated from heterogeneous sands and gravels or fragments of fresh rocks, have to be studied. In this paper the authors present data on long-term sorption kinetics of phenanthrene for homogeneous samples consisting of one type of lithocomponents or fresh rock fragments in different grain sizes. Diffusion rate constants were determined in batch experiments using a/ numerical model for retarded intraparticle pore diffusion and correlated to grain size and intraparticle porosity of the lithocomponents. Sorption isotherms were nonlinear for all samples investigated. The numerical model described the sorption kinetics very well for coarse sand and gravels. Tortuosity factors, which were obtained as final fitting factors, agreed with Archie`s law predictions based on the intraparticle porosity. The dependency of sorptive uptake on grain size revealed that for smaller grains intrasorbent diffusion may become significant. This is attributed to relatively large particulate organic matter (POM) within the sedimentary rock fragments. Specifically, charcoal and coal particles, which were found in some of the sandstones, controlled the sorptive uptake rates.

  10. Sublethal effects of phenanthrene, nicotine, and pinane on Daphnia pulex

    USGS Publications Warehouse

    Savino, Jacqueline F.; Tanabe, Lila L.

    1989-01-01

    Chronic studies of Daphnia Pulex exposed to different concentrations of phenanthrene, nicotine, and pinane produced consistent sublethal effects among replicates and concentrations. The LOEC's for growth and fecundity with each chemical tested were 3 to 30% of the 48-hr EC50's. Growth decreased as concentration increased for each chemical tested, and fecundity approached zero at 2 to 5 times the LOEC for each chemical. In this study chemicals representing PAHs, heterocyclic nitrogen compounds, and cyclic alkanes, produced detectable sublethal effects in daphnids at less than 0.1 ppm in water. These chronic studies, in conjuction with the more extensive acute toxicity testing (Passino and Smith 1987; Perry and Smith 1988; Smith et al. 1988), provided a relatively quick but thorough toxicological assessment of a large array of chemicals and demonstrated the relative importance of different classes of compounds in changing growth and survival trends in given populations of native organisms. Classic toxicity tests continue to provide a reliable backdrop of results with which the effects of new chemicals or mixtures can be compared.

  11. Polyurethane foam (PUF) passive samplers for monitoring phenanthrene in stormwater.

    PubMed

    Dou, Yueqin; Zhang, Tian C; Zeng, Jing; Stansbury, John; Moussavi, Massoum; Richter-Egger, Dana L; Klein, Mitchell R

    2016-04-01

    Pollution from highway stormwater runoff has been an increasing area of concern. Many structural Best Management Practices (BMPs) have been implemented for stormwater treatment and management. One challenge for these BMPs is to sample stormwater and monitor BMP performance. The main objective of this study was to evaluate the feasibility of using polyurethane foam (PUF) passive samplers (PSs) for sampling phenanthrene (PHE) in highway stormwater runoff and BMPs. Tests were conducted using batch reactors, glass-tube columns, and laboratory-scale BMPs (bioretention cells). Results indicate that sorption for PHE by PUF is mainly linearly relative to time, and the high sorption capacity allows the PUF passive sampler to monitor stormwater events for months or years. The PUF passive samplers could be embedded in BMPs for monitoring influent and effluent PHE concentrations. Models developed to link the results of batch and column tests proved to be useful for determining removal or sorption parameters and performance of the PUF-PSs. The predicted removal efficiencies of BMPs were close to the real values obtained from the control columns with errors ranging between -8.46 and 1.52%. This research showed that it is possible to use PUF passive samplers for sampling stormwater and monitoring the performance of stormwater BMPs, which warrants the field-scale feasibility studies in the future.

  12. Plasma polymerized allylamine coated quartz particles for humic acid removal.

    PubMed

    Jarvis, Karyn L; Majewski, Peter

    2012-08-15

    Allylamine plasma polymerization has been used to modify the surface of quartz particles for humic acid removal via an inductively coupled rotating barrel plasma reactor. Plasma polymerized allylamine (ppAA) films were deposited at a power of 25 W, allylamine flow rate of 4.4 sccm and polymerization times of 5-60 min. The influence of polymerization time on surface chemistry was investigated via X-ray photoelectron spectroscopy (XPS), time of flight secondary ion mass spectrometry (ToF-SIMS) and electrokinetic analysis. Acid orange 7 adsorption/desorption quantified the number of surface amine groups. Humic acid removal via ppAA quartz particles was examined by varying pH, removal time, humic acid concentration, and particle mass. Increasing the polymerization time increased the concentration of amine groups on the ppAA quartz surface, thus also increasing the isoelectric point. ToF-SIMS demonstrated uniform distribution of amine groups across the particle surface. Greatest humic acid removal was observed at pH 5 due to electrostatic attraction. At higher pH values, for longer polymerization times, humic acid removal was also observed due to hydrogen bonding. Increasing the initial humic acid concentration increased the mass of humic acid removed, with longer polymerization times exhibiting the greatest increases. Plasma polymerization using a rotating plasma reactor has shown to be a successful method for modifying quartz particles for the removal of humic acid. Further development of the plasma polymerization process and investigation of additional contaminants will aid in the development of a low cost water treatment system.

  13. Aliphatic structure of humic acids; a clue to their origin

    USGS Publications Warehouse

    Hatcher, P.G.; Maciel, G.E.; Dennis, L.W.

    1981-01-01

    Nuclear magnetic resonance spectra (both 1H and 13C) of humic acids from diverse depositional environments indicate the presence of aromatic chemical structures, most likely derived from lignin of vascular plants, and complex, paraffinic structures, most likely derived from algal or microbial sources. The latter components account for a major fraction of humic acid structures in both terrestrial and aquatic environments, suggesting that algae or microbes play a large role in humification of organic remains from both systems. ?? 1981.

  14. Capillary zone electrophoresis of humic acids from the American continent.

    PubMed

    Pacheco, Maria de Lourdes; Havel, Josef

    2002-01-01

    A multicomponent background electrolyte (BGE) was developed and its composition optimized using artificial neural networks (ANN). The optimal BGE composition was found to be 90 mM boric acid, 115 mM Tris, and 0.75 mM EDTA (pH 8.4). A separation voltage of 20 kV, 20 degrees C and detection at 210 nm were used. The method was applied to characterize several humic acids originating from various countries of the American continent: soil (Argentina), peat (Brazil), leonardite (Guatemala and Mexico) and coal (United States). Comparison with humic acids of International Humic Substances Society (IHSS) standard samples was also done. Well reproducible electropherograms showing a relatively high number of peaks were obtained. Characterization of the samples by elemental analysis and UV spectrophotometry was also done. In spite of the very different origins, the similarities between humic acids are high and by matrix assisted desorption/ionization-time of flight (MALDI-TOF)-mass spectrometry it was shown that most of the m/z patterns are the same in all humic acids. This means that humic acids of different origin have the same structural units or that they contain the same components.

  15. Sorption/desorption reversibility of phenanthrene in soils and carbonaceous materials

    SciTech Connect

    Guohui Wang; Sybille Kleineidam; Peter Grathwohl

    2007-02-15

    Sorption/desorption of phenanthrene in two soil samples and carbonaceous materials was found to yield co-incident equilibrium isotherms and no significant hysteresis was observed. Additionally, release of native phenanthrene was investigated. Equilibrium sorption and desorption isotherms were determined using pulverized samples of Pahokee peat, lignite, and high-volatile bituminous coal, a mineral soil, and an anthropogenic soil. Instead of the conventional decant-and-refill batch method, sorption/desorption was driven by temperature changes using consistent samples. Sorption started at 77{sup o}C and was increased by reducing the temperature stepwise to 46, 20, and finally 4{sup o}C. For desorption the temperature was increased stepwise again until 77{sup o}C was reached. Besides the co-incident sorption and desorption isotherms at each temperature step, the solubility-normalized sorption/desorption isotherms of all different temperatures collapse to unique overall isotherms. Leaching of native phenanthrene occurred at much lower concentrations but was well predicted by extrapolation of the spiked sorption isotherms indicating that the release of native phenanthrene involves the same sorption/desorption mechanisms as those for newly added phenanthrene. 35 refs., 4 figs., 5 tabs.

  16. Adsorption of phenanthrene on multilayer graphene as affected by surfactant and exfoliation.

    PubMed

    Zhao, Jian; Wang, Zhenyu; Zhao, Qing; Xing, Baoshan

    2014-01-01

    Surfactant mediated exfoliation of multilayer graphene and its effects on phenanthrene adsorption were investigated using a passive dosing technique. In the absence of surfactant (sodium cholate, NaC), multilayer graphene had higher adsorption capacity for phenanthrene than carbon nanotube and graphite due to the higher surface area and micropore volume. The observed desorption hysteresis is likely caused by the formation of closed interstitial spaces through folding and rearrangement of graphene sheets. In the presence of NaC (both 100 and 8000 mg/L), phenanthrene adsorption on graphene was decreased due to the direct competition of NaC molecules on the graphene surface. With the aid of sonication, multilayer graphene sheets were exfoliated by NaC, leading to better dispersion. The degree of dispersion depended on the graphene-NaC ratio in aqueous solution rather than critical micelle concentration of NaC, and the good dispersion occurred after reaching adsorption saturation of NaC molecules on graphene sheets. In addition, exfoliation weakened the competition between phenanthrene and NaC and enhanced the adsorption capacity of graphene for phenanthrene due to exposed new sites. The findings on exfoliation of graphene sheets and related adsorption properties highlight not only the potential applications of multilayer graphene as efficient adsorbent but also its possible environmental risk.

  17. Stereoselective metabolism of anthracene and phenanthrene by the fungus Cunninghamella elegans

    SciTech Connect

    Cerniglia, C.E.; Yang, S.K.

    1984-01-01

    The fungus Cunninghamella elegans oxidized anthracene and phenanthrene to form predominately transdihydrodiols. The metabolites were isolated by reversed-phase high-pressure liquid chromatography for structural and conformational analyses. Comparison of the circular dichroism spectrum of the fungal trans-1,2-dihydroxy-1,2-dihydroanthracene to that formed by rat liver microsomes indicated that the major enantiomer of the trans-1,2-dihydroxy-1,2-dihydroanthracene formed by C. elegans had an S,S absolute stereochemistry, which is opposite to the predominately 1R,2R dihydrodiol formed by rat liver microsomes. C. elegans oxidized phenanthrene primarily in the 1,2-positions to form trans-1,2-dihydroxy-1,2-dihydrophenanthrene. In addition, a minor amount of trans-3,4-dihydroxy-3,4-dihydrophenanthrene was detected. Metabolism at the K-region (9,10-positions) of phenanthrene was not detected. Comparison of the circular dichroism spectra of the phenanthrene trans-1,2- and trans-3,4-dihydrodiols formed by C. elegans to those formed by mammalian enzymes indicated that each of the dihydrodiols formed by C. elegans had an S,S absolute configuration. The results indicate that there are differences in both the regio- and stereoselective metabolism of anthracene and phenanthrene between the fungus C. elegans and rat liver microsomes. 26 references.

  18. Impact of activated carbon on the catabolism of (14)C-phenanthrene in soil.

    PubMed

    Oyelami, Ayodeji O; Ogbonnaya, Uchenna; Muotoh, Chitom; Semple, Kirk T

    2015-06-01

    Activated carbon amendment to contaminated soil has been proposed as an alternative remediation strategy to the management of persistent organic pollutant in soils and sediments. The impact of varying concentrations (0%, 0.01%, 0.1% and 1.0%) of different types of AC on the development of phenanthrene catabolism in soil was investigated. Mineralisation of (14)C-phenanthrene was measured using respirometric assays. The increase in concentration of CB4, AQ5000 or CP1 in soil led to an increase in the length of the lag phases. Statistical analyses showed that the addition of increasing concentrations of AC to the soil significantly reduced (P < 0.05) the extent of (14)C-phenanthrene mineralisation. For example, for CB4-, AQ5000- and CP1-amended soils, the overall extent of (14)C-phenanthrene mineralisation reduced from 43.1% to 3.28%, 36.9% to 0.81% and 39.6% to 0.96%, respectively, after 120 days incubation. This study shows that the properties of AC, such as surface area, pore volume and particle size, are important factors in controlling the kinetics of (14)C-phenanthrene mineralisation in soil.

  19. Ethanol and phenanthrene increase the biomass of fungal assemblages and decrease plant litter decomposition in streams.

    PubMed

    Barros, Diana; Oliveira, Patrícia; Pascoal, Cláudia; Cássio, Fernanda

    2016-09-15

    Fungi, particularly aquatic hyphomycetes, have been recognized as playing a dominant role in microbial decomposition of plant litter in streams. In this study, we used a microcosm experiment with different levels of fungal diversity (species number and identity) using monocultures and combinations with up to five aquatic hyphomycete species (Articulospora tetracladia, Tricladium splendens, Heliscus submersus, Tetrachaetum elegans and Flagellospora curta) to assess the effects of ethanol and phenanthrene on three functional measures: plant litter decomposition, fungal biomass accrual and reproduction. Alder leaves were conditioned by fungi for 7days and then were exposed to phenanthrene (1mgL(-1)) dissolved in ethanol (0.1% final concentration) or ethanol (at the concentration used to solubilise phenanthrene) for further 24days. Exposure to ethanol alone or in combination with phenanthrene decreased leaf decomposition and fungal reproduction, but increased fungal biomass produced. All aspects of fungal activity varied with species number. Fungal activity in polycultures was generally higher than that expected from the sum of the weighted performances of participating species in monoculture, suggesting complementarity between species. However, the activity of fungi in polycultures did not exceed the activity of the most productive species either in the absence or presence of ethanol alone or with phenanthrene.

  20. Biodegradation of phenanthrene in sand columns in the presence of nonionic surfactants

    SciTech Connect

    Norris, D.; Ahmed, T.

    1994-12-31

    The effects of three nonionic surfactants on phenanthrene (C{sub 14}H{sub 10}) removal and mineralization by aerobic bacteria were studied using a bench-scale apparatus. Columns were packed with fine sand coated with a mixture of (9-{sup 14}C) labeled and unlabeled phenanthrene (0.33 mg/g) and then inoculated by pumping acclimated bacteria. Surfactants at a concentration of 50 mg/L in an oxygenated buffer solution were then pumped through the media for 14 days at average pore velocities of 1 m/d to 3 m/d. Mineralization of phenanthrene was estimated by {sup 14}CO{sub 2} activity in the column effluent and total removal was measured by the change in {sup 14}C activity of the sand. Depending on the surfactant, mineralization was either inhibited or enhanced. A two-fold increase in flow rate increased phenanthrene mineralization and total removal greater than the effect of surfactant addition alone. Total removal ranged from 86.4% to 40.3% of the initial phenanthrene present.

  1. Spatial and temporal variation of phenanthrene-degrading bacteria in intertidal sediments

    SciTech Connect

    Berardesco, G.; Dyhrman, S.; Gallagher, E.; Shiaris, M.P.

    1998-07-01

    Phenanthrene-degrading bacteria were isolated from a 1-m{sup 2} intertidal sediment site in Boston Harbor. Samples were taken six times over 2 years. A total of 432 bacteria were isolated and characterized by biochemical testing. When clustered on the basis of phenotypic characteristics, the isolates could be separated into 68 groups at a similarity level of approximately 70%. Several groups corresponded to well-characterized species belonging the genera Vibrio and Pseudomonas. Only 51 of the 437 isolates hybridized to a DNA probe that encodes the upper pathway of naphthalene and phenanthrene degradation in Pseudomonas putida NCIB 9816. A cluster analysis indicated that the species composition of the phenanthrene-degrading community changed significantly from sampling date to sampling date. At one sampling time, 12 6-mm-diameter core subsamples were taken within the 1-m{sup 2} site to determine the spatial variability of the degrading communities. An analysis of molecular variance, performed with the phenotypic characteristics, indicated that only 6% of the variation occurred among the 12 subsamples, suggesting that the subsamples were almost identical in composition. The authors concluded that the communities of phenanthrene-degrading bacteria in the sediments are very diverse, that the community structure undergoes significant change with time but does not vary significantly on a spatial scale of centimeters, and that the predominant genes that encode phenanthrene degradation in the communities are not well-characterized.

  2. The development of phenanthrene catabolism in soil amended with transformer oil.

    PubMed

    Lee, Philip H; Doick, Kieron J; Semple, Kirk T

    2003-11-21

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants frequently associated with light non-aqueous-phase liquids (LNAPLs) in soil. Microbial degradation comprises a major loss process for PAHs in the environment. Various laboratory studies, using known degraders, have shown reduced or enhanced mineralisation of PAHs when dissolved in different LNAPLs. Effects due to the presence of LNAPLs on indigenous micro-organisms, however, are not fully understood. A pristine pasture soil was spiked with [14C]phenanthrene and transformer oil to 0, 0.01 and 0.1%, and incubated for 180 days. The catabolic potential of the soil towards phenanthrene was assessed periodically during ageing. The extent of the lag phase (prior to >5% mineralisation), maximum rates and overall extents of mineralisation observed during the course of a 14-day bioassay appeared to be dependent upon phenanthrene concentration, the presence of transformer oil, and soil-contaminant contact time. Putatively, transformer oil enhanced acclimation and facilitated the development of measurable catabolic activity towards phenanthrene in a previously uncontaminated pasture soil. Exact mechanisms for the observed enhancement, longer-term fate/degradation of the oil and residual phenanthrene, and effects of the presence of the oil on the indigenous microbes over extended time frames warrant further investigation.

  3. Viability of phenanthrene biodegradation by an isolated bacterial consortium: optimization and scale-up.

    PubMed

    Moscoso, F; Ferreira, L; Deive, F J; Morán, P; Sanromán, M A

    2013-02-01

    In the present work, biodegradation of phenanthrene by a bacterial consortium (LB2), isolated from lab-polluted soils has been investigated. The 16S rRNA gene-based molecular analysis revealed that the bacterial consortium LB2 consisted of two strains showing a very high homology with Staphylococcus warneri and Bacillus pumilus. The optimization of phenanthrene degradation by the consortium LB2, using a central composite face-centered design was carried out taking into account three important parameters such as temperature, pH, and phenanthrene concentration. Near complete phenanthrene degradation was reached by consortium LB2 at the optimal conditions (pH of 7.5 and 37.5 °C) in less than 48 h. Moreover, the efficiency of phenanthrene biodegradation was assessed by using logistic and Luedeking and Piret-type models. Finally, the process was implemented at bench-scale bioreactor and the main degradation routes were identified based on GC-MS data.

  4. Nitrite-induced enhancement of toxicity of phenanthrene in fish and its implications for coastal waters

    NASA Astrophysics Data System (ADS)

    Shailaja, M. S.; Rodrigues, A.

    2003-04-01

    Coastal areas are prone to varying degrees of anthropogenic chemical contamination. In many coastal environments experiencing reducing conditions in the water column, nitrite is produced as a result of denitrification. With a view to determining the effect of a natural stress such as the presence of nitrite in water on the xenobiotic metabolism in fish, the euryhaline cichlid Oreochromis mossambicus was exposed for up to 9 days to environmentally relevant concentrations of water-borne nitrite and phenanthrene, a polycyclic aromatic hydrocarbon. Analyses of different biomarkers in the treated fish indicated significant increase in the metabolism of phenanthrene as a result of exposure to nitrite. For example, the activity of the biotransformation enzyme measured as 7-ethoxyresorufin- O-deethylase activity was, in the presence of 1 μM nitrite, nearly twice that produced by phenanthrene alone. Similarly, biliary fixed fluorescence values reflecting phenanthrene and its metabolites were rendered 1.7 times higher when exposed simultaneously to nitrite. Contact with nitrite and phenanthrene together also led to severe hepatic damage with possible cell death as inferred from the large enhancement in sorbitol dehydrogenase activity in the serum and reduced liver somatic index.

  5. The impact of biochar on the bioaccessibility of (14)C-phenanthrene in aged soil.

    PubMed

    Ogbonnaya, O U; Adebisi, O O; Semple, K T

    2014-11-01

    Biochar is a carbon rich product from the incomplete combustion of biomass and it has been shown to reduce bioavailability of organic contaminants through adsorption. This study investigated the influence of 0%, 1%, 5% and 10% of two different particle sized wood biochars (≤2 mm and 3-7 mm) on the bioaccessibility of (14)C-phenanthrene (10 mg kg(-1)) in aged soil. The extent of (14)C-phenanthrene mineralisation by phenanthrene-degrading Pseudomonas sp. inoculum was monitored over a 14 day period in respirometric assays and compared to hydroxypropyl-β-cyclodextrin (HPCD) aqueous extraction. Notably, biochar amendments showed significant reduction in extents of mineralisation and HPCD extraction. Linear correlations between HPCD extractability and the total amount mineralised revealed good correlations, with 2 mm biochar showing a best fit (r(2) = 0.97, slope = 1.11, intercept = 1.72). Biochar reduced HPCD extractability and bioaccessibility of (14)C-phenanthrene to microorganisms in a similar manner. Biochar can aid risk reduction to phenanthrene exposure to biota in soil and HPCD can serve as a useful tool to assess the extent of exposure in biochar-amended soils.

  6. The influence of sediment resuspension on the degradation of phenanthrene in flow-through microcosms.

    PubMed

    LeBlanc, Lawrence A; Gulnick, Jeanne D; Brownawell, Bruce J; Taylor, Gordon T

    2006-03-01

    The effect of sediment resuspension on the mineralization of phenanthrene was examined in microcosms and sediment slurries. In computer-controlled, flow-through microcosms, 14C-phenanthrene-amended sediments were resuspended into overlying oxic water at frequencies of 12, 4, 1, 0.25 and 0 d(-1). In slurry bottle experiments 14C-phenanthrene-amended sediments were continuously resuspended under oxic (excess air headspace) and anoxic (N2 headspace) conditions and mineralization was measured at periods from 2 h to 7 days. Our main findings were: (1) mineralization rate constants from the microcosms ranged from 0.001 to 0.01 d(-1) and increased with frequency of resuspension, (2) these rates fell between those measured in oxic and anoxic slurries and were predicted within a factor of 2.5 by a model in which mineralization depended on the degree of oxygen exposure, and (3) the phenanthrene-degrading bacterial community was more active in resuspended sediments incubated in the microcosms than in sediments which were not resuspended, or which were stored under refrigeration. We conclude from these experiments that the effects of sediment resuspension on phenanthrene degradation are consistent with a primary role of average oxygen exposure, and also an alteration in the PAH-degrading activity of microbial populations.

  7. Sorption-desorption hysteresis of phenanthrene--effect of nanopores, solute concentration, and salinity.

    PubMed

    Wu, Wenling; Sun, Hongwen

    2010-11-01

    Phenanthrene sorption and desorption from sediment/soil in fresh and saline water were measured, and effects of nanopores, solute concentration, and salinity on sorption-desorption hysteresis were discussed. The extent and kinetics of sorption-desorption hysteresis depend much on the pore distribution of the sorbents, and greater but slower-developed hysteresis occurred on the sorbent with higher specific surface area and more nanopores. In saline water, phenanthrene sorption was enhanced as compared to freshwater, with logKF increasing from 2.84 and 3.08 to 2.96 and 3.33 for the two sorbents, respectively; however, the sorption-desorption hysteresis was weakened, as indicated by the lower hysteresis index in saline water as compared to those in freshwater. In successive desorption, the irreversible sorbed amount of phenanthrene increased with increasing phenanthrene concentration until a maximum (Qmaxirr) was achieved, and the subsequent sorption became reversible. In saline water, Qmaxirr is much lower (10 mg kg(-1)) as compared to freshwater (36 mg kg(-1)), and phenanthrene sorption was almost reversible, especially at high concentrations. N2 sorption illustrated that soil organic matter had changed to a more condensed conformation in saline water, as indicted by the reduced surface area (from 9.6 to 7.3 m2 g(-1)), which is unfavorable for irreversible sorption.

  8. Cytoplasmic pH-Stat during Phenanthrene Uptake by Wheat Roots: A Mechanistic Consideration.

    PubMed

    Zhan, Xinhua; Yi, Xiu; Yue, Le; Fan, Xiaorong; Xu, Guohua; Xing, Baoshan

    2015-05-19

    Dietary intake of plant-based foods is a major contribution to the total exposure of polycyclic aromatic hydrocarbons (PAHs). However, the mechanisms underlying PAH uptake by roots remain poorly understood. This is the first study, to our knowledge, to reveal cytoplasmic pH change and regulation in response to PAH uptake by wheat roots. An initial drop of cytoplasmic pH, which is concentration-dependent upon exposure to phenanthrene (a model PAH), was followed by a slow recovery, indicating the operation of a powerful cytoplasmic pH regulating system. Intracellular buffers are prevalent and act in the first few minutes of acidification. Phenanthrene activates plasmalemma and tonoplast H(+) pump. Cytolasmic acidification is also accompanied by vacuolar acidification. In addition, phenanthrene decreases the activity of phosphoenolpyruvate carboxylase and malate concentration. Moreover, phenanthrene stimulates nitrate reductase. Therefore, it is concluded that phenanthrene uptake induces cytoplasmic acidification, and cytoplasmic pH recovery is achieved via physicochemical buffering, proton transport outside cytoplasm into apoplast and vacuole, and malate decarboxylation along with nitrate reduction. Our results provide a novel insight into PAH uptake by wheat roots, which is relevant to strategies for reducing PAH accumulation in wheat for food safety and improving phytoremediation of PAH-contaminated soils or water by agronomic practices.

  9. Effects of biosurfactant-producing bacteria on biodegradation and transport of phenanthrene in subsurface soil.

    PubMed

    Chang, Jae-Soo; Cha, Daniel K; Radosevich, Mark; Jin, Yan

    2015-01-01

    This study investigated the effects of surfactant-producing microorganism, Pseudomonas aeruginosa ATCC 9027, on phenanthrene (PHE) biodegradation by two different PHE-degrading bacteria (Isolate P5-2 and Pseudomonas strain R) in soil. Phenanthrene mineralization experiments were conducted with soils inoculated with one of PHE-degraders and/or the surfactant-producer. Influence of co-inoculation with the surfactant-producing bacteria on phenanthrene transport and biodegradation was also examined in soil columns. P. strain R mineralized phenanthrene faster and to a greater extent than Isolate P5-2 in the test soil. Co-inoculation with the surfactant-producing bacteria significantly enhanced phenanthrene biodegradation by P. strain R but it did not affect the biodegradation by Isolate P5-2 in both batch and column systems. Production of biosurfactants by P. aeruginosa ATCC 9027 was negligible under the given conditions. This study demonstrated that bioaugmentation with surfactant-producing bacteria could enhance in situ bioremediation of soils contaminated with polycyclic aromatic hydrocarbons (PAHs) and the beneficial effect of the bioaugmentation depended on types of PAH-degrading microorganisms present.

  10. Using orthogonal design to determine optimal conditions for biodegradation of phenanthrene in mangrove sediment slurry.

    PubMed

    Chen, Jian Lin; Au, Kwai Chi; Wong, Yuk Shan; Tam, Nora Fung Yee

    2010-04-15

    In the present paper, the effects of four factors, each at three levels, on biodegradation of phenanthrene, a 3-ring PAH, in contaminated mangrove sediment slurry were investigated using the orthogonal experimental design. The factors and levels were (i) sediment types (clay loam, clayey and sandy); (ii) different inoculums (Sphingomonas sp., a mixture of Sphingomonas sp. and Mycobacterium sp., and without inoculum); (iii) presence of other PAHs (fluorene, pyrene, and none); and (iv) different salinities (5, 15 and 25 ppt). Variance analysis based on the percentages of Phe biodegradation showed that the presence of other PAHs had little effect on phenanthrene biodegradation. The kinetics of phenanthrene biodegradation in all experiments was best fitted by the first order rate model. The highest first order rate constant, k value was 0.1172 h(-1) with 97% Phe degradation; while the lowest k value was 0.0004 and phenanthrene was not degraded throughout the 7-d experiment. The p values of k for the four factors followed the same trend as that for the biodegradation percentage. Difference analysis revealed that optimal phenanthrene biodegradation would take place in clay loam sediment slurry at low salinity (5 to 15 ppt) with the inoculation of both Sphingomonas sp. and Mycobacterium sp.

  11. A comparison of water solubility enhancements of organic solutes by aquatic humic materials and commercial humic acids

    USGS Publications Warehouse

    Chlou, C.T.; Kile, D.E.; Brinton, T.I.; Malcolm, R.L.; Leenheer, J.A.; MacCarthy, P.

    1987-01-01

    Water solubility enhancements of 1,1-bis(p-chloro-phenyl)-2,2,2-trichloroethane (p,p???-DDT), 2,4,5,2???,5???-pentachlorobiphenyl (2,4,5,2???,5???-PCB), and 2,4,4???-tri-chlorobiphenyl (2,4,4???-PCB) by dissolved organic matter have been studied with the following samples: (1) acidic water samples from the Suwannee River, Georgia, and the Sopchoppy River, Florida; (2) a humic extract of a nearly neutral pH water from the Calcasieu River, Louisiana; (3) commercial humic acids from the Aldrich Chemical Co. and Fluka-Tridom Chemical Corp. The calculated partition coefficients on a dissolved organic carbon basis (Kdoc) for organic solutes with water samples and aquatic humic extracts from this and earlier studies indicate that the enhancement effect varies with the molecular composition of the aquatic humic materials. The Kdoc values with water and aquatic humic samples are, however, far less than the observed Kdoc values obtained with the two commercial samples, by factors of about 4-20. In view of this finding, one should be cautious in interpreting the effects of the dissolved organic matter on solubility enhancement of organic solutes on the basis of the use of commercial humic acids.

  12. Effect of humic acid source on humic acid adsorption onto titanium dioxide nanoparticles.

    PubMed

    Erhayem, Mohamed; Sohn, Mary

    2014-02-01

    In many studies, different humic acid (HA) sources are used interchangeably to evaluate the effect of organic matter on geochemical processes in the environment. This research looks more specifically at the effect of HA source on HA adsorption onto nano-TiO2 and how HA adsorption affects the fate and transport of nano-TiO2. In this study, six humic acids (HAs) were studied which were derived from soils (SLHA), or from sediments (SDHA) all originating from the state of Florida. Humic acid adsorption onto titanium dioxide nanoparticles (nano-TiO2) and the sedimentation of HA-coated and uncoated nano-TiO2 were monitored by Ultraviolet-visible (UV-vis) spectroscopy. Synchronous scan fluorescence (SSF) spectroscopy was used to complement the study of HA adsorption onto nano-TiO2. Phosphate buffer was found to reduce the amount of HA adsorbed onto nano-TiO2 relative to solutions of NaCl of the same pH and ionic strength. Adsorption constant values (Kads) for HAs varied in the order SLHA>FSDHA (freshwater sedimentary HA)>ESDHA (estuarine sedimentary HA). SSF results suggested that the more highly conjugated fractions of HA, which are more prevalent in SLHAs versus SDHAs, were preferentially adsorbed. In order to better understand the relationship between adsorption and aggregation, sedimentation studies were conducted and it was found that the percentage of nano-TiO2 sedimentation was preferentially enhanced in the order of the presence of SLHA>FSDHA>ESDHA. The extent of nano-TiO2 sedimentation was decreased with increasing HA concentration. TEM imaging of nano-TiO2 confirmed that nano-TiO2 was aggregated in the presence of HAs. The findings in this study suggest that HAs from different sources influence the fate and transport of nano-TiO2 in the environment differently.

  13. Effect of corn plant on survival and phenanthrene degradation capacity of Pseudomonas sp. UG14LR in two soils.

    PubMed

    Chouychai, Waraporn; Thongkukiatkul, Amporn; Upatham, Suchart; Pokethitiyook, Prayad; Kruatrachue, Maleeya; Lee, Hung

    2012-07-01

    A study was undertaken to assess if corn (Zea mays L.) can enhance phenanthrene degradation in two soils inoculated with Pseudomonas sp. UG14Lr. Corn increased the number of UG14Lr cells in both soils, especially in the acidic soiL Phenanthrene was degraded to a greater extent in UG14Lr-inoculated or corn-planted soils than uninoculated and unplanted soils. The spiked phenanthrene was completely removed within 70 days in all the treatments in slightly alkaline soil. However, in acidic soil, complete phenanthrene removal was found only in the corn-planted treatments. The shoot and root lengths of corn grown in UG14Lr-inoculated soils were not different from those in non-inoculated soil between the treatments. The results showed that in unplanted soil, low pH adversely affected the survival and phenanthrene degradation ability of UG14Lr. Planting of corn significantly enhanced the survival of UG14Lr cells in both the bulk and rhizospheric soil, and this in turn significantly improved phenanthrene degradation in acidic soil. Re-inoculation of UG14Lr in the acidic soil increased the number of UG14Lr cells and enhanced phenanthrene degradation in unplanted soil. However, in corn-planted acidic soils, re-inoculation of UG14Lr did not further enhance the already active phenanthrene degradation occurring in both the bulk or rhizospheric soils.

  14. MEASURING GROWTH OF A PHENANTHRENE DEGRADING BACTERIAL INOCULUM IN SOIL WITH A QUANTITATIVE COMPETITIVE POLYMERASE CHAIN REACTION METHOD. (R825433)

    EPA Science Inventory

    We measured growth of a phenanthrene-degrading bacterium, Arthrobacter, strain RP17, in Forbes soil, amended with 500 small mu, Greekg g−1 phenanthrene using a quantitati...

  15. Phenanthrene Bioavailability and Toxicity to Daphnia magna in the Presence of Carbon Nanotubes with Different Physicochemical Properties.

    PubMed

    Zindler, Florian; Glomstad, Berit; Altin, Dag; Liu, Jingfu; Jenssen, Bjørn M; Booth, Andy M

    2016-11-15

    Studies investigating the effect of carbon nanotubes (CNTs) on the bioavailability and toxicity of hydrophobic organic compounds in aquatic environments have generated contradictory results, and the influence of different CNT properties remains unknown. Here, the adsorption of the polycyclic aromatic hydrocarbon phenanthrene (70-735 μg/L) to five types of CNTs exhibiting different physical and chemical properties was studied. The CNTs were dispersed in the presence of natural organic matter (nominally 20 mg/L) in order to increase the environmental relevance of the study. Furthermore, the bioavailability and toxicity of phenanthrene to Daphnia magna in the absence and presence of dispersed CNTs was investigated. Both CNT dispersion and adsorption of phenanthrene appeared to be influenced by CNT physical properties (diameter and specific surface area). However, dispersion and phenanthrene adsorption was not influenced by CNT surface chemical properties (surface oxygen content), under the conditions tested. Based on nominal phenanthrene concentrations, a reduction in toxicity to D. magna was observed during coexposure to phenanthrene and two types of CNTs, while for the others, no influence on phenanthrene toxicity was observed. Based on freely dissolved concentrations, however, an increased toxicity was observed in the presence of all CNTs, indicating bioavailability of CNT-adsorbed phenanthrene to D. magna.

  16. [Phylogenetic analysis of the genes for naphthalene and phenanthrene degradation in Burkholderia sp. strains].

    PubMed

    Izmalkova, T Yu; Sazonova, O I; Kosheleva, I A; Boronin, A M

    2013-06-01

    The genetic systems responsible for naphthalene and phenanthrene catabolism have been analyzed in the five strains of Burkholderia sp. isolated from soil samples (West Siberia) contaminated by heavy residual fuel oil and in the strain Burkholderia sp. BS3702 from the laboratory collection isolated from soil samples of the coke gas works (Vidnoe, Moscow oblast). The results of this work demonstrate that naphthalene and phenanthrene degradation in the above strains is encoded by the sequences not homologous to the classical nah genes of pseudomonades. In the Burkholderia sp. BS3702 strain, the initial stages of phenanthrene degradation and the subsequent stages of salicylate degradation are controlled by the sequences of different evolutionary origins (phn and nag genes).

  17. Factors affecting the microbial degradation of phenanthrene in soil. (Reannouncement with new availability information)

    SciTech Connect

    Manilal, V.B.; Alexander, M.

    1991-12-31

    Because phenanthrene was mineralized more slowly in soils than in liquid media, a study was conducted to determine the environmental factors that may account for the slow biodegradation in soil. Mineralization was enhanced by additions of phosphate but not potassium, and it was reduced by additions of nitrate. Aeration or amending the soil with glucose affected the rate of mineralization, although not markedly. Phenanthrene was sorbed to soil constituents, the extent of sorption being directly related to the percentage of organic matter in the soil. Soluble phenanthrene was not detected after addition of the compound to a muck soil. The rate of mineralization was slow in the organic soil and higher in mineral soils with lower percentages of organic matter. We suggest that sorption by soil organic matter slows the biodegradation of polycyclic aromatic hydrocarbons that are otherwise readily metabolized.

  18. Metabolism of phenanthrene by the marine cyanobacterium Agmenellum quadruplicatum PR-6

    SciTech Connect

    Narro, M.L.; Baalen, C. van ); Cerniglia, C.E. ); Gibson, D.T. )

    1992-04-01

    Under photoautotrophic growth conditions, the marine cyanobacterium Agmenellum quadruplicatum PR-6 metabolized phenanthrene to form trans-9,10-dihydrophenanthrene (phenanthrene trans-9,10-dihydrodiol) and 1-methoxyphenanthrene as the major ethyl acetate-extractable metabolites. Small amounts of phenanthrols were also formed. The metabolites were purified by high-pressure liquid chromatography and identified from their UV, infrared, mass and proton magnetic resonance spectral properties. A. quadruplicatum PR-6 formed phenanthrene trans-9,10-dihydrodiol with a 22% enantiomeric excess of the ({minus})-9S,10S-enantiomer. Incorporation experiments with {sup 18}O{sub 2} showed that one atom of oxygen from O{sub 2} was incorporated into the dihydrodiol. Toxicity studies, using an algal lawn bioassay, indicated that 9-phenanthrol and 9,10-phenanthrenequinone inhibit the growth of A. quadruplicatum PR-6.

  19. Constraint on the potassium content for the superconductivity of potassium-intercalated phenanthrene

    SciTech Connect

    Huang, Qiao-Wei; Zhao, Xiao-Miao; Zhong, Guo-Hua; Zhang, Jiang; Zhang, Chao; Lin, Hai-Qing; Chen, Xiao-Jia

    2014-03-21

    Raman-scattering measurements were performed on K{sub x}phenanthrene (0 ⩽ x ⩽ 6.0) at room temperature. Three phases (x = 3.0, 3.5, and 4.0) are identified based on the obtained Raman spectra. Only the K{sub 3}phenanthrene phase is found to exhibit the superconducting transition at 5 K. The C–C stretching modes are observed to broaden and become disordered in K{sub x}phenanthrene with x = 2.0, 2.5, 6.0, indicating some molecular disorder in the metal intercalation process. This disorder is expected to influence the nonmetallic nature of these materials. The absence of metallic character in these nonsuperconducting phases is found from the calculated electronic structures based on the local density approximation.

  20. Identification of soil bacteria able to degrade phenanthrene bound to a hydrophobic sorbent in situ.

    PubMed

    Regonne, Raïssa Kom; Martin, Florence; Mbawala, Augustin; Ngassoum, Martin Benoît; Jouanneau, Yves

    2013-09-01

    Efficient bioremediation of PAH-contaminated sites is limited by the hydrophobic character and poor bioavailability of pollutants. In this study, stable isotope probing (SIP) was implemented to track bacteria that can degrade PAHs adsorbed on hydrophobic sorbents. Temperate and tropical soils were incubated with (13)C-labeled phenanthrene, supplied by spiking or coated onto membranes. Phenanthrene mineralization was faster in microcosms with PAH-coated membranes than in microcosms containing spiked soil. Upon incubation with temperate soil, phenanthrene degraders found in the biofilms that formed on coated membranes were mainly identified as Sphingomonadaceae and Actinobacteria. In the tropical soil, uncultured Rhodocyclaceae dominated degraders bound to membranes. Accordingly, ring-hydroxylating dioxygenase sequences recovered from this soil matched PAH-specific dioxygenase genes recently found in Rhodocyclaceae. Hence, our SIP approach allowed the detection of novel degraders, mostly uncultured, which differ from those detected after soil spiking, but might play a key role in the bioremediation of PAH-polluted soils.

  1. Formulation of humic-based soil conditioners

    NASA Astrophysics Data System (ADS)

    Amanova, M. A.; Mamytova, G. A.; Mamytova, B. A.; Kydralieva, K. A.; Jorobekova, Sh. J.

    2009-04-01

    The goal of the study is to prepare soil conditioners (SC) able to carry out the following functions: (i) the chemical conditioning of soil mainly comprising the adjustment of pH, (ii) the balancing of inorganic nutrients, (iii) the physical conditioning of soil mainly comprising the improvement of water permeability, air permeability and water retention properties, and (iv) improvement of the ecological system concerning of useful microorganisms activity in the soil. The SC was made of a mixture of inorganic ingredients, a chemical composition and physical and chemical properties of which promoted improvement of physical characteristic of soil and enrichment by its mineral nutritious elements. In addition to aforesaid ingredients, this soil conditioner contains agronomical-valued groups of microorganisms having the function promoting the growth of the crop. As organic component of SC humic acids (HA) was used. HA serve many major functions that result in better soil and plant health. In soil, HA can increase microbial and mycorrhizal activity while enhancing nutrient uptake by plant roots. HA work as a catalyst by stimulating root and plant growth, it may enhance enzymatic activity that in turn accelerates cell division which can lead to increased yields. HA can help to increase crop yields, seed germination, and much more. In short, humic acids helps keep healthy plants health. The first stage goal was to evaluate mineral and organic ingredients for formulation of SC. Soil conditioners assessed included ash and slag. The use of slags has been largelly used in agriculture as a source of lime and phosphoric acid. The silicic acid of slags reduces Al-acitivity thus, promoting a better assimilation of P-fertilizer by plants. Additionally, silicic acid is also known to improve soil moisture capacity, thus enhancing soil water availability to plants. Physico-chemical characteristics of ash and slag were determined, as a total - about 20 samples. Results include

  2. DBP formation of aquatic humic substances

    USGS Publications Warehouse

    Pomes, M.L.; Green, W.R.; Thurman, E.M.; Orem, W.H.; Lerch, H.E.

    1999-01-01

    Aquatic humic substances (AHSs) in water generate potentially harmful disinfection by-products (DBPs) such as haloacetic acids (HAAs) and trihalomethanes (THMs) during chlorination. AHSs from two Arkansas reservoirs were characterized to define source, identify meta-dihydroxybenzene (m-DHB) structures as probable DBP precursors, and evaluate predicted HAA and THM formation potentials. Elemental nitrogen content 0.5 ??eq/mg, ??13C values of -27???, and low yields of syringyl phenols found by cupric oxide (CuO) oxidation suggest a pine tree source for the AHSs found in the Maumelle and Winona reservoirs in Little Rock, Ark. CuO oxidation yielded fewer m-DHB structures in Maumelle AHSs than in Winona AHSs. A higher 3,5-dihydroxybenzoic acid (3,5-DHBA) content correlated with increased HAA and THM formation potential. The 3,5-DHBA concentration in Winona AHSs was similar to the range found in AHSs extracted from deciduous leaf litter, twigs, and grass leachates.

  3. Hydrophysical properties of Humic Latosols from Brazil

    NASA Astrophysics Data System (ADS)

    Ebenezer Ajayi, Ayodele; de Souza Dias, Moacir; Curi, Nilton; Moreira Pais, Paula Sant'Anna; Iori, Piero

    2014-10-01

    The hydrophysical properties of the prevalent Humic Latosols (organic matter rich and charcoal stained soils) were related to structural sustainability under loading. Intact cores collected at the Ap, AB, Bw horizons were used for hydrophysical characterization. Precompression stresses at 10 suctions were obtained to estimate the load bearing capacities. We observed the dominance of kaolinite with some occurrences of gibbsite and hydroxy-interlayered vermiculite in the clay mineralogy. The high organic matter content in the Ap horizon favours crumb structure with the structural unit presenting high porosity and water retention. The structure of the AB and Bw horizons was, however, granular with structural units having low porosity. Possible influence of earlier incidences of fire enhanced the organic matter and carbon content in the soil reducing down the profile from 42.5 g kg-1 at the Ap to 16.4 g kg-1 at the Bw horizon. The C/N ratio increased from 14 at the Ap to 17 at the Bw, and air capacity increased from 18.1% at Ap to 32.0% at Bw. Precompression stress values were: 100.6±40.7 kPa at Ap, 117.4±44.6 kPa at AB, and 116.1±58.9 kPa at Bw. Load bearing capacities at the AB and Bw horizons were homogenous.

  4. Van der Waals density functional study of the structural and electronic properties of La-doped phenanthrene

    SciTech Connect

    Yan, Xun-Wang; Huang, Zhongbing; Lin, Hai-Qing

    2013-11-28

    By the first principle calculations based on the van der Waals density functional theory, we study the crystal structures and electronic properties of La-doped phenanthrene. Two stable atomic geometries of La{sub 1}phenanthrene are obtained by relaxation of atomic positions from various initial structures. The structure-I is a metal with two energy bands crossing the Fermi level, while the structure-II displays a semiconducting state with an energy gap of 0.15 eV, which has an energy gain of 0.42 eV per unit cell compared to the structure-I. The most striking feature of La{sub 1}phenanthrene is that La 5d electrons make a significant contribution to the total density of state around the Fermi level, which is distinct from potassium doped phenanthrene and picene. Our findings provide an important foundation for the understanding of superconductivity in La-doped phenanthrene.

  5. Effects of root exudates on the leachability, distribution, and bioavailability of phenanthrene and pyrene from mangrove sediments.

    PubMed

    Jia, Hui; Lu, Haoliang; Liu, Jingchun; Li, Jian; Dai, Minyue; Yan, Chongling

    2016-03-01

    In this study, column leaching experiments were used to evaluate the leachability, distribution and bioavailability of phenanthrene and pyrene by root exudates from contaminated mangrove sediments. We observed that root exudates significantly promoted the release and enhanced the bioavailability of phenanthrene and pyrene from sediment columns. The concentration of phenanthrene and pyrene and cumulative content released from the analyzed sediment samples following root exudate rinsing decreased in the following order: citric acid > oxalic acid > malic acid. After elution, the total concentrations of phenanthrene and pyrene in sediment layers followed a descending order of bottom (9-12 cm) > middle (5-7 cm) > top (0-3 cm). Furthermore, a positive correlation between leachate pH values and PAH concentrations of the leachate was found. Consequently, the addition of root exudates can increase the leachability and bioavailability of phenanthrene and pyrene.

  6. Uptake and elimination of (9-/sup 14/C)phenanthrene in the turkey wing mussel (Arca zebra)

    SciTech Connect

    Solbakken, J.E.; Knap, A.H.; Searle, C.E.; Palmork, K.H.

    1983-04-01

    Turkey wing mussels of both sexes were collected from Harrington Sound, Bermuda and dosed after a week-long acclimation period with (9-/sup 14/C)phenanthrene (714 MBq/mmol). They were transferred into 8 liters of seawater containing 8 ..mu..g of labelled phenanthrene. Results show that the accumulation of labelled phenanthrene in the turkey wing mussel was very low compared to that found in other species. In the hepatopancreas, the uptake of phenanthrene based on the water concentration was only 4% of the corresponding value found in the calico clam (Macrocallista maculata) inhabiting the same area. In comparison, the uptake of phenanthrene in a temperate mollusc such as the horse mussel (Modiola modiolus) was also considerably higher than in the turkey wing (approx. 4 times). It therefore seems likely that these are due to species variations rather than environmental variations between subtropical and temperate areas. (JMT)

  7. Effect of microbial polymers on the sorption and transport of phenanthrene in a low-carbon sand

    SciTech Connect

    Dohse, D.M.; Lion, L.W. )

    1994-04-01

    Extracellular polymers of bacterial origin were analyzed for their effect on the sorption behavior of phenanthrene on a low-carbon aquifer sand. Batch experiments indicated that 85% of the polymers tested acted to decrease the distribution coefficient. Column experiments revealed a decrease in the retardation factor of phenanthrene by approximately 40% in the presence of an extracellular polymer produced by a Gram-negative motile rod isolated from a coal tar waste site. This polymer did not, however, influence the mineralization of phenanthrene and was not rapidly degraded by a mixed culture. The combination of the ability of the polymer to influence phenanthrene transport as well as its apparent persistence and lack of a negative effect on phenanthrene degradation suggest the extracellular polymers can act as agents that enhance PAH transport in natural systems. 50 refs., 8 figs., 2 tabs.

  8. Toxicity of sediment-associated pyrene and phenanthrene to Limnodrilus hoffmeisteri (Oligochaeta: Tubificidae)

    SciTech Connect

    Lotufo, G.R.; Fleeger, J.W.

    1996-09-01

    Acute and sublethal toxicities of sediment-spiked pyrene and phenanthrene to Limnodrilus hoffmeisteri Cleparede were investigated. Phenanthrene was acutely toxic at high sediment concentrations (10-d median lethal concentration of 297.5 {micro}g g{sup {minus}1}; 252.2--348.3, 95% confidence interval [Cl]). Pyrene was not acutely toxic, even at concentrations as high as 841 {micro}g g{sup {minus}1}. A significant impact of pyrene and phenanthrene on the feeding activity of L. hoffmeisteri was demonstrated through daily collection of egested fecal material during 5- and 10-d experiments. A short (5-d) exposure detected toxic effects more efficiently than a 10-d exposure, yielding IC25 values (estimated concentration causing a 25% reduction of measured endpoint in relation to the control[s]) of 58.9 {micro}g g{sup {minus}1} (32.1--89.4, 95% CI) for pyrene and 28.4 {micro}g g{sup {minus}1} (10.0--41.3, 95% CI) for phenanthrene. Effects on burrowing behavior and reproduction were assessed in a 28-d sediment exposure. Low burrowing avoidance (< 25%) was detected in high phenanthrene concentrations (143--612 {micro}g g{sup {minus}1}) but was not detected with pyrene. Offspring production was significantly reduced in dosed sediments yielding IC25 values of 59.1 {micro}g g{sup {minus}1} (38.3--112.5, 95% CI) for pyrene and 40.5 {micro}g g{sup {minus}1} (12.1--165.5, 955 CI) for phenanthrene. Decreases in egestion rates in the presence of nonpolar contaminants should be quantified when investigating the effects of bioturbation by deposit feeders on the flux of contaminants from sediment into the water column.

  9. Phenanthrene-triggered Chlorosis is caused by elevated Chlorophyll degradation and leaf moisture.

    PubMed

    Shen, Yu; Li, Jinfeng; Gu, Ruochen; Yue, Le; Zhan, Xinhua; Xing, Baoshan

    2017-01-01

    Leaf is an important organ in responding to environmental stresses. To date, chlorophyll metabolism under polycyclic aromatic hydrocarbon (PAH) stress is still unclear. Here we reveal, for the first time, the chlorophyll metabolism of wheat seedling leaves in response to phenanthrene (a model PAH) exposure. In this study, the hydroponic experiment was employed, and the wheat seedlings were exposed to phenanthrene to observe the response at day 1, 3, 5, 7 and 9. Over the exposure time, wheat leaf color turns light. With the accumulation of phenanthrene, the concentrations of glutamate, 5-aminolevulinic acid, uroporphyrinogen III, protoporphyrin IX, Mg-protoporphyrin IX and protochlorophyllide increase while the concentrations of porphobilinogen and Chlorophyll b decrease. Also chlorophyll a content rises initially and then declines. Uroporphyrinogen III synthase and chlorophyllase are activated and porphobilinogen deaminase activity declines in the treatments. Both chlorophyll synthesis and degradation are enhanced, but the degradation rate is faster. Phenanthrene accumulation has significant and positive effects on increase of glutamate, 5-aminolevulinic acid, uroporphyrinogen III, protoporphyrin IX, Mg-protoporphyrin IX and protochlorophyllide concentrations. There is a negative correlation between phenanthrene accumulation and total chlorophyll. Additionally, the leaf moisture increases. Therefore, it is concluded that wheat leaf chlorosis results from a combination of accelerated chlorophyll degradation and elevated leaf moisture under phenanthrene exposure. Our results are helpful not only for better understanding the toxicity of PAHs to plants and crop PAH-adaptive mechanism in the environment, but also for potentially employing the changes of the chlorophyll-synthesizing precursors and enzyme activities in plant leaves as indicators of plant response to PAH pollution.

  10. Improving the simulation of vibrationally resolved electronic spectra of phenanthrene: A computational Investigation

    NASA Astrophysics Data System (ADS)

    Pang, Min; Yang, Pan; Shen, Wei; Li, Ming; He, Rongxing

    2015-05-01

    Based on the density functional theory and its time-dependent extension, the properties of the ground and the first excited states of phenanthrene were calculated. In harmonic and anharmonic approximations, the well-resolved absorption and emission spectra of phenanthrene were simulated using the Franck-Condon approximation combined with the Herzberg-Teller and Duschinsky effects, and the results reproduced the experimental spectra very well. The mirror symmetry breakdown between absorption and emission spectra is induced mainly from the Herzberg-Teller effect and Duschinsky mode mixing. Moreover, most of the vibrational modes were tentatively assigned and compared with the experiment.

  11. Enantiomeric composition of the trans-dihydrodiols produced from phenanthrene by fungi

    SciTech Connect

    Sutherland, J.B.; Fu, P.P.; Von Tungeln, L.S.; Cerniglia, C.E. ); Yang, S.K. ); Casillas, R.P.; Crow, S.A. )

    1993-07-01

    Phenanthrene and other polycyclic aromatic hydrocarbons (PAHs) are widespread environmental pollutants. PAHs are frequently bioaccumulated by animals and can be activated to mutagenic and carcinogenic metabolites, but they are resistant to biodegradation by microorganisms. Although PAHs do not generally serve as carbon or energy sources for fungi, many fungi cometabolize one or more PAHs to trans-dihydrodiols. In this study, circular dichroism spectroscopy and chiral stationary-phase high-performance liquid chromatography is used to compare the stereoselectivity of three species of fungi that metabolize phenanthrene to trans-dihydrodiols, Cunninghamella elegans, Syncephalastrum racemosum, and Phanerochaete chrysosporium. 30 refs., 5 figs., 1 tab.

  12. Interaction of humic acids and humic-acid-like polymers with herpes simplex virus type 1

    NASA Astrophysics Data System (ADS)

    Klöcking, Renate; Helbig, Björn

    The study was performed in order to compare the antiviral activity against herpes simplex virus type 1 (HSV-1) of synthetic humic-acid-like polymers to that of their low-molecular-weight basic compounds and naturally occurring humic acids (HA) in vitro. HA from peat water showed a moderate antiviral activity at a minimum effective concentration (MEC) of 20 µg/ml. HA-like polymers, i.e. the oxidation products of caffeic acid (KOP), hydrocaffeic acid (HYKOP), chlorogenic acid (CHOP), 3,4-dihydroxyphenylacetic acid (3,4-DHPOP), nordihydroguaretic acid (NOROP), gentisinic acid (GENOP), pyrogallol (PYROP) and gallic acid (GALOP), generally inhibit virus multiplication, although with different potency and selectivity. Of the substances tested, GENOP, KOP, 3,4-DHPOP and HYKOP with MEC values in the range of 2 to 10 µg/ml, proved to be the most potent HSV-1 inhibitors. Despite its lower antiviral potency (MEC 40 µg/ml), CHOP has a remarkable selectivity due to the high concentration of this polymer that is tolerated by the host cells (>640 µg/ml). As a rule, the antiviral activity of the synthetic compounds was restricted to the polymers and was not preformed in the low-molecular-weight basic compounds. This finding speaks in favour of the formation of antivirally active structures during the oxidative polymerization of phenolic compounds and, indirectly, of corresponding structural parts in different HA-type substances.

  13. Different effects of copper (II), cadmium (II) and phosphate on the sorption of phenanthrene on the biomass of cyanobacteria.

    PubMed

    Tao, Yuqiang; Li, Wei; Xue, Bin; Zhong, Jicheng; Yao, Shuchun; Wu, Qinglong

    2013-10-15

    Due to the large surface area and high organic carbon content of cyanobacteria, organic contaminants can be readily sorbed on cyanobacteria during algal blooms, and then be transferred to the food web. This process is likely to be affected by the coexisting metals and nutrients, however, the possible impacts remain unclear. Effects of Cu(2+), Cd(2+), and phosphate on the sorption of phenanthrene on cyanobacterial biomass collected from an algal bloom were therefore studied. Continuous decrease in phenanthrene sorption was observed in the presence of low concentrations of Cu(2+), and Cd(2+) (<0.04 mmol L(-1)), because Cu(2+) and Cd(2+) were coadsorbed with phenanthrene on the surface of cyanobacteria as suggested by scanning electron microscopy-energy dispersive X-ray (SEM-EDX) and Fourier transform infrared (FTIR) analyses. Phenanthrene sorption began to increase with the further increase in Cu(2+) concentration, but remained lower than that in the absence of Cu(2+). This increase in sorption was ascribed to the cation-π interaction between Cu(2+) and phenanthrene, as suggested by the enhanced ultraviolet absorbance at 251 nm. In contrast, sorption rebounding of phenanthrene did not occur in the presence of higher concentrations of Cd(2+). The different effects of Cu(2+) and Cd(2+) on phenanthrene sorption were attributed to that Cd(2+) required much more energy than Cu(2+) to form cation-π complexes with phenanthrene in the solutions. Phenanthrene sorption decreased continuously with the increase in phosphate concentration. Phosphate blocked the binding sites, modified the cell morphology, and increased the negative charge as well as the hydrophilicity of the cyanobacterial surface, thereby suppressing phenanthrene sorption. This study indicates that sorption of aromatic organic compounds by cyanobacteria could be significantly alerted by concentrations and properties of the coexisting transition metals and phosphates, which may subsequently affect their

  14. The EmhABC efflux pump decreases the efficiency of phenanthrene biodegradation by Pseudomonas fluorescens strain LP6a.

    PubMed

    Adebusuyi, Abigail A; Smith, Angela Y; Gray, Murray R; Foght, Julia M

    2012-08-01

    Pseudomonas fluorescens strain LP6a, designated here as strain WEN (wild-type PAH catabolism, efflux positive), utilizes the polycyclic aromatic hydrocarbon phenanthrene as a carbon source but also extrudes it into the extracellular medium using the efflux pump EmhABC. Because phenanthrene is considered a nontoxic carbon source for P. fluorescens WEP, its energy-dependent efflux seems counter-productive. We hypothesized that the efflux of phenanthrene would decrease the efficiency of its biodegradation. Indeed, an emhB disruptant strain, wild-type PAH catabolism, efflux negative (WEN), biodegraded 44% more phenanthrene than its parent strain WEP during a 6-day incubation. To determine whether efflux affected the degree of oxidation of phenanthrene, we quantified the conversion of ¹⁴C-phenanthrene to radiolabeled polar metabolites and ¹⁴CO₂. The emhB⁻ WEN strain produced approximately twice as much ¹⁴CO₂ and radiolabeled water-soluble metabolites as the WEP strain. In contrast, the mineralization of ¹⁴C-glucose, which is not a known EmhB efflux substrate, was equivalent in both strains. An early open-ring metabolite of phenanthrene, trans-4-(1-hydroxynaphth-2-yl)-2-oxo-3-butenoic acid, also was found to be a substrate of the EmhABC pump and accumulated in the supernatant of WEP but not WEN cultures. The analogous open-ring metabolite of dibenzothiophene, a heterocyclic analog of phenanthrene, was extruded by EmhABC plus a putative alternative efflux pump, whereas the end product 3-hydroxy-2-formylbenzothiophene was not actively extruded from either WEP or WEN cells. These results indicate that the active efflux of phenanthrene and its early metabolite(s) decreases the efficiency of phenanthrene degradation by the WEP strain. This activity has implications for the bioremediation and biocatalytic transformation of polycyclic aromatic hydrocarbons and heterocycles.

  15. Potentiometric titration and equivalent weight of humic acid

    USGS Publications Warehouse

    Pommer, A.M.; Breger, I.A.

    1960-01-01

    The "acid nature" of humic acid has been controversial for many years. Some investigators claim that humic acid is a true weak acid, while others feel that its behaviour during potentiometric titration can be accounted for by colloidal adsorption of hydrogen ions. The acid character of humic acid has been reinvestigated using newly-derived relationships for the titration of weak acids with strong base. Re-interpreting the potentiometric titration data published by Thiele and Kettner in 1953, it was found that Merck humic acid behaves as a weak polyelectrolytic acid having an equivalent weight of 150, a pKa of 6.8 to 7.0, and a titration exponent of about 4.8. Interdretation of similar data pertaining to the titration of phenol-formaldehyde and pyrogallol-formaldehyde resins, considered to be analogs for humic acid by Thiele and Kettner, leads to the conclusion that it is not possible to differentiate between adsorption and acid-base reaction for these substances. ?? 1960.

  16. FLUORESCENCE CHARACTERIZATION OF IHSS HUMIC SUBSTANCES: TOTAL LUMINESCENCE SPECTRA WITH ABSORBANCE CORRECTION. (R822251)

    EPA Science Inventory

    Total luminescence spectroscopy was applied to the fluorescence characterization of humic substances obtained from the International Humic Substances Society (IHSS). Results show that total luminescence spectra, represented as excitation-emission matrices (EEMs), may be used to d...

  17. QUANTITATIVE FOURIER TRANSFORM INFRARED SPECTROSCOPIC INVESTIGATION OF HUMIC SUBSTANCE FUNCTIONAL GROUP COMPOSITION

    EPA Science Inventory

    Infrared (IR) spectroscopy has been widely used for the structural investigation of humic substances. Although Fourier Transform Infrared (FTIR) instrumentation has been available for sometime, relatively little work with these instruments has been reported for humic substances,...

  18. INFLUENCE OF BORATE BUFFERS ON THE ELECTROPHORETIC BEHAVIOR OF HUMIC SUBSTANCES IN CAPILLARY ZONE ELECTROPHORESIS

    EPA Science Inventory

    The influence of tetrahydroxyborate ions on the electrophoretic mobility of humic acids was evaluated by capillary electrophoresis (CE). Depending on the molarity of borate ions in the separation buffer, the humic acids exhibit electropherograms with sharp peaks consistently exte...

  19. Binding of pyrene to aquatic and commercial humic substances: The role of molecular weight and aromaticity

    USGS Publications Warehouse

    Chin, Y.-P.; Aiken, G.R.; Danielsen, K.M.

    1997-01-01

    The binding of pyrene to a number of humic substances isolated from various aquatic sources and a commercial humic acid was measured using the solubility enhancement method. The humic materials used in this study were characterized by various spectroscopic and liquid chromatography methods. A strong correlation was observed between the pyrene binding coefficient, K(doc), and the molecular weights, molar absorptivities at 280 nm, and aromaticity of the aquatic humic substances. Binding of pyrene to the commercial humic acid, however, was significantly stronger and did not obey the relationships observed between K(doc) and the chemical properties of the aquatic humic substrates. These results suggest that the molecular weight and the aromatic content of the humic substrates exert influences on the binding of nonpolar and planar aromatic molecules and that the physicochemical properties of both humic materials and organic solutes are important in controlling the speciation of nonpolar organic contaminants in natural waters.

  20. Syntheses and Chemosensory of Anthracene and Phenanthrene Bisimide Derivatives

    NASA Technical Reports Server (NTRS)

    Bogusz, Zachary A.

    2004-01-01

    As the present technology of biochemical weapons advances, it is essential for science to attempt to prepare our nation for such an occurrence. Various areas of current research are devoted to precautionary measures and potential antidotes for national security. A practical application of these precautions would be the development of a chemical capable of detecting harmful gas. The benefits of being capable to synthesis a chemical compound that would warn and identify potentially deadly gases would ensure a higher level of safety. The chemicals in question can be generalized as bisimide anthracene derivatives. The idea behind these compounds is that in the presence of certain nerve gases, the compound will actually fluoresce, giving an indication that there is a strong likelihood of the presence of a nerve gas and ensure the proper precautionary measures are taken. The fluorescence is due to the quenching of an electric proton transfer within the structure of the molecule. The system proves to be very unique on account of the fact that the fluorescence can be "turned off" by reducing the system. By utilizing the synthesis designed by Dr. Faysal Ilhan, four distinct compounds can be synthesized through photochemical reactions involving para- and ortho- diketones. The photochemistry involved is very modem and much research is being devoted to fully understanding the possibilities and alternative applications of such materials. and meta-nitro anthracene bisimide (ABI-NO2), the amine of each (ABI-NH2), a para- and meta-nitro phenanthrene bisimjde (PBI-NO2), and the amine of each (PBI-NH2). Upon synthesizing these distinct compounds, I must then purify and analyze them in order to obtain any relevant trends, behaviors, and characteristics. The chemical composition analyses that will be conducted are the procedures taken by Dr. Daniel Tyson on previous experiments. The results generated from the data will point further research in the correct direction and hopefully

  1. Chlorination of humic materials: Byproduct formation and chemical interpretations

    USGS Publications Warehouse

    Reckhow, D.A.; Singer, P.C.; Malcolm, R.L.

    1990-01-01

    Ten aquatic humic and fulvic acids were isolated and studied with respect to their reaction with chlorine. Yields of TOX, chloroform, trichloroacetic acid, dichloroacetic acid, dichloroacetonitrile, and 1,1,1-trichloropropanone were measured at pH 7 and 12. Humic acids produced higher concentrations than their corresponding fulvic acids of all byproducts except 1,1,1-trichloropropanone. Chlorine consumption and byproduct formation were related to fundamental chemical characteristics of the humic materials. A statistical model was proposed for activated aromatic content based on 13C NMR and base titration data. The values estimated from this model were found to be well correlated with chlorine consumption. Specific byproduct formation was related to UV absorbance, nitrogen content, or the activated aromatic content. ?? 1990 American Chemical Society.

  2. Chemical modeling of boron adsorption by humic materials using the constant capacitance model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The constant capacitance surface complexation model was used to describe B adsorption behavior on reference Aldrich humic acid, humic acids from various soil environments, and dissolved organic matter extracted from sewage effluents. The reactive surface functional groups on the humic materials wer...

  3. Crop growth and production responses to commercial humic products in U.S. Midwestern rainfed conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Humic products (humic and/or fulvic acids) have been in use for over 100 years, yet published research is scant on crop responses to humics under differing soil and weather conditions. We initiated field research experiments on corn (Zea mays L.) in Iowa in 2009 and have since expanded to multiple U...

  4. Risks of single-walled carbon nanotubes acting as contaminants-carriers: potential release of phenanthrene in Japanese medaka (Oryzias latipes).

    PubMed

    Su, Yu; Yan, Xiaomin; Pu, Yubing; Xiao, Feng; Wang, Dongsheng; Yang, Min

    2013-05-07

    The performance of carbon nanotubes (CNTs) acting as contaminants-carriers in vivo is critical for understanding the environmental risks of CNTs. In this study, the whole-body accumulation and tissue distribution of phenanthrene in Japanese medaka was examined in the presence of single-walled carbon nanotubes (SWCNTs) and the potential release of phenanthrene was investigated from two types of SWCNTs suspensions that differed in surface charge and stability. The results showed that the coexistence of SWCNTs facilitated the accumulation of phenanthrene in the digestive track of fish and therefore enhanced the whole-body phenanthrene concentration by 2.1 fold after exposure for 72 h. Meanwhile, 6.4-48 and 20-34 times higher phenanthrene concentrations were measured in the liver and brain of fish exposure to the two mixtures, respectively, when comparing with the phenanthrene alone treatment with equal concentration of soluble phenanthrene. The extra phenanthrene was from the SWCNTs-associated phenanthrene that accumulated in the digestive track indicating the release of phenanthrene from SWCNTs did occur in fish. Moreover, the neutrally charged SWCNTs showed different agglomeration behaviors from the negatively charged SWCNTs, which could affect the accumulation of SWCNTs in the digestive track of fish and subsequently influence the retention of phenanthrene associated with the carbon nanotubes.

  5. Effects of humic acids on the growth of bacteria

    NASA Astrophysics Data System (ADS)

    Tikhonov, V. V.; Yakushev, A. V.; Zavgorodnyaya, Yu. A.; Byzov, B. A.; Demin, V. V.

    2010-03-01

    The influence of humic acids of different origins on the growth of bacterial cultures of different taxa isolated from the soil and the digestive tracts of earthworms ( Aporrectodea caliginosa)—habitats with contrasting conditions—was studied. More than half of the soil and intestinal isolates from the 170 tested strains grew on the humic acid of brown coal as the only carbon source. The specific growth rate of the bacteria isolated from the intestines of the earthworms was higher than that of the soil bacteria. The use of humic acids by intestinal bacteria confirms the possibility of symbiotic digestion by earthworms with the participation of bacterial symbionts. Humic acids at a concentration of 0.1 g/l stimulated the growth of the soil and intestinal bacteria strains (66 strains out of 161) on Czapek’s medium with glucose (1 g/l), probably, acting as a regulator of the cell metabolism. On the medium with the humic acid, the intestinal bacteria grew faster than the soil isolates did. The most active growth of the intestinal isolates was observed by Paenibacillus sp., Pseudomonas putida, Delftia acidovorans, Microbacterium terregens, and Aeromonas sp.; among the soil ones were the representatives of the Pseudomonas genus. A response of the bacteria to the influence of humic acids was shown at the strain level using the example of Pseudomonas representatives. The Flexom humin preparation stimulated the growth of the hydrocarbon-oxidizing Acinetobacter sp. bacteria. This effect can be used for creating a new compound with the elevated activity of bacteria that are destroyers of oil and oil products.

  6. COSOLVENT EFFECTS ON PHENANTHRENE SORPTION-DESORPTION ON A FRESH-WATER SEDIMENT

    EPA Science Inventory

    This study evaluated the effects of the water-miscible cosolvent methanol on the sorption-desorption of phenanthrene by the natural organic matter (NOM) of a fresh-water sediment. A biphasic pattern was observed in the relationship between the log of the carbon-normalized sorpti...

  7. Crystal structure search and electronic properties of alkali-doped phenanthrene and picene

    NASA Astrophysics Data System (ADS)

    Naghavi, S. Shahab; Tosatti, Erio

    2014-08-01

    Alkali-doped aromatic compounds have shown evidence of metallic and superconducting phases whose precise nature is still mysterious. In potassium and rubidium-doped phenanthrene, superconducting temperatures around 5 K have been detected, but such basic elements as the stoichiometry, crystal structure, and electronic bands are still speculative. We seek to predict the crystal structure of M3-phenanthrene (M = K, Rb) using ab initio evolutionary simulation in conjunction with density functional theory (DFT), and find metal but also insulator phases with distinct structures. The original P21 herringbone structure of the pristine molecular crystal is generally abandoned in favor of different packing and chemical motifs. The metallic phases are frankly ionic with three electrons acquired by each molecule. In the nonmagnetic insulating phases the alkalis coalesce reducing the donated charge from three to two per phenanthrene molecule. A similar search for K3-picene yields an old and a new structure, with unlike potassium positions and different electronic bands, but both metallic retaining the face-to-edge herringbone structure and the P21 symmetry of pristine picene. Both the new K3-picene and the best metallic M3-phenanthrene are further found to undergo a spontaneous transition from metal to antiferromagnetic insulator when spin polarization is allowed, a transition which is not necessarily real, but which underlines the necessity to include correlations beyond DFT. Features of the metallic phases that may be relevant to phonon-driven superconductivity are underlined.

  8. Strain in strain-free benzenoid hydrocarbons: The case of phenanthrene

    NASA Astrophysics Data System (ADS)

    Radenković, Slavko; Gutman, Ivan; Đorđević, Slađana

    2015-04-01

    Benzenoid molecules possessing bays are traditionally considered as 'strain-free'. Yet, repulsion between the two bay H-atoms affects the length of the near-lying carbon-carbon bonds. A method is developed to estimate the energy of this strain. In the case of phenanthrene its value was found to be about 7 kJ/mol.

  9. Preparation and characterization of a novel graphene/biochar composite for aqueous phenanthrene and mercury removal.

    PubMed

    Tang, Jingchun; Lv, Honghong; Gong, Yanyan; Huang, Yao

    2015-11-01

    A graphene/biochar composite (G/BC) was synthesized via slow pyrolysis of graphene (G) pretreated wheat straw, and tested for the sorption characteristics and mechanisms of representative aqueous contaminants (phenanthrene and mercury). Structure and morphology analysis showed that G was coated on the surface of biochar (BC) mainly through π-π interactions, resulting in a larger surface area, more functional groups, greater thermal stability, and higher removal efficiency of phenanthrene and mercury compared to BC. Pseudo second-order model adequately simulated sorption kinetics, and sorption isotherms of phenanthrene and mercury were simulated well by dual-mode and BET models, respectively. FTIR and SEM analysis suggested that partitioning and surface sorption were dominant mechanisms for phenanthrene sorption, and that surface complexation between mercury and C-O, CC, -OH, and OC-O functional groups was responsible for mercury removal. The results suggested that the G/BC composite is an efficient, economic, and environmentally friendly multifunctional adsorbent for environmental remediation.

  10. Bioremediation enhancement of phenanthrene contaminated soils by chemical pre-oxidation

    SciTech Connect

    Van Kemenade, I.; Anderson, W.A.; Scharer, J.M.; Moo-Young, Murray

    1995-12-31

    A two-step oxidation process was investigated for the treatment of phenanthrene contaminated soil fines (particle diameter {le}63 {mu}m) resulting from a soil washing process. Oxone{reg_sign} (2KHSO{sub 5}{center_dot}KHSO{sub 4}{center_dot}K{sub 2}SO{sub 4}) and hydrogen peroxide (H{sub 2}O{sub 2}) were used as oxidants for the chemical pre-oxidation step and unacclimatized municipal activated sludge was employed in the subsequent biodegradation step. Oxone was found to have an oxidation efficiency approximately ten-fold greater than hydrogen peroxide on a stoichiometric basis. In comparison to chemical oxidation only, a 24 hour pre-oxidation step using 5 and 10 g/L Oxone followed by a 5 day biological oxidation step enhanced removal of phenanthrene from the soil by 115% and 32%, respectively. Similarly, a 48 hour pre-oxidation step utilizing 5 and 10 g/L Oxone followed by a 5 day biological oxidation step enhanced the removal of phenanthrene from the soil by 113% and 43%, respectively. Based on this preliminary assessment, a treatment protocol that integrates a 24 hour chemical preoxidation step with 5 g/L Oxone followed by a 5 day biological oxidation step appears to be an effective combination for the remediation of this phenanthrene contaminated soil. 21 refs., 4 figs., 2 tabs.

  11. Novel Phenanthrene-Degrading Bacteria Identified by DNA-Stable Isotope Probing.

    PubMed

    Jiang, Longfei; Song, Mengke; Luo, Chunling; Zhang, Dayi; Zhang, Gan

    2015-01-01

    Microorganisms responsible for the degradation of phenanthrene in a clean forest soil sample were identified by DNA-based stable isotope probing (SIP). The soil was artificially amended with either 12C- or 13C-labeled phenanthrene, and soil DNA was extracted on days 3, 6 and 9. Terminal restriction fragment length polymorphism (TRFLP) results revealed that the fragments of 219- and 241-bp in HaeIII digests were distributed throughout the gradient profile at three different sampling time points, and both fragments were more dominant in the heavy fractions of the samples exposed to the 13C-labeled contaminant. 16S rRNA sequencing of the 13C-enriched fraction suggested that Acidobacterium spp. within the class Acidobacteria, and Collimonas spp. within the class Betaproteobacteria, were directly involved in the uptake and degradation of phenanthrene at different times. To our knowledge, this is the first report that the genus Collimonas has the ability to degrade PAHs. Two PAH-RHDα genes were identified in 13C-labeled DNA. However, isolation of pure cultures indicated that strains of Staphylococcus sp. PHE-3, Pseudomonas sp. PHE-1, and Pseudomonas sp. PHE-2 in the soil had high phenanthrene-degrading ability. This emphasizes the role of a culture-independent method in the functional understanding of microbial communities in situ.

  12. Relationship between organic matter content of soil and the sequestration of phenanthrene

    SciTech Connect

    Nam, K.; Chung, N.; Alexander, M.

    1998-12-01

    A study was conducted to determine the relationship between organic matter content of soil and the availability of aged phenanthrene. Phenanthrene was aged for 200 days in sterile samples of dissimilar soils, soils treated with H{sub 2}O{sub 2} to reduce the content of organic matter, and sand. Sequestration as measured by the extent of mineralization of phenanthrene by an added bacterium was appreciable in samples with >2.0% organic C, and the bioavailability of the hydrocarbon declined with time of aging. Sequestration was not evident in soils or sand with <2.0% organic C. Phenanthrene aged for 200 days was more slowly degraded than the freshly added compound in soils with >2.0% organic C, but a small effect on rate was evident in soil and sand with <2.0% organic C. More of the compound remained after biodegradation of the hydrocarbon aged for 200 days than if it was not aged, with the largest amount remaining in soils with >2.0% organic C and the least in sand. Aging as measured by a decline in extractability of 1-butanol was evident in all soils, although the rate was fastest in soil with >2.0% organic C. The volume occupied by pores of <10-{micro}m diameter was higher in soils containing more organic matter and was negligible in sand. The authors suggest that the organic matter content of soil is a major determinant of sequestration.

  13. Calcium-mediated modulation of Pseudomonas mendocina NR802 biofilm influences the phenanthrene degradation.

    PubMed

    Mangwani, Neelam; Shukla, Sudhir K; Rao, T Subba; Das, Surajit

    2014-02-01

    A potential biofilm forming and phenanthrene utilizing marine bacterium Pseudomonas mendocina NR802 was isolated from Rushukulya, Odisha, East Coast of India. The effect of Ca(2+) and Mg(2+) on biofilm growth and phenanthrene degradation was evaluated. Among the various tested concentrations, 20 mM of Ca(2+) and Mg(2+) showed a significant enhancement in biofilm production by the bacterium. The SEM-EDAX study showed that the elemental composition of the biofilm varied significantly when grown in the presence of Ca(2+) and Mg(2+). The CSLM analysis of biofilms grown in the presence of 20 mM Ca(2+) and Mg(2+) reveal the critical role of these ions on biofilm architectural parameters such as total biomass, biofilm thickness, roughness coefficient and surface to biovolume ratio. Ca(2+) was found to enhance the extracellular polymeric substances (EPS) production and phenanthrene degradation. Ca(2+) enhanced the biofilm growth in a dose dependent manner, whereas Mg(2+) significantly increased the cell growth in biofilm. More than 15% increase in phenanthrene degradation was observed when biofilm was grown in the presence of an additional 20 mM Ca(2+). This study also supports the fundamental role of Ca(2+) in biofilm growth, architecture as well as biofilm-mediated pollutant degradation.

  14. Biodegradation of Phenanthrene by Pseudomonas sp. JPN2 and Structure-Based Degrading Mechanism Study.

    PubMed

    Jin, Jingnan; Yao, Jun; Zhang, Qingye

    2016-11-01

    The strain Pseudomonas sp. JPN2 had a high potential to degrade phenanthrene degrading 98.52 % of the initial amount of 100 mg L(-1) after 10 days incubation. The analysis of metabolites demonstrated that the cleavage of phenanthrene started at the C9 and C10 positions on the aromatic ring by the dioxygenation reaction, and then further degraded via a phthalate pathway. To understand the interaction between phenanthrene and the amino acid residues in the active site of the target enzyme, a molecular docking simulation was performed. The results showed that the distances of C9-O1 and C10-O2 atoms were 3.47 and 3.67 Å, respectively. The C9 and C10 positions of the phenanthrene ring are much closer to the dioxygen molecule in the active site relative to the other atoms. Therefore, the C9 and C10 positions are vulnerable to attack in the initial oxygenation process.

  15. Effect of surfactant on phenanthrene metabolic kinetics by Citrobacter sp. SA01.

    PubMed

    Li, Feng; Zhu, Lizhong; Zhang, Dong

    2014-11-01

    To attain a better understanding of the effects of surfactants on the metabolic kinetics of hydrophobic organic compounds, the biodegradation of phenanthrene by Citrobacter sp. SA01 was investigated in a batch experiment containing Tween 80, sodium dodecyl benzene sulfonate and liquid mineral salt medium. The Monod model was modified to effectively describe the partition, phenanthrene biodegradation and biopolymer production. The results showed that Tween 80 and sodium dodecyl benzene sulfonate (each at 50mg/L) enhanced phenanthrene metabolism and poly-β-hydroxybutyrate production as indicated by the increasing amounts of intermediates (by 17.2% to 47.9%), and percentages of poly-β-hydroxybutyrate (by 107.3% and 33.1%) within the cell dry weight when compared to their absence. The modified Monod model was capable of predicting microbial growth, phenanthrene depletion and biopolymer production. Furthermore, the Monod kinetic coefficients were largely determined by the surfactant-enhanced partition, suggesting that partitioning is a critical process in surfactant-enhanced bioremediation of hydrophobic organic compounds.

  16. Fluorene and Phenanthrene Uptake and Accumulation by Wheat, Alfalfa and Sunflower from the Contaminated Soil.

    PubMed

    Salehi-Lisar, Seyed Yahya; Deljoo, Somaye; Harzandi, Ahmad Mosen

    2015-01-01

    Polycyclic Aromatic Hydrocarbons (PAHs) are diverse organic contaminants released into the environment by both natural and anthropogenic activities. These compounds have negative impacts on plants growth and development. Although there are many reports on their existence in different parts of plant, their uptake and translocation pathways and mechanisms are not well understood yet. This paper highlights the uptake, translocation and accumulation of PAHs by wheat, sunflower and alfalfa through an experimental study under controlled conditions. Seeds were cultivated in a soil containing 50 mg/kg of phenanthrene and fluorene and their concentrations in plants roots and shoots were determined using a gas chromatograph after 7 and 14 days. The results showed that phenanthrene and fluorene concentrations in the treated plants were increased over the time. PAHs bioavailability was time and species dependent and generally, phenanthrene uptake and translocation was faster than that of fluorene, probably due to their higher Kow. Fluorene tended to accumulate in roots, but phenanthrene was transported to aerial parts of plants.

  17. Photooxygenation of alkynylperylenes. Formation of dibenzo[jk,mn]phenanthrene-4,5-diones.

    PubMed

    Maeda, Hajime; Nanai, Yasuaki; Mizuno, Kazuhiko; Chiba, Junya; Takeshima, Sakiko; Inouye, Masahiko

    2007-11-09

    3-(1-Alkynyl)perylenes undergo oxygenation when subjected to irradiation with visible light under aerated conditions. The structures of novel oxygenated products formed in this manner are assigned as regioisomeric dibenzo[jk,mn]phenanthrene-4,5-diones.

  18. Remediation of phenanthrene-contaminated soil by simultaneous persulfate chemical oxidation and biodegradation processes.

    PubMed

    Mora, Verónica C; Madueño, Laura; Peluffo, Marina; Rosso, Janina A; Del Panno, María T; Morelli, Irma S

    2014-06-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous compounds with carcinogenic and/or mutagenic potential. To address the limitations of individual remediation techniques and to achieve better PAH removal efficiencies, the combination of chemical and biological treatments can be used. The degradation of phenanthrene (chosen as a model of PAH) by persulfate in freshly contaminated soil microcosms was studied to assess its impact on the biodegradation process and on soil properties. Soil microcosms contaminated with 140 mg/kgDRY SOIL of phenanthrene were treated with different persulfate (PS) concentrations 0.86-41.7 g/kgDRY SOIL and incubated for 28 days. Analyses of phenanthrene and persulfate concentrations and soil pH were performed. Cultivable heterotrophic bacterial count was carried out after 28 days of treatment. Genetic diversity analysis of the soil microcosm bacterial community was performed by PCR amplification of bacterial 16S rDNA fragments followed by denaturing gradient gel electrophoresis (DGGE). The addition of PS in low concentrations could be an interesting biostimulatory strategy that managed to shorten the lag phase of the phenanthrene biological elimination, without negative effects on the physicochemical and biological soil properties, improving the remediation treatment.

  19. Bacterial mineralization of phenanthrene on thermally activated palygorskite: A (14)C radiotracer study.

    PubMed

    Biswas, Bhabananda; Sarkar, Binoy; Naidu, Ravi

    2017-02-01

    Clay-bacterial interaction can significantly influence the biodegradation of organic contaminants in the environment. A moderate heat treatment of palygorskite could alter the physicochemical properties of the clay mineral and thus support the growth and function of polycyclic aromatic hydrocarbon (PAH)-degrading bacteria. By using (14)C-labelled phenanthrene and a model bacterium Burkholderia sartisoli, we studied the mineralization of phenanthrene on the surface of a moderately heat-treated (up to 400°C) palygorskite. The heat treatment at 400°C induced a reduction of binding sites (e.g., by the elimination of organic matter and/or channel shrinkage) in the palygorskite and thus imparted a weaker sequestration of phenanthrene on its surface and within the pores. As a result, a supplement with the thermally modified palygorskite (400°C) significantly increased (20-30%; p<0.05) the biomineralization of total phenanthrene in a simulated soil slurry system. These results are highly promising to develop a clay mineral based technology for the bioremediation of PAH contaminants in water and soil environments.

  20. Mechanistic Studies on the Dibenzofuran Formation from Phenanthrene, Fluorene and 9–Fluorenone

    PubMed Central

    Li, Shanqing; Zhang, Qingzhu

    2015-01-01

    We carried out molecular orbital theory calculations for the homogeneous gas‑phase formation of dibenzofuran from phenanthrene, fluorene, 9-methylfluorene and 9-fluorenone. Dibenzofuran will be formed if ∙OH adds to C8a, and the order of reactivity follows as 9-fluorenone > 9-methylfluorene > fluorene > phenanthrene. The oxidations initiated by ClO∙ are more favorable processes, considering that the standard reaction Gibbs energies are at least 21.63 kcal/mol lower than those of the equivalent reactions initiated by ∙OH. The adding of ∙OH and then O2 to phenanthrene is a more favorable route than adding ∙OH to C8a of phenanthrene, when considering the greater reaction extent. The reaction channel from fluorene and O2 to 9-fluorenone and H2O seems very important, not only because it contains only three elementary reactions, but because the standard reaction Gibbs energies are lower than −80.07 kcal/mol. PMID:25756381

  1. Novel Phenanthrene-Degrading Bacteria Identified by DNA-Stable Isotope Probing

    PubMed Central

    Luo, Chunling; Zhang, Dayi; Zhang, Gan

    2015-01-01

    Microorganisms responsible for the degradation of phenanthrene in a clean forest soil sample were identified by DNA-based stable isotope probing (SIP). The soil was artificially amended with either 12C- or 13C-labeled phenanthrene, and soil DNA was extracted on days 3, 6 and 9. Terminal restriction fragment length polymorphism (TRFLP) results revealed that the fragments of 219- and 241-bp in HaeIII digests were distributed throughout the gradient profile at three different sampling time points, and both fragments were more dominant in the heavy fractions of the samples exposed to the 13C-labeled contaminant. 16S rRNA sequencing of the 13C-enriched fraction suggested that Acidobacterium spp. within the class Acidobacteria, and Collimonas spp. within the class Betaproteobacteria, were directly involved in the uptake and degradation of phenanthrene at different times. To our knowledge, this is the first report that the genus Collimonas has the ability to degrade PAHs. Two PAH-RHDα genes were identified in 13C-labeled DNA. However, isolation of pure cultures indicated that strains of Staphylococcus sp. PHE-3, Pseudomonas sp. PHE-1, and Pseudomonas sp. PHE-2 in the soil had high phenanthrene-degrading ability. This emphasizes the role of a culture-independent method in the functional understanding of microbial communities in situ. PMID:26098417

  2. Simultaneous sorption of phosphate and phenanthrene to inorgano-organo-bentonite from water.

    PubMed

    Ma, Jianfeng; Zhu, Lizhong

    2006-08-25

    The nonbiodegradable organic pollutants and excess phosphate can not be effectively removed from municipal wastewater by the widely used bioprocess, thus they are harmful to aquatic environment. In this investigation, the feasibility of utilizing inorgano-organo-bentonite (IOB), which was bentonite mineral modified with both Fe polycations and cetyltrimethylammonium bromide (CTMAB), was explored to simultaneously remove phosphate and phenanthrene from water. The results showed that the IOB had strong affinity for both phosphate and polycyclic aromatic hydrocarbons (PAHs) such as phenanthrene in water. It was found that more than 95% phosphate and 99% phenanthrene were removed from water within 30 min. The sorption of phosphate on IOB proved to be an anion/OH(-) exchange reaction. Compared with organobentonite and bentonite mineral, the settlement separation of IOB from aquatic phase was greatly improved. The residual turbidity reached a minimum value of 10 nephelometric turbidity units (NTU) in 60 min. It was indicated that IOB is a favorable sorbent and can simultaneously remove nonbiodegradable organic pollutants such as phenanthrene and phosphate after the bioprocess in wastewater treatment.

  3. Biodegradation of phenanthrene using adapted microbial consortium isolated from petrochemical contaminated environment.

    PubMed

    Janbandhu, Anjali; Fulekar, M H

    2011-03-15

    In developing countries like India, there are many industrial areas discharging effluent containing large amount of polyaromatic hydrocarbon (PAH) which causes hazardous effect on the soil-water environment. The objective of this study was to isolate and characterize high-efficiency PAH-degrading microbial consortium from 3 decade old petrochemical refinery field located in Nagpur, Maharashtra with history of PAH disposal. Based on biochemical tests and 16S rDNA gene sequence analysis the consortium was identified as Sphingobacterium sp., Bacillus cereus and a novel bacterium Achromobacter insolitus MHF ENV IV with effective phenanthrene-degrading ability. The biodegradation data of phenanthrene indicates about 100%, 56.9% and 25.8% degradation at the concentration of 100mg/l, 250 mg/l and 500 mg/l respectively within 14 days. The consortium and its monoculture isolates also utilized variety of other hydrocarbons for growth. To best of our knowledge this is the first time that Achromobacter insolitus has been reported to mineralize phenanthrene effectively. GC-MS analysis of phenanthrene degradation confirmed biodegradation by detection of intermediates like salicylaldehyde, salicylic acid and catechol. All the results indicated that the microbial consortium have a promising application in bioremediation of petrochemical contaminated environments and could be potentially useful for the study of PAH degradation and for bioremediation purposes.

  4. Remediation of phenanthrene from contaminated kaolinite by electroremediation-Fenton technology.

    PubMed

    Alcantara, T; Pazos, M; Gouveia, S; Cameselle, C; Sanroman, M A

    2008-07-01

    Polycyclic aromatic hydrocarbons (PAHs) cause a high environmental impact when released into the environment. The objective of this study was to evaluate the capacity to decontaminate polluted soils with phenanthrene as a model PAH using a combination of two technologies: electrokinetic remediation and Fenton process. Kaolinite was used as a model sample that was artificially polluted at the laboratory at an initial concentration of phenanthrene of 500 mg kg(-1) of dried kaolinite. The standard electrokinetic process resulted in negligible removal of phenanthrene from the kaolinite sample. Faster and more efficient degradation of this compound can be promoted by introduction of a strong oxidant into the soil such as hydroxyl radicals. For this reason, the Fenton reactions have been induced in several experiments in which H(2)O(2) (10%) was used as flushing solution, and kaolinite polluted with iron was used. When anode and cathode chambers were filled with H(2)O(2) (10%), the kaolinite pH is maintained at an acid value around 3.5 without pH control and an overall removal and destruction efficiency of phenanthrene of 99% was obtained in 14 days by applying a voltage gradient of 3 V cm(-1). Therefore, it is evident that a combined technology of electrokinetic remediation and Fenton reaction is capable of simultaneously removing and degrading of PAHs in polluted model samples with kaolinite.

  5. Phenanthrene degradation by Pseudoxanthomonas sp. DMVP2 isolated from hydrocarbon contaminated sediment of Amlakhadi canal, Gujarat, India.

    PubMed

    Patel, Vilas; Cheturvedula, Sravanthi; Madamwar, Datta

    2012-01-30

    Amlakhadi canal, flowing through Ankleshwar (Gujarat, India) has been impinged with various xenobiotic compounds, released in industrial discharges, over last many decades. Twenty five bacterial strains capable of phenanthrene degradation were isolated from sediments of Amlakhadi canal. The best strain amongst them was identified as Pseudoxanthomonas sp. DMVP2 based on 16S rRNA gene sequence analysis, and selected for further studies. Experiments were carried out for optimization of abiotic parameters for efficient phenanthrene degradation. Strain DMVP2 was able to degrade 300 ppm of phenanthrene completely in minimal medium containing peptone (0.1%, w/v) as nitrogen source with initial pH 8.0 at 37°C under shaking condition (150 rpm) within 120 h. Strain DMVP2 was able to consume 1,600 mg/l of phenanthrene even at high initial concentration (4,000 mg/l) of phenanthrene. Identification of phthalic acid as major metabolite on GC-MS analysis and detection of protocatechuate dioxygenase activity revealed that phenanthrene was metabolized by phthalic acid-protocatechuate acid pathway. Strain DMVP2 was also able to utilize other xenobiotic compounds as sole carbon source and degrade phenanthrene in presence of other petroleum hydrocarbons. Consequently, Pseudoxanthomonas sp. DMVP2 has potential applications in bioremediation strategies.

  6. Low molecular weight species in humic and fulvic fractions

    USGS Publications Warehouse

    Wilson, M.A.; Collin, P.J.; Malcolm, R.L.; Perdue, E.M.; Cresswell, P.

    1988-01-01

    Fourier transform solution 1H nuclear magnetic resonance (NMR) spectrometry with homogated water peak irradiation is a useful method for detecting low molecular weight substances in humic extracts. Succinate, acetate, methanol, formate, lactate and some aryl methoxyl compounds have been detected in extracts from a wide range of sources. In view of the controversy over whether low molecular weight substances are contaminants in humic extracts introduced by the concentration procedure, we report that some of these materials are not contaminants since 1H-NMR can be used to follow their formation from higher molecular weight species. ?? 1988.

  7. Gene quantification by the NanoGene assay is resistant to inhibition by humic acids.

    PubMed

    Kim, Gha-Young; Wang, Xiaofang; Ahn, Hosang; Son, Ahjeong

    2011-10-15

    NanoGene assay is a magnetic bead and quantum dot nanoparticles based gene quantification assay. It relies on a set of probe and signaling probe DNAs to capture the target DNA via hybridization. We have demonstrated the inhibition resistance of the NanoGene assay using humic acids laden genomic DNA (gDNA). At 1 μg of humic acid per mL, quantitiative PCR (qPCR) was inhibited to 0% of its quantification capability whereas NanoGene assay was able to maintain more than 60% of its quantification capability. To further increase the inhibition resistance of NanoGene assay at high concentration of humic acids, we have identified the specific mechanisms that are responsible for the inhibition. We examined five potential mechanisms with which the humic acids can partially inhibit our NanoGene assay. The mechanisms examined were (1) adsorption of humic acids on the particle surface; (2) particle aggregation induced by humic acids; (3) fluorescence quenching of quantum dots by humic acids during hybridization; (4) humic acids mimicking of target DNA; and (5) nonspecific binding between humic acids and target gDNA. The investigation showed that no adsorption of humic acids onto the particles' surface was observed for the humic acids' concentration. Particle aggregation and fluorescence quenching were also negligible. Humic acids also did not mimic the target gDNA except 1000 μg of humic acids per mL and hence should not contribute to the partial inhibition. Four of the above mechanisms were not related to the inhibition effect of humic acids particularly at the environmentally relevant concentrations (<100 μg/mL). However, a substantial amount of nonspecific binding was observed between the humic acids and target gDNA. This possibly results in lesser amount of target gDNA being captured by the probe and signaling DNA.

  8. Phenanthrene derivatives from roots and rhizomes of Asarum heterotropoides var. mandshuricum.

    PubMed

    Jing, Yu; Zhang, Yi-Fan; Shang, Ming-Ying; Yu, Jie; Tang, Jia-Wei; Liu, Guang-Xue; Li, Yao-Li; Li, Xiao-Mei; Wang, Xuan; Cai, Shao-Qing

    2017-03-01

    Five new phenanthrene derivatives: 9-ethoxy-7-methoxy-aristololactam IV (1), norcepharadione A N-β-d-glucopyranoside (2), aristololactamoside I (3), aristololactamoside II (4) and aristothiolactoside (5) together with eleven known phenanthrene derivatives (6-16) were isolated from the ethanol extract of the roots and rhizomes of Asarum heterotropoides var. mandshuricum. The aristololactams with substitution of ethoxy at C-9 position (1, 9, and 10) and the sulfur-containing phenanthrene derivative (5) were reported in the genus Asarum for the first time. Furthermore, six phenanthrene glucoside derivatives (2-5, 13 and 14) were also found in this genus for the first time and compounds 7 and 9-15 were isolated from the genus Asarum for the first time. Six of them (1, 2, 9, 10, 13 and 14) were submitted to cytotoxicity test against human renal proximal tubular epithelial cell lines (HK-2) using MTT and LDH assays. Compounds 1 and 10 showed significant cytotoxic activity against HK-2 cell lines with IC50 values of 18.18 and 20.44μmol/L in MTT assay and 84.36 and 35.06μmol/L in LDH assay, respectively. Compound 9 showed moderate cytotoxicity in MTT assay with IC50 values of 95.60μmol/L, but no cytotoxicity in LDH assay. Compounds 2, 13 and 14 showed cytotoxic effect in neither MTT assay nor LDH assay. Considering the other nephrotoxic phenanthrene derivatives (6, 8, 12, 15 and 16) previously tested, the results implied the potency of renal toxicity of this herb used as a medicine.

  9. Rapid impact of phenanthrene and arsenic on bacterial community structure and activities in sand batches.

    PubMed

    Cébron, A; Arsène-Ploetze, F; Bauda, P; Bertin, P N; Billard, P; Carapito, C; Devin, S; Goulhen-Chollet, F; Poirel, J; Leyval, C

    2014-01-01

    The impact of both organic and inorganic pollution on the structure of soil microbial communities is poorly documented. A short-time batch experiment (6 days) was conducted to study the impact of both types of pollutants on the taxonomic, metabolic and functional diversity of soil bacteria. For this purpose sand spiked with phenanthrene (500 mg kg(-1) sand) or arsenic (arsenite 0.66 mM and arsenate 12.5 mM) was supplemented with artificial root exudates and was inoculated with bacteria originated from an aged PAH and heavy-metal-polluted soil. The bacterial community was characterised using bacterial strain isolation, TTGE fingerprinting and proteomics. Without pollutant, or with phenanthrene or arsenic, there were no significant differences in the abundance of bacteria and the communities were dominated by Pseudomonas and Paenibacillus genera. However, at the concentrations used, both phenanthrene or arsenic were toxic as shown by the decrease in mineralisation activities. Using community-level physiological profiles (Biolog Ecoplates™) or differential proteomics, we observed that the pollutants had an impact on the community physiology, in particular phenanthrene induced a general cellular stress response with changes in the central metabolism and membrane protein synthesis. Real-time PCR quantification of functional genes and transcripts revealed that arsenic induced the transcription of functional arsenic resistance and speciation genes (arsB, ACR3 and aioA), while no transcription of PAH-degradation genes (PAH-dioxygenase and catechol-dioxygenase) was detected with phenanthrene. Altogether, in our tested conditions, pollutants do not have a major effect on community abundance or taxonomic composition but rather have an impact on metabolic and functional bacterial properties.

  10. The variability of standard artificial soils: cadmium and phenanthrene sorption measured by a batch equilibrium method.

    PubMed

    Bielská, Lucie; Hovorková, Ivana; Kuta, Jan; Machát, Jiří; Hofman, Jakub

    2017-01-01

    Artificial soil (AS) is used in soil ecotoxicology as a test medium or reference matrix. AS is prepared according to standard OECD/ISO protocols and components of local sources are usually used by laboratories. This may result in significant inter-laboratory variations in AS properties and, consequently, in the fate and bioavailability of tested chemicals. In order to reveal the extent and sources of variations, the batch equilibrium method was applied to measure the sorption of 2 model compounds (phenanthrene and cadmium) to 21 artificial soils from different laboratories. The distribution coefficients (Kd) of phenanthrene and cadmium varied over one order of magnitude: from 5.3 to 61.5L/kg for phenanthrene and from 17.9 to 190L/kg for cadmium. Variations in phenanthrene sorption could not be reliably explained by measured soil properties; not even by the total organic carbon (TOC) content which was expected. Cadmium logKd values significantly correlated with cation exchange capacity (CEC), pHH2O and pHKCl, with Pearson correlation coefficients of 0.62, 0.80, and 0.79, respectively. CEC and pHH2O together were able to explain 72% of cadmium logKd variability in the following model: logKd=0.29pHH2O+0.0032 CEC -0.53. Similarly, 66% of cadmium logKd variability could be explained by CEC and pHKCl in the model: logKd=0.27pHKCl+0.0028 CEC -0.23. Variable cadmium sorption in differing ASs could be partially treated with these models. However, considering the unpredictable variability of phenanthrene sorption, a more reliable solution for reducing the variability of ASs from different laboratories would be better harmonization of AS preparation and composition.

  11. The coupling of the plant and microbial catabolisms of phenanthrene in the rhizosphere of Medicago sativa.

    PubMed

    Muratova, Anna; Dubrovskaya, Ekaterina; Golubev, Sergey; Grinev, Vyacheslav; Chernyshova, Marina; Turkovskaya, Olga

    2015-09-01

    We studied the catabolism of the polycyclic aromatic hydrocarbon phenanthrene by four rhizobacterial strains and the possibility of enzymatic oxidation of this compound and its microbial metabolites by the root exudates of alfalfa (Medicago sativa L.) in order to detect the possible coupling of the plant and microbial metabolisms under the rhizospheric degradation of the organic pollutant. A comparative study of phenanthrene degradation pathways in the PAH-degrading rhizobacteria Ensifer meliloti, Pseudomonas kunmingensis, Rhizobium petrolearium, and Stenotrophomonas sp. allowed us to identify the key metabolites from the microbial transformation of phenanthrene, including 9,10-phenanthrenequinone, 2-carboxybenzaldehyde, and 1-hydroxy-2-naphthoic, salicylic, and o-phthalic acids. Sterile alfalfa plants were grown in the presence and absence of phenanthrene (0.03 g kg(-1)) in quartz sand under controlled environmental conditions to obtain plant root exudates. The root exudates were collected, concentrated by ultrafiltration, and the activity of oxidoreductases was detected spectrophotometrically by the oxidation rate for various substrates. The most marked activity was that of peroxidase, whereas the presence of oxidase and tyrosinase was detected on the verge of the assay sensitivity. Using alfalfa root exudates as a crude enzyme preparation, we found that in the presence of the synthetic mediator, the plant peroxidase could oxidize phenanthrene and its microbial metabolites. The results indicate the possibility of active participation of plants in the rhizospheric degradation of polycyclic aromatic hydrocarbons and their microbial metabolites, which makes it possible to speak about the coupling of the plant and microbial catabolisms of these contaminants in the rhizosphere.

  12. Mechanisms of humic substances degradation by fungi

    NASA Astrophysics Data System (ADS)

    Chen, Y.; Hadar, Y.; Grinhut, T.

    2012-04-01

    Humic substances (HS) are formed by secondary synthesis reactions (humification) during the decay process and transformation of biomolecules originating from plants and other dead organisms. In nature, HS are extremely resistant to biological degradation. Thus, these substances are major components in the C cycle and in the biosphere and therefore, the understanding of the process leading to their formation and transformation and degradation is vital. Fungi active in the decomposition process of HS include mainly ascomycetes and basidiomycetes that are common in the upper layer of forest and grassland soils. Many basidiomycetes belong to the white-rot fungi (WRF) and litter-decomposing fungi (LDF). These fungi are considered to be the most efficient lignin degraders due to their nonspecific oxidizing enzymes: manganese peroxidase (MnP), lignin peroxidase (LiP) and laccase. Although bacteria dominate compost and participate in the turnover of HS, their ability to degrade stable macromolecules such as lignin and HS is limited. The overall objectives of this research were to corroborate biodegradation processes of HS by WRF. The specific objectives were: (i) To isolate, identify and characterize HS degrading WRF from biosolids (BS) compost; (ii) To study the biodegradation process of three types of HS, which differ in their structure, by WRF isolated from BS compost; and (iii) To investigate the mechanisms of HA degradation by WRF using two main approaches: (a) Study the physical and chemical analyses of the organic compounds obtained from direct fungal degradation of HA as well as elucidation of the relevant enzymatic reactions; and (b) Study the enzymatic and biochemical mechanisms involved during HA degradation. In order to study the capability of fungi to degrade HS, seventy fungal strains were isolated from biosolids (BS) compost. Two of the most active fungal species were identified based on rDNA sequences and designated Trametes sp. M23 and Phanerochaetesp., Y6

  13. New insights into the dynamics of adsorption equilibria of humic matter as revealed by radiotracer studies

    NASA Astrophysics Data System (ADS)

    Lippold, Holger; Lippmann-Pipke, Johanna

    2014-05-01

    The mobility of contaminants in the subsurface hydrosphere can be governed by their interaction with aquatic humic substances, which may act as carriers. For modelling migration processes, retardation of humic molecules at mineral surfaces must be considered. There is, however, a lack of clarity concerning the reversibility of adsorption of these natural polyelectrolytes. In this work, evidence was provided that a dynamic adsorption equilibrium exists. For this purpose, adsorption of humic substances (purified Aldrich humic acid and an aquatic fulvic acid) onto kaolinite was examined in tracer exchange studies by means of 14C-labelled humic material. In addition, the kinetics of adsorption and desorption were investigated in batch experiments.

  14. The contribution of humic substances to the acidity of colored natural waters

    USGS Publications Warehouse

    Oliver, B.G.; Thurman, E.M.; Malcolm, R.L.

    1983-01-01

    An operationally defined carboxyl content of humic substances extracted from rivers, streams, lakes, wetlands, and groundwaters throughout the United States and Canada is reported. Despite the diversity of the samples, only small variations were observed in this humic carboxyl content. The dissociation behavior of two combined fulvic/humic acid extracts was studied and it was found that the dissociation of the humics varied in a predictable manner with pH. Using a carboxyl content of 10 ??eq/ mg humic organic carbon, and mass action quotient calculated from sample pH, the ionic balances of three highly colored Nova Scotia rivers were estimated. ?? 1983.

  15. The uniqueness of humic substances in each of soil, stream and marine environments

    USGS Publications Warehouse

    Malcolm, R.L.

    1990-01-01

    Definitive compositional differences are shown to exist for both fulvic acids and humic acids from soil, stream and marine environments by five different methods (1H and 13C NMR spectroscopy, 14C age and ?? 13C isotopic analyses, amino acid analyses and pyrolysis-mass spectrometry). Definitive differences are also found between fulvic acids and humic acids within each environment. These differences among humic substances from various sources are more readily discerned because the method employed for the isolation of humic substances from all environments excludes most of the non-humic components and results in more purified humic isolates from water and soils. The major compositional aspects of fulvic acids and humic acids which determine the observed characteristic differences in each environment are the amounts and compositions of saccharide, phenolic, methoxyl, aromatic, hydrocarbon, amino acid and nitrogen moieties.

  16. **1**5N-NMR INVESTIGATION OF HYDROXYLAMINE DERIVATIZED HUMIC SUBSTANCES.

    USGS Publications Warehouse

    Thorn, Kevin A.; Arterburn, Jeffrey B.; Mikita, Michael A.

    1986-01-01

    Humic substances are the most abundant naturally occurring refactory organic compounds in soils and water. They have a broad range of physical, chemical and physiological properties. In soils, humic substances contribute to the cation exchange capacity, help maintain the physical structure, and play a role in plant growth and nutrition. In aquatic systems, humic substances serve to regulate the levels of inorganic constituents, yield trihalomethanes upon chlorination, and transport or concentrate organic and inorganic pollutants. The oxygen containing functional groups of humic and fulvic acids are believed to play a key role in the chemical properties of humic substances. This study was undertaken to gain additional information on the specific types of oxygen functionalities in humic substances. Since the analysis of hydroxyl moieties had been earlier established, we focused our attention on the analysis of ketone and aldehyde functional groups in humic substances.

  17. Molecular weight, polydispersity, and spectroscopic properties of aquatic humic substances

    USGS Publications Warehouse

    Chin, Y.-P.; Aiken, G.; O'Loughlin, E.

    1994-01-01

    The number- and weight-averaged molecular weights of a number of aquatic fulvic acids, a commercial humic acid, and unfractionated organic matter from four natural water samples were measured by high-pressure size exclusion chromatography (HPSEC). Molecular weights determined in this manner compared favorably with those values reported in the literature. Both recent literature values and our data indicate that these substances are smaller and less polydisperse than previously believed. Moreover, the molecular weights of the organic matter from three of the four natural water samples compared favorably to the fulvic acid samples extracted from similar environments. Bulk spectroscopic properties of the fulvic substances such as molar absorptivity at 280 nm and the E4/E6 ratio were also measured. A strong correlation was observed between molar absorptivity, total aromaticity, and the weight average molecular weights of all the humic substances. This observation suggests that bulk spectroscopic properties can be used to quickly estimate the size of humic substances and their aromatic contents. Both parameters are important with respect to understanding humic substance mobility and their propensity to react with both organic and inorganic pollutants. ?? 1994 American Chemical Society.

  18. Humic first, A new theory on the origin of life

    NASA Astrophysics Data System (ADS)

    Daei, Mohammad Ali; Daei, Manijeh

    2016-04-01

    In 1953, Miller &Urey through a brilliant experiment demonstrated that the building blocks of life could evolve in primitive earth conditions1. In recent years scientists revealed that organic matters are not very rare compounds in comets, asteroids, and meteorites2. These facts show simple organic molecules on early earth could be quite enough to start development of life. But, how? Many theorists have tried to explain how life emerged from non life, but failed2. There is a huge gap between the simple building blocks, like amino acid, sugar, and lipid molecules, to a living cell with a very sophisticated structure and organization. Obviously, creation of a cell needed a qualified production line which had to be durable and active, can gather all biochemical ingredients, protect them from degradation, have catalyzing ability, provide numerous opportunities for interaction between basic molecules, and above all, have capability to react to different sources of energy. We are sure this perfect factory was available on primitive earth and is nothing except humic substance! At the moment, HS, are doing nearly all of these duties, among the others, under your feet in agricultural soils4. What are humic substances? According to IHSS definition "Humic substances (HS) are major components of the natural organic matter (NOM) in soil and water as well as in geological organic deposits such as lake sediments, peats, brown coals, and shales5." They come from polymerization of organic molecules, but looking at them like a simple aggregation of different organic molecules, is a huge mistake6! It seems they do not come together except for making a capable structure! HS are the first organic machinery which appeared in proplanetary disk, more than four billion years ago. Derived from simple inorganic molecules, humic substances construct a firm intermediate structure which connects none life to life. In other word, life road pass over the humic bridge. This does not mean that

  19. Destruction of humic substances by pulsed electrical discharge

    NASA Astrophysics Data System (ADS)

    Lobanova, G. L.; Yurmazova, T. A.; Shiyan, L. N.; Machekhina, K. I.; Davidenko, M. A.

    2017-01-01

    Currently, the water recourses in the territory of Tomsk region are groundwater which is limited to the high concentration of iron and manganese ions and organic substances. These impurities present in water in different forms such as soluble salts ant the colloid forms. Therefore, the present work is a part of a continuations researcher of the processes in natural waters containing humic substances at the influence of pulsed electrical discharges in a layer of iron pellets. It is shown that the main stage of water purification process of humic substances during treatment by pulsed electric discharge in the layer of iron granules is a difficult process including several stages such as formation of iron oxyhydroxide colloid particles, sorption and coagulation with humic macromolecules substances, growth of particle dispersed phase and precipitation. The reason for the formation and coagulation of the dispersed phase is a different state of charge of the colloid particles (zeta potentials of (Fe (OH)3) is +8 mV, zeta potentials of (Humic substances) is -70 mV. The most intense permanganate oxidation reduction to the maximum permissible concentration occurs at the processing time equal to 10 seconds. The contact time of active erosion products with sodium humate is established and it equals to 1 hour. The value of permanganate oxidation achieves maximum permissible concentration during this time and iron concentration in solution achieves maximum permissible concentration after filtration.

  20. CONDUCTOMETRIC CHARACTERIZATION OF DISSOLVED HUMIC MATERIALS. (R828158)

    EPA Science Inventory

    Conductometric replacement titrations of humic and fulvic acids dissolved in a slight excess of hydroxide were carried out with standard acid. The slope of the titration curve corresponding to the protonation of humate/fulvate was related to the electrophoretic mobility of the...

  1. Order of functionality loss during photodegradation of aquatic humic substances

    USGS Publications Warehouse

    Thorn, Kevin A.; Younger, Steven J.; Cox, Larry G.

    2009-01-01

    The time course photodegradation of the Nordic aquatic fulvic and humic acids and Suwannee River XAD-4 acids subjected to UV irradiation with an unfiltered medium pressure mercury lamp was studied by liquid-state 13C nuclear magnetic resonance. Photodecarboxylation was a significant pathway in all cases. Decreases in ketone, aromatic, and O-alkyl carbons were observed throughout the course of the irradiations, whereas C-alkyl carbons resisted photodegradation. Peaks attributable to the low-molecular-weight photodegradation products bicarbonate, formate, acetate, and succinate grew in intensity with irradiation time. The final products of the irradiations were decarboxylated, hydrophobic, predominantly C-alkyl and O-alkyl materials that were resistant to further photodegradation. The total amount of carbon susceptible to loss appeared to be related mainly to the total concentration of carbonyl and aromatic carbons and partly to the concentration of O-alkyl carbons in the fulvic, humic, and XAD-4 acids. The carbon losses for Nordic fulvic, Nordic Humic, Suwannee fulvic, and Suwannee XAD-4 acids were estimated to be 75, 63, 56, and 17%, respectively. More detailed analyses of the effects of irradiation on the carbonyl functionality in Nordic humic acid and Laurentian soil fulvic acid through reaction with hydroxylamine in conjunction with 15N nuclear magnetic resonance analysis confirmed preferential photodegradation of the quinone/hydroquinone functionality over ketone groups and the loss of ester groups in Laurentian fulvic acid.

  2. Sensitive life detection: extraction of nucleic acids sorbing to Mars analogue minerals

    NASA Astrophysics Data System (ADS)

    Direito, S. O. L.; Marees, A.; Röling, W. F. M.

    2011-10-01

    The main goal of space missions to Mars is to find irrefutable proof of life. Consequently, the development, evaluation and optimization of sensitive extraction and detection methods for biomarkers are of extreme importance. Our aim consisted in the optimization of sensitive extraction techniques for molecules storing hereditary information (nucleic acids such as DNA), since these are common in life forms. However, adsorption of nucleic acids to mineral matrixes and soils can generate low extraction yields. Therefore, a second aim was to determine adsorption and identify 'problematic' Mars analogue minerals. In addition, the development of a method for quantification of DNA recovery by the use of an internal control was proved to be essential, since sensitive extraction needs information on recovery.

  3. Can Humic Water Discharge Counteract Eutrophication in Coastal Waters?

    PubMed Central

    Andersson, Agneta; Jurgensone, Iveta; Rowe, Owen F.; Simonelli, Paolo; Bignert, Anders; Lundberg, Erik; Karlsson, Jan

    2013-01-01

    A common and established view is that increased inputs of nutrients to the sea, for example via river flooding, will cause eutrophication and phytoplankton blooms in coastal areas. We here show that this concept may be questioned in certain scenarios. Climate change has been predicted to cause increased inflow of freshwater to coastal areas in northern Europe. River waters in these areas are often brown from the presence of high concentrations of allochthonous dissolved organic carbon (humic carbon), in addition to nitrogen and phosphorus. In this study we investigated whether increased inputs of humic carbon can change the structure and production of the pelagic food web in the recipient seawater. In a mesocosm experiment unfiltered seawater from the northern Baltic Sea was fertilized with inorganic nutrients and humic carbon (CNP), and only with inorganic nutrients (NP). The system responded differently to the humic carbon addition. In NP treatments bacterial, phytoplankton and zooplankton production increased and the systems turned net autotrophic, whereas the CNP-treatment only bacterial and zooplankton production increased driving the system to net heterotrophy. The size-structure of the food web showed large variations in the different treatments. In the enriched NP treatments the phytoplankton community was dominated by filamentous >20 µm algae, while in the CNP treatments the phytoplankton was dominated by picocyanobacteria <5 µm. Our results suggest that climate change scenarios, resulting in increased humic-rich river inflow, may counteract eutrophication in coastal waters, leading to a promotion of the microbial food web and other heterotrophic organisms, driving the recipient coastal waters to net-heterotrophy. PMID:23637807

  4. Sorption characteristics of phenanthrene and pyrene to surfactant-modified peat from aqueous solution: the contribution of partition and adsorption.

    PubMed

    Zhou, Yanbo; Zhang, Ruzhuang; Gu, Xiaochen; Zhao, Qing; Lu, Jun

    2015-01-01

    In this paper, the sorption characteristics and mechanisms of phenanthrene and pyrene onto peat (PT) and surfactant-modified peat (MPT) were investigated. Sorption results fit closely to the Partition model and Freundlich model, the coefficient of determination (R²) were higher than 0.98 and 0.99, respectively. The contributions of partition and adsorption to the total sorption of phenanthrene and pyrene by PT and MPT were analyzed quantitatively. Results indicate that the sorption process is a combination of partition and adsorption, and partition plays a major role in the sorption process. The contribution of partition increased with the increasing of initial concentrations of polycyclic aromatic hydrocarbons. The sorption ability of phenanthrene and pyrene by PT and MPT followed the order of pyrene > phenanthrene. MPT has demonstrated potential as a promising new class of materials for environmental remediation of organic pollutants.

  5. Flocculant in wastewater affects dynamics of inorganic N and accelerates removal of phenanthrene and anthracene in soil.

    PubMed

    Fernandez-Luqueno, F; Thalasso, F; Luna-Guido, M L; Ceballos-Ramírez, J M; Ordoñez-Ruiz, I M; Dendooven, L

    2009-06-01

    Recycling of municipal wastewater requires treatment with flocculants, such as polyacrylamide. It is unknown how polyacrylamide in sludge affects removal of polycyclic aromatic hydrocarbons (PAH) from soil. An alkaline-saline soil and an agricultural soil were contaminated with phenanthrene and anthracene. Sludge with or without polyacrylamide was added while emission of CO(2) and concentrations of NH(4)(+), NO(3)(-), NO(2)(-), phenanthrene and anthracene were monitored in an aerobic incubation experiment. Polyacrylamide in the sludge had no effect on the production of CO(2), but it reduced the concentration of NH(4)(+), increased the concentration of NO(3)(-) in the Acolman soil and NO(2)(-) in the Texcoco soil, and increased N mineralization compared to the soil amended with sludge without polyacrylamide. After 112d, polyacrylamide accelerated the removal of anthracene from both soils and that of phenanthrene in the Acolman soil. It was found that polyacrylamide accelerated removal of phenanthrene and anthracene from soil.

  6. Reduction in the earthworm metabolomic response after phenanthrene exposure in soils with high soil organic carbon content.

    PubMed

    McKelvie, Jennifer R; Whitfield Åslund, Melissa; Celejewski, Magda A; Simpson, André J; Simpson, Myrna J

    2013-04-01

    We evaluated the correlation between soil organic carbon (OC) content and metabolic responses of Eisenia fetida earthworms after exposure to phenanthrene (58 ± 3 mg/kg) spiked into seven artificial soils with OC contents ranging from 1 to 27% OC. Principal component analysis of (1)H nuclear magnetic resonance (NMR) spectra of aqueous extracts identified statistically significant differences in the metabolic profiles of control and phenanthrene-exposed E. fetida in the 1% OC soil only. Partial least squares analysis identified a metabolic response in the four soils with OC values ≤11% which was well correlated to estimated phenanthrene porewater concentrations. The results suggest that the higher sorption capability of high OC soils decreased the bioavailability of phenanthrene and the subsequent metabolic response of E. fetida.

  7. Effects of humic substances on the bioconcentration of polycyclic aromatic hydrocarbons: Correlations with spectroscopic and chemical properties of humic substances

    USGS Publications Warehouse

    Haitzer, M.; Abbt-Braun, G.; Traunspurger, W.; Steinberg, C.E.W.

    1999-01-01

    The presence of dissolved humic substances (HS, fulvic and humic acids) generally reduces the uptake of hydrophobic organic compounds into aquatic organisms. The extent of this effect depends both on the concentration and on the origin of the HS. The aim of this study was to investigate the role of qualitative differences between HS from different origins. The effects of seven different HS on the bioconcentration of pyrene and benzo[a]pyrene (BaP) in the nematode Caenorhabditis elegans were related to the spectroscopic and chemical properties of the HS. The effect of each humic material on the bioconcentration of pyrene or BaP was quantified as a 'biologically determined' partition coefficient K(DOC). We observed significant linear relationships between K(DOC) and the atomic H/C ratio, the specific absorptivity at 254 nm, the content of aromatic carbons (as determined by 13C nuclear magnetic resonance spectroscopy, the copper-complexing capacity, the content of phenolic OH groups, and the molecular weight of the HS. There was no discernible relationship of K(DOC) with the atomic (N + O)/C ratio, an indicator of the polarity of HS. Taken together, our results show that the variability in the effects of HS from different origins could be related to variations in bulk properties of the HS. Parameters describing the aromaticity of the humic materials seemed to be most useful for estimating effects of HS on the bioconcentration of pyrene and BaP.

  8. Effects of humic substances on the bioconcentration of polycyclic aromatic hydrocarbons: Correlations with spectroscopic and chemical properties of humic substances

    SciTech Connect

    Haitzer, M.; Abbt-Braun, G.; Traunspurger, W.; Steinberg, C.E.W.

    1999-12-01

    The presence of dissolved humic substances (HS, fulvic and humic acids) generally reduces the uptake of hydrophobic organic compounds into aquatic organisms. The extent of this effect depends both on the concentration and on the origin of the HS. The aim of this study was to investigate the role of qualitative differences between HS from different origins. The effects of seven different HS on the bioconcentration of pyrene and benzo[a]pyrene (BaP) in the nematode Caenorhabditis elegans were related to the spectroscopic and chemical properties of the HS. The effect of each humic material on the bioconcentration of pyrene or BaP was quantified as a biologically determined partition coefficient K{sub DOC}. The authors observed significant linear relationships between K{sub DOC} and the atomic H/C ratio, the specific absorptivity at 254 nm, the content of aromatic carbons as determined by {sup 13}C nuclear magnetic resonance spectroscopy, the copper-complexing capacity, the content of phenolic OH groups, and the molecular weight of the HS. There was no discernible relationship of K{sub DOC} with the atomic (N + O)/C ratio, an indicator of the polarity of HS. Taken together, their results show that the variability in the effects of HS from different origins could be related to variations in bulk properties of the HS. Parameters describing the aromaticity of the humic materials seemed to be most useful for estimating effects of HS on the bioconcentration of pyrene and BaP.

  9. Effect of bioaugmentation to enhance phytoremediation for removal of phenanthrene and pyrene from soil with Sorghum and Onobrychis sativa

    PubMed Central

    2014-01-01

    The use of plants to remove Poly-aromatic-hydrocarbons (PAHs) from soil (phytoremediation) is emerging as a cost-effective method. Phytoremediation of contaminated soils can be promoted by the use of adding microorganisms with the potential of pollution biodegradation (bioaugmentation). In the present work, the effect of bacterial consortium was studied on the capability of Sorghum and Onobrychis sativa for the phytoremediation of soils contaminated with phenanthrene and pyrene. 1.5 kg of the contaminated soil in the ratio of 100 and 300 mg phenanthrene and/or pyrene per kg of dry soil was then transferred into each pot (nine modes). The removal efficiency of natural, phytoremediation and bioaugmentation, separately and combined, were evaluated. The samples were kept under field conditions, and the remaining concentrations of pyrene and phenanthrene were determined after 120 days. The rhizosphere as well as the microbial population of the soil was also determined. Results indicated that both plants were able to significantly remove pyrene and phenanthrene from the contaminated soil samples. Phytoremediation alone had the removal efficiency of about 63% and 74.5% for pyrene and phenanthrene respectively. In the combined mode, the removal efficiency dramatically increased, leading to pyrene and phenanthrene removal efficiencies of 74.1% and 85.02% for Onobrychis sativa and 73.84% and 85.2% for sorghum, respectively. According to the results from the present work, it can be concluded that Onobrychis sativa and sorghum are both efficient in removing pyrene and phenanthrene from contamination and bioaugmentation can significantly enhance the phytoremediation of soils contaminated with pyrene and phenanthrene by 22% and 16% respectively. PMID:24406158

  10. Effect of bioaugmentation to enhance phytoremediation for removal of phenanthrene and pyrene from soil with Sorghum and Onobrychis sativa.

    PubMed

    Baneshi, Mohammad Mehdi; Rezaei Kalantary, Roshanak; Jonidi Jafari, Ahmad; Nasseri, Simin; Jaafarzadeh, Nemat; Esrafili, Ali

    2014-01-09

    The use of plants to remove Poly-aromatic-hydrocarbons (PAHs) from soil (phytoremediation) is emerging as a cost-effective method. Phytoremediation of contaminated soils can be promoted by the use of adding microorganisms with the potential of pollution biodegradation (bioaugmentation). In the present work, the effect of bacterial consortium was studied on the capability of Sorghum and Onobrychis sativa for the phytoremediation of soils contaminated with phenanthrene and pyrene. 1.5 kg of the contaminated soil in the ratio of 100 and 300 mg phenanthrene and/or pyrene per kg of dry soil was then transferred into each pot (nine modes). The removal efficiency of natural, phytoremediation and bioaugmentation, separately and combined, were evaluated. The samples were kept under field conditions, and the remaining concentrations of pyrene and phenanthrene were determined after 120 days. The rhizosphere as well as the microbial population of the soil was also determined. Results indicated that both plants were able to significantly remove pyrene and phenanthrene from the contaminated soil samples. Phytoremediation alone had the removal efficiency of about 63% and 74.5% for pyrene and phenanthrene respectively. In the combined mode, the removal efficiency dramatically increased, leading to pyrene and phenanthrene removal efficiencies of 74.1% and 85.02% for Onobrychis sativa and 73.84% and 85.2% for sorghum, respectively. According to the results from the present work, it can be concluded that Onobrychis sativa and sorghum are both efficient in removing pyrene and phenanthrene from contamination and bioaugmentation can significantly enhance the phytoremediation of soils contaminated with pyrene and phenanthrene by 22% and 16% respectively.

  11. In situ fluorescence measurements of protein-, humic- and HAP-like materials in the Northwestern Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Tedetti, Marc; Bachet, Caroline; Germain, Chloé; Ferretto, Nicolas; Bhairy, Nagib; Guigue, Catherine; Besson, Florent; Beguery, Laurent; Goutx, Madeleine

    2015-04-01

    Understanding the biogeochemical functioning of the ocean requires high frequency measurements of dissolved organic matter (DOM) descriptors. For 10 years, the technological developments of fluorescence sensors try to cover this need. In this context, our laboratory developed the MiniFluo-UV sensor, a prototype of miniaturized submersible fluorometer for the detection of aromatic compounds that fluoresce in the UV spectral domain. The qualification of the sensor consisted in measurements of drift, linearity, repeatability, sensitivity to light, temperature and pressure, and detection limits of phenanthrene (HAP) and tryptophan (aromatic amino acid) in standard solutions. Measurements were also conducted in crude oil water soluble fractions (WSFs). The MiniFluo-UV sensor was then deployed in two distinct areas of the Northwestern Mediterranean Sea: 1) in the Gulf of Lion during the continuous monitoring of the surface water layer (DEWEX cruise, winter and spring 2013) and 2) in the Bay of Marseilles, heavily impacted by urban activities, where the sensor was mounted onto the SeaExplorer underwater glider and onto a CTD vertical profiler (July-December 2014). These platforms were also equipped with a humic-like fluorescence sensor and other sensors for hydrological and biogeochemical parameters (T, S, Chla, oxygen, turbidity). The patterns of fluorescence signatures enabled to distinguish interesting distributions of DOM in relation with hydrological features and spring biological production in the Gulf of Lion, and showed the accumulation of contaminants in marine areas under anthropogenic pressure. This work was conducted within the framework of the ANR-09-ECOT-009-01 "IBISCUS" in collaboration with ALSEAMAR-ALCEN (Aix-en-Provence) and MicroModule (Brest) companies. It is relevant to WP5 NEXOS objectives. The SACEUP team of the DEWEX-MERMEX experiment is warmly acknowledged.

  12. Effects of oil dispersant and oil on sorption and desorption of phenanthrene with Gulf Coast marine sediments.

    PubMed

    Gong, Yanyan; Zhao, Xiao; O'Reilly, S E; Qian, Tianwei; Zhao, Dongye

    2014-02-01

    Effects of a model oil dispersant (Corexit EC9500A) on sorption/desorption of phenanthrene were investigated with two marine sediments. Kinetic data revealed that the presence of the dispersant at 18 mg/L enhanced phenanthrene uptake by up to 7%, whereas the same dispersant during desorption reduced phenanthrene desorption by up to 5%. Sorption isotherms confirmed that at dispersant concentrations of 18 and 180 mg/L, phenanthrene uptake progressively increased for both sediments. Furthermore, the presence of the dispersant during desorption induced remarkable sorption hysteresis. The effects were attributed to added phenanthrene affinity and capacity due to sorption of the dispersant on the sediments. Dual-mode models adequately simulated sorption isotherms and kinetic data in the presence of the dispersant. Water accommodated oil (WAO) and dispersant-enhanced WAO increased phenanthrene sorption by up to 22%. This information is important for understanding roles of oil dispersants on the distribution and transport of petroleum PAHs in seawater-sediments.

  13. Biodegradation of phenanthrene in bioaugmented microcosm by consortium ASP developed from coastal sediment of Alang-Sosiya ship breaking yard.

    PubMed

    Patel, Vilas; Patel, Janki; Madamwar, Datta

    2013-09-15

    A phenanthrene-degrading bacterial consortium (ASP) was developed using sediment from the Alang-Sosiya shipbreaking yard at Gujarat, India. 16S rRNA gene-based molecular analyses revealed that the bacterial consortium consisted of six bacterial strains: Bacillus sp. ASP1, Pseudomonas sp. ASP2, Stenotrophomonas maltophilia strain ASP3, Staphylococcus sp. ASP4, Geobacillus sp. ASP5 and Alcaligenes sp. ASP6. The consortium was able to degrade 300 ppm of phenanthrene and 1000 ppm of naphthalene within 120 h and 48 h, respectively. Tween 80 showed a positive effect on phenanthrene degradation. The consortium was able to consume maximum phenanthrene at the rate of 46 mg/h/l and degrade phenanthrene in the presence of other petroleum hydrocarbons. A microcosm study was conducted to test the consortium's bioremediation potential. Phenanthrene degradation increased from 61% to 94% in sediment bioaugmented with the consortium. Simultaneously, bacterial counts and dehydrogenase activities also increased in the bioaugmented sediment. These results suggest that microbial consortium bioaugmentation may be a promising technology for bioremediation.

  14. Effects of humic acid-metal complexes on hepatic carnitine palmitoyltransferase, carnitine acetyltransferase and catalase activities

    SciTech Connect

    Fungjou Lu; Youngshin Chen . Dept. of Biochemistry); Tienshang Huang . Dept. of Medicine)

    1994-03-01

    A significant increase in activities of hepatic carnitine palmitoyltransferase and carnitine acetyltransferase was observed in male Balb/c mice intraperitoneally injected for 40 d with 0.125 mg/0.1 ml/d humic acid-metal complexes. Among these complexes, the humic acid-As complex was relatively effective, whereas humic acid-25 metal complex was more effective, and humic acid-26 metal complex was most effective. However, humic acid or metal mixtures, or metal such as As alone, was not effective. Humic acid-metal complexes also significantly decreased hepatic catalase activity. A marked decrease of 60-kDa polypeptide in liver cytoplasm was also observed on SDS-polyacrylamide gel electrophoresis after the mice had been injected with the complexes. Morphological analysis of a histopathological biopsy of such treated mice revealed several changes in hepatocytes, including focal necrosis and cell infiltration, mild fatty changes, reactive nuclei, and hypertrophy. Humic acid-metal complexes affect activities of metabolic enzymes of fatty acids, and this results in accumulation of hydrogen peroxide and increase of the lipid peroxidation. The products of lipid peroxidation may be responsible for liver damage and possible carcinogenesis. Previous studies in this laboratory had shown that humic acid-metal complex altered the coagulation system and that humic acid, per se, caused vasculopathy. Therefore, humic acid-metal complexes may be main causal factors of not only so-called blackfoot disease, but also the liver cancer prevailing on the southwestern coast of Taiwan.

  15. Digestive determinants of benzo[a]pyrene and phenanthrene bioaccumulation by a deposit-feeding polychaete

    SciTech Connect

    Penry, D.L.; Weston, D.P.

    1998-11-01

    The uptake of hydrophobic contaminants from ingested sediment can contribute significantly to body burdens of deposit feeders, and feeding behavior and digestive physiology can play important roles in bioaccumulation. The authors examined the uptake of polycyclic aromatic hydrocarbons (PAHs) by the deposit-feeding polychaete Abarenicola pacifica in experiments in which worms were first acclimated to low or high organic carbon sediments with 0.08 or 0.45% total organic carbon, respectively and then transferred to low or high organic carbon test sediments contaminated with radiolabeled phenanthrene or benzo[a]pyrene. Ingestion rate was measurements are essential in many types of bioaccumulation studies because differences in ingestion rates between sediment types may confound some traditional measures of bioavailability. Physiological acclimation to the low or high organic carbon sediments did not appear to affect PAH uptake from the test sediments, but acclimation did affect biotransformation capabilities, particularly for phenanthrene.

  16. Impact of activated carbon, biochar and compost on the desorption and mineralization of phenanthrene in soil.

    PubMed

    Marchal, Geoffrey; Smith, Kilian E C; Rein, Arno; Winding, Anne; Wollensen de Jonge, Lis; Trapp, Stefan; Karlson, Ulrich G

    2013-10-01

    Sorption of PAHs to carbonaceous soil amendments reduces their dissolved concentrations, limiting toxicity but also potentially biodegradation. Therefore, the maximum abiotic desorption of freshly sorbed phenanthrene (≤5 mg kg(-1)) was measured in three soils amended with activated carbon (AC), biochar or compost. Total amounts of phenanthrene desorbed were similar between the different soils, but the amendment type had a large influence. Complete desorption was observed in the unamended and compost amended soils, but this reduced for biochar (41% desorbed) and AC (8% desorbed). Cumulative amounts mineralized were 28% for the unamended control, 19% for compost, 13% for biochar and 4% for AC. Therefore, the effects of the amendments in soil in reducing desorption were also reflected in the extents of mineralization. Modeling was used to analyze key processes, indicating that for the AC and charcoal treatments bacterial activity did not limit mineralization, but rather desorption into the dissolved phase.

  17. The growth of phenanthrene from naphthalene by C2H2 additions

    NASA Astrophysics Data System (ADS)

    Bauschlicher, Charles W., Jr.

    2015-07-01

    Two paths are investigated for the growth of phenanthrene from naphthalene by the addition of C2H2 groups. The first series of steps leads to acenaphthylene (ACN), which is consistent with the path found previously. The addition of C2H2 to ACN can yield a product with two adjacent five-membered rings. Opening one five-membered ring produces a five-membered ring with CH2 side group. This can be converted to a six-membered ring in a manner analogous to the hydrogen atom catalysed fulvene to benzene conversion. A second path, with a somewhat higher barrier, can also lead to the phenanthrene product. The transition state for the second path is essentially isoenergetic with the stating material of ACN + C2H2 + H.

  18. {Quantification of Colloidal Blocking by Humic Acids in Porous Media

    NASA Astrophysics Data System (ADS)

    Yang, X.; Flynn, R.; von der Kammer, F.; Hofmann, T.

    2009-04-01

    Humic acids (humics), resulting from the partial decomposition of organic matter, occur widely in nature and form a major constituent of environmental natural organic matter (NOM). Although their ability to promote the dissolution of many substances has been widely recognized, quantification of the influence of humics on the fate and transport of particulate matter has proven less conclusive. One dimensional dynamic column tests involving the injection of suspensions of fluorescence stained 200nm latex microspheres (microspheres) and Suwannee River Humic Acid (SRHA) through columns filled with partly iron-coated quartz sand permitted the influence of humics on colloid deposition in water saturated porous media under controlled conditions to be studied. Tests consisted of two series of experiments. The first involved the injection of an initial pulse of 13 pore volumes (PV) of 10.4ppm microspheres that resulted in a gradual rise in the colloid's concentration in the column effluent to 8.4% of that injected. Injection of further two identical pulses of 13 PV of colloid, separated by pulses of about 10 PV of colloid-free flushing water resulted in a sustained rise in effluent concentration in the breakthrough of successive pulses. Colloid response, modeled using a random sequential adsorption (RSA) model, suggested that the system required the deposition 1.35x1010 colloids on the sand surface for each 1% rise in relative concentration observed in column effluent. The second series of experiments involved the injection of an initial pulse of 13 pore volumes of colloid suspension followed by the injection of four pore volumes of 5 mg/l SRHA. A mass balance of column effluent suggested that the column retained 98.8% of SRHA injected. Subsequent injection of a second pulse of 13 PV of microspheres saw colloidal concentration breakthrough in column effluent jump to 16% after which it continued to rise at a rate comparable to that in SRHA-free experiments. RSA modeling of

  19. Degradation of phenanthrene, fluorene, fluoranthene, and pyrene by a Mycobacterium sp

    SciTech Connect

    Boldrin, B.; Tiehm, A.; Fritzsche, C. )

    1993-06-01

    Contamination of the environment with polycyclic aromatic hydrocarbons are considered hazardous so remediation of contaminated sites is of interest. This paper describes the isolation and characterization of a scotochromogenic Mycobacterium sp. that metabolizes pyrene, flouranthene, phenanthrene, and several other aromatic compounds as sole carbon sources. Exponential, non-substrate-limited degradation and growth as characteristic parameters of the bacterium are investigated. 26 refs., 1 fig., 2 tabs.

  20. Mechanistic characterization of adsorption and slow desorption of phenanthrene aged in soils

    SciTech Connect

    Abdul Abu; Steve Smith

    2006-09-01

    Long-term adsorption of phenanthrene to soils was characterized in a silt-loam (LHS), a sandy soil (SBS) from an uncontaminated area of a former coal treatment facility in the north of England and a podzolized soil (CNS) by use of the Polanyi-Manes model, a Langmuir-type model, and a black carbon-water distribution coefficient (K{sub BC}) at a relative aqueous concentration (C{sub e}/S{sub w}) of 0.002 - 0.32. Aqueous desorption kinetic tests and temperature-programmed desorption (TPD) were also used to evaluate phenanthrene diffusivities and desorption activation energies. Adsorption contribution in soils was 48-70% after 30 days and 64-95% after 270 days. Significant increases in adsorption capacity with aging suggest that accessibility of phenanthrene to fractions of SBS soil matrix was controlled by sorptive diffusion at narrow meso- and micropore constrictions. Similar trends were not significant for LHS silt-loam or CNS podzol. Analysis of TPD profiles reveal desorption activation energies of 35-53 kJ/mol and diffusivities of 1.6 x 10{sup -7-}9.7 10{sup -8} cm{sup 2}/s. TPD tests also indicate that the fraction of phenanthrene mass not diffusing from soils was located within micropores and narrow width mesopores with a corresponding volume of 1.83 10{sup -5-}6.3710{sup -5} cm{sup 3}/g. These values were consistent with the modeled adsorption contributions, thus demonstrating the need for such complimentary analytical approach in the risk assessment of organic contaminants. 41 refs., 2 figs., 4 tabs.

  1. A novel solubilization of phenanthrene using Winsor I microemulsion-based sodium castor oil sulfate.

    PubMed

    Zhao, Baowei; Zhu, Lizhong; Gao, Yanzheng

    2005-03-17

    Problems associated with polycyclic aromatic hydrocarbons (PAHs) contaminated site in environmental media have received increasing attention. Ex situ soil washing is commonly used for treating contaminated soils by separating the most contaminated fraction of the soil for disposal. Surfactant-enhanced soil washing is being considered with increasing frequency to actually achieve soil-contaminant separation. In this research, a novel solubilization of phenanthrene and extraction of phenanthrene from spiked soil by sodium castor oil sulfate (SCOS) microemulsion was presented and compared with the conventional surfactants, Triton X-100 (TX100), Tween 80 (TW80), Brij35, sodium dodecylbenzene sulfonate (SDBS) and sodium dodecyl sulfate (SDS). Unlike conventional surfactants, SCOS forms stable microemulsion in water and thus behaves much like a separate bulk phase in concentrating organic solutes. The extent of solubility enhancement is linearly proportional to the concentration of SCOS microemulsion, in contrast with the effect of a conventional surfactant in which a sharp inflection occurs in the vicinity of the measured critical micelle concentration. SCOS microemulsion exhibits the largest mass solubilization ratio among the selected surface active agents (SAAs) in both soil-free system and soil-water system. The partitioning coefficients of phenanthrene between the emulsified phase and the aqueous phase, Kem, is slightly larger than those between the micellar pseudo phase and the aqueous phase, Kmc. The extraction experiments demonstrate high and fast desorption of phenanthrene from spiked soil by SCOS microemulsion perhaps due to its high solubilization capacity compared with the conventional surfactant solutions. The results show that SCOS could be an attractive alternative to synthetic surfactants in ex situ washing for PAH-contaminated soils.

  2. Transcriptomics reveals extensive inducible biotransformation in the soil-dwelling invertebrate Folsomia candida exposed to phenanthrene

    PubMed Central

    Nota, Benjamin; Bosse, Mirte; Ylstra, Bauke; van Straalen, Nico M; Roelofs, Dick

    2009-01-01

    Background Polycyclic aromatic hydrocarbons are common pollutants in soil, have negative effects on soil ecosystems, and are potentially carcinogenic. The Springtail (Collembola) Folsomia candida is often used as an indicator species for soil toxicity. Here we report a toxicogenomic study that translates the ecological effects of the polycyclic aromatic hydrocarbon phenanthrene in soil to the early transcriptomic responses in Folsomia candida. Results Microarrays were used to examine two different exposure concentrations of phenanthrene, namely the EC10 (24.95 mg kg-1 soil) and EC50 (45.80 mg kg-1 soil) on reproduction of this springtail, which evoked 405 and 251 differentially expressed transcripts, respectively. Fifty transcripts were differential in response to either concentration. Many transcripts encoding xenobiotic detoxification and biotransformation enzymes (phases I, II, and III) were upregulated in response to either concentration. Furthermore, indications of general and oxidative stress were found in response to phenanthrene. Chitin metabolism appeared to be disrupted particularly at the low concentration, and protein translation appeared suppressed at the high concentration of phenanthrene; most likely in order to reallocate energy budgets for the detoxification process. Finally, an immune response was evoked especially in response to the high effect concentration, which was also described in a previous transcriptomic study using the same effect concentration (EC50) of cadmium. Conclusion Our study provides new insights in the molecular mode of action of the important polluting class of polycyclic aromatic hydrocarbons in soil animals. Furthermore, we present a fast, sensitive, and specific soil toxicity test which enhances traditional tests and may help to improve current environmental risk assessments and monitoring of potentially polluted sites. PMID:19457238

  3. [Structural changes of aged biochar and the influence on phenanthrene adsorption].

    PubMed

    Tang, Wei; Guo, Yue; Wu, Jing-Gui; Huang, Zhao-Qin; Dai, Jing-Yu

    2014-07-01

    Biochars prepared by pyrolysis of rice husk at 350 degrees C and 550 degrees C were incubated in the lucifugal thermostat for 300 d. Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS), Scanning Electron Microscopy (SEM), and Nuclear Magnetic Resonance (NMR) techniques were applied to explore the structural change before and after incubation. It was found that the oxygen content was increased after incubation, suggesting the formation of oxygen-containing functional groups. Incubation of the biochars also enhanced their nonlinear adsorption of phenanthrene. Structural change subjected to incubation was in fact affected by the pyrolysis temperatures at which the biochars were synthesized. Increase of polarity and decrease of aromaticity were found for biochars prepared at 350 degrees C. In contrast, incubation of biochars prepared at 550 degrees C resulted in increased aliphatic contents and aromaticity, as well as decrease of carboxyl group. The adsorption capacity of phenanthrene predicted by Langmuir model was 3.57 and 2.35 mg x g(-1) for new and aged biochar with lower pyrolysis temperature, respectively. It was assumed that change of the surface structure of the biochars due to aging inhibited the adsorption. On the contrary, aging of biochares prepared at 550 degrees C resulted in enhanced adsorption capacity of phenanthrene from 0.42 to 4.17 mg x (-1), which was probably correlated to the partition effect due to enhanced aromaticity. The data obtained in this research suggested that aging of biochars potentially affected the fate of the pollutants in environment.

  4. Effects of oil dispersant on ozone oxidation of phenanthrene and pyrene in marine water.

    PubMed

    Gong, Yanyan; Zhao, Dongye

    2017-04-01

    This work investigated effects of a popular oil dispersant (Corexit EC9500A) on oxidation of phenanthrene and pyrene (two model polycyclic aromatic hydrocarbons) in Gulf coast seawater under simulated atmospheric ozone. The degradation data followed a two-stage pseudo-first order kinetics, a slower initial reaction rate followed by a much faster rate in longer time. The ozonation rate for pyrene was faster than that for phenanthrene. The presence of 18 and 180 mg/L of the dispersant inhibited the first-order degradation rate by 32-80% for phenanthrene, and 51-85% for pyrene. In the presence of 18 mg/L of the dispersant, the pyrene degradation rate increased with increasing ozone concentration, but decreased with increasing solution pH and temperature, while remained independent of ionic strength. For the first time, the results indicate that atmospheric ozone may play a significant role in the weathering of dispersed persistent oil components in natural and engineered systems.

  5. Phenanthrene and pyrene sorption and intraparticle diffusion in polyoxymethylene, coke, and activated carbon

    SciTech Connect

    Sungwoo Ahn; David Werner; Hrissi K. Karapanagioti; Donald R. McGlothlin; Richard N. Zare; Richard G. Luthy

    2005-09-01

    The authors report sorption isotherms and uptake kinetics for phenanthrene and pyrene with three organic model sorbents: polyoxymethylene (POM), coke breeze, and activated carbon. Batch equilibration and kinetic experiments were combined with the direct observation of the long-term diffusion of phenanthrene and pyrene as measured within cross-sectioned particles using microprobe laser-desorption laser-ionization mass spectroscopy ({mu}L{sup 2}MS). For POM pellets, the intraparticle concentration profiles predicted from kinetic batch experiments and a polymer diffusion model with spherical geometry are in agreement with the independent {mu}L{sup 2}MS measurements. For coke particles, the apparent diffusivities decreased with smaller particle size. These trends in diffusivities were described by a sorption-retarded pore diffusion model with a particle-size-dependent solid-water partitioning coefficient obtained from apparent equilibrium observed in the kinetic batch studies. For activated carbon, the {mu}L{sup 2}MS measurements showed faster radial diffusion of phenanthrene and pyrene into the particle interior than predicted from diffusion models based on a single sorption domain and diffusivity. A branched pore kinetic model, comprising polycyclic aromatic hydrocarbon (PAH) macropore diffusion with kinetic exchange of PAH between macroporous and microporous domains, fits the experimental observations better. It is not possible to make independent parameter estimations for intraparticle diffusion in activated carbon using present procedures. 41 refs., 4 figs., 3 tabs.

  6. Detoxification of fluorene, phenanthrene, carbazole, and p-cresol as studied by the Microtox

    SciTech Connect

    Renoux, A.Y.; Millette, D.; Samson, R.

    1995-12-31

    A column experiment was conducted in order to study the evolution of the toxicity of creosote-related compound mixtures during aerobic biodegradation in a saturated hydrodynamic groundwater environment. The Microtox assay was used to characterize the toxicity of phenanthrene, fluorene, carbazole and p-cresol, separately and in mixtures, and to evaluate their detoxification during biodegradation. Phenanthrene, fluorene and p-cresol, separately solubilized in an aqueous phase, produced toxic effects on P. phosphoreum luminescence emission; 15 min-IC50 values of 140 {micro}g/L, 600 {micro}g/L and 1,500 {micro}g/L respectively were determined. Carbazole appeared as poorly toxic. The detoxification of the mixture solutions was demonstrated after having passed through the columns. Phenanthrene, fluorene and carbazole combined at different proportion produced between 24.4% and 49.3% of inhibition, whereas at the last port of the columns the inhibition values of the outflows averaged 6%. The presence of 10,000 {micro}g/L of p-cresol enhanced this efficiency of detoxification, since the inhibition of the mixture with the other compounds, which was 81.4% before injection, decreased to 15.8% after having passed through the first 5 cm of the column, and was not detectable at its last two pores. The acute toxicity test corroborated the chemical analysis, reflecting the compound elimination.

  7. Desorptive behavior of pentachlorophenol (PCP) and phenanthrene in soil-water systems

    SciTech Connect

    Fall, C.; Chaouki, J.; Chavarie, C.

    2000-04-01

    Recent investigations have prompted the need for a better understanding of the complete desorptive behavior of hydrophobic organic compounds in soils. The present study evaluated the irreversibilities associated with the desorption of pentachlorophenol (PCP) and phenanthrene from different types of soils. The study also examined the influence of solid-liquid ratio of the current batch desorption tests, specifically the completeness and accuracy of data gathered for establishing isotherms. Results demonstrated that the desorption of PCP and phenanthrene from contaminated soils can lead to three different types of behavior: complete reversibility, partial reversibility, or total irreversibility. The equilibrium adsorption constant (K{sub d}) is identified as a key parameter that indirectly sets the extent of hysteresis during the reverse process of desorption. According to the data, irreversibility occurs more in soils with a large adsorption capacity, that is, when K{sub d} is approximately 50 mL/g or more in the case of the phenanthrene- and PCP-soil systems evaluated. Furthermore, to facilitate the desorption experiments overall, the study proposes selection criteria for the solid-liquid ratio of batch tests to allow for variations in the adsorption capacity of each soil.

  8. Factors affecting the biodegradation of phenanthrene initially dissolved in different nonaqueous-phase liquids

    SciTech Connect

    Carroquino, M.J.; Alexander, M.

    1998-02-01

    A study was conducted of the importance of measured partitioning rate, the nonaqueous-phase liquid (NAPL)-water interfacial area, and the toxicity of NAPLs to the biodegradation of constituents of NAPLs. Bacterial mineralization of phenanthrene was slower if the compound was initially dissolved in phthalate esters than in aliphatic hydrocarbons with several NAPL-water interfacial areas. The differences were not the result of toxicity of the test NAPLs. The rates of partitioning of phenanthrene from NAPLs to water were faster with larger interfacial areas, but a consistent influence of interfacial area on the rate of mineralization was not evident. The measured rates of partitioning from NAPLs to water under sterile conditions varied among the NAPLs, the mass transfer rates being slower with phthalate esters than with alkanes. The rates of mineralization of phenanthrene initially in NAPLs were correlated with measured partitioning rates, but the rates of biodegradation were sometimes faster than the partitioning rates measured under sterile conditions. Although the rates of biodegradation of a constituent of nontoxic NAPLs are generally related to rates of mass transfer determined under sterile conditions, the authors suggest that the partitioning rate determined in the absence of microorganisms is not an adequate predictor of the maximum rate of biodegradation of such constituents.

  9. Biomarkers indicate mixture toxicities of fluorene and phenanthrene with endosulfan toward earthworm (Eisenia fetida).

    PubMed

    Nam, Tae-Hoon; Kim, Leesun; Jeon, Hwang-Ju; Kim, Kyeongnam; Ok, Yong-Sik; Choi, Sung-Deuk; Lee, Sung-Eun

    2017-04-01

    α-Endosulfan and some polycyclic aromatic compounds (PAHs) are persistent in the environment and can reach crop products via contaminated agricultural soils. They may even be present as mixtures in the soil and induce mixture toxicity in soil organisms such as earthworms. In this study, the combined toxicities of PAHs with α-endosulfan were determined in Eisenia fetida adults using an artificial soil system. α-Endosulfan and five PAHs were tested for their acute toxicity toward E. fetida in artificial soils. Only α-endosulfan, fluorene, and phenanthrene showed acute toxicities, with LC50 values of 9.7, 133.2, and 86.2 mg kg(-1), respectively. A mixture toxicity assay was conducted using α-endosulfan at LC10 and fluorene or phenanthrene at LC50 in the artificial soils. Upon exposure to the mixture of fluorene and α-endosulfan, earthworms were killed in increasing numbers owing to their synergistic effects, while no other mixture showed any additional toxicity toward the earthworms. Along with the acute toxicity results, the biochemical and molecular changes in the fluorene- and phenanthrene-treated earthworms with or without α-endosulfan treatment demonstrated that enhancement of glutathione S-transferase activity was dependent on the addition of PAH chemicals, and the HSP70 gene expression increased with the addition of α-endosulfan. Taken together, these findings contribute toward understanding the adverse effects of pollutants when present separately or in combination with other types of chemicals.

  10. Effect of multi-walled carbon nanotubes on phytotoxicity of sediments contaminated by phenanthrene and cadmium.

    PubMed

    Song, Biao; Zeng, Guangming; Gong, Jilai; Zhang, Peng; Deng, Jiaqin; Deng, Canhui; Yan, Jin; Xu, Piao; Lai, Cui; Zhang, Chen; Cheng, Min

    2017-04-01

    To implement effective control and abatement programs for contaminants accumulating in sediments, strategies are needed for evaluating the quality of amended sediments. In this study, phytotoxicity of the sediments contaminated by cadmium and phenanthrene was evaluated after in situ remediation with multi-walled carbon nanotubes (MWCNTs) as adsorbents. Adsorption experiments and measurement of aqueous concentrations of the contaminants in overlying water were used to investigate the remediation effectiveness from physical and chemical aspects. The results indicated that MWCNTs showed a much better adsorption performance towards phenanthrene and Cd(II) compared with the sediments. The in situ remediation with MWCNTs could distinctly decrease the aqueous concentrations of phenanthrene and Cd(II) released from the sediments, reducing environmental risk towards overlying water. Influences of MWCNTs dose, MWCNTs diameter, and contact time on phtotoxicity of the contaminated sediments were studied. No significant inhibition of the amended sediments on germination of the test species was observed in the experiments, while the root growth was more sensitive than biomass production to the changes of contaminant concentrations. The analysis of Pearson correlation coefficients between evaluation indicators and associated remediation parameters suggested that phytotoxicity of sediments might inaccurately indicate the changes of pollutant content, but it was significant in reflecting the ecotoxicity of sediments after remediation.

  11. Effects of rhamnolipids on cell surface hydrophobicity of PAH degrading bacteria and the biodegradation of phenanthrene.

    PubMed

    Zhao, Zhenyong; Selvam, Ammaiyappan; Wong, Jonathan Woon-Chung

    2011-03-01

    The effects of rhamnolipids produced by Pseudomonas aeruginosa ATCC9027 on the cell surface hydrophobicity (CSH) and the biodegradation of phenanthrene by two thermophilic bacteria, Bacillus subtilis BUM and P. aeruginosa P-CG3, and mixed inoculation of these two strains were investigated. Rhamnolipids significantly reduced the CSH of the hydrophobic BUM and resulted in a noticeable lag period in the biodegradation. However, they significantly increased the CSH and enhanced the biodegradation for the hydrophilic P-CG3. In the absence of rhamnolipids, a mixed inoculation of BUM and P-CG3 removed 82.2% of phenanthrene within 30 days and the major contributor of the biodegradation was BUM (rapid degrader) while the growth of P-CG3 (slow degrader) was suppressed. Addition of rhamnolipids promoted the surfactant-mediated-uptake of phenanthrene by P-CG3 but inhibited the uptake through direct contact by BUM. This resulted in the domination of P-CG3 during the initial stage of biodegradation and enhanced the biodegradation to 92.7%.

  12. Surface tailored organobentonite enhances bacterial proliferation and phenanthrene biodegradation under cadmium co-contamination.

    PubMed

    Mandal, Asit; Biswas, Bhabananda; Sarkar, Binoy; Patra, Ashok K; Naidu, Ravi

    2016-04-15

    Co-contamination of soil and water with polycyclic aromatic hydrocarbon (PAH) and heavy metals makes biodegradation of the former extremely challenging. Modified clay-modulated microbial degradation provides a novel insight in addressing this issue. This study was conducted to evaluate the growth and phenanthrene degradation performance of Mycobacterium gilvum VF1 in the presence of a palmitic acid (PA)-grafted Arquad® 2HT-75-based organobentonite in cadmium (Cd)-phenanthrene co-contaminated water. The PA-grafted organobentonite (ABP) adsorbed a slightly greater quantity of Cd than bentonite at up to 30mgL(-1) metal concentration, but its highly negative surface charge imparted by carboxylic groups indicated the potential of being a significantly superior adsorbent of Cd at higher metal concentrations. In systems co-contained with Cd (5 and 10mgL(-1)), the Arquad® 2HT-75-modified bentonite (AB) and PA-grafted organobentonite (ABP) resulted in a significantly higher (72-78%) degradation of phenanthrene than bentonite (62%) by the bacterium. The growth and proliferation of bacteria were supported by ABP which not only eliminated Cd toxicity through adsorption but also created a congenial microenvironment for bacterial survival. The macromolecules produced during ABP-bacteria interaction could form a stable clay-bacterial cluster by overcoming the electrostatic repulsion among individual components. Findings of this study provide new insights for designing clay modulated PAH bioremediation technologies in mixed-contaminated water and soil.

  13. High-Capacity and Photoregenerable Composite Material for Efficient Adsorption and Degradation of Phenanthrene in Water.

    PubMed

    Liu, Wen; Cai, Zhengqing; Zhao, Xiao; Wang, Ting; Li, Fan; Zhao, Dongye

    2016-10-18

    We report a novel composite material, referred to as activated charcoal supported titanate nanotubes (TNTs@AC), for highly efficient adsorption and photodegradation of a representative polycyclic aromatic hydrocarbon (PAH), phenanthrene. TNTs@AC was prepared through a one-step hydrothermal method, and is composed of an activated charcoal core and a shell of carbon-coated titanate nanotubes. TNTs@AC offered a maximum Langmuir adsorption capacity of 12.1 mg/g for phenanthrene (a model PAH), which is ∼11 times higher than the parent activated charcoal. Phenanthrene was rapidly concentrated onto TNTs@AC, and subsequently completely photodegraded under UV light within 2 h. The photoregenerated TNTs@AC can then be reused for another adsorption-photodegradation cycle without significant capacity or activity loss. TNTs@AC performed well over a wide range of pH, ionic strength, and dissolved organic matter. Mechanistically, the enhanced adsorption capacity is attributed to the formation of carbon-coated ink-bottle pores of the titanate nanotubes, which are conducive to capillary condensation; in addition, the modified microcarbon facilitates transfer of excited electrons, thereby inhibiting recombination of the electron-hole pairs, resulting in high photocatalytic activity. The combined high adsorption capacity, photocatalytic activity, and regenerability/reusability merit TNTs@AC a very attractive material for concentrating and degrading a host of micropollutants in the environment.

  14. Phenanthrene and pyrene sorption and intraparticle diffusion in polyoxymethylene, coke, and activated carbon.

    PubMed

    Ahn, Sungwoo; Werner, David; Karapanagioti, Hrissi K; McGlothlin, Donald R; Zare, Richard N; Luthy, Richard G

    2005-09-01

    We report sorption isotherms and uptake kinetics for phenanthrene and pyrene with three organic model sorbents: polyoxymethylene (POM), coke, and activated carbon. We combine batch equilibration and kinetic experiments with the direct observation of the long-term diffusion of phenanthrene and pyrene as measured within cross-sectioned particles using microprobe laser-desorption laser-ionization mass spectroscopy (muL2MS). For POM pellets, the intraparticle concentration profiles predicted from kinetic batch experiments and a polymer diffusion model with spherical geometry are in agreement with the independent muL2MS measurements. For coke particles, the apparent diffusivities decreased with smaller particle size. These trends in diffusivities were described by a sorption-retarded pore diffusion model with a particle-size-dependent solid-water partitioning coefficient obtained from apparent equilibrium observed in the kinetic batch studies. For activated carbon, the muL2MS measurements showed faster radial diffusion of phenanthrene and pyrene into the particle interior than predicted from diffusion models based on a single sorption domain and diffusivity. A branched pore kinetic model, comprising polycyclic aromatic hydrocarbon (PAH) macropore diffusion with kinetic exchange of PAH between macroporous and microporous domains, fits the experimental observations better. Because of parallel macro- and microdiffusion processes, nonlinear sorption isotherms, and a concentration-dependent diffusivity, it is not possible to make independent parameter estimations for intraparticle diffusion in activated carbon using our present procedures.

  15. Competitive metabolism of naphthalene, methylnaphthalenes, and fluorene by phenanthrene-degrading pseudomonads

    SciTech Connect

    Stringfellow, W.T.; Aitken, M.D.

    1995-01-01

    Polynuclear aromatic hydrocarbons (PAHs) typically exist as complex mixtures in contaminated soils, yet little is known about the biodegradation of PAHs in mixtures. We have isolated two physiologically diverse bacteria, Pseudomonas stutzeri P-16 and P. saccharophila P-15, from a creosote-contaminated soil by enrichment on phenanthrene as the sole carbon source and studied their ability to metabolize several other two- and three-ring PAHs. Naphthalene, 1-methylnaphthalene, and 2-methylnaphthalene served as growth substrates for both organisms, while fluorene was only cometabolized. We also studied the effects of these compounds on initial rates of phenanthrene uptake in binary mixtures. Lineweaver-Burk analysis of kinetic measurements was used to demonstrate competitive inhibition of phenanthrene uptake by all four compounds, suggesting that multiple PAHs are being transformed by a common enzyme pathway in whole cells. Estimates of the inhibition coefficient, K{sub i}, are reported for each compound. The occurrence of competitive metabolic processes in physiologically diverse organisms suggests that competitive metabolism may be a common phenomenon among PAH-degrading organisms. 44 refs., 3 figs., 4 tabs.

  16. Effect of a commercial alcohol ethoxylate surfactant (C11-15E7) on biodegradation of phenanthrene in a saline water medium by Neptunomonas naphthovorans.

    PubMed

    Li, Jing-Liang; Bai, Renbi

    2005-02-01

    Biodegradation of poorly soluble polycyclic aromatic hydrocarbons (PAHs) has been a challenge in bioremediation. In recent years, surfactant-enhanced bioremediation of PAH contaminants has attracted great attention in research. In this study, biodegradation of phenanthrene as a model PAHs solubilized in saline micellar solutions of a biodegradable commercial alcohol ethoxylate nonionic surfactant was investigated. The critical micelle concentration (CMC) of the surfactant and its solubilization capacity for phenanthrene were examined in an artificial saline water medium, and a type of marine bacteria, Neptunomonas naphthovorans, was studied for the biodegradation of phenanthrene solubilized in the surfactant micellar solutions of the saline medium. It is found that the solubility of phenanthrene in the surfactant micellar solutions increased linearly with the surfactant concentrations, but, at a fixed phenanthrene concentration, the biodegradability of phenanthrene in the micellar solutions decreased with the increase of the surfactant concentrations. This was attributed to the reduced bioavailability of phenanthrene, due to its increased solubilization extent in the micellar phase and possibly lowered mass transfer rate from the micellar phase into the aqueous phase or into the bacterial cells. In addition, an inhibitory effect of the surfactant on the bacterial growth at high surfactant concentrations may also play a role. It is concluded that the surfactant largely enhanced the solubilization of phenanthrene in the saline water medium, but excess existence of the surfactant in the medium should be minimized or avoided for the biodegradation of phenanthrene by Neptunomonas naphthovorans.

  17. Molecular characteristics of humic acids isolated from vermicomposts and their relationship to bioactivity.

    PubMed

    Martinez-Balmori, Dariellys; Spaccini, Riccardo; Aguiar, Natália Oliveira; Novotny, Etelvino Henrique; Olivares, Fábio Lopes; Canellas, Luciano Pasqualoto

    2014-11-26

    Vermitechnology is an effective composting method, which transforms biomass into nutrient-rich organic fertilizer. Mature vermicompost is a renewable organic product containing humic substances with high biological activity. The aim of this study was to assess the chemical characteristics and the bioactivity of humic acids isolated from different vermicomposts produced with either cattle manure, sugar cane bagasse, sunflower cake from seed oil extraction, or filter cake from a sugar cane factory. More than 200 different molecules were found, and it was possible to identify chemical markers on humic acids according to the nature of the organic source. The large hydrophobic character of humic extracts and the preservation of altered lignin derivatives confer to humic acids the ability to induce lateral root emergence in maize seedlings. Humic acid-like substances extracted from plant biomass residues represent an additional valuable product of vermicomposting that can be used as a plant growth promoter.

  18. Root-Shoot Signaling crosstalk involved in the shoot growth promoting action of rhizospheric humic acids

    PubMed Central

    Olaetxea, Maite; Mora, Verónica; García, Andrés Calderin; Santos, Leandro Azevedo; Baigorri, Roberto; Fuentes, Marta; Garnica, María; Berbara, Ricardo Luis Louro; Zamarreño, Angel Maria; Garcia-Mina, Jose M.

    2016-01-01

    ABSTRACT Numerous studies have shown the ability of humic substances to improve plant development. This action is normally reflected in an enhancement of crop yields and quality. However, the mechanisms responsible for this action of humic substances remain rather unknown. Our studies have shown that the shoot promoting action of sedimentary humic acids is dependent of its ability to increase root hydraulic conductivity through signaling pathways related to ABA, which in turn is affected in roots by humic acids in an IAA-NO dependent way. Furthermore, these studies also indicate that the primary action of humic acids in roots might also be physical, resulting from a transient mild stress caused by humic acids associated with a fouling-cleaning cycle of wall cell pores. Finally the role of alternative signal molecules, such as ROS, and corresponding signaling pathways are also discussed and modeled in the context of the above-mentioned framework. PMID:26966789

  19. Determination of soluble aluminium concentration in alkaline humic water using atomic absorption spectrophotometry.

    PubMed

    Nguyen, K L; Lewis, D M; Jolly, M; Robinson, J

    2004-11-01

    The steps of the standard method to determine soluble aluminium concentration are filtering, followed by acidifying, then analysing with the atomic absorption spectrophotometer (AAS). When applied to alkaline humic water, acidification gives rise to the formation of humic acid as a brown particulate matter. Of the total soluble aluminium in the original water, 49-61% forms complexes with the particulate humic acid upon acidification. Although the AAS is capable of detecting the binding aluminium, the particulate nature of humic acid easily induces inaccurate readings as a result of the non-uniform distribution of the particulate matter. A more precise analysis of soluble aluminium concentration of alkaline humic water is shown to be achievable in basicified solutions instead. Basicified solutions keep humic acid in the soluble form; hence maintain the homogeneity of the sample.

  20. Removal of humic substances from water by brown coal sorbents

    SciTech Connect

    E.V. Veprikova; A.V. Rudkovskii; M.L. Shchipko

    2007-12-15

    Brown coal sorption materials with high activity toward humic substances were prepared using a larger scale laboratory unit with a spouted-bed system. The effect of thermal treatment conditions on the sorption properties of these materials was studied. It was found that the sorption activity of the resulting samples toward humates was closely related to the limiting sorption volume of the materials with respect to benzene.

  1. Role of microbial adhesion in phenanthrene biodegradation by Pseudomonas fluorescens LP6a

    NASA Astrophysics Data System (ADS)

    Abbasnezhad, Hassan

    Biodegradation of poorly water soluble hydrocarbons, such as n-alkanes and polycyclic aromatic hydrocarbons (PAHs) is often limited by the low availability of the pollutant to microbes. Adhesion of microorganisms to the oil-water interface can influence this availability. Our approach was to study a range of compounds and mechanisms to promote the adhesion of a hydrophilic PAH degrading bacterium, Pseudomonas fluorescens LP6a, to an oil-water interface and examine the effect on biodegradation of phenanthrene by the bacteria. The cationic surfactants cetylpyridinium chloride (CPC), poly-L-lysine and chlorhexidine gluconate (CHX) and the long chain alcohols 1-dodecanol, 2-dodecanol and farnesol increased the adhesion of P. fluorescens LP6a to n-hexadecane from ca. 30% to ca. 90% of suspended cells adhering. The alcohols also caused a dramatic change in the oil-water contact angle of the cell surface, increasing it from 24° to 104°, whereas the cationic compounds had little effect. In contrast, cationic compounds changed the electrophoretic mobility of the bacteria, reducing the mean zeta potential from --23 to --7 mV in 0.01M potassium phosphate buffer, but the alcohols had no effect on zeta potential. This results illustrate that alcohols acted through altering the cell surface hydrophobicity, whereas cationic surfactants changed the surface charge density. Phenanthrene was dissolved in heptamethylnonane and introduced to the aqueous growth medium, hence forming a two phase system. Introducing 1-dodecanol at concentrations of 217, 820 or 4100 mg/L resulted in comparable increases in phenanthrene biodegradation of about 30% after 120 h incubation with non-induced cultures. After 100 h of incubation with LP6a cultures induced with 2-aminobenzoate, 4.5% of the phenanthrene was mineralized by cultures versus more than 10% by the cultures containing initial 1-dodecanol or 2-dodecanol concentrations of 120 or 160 mg/L. The production and accumulation of metabolites in

  2. Interactions of Tc(IV) with humic substances

    SciTech Connect

    Boggs, M. A.; Minton, Travis; Lomasney, Samuel; Islam, Mohammed; Dong, Wenming; Gu, Baohua; Wall, Nathalie

    2011-01-01

    To understand the key processes affecting 99Tc mobility in the subsurface and help with the remediation of contaminated sites, the binding constants of several humic substances (humic and fulvic acids) with Tc(IV) were determined, using a solvent extraction technique. The novelty of this paper lies in the determination of the binding constants of the complexes formed with the individual species TcO(OH)+ and TcO(OH)20. Binding constants were found to be 6.8 and between 3.9 and 4.3, for log 1, 1,1 and log 1,-2,1, respectively; these values were little modified by a change of ionic strength, in most cases, between 0.1 M to 1.0 M, nor were they by the nature and origin of the humic substances. Modeling calculations based on these show TcO(OH)-HA to be the predominant complex in a system containing 20 ppm HA and in the 4-6 pH range, while TcO(OH)20 and TcO(OH)2-HA are the major species, in the pH 6-8 range.

  3. Nitrogen incorporation into lignite humic acids during microbial degradation

    SciTech Connect

    Dong, L.H.; Yuan, H.L.

    2009-07-01

    Previous study showed that nitrogen content in lignite humic acids (HA) increased significantly during lignite biodegradation. In this paper we evaluated the factors responsible for the increased level of N in HA and the formation of new nitrogen compound following microbial degradation. When the ammonium sulfate concentration in lignite medium was 0.5%, the N-content in HA was higher than that in the crude lignite humic acid (cHA); when the ammonium sulfate concentration was epsilon 0.5%, both the biodegraded humic acid (bHA) N-content and the content of bHA in lignite increased significantly, but at 2.0% no increase was observed. This indicated that HA incorporated N existing in the lignite medium, and more HA can incorporate more N with the increase of bHA amount in lignite during microbial degradation. CP/MAS {sup 15}N NMR analysis showed that the N incorporated into HA during biotransformation was in the form of free or ionized NH{sub 2}-groups in amino acids and sugars, as well as NH{sub 4}{sup +}. We propose nitrogen can be incorporated into HA biotically and abiotically. The high N content bHA has a potential application in agriculture since N is essential for plant growth.

  4. AhR-mediated and antiestrogenic activity of humic substances.

    PubMed

    Janosek, J; Bittner, M; Hilscherová, K; Bláha, L; Giesy, J P; Holoubek, I

    2007-04-01

    Humic substances (HS) were for decades regarded as inert in the ecosystems with respect to their possible toxicity. However, HS have been recently shown to elicit various adverse effects generally attributed to xenobiotics. In our study, we used MVLN and H4IIE-luc cell lines stably transfected with luciferase gene under control of estrogen receptor (ER) and Ah receptor (AhR; receptor connected with so-called dioxin-like toxicity) for assessment of anti/estrogenic and AhR-mediated effects of 12 commercially available humic substances. Out of those, five humic acids were shown to induce AhR-mediated activity with relative potencies related to TCDD 2.6 x 10(-8)-7.4 x 10(-8). Organic extracts of HS solutions also elicited high activities what means that lipophilic molecules are responsible for a great part of effect. However, relatively high activity remaining in extracted solution suggests also presence of polar AhR-agonists. Contribution of persistent organic compounds to the observed effects was ruled out by H(2)SO(4) treatment. Eight out of twelve HS elicited significant antiestrogenic effects with IC(50) ranging from 40 to 164 mg l(-1). The possible explanations of the antiestrogenic effect include sorption of 17-beta-estradiol (E2) on HS, changes in membrane permeability for E2 or another specific mechanism.

  5. Covalent binding of aniline to humic substances. 1. Kinetic studies

    USGS Publications Warehouse

    Weber, E.J.; Spidle, D.L.; Thorn, K.A.

    1996-01-01

    The reaction kinetics for the covalent binding of aniline with reconstituted IHSS humic and fulvic acids, unfractionated DOM isolated from Suwannee River water, and whole samples of Suwannee River water have been investigated. The reaction kinetics in each of these systems can be adequately described by a simple second-order rate expression. The effect of varying the initial concentration of aniline on reaction kinetics suggested that approximately 10% of the covalent binding sites associated with Suwannee River fulvic acid are highly reactive sites that are quickly saturated. Based on the kinetic parameters determined for the binding of aniline with the Suwannee River fulvic and humic acid isolates, it was estimated that 50% of the aniline concentration decrease in a Suwannee River water sample could be attributed to reaction with the fulvic and humic acid components of the whole water sample. Studies with Suwannee River fulvic acid demonstrated that the rate of binding decreased with decreasing pH, which parallels the decrease in the effective concentration of the neutral form, or reactive nucleophilic species of aniline. The covalent binding of aniline with Suwannee River fulvic acid was inhibited by prior treatment of the fulvic acid with hydrogen sulfide, sodium borohydride, or hydroxylamine. These observations are consistent with a reaction pathway involving nucleophilic addition of aniline to carbonyl moieties present in the fulvic acid.

  6. Some effects of ozonation of humic substances in drinking water

    NASA Astrophysics Data System (ADS)

    Hongve, Dag; Lund, Vidar; Åkesson, Gunvor; Becher, Georg

    Ozonation is employed as a method for removal of colour due to humic substances in drinking water. We have examined some effects of ozonation of humic water in the laboratory. Ozonation reduced colour by 80% but had little influence on the DOC concentration and only moderate effect on the UV absorbance at 254 nm. High-performance size-exclusion chromatography (HPSEC) showed that the content of high-molecular-weight substances was reduced while a nearly corresponding amount of low-molecular-weight compounds was produced. The produced substances have acidic properties, are uncoloured and do not absorb UV light at 254 nm. Ozonation also led to higher BOD values. The formed low-molecular-weight compounds were consumed by microorganisms. In the original humic water sample the microbial degradation affected only high-molecular-weight compounds. The higher content of biodegradable organic compounds in ozonated drinking water is probably responsible for accelerated growth of bacteria and production of sludge in the distribution systems of a Norwegian waterwork. The obtained colour reduction seems to be temporary, since the colour of ozonated water increases under the influence of microorganisms.

  7. Complexation of copper by aquatic humic substances from different environments

    USGS Publications Warehouse

    McKnight, Diane M.; Feder, Gerald L.; Thurman, E. Michael; Wershaw, Robert L.

    1983-01-01

    The copper-complexing properties of aquatic humic substances isolated from eighteen different environments were characterized by potentiometric titration, using a cupric ion selective electrode. Potentiometric data were analyzed using FITEQL, a computer program for the determination of chemical equilibrium constants from experimental data. All the aquatic humic substances could be modelled as having two types of Cu(II)-binding sites: one with K equal to about 106 and a concentration of 1.0 ± 0.4 × 10−6 M(mg C)−1 and another with K equal to about 108 and a concentration of 2.6 ± 1.6 × 10−7 M(mg C)−1.A method is described for estimating the Cu(II)-binding sites associated with dissolved humic substances in natural water based on a measurement of dissolved organic carbon, which may be helpful in evaluating chemical processes controlling speciation of Cu and bioavailability of Cu to aquatic organisms.

  8. Sorption of tebuconazole onto selected soil minerals and humic acids.

    PubMed

    Cadková, Eva; Komárek, Michael; Kaliszová, Regina; Koudelková, Věra; Dvořák, Jiří; Vaněk, Aleš

    2012-01-01

    The aim of the present study was to investigate tebuconazole sorption on common soil minerals (birnessite, ferrihydrite, goethite, calcite and illite) and humic acids (representing soil organic matter). Tebuconazole was used (i) in the commercial form Horizon 250 EW and (ii) as an analytical grade pure chemical. In the experiment with the commercially available tebuconazole, a significant pH-dependent sorption onto the oxides was observed (decreasing sorption with increasing pH). The highest sorption was found for ferrihydrite due to its high specific surface area, followed by humic acids, birnessite, goethite and illite. No detectable sorption was found for calcite. The sorption of analytical grade tebuconazole on all selected minerals was significantly lower compared to the commercial product. The sorption was the highest for humic acids, followed by ferrihydrite and illite and almost negligible for goethite and birnessite without any pH dependence. Again, no sorption was observed for calcite. The differences in sorption of the commercially available and analytical grade tebuconazole can be attributed to the additives (e.g., solvents) present in the commercial product. This work proved the importance of soil mineralogy and composition of the commercially available pesticides on the behavior of tebuconazole in soils.

  9. Bioconcentration of phenanthrene and metabolites in bile and behavioral alterations in the tropical estuarine guppy Poecilia vivipara.

    PubMed

    Torreiro-Melo, Anny Gabrielle A G; Silva, Juliana Scanoni; Bianchini, Adalto; Zanardi-Lamardo, Eliete; de Carvalho, Paulo Sérgio Martins

    2015-08-01

    Quantification of polycyclic aromatic hydrocarbon (PAH) metabolites in fish bile is widely used to evaluate levels of internal PAH contamination in fish, whereas behavioral effects are deemed important to address potential risks to fish populations. The estuarine guppy Poecilia vivipara was exposed for 96h to waterborne phenanthrene at concentrations of 10, 50, 200 and 500μgL(-1). Phenanthrene and metabolites in bile were analyzed by fixed fluorescence at 260/380nm (excitation/emission) wavelengths. Phenanthrene increased in the bile of exposed fish in a dose-dependent pattern, and log bile bioconcentration factors ranged from 4.3 to 3.9 at 10 and 500μgL(-1) phenanthrene, respectively, values that are similar to predicted bioconcentration factors based on phenanthrene Kow. Swimming resistance index was reduced to 81% of control values at 500μgL(-1). Alteration of swimming speed was non monotonic, with a significant speed increase relative to control fish in treatments 50 and 200μgL(-1) phenanthrene, respectively, followed by a speed decrease in fish exposed to 500μgL(-1). However, swimming trajectories of fish exposed to 50, 200 and 500μgL(-1) was altered by the development of a repetitive circular swimming behavior, in contrast to the controls that explored the entire experimental arena. This change in swimming patterns apparently explains the reduction in prey capture rates at 200μgL(-1) phenanthrene. This study provides important information enabling the use of the estuarine guppy P. vivipara to monitor PAH metabolites in bile and its bioconcentration, linking internal exposure with ecologically relevant behavioral effects in the species.

  10. Comparing the desorption and biodegradation of low concentrations of phenanthrene sorbed to activated carbon, biochar and compost.

    PubMed

    Marchal, Geoffrey; Smith, Kilian E C; Rein, Arno; Winding, Anne; Trapp, Stefan; Karlson, Ulrich G

    2013-02-01

    Carbonaceous soil amendments are applied to contaminated soils and sediments to strongly sorb hydrophobic organic contaminants (HOCs) and reduce their freely dissolved concentrations. This limits biouptake and toxicity, but also biodegradation. To investigate whether HOCs sorbed to such amendments can be degraded at all, the desorption and biodegradation of low concentrations of (14)C-labelled phenanthrene (≤5 μg L(-1)) freshly sorbed to suspensions of the pure soil amendments activated carbon (AC), biochar (charcoal) and compost were compared. Firstly, the maximum abiotic desorption of phenanthrene from soil amendment suspensions in water, minimal salts medium (MSM) or tryptic soy broth (TSB) into a dominating silicone sink were measured. Highest fractions remained sorbed to AC (84±2.3%, 87±4.1%, and 53±1.2% for water, MSM and TSB, respectively), followed by charcoal (35±2.2%, 32±1.7%, and 12±0.3%, respectively) and compost (1.3±0.21%, similar for all media). Secondly, the mineralization of phenanthrene sorbed to AC, charcoal and compost by Sphingomonas sp. 10-1 (DSM 12247) was determined. In contrast to the amounts desorbed, phenanthrene mineralization was similar for all the soil amendments at about 56±11% of the initially applied radioactivity. Furthermore, HPLC analyses showed only minor amounts (<5%) of residual phenanthrene remaining in the suspensions, indicating almost complete biodegradation. Fitting the data to a coupled desorption and biodegradation model revealed that desorption did not limit biodegradation for any of the amendments, and that degradation could proceed due to the high numbers of bacteria and/or the production of biosurfactants or biofilms. Therefore, reduced desorption of phenanthrene from AC or charcoal did not inhibit its biodegradation, which implies that under the experimental conditions these amendments can reduce freely dissolved concentration without hindering biodegradation. In contrast, phenanthrene sorbed to compost

  11. Trinuclear nickel coordination complexes of phenanthrene-9,10-dione dioxime.

    PubMed

    Williams, Owen M; Cowley, Alan H

    2016-04-01

    A trinuclear nickel complex of phenanthrene-9,10-dione dioxime (H2pqd), namely bis-[μ2-9,10-bis-(oxido-imino)-phenanthrene]-bis-[μ2-10-(oxido-imino)phenanthrene-9-one oxime](phenanthrene-9,10-dione dioxime)trinickel(II) toluene disolvate, [Ni3(C14H8N2O2)2(C14H9N2O2)2(C14H10N2O2)]·2C7H8, has been isolated and its crystal structure determined. This complex features three independent Ni(II) atoms that are arranged in a triangular fashion along with five supporting ligands. There are two square-planar Ni(II) atoms and a third pseudo-octa-hedral Ni(II) atom. While the square-planar Ni(II) atoms are stacked, there are no ligand bridges between them. Each square-planar Ni(II) atom, however, bridges with the pseudo-octa--hedral Ni(II) atom through Ni-N-O-Ni and Ni-O-Ni bonds. A fluorido-bor-ation reaction of the proton-bridged species gave the analogous complex bis-(μ2-bis-{[10-(oxido-imino)-9,10-di-hydro-phenanthren-9-yl-idene]amino}di-fluorido-borato)(phenanthrene-9,10-dione dioxime)trinickel(II) dichloromethane trisolvate, [Ni3(C28H16BF2N4O2)4(C14H10N2O2)]·3CH2Cl2, which shows the same binding structure, but features a widened Ni-Ni inter-action between the square-planar Ni(II) atoms. The proton-bridged complex completes the macrocyclic coordination around the square-planar Ni(II) atoms by means of an O-H⋯O hydrogen bond. Both compounds feature O-H⋯N hydrogen bonds between the oxime and the N atoms attached to square-planar nickel atom. The nickel units show no direct inter-action with their nearest neighbors in the extended lattice. Two π-stacking inter-actions between adjacent mol-ecules are found: one with a centroid-centroid distance of 3.886 (2) Å and the other with a centroid-centroid distance of 4.256 (3) Å. In the latter case, although not aromatic, the distance to the centroid of the central phenanthrene ring is shorter, with a distance of 3.528 (3) Å. Toluene mol-ecules occupy the solvent channels that are oriented along the c axis. In

  12. Trinuclear nickel coordination complexes of phenanthrene-9,10-dione dioxime

    PubMed Central

    Williams, Owen M.; Cowley, Alan H.

    2016-01-01

    A trinuclear nickel complex of phenanthrene-9,10-dione dioxime (H2pqd), namely bis­[μ2-9,10-bis­(oxido­imino)­phenanthrene]­bis­[μ2-10-(oxido­imino)phenanthrene-9-one oxime](phenanthrene-9,10-dione dioxime)trinickel(II) toluene disolvate, [Ni3(C14H8N2O2)2(C14H9N2O2)2(C14H10N2O2)]·2C7H8, has been isolated and its crystal structure determined. This complex features three independent NiII atoms that are arranged in a triangular fashion along with five supporting ligands. There are two square-planar NiII atoms and a third pseudo-octa­hedral NiII atom. While the square-planar NiII atoms are stacked, there are no ligand bridges between them. Each square-planar NiII atom, however, bridges with the pseudo-octa­­hedral NiII atom through Ni—N—O—Ni and Ni—O—Ni bonds. A fluorido­bor­ation reaction of the proton-bridged species gave the analogous complex bis­(μ2-bis­{[10-(oxido­imino)-9,10-di­hydro­phenanthren-9-yl­idene]amino}di­fluorido­borato)(phenanthrene-9,10-dione dioxime)trinickel(II) dichloromethane trisolvate, [Ni3(C28H16BF2N4O2)4(C14H10N2O2)]·3CH2Cl2, which shows the same binding structure, but features a widened Ni—Ni inter­action between the square-planar NiII atoms. The proton-bridged complex completes the macrocyclic coordination around the square-planar NiII atoms by means of an O—H⋯O hydrogen bond. Both compounds feature O—H⋯N hydrogen bonds between the oxime and the N atoms attached to square-planar nickel atom. The nickel units show no direct inter­action with their nearest neighbors in the extended lattice. Two π-stacking inter­actions between adjacent mol­ecules are found: one with a centroid–centroid distance of 3.886 (2) Å and the other with a centroid–centroid distance of 4.256 (3) Å. In the latter case, although not aromatic, the distance to the centroid of the central phenanthrene ring is shorter, with a distance of 3.528 (3) Å. Toluene mol­ecules occupy the solvent channels that are

  13. Behavioural alterations from exposure to Cu, phenanthrene, and Cu-phenanthrene mixtures: linking behaviour to acute toxic mechanisms in the aquatic amphipod, Hyalella azteca.

    PubMed

    Gauthier, Patrick T; Norwood, Warren P; Prepas, Ellie E; Pyle, Greg G

    2016-01-01

    Phenanthrene (PHE) and Cu are two contaminants commonly co-occurring in marine and freshwater environments. Mixtures of PHE and Cu have been reported to induce more-than-additive lethality in the amphipod, Hyalella azteca, a keystone aquatic invertebrate, yet little is understood regarding the interactive toxic mechanisms that mediate more-than-additive toxicity. Understanding the interactions among toxic mechanisms among Cu and PHE will allow for better predictive power in assessing the ecological risks of Cu-PHE mixtures in aquatic environments. Here we use behavioural impairment to help understand the toxic mechanisms of Cu, PHE, and Cu-PHE mixture toxicity in the aquatic amphipod crustacean, Hyalella azteca. Our principal objective was to link alterations in activity and ventilation with respiratory rates, oxidative stress, and neurotoxicity in adult H. azteca. Adult amphipods were used for all toxicity tests. Amphipods were tested at sublethal exposures of 91.8- and 195-μgL(-1) Cu and PHE, respectively, and a Cu-PHE mixture at the same concentrations for 24h. Neurotoxicity was measured as acetylcholinesterase (AChE) activity, where malathion was used as a positive control. Oxidative stress was measured as reactive oxygen species (ROS) production. Phenanthrene-exposed amphipods exhibited severe behavioural impairment, being hyperstimulated to the extent that they were incapable of coordinating muscle movements. In addition, respiration and AChE activity in PHE-exposed amphipods were increased and reduced by 51% and 23% respectively. However, ROS did not increase following exposure to phenanthrene. In contrast, Cu had no effect on amphipod behaviour, respiration or AChE activity, but did lead to an increase in ROS. However, co-exposure to Cu antagonized the PHE-induced reduction in ventilation and negated any increase in respiration. The results suggest that PHE acts like an organophosphate pesticide (e.g., malathion) in H. azteca following 24h sublethal

  14. Isolation, plant colonization potential, and phenanthrene degradation performance of the endophytic bacterium Pseudomonas sp. Ph6-gfp.

    PubMed

    Sun, Kai; Liu, Juan; Gao, Yanzheng; Jin, Li; Gu, Yujun; Wang, Wanqing

    2014-06-26

    This investigation provides a novel method of endophyte-aided removal of polycyclic aromatic hydrocarbons (PAHs) from plant bodies. A phenanthrene-degrading endophytic bacterium Pseudomonas sp. Ph6 was isolated from clover (Trifolium pratense L.) grown in a PAH-contaminated site. After being marked with the GFP gene, the colonization and distribution of strain Ph6-gfp was directly visualized in plant roots, stems, and leaves for the first time. After ryegrass (Lolium multiflorum Lam.) roots inoculation, strain Ph6-gfp actively and internally colonized plant roots and transferred vertically to the shoots. Ph6-gfp had a natural capacity to cope with phenanthrene in vitro and in planta. Ph6-gfp degraded 81.1% of phenanthrene (50 mg · L(-1)) in a culture solution within 15 days. The inoculation of plants with Ph6-gfp reduced the risks associated with plant phenanthrene contamination based on observations of decreased concentration, accumulation, and translocation factors of phenanthrene in ryegrass. Our results will have important ramifications in the assessment of the environmental risks of PAHs and in finding ways to circumvent plant PAH contamination.

  15. Isolation and characterization of a novel phenanthrene (PHE) degrading strain Psuedomonas sp. USTB-RU from petroleum contaminated soil.

    PubMed

    Masakorala, Kanaji; Yao, Jun; Cai, Minmin; Chandankere, Radhika; Yuan, Haiyan; Chen, Huilun

    2013-12-15

    The phenanthrene degrading novel bacterium strain USTB-RU was isolated from petroleum contaminated soil in Dagan oilfield, southeast of Tianjin, northeast China. The novel isolate was identified as Pseudomonas sp. USTB-RU on the basis of morphological, physicochemical characteristics and analysis of 16S rDNA gene sequence. The strain could degrade 86.65% of phenanthrene at an initial concentration of 100 mg L(-1) in 8 days and identified intermediate metabolite evident the biodegradation of phenanthrene through protocatechuate metabolic pathway. The strain showed the potential to produce surface-active compounds that may have caused for the resulted efficient biodegradation through enhancing the substrate bioavailability. The results highlighted that the adaptability of USTB-RU to grow in a range of temperature, pH and potential to utilize various commonly co-exist pollutants in contaminated site other than phenanthrene as sole carbon and energy source. Further, susceptibility of the strain for the tested antibiotics inferred the possibility to absence of risk of spreading drug resistant factor to other indigenous bacteria. Therefore, the isolated novel strain USTB-RU may have a high potential for application in in situ bioremediation of phenanthrene contaminated environment.

  16. Comparative proteomics reveal the mechanism of Tween80 enhanced phenanthrene biodegradation by Sphingomonas sp. GY2B.

    PubMed

    Liu, Shasha; Guo, Chuling; Dang, Zhi; Liang, Xujun

    2017-03-01

    Previous study concerning the effects of surfactants on phenanthrene biodegradation focused on observing the changes of cell characteristics of Sphingomonas sp. GY2B. However, the impact of surfactants on the expression of bacterial proteins, controlling phenanthrene transport and catabolism, remains obscure. To overcome the knowledge gap, comparative proteomic approaches were used to investigate protein expressions of Sphingomonas sp. GY2B during phenanthrene biodegradation in the presence and absence of a nonionic surfactant, Tween80. A total of 23 up-regulated and 19 down-regulated proteins were detected upon Tween80 treatment. Tween80 could regulate ion transport (e.g. H(+)) in cell membrane to provide driving force (ATP) for the transmembrane transport of phenanthrene thus increasing its uptake and biodegradation by GY2B. Moreover, Tween80 probably increased GY2B vitality and growth by inducing the expression of peptidylprolyl isomerase to stabilize cell membrane, increasing the abundances of proteins involved in intracellular metabolic pathways (e.g. TCA cycle), as well as decreasing the abundances of translation/transcription-related proteins and cysteine desulfurase, thereby facilitating phenanthrene biodegradation. This study may facilitate a better understanding of the mechanisms that regulate surfactants-enhanced biodegradation of PAHs at the proteomic level.

  17. Isolation, plant colonization potential, and phenanthrene degradation performance of the endophytic bacterium Pseudomonas sp. Ph6-gfp

    NASA Astrophysics Data System (ADS)

    Sun, Kai; Liu, Juan; Gao, Yanzheng; Jin, Li; Gu, Yujun; Wang, Wanqing

    2014-06-01

    This investigation provides a novel method of endophyte-aided removal of polycyclic aromatic hydrocarbons (PAHs) from plant bodies. A phenanthrene-degrading endophytic bacterium Pseudomonas sp. Ph6 was isolated from clover (Trifolium pratense L.) grown in a PAH-contaminated site. After being marked with the GFP gene, the colonization and distribution of strain Ph6-gfp was directly visualized in plant roots, stems, and leaves for the first time. After ryegrass (Lolium multiflorum Lam.) roots inoculation, strain Ph6-gfp actively and internally colonized plant roots and transferred vertically to the shoots. Ph6-gfp had a natural capacity to cope with phenanthrene in vitro and in planta. Ph6-gfp degraded 81.1% of phenanthrene (50 mg.L-1) in a culture solution within 15 days. The inoculation of plants with Ph6-gfp reduced the risks associated with plant phenanthrene contamination based on observations of decreased concentration, accumulation, and translocation factors of phenanthrene in ryegrass. Our results will have important ramifications in the assessment of the environmental risks of PAHs and in finding ways to circumvent plant PAH contamination.

  18. Quantifying the biodegradation of phenanthrene by Pseudomonas stutzeri P16 in the presence of a nonionic surfactant.

    PubMed Central

    Grimberg, S J; Stringfellow, W T; Aitken, M D

    1996-01-01

    The low water solubility of polycyclic aromatic hydrocarbons is believed to limit their availability to microorganisms, which is a potential problem for bioremediation of polycyclic aromatic hydrocarbon-contaminated sites. Surfactants have been suggested to enhance the bioavailability of hydrophobic compounds, but both negative and positive effects of surfactants on biodegradation have been reported in the literature. Earlier, we presented mechanistic models of the effects of surfactants on phenanthrene dissolution and on the biodegradation kinetics of phenanthrene solubilized in surfactant micelles. In this study, we combined the biodegradation and dissolution models to quantify the influence of the surfactant Tergitol NP-10 on biodegradation of solid-phase phenanthrene by Pseudomonas stutzeri P16. Although micellized phenanthrene does not appear to be available directly to the bacterium, the ability of the surfactant to increase the phenanthrene dissolution rate resulted in an overall increase in bacterial growth rate in the presence of the surfactant. Experimental observations could be predicted well by the derived model with measured biokinetic and dissolution parameters. The proposed model therefore can serve as a base case for understanding the physical-chemical effects of surfactants on nonaqueous hydrocarbon bioavailability. PMID:8779577

  19. [Forming mechanism of humic acid-kaolin complexes and the adsorption of trichloroethylene].

    PubMed

    Zhu, Xiao-jing; He, Jiang-tao; Su, Si-hui

    2015-01-01

    The interaction between soil organic components and mineral components was explored in this study. Humic acid and kaolin were used for the preparation of organic-mineral complexes with different contents of organic matter, for experimental study of the adsorption of trichloroethylene. The results showed that the adsorption of trichlorethylene fitted the Freundlich isotherm model. The existence of interaction between humic acid and kaolin was indicated by the significant difference between the actual value and the theoretically overlaid value of the adsorption capacity. With various characterizations, such as FTIR and surface area & pore analysis, the mechanism of interaction between humic acid and kaolin was suggested as follows. When their contents were low, humic acid molecules firstly loaded on the surface binding sites of kaolin. Then with the content increased, as O/M( organic-mineral mass ratio) was 0.02-0.04, some surface pores of kaolin were filled by part of the molecules. After reaching a relatively stable stage, as O/M was 0.04-0.08, humic molecules continued to load on the surface of kaolin and formed the first humic molecule-layer. With humic acid content continued increasing, as O/M was 0.08-0.10, more humic molecules attached to kaolin surface through the interaction with the first layer of molecules and then formed the second layer. O/M was 0.10-0.16 as the whole second layer stage, meanwhile the first layer was compressed. Then when O/M was 0.16-0.4, there were still some humic loadings onto the second layer as the third layer, and further compressed the inner humic acid layers. Besides, some humic acid molecules or aggregates might go on attaching to form as further outer layer.

  20. The lanthanum precipitation method. Part 1: a new method for technetium(IV) speciation in humic rich natural groundwater.

    PubMed

    Geraedts, K; Maes, A

    2008-09-01

    A new and quick method for direct speciation of Tc(IV) in humic rich solutions, based on the induced aggregation of humic substances in the presence of the trivalent cation La3+, is presented. This method (the "La-precipitation method") allows flocculating all the humic substances and also the Tc(IV) associated with humic substances. The method is tested on solutions containing Tc(IV) and Gorleben humic substances. The influence of different parameters (humic substance concentration, Tc concentration, reaction time and pH) is investigated on the observed free Tc(IV) concentration after precipitation of all humic substances. None of these parameters had a (significant) influence on the observed Tc(IV) concentration in solution after addition of La3+ to Tc(IV)-HS containing solutions. It is therefore proposed that the method can be used to separate the Tc(IV) bound to humic substances from the free inorganic Tc species in solution.

  1. Metabolism of a Representative Oxygenated Polycyclic Aromatic Hydrocarbon (PAH) Phenanthrene-9,10-quinone in Human Hepatoma (HepG2) Cells

    PubMed Central

    2014-01-01

    Exposure to polycyclic aromatic hydrocarbons (PAHs) in the food chain is the major human health hazard associated with the Deepwater Horizon oil spill. Phenanthrene is a representative PAH present in crude oil, and it undergoes biological transformation, photooxidation, and chemical oxidation to produce its signature oxygenated derivative, phenanthrene-9,10-quinone. We report the downstream metabolic fate of phenanthrene-9,10-quinone in HepG2 cells. The structures of the metabolites were identified by HPLC–UV–fluorescence detection and LC–MS/MS. O-mono-Glucuronosyl-phenanthrene-9,10-catechol was identified, as reported previously. A novel bis-conjugate, O-mono-methyl-O-mono-sulfonated-phenanthrene-9,10-catechol, was discovered for the first time, and evidence for both of its precursor mono conjugates was obtained. The identities of these four metabolites were unequivocally validated by comparison to authentic enzymatically synthesized standards. Evidence was also obtained for a minor metabolic pathway of phenanthrene-9,10-quinone involving bis-hydroxylation followed by O-mono-sulfonation. The identification of 9,10-catechol conjugates supports metabolic detoxification of phenanthrene-9,10-quinone through interception of redox cycling by UGT, COMT, and SULT isozymes and indicates the possible use of phenanthrene-9,10-catechol conjugates as biomarkers of human exposure to oxygenated PAH. PMID:24646012

  2. Effect of pressure on solid-liquid equilibrium for decane + octacosane, decane + p-xylene + octacosane, and decane + p-xylene + phenanthrene mixtures

    SciTech Connect

    Lee, Hyoguk; Groves, F.R.; Wolcott, J.M. )

    1993-04-01

    Saturation conditions were measured for decane + octacosane, decane + p-xylene + octacosane, and decane + p-xylene + phenanthrene mixtures for approximately 10 mol % solid content and pressures up to 20 MPa. The solubility of octacosane in decane decreased by 43% at 312.4 K as the pressure increased from atmospheric to 20 MPa. The effect of pressure on phenanthrene solubility was much less.

  3. Metabolism of a representative oxygenated polycyclic aromatic hydrocarbon (PAH) phenanthrene-9,10-quinone in human hepatoma (HepG2) cells.

    PubMed

    Huang, Meng; Zhang, Li; Mesaros, Clementina; Zhang, Suhong; Blaha, Michael A; Blair, Ian A; Penning, Trevor M

    2014-05-19

    Exposure to polycyclic aromatic hydrocarbons (PAHs) in the food chain is the major human health hazard associated with the Deepwater Horizon oil spill. Phenanthrene is a representative PAH present in crude oil, and it undergoes biological transformation, photooxidation, and chemical oxidation to produce its signature oxygenated derivative, phenanthrene-9,10-quinone. We report the downstream metabolic fate of phenanthrene-9,10-quinone in HepG2 cells. The structures of the metabolites were identified by HPLC-UV-fluorescence detection and LC-MS/MS. O-mono-Glucuronosyl-phenanthrene-9,10-catechol was identified, as reported previously. A novel bis-conjugate, O-mono-methyl-O-mono-sulfonated-phenanthrene-9,10-catechol, was discovered for the first time, and evidence for both of its precursor mono conjugates was obtained. The identities of these four metabolites were unequivocally validated by comparison to authentic enzymatically synthesized standards. Evidence was also obtained for a minor metabolic pathway of phenanthrene-9,10-quinone involving bis-hydroxylation followed by O-mono-sulfonation. The identification of 9,10-catechol conjugates supports metabolic detoxification of phenanthrene-9,10-quinone through interception of redox cycling by UGT, COMT, and SULT isozymes and indicates the possible use of phenanthrene-9,10-catechol conjugates as biomarkers of human exposure to oxygenated PAH.

  4. Recovery of Phenanthrene-Degrading Bacteria After Simulated In Situ Persulfate Oxidation in Contaminated Soil

    PubMed Central

    Richardson, Stephen D.; Lebron, Benjamin L.; Miller, Cass T.; Aitken, Michael D.

    2010-01-01

    A continuous-flow column study was conducted to investigate the long-term effects of persulfate oxidation on the abundance and activity of the indigenous microbial community and phenanthrene-degrading bacteria in contaminated soil from a former manufactured gas plant (MGP) site. Approximately six pore volumes of a 20 g/L persulfate solution were introduced into the column, followed by simulated groundwater for 500 d. Soil samples were collected from the surface of the soil bed and along the column length immediately before and after persulfate injection and up to 500 d following injection. Exposure to persulfate led to a two- to three-log reduction in total bacterial 16S rRNA genes, severe inhibition of 14C-acetate mineralization (as a measure of general microbial activity), and a decrease in community diversity. However, relatively rapid recovery of both bacterial gene abundance and activity was observed within 30 d after persulfate exposure. Mineralization of 14C-phenanthrene was also inhibited but did not recover until 100 d post-oxidation. Known phenanthrene-degrading bacterial groups decreased to below detection limits throughout the column, with recovery times from 100 d to 500 d after persulfate injection. These findings suggest that coupling biological processes with persulfate oxidation is possible, although recovery of specific contaminant degraders may occur much later than the general microbial community recovers. Furthermore, the use of total bacterial quantity or non-specific measures of activity as a surrogate for the recovery of contaminant degraders may be inappropriate for evaluating the compatibility of chemical treatment with subsequent bioremediation. PMID:21162560

  5. Catalytic synthesis of high-value chemicals from coal-derived liquids. Conversion of phenanthrene derivatives into anthracene derivatives

    SciTech Connect

    Song, C.; Lai, W.C.

    1998-12-31

    It is known that phenanthrene and its derivatives are abundant in coal-derived liquids from coal carbonization, pyrolysis, and liquefaction; however, they have found little use in industry. On the other hand, anthracene and its derivatives are more useful materials for industrial applications. Thus, it is highly desirable to convert phenanthrene derivatives to anthracene derivatives. The authors have found that some chemically modified mordenites and Y-zeolites can selectively promote the transformation of sym-octahydrophenanthrene (sym-OHP) into sym-octahydroanthracene (sym-OHA) at lower temperatures. In this work, the effects of zeolite catalysts and reaction conditions on the ring-shift isomerization of sym-OHP into sym-OHA were studied through experiments at 200--300 C under an initial pressure of 0.79 MPa N{sub 2} or H{sub 2}. They also explored the simultaneous hydrogenation-ring-shift isomerization of phenanthrene using zeolite-supported metal catalysts.

  6. Phenotypic and genotypic characterization of phenanthrene-degrading fluorescent Pseudomonas biovars

    SciTech Connect

    Johnsen, K.; Andersen, S.; Jacobsen, C.S.

    1996-10-01

    The genus Pseudomonas is a group of gram-negative motile rods know for large metabolic versatility as well as pathogenicity to plants, animals and humans. A large number of bacteria from this group capable of degrading polycyclic aromatic hydrocarbons have been isolated in soils and aquifers, but the identification is often conducted only to the Pseudomonas sp. level. This study aims to characterize a group of bacteria from the fluorescent Pseudomonas group degrading phenanthrene by four different methods to assess the bacterial diversity of the closely related group. 37 refs., 3 figs., 1 tab.

  7. Accumulation and elimination of (9-/sup 14/C)phenanthrene in the calico clam (Macrocallista maculata)

    SciTech Connect

    Solbakken, J.E.; Jeffrey, F.M.H.; Knap, A.H.; Palmork, K.H.

    1982-05-01

    The accumulation and elimination of radoactivity is studied after exposure of (9-/sup 14/C) phenanthrene in various tissues in the calico clam (Macrocallista maculata). Results show that accumulation is highest in the lipid-rich hepatopancreas, and the elimination is very efficient compared to the horse mussel. The calico clam, which is a sand-dwelling organism, can easily come in contact with hydrocarbon contaminated sedments and might accumulate the hydrocarbons at different extents in various tissues. The efficient elimination, however, will prevent a lasting accumulation. (JMT)

  8. Disposition of phenanthrene and octachlorostyrene in spiny lobsters, Panulirus argus, after intragastric administration

    SciTech Connect

    Solbakken, J.E.; Knap, A.H.

    1986-11-01

    Spiny lobster (Panulirus argus) is a commercial crustacean in Bermuda. It was therefore of interest to study the fate of xenobiotics in the species as very little attention has been paid to toxicological studies with spiny lobsters. Earlier it was found that the temperate crustacean, Nephrops norveqicus (Norway lobster) had the ability to accumulate and eliminate phenanthrene. The aim of this investigation was to gain a better understanding of the fate of xenobiotics in crustaceans under different environmental conditions, and to compare the polycyclic aromatic hydrocarbon, phenenthrene, with the more environmentally persistent chlorinated compound octachlorostyrene, a by-product of magnesium metal production.

  9. Effects of humic acid on recoverability and fractal structure of alum-kaolin flocs.

    PubMed

    Zhong, Runsheng; Zhang, Xihui; Xiao, Feng; Li, Xiaoyan

    2011-01-01

    Particle surface characteristics, floc recoverability and fractal structure of alum-kaolin flocs were investigated using in situ particle image velocimetry (PIV) and microbalance with or without humic acid. Experimental results indicated that the zeta potential of kaolin particle surface after adsorption of humic acid was related with humic acid concentration and its acid-base buffering capacity. Adsorption of humic acid resulted in more negative electrophoresis on the particle surface. Coagulant dosages for particles to form flocs would increase with increasing humic concentration. PIV was used to evaluate floc structural fragmentation, floc surface erosion as well as recoverability after high shear. It was found that the floc size during the steady phase of growth was small, while the regrowing capability decreased in the presence of humic acid. The recoverability was closely related with floc breakage modes including floc structural fragmentation and floc surface erosion. The fractal dimensions of alum-kaolin flocs by mass-size method based on microbalance would decrease with increasing humic concentration. This study proved that humic acid had adverse influences on the performance of coagulation process.

  10. EFFECT OF HUMIC ACID ON UPTAKE AND TRANSFER OF COPPER FROM MICROBES TO CILIATES TO COPEPODS

    EPA Science Inventory

    This research is part of an ongoing project designed to determine the effect of humic acid on the uptake and transfer of metals by marine organisms at the lower end of the food chain. Binding affinities for Cu, Cd, Zn, and Cr to Suwannee River humic acid were determined at variou...

  11. EFFECTS OF ALUMINUM-INDUCED AGGREGATION ON THE FLUORESCENCE OF HUMIC SUBSTANCES. (R822251)

    EPA Science Inventory

    Aluminum-induced aggregates of terrestrial and aquatic humic acid standards from the International Humic Substances Society are shown to be fluorescent by means of a multiwavelength fluorescence anisotropy experiment in which the data was treated with a model for nonspherical ...

  12. Humic Materials Offer Photoprotective Effect to Escherichia coli Exposed to Damaging Luminous Radiation.

    PubMed

    Muela, A.; García-Bringas, J.M.; Arana, I.; Barcina, I.

    2000-12-01

    The behavior of Escherichia coli immersed in aqueous systems amended with humic acids, under PAR, UV-A, UV-B, and simulated solar radiation was examined. Culturability, ability to elongate, functioning of the electron transport systems, and glucose uptake were assessed. Humic substances in the range from 1 to 50 mg L-1 protected cells from photoinactivation. Decrease in culturability and cellular activities was significantly (p <0.05) less in the presence of humic material. However, humic acids were not used as nutrients. Neither irradiated nor nonirradiated humic solutions (50 mg L-1) supported the growth of 105 cells ml-1. However, humic acids dissolved in 0.9% NaC1 efficiently absorbed light over wavelengths from 270 to 500 nm. Also, a photoprotective effect against simulated sunlight was observed when humic acids were not in contact with but rather enveloped the cellular suspensions in double-wall microcosms. The protection afforded by humic acids against luminous radiation likely derives from their ability to absorb these radiations and hence reduces the amount of energy reaching the cells.

  13. Capillary Electrophoresis and Fluorescence Excitation-Emission Matrix Spectroscopy for Characterization of Humic Substances

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Capillary electrophoresis (CE) and fluorescence spectroscopy have been used in natural organic matter (NOM) studies. In this study, we characterized five fulvic acids, six humic acids and two unprocessed NOM samples obtained from the International Humic Substances Society (IHSS) using these two ana...

  14. Structural and functional comparison of mobile and recalcitrant humic fractions from agricultural soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mobile humic acid (MHA) and calcium humate (CaHA) are humic fractions sequentially extracted from soil samples. MHA is extracted by dilute NaOH, and CaHA is subsequently extracted by dilute NaOH from the dilute HCl-washed soil residues of the first extraction. This chapter reviews the recent advance...

  15. CHARACTERIZATION OF HUMIC ACID SIZE FRACTIONS BY SEC AND MALS (R822832)

    EPA Science Inventory

    Latahco silt-loam humic acid was separated on a preparatory scale by size exclusion chromatography (SEC) on a gravity-fed Sepharose column. Four fractions from this separation were collected and further analyzed, along with whole humic acid, by high-performance SEC coupled with a...

  16. Distinguishing Black Carbon from Biogenic Humic Substances in Soil Clay Fractions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Most models of soil humic substances include a substantial component of aromatic carbon (C) either as the backbone of humic heteropolymers or as a significant component of supramolecular aggregates of degraded biopolymers. Here we report that most of the aromatic C in the clay fraction of three stud...

  17. Field trials of Growmate humic products in Central and South America: benefits of networked sites.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effectiveness of humic products as crop and soil amendments deserves further study but remains in dispute. Broad-based evidence for their performance could be gained through coordinated networks of sites that evaluate humic products under diverse soil and weather conditions and for several crop...

  18. Activators of Biochemical and Physiological Processes in Plants Based on Fine Humic Acids

    NASA Astrophysics Data System (ADS)

    Churilov, G.; Polishuk, S.; Kutskir, M.; Churilov, D.; Borychev, S.

    2015-11-01

    This article describes the application of ultrafine humic acids as growth promoters and development of crops, for example corn. During the study we determined the optimal concentration of humic acids in ultrafine state for presowing treatment of seeds of maize. An analysis of laboratory and field tests was presented. We showed the relationship between physiological changes and biochemical processes.

  19. Field Evaluations of Commercial Humic Products: Current Knowledge and Future Needs.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Humic products are extracts of lignite or leonardite, which are immature coals. Humic products are sold commercially; their advertisements claim they will improve plant growth when applied to plants or soil. They are bought by small proportions of row crop farmers and growers of flowers, vegetables,...

  20. Reduction and Reoxidation of Humic Acid: Influence on Spectroscopic Properties and Proton Binding

    SciTech Connect

    Maurer, F.; Christl, I; Kretzschmar, R

    2010-01-01

    Previous studies on proton and metal binding to humic substances have not considered a potential influence of reduction and oxidation of functional groups. Therefore, we investigated how proton binding of a purified soil humic acid was affected by reduction. Reduction of the humic acid was carried out using an electrochemical cell that allowed us to measure the amounts of electrons and protons involved in reduction reactions. We further applied spectroscopic methods (UV-vis, fluorescence, FT-IR, C-1s NEXAFS) to detect possible chemical changes in the humic acid induced by reduction and reoxidation. The effect of reduction on proton binding was determined with acid-base titrations in the pH range 4-10 under controlled redox conditions. During reduction, 0.54 mol kg{sup -1} protons and 0.55 mol kg{sup -1} electrons were transferred to humic acid. NICA-Donnan modeling revealed an equivalent increase in proton-reactive sites (0.52 mol kg{sup -1}) in the alkaline pH-range. Our results indicate that reduction of humic acid increased the amount of proton-reactive sites by 15% compared to the untreated state. Spectroscopic differences between the untreated and reduced humic acid were minor, apart from a lower UV-vis absorption of the reduced humic acid between 400 and 700 nm.

  1. Effects of advanced oxidation pretreatment on residual aluminum control in high humic acid water purification.

    PubMed

    Wang, Wendong; Li, Hua; Ding, Zhenzhen; Wang, Xiaochang

    2011-01-01

    Due to the formation of disinfection by-products and high concentrations of Al residue in drinking water purification, humic substances are a major component of organic matter in natural waters and have therefore received a great deal of attention in recent years. We investigated the effects of advanced oxidation pretreatment methods usually applied for removing dissolved organic matters on residual Al control. Results showed that the presence of humic acid increased residual Al concentration notably. With 15 mg/L of humic acid in raw water, the concentrations of soluble aluminum and total aluminum in the treated water were close to the quantity of Al addition. After increasing coagulant dosage from 12 to 120 mg/L, the total-Al in the treated water was controlled to below 0.2 mg/L. Purification systems with ozonation, chlorination, or potassium permanganate oxidation pretreatment units had little effects on residual Al control; while UV radiation decreased Al concentration notably. Combined with ozonation, the effects of UV radiation were enhanced. Optimal dosages were 0.5 mg O3/mg C and 3 hr for raw water with 15 mg/L of humic acid. Under UV light radiation, the combined forces or bonds that existed among humic acid molecules were destroyed; adsorption sites increased positively with radiation time, which promoted adsorption of humic acid onto polymeric aluminum and Al(OH)3(s). This work provides a new solution for humic acid coagulation and residual Al control for raw water with humic acid purification.

  2. Preparation of waxes and humic acids from brown coal from the Sergeevskoe deposit

    SciTech Connect

    L.P. Noskova; A.V. Rokhin; A.P. Sorokin

    2007-06-15

    The comparative extraction of coal with organic solvents was performed. Humic acids were separated from solid residues. The yields, particle-size distributions, and chemical compositions of the resulting products were analyzed. It was demonstrated that brown-coal wax and humic fertilizers can potentially be obtained using coal from the Sergeevskoe deposit.

  3. Biodegradability of nonaqueous-phase liquids affects the mineralization of phenanthrene in soil because of microbial competition

    SciTech Connect

    Morrison, D.E.; Alexander, M.

    1997-08-01

    A study was conducted to determine the effects of biodegradability of nonaqueous-phase liquids (NAPLs) and microbial competition on the biodegradation in soil of a constituent of the NAPLs. The rates of mineralization of phenanthrene dissolved in 8 mg of 2,2,4,4,6,8,8-heptamethylnonane (HMN), di(2-ethylhexyl) phthalate (DEHP), or pristane per g of soil were faster than the rates when the compound was dissolved in hexadecane or dodecane. Addition of inorganic N and P to the soil increased the mineralization rate in the first two but not the last two NAPLs. N and P addition did not enhance mineralization of phenanthrene when added in 500 {micro}g of hexadecane, pristane, or HMN per g of soil. Hexadecane was rapidly degraded, pristane was slowly metabolized, DEHP was still slower, and HMN was not mineralized in the test period. Mixing the soil stimulated mineralization of phenanthrene dissolved in HMN but not in hexadecane. Mineralization of phenanthrene dissolved in HMN was the same if the gas phase contained 21%, 2.1%, or traces of O{sub 2}. In contrast, the biodegradation of phenanthrene dissolved in hexadecane, although the same at 21 and 2.1% O{sub 2}, was not observed if traces of O{sub 2} were present. The mineralization was slower in unshaken soil-water mixtures if phenanthrene was added in hexadecane than in HMN or pristane, but the rates with the 3 NAPLs were increased by shaking the suspensions. The authors suggest that the biodegradability of major components of NAPLs and microbial competition for N, P, or O{sub 2} will have a major impact on the rate of transformation of minor constituents of NAPLs.

  4. Beneficial effects of humic acid on micronutrient availability to wheat

    NASA Technical Reports Server (NTRS)

    Mackowiak, C. L.; Grossl, P. R.; Bugbee, B. G.

    2001-01-01

    Humic acid (HA) is a relatively stable product of organic matter decomposition and thus accumulates in environmental systems. Humic acid might benefit plant growth by chelating unavailable nutrients and buffering pH. We examined the effect of HA on growth and micronutrient uptake in wheat (Triticum aestivum L.) grown hydroponically. Four root-zone treatments were compared: (i) 25 micromoles synthetic chelate N-(4-hydroxyethyl)ethylenediaminetriacetic acid (C10H18N2O7) (HEDTA at 0.25 mM C); (ii) 25 micromoles synthetic chelate with 4-morpholineethanesulfonic acid (C6H13N4S) (MES at 5 mM C) pH buffer; (iii) HA at 1 mM C without synthetic chelate or buffer; and (iv) no synthetic chelate or buffer. Ample inorganic Fe (35 micromoles Fe3+) was supplied in all treatments. There was no statistically significant difference in total biomass or seed yield among treatments, but HA was effective at ameliorating the leaf interveinal chlorosis that occurred during early growth of the nonchelated treatment. Leaf-tissue Cu and Zn concentrations were lower in the HEDTA treatment relative to no chelate (NC), indicating HEDTA strongly complexed these nutrients, thus reducing their free ion activities and hence, bioavailability. Humic acid did not complex Zn as strongly and chemical equilibrium modeling supported these results. Titration tests indicated that HA was not an effective pH buffer at 1 mM C, and higher levels resulted in HA-Ca and HA-Mg flocculation in the nutrient solution.

  5. Capillary electrophoretic separation of humic substances using hydroxyethyl cellulose as a buffer additive and its application to characterization of humic substances in a river water sample.

    PubMed

    Takahashi, Toru; Kawana, Jun; Hoshino, Hitoshi

    2009-01-01

    We have developed a concise tool for the investigation of the transition of humic substances in environmental water. The separation of water-soluble humic substances was achieved rapidly and effectively by capillary electrophoresis using a polyacrylamide-coated capillary and a phosphate electrophoretic buffer solution (pH 7.0) containing hydroxyethyl cellulose. The separation mechanism was assessed using the ultrafiltration technique. The effect of the complexation of humic substances with metal ions was studied by using the proposed method. When Fe(III) ions or EDTA was added to the sample solution of fulvic acid, a distinct change in the electropherogram pattern based on the conformational change of fulvic acid was observed. The successful application of the proposed method to the characterization of humic substances in a river water sample was also demonstrated.

  6. Analysis of carbon functional groups in mobile humic acid and recalcitrant calcium humate extracted from eight US soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Solid state 13C nuclear magnetic resonance (NMR) spectroscopy is a common tool to study the structure of soil humic fractions; however, knowledge regarding carbon structural relationships in humic fractions is limited. In this study, mobile humic acid (MHA) and recalcitrant calcium humate (CaHA) fr...

  7. Usage of humic materials for formulation of stable microbial inoculants

    NASA Astrophysics Data System (ADS)

    Kydralieva, K. A.; Khudaibergenova, B. M.; Elchin, A. A.; Gorbunova, N. V.; Muratov, V. S.; Jorobekova, Sh. J.

    2009-04-01

    Some microbes have been domesticated for environment service, for example in a variety of novel applications, including efforts to reduce environmental problems. For instance, antagonistic organisms can be used as biological control agents to reduce the use of chemical pesticides, or efficient degraders can be applied as bioprophylactics to minimise the spread of chemical pollutants. Microorganisms can also be used for the biological clean-up of polluted soil or as plant growth-promoting bacteria that stimulate nutrient uptake. Many microbial applications require large-scale cultivation of the organisms. The biomass production must then be followed by formulation steps to ensure long-term stability and convenient use. However, there remains a need to further develop knowledge on how to optimise fermentation of "non-conventional microorganisms" for environmental applications involving the intact living cells. The goal of presented study is to develop fermentation and formulation techniques for termolabile rhizobacteria isolates - Pseudomonas spp. with major biotechnical potential. Development of efficient and cost-effective media and process parameters giving high cell yields are important priorities. This also involves establishing fermentation parameters yielding cells well adapted to subsequent formulation procedures. Collectively, these strategies will deliver a high proportion of viable cells with good long-term survival. Our main efforts were focused on development of more efficient drying techniques for microorganisms, particularly spray drying and fluidised bed-drying. The advantages of dry formulations are that storage and delivery costs are much lower than for liquid formulations and that long-term survival can be very high if initial packaging is carefully optimised. In order to improve and optimise formulations various kinds of humics-based excipients have been added that have beneficial effects on the viability of the organisms and the storage stability

  8. Humic colloid-borne natural polyvalent metal ions: dissociation experiment.

    PubMed

    Geckeis, H; Rabung, Th; Ngo Manh, T; Kim, J I; Beck, H P

    2002-07-01

    The natural association nature of the humic colloid-borne trace elements is investigated. Rare earth elements (REE) Th and U are chosen as naturally occurring representatives and chemical homologues for actinides of different oxidation states present in nuclear waste. Tri- and tetravalent elements in two investigated Gorleben groundwaters (Gohy-532 and -2227) almost exclusively occur as humic or fulvic colloid-borne species. Their desorption behavior from colloids is examined in the unperturbed groundwater (pH approximately 8) under anaerobic conditions (Ar/1% CO2) by addition of a chelating cation exchanger resin. Particularly, the dissociation process of naturally occurring Eu(III) in the groundwater is compared with the Eu(III) desorption from its humate complex prepared with purified Aldrich humic acid in a buffered aqueous solution at pH approximately 8. The Eu(III) dissociation from the groundwater colloids is found to be considerably slower than found for the humate complex synthesized in the laboratory. This suggests that under natural aquatic conditions the Eu(III) binding in colloids is chemically different from the simple humate complexation as observed in the laboratory experiment. The colloid characterization bythe size exclusion chromatography (SEC) and the flow field-flow fractionation (FFFF) indicates that natural colloid-borne trace elements are found predominantly in colloids of larger size (>15 nm in size), while Eu(III) in its humate complex is found mainly in colloids of hydrodynamic diameters <5 nm. The slower desorption kinetics and the larger colloid size suggest that the polyvalent metal ion binding in natural humic colloids is associated to polynucleation with other co-present trace metal ions. Radiotracer experiments reveal that isotopic equilibria with the naturally colloid-borne trace elements are not attained within a period of more than 100 days, indicating irreversible binding of at least a part of colloid-borne polyvalent trace

  9. Electrochemical reduction of oxygen in the presence of humic acids

    NASA Astrophysics Data System (ADS)

    Mal'Tseva, E. V.; Yudina, N. V.; Lomovskii, O. I.

    2011-07-01

    The effect of the nature of humic acids (HAs), their modification by mechanochemical methods, and the pH of the medium on the electrochemical reduction of oxygen is determined. The mechanical activation of caustobioliths, regardless of their nature, is shown to increase the role of quinone moieties in the composition of HAs, thus promoting the initiation of the electrochemical reduction of O2 in a basic medium. The conclusion is drawn that this changes not only the ratio of redox-active moieties in HAs, which determine the total antioxidant activity, but also their character.

  10. Modeling lanthanide series binding sites on humic acid.

    PubMed

    Pourret, Olivier; Martinez, Raul E

    2009-02-01

    Lanthanide (Ln) binding to humic acid (HA) has been investigated by combining ultrafiltration and ICP-MS techniques. A Langmuir-sorption-isotherm metal-complexation model was used in conjunction with a linear programming method (LPM) to fit experimental data representing various experimental conditions both in HA/Ln ratio (varying between 5 and 20) and in pH range (from 2 to 10) with an ionic strength of 10(-3) mol L(-1). The LPM approach, not requiring prior knowledge of surface complexation parameters, was used to solve the existing discrepancies in LnHA binding constants and site densities. The application of the LPM to experimental data revealed the presence of two discrete metal binding sites at low humic acid concentrations (5 mg L(-1)), with log metal complexation constants (logK(S,j)) of 2.65+/-0.05 and 7.00 (depending on Ln). The corresponding site densities were 2.71+/-0.57x10(-8) and 0.58+/-0.32x10(-8) mol of Ln(3+)/mg of HA (depending on Ln). Total site densities of 3.28+/-0.28x10(-8), 4.99+/-0.02x10(-8), and 5.01+/-0.01x10(-8) mol mg(-1) were obtained by LPM for humic acid, for humic acid concentrations of 5, 10, and 20 mg L(-1), respectively. These results confirm that lanthanide binding occurs mainly at weak sites (i.e., ca. 80%) and second at strong sites (i.e., ca. 20%). The first group of discrete metal binding sites may be attributed to carboxylic groups (known to be the main binding sites of Ln in HA), and the second metal binding group to phenolic moieties. Moreover, this study evidences heterogeneity in the distribution of the binding sites among Ln. Eventually, the LPM approach produced feasible and reasonable results, but it was less sensitive to error and did not require an a priori assumption of the number and concentration of binding sites.

  11. Humic acid toxicity in biologically treated soil contaminated with polycyclic aromatic hydrocarbons and pentachlorophenol.

    PubMed

    Nieman, J K C; Sims, R C; Sorensen, D L; McLean, J E

    2005-10-01

    Contaminated soil from a land treatment unit at the Libby Groundwater Superfund Site in Libby, MT, was amended with 14C pyrene and incubated for 396 days to promote biodegradation and the formation of soil-associated bound residues. Humic and fulvic acids were extracted from the treated soil microcosms and analyzed for the presence of pyrene residues. Biologic activity promoted 14C association with the fulvic acid fraction, but humic acid-associated 14C did not increase with biologic activity. The Aboatox flash toxicity assay was used to assess the toxicity of humic and fulvic acid fractions. The fulvic acid gave no toxic response, but the humic acid showed significant toxicity. The observed toxicity was likely associated with pentachlorophenol, a known contaminant of the soil that was removed by solvent extraction of the humic acid and that correlated well with toxicity reduction.

  12. NMR characterization and sorption behavior of agricultural and forest soil humic substances

    NASA Astrophysics Data System (ADS)

    Li, Chengliang; Berns, Anne E.; Séquaris, Jean-Marie; Klumpp, Erwin

    2010-05-01

    Humic substances are the predominant components of the organic matter in the terrestrial system, which are not only important for the physicochemical properties of soil but are also dominant factors for controlling the environmental behaviors and fates of some organic contaminants, such as hydrophobic compounds. Nonylphenol [4-(1-ethyl-1, 3 dimethylpentyl) phenol] (NP), a ubiquitous hydrophobic pollutant, has recently focused the attention owing to its endocrine disruptors property. Sorption behavior of NP on humic substances, which were isolated from agricultural and forest soils, was investigated by using the dialysis technique at room temperature. 14C-labeled NP was used to quantify the partitioning behavior. Humic substances were characterized by 13C Cross-Polarization/Magic-Angle-Spinning Nuclear Magnetic Resonance (CP/MAS NMR). The results showed that the partition parameters of NP on various humic acids were slightly different. Relationships between partition coefficients and the functional groups of humic substances identified by CP/MAS NMR were analyzed.

  13. Dietary taurine supplementation ameliorates the lethal effect of phenanthrene but not the bioaccumulation in a marine teleost, red sea bream, Pagrus major.

    PubMed

    Hano, Takeshi; Ito, Mana; Ito, Katsutoshi; Kono, Kumiko; Ohkubo, Nobuyuki

    2017-03-01

    The present study was performed to evaluate the effect of dietary taurine on the hepatic metabolic profiles of red sea bream (Pagrus major) and on phenanthrene (a polyaromatic hydrocarbon) toxicity and bioaccumulation. The fish were fed a diet supplemented with 0% (TAU0%), 0.5% (TAU0.5%), or 5% (TAU5%) taurine for 40-55d and subjected to phenanthrene acute toxicity and bioaccumulation tests. Taurine deficiency in feed severely affected the hepatic metabolic profiles of fish, which indicated a complementary physiological response to taurine deficiency. For the acute toxicity test, fish were fed the test diets for 55d and were then exposed to 0-893µg/L phenanthrene for 96h. Tolerance to phenanthrene was significantly improved by 0.5% of taurine inclusion in feed relative to TAU0%, but not by 5.0% inclusion. Reduced glutathione in the liver, which acts as an oxygen-free radical scavenger, was associated with a reduction in the toxicity of phenanthrene. For the bioaccumulation test, fish were fed the test diets for 40d and were thereafter chronically exposed to 20µg/L phenanthrene for 13d followed by depuration for 3d. The activity of hepatic biomarker, ethoxyresorufin-O-deethylase, was increased by phenanthrene exposure in the taurine inclusion groups. However, phenanthrene concentrations in the liver and muscle of fish fed TAU5.0% tended to be higher than those of fish fed TAU0% and TAU0.5% during the exposure period. These results indicate that 0.5% of taurine inclusion in feed plays an important role in the alleviation of phenanthrene toxicity but not bioaccumulation. Furthermore, larger amount of taurine inclusion (TAU5%) did not show marked beneficial effects against phenanthrene exposure. This study provides insight about a major concern of environmental contaminants into aquatic environment and can be effectively used for improvement of aquaculture.

  14. Inhibition of humic substances mediated photooxygenation of furfuryl alcohol by 2,4,6-trimethylphenol. Evidence for reactivity of the phenol with humic triplet excited states.

    PubMed

    Halladja, Sabrina; Ter Halle, Alexandra; Aguer, Jean-Pierre; Boulkamh, Abdelaziz; Richard, Claire

    2007-09-01

    To probe the reactivity of 2,4,6-trimethylphenol with humic triplet excited states, we investigated its influence on the humic substances-mediated photooxygenation offurfuryl alcohol. Elliott soil humic and fulvic acids were employed for these experiments. When added in the concentration range of 10(-4) - 10(-3) M, 2,4,6-trimethylphenol inhibited furfuryl alcohol photooxygenation to an extent depending on its concentration. The inhibiting effect decreased as the oxygen concentration was increased. By postulating that 2,4,6-trimethylphenol competes with oxygen for reaction with humic triplet excited states and with furfuryl alcohol for reaction with singlet oxygen, we obtained kinetic laws describing the consumption profiles of furfuryl alcohol and 2,4,6-trimethylphenol. Experimental rates of 2,4,6-trimethylphenol and furfuryl alcohol loss could be satisfactorily fitted with 1.09-1.16 for the ratio k2/k3, where k2 and k3 are the reaction rate constants of humic triplet excited states with oxygen and 2,4,6-trimethylphenol, respectively. These types of experiments could be extended to a variety of substrates to measure their reaction rate constants with humic triplet excited states.

  15. An experimental and modeling study of humic acid concentration effect on H(+) binding: Application of the NICA-Donnan model.

    PubMed

    Vidali, Roza; Remoundaki, Emmanouela; Tsezos, Marios

    2009-11-15

    Humic substances are the most abundant components of the colloidal and the dissolved fraction of natural organic matter (NOM) and they are characterized by a strong binding capacity for both metals and organic pollutants, affecting their mobility and bioavailability. The understanding of the humic acidic character is the first necessary step for the study of the mechanisms of binding of other positively charged soluble metal species by humic molecules. The present work, which constitutes part of the Ph.D. thesis of Roza Vidali, reports results on the influence of the concentration of humic acids on the binding of protons obtained through both an experimental and a modeling approach. A reference purified peat humic acid (PPHA) isolated by the International Humic Substances Society (IHSS) and a humic acid from a Greek soil (GHA) were experimentally studied at various humic acid concentrations, ranging from 20 to 200mgL(-1). The proton binding isotherms obtained at different humic acid concentrations have shown that proton binding is dependent on the concentration of both humic acids. Proton binding experimental data were fitted to the NICA-Donnan model and the model parameter values were calculated for humic acid concentrations of 20 and >or=100mgL(-1). The results obtained for the NICA-Donnan parameters at humic acid concentrations >or=100mgL(-1) are in excellent agreement with those reported in the literature. However, these model parameter values cannot be used for modeling and predicting cation binding in natural aquatic systems, where humic acid concentrations are much lower. Two sets of the NICA-Donnan parameters are reported: one for humic acid concentrations of >or=100mgL(-1) and one for humic acid concentration of 20mgL(-1). The significance of the parameters values for each concentration level is also discussed.

  16. Properties of the low-lying electronic states of phenanthrene: Exact PPP results

    SciTech Connect

    Chakrabarti, A.; Ramasesha, S.

    1996-10-05

    The authors report properties of the exact low-lying states of phenanthrene, its anion and dianion within the Pariser-Parr-Pople (PPP) model. The experimentally known singlet states of the neutral molecule are well reproduced by the model. The intensities for one and two photon absorption to various single states are also in good agreement with experiment. From the bond orders of these states, the authors predict the equilibrium geometries. The relaxation energies of these states, computed from charge-charge correlations and bond orders, are presented. The authors also present results of ring current calculations in the singlet ground state of phenanthrene. The authors have also reported energies, spin densities, bond orders, and relaxation energies of several triplet states and compared then with experiments as well as with other calculations, where available. The fine structure constants D and E, computed in the lowest triplet state, compare well with those obtained from experiments. These properties are also presented for the anions and the dianions. The PPP model in these cases predicts a low-energy (< 1 eV) dipole excitation. 31 refs., 4 figs., 9 tabs.

  17. Impacts of heterogeneous organic matter on phenanthrene sorption--Different soil and sediment samples

    USGS Publications Warehouse

    Karapanagioti, Hrissi K.; Childs, Jeffrey; Sabatini, David A.

    2001-01-01

    Organic petrography has been proposed as a tool for characterizing the heterogeneous organic matter present in soil and sediment samples. A new simplified method is proposed as a quantitative means of interpreting observed sorption behavior for phenanthrene and different soils and sediments based on their organic petrographical characterization. This method is tested under singe solute conditions and at phenanthrene concentration of 1 μg/L. Since the opaque organic matter fraction dominates the sorption process, we propose that by quantifying this fraction one can interpret organic content normalized sorption distribution coefficient (Koc) values for a sample. While this method was developed and tested for various samples within the same aquifer, in the current study the method is validated for soil and sediment samples from different sites that cover a wide range of organic matter origin, age, and organic content. All 10 soil and sediment samples studied had log Koc values for the opaque particles between 5.6 and 6.8. This range of Koc values illustrates the heterogeneity of opaque particles between sites and geological formations and thus the need to characterize the opaque fraction of materials on a site-by-site basis.

  18. The effect of soil: water ratios on the mineralisation of phenanthrene: LNAPL mixtures in soil.

    PubMed

    Doick, Kieron J; Semple, Kirk T

    2003-03-14

    Contamination of soil by polycyclic aromatic hydrocarbons is frequently associated with non-aqueous-phase liquids. Measurement of the catabolic potential of a soil or determination of the biodegradable fraction of a contaminant can be done using a slurried soil respirometric system. This work assessed the impact of increasing the concentration of transformer oil and soil:water ratio on the microbial catabolism of [(14)C]phenanthrene to (14)CO(2) by a phenanthrene-degrading inoculum. Slurrying (1:1, 1:2, 1:3 and 1:5 soil:water ratios) consistently resulted in statistically higher rates and extents of mineralisation than the non-slurried system (2:1 soil:water ratio; P<0.01). The maximum extents of mineralisation observed occurred in the 1:2-1:5 soil:water ratio microcosms irrespective of transformer oil concentration. Transformer oil concentrations investigated displayed no statistically significant effect on total mineralisation (P>0.05). Soil slurries 1:2 or greater, but less than 1:5 (soil:water), are recommended for bioassay determinations of total contaminant bioavailability due to greater overall mineralisation and improved reproducibility.

  19. Oxidative metabolism of phenanthrene and anthracene by soil pseudomonads. The ring-fission mechanism

    PubMed Central

    Evans, W. C.; Fernley, H. N.; Griffiths, E.

    1965-01-01

    1. Phenanthrene is oxidatively metabolized by soil pseudomonads through trans-3,4-dihydro-3,4-dihydroxyphenanthrene to 3,4-dihydroxyphenanthrene, which then undergoes cleavage. 2. Some properties of the ring-fission product, cis-4-(1-hydroxynaphth-2-yl)-2-oxobut-3-enoic acid, are described. The Fe2+-dependent oxygenase therefore disrupts the bond between C-4 and the angular C of the phenanthrene nucleus. 3. An enzyme of the aldolase type converts the fission product into 1-hydroxy-2-naphthaldehyde (2-formyl-1-hydroxynaphthalene). An NAD-specific dehydrogenase is also present in the cell-free extract, which oxidizes the aldehyde to 1-hydroxy-2-naphthoic acid. This is then oxidatively decarboxylated to 1,2-dihydroxynaphthalene, thus allowing continuation of metabolism via the naphthalene pathway. 4. Anthracene is similarly metabolized, through 1,2-dihydro-1,2-dihydroxyanthracene to 1,2-dihydroxyanthracene, in which ring-fission occurs to give cis-4-(2-hydroxynaphth-3-yl)-2-oxobut-3-enoic acid. The position of cleavage is again at the bond between the angular C and C-1 of the anthracene nucleus. 5. Enzymes that convert the fission product through 2-hydroxy-3-naphthaldehyde into 2-hydroxy-3-naphthoic acid were demonstrated. The further metabolism of this acid is discussed. 6. The Fe2+-dependent oxygenase responsible for cleavage of all the o-dihydroxyphenol derivatives appears to be catechol 2,3-oxygenase, and is a constitutive enzyme in the Pseudomonas strains used. PMID:14342521

  20. Flame-retardant EPDM compounds containing phenanthrene to enhance radiation resistance

    NASA Astrophysics Data System (ADS)

    Chen, Jian; Huang, Wei; Jiang, Shu-Bin; Li, Xiao-Yan; An, You; Li, Chuang; Gao, Xiao-Ling; Chen, Hong-Bing

    2017-01-01

    Ethylene propylene diene monomer (EPDM) compounds with good flame-retardant and γ-ray radiation resistant properties were prepared by adding complex flame retardants and phenathrene. The resultant EPDM formulations have a long time to ignition (TTI >46 s), a low peak heat release rate (PHRR 341 kW/m2) and a high limited oxygen index (LOI >30). Effects of γ-ray radiation on the resultant flame-retardant EPDM was investigated. The formulated EPDM is a crosslinking dominated polymer under γ-ray radiation. The γ-ray radiation resistant property of EPDM was enhanced by adding phenanthrene. Elongation at break of EPDM formulated with phenanthrene could retain 91% after being irradiated to 0.3 MGy and still retains 40% elongation even after being irradiated to 0.9 MGy, which is much better the control. It is expected that the formulated flame-retardant and radiation resistant EPDM materials could meet the requirements for use in radiation environments.

  1. Electrocoagulation treatment of peat bog drainage water containing humic substances.

    PubMed

    Kuokkanen, V; Kuokkanen, T; Rämö, J; Lassi, U

    2015-08-01

    Electrocoagulation (EC) treatment of 100 mg/L synthetic wastewater (SWW) containing humic acids was optimized (achieving 90% CODMn and 80% DOC removal efficiencies), after which real peat bog drainage waters (PBDWs) from three northern Finnish peat bogs were also treated. High pollutant removal efficiencies were achieved: Ptot, TS, and color could be removed completely, while Ntot, CODMn, and DOC/TOC removal efficiencies were in the range of 33-41%, 75-90%, and 62-75%, respectively. Al and Fe performed similarly as the anode material. Large scale experiments (1 m(3)) using cold (T = 10-11 °C) PBDWs were also conducted successfully, with optimal treatment times of 60-120 min (applying current densities of 60-75 A/m(2)). Residual values of Al and Fe (complete removal) were lower than their initial values in the EC-treated PBDWs. Electricity consumption and operational costs in optimum conditions were found to be low and similar for all the waters studied: 0.94 kWh/m(3) and 0.15 €/m(3) for SWW and 0.35-0.70 kWh/m(3) and 0.06-0.12 €/m(3) for the PBDWs (large-scale). Thus, e.g. solar cells could be considered as a power source for this EC application. In conclusion, EC treatment of PBDW containing humic substances was shown to be feasible.

  2. Natural carbon-based dots from humic substances

    NASA Astrophysics Data System (ADS)

    Dong, Yongqiang; Wan, Lisi; Cai, Jianhua; Fang, Qingqing; Chi, Yuwu; Chen, Guonan

    2015-05-01

    For the first time, abundant natural carbon-based dots were found and studied in humic substances (HS). Four soluble HS including three humic acids (HA) from different sources and one fulvic acids (FA) were synthetically studied. Investigation results indicate that all the four HS contain large quantities of Carbon-based dots. Carbon-based dots are mainly small-sized graphene oxide nano-sheets or oxygen-containing functional group-modified graphene nano-sheets with heights less than 1 nm and lateral sizes less than 100 nm. Carbon-based nanomaterials not only contain abundant sp2-clusters but also a large quantity of surface states, exhibiting unique optical and electric properties, such as excitation-dependent fluorescence, surface states-originated electrochemiluminescence, and strong electron paramagnetic resonance. Optical and electric properties of these natural carbon-based dots have no obvious relationship to their morphologies, but affected greatly by their surface states. Carbon-based dots in the three HS have relative high densities of surface states whereas the FA has the lowest density of surface states, resulting in their different fluorescence properties. The finding of carbon-based dots in HS provides us new insight into HS, and the unique optical properties of these natural carbon-based dots may give HS potential applications in areas such as bio-imaging, bio-medicine, sensing and optoelectronics.

  3. Cloud formation of particles containing humic-like substances

    NASA Astrophysics Data System (ADS)

    Kokkola, H.; Sorjamaa, R.; Peräniemi, A.; Raatikainen, T.; Laaksonen, A.

    2006-05-01

    Humic like substances (HULIS) are a class of compounds that are suspected to have an effect on cloud droplet activation properties of atmospheric aerosols because they decrease the surface tension of aqueous solutions quite efficiently. Surface active organic compounds have a tendency of concentrating on the surfaces of liquid droplets. If the total amount of surface active compound is small enough, partitioning of the substance on the surface depletes it from the droplet interior, decreasing the Raoult effect and increasing the Kelvin effect. Thus, the surface partitioning causes an increase of the critical supersaturation (Köhler curve maximum), and the effect gets stronger with decreasing size of the cloud condensation nucleus. In this study, the effects of HULIS on the activation of cloud droplets was studied by cloud parcel model calculations. Model results indicate that if the surface partitioning is not taken into account, the number of activated droplets can be highly overestimated. The simulations were made using particles containing 10-80% mass fraction of HULIS, while the remaining fraction of the particle was ammonium sulfate. The calculations indicated that the surface tension effects of humic-like compounds on the cloud activation become significant only when the weight fraction of the organics is very high. In contrast, if the surface partitioning is not taken into account, already a small weight fraction of organics will lead to significant increase in number of cloud droplets.

  4. Production of humic substances through coal-solubilizing bacteria

    PubMed Central

    Valero, Nelson; Gómez, Liliana; Pantoja, Manuel; Ramírez, Ramiro

    2014-01-01

    In this paper, the production of humic substances (HS) through the bacterial solubilization of low rank coal (LRC) was evaluated. The evaluation was carried out by 19 bacterial strains isolated in microenvironments with high contents of coal wastes. The biotransformed LRC and the HS produced were quantified in vitro in a liquid growth medium. The humic acids (HA) obtained from the most active bacterial strain were characterized via elemental composition (C, H, N, O), IR analyses, and the E4/E6 ratio; they were then compared with the HA extracted chemically using NaOH. There was LRC biotransformation ranged from 25 to 37%, and HS production ranged from 127 to 3100 mg.L−1. More activity was detected in the isolated strains of Bacillus mycoides, Microbacterium sp, Acinetobacter sp, and Enterobacter aerogenes. The HA produced by B. mycoides had an IR spectrum and an E4/E6 ratio similar to those of the HA extracted with NAOH, but their elemental composition and their degree of aromatic condensation was different. Results suggest that these bacteria can be used to exploit the LRC resulting from coal mining activities and thus produce HS in order to improve the content of humified organic matter in soils. PMID:25477925

  5. Properties and structure of raised bog peat humic acids

    NASA Astrophysics Data System (ADS)

    Klavins, Maris; Purmalis, Oskars

    2013-10-01

    Humic substances form most of the organic components of soil, peat and natural waters, and their structure and properties differ very much depending on their source. The aims of this study are to characterize humic acids (HAs) from raised bog peat, to evaluate the homogeneity of peat HAs within peat profiles, and to study peat humification impact on properties of HAs. A major impact on the structure of peat HAs have lignin-free raised bog biota (dominantly represented by bryophytes of different origin). On diagenesis scale, peat HAs have an intermediate position between the living organic matter and coal organic matter, and their structure is formed in a process in which more labile structures (carbohydrates, amino acids, etc.) are destroyed, while thermodynamically more stable aromatic and polyaromatic structures emerge as a result of abiotic synthesis. However, in comparison with soil, aquatic and other HAs, aromaticity of peat HAs is much lower. Comparatively, the raised bog peat HAs are at the beginning of the transformation process of living organic matter. Concentrations of carboxyl and phenolic hydroxyl groups change depending on the peat age and decomposition degree from where HAs have been isolated, and carboxylic acidity of peat HAs increases with peat depth and humification degree.

  6. Effects of outer membrane vesicle formation, surface-layer production and nanopod development on the metabolism of phenanthrene by Delftia acidovorans Cs1-4.

    PubMed

    Shetty, Ameesha; Hickey, William J

    2014-01-01

    Nanopods are extracellular structures arising from the convergence of two widely distributed bacterial characteristics: production of outer membrane vesicles (OMV) and formation of surface layers (S-layers). Nanopod production is driven by OMV formation, and in Delftia acidovorans Cs1-4 growth on phenanthrene induces OMV/nanopod formation. While OMV production has been associated with many functions, particularly with pathogens, linkage to biodegradation has been limited to a membrane stress response to lipophilic compounds. The objectives of this study were to determine: 1.) Whether induction of nanopod formation was linked to phenanthrene metabolism or a non-specific membrane stress response, and 2.) The relative importance of OMV/nanopod formation vs. formation of the S-layer alone to phenanthrene utilization. Membrane stress response was investigated by quantifying nanopod formation following exposure to compounds that exceeded phenanthrene in membrane stress-inducing potential. Naphthalene did not induce nanopod formation, and toluene was a weak inducer compared to phenanthrene (two- vs. six-fold increase, respectively). Induction of nanopod formation by growth on phenanthrene was therefore linked to phenanthrene metabolism and not a membrane stress response. Impacts on phenanthrene biodegradation of OMV/nanopod production vs. S-layer formation were assessed with D. acidovorans Cs1-4 mutants deficient in S-layer formation or OMV/nanopod production. Both mutants had impaired growth on phenanthrene, but the loss of OMV/nanopod production was more significant than loss of the S-layer. The S-layer of D. acidovorans Cs1-4 did not affect phenanthrene uptake, and its primary role in phenanthrene biodegradation process appeared to be enabling nanopod development. Nanopods appeared to benefit phenanthrene biodegradation by enhancing cellular retention of metabolites. Collectively, these studies established that nanopod/OMV formation was an essential characteristic of

  7. Use of solid-state 13C NMR in structural studies of humic acids and humin from Holocene sediments

    USGS Publications Warehouse

    Hatcher, P.G.; VanderHart, D.L.; Earl, W.L.

    1980-01-01

    13C NMR spectra of solid humic substances in Holocene sediments have been obtained using cross polarization with magic-angle sample spinning techniques. The results demonstrate that this technique holds great promise for structural characterizations of complex macromolecular substances such as humin and humic acids. Quantifiable distinctions can be made between structural features of aquatic and terrestrial humic substances. The aliphatic carbons of the humic substances are dominant components suggestive of input from lipid-like materials. An interesting resemblance is also noted between terrestrial humic acid and humin spectra. ?? 1980.

  8. Effects of peat fires on the characteristics of humic acid extracted from peat soil in Central Kalimantan, Indonesia.

    PubMed

    Yustiawati; Kihara, Yusuke; Sazawa, Kazuto; Kuramitz, Hideki; Kurasaki, Masaaki; Saito, Takeshi; Hosokawa, Toshiyuki; Syawal, M Suhaemi; Wulandari, Linda; Hendri I; Tanaka, Shunitz

    2015-02-01

    When peat forest fires happen, it leads to burn soil and also humic acids as a dominant organic matter contained in peat soil as well as the forest. The structure and properties of humic acids vary depending on their origin and environment, therefore the transformation of humic acid is also diverse. The impacts of the peat fires on peat soil from Central Kalimantan, Indonesia were investigated through the characterization of humic acids, extracted from soil in burnt and unburnt sites. The characterization of humic acids was performed by elemental composition, functional groups, molecular weight by HPSEC, pyrolysate compounds by pyrolysis-GC/MS, fluorescence spectrum by 3DEEM spectrofluorometer, and thermogravimetry. The elemental composition of each humic substance indicated that the value of H/C and O/C of humic acids from burnt sites were lower than that from unburnt sites. The molecular weight of humic acids from burnt sites was also lower than that from unburnt sites. Pyrolysate compounds of humic acids from unburnt sites differed from those of humic acids from burnt soil. The heating experiment showed that burning process caused the significant change in the properties of humic acids such as increasing the aromaticity and decreasing the molecular weight.

  9. Effects of Humic Acids Isolated from Peat of Various Origin on in Vitro Production of Nitric Oxide: a Screening Study.

    PubMed

    Trofimova, E S; Zykova, M V; Ligacheva, A A; Sherstoboev, E Yu; Zhdanov, V V; Belousov, M V; Yusubov, M S; Krivoshchekov, S V; Danilets, M G; Dygai, A M

    2016-09-01

    A screening study of biological activity of native humic acids isolated from peat was performed; several physical and chemical parameters of their structures were studied by UV- and infrared spectroscopy. Spectroscopy yielded similar shape of light absorption curves of humic acids of different origin, which can reflect similarity of general structural principles of these substances. Alkaline humic acids have more developed system of polyconjugation, while molecular structures of pyrophosphate humic acids were characterized by higher aromaticity and condensation indexes. Biological activity of the studied humic acids was assessed by NO-stimulating capacity during their culturing with murine peritoneal macrophages in a wide concentration range. It was shown that due to dose-dependent enhancement of NO production humic acids can change the functional state of macrophages towards development of pro-inflammatory properties. These changes were associated with high activity of humic acids isolated by pyrophosphate extraction, which allows considering effects of isolation method on biological activity.

  10. [Effect of the inoculant strain Sphingomonas paucimobilis 20006FA on the bacterial composition of a phenanthrene-degrading consortium].

    PubMed

    Madueño, L; Coppotelli, B M; Morelli, I S

    2009-01-01

    The effect of the inoculant strain Sphingomonas paucimobilis 20006FA on the bacterial composition of a phenanthrene-degrading consortium obtained from a pristine soil in sequencing batch cultures was studied. Inoculated (F200+1) and non-inoculated (F200) phenanthrene-degrading consortia, were obtained. Bacterial diversity of consortia was studied at cultivable (phenotype and genotype characterization) and non-cultivable (PCR-DGGE) levels. During the successive cultures, a loss in the phenanthrene-degrading capacity and a decrease in the bacterial diversity were observed in both consortia. Although inoculation did not produce any significant changes in the consortia phenanthrene-degrading capacity (29.9% F200 and 27.6% F200+1), it did produce changes in the bacterial composition, showing a differential structural dynamics in the DGGE profiles of the inoculated consortium. In both consortia, a dominant band placed at the same position as that of the DNA of the inoculant strain in the DGGE gel could be observed. However, isolated cultures from the consortia which had an identical band position to that of S. paucimobilis 20006FA in the PCR-DGGE profile showed low similarity with respect to the inoculant strain (RAPD).

  11. CeO2 nanoparticles induce no changes in phenanthrene toxicity to the soil organisms Porcellionides pruinosus and Folsomia candida.

    PubMed

    Tourinho, Paula S; Waalewijn-Kool, Pauline L; Zantkuijl, Irene; Jurkschat, Kerstin; Svendsen, Claus; Soares, Amadeu M V M; Loureiro, Susana; van Gestel, Cornelis A M

    2015-03-01

    Cerium oxide nanoparticles (CeO2 NPs) are used as diesel fuel additives to catalyze oxidation. Phenanthrene is a major component of diesel exhaust particles and one of the most common pollutants in the environment. This study aimed at determining the effect of CeO2 NPs on the toxicity of phenanthrene in Lufa 2.2 standard soil for the isopod Porcellionides pruinosus and the springtail Folsomia candida. Toxicity tests were performed in the presence of CeO2 concentrations of 10, 100 or 1000mg Ce/kg dry soil and compared with results in the absence of CeO2 NPs. CeO2 NPs had no adverse effects on isopod survival and growth or springtail survival and reproduction. For the isopods, LC50s for the effect of phenanthrene ranged from 110 to 143mg/kg dry soil, and EC50s from 17.6 to 31.6mg/kg dry soil. For the springtails, LC50s ranged between 61.5 and 88.3mg/kg dry soil and EC50s from 52.2 to 76.7mg/kg dry soil. From this study it may be concluded that CeO2 NPs have a low toxicity and do not affect toxicity of phenanthrene to isopods and springtails.

  12. Humic acid adsorption and surface charge effects on schwertmannite and goethite in acid sulphate waters.

    PubMed

    Kumpulainen, Sirpa; von der Kammer, Frank; Hofmann, Thilo

    2008-04-01

    In acid conditions, as in acid mine drainage waters, iron oxide particles are positively charged, attracting negatively charged organic particles present in surrounding natural waters. Schwertmannite (Fe8O8(OH)6SO4) and goethite (alpha-FeOOH) are the most typical iron oxide minerals found in mine effluents. We studied schwertmannite formation in the presence of humic acid. Further, surface charge and adsorption of humic acid on synthetic schwertmannite and goethite surfaces in pH 2-9 and in humic acid concentrations of 0.1-100 mg/L C were examined. Schwertmannite did precipitate despite the presence of humic acid, although it contained more sulphate and had higher specific surface area than ordinary schwertmannite. Specific surface area weighted results showed that schwertmannite and goethite had similar humic acid adsorption capacities. Sulphate was released from schwertmannite surfaces with increasing pH, resulting in an increase in specific surface area. Presence of sulphate in solution decreased the surface charge of schwertmannite and goethite similarly, causing coagulation. In acid conditions (pH 2-3.5), according to the zeta potential, schwertmannite is expected to coagulate even in the presence of high concentrations of humic acid (< or = 100 mg/L C). However, at high humic acid concentrations (10-100 mg/L C) with moderate acid conditions (pH>3.5), both schwertmannite and goethite surfaces are strongly negatively charged (zeta potential < -30 mV) thus posing a risk for colloid stabilization and colloidal transport.

  13. Cloud Condensation Nucleus Activity of calcite and calcite coated with model humic and fulvic acids

    NASA Astrophysics Data System (ADS)

    Hatch, C. D.; Gierlus, K. M.; Schuttlefield, J. D.; Grassian, V. H.

    2007-12-01

    Many recent studies have shown that organics can alter the water adsorption and cloud condensation nuclei (CCN) activity of common deliquescent species in the Earth's atmosphere. However, very little is known about the effect of organics on water adsorption and CCN activity of common inactive cloud nuclei, such as mineral aerosol. As many studies have shown that a large fraction of unidentified organic material in aerosol particles is composed of polycarboxylic acids resembling humic substances, the presence of these large molecular weight Humic-Like Substances (HULIS) may also alter the water adsorption and CCN activity of mineral aerosol. Thus, we have measured the water adsorption and CCN activity of model humic and fulvic acids. Additionally, the water adsorption and CCN activity of mineral aerosol particles coated with humic and fulvic acids have been studied. We find that humic and fulvic acids show continual multilayer water adsorption as the relative humidity is raised. Additionally, we find that calcite particles mixed with humic and fulvic acids take up more water by mass, by a factor of two, compared to the uncoated calcite particles at approximately 70% RH. CCN measurements also indicate that internally mixed calcite-humic or fulvic acid aerosols are more CCN active than the otherwise inactive, uncoated calcite particles. Our results suggest that mineral aerosol particles coated with high molecular weight organic materials will take up more water and become more efficient CCN in the Earth's atmosphere than single-component mineral aerosol.

  14. Effect of soil invertebrates on the formation of humic substances under laboratory conditions

    NASA Astrophysics Data System (ADS)

    Frouz, J.; Li, X.; Brune, A.; Pizl, V.; Abakumov, E. V.

    2011-08-01

    The complete polymerization of phenols and proteins (one of the processes involved in the formation of humic substances) was explained. It was shown that fly ( Bibio marci) larvae and earthworms ( Aporrectodea caliginosa) participate in the complete polymerization of phenols and proteins. In a laboratory experiment, invertebrates participated in the degradation of organic matter and the synthesis of humic substances, which was proved in experiments with 14C-labeled phenols and proteins. The same organic substances (phenols and proteins) without the impact of invertebrates were used as the control substances. The distributions of the 14C isotope in alkaline extracts separated by solubility in acids (humic and fulvic acids) was compared to those of the control substances. The portion of the 14C isotope in the humic acids in the excrements of Bibio marci was higher than that in the control substances. The content of 14C-labeled humic substances in the excrements of the earthworm Aporrectodea caliginosa exceeded the control values only in the experiment with proteins. When clay material was added to the organic substances, the portion of the 14C isotope in the humic acids increased in both experiments with phenols and proteins. When these substrates passed through the digestive tracts of the invertebrates, the polymerization of organic substances and the inclusion of proteins and phenols into humic acids occurred.

  15. Pyrolysis GC-MS and NMR studies of humics in contaminated sediments

    SciTech Connect

    Higashi, R.M.; Fan, T.W.M.; Lane, A.N.

    1994-12-31

    Sediment ``humics`` play a major role in sorption and chemical reactions of organic and metal pollutants, as well as of nutrients, detritus, and other naturally-occurring chemicals. Not surprisingly, the chemical structure of humics is very important in this regard. The problem is, humics are among the most complex and least-understood substances in the world. This is because the primary structure is heterologous, unlike most other macromolecules which are polymeric; thus, researchers could not obtain coherent structures to identify with properties. However, recent advances in NMR spectroscopy and pyrolysis GC-MS have enabled researchers to begin relating primary and higher order structural motifs germane to the chemistry of the refractory humics. The authors have explored various means of sediment extraction for humics analysis by these techniques, including direct analysis of unextracted sediments. Marine sediments from near produced water discharges, salt marshes, and dredge material were surveyed. The study has revealed interpretive pitfalls, depending on the method of humic extraction. These difficulties are expected since the approach is at its infancy, but the overall approach is clearly useful in probing the humic structure profile of marine sediments.

  16. Character of Humic Substances as a Predictor for Goethite Nanoparticle Reactivity and Aggregation.

    PubMed

    Vindedahl, Amanda M; Stemig, Melissa S; Arnold, William A; Penn, R Lee

    2016-02-02

    Natural organic matter (NOM) is ubiquitous in surface water and groundwater and interacts strongly with mineral surfaces. The details of these interactions, as well as their impacts on mineral surface reactivity, are not well understood. In this work, both the reactivity and aggregation of goethite (α-FeOOH) nanoparticles were quantified in the presence of well-characterized humic substances. Results from monitoring the kinetics of reductive degradation of 4-chloronitrobenzene (4-ClNB) by Fe(II) adsorbed onto the goethite nanoparticles with and without added humic substances demonstrates that, in all cases, humic substances suppressed Fe(II)-goethite reactivity. The ranking of the standards from the least to most inhibitive was Pahokee Peat humic acid, Elliot Soil humic acid, Suwannee River humic acid, Suwannee River NOM, Suwannee River fulvic acid I, Suwannee River fulvic acid II, and Pahokee Peat fulvic acid. Correlations between eight characteristics (molecular weight, carboxyl concentration, and carbon, oxygen, nitrogen, aliphatic, heteroaliphatic, and aromatic content) and 4-ClNB degradation rate constants were observed. Faster kinetic rates of reductive degradation were observed with increased molecular weight and nitrogen, carbon, and aromatic content, and slower rates were observed with increased carboxyl concentration and oxygen, heteroaliphatic, and aliphatic content. With these correlations, improved predictions of the reactivity of Fe(II)-goethite with pollutants based on properties of the humic substances are possible.

  17. Determination of the phenolic-group capacities of humic substances by non-aqueous titration technique.

    PubMed

    Kirishima, Akira; Ohnishi, Takashi; Sato, Nobuaki; Tochiyama, Osamu

    2009-07-15

    The phenolic-group capacities of five humic substances, such as, the Aldrich humic acid, the humic and fulvic acids extracted from a soil, the humic and fulvic acids extracted from a peat have been precisely determined by the non-aqueous potentiometric titration technique. The titration by KOH in the mixed solvent of DMSO:2-propanol:water=80:19.3:0.7 at [K(+)]=0.02 M enabled to measure the potential change in a wide range of pOH (=-log[OH(-)]), and thus to determine the capacities of phenolic groups which could not be precisely determined in the aqueous titration. The results of the titration revealed that the mean protonation constants of the phenolic groups were nearly the same for all humic substances and close to that of phenol in the same medium, indicating that each phenolic-group in the humic substances is rather isolated and is not electronically affected by other affecting groups in the humic macromolecule.

  18. Potential use of a self-dying reporter bacterium to determine the bioavailability of aged phenanthrene in soil: comparison with physicochemical measures.

    PubMed

    Shin, Doyun; Nam, Kyoungphile

    2014-01-30

    The potential bioavailability of phenanthrene aged in soil was determined by using a self-dying reporter bacterium, and the results were compared to two physicochemical measures, Tenax TA(®) bead-assisted desorption, and hydroxypropyl-β-cyclodextrin (HPCD) extraction. The reporter bacterium, capable of degrading phenanthrene as a sole carbon and energy source, was genetically reconstructed to die when it degrades phenanthrene. Therefore, population change of the reporter cells can be viewed as the quantification of bioavailable phenanthrene. When Ottawa sand was used as an aging matrix, the amounts of bioavailable phenanthrene (i.e. little gradual decrease) were similar, regardless of aging time, and consistent between the reporter bacterium and the two physicochemical measures. However, decrease in bioavailable phenanthrene with aging was readily evident in sandy loam with organic matter of 11.5%, with all three measures. More importantly, when the reporter bacterium was used, a rapid and significant decrease in the bioavailable fraction from 1.00 to 0.0431 was observed. The extent of decrease in bioavailable fraction was less than 40% in the two physicochemical measures, but was nearly 100% in the reporter bacterium, during the first 3 months of aging. Our results suggest that the phenanthrene fraction available to bacterial degradation, and probably the fraction that really manifests toxicity, may be much smaller than the fractions predicted with the physicochemical measures.

  19. Effect of short-chain organic acids on the enhanced desorption of phenanthrene by rhamnolipid biosurfactant in soil-water environment.

    PubMed

    An, Chun-jiang; Huang, Guo-he; Wei, Jia; Yu, Hui

    2011-11-01

    This study investigated the effect of short-chain organic acids on biosurfactant-enhanced mobilization of phenanthrene in soil-water system. The desorption characteristics of phenanthrene by soils were assessed in the presence of rhamnolipid and four SCOAs, including acetic acid, oxalic acid, tartaric acid and citric acid. The tests with rhamnolipid and different organic acids could attain the higher desorption of phenanthrene compared to those with only rhamnolipid. Among the different combinations, the series with rhamnolipid and citric acid exhibited more significant effect on the desorption performance. The removal of phenanthrene using rhamnolipid and SCOAs gradually increased as the SCOA concentration increased up to a concentration of 300 mmol/L. The effects of pH, soil dissolved organic matter and ionic strength were further evaluated in the presence of both biosurfactant and SCOAs. The results showed that the extent of phenanthrene desorption was more significant at pH 6 and 9. Desorption of phenanthrene was relatively lower in the DOM-removed soils with the addition of biosurfactant and SCOAs. The presence of more salt ions made phenanthrene more persistent on the solid phase and adversely affected its desorption from contaminated soil. The results from this study may have important implications for soil washing technologies used to treat PAH-contaminated soil and groundwater.

  20. Biodegradation and adsorption of C1- and C2-phenanthrenes and C1- and C2-dibenzothiophenes in the presence of clay minerals: effect on forensic diagnostic ratios.

    PubMed

    Ugochukwu, Uzochukwu C; Head, Ian M; Manning, David A C

    2014-07-01

    The impact of modified montmorillonites on adsorption and biodegradation of crude oil C1-phenanthrenes, C1-dibenzothiophenes, C2-phenanthrenes and C2-dibenzothiophenes was investigated in aqueous clay/oil microcosm experiments with a hydrocarbon degrading microorganism community. Consequently, the effect on C1-dibenzothiophenes/C1-phenanthrenes, C2-dibenzothiophenes/C2-phenanthrenes, 2+3-methyldibenzothiophene/4-methyldibenzothiophene and 1-methyldibenzothiophene/4-methyldibenzothiophene ratios commonly used as diagnostic ratios for oil forensic studies was evaluated. The clay mineral samples were treated to produce acid activated montmorillonite, organomontmorillonite and homoionic montmorillonite which were used in this study. The different clay minerals (modified and unmodified) showed varied degrees of biodegradation and adsorption of the C1-phenanthrenes, C1-dibenzothiophenes, C2-phenanthrenes and C2-dibenzothiophenes. The study indicated that as opposed to biodegradation, adsorption has no effect on the diagnostic ratios. Among the diagnostic ratios reviewed, only C2-dibenzothiophenes/C2-phenanthrenes ratio was neither affected by adsorption nor biodegradation making this ratio very useful in forensic studies of oil spills and oil-oil correlation.

  1. [Effect of nonionic surfactant Tween80 and DOM on the behaviors of desorption of phenanthrene and pyrene in soil-water systems].

    PubMed

    Wang, Gen-Mei; Sun, Cheng; Xie, Xue-Qun

    2007-04-01

    Batch experiments were conducted to study the effects of dissolved organic matter (DOM) and nonionic surfactant (Tween80) on the desorption of phenanthrene and pyrene in soil-water systems. The results showed that DOM derived from pig manure and pig manure compost increased the desorption of phenanthrene and pyrene in soil-water systems, and the effect of pig manure compost DOM was better than that of pig manure DOM; with the increase of Tween80, the desorption rate of phenanthrene and pyrene also increased compared with the control, especially at high concentration of Tween80 (150 mg x L(-)). And at this concentration, the desorption rates were increased by 1.7 times for phenanthrene and 6.2 times for pyrene than that of the control. The combined effects of Tween80 and DOM on the desorption of phenanthrene and pyrene were influenced by the concentration of Tween80. When Tween80 at low concentration, the combined effects were not significant. Howerver, with 150 mg x L(-1) Tween80 in soil-water systems, the desorption rates of phenanthrene and pyrene were drastically higher than the sum of DOM and Tween80. The results also indicated that DOMs with high molecular-size fraction ( > 25 000 could attain a higher desorption of both phenanthrene and pyrene in soil-water systems than their lowmolecular-size counterpart (< 1000) under the same experiments conditions.

  2. Nonreversible immobilization of water-borne plutonium onto self-assembled adlayers of silanized humic materials.

    PubMed

    Shcherbina, Natalia S; Kalmykov, Stepan S; Karpiouk, Leonid A; Ponomarenko, Sergey A; Hatfield, Kirk; Haire, Richard; Perminova, Irina V

    2014-02-18

    The objective was to study plutonium partitioning between immobile and mobile humic materials at the water-solid interfaces. Immobilization of the humic materials on solid supports was performed in situ using self-adhesive silanized humic derivatives. The presence of the humic adlayers on solid supports was shown to significantly enhance Pu sorption and its retention under both steady state and dynamic conditions. While plutonium may exist in multiple oxidations states plus colloidal forms, the major thrust in this work was to study the behavior of most mobile--the PuO2(+) form in dilute solutions. The values of the plutonium partition coefficients (Kd) between water and humics-coated silica gels after 10 days exposure reached 1.6 × 10(4) L · kg(-1) at pH 7.5 under anaerobic conditions with a total plutonium concentration of 1.2 × 10(-8) M exceeding those for the uncoated SiO2 (6.3 × 10(2) L · kg(-1)). Column tests showed substantial sequestration of water-borne plutonium (up to 73%) on the humics-coated silica gels. Remobilization experiments conducted under batch conditions at different pH values (3.5, 4.5, 7.5) showed that no more than 3% of the sequestered Pu was remobilized from the humics-coated silica gels by treatment with dissolved humic materials at environmentally relevant pH of 7.5. Consequently, silanized humic materialas can be seen as both molecular probes and as potent candidate materials for scavenging mobile Pu from an aqueous phase.

  3. Coupling of carbon and nitrogen cycles through humic redox reactions in an alpine stream

    NASA Astrophysics Data System (ADS)

    McKnight, D.; Cory, R.; Miller, M.; Williams, M.

    2004-05-01

    Humic substances are a heterogeneous class of moderate molecular weight, yellow-colored bio-molecules present in all soils, sediments and natural waters. Although humic substances are generally resistant to microbial degradation under anaerobic conditions, some microorganisms in soils and sediments can use quinone moieties in humic substances as electron acceptors or as electron shuttles in the microbial reduction of ferric iron. In turn, ferrous iron can reduce nitrate, facilitating the formation of organic nitrogen moieties. Field studies of humic electron shuttling processes can be carried out by characterizing the oxidation state of quinone moieties in humic substances at natural concentrations using fluorescence spectroscopy. We have used fluorescence spectroscopy to show that humic substances are important in electron transport reactions in coastal marine sediments and in the water columns of ice-covered lakes. Gradients in humic redox state may also occur as stream water is exchanged with water in associated hyporheic zones. We conducted a conservative tracer injection experiment in an alpine stream-wetland system located in the Front Range of the Colorado Rocky Mountains. In this system, concentrations of nitrate and dissolved organic carbon both increase with the onset of snowmelt as nitrate deposited in the snowpack is mobilized and DOC is flushed from upper soil horizons. During the tracer experiment, we sampled wells adjacent to the stream and found that lower nitrate concentrations occurred in wells with slower hyporheic exchange and more reduced dissolved humic substances. These results suggest that humic redox shuttling may be an important process linking carbon, nitrogen and iron cycling in watersheds.

  4. Properties and structure of peat humic acids depending on humification and precursor biota in bogs

    NASA Astrophysics Data System (ADS)

    Klavins, Maris; Purmalis, Oskars

    2013-04-01

    Humic substances form most of the organic component of soil, peat and natural waters, but their structure and properties very much differs depending on their source. The aim of this study is to characterize humic acids from raised bog peat profiles to evaluate the homogeneity of humic acids isolated from the bog bodies and study peat humification impact on properties of humic acids. A major impact on the structure of peat humic acids have raised bog biota (dominantly represented by bryophytes of different origin) void of lignin. For characterization of peat humic acids their elemental (CHNOS), functional (-COOH, phenolic OH) analysis, spectroscopic characterization (UV, fluorescence, FTIR, 1H NMR, CP/MAS 13C NMR, ESR) and degradation studies (Py-GC/MS) were done. Peat humic acids (HA) have an intermediate position between the living organic matter and coal organic matter and their structure is formed in a process in which more labile structures (carbohydrates, amino acids, etc.) are destroyed, but thermodynamically more stable aromatic and polyaromatic structures emerge. Comparatively, the studied peat HAs are at the start of the transformation process of living organic matter. Concentrations of carboxyl and phenolic hydroxyl groups changes depending on the depth of peat from which HAs have been isolated: and carboxylic acidity is increasing with depth of peat location and the humification degree. The ability to influence the surface tension of peat humic acids isolated from a well-characterized bog profile demonstrates dependence on age and humification degree. With increase of the humification degree and age of humic acids, their molecular complexity and ability to influence surface tension decreases; even so, the impact of the biological precursor (peat-forming bryophytes and plants) can be identified.

  5. Aryl hydrocarbon receptor protein and Cyp1A1 gene induction by LPS and phenanthrene in Atlantic cod (Gadus morhua) head kidney cells.

    PubMed

    Holen, Elisabeth; Olsvik, Pål Asgeir

    2014-10-01

    The objective of this study was to evaluate interactions between environmental toxicants and cod immune cells during inflammation. Phenanthrene is abundant in plant oils (rapeseed, palm, and soya oil) as compared to fish oils, and consequently constitute an undesirable element in plant replacement diets in aquaculture. Phenanthrene was added to head kidney cell cultures, alone or together with LPS (lipopolysaccharide) or poly I: C (polyinosinic acid: polycytidylic acid), and the responses were evaluated in terms of protein and gene expression. The results showed that LPS, poly I: C or phenanthrene, added to the cultures separately, induced aryl hydrocarbon receptor (AhR) protein expression. Phenanthrene treatment in combination with LPS induced AhR protein expression and Cyp1A1 gene transcription, which not was observed combining poly I: C and phenanthrene. Phenanthrene exposure up regulated the transcription of common stress and detoxification enzymes like catalase, caspase 3 and glutathione S-transferase alfa 3 subunit B (GSTAB3), while LPS exposure alone or combined with phenanthrene down regulated GSTAB3 and catalase in cod leukocytes. It seems clear that immune regulation and phenanthrene induced signaling pathways interact; transcriptional down regulation of detoxification and antioxidant enzymes by LPS could indicate that combating bacterial infections is the number one priority in these cells, and that AhR and Cyp1A1 is somehow involved in this signaling cascade. LPS seems to affect the mitogen activated protein kinases (MAPKs) pathways (P-p38 and ERK1/2) thus modulating the AhR protein and Cyp1A1 gene transcription, while phenanthrene possibly activates AhR by ligand binding.

  6. Simple method of isolating humic acids from organic soils

    NASA Astrophysics Data System (ADS)

    Ahmed, O.

    2009-04-01

    Humic substances particularly humic acids (HA) play a major role in soil conditioning e.g. erosion control, soil cation exchange capacity, complexation of heavy metal ions and pesticides, carbon and nitrogen cycles, plant growth and reduction of ammonia volatilization from urea. Humified substances such as coal, composts, and peat soils have substantial amounts of HA but the isolation of these acids is expensive, laborious, and time consuming. Factors that affect the quality and yield of HA isolated from these materials include extraction, fractionation, and purification periods. This work developed a simple, rapid, and cost effective method of isolating HA from peat soils. There was a quadratic relationship between extraction period and HA yield. Optimum extraction period was estimated at 4 h instead of the usual range of 12 to 48 h. There was no relationship between fractionation period and HA yield. As such 2 h instead of the usual range of 12 to 24 h fractionation period could be considered optimum. Low ash content (5%), remarkable reduction in K, coupled with the fact that organic C, E4/E6, carboxylic COOH, phenolic OH, and total acidity values of the HA were consistent with those reported by other authors suggest that the HA dealt with were free from mineral matter. This was possible because the distilled water used to purify the HA served as Bronsted-Lowry acid during the purification process of the HA. Optimum purification period using distilled waster was 1 h instead of the usual range of 1 and 7 days (uses HF and HCl and dialysis). Humic acids could be isolated from tropical peat soils within 7 h (i.e. 4 h extraction, 2 h fractionation, and 1 h purification) instead of the existing period of 2 and 7 days. This could facilitate the idea of producing organic fertilizers such as ammonium-humate and potassium-humate from humified substances since techniques devised in this study did not alter the true nature of the HA. Besides, the technique is rapid, simple

  7. Stabilization of polynuclear plutonium(IV) species by humic acid

    NASA Astrophysics Data System (ADS)

    Marsac, Rémi; Banik, Nidhu Lal; Marquardt, Christian Michael; Kratz, Jens Volker

    2014-04-01

    Although the formation of tetravalent plutonium (Pu(IV)) polymers with natural organic matter was previously observed by spectroscopy, there is no quantitative evidence of such reaction in batch experiments. In the present study, Pu(IV) interaction with humic acid (HA) was investigated at pH 1.8, 2.5 and 3, as a function of HA concentration and for Pu total concentration equal to 6 × 10-8 M. The finally measured Pu(IV) concentrations ([Pu(IV)]eq) are below Pu(IV) solubility limit. Pu(IV)-HA interaction can be explained by the complexation of Pu(IV) monomers by HA up to [Pu(IV)]eq ∼ 10-8 M. However, the slope of the log-log Pu(IV)-HA binding isotherm changes from ∼0.7 to ∼3.5 for higher [Pu(IV)]eq than ∼10-8 M and at any pH. This result suggests the stabilization of hydrolyzed polymeric Pu(IV) species by HA, with a 4:1 Pu:HA stoichiometry. This confirms, for the first time, previous observations made by spectroscopy in concentrated systems. The humic-ion binding model, Model VII, was introduced into the geochemical speciation program PHREEQC and was used to simulate Pu(IV) monomers binding to HA. The simulations are consistent with other tetravalent actinides-HA binding data from literature. The stabilization of a Pu tetramer (Pu4(OH)88+) by HA was proposed to illustrate the present experimental results for [Pu(IV)]eq > 10-8 M. Predictive simulations of Pu(IV) apparent solubility due to HA show that the chosen Pu(IV)-polymer has no impact for pH > 4. However, the comparison between these predictions and recent spectroscopic results suggest that more hydrolyzed polymeric Pu(IV) species can be stabilized by HA at pH > 4. Polymeric Pu(IV)-HA species might significantly enhance Pu(IV) apparent solubility due to humics, which support a colloid-facilitated transport of this low solubility element.

  8. Modelling of Rare Earth Elements Complexation With Humic Acid

    NASA Astrophysics Data System (ADS)

    Pourret, O.; Davranche, M.; Gruau, G.; Dia, A.

    2006-12-01

    The binding of rare earth elements (REE) to humic acid (HA) was studied by combining Ultrafiltration and ICP- MS techniques. REE-HA complexation experiments were performed at various pH conditions (ranging from 2 to 10.5) using a standard batch equilibration method. Results show that the amount of REE bound to HA strongly increase with increasing pH. Moreover, a Middle REE (MREE) downward concavity is evidenced by REE distribution patterns at acidic pH. Modelling of the experimental data using Humic Ion Binding Model VI provided a set of log KMA values (i.e. the REE-HA complexation constants specific to Model VI) for the entire REE series. The log KMA pattern obtained displays a MREE downward concavity. Log KMA values range from 2.42 to 2.79. These binding constants are in good agreement with the few existing datasets quantifying the binding of REE with humic substances except a recently published study which evidence a lanthanide contraction effect (i.e. continuous increase of the constant from La to Lu). The MREE downward concavity displayed by REE-HA complexation pattern determined in this study compares well with results from REE-fulvic acid (FA) and REE-acetic acid complexation studies. This similarity in the REE complexation pattern shapes suggests that carboxylic groups are the main binding sites of REE in HA. This conclusion is further supported by a detailed review of published studies for natural, organic-rich, river- and ground-waters which show no evidence of a lanthanide contraction effect in REE pattern shape. Finally, application of Model VI using the new, experimentally determined log KMA values to World Average River Water confirms earlier suggestions that REE occur predominantly as organic complexes (> 60 %) in the pH range between 5-5.5 and 7-8.5 (i.e. in circumneutral pH waters). The only significant difference as compared to earlier model predictions made using estimated log KMA values is that the experimentally determined log KMA values

  9. The interaction between humic acid and naphthalene after exposure to visible and UV light

    NASA Astrophysics Data System (ADS)

    Nechaev, L. V.; Tchaikovskaya, O. N.

    2015-12-01

    Dissolved organic matter plays an important role in pollution migration from human waste to aquatic environments. In this study, the effect of humic acid (HA) on the photo-chemical transformation of naphthalene by irradiation model solar and UV light was reported using fluorescence quenching titrations. It was calculated the interactions between naphthalene and humic acids. It is found that the molecular complex of humic acid and naphthalene is more stable to UV irradiation, compared with the model solar radiation. The application of molecular fluorescence spectrometry is a useful sensitive tool evaluate intermolecular HA and naphthalene interactions.

  10. Pyrolysis-mass spectrometry/pattern recognition on a well-characterized suite of humic samples

    USGS Publications Warehouse

    MacCarthy, P.; DeLuca, S.J.; Voorhees, K.J.; Malcolm, R.L.; Thurman, E.M.

    1985-01-01

    A suite of well-characterized humic and fulvic acids of freshwater, soil and plant origin was subjected to pyrolysis-mass spectrometry and the resulting data were analyzed by pattern recognition and factor analysis. A factor analysis plot of the data shows that the humic acids and fulvic acids can be segregated into two distinct classes. Carbohydrate and phenolic components are more pronounced in the pyrolysis products of the fulvic acids, and saturated and unsaturated hydrocarbons contribute more to the humic acid pyrolysis products. A second factor analysis plot shows a separation which appears to be based primarily on whether the samples are of aquatic or soil origin. ?? 1985.

  11. Humic derivatives as promising hormone-like materials

    NASA Astrophysics Data System (ADS)

    Koroleva, R. P.; Khudaibergenova, E. M.; Kydralieva, K. A.; Jorobekova, Sh. J.

    2009-04-01

    The aim of this research is to prepare novel bio-inoculants derived from coal humic substances (HS) using bio-solubilization technique. This approach can be considered to some extent as model for supply plants with available nutrients throw the mineralisation of organic matter in soils by bacteria and fungi. Screening for the stable and active microorganisms' strains possessing ability to degrade humic substances was performed. The following subjects were examined using different isolation methods: natural microbial population from city soil, wood rot of Ulmis Pamila and biohumus of vermiculture of Eisenia foetida. Approaches for monitoring the humics-solubilizing fungi growth under liquid surface conditions in the presence of HS, proper conditions of bio-solubilization technique were elaborated. Coal humic acids (HA) from oxidized brown coal (Kyrgyz deposits) were isolated and added to a Czapek nutrient broth which was used either in full strength or without nitrogen source. The individual flasks were inoculated with natural microbial populations of corresponding cultivated soil, biohumus and wood rot samples for 12 months. Evaluation of phyto-hormonal activity of the produced HS and their derivatives in respect to higher plants with auxine and gibberellic tests was performed. To characterize structure of the biopreparations obtained, an experimental approach was undertaken that implies application of different complementary techniques for the structural analysis of biopreparations. As those were used: elemental and functional analysis, FTIR and 1H, 13C NMR spectroscopy and size-exclusion chromatography. According to the elemental composition of HS recovered from microbial cultures, a decrease in carbon and a significant increase of nitrogen in HS reisolated from the full strength broth inoculated with wood-decay microorganisms has been found. If biohumus microorganisms were used as inoculum, only minor changes were detected in the elemental composition of HS. A

  12. Soil humic substances hinder the propagation of prions

    NASA Astrophysics Data System (ADS)

    Leita, Liviana; Giachin, Gabriele; Margon, Alja; Narkiewicz, Joanna; Legname, Giuseppe

    2013-04-01

    capacity of clay minerals; however the contribution of soil organic components in adsorption has so far been neglected, as they represent a minor soil fraction on a weight basis. Among organic molecules, humic substances (HSs) are natural polyanions that result among the most reactive compounds in the soil and possess the largest specific surface area. Humic substances make up a large portion of the dark matter in humus and consist of heterogeneous mixtures of transformed biomolecules exhibiting a supramolecular structure. HSs are classified as humic acids (HAs), which are soluble only in alkaline solutions, and fulvic acids (FAs), which are soluble in both alkaline and acid solutions. The amphiphilic characteristics confer to HAs and FAs great versatility to interact with xenobiotics and reasonably also with prion proteins and/or prions too, leading to the formation of adducts with peculiar chemical and biophysical characteristics, thus affecting the transport, fixation and toxicity of prion. Results from our chemical, biophysical and biochemical investigation will be presented and results on anti-prion activity exerted by HAs and FAs will be provided, thus suggesting that amendment of contaminated soil with humic substances could be a strategy to contrast prion diffusion.

  13. Characterization of humic substances by environmental scanning electron microscopy.

    PubMed

    Redwood, Paul S; Lead, Jamie R; Harrison, Roy M; Jones, Ian P; Stoll, Serge

    2005-04-01

    Environmental scanning electron microscopy (ESEM) is a new technique capable of imaging micron and submicron particles. Here, we have applied it to image and quantify natural aquatic organic matter (standard Suwannee River humic acid, SRHA). Uniquely, we have observed the humic aggregate structures as a function of humidity and pH. Large aggregates of tens of micrometers were observed as the dominant material under all conditions, although much smaller material was also observed. Fractal dimensions (D) were calculated between 1.48 and 1.70, although these values were not statistically different under conditions of low humidity. However, D values calculated at high humidities (85%) during the rehydration phase were significantly lower (1.48+/-0.01) than in the initial dehydration phase (1.69+/-0.01). This hysteresis indicated that full rehydration of the HS was either kinetically slow or irreversible after dehydration. Fractal analysis of ESEM images was also performed to probe the change in aggregate structure as a function of pH. Minimum values were calculated at neutral pHs, rising by 0.1-0.2 at both high and low pHs because of a combination of the physical chemistry of HS and the impacts of the drying regime within the ESEM. Thus, ESEM was an important complementary technique to other analytical methods. At present, ESEM cannot be used to image nonperturbed natural samples. However, the method is an ideal method for probing the changes in colloid structure as function of hydration state and has the potential to perform fully quantitative and nonperturbing analysis of colloidal structure.

  14. [Influence of dissolved organic matter on the eco-toxicity of phenanthrene in a soil].

    PubMed

    Zhan, Xin-hua; Wan, Yin-jing; Zhou, Li-xiang

    2004-05-01

    Biological and physico-chemistry experiments were conducted to study the effects of dissolved organic matter (DOM) on eco-toxicity of phenanthrene in a soil. The results showed that DOM was a kind of surfactant. The sensitive range of phe inhibiting wheat root elongation was from 0 to 200 mg/kg, and median inhibition concentration (IC50) was 200 mg/kg. In the presence of DOM, the eco-toxicity of phe could be alleviated and the inhabited degree was related to the content of hydrophobic components and surface activity. This effect could be strengthened by the high concentration of DOM. As a kind of hydrophobic organic compound, phe could reduce the moisture of topsoil, and DOM would slightly increase the moisture of topsoil polluted by phe. It was concluded that DOM could lighten the eco-toxicity of phe in soil.

  15. Solid-liquid equilibria for binary mixtures composed of acenaphthene, dibenzofuran, fluorene, phenanthrene, and diphenylmethane

    SciTech Connect

    Lee, M.J.; Chen, C.H.; Lin, H.

    1999-09-01

    The liquidus lines were determined with a solid-disappearance method for binary mixtures composed of acenaphthene, dibenzofuran, fluorene, phenanthrene, and diphenylmethane. While the first four substances are model compounds of wash oil, which has widely been used as a solvent to remove aromatics from coal oven gas, diphenylmethane is a high-boiling and low-melting compound that is a potential additive to modify the performance of wash oil. Each of the seven binaries appears to be a simple eutectic system, as evidenced by the experimental results. The Wilson and the NRTL models were employed to correlate the solid-liquid equilibrium data. Both activity coefficient models were found to represent accurately the nonideality of the liquid-phase for the investigated systems.

  16. NAH plasmid-mediated catabolism of anthracene and phenanthrene to naphthoic acids.

    PubMed Central

    Menn, F M; Applegate, B M; Sayler, G S

    1993-01-01

    Pseudomonas fluorescens 5R contains an NAH7-like plasmid (pKA1), and P. fluorescens 5R mutant 5RL contains a bioluminescent reporter plasmid (pUTK21) which was constructed by transposon mutagenesis. Polymerase chain reaction mapping confirmed the localization of lux transposon Tn4431 300 bp downstream from the start of the nahG gene. Two degradation products, 2-hydroxy-3-naphthoic acid and 1-hydroxy-2-naphthoic acid, were recovered and identified from P. fluorescens 5RL as biochemical metabolites from the biotransformation of anthracene and phenanthrene, respectively. This is the first report which provides direct biochemical evidence that the naphthalene plasmid degradative enzyme system is involved in the degradation of higher-molecular-weight polycyclic aromatic hydrocarbons other than naphthalene. Images PMID:8328810

  17. Evaluation of the application potential of bentonites in phenanthrene bioremediation by characterizing the biofilm community.

    PubMed

    Huang, Yili; Zhang, Jing; Zhu, Lizhong

    2013-04-01

    Application of clay minerals in bioremediation has emerged as a new and promising research field. In this study, the application of calcinated bentonite (CB) and calcinated organobentonite (COB) in phenanthrene (Phe) bioremediation showed high Phe removal efficiency. Clone libraries based on 16S rRNA gene and scanning electronic microscopy showed that diverse taxa of bacteria formed biofilms on both COB and CB particles. The family Sphingomonadaceae was the major group and made up 18% and 23% of the COB and CB biofilm composition, respectively. All and 80% of dioxygenase genes from COB and CB biofilms were closely related to that of Sphingomonas sp., and others matched to that of Comamonas and Mycobacterium. The selective effect of COB on bacterial community was also evident. This study characterized for the first time the bacterial diversity of biofilm community and functional Phe degrading groups on bentonites particles, and provided useful information for future applications.

  18. Adsorption of phenanthrene by quaternary ammonium surfactant modified peat and the mechanism involved.

    PubMed

    Zhou, Y B; Chen, L; Wang, X Q; Xu, Y X; Lu, J

    2012-01-01

    Removal of phenanthrene (PHE) from aqueous solution by adsorption onto quaternary ammonium surfactant modified peat was studied. The results show that surfactant modification enhanced the PHE adsorption capacity of peat. Low temperature and neutral pH favored PHE adsorption. Peat modified with long carbon chain surfactant performed better than peat modified with short carbon chain surfactant. The magnitude of PHE adsorption capacity followed the order of MP-HPB>MP-HTAB>MP-TBAB>RP, ranged from 924 to 1,228 μg g(-1). A negative trend between adsorption capacity (y) and (O+N)/C ratio of biosorbent (x) was observed (y = -1,369.6x + 2,176), which confirmed the negative effect of polarity on polycyclic aromatic hydrocarbon (PAH) removal. The study provides a guide to modify raw materials to enhance adsorption of hydrophobic organics.

  19. The growth, photosynthesis and antioxidant defense responses of five vegetable crops to phenanthrene stress.

    PubMed

    Ahammed, Golam Jalal; Wang, Meng-Meng; Zhou, Yan-Hong; Xia, Xiao-Jian; Mao, Wei-Hua; Shi, Kai; Yu, Jing-Quan

    2012-06-01

    Polycyclic aromatic hydrocarbons (PAHs) are global environmental problem. To better understand the growth and physiological responses to atmospheric PAHs, we investigated biomass, photosynthetic machinery and antioxidant system in pakchoi, cucumber, flowering chinese cabbage, tomato and lettuce under various levels of phenanthrene (PHE) stress. Foliar exposure to PHE for 14d resulted in a dose dependent decrease in growth, photosynthesis and chlorophyll contents. With few exceptions, antioxidant enzymes (superoxide dismutase, guaicol peroxidase, catalase, ascorbate peroxidase and glutathione reductase) were upregulated following exposure to PHE. Dose dependent increase in malondialdehyde contents together with H(2)O(2) accumulation suggested an occurrence of oxidative stress following PHE exposure. However, to some extent, growth and antioxidant defense responses differ from species to species. Difference in defense capacity might result in different tolerance and phytotoxicity among the studied vegetables. Taken together, phytotoxicity of PHE to five vegetables could be sequenced in the following order: pakchoi>cucumber>lettuce>tomato>flowering chinese cabbage.

  20. Planar conjugated polymers containing 9,10-disubstituted phenanthrene units for efficient polymer solar cells.

    PubMed

    Li, Guangwu; Kang, Chong; Li, Cuihong; Lu, Zhen; Zhang, Jicheng; Gong, Xue; Zhao, Guangyao; Dong, Huanli; Hu, Wenping; Bo, Zhishan

    2014-06-01

    Four novel conjugated polymers (P1-4) with 9,10-disubstituted phenanthrene (PhA) as the donor unit and 5,6-bis(octyloxy)benzothiadiazole as the acceptor unit are synthesized and characterized. These polymers are of medium bandgaps (2.0 eV), low-lying HOMO energy levels (below -5.3 eV), and high hole mobilities (in the range of 3.6 × 10(-3) to 0.02 cm(2) V(-1) s(-1) ). Bulk heterojunction (BHJ) polymer solar cells (PSCs) with P1-4:PC71 BM blends as the active layer and an alcohol-soluble fullerene derivative (FN-C60) as the interfacial layer between the active layer and cathode give the best power conversion efficiency (PCE) of 4.24%, indicating that 9,10-disubstituted PhA are potential donor materials for high-efficiency BHJ PSCs.

  1. Enhanced electrokinetic removal of phenanthrene from clay soil by periodic electric potential application.

    PubMed

    Reddy, Krishna R; Saichek, Richard E

    2004-01-01

    Electrokinetically enhanced in-situ flushing using surfactants has the potential to remove polycyclic aromatic hydrocarbons (PAHs) from low permeability clay soils; however, previous research has shown that the applied electric potential produces complex physical, chemical, and electrochemical changes within clay soils that affect mass transfer and overall efficiency. This article presents the results of a laboratory investigation conducted to determine the contaminant mass removal by using a periodic voltage application. The periodic voltage effects were evaluated by performing four different bench-scale electrokinetic tests with the voltage gradient applied continuously or periodically, under relatively low voltage (1.0 VDC/cm) and high anode buffering (0.1 M NaOH) as well as high voltage (2.0 VDC/cm) and low anode buffering (0.01 M NaOH) conditions. For all the tests, kaolin soil was used as a representative clay soil and it was spiked with phenanthrene, a representative PAH, with a target concentration of 500 mg/kg. A nonionic polyoxyethylene surfactant, Igepal CA 720, was used as the flushing solution in all the tests. The voltage was applied according to a cycle of five days of continuous application followed by two days of "down time," when the voltage was not applied. The results of these experiments show that considerable contaminant removal can be achieved by employing a high, 2.0 VDC/cm, voltage gradient along with a periodic mode of voltage application. The increased removal was attributed to increased phenanthrene solubilization and mass transfer due to the reduced flow of the bulk solution during the down time as well as to the pulsed electroosmotic flow that improved flushing action.

  2. Photodegradation of phenanthrene by N-doped TiO2 photocatalyst.

    PubMed

    Sirisaksoontorn, Weekit; Thachepan, Surachai; Songsasen, Apisit

    2009-07-15

    The photodegradation of phenanthrene has been catalyzed by nanostructures of TiO2 doped with nitrogen, N-doped TiO2. The N-doped TiO2 was prepared from the sol-gel reaction of Titanium(IV) bis(ethyl acetoacetato)diisopropoxide with 25% ammonia solution. The N-doped TiO2 was calcined at various temperatures from 300 to 700 degrees C. X-ray diffraction (XRD) results showed that N-doped TiO2 remained amorphous at 300 degrees C but anatase-to-rutile transformation started at 400 degrees C and was complete at 700 degrees C. The average particle size calculated from Scherrer's equation was in the range of 9-51 nm with surface area (S(BET)) of 253.7-4.8 m2/g. X-ray photoelectron spectroscopy (XPS) results confirmed the incorporation of nitrogen atoms (Ti-N bond) in the N-doped catalyst. Moreover, the percentage of nitrogen determined by Elemental analysis was 0.236% of N-doped calcined at 400 degrees C. UV-Vis reflection spectra indicated that N-doped TiO2 calcined at 400 degrees C shifted to the higher absorption edge in the range of visible light. N-doped TiO2 calcined at 400 degrees C successfully catalyzed the photodegradation of phenanthrene (80% conversion) whereas N-doped TiO2 calcined at 500 degrees C and P25 TiO2 failed as catalysts.

  3. 40 CFR 795.70 - Indirect photolysis screening test: Sunlight photolysis in waters containing dissolved humic...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... solar irradiance during the reaction period, an actinometer is simultaneously insolated. From these data.... This condition exists because the solar action spectrum for indirect photoreaction in humic-containing... also solar irradiance variations, tubes containing SHW and actinometer solutions are...

  4. 40 CFR 795.70 - Indirect photolysis screening test: Sunlight photolysis in waters containing dissolved humic...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... solar irradiance during the reaction period, an actinometer is simultaneously insolated. From these data.... This condition exists because the solar action spectrum for indirect photoreaction in humic-containing... also solar irradiance variations, tubes containing SHW and actinometer solutions are...

  5. Comparative studies of the reduction behavior of chromium(VI) by humic substances and their precursors

    SciTech Connect

    Nakayasu, Ken; Sasaki, Keiko; Tanaka, Shunitz; Nakamura, Hiroshi ); Fukushima, Masami )

    1999-06-01

    Hexavalent chromium (Cr[VI]) is reduced by dissolved organic carbons (DOCs) such as humic substances, tannic acid (TA), and gallic acid (GA). The kinetic constants and the resulting chemical species after the reduction were compared with each other. The kinetic constants for GA and TA, which are model precursors of humic substances, were two to three orders of magnitude larger than those for the humic substances when these kinetic constants were expressed as a function of the molar concentration of the reductive functional group (F[sub red]) in various DOCs. After the reduction of Cr(VI), the percentages of the species complexed with GA and TA were higher than those with the humic substances. This appears to be due to the formation of high molecular weight compounds by polymerization during the reduction of Cr(VI) and complexation of Cr(III) with the polymerized compounds. The UV-vis spectrophotometric data and gel permeation chromatography support this view.

  6. CAPILLARY ELECTROPHORESIS IN THE ANALYSIS OF HUMIC SUBSTANCES FACTS AND ARTIFACTS

    EPA Science Inventory

    Humic substances, extracted as mixtures from soil and surface waters according to their solubility in acids and bases, are relatively high-molecular-mass polyelectrolytes containing aromatic, aliphatic and heterocyclic subunits. The degree of ionization of their phenolic and carb...

  7. Limitations in the use of commercial humic acids in water and soil research

    USGS Publications Warehouse

    Malcolm, R.L.; MacCarthy, P.

    1986-01-01

    Seven samples of commercial "humic acids", purchased from five different suppliers, were studied, and their characteristics were compared with humic and fulvic acids isolated from streams, soils, peat, leonardite, and a dopplerite sample. Cross-polarization and magic-angle spinning 13C NMR spectroscopy clearly shows pronounced differences between the commercial materials and all other samples. Elemental and infrared spectroscopic data do not show such clear-cut differences but can be used as supportive evidence, with the 13C NMR data, to substantiate the above distinctions. As a result of these differences and due to the general lack of information relating to the source, method of isolation, or other pretreatment of the commercial materials, these commercial products are not considered to be appropriate for use as analogues of true soil and water humic substances, in experiments designed to evaluate the nature and reactivity of humic substances in natural waters and soils.

  8. Intrahorizon differentiation of the structural-functional parameters of the humic acids from a typical chernozem

    NASA Astrophysics Data System (ADS)

    Chukov, S. N.; Golubkov, M. S.; Ryumin, A. G.

    2010-11-01

    It is shown that some structural-functional parameters of humic acids from the surface (0-5 cm) layer of a typical chernozem differ from those in a deeper (5-20 cm) layer. The Cha-to-Cfa ratio in the surface layer is by 1.7 times lower, and the concentration of free radicals is by almost an order of magnitude lower than that in the layer of 5-20 cm. The stimulating effect of humic acids from the surface layer on the processes of photosynthesis is sharply retarded, whereas their effect on respiration of Chlorella vulgaris is more pronounced. Humic acids from the deeper layer of chernozem have a much stronger stimulating effect on photosynthesis and a very weak stimulating effect of respiration. The concentration of free radicals in humic acids and the activity of physiological processes of photosynthesis in Chlorella vulgaris display a tight correlative relationship.

  9. Decreased solubilization of Pu(IV) polymers by humic acids under anoxic conditions

    NASA Astrophysics Data System (ADS)

    Xie, Jinchuan; Lin, Jianfeng; Liang, Wei; Li, Mei; Zhou, Xiaohua

    2016-11-01

    Pu(IV) polymer has a very low solubility (log[Pu(IV)aq]total = -10.4 at pH 7.2 and I = 0). However, some aspects of their environmental fate remain unclear. Humic acids are able to complex with Pu4+ ions and their dissolved species (<10 kD) in the groundwater (neutral to alkaline pH) may cause solubilization of the polymers. Also, humic acids have the native reducing capacity and potentially reduce the polymeric Pu(IV) to Pu(III)aq (log[Pu(III)aq]total = -5.3 at pH 7.2 and I = 0). Solubilization and reduction of the polymers can enhance their mobility in subsurface environments. Nevertheless, humic acids readily coat the surfaces of metal oxides via electrostatic interaction and ligand exchange mechanisms. The humic coatings are expected to prevent both solubilization and reduction of the polymers. Experiments were conducted under anoxic and slightly alkaline (pH 7.2) conditions in order to study whether humic acids have effects on stability of the polymers. The results show that the polymeric Pu(IV) was almost completely transformed into aqueous Pu(IV) in the presence of EDTA ligands. In contrast, the dissolved humic acids did not solubilize the polymers but in fact decreased their solubility by one order of magnitude. The humic coatings were responsible for the decreased solubilization. Such coatings limited the contact between the polymers and EDTA ligands, especially at the relatively high concentrations of humic acids (>0.57 mg/L). Solubilization of the humic-coated polymers was thus inhibited to a significant extent although EDTA, having the great complexation ability, was present in the humic solutions. Reduction of Pu(IV) polymers by the humic acids was also not observed in the absence of EDTA. In the presence of EDTA, the polymers were partially reduced to Pu(III)aq by the humic acids of 0.57 mg/L and the percentage of Pu(III)aq accounted for 51.7% of the total aqueous Pu. This demonstrates that the humic acids were able to reduce the aqueous Pu

  10. Evaluation of humic fractions potential to produce bio-oil through catalytic hydroliquefaction.

    PubMed

    Lemée, L; Pinard, L; Beauchet, R; Kpogbemabou, D

    2013-12-01

    Humic substances were extracted from biodegraded lignocellulosic biomass (LCBb) and submitted to catalytic hydroliquefaction. The resulting bio-oils were compared with those of the initial biomass. Compared to fulvic and humic acids, humin presented a high conversion rate (74 wt.%) and the highest amount of liquid fraction (66 wt.%). Moreover it represented 78% of LCBb. Humin produced 43 wt.% of crude oil and 33 wt.% of hexane soluble fraction containing hydrocarbons which is a higher yield than those from other humic substances as well as from the initial biomass. Hydrocarbons were mainly aromatics, but humin produces the highest amount of aliphatics. Considering the quantity, the quality and the molecular composition of the humic fractions, a classification of the potential of the latter to produce fuel using hydroliquefaction process can be assess: Hu>AF>AH. The higher heating value (HHV) and oxygen content of HSF from humin were fully compatible with biofuel characteristics.

  11. Study of coagulation processes of selected humic acids under copper ions influence*

    NASA Astrophysics Data System (ADS)

    Boguta, Patrycja; Sokolowska, Zofia

    2013-04-01

    Humic acids have limited sorption capacity and big dose of metal or other mineral component which can be sorbed on humic acids, can cause saturation of negative, surface charge of humic acids leading to destabilization of dissolved humic acids compounds. Destabilisation can be observed as coagulation and floculation proces of humic acids. However there are a lot of mechanisms which causing precipitation of humic acids. Thereby, in order to full description of coagulation process, different methods should be applied. Ordinarily, humic acids coagulation is studied by measurement of absorbance, transmittance or carbon loss in solution. Meanwhile, very significant information is also variation of metal content in soil solution and information whether metal goes to precipitate together with humic acids or stays in dissolved form in solution. So, that, from one side, processes of stronger accumulation of metal can lead to soil degradation and micronutrient deficiency for plants. However, there is also possibility to stay metal in solution in toxic and bioavailable form for plants. Main aim of this paper was to study coagulation process of different humic acids extracted from mucking peats under copper ions influence at adjusted pH to 5. In order to this, four peaty-muck soils were taken from selected places in east part of Poland (meadows and river valleys). These soils differed by humification degree, secondary transformation, density and pH. At next step, humic acids were extracted from soils using sodium hydroxide (NaOH) extractant. After exact purification by washing with HF-HCl mixture and water, humic acids were liofilized. Solutions of humic acids were prepared at concentration 40 mg/dm3 with addition of different amount of copper ions to obtain final concentration of Cu(II) ranged from 0-40mg/dm3. After 24 hours solutions were investigated using measurements of absorbance at 470nm (UV-VIS spectrometer Jasco V-530), measurements of organic carbon in solution

  12. Redox and complexation interactions of neptunium(V) with quinonoid-enriched humic derivatives.

    PubMed

    Shcherbina, Natalia S; Perminova, Irina V; Kalmykov, Stepan N; Kovalenko, Anton N; Haire, Richard G; Novikov, Alexander P

    2007-10-15

    Actinides in their higher valence states (e.g., MO2+ and MO2(2+), where M can be Np, Pu, etc) possess a higher potential for migration and in turn pose a substantial environmental threat. To minimize this potential for migration, reducing them to lower oxidation states (e.g., their tetravalent state) can be an attractive and efficient remedial process. These lower oxidation states are often much less soluble in natural aqueous media and are, therefore, less mobile in the environment. The research presented here focuses on assessing the performance of quinonoid-enriched humic derivatives with regardsto complexing and/ or reducing Np(V) present in solution. These "designer" humics are essentially derived reducing agents that can serve as reactive components of a novel humic-based remediation technology. The derivatives are obtained by incorporating different quinonoid-moieties into leonardite humic acids. Five quinonoid-derivatives are tested in this work and all five prove more effective as reducing agents for selected actinides than the parent leonardite humic acid, and the hydroquinone derivatives are better than the catechol derivatives. The reduction kinetics and the Np(V) species formed with the different derivatives are studied via a batch mode using near-infrared (NIR)-spectroscopy. Np(V) reduction by the humic derivatives under anoxic conditions at 293 K and at pH 4.7 obeys first-order kinetics. Rate constants range from 1.70 x 10(-6) (parent humic acid) to 1.06 x 10(-5) sec(-1) (derivative with maximum hydroquinone content). Stability constants for Np(V)-humic complexes calculated from spectroscopic data produce corresponding Logbeta values of 2.3 for parent humic acid and values ranging from 2.5 to 3.2 at pH 4.7 and from 3.3 to 3.7 at pH 7.4 for humic derivatives. Maximum constants are observed for hydroquinone-enriched derivatives. It is concluded that among the humic derivatives tested, the hydroquinone-enriched ones are the most useful for addressing

  13. Redox and complexation interactions of neptunium(V) with quinonoid-enriched humic derivatives

    SciTech Connect

    Shcherbina, Natalia S.; Perminova, Irina V.; Kalmykov, Stephan N.; Kovalenko, Anton N.; Novikov, Alexander P.; Haire, Richard {Dick} G

    2007-01-01

    Actinides in their higher valence states (e.g., MO{sub 2}{sup +} and MO{sub 2}{sup 2+}, where M can be Np, Pu, etc) possess a higher potential for migration and in turn pose a substantial environmental threat. To minimize this potential for migration, reducing them to lower oxidation states (e.g., their tetravalent state) can be an attractive and efficient remedial process. These lower oxidation states are often much less soluble in natural aqueous media and are, therefore, less mobile in the environment. The research presented here focuses on assessing the performance of quinonoid-enriched humic derivatives with regards to complexing and/or reducing Np(V) present in solution. These 'designer' humics are essentially derived reducing agents that can serve as reactive components of a novel humic-based remediation technology. The derivatives are obtained by incorporating different quinonoid-moieties into leonardite humic acids. Five quinonoid-derivatives are tested in this work and all five prove more effective as reducing agents for selected actinides than the parent leonardite humic acid, and the hydroquinone derivatives are better than the catechol derivatives. The reduction kinetics and the Np(V) species formed with the different derivatives are studied via a batch mode using near-infrared (NIR)-spectroscopy. Np(V) reduction by the humic derivatives under anoxic conditions at 293 K and at pH 4.7 obeys first-order kinetics. Rate constants range from 1.70 x 10{sup -6} (parent humic acid) to 1.06 x 10{sup -5} sec{sup -1} (derivative with maximum hydroquinone content). Stability constants for Np(V)-humic complexes calculated from spectroscopic data produce corresponding Log{beta} values of 2.3 for parent humic acid and values ranging from 2.5 to 3.2 at pH 4.7 and from 3.3 to 3.7 at pH 7.4 for humic derivatives. Maximum constants are observed for hydroquinone-enriched derivatives. It is concluded that among the humic derivatives tested, the hydroquinone-enriched ones

  14. Humic and fluvic acids and organic colloidal materials in the environment

    SciTech Connect

    Gaffney, J.S.; Marley, N.A.; Clark, S.B.

    1996-04-01

    Humic substances are ubiquitous in the environment, occurring in all soils, waters, and sediments of the ecosphere. Humic substances arise from the decomposition of plant and animal tissues yet are more stable than their precursors. Their size, molecular weight, elemental composition, structure, and the number and position of functional groups vary, depending on the origin and age of the material. Humic and fulvic substances have been studied extensively for more than 200 years; however, much remains unknown regarding their structure and properties. Humic substances are those organic compounds found in the environment that cannot be classified as any other chemical class of compounds. They are traditionally defined according to their solubilities. Fulvic acids are those organic materials that are soluble in water at all pH values. Humic acids are those materials that are insoluble at acidic pH values (pH < 2) but are soluble at higher pH values. Humin is the fraction of natural organic materials that is insoluble in water at all pH values. These definitions reflect the traditional methods for separating the different fractions from the original mixture. The humic content of soils varies from 0 to almost 10%. In surface waters, the humic content, expressed as dissolved organic carbon (DOC), varies from 0.1 to 50 ppm in dark-water swamps. In ocean waters, the DOC varies from 0.5 to 1.2 ppm at the surface, and the DOC in samples from deep groundwaters varies from 0.1 to 10 ppm. In addition, about 10% of the DOC in surface waters is found in suspended matter, either as organic or organically coated inorganic particulates. Humic materials function as surfactants, with the ability to bind both hydrophobic and hydrophyllic materials, making numic and fluvic materials effective agents in transporting both organic and inorganic contaminants in the environment.

  15. Humic acids as electron acceptors for anaerobic microbial oxidation of vinyl chloride and dichloroethene

    USGS Publications Warehouse

    Bradley, P.M.; Chapelle, F.H.; Lovley, D.R.

    1998-01-01

    Anaerobic oxidation of [1,2-14C]vinyl chloride and [1,2- 14C]dichloroethene to 14CO2 under humic acid-reducing conditions was demonstrated. The results indicate that waterborne contaminants can be oxidized by using humic acid compounds as electron acceptors and suggest that natural aquatic systems have a much larger capacity for contaminant oxidation than previously thought.

  16. Reduced activity of alkaline phosphatase due to host-guest interactions with humic superstructures.

    PubMed

    Mazzei, Pierluigi; Oschkinat, Hartmut; Piccolo, Alessandro

    2013-11-01

    Nuclear Magnetic Resonance (NMR) spectroscopy was applied to directly study the interactions between the alkaline phosphatase enzyme (AP) and two different humic acids from a volcanic soil (HA-V) and a Lignite deposit (HA-L). Addition of humic matter to enzyme solutions caused signals broadening in (1)H-NMR spectra, and progressive decrease and increase of enzyme relaxation (T1 and T2) and correlation (τC) times, respectively. Spectroscopic changes were explained with formation of ever larger weakly-bound humic-enzyme complexes, whose translational and rotational motion was increasingly restricted. NMR diffusion experiments also showed that the AP diffusive properties were progressively reduced with formation of large humic-enzyme complexes. The more hydrophobic HA-L affected spectral changes more than the more hydrophilic HA-V. (1)H-NMR spectra also showed the effect of progressively greater humic-enzyme complexes on the hydrolysis of an enzyme substrate, the 4-nitrophenyl phosphate disodium salt hexahydrate (p-NPP). While AP catalysis concomitantly decreased NMR signals of p-NPP and increased those of nitrophenol, addition of humic matter progressively and significantly slowed down the rate of change for these signals. In agreement with the observed spectral changes, the AP catalytic activity was more largely inhibited by HA-L than by HA-V. Contrary to previous studies, in which humic-enzyme interactions were only indirectly assumed from changes in spectrophotometric behavior of enzyme substrates, the direct measurements of AP behavior by NMR spectroscopy indicated that humic materials formed weakly-bound host-guest complexes with alkaline phosphatase, and the enzyme catalytic activity was thereby significantly inhibited. These results suggest that the role of extracellular enzymes in soils may be considerably reduced when they come in contact with organic matter dissolved in the soil solution.

  17. The Effect of Humic Substances on the Production Rate of Alkyl Nitrates in Seawater

    NASA Astrophysics Data System (ADS)

    Heiss, E. M.; Dahl, E. E.

    2008-12-01

    Alkyl nitrates are produced photochemically in seawater by the reaction of organic peroxy radicals and nitric oxide (ROO + NO). Dissolved organic matter (DOM) is a source of organic peroxy radicals in seawater, but it is unclear as to which fraction of DOM is important for alkyl nitrate formation. Dissolved humics may be important to alkyl nitrate production. The production rates of C1-C3 alkyl nitrates were observed in 0.2 μm filtered open ocean seawater as a function of nitrite concentration. The net production rates of methyl, ethyl, isopropyl, and n-propyl nitrate increased with increasing nitrite concentrations. Suwannee River humics were added to seawater samples and the net production rates of alkyl nitrates were determined. The production rate of ethyl nitrate increased at nitrite concentrations above 20 μM nitrite by a factor of ~5 with the addition of humic substances. The addition of humic substances to the water samples also resulted in an increase in the ratio of isopropyl nitrate production to ethyl nitrate production by a factor of ~3 compared to nitrite only additions. The ratio of isopropyl to ethyl nitrate production with additional humics is also greater than production rates determined using open ocean water in previous studies. The ratios of methyl nitrate and n-propyl nitrate production to ethyl nitrate production did not change significantly. The minimal change in alkyl nitrate production rates at nitrite concentrations below 20 μM indicates that NO may be the limiting reactant in this particular water sample. The effect of the humics at high nitrite concentrations shows that organic peroxy radicals are an important reactant in the production of alkyl nitrates. The difference between production rate patterns with the addition of humics compared to the nitrite only incubations indicate that humics are not the only source of organic peroxy radicals affecting open ocean water alkyl nitrate formation.

  18. The enhancement of reproduction and biodegradation activity of eukaryiotic cells by humic acids.

    PubMed

    Siglova, M; Cejkova, A; Masak, J; Jirku, V; Snajdr, J; Valina, O

    2003-01-01

    Fourteen samples of humic acids (HA) were screened for ability to influence reproduction and biodegradation activity of eukaryotic cells in the presence of chosen toxic pollutants. Microorganisms Candida maltosa and Rhodotorula mucilaginosa (soil isolates) were used for all tests. It was observed during our experiments that some samples of humic acids served as a protection against the high concentration of toxic pollutants (phenol, naphtalene etc). This effect can be widely used in many bioremediation technologies.

  19. Development of a method for the determination of naphthalene and phenanthrene in workplace air using diffusive sampling and thermal desorption GC-MS analysis.

    PubMed

    Lindahl, Roger; Claesson, Anna-Sara; Khan, Muhammad Akhtar; Levin, Jan-Olof

    2011-07-01

    Diffusive sampling methods have been validated for the determination of naphthalene and phenanthrene in workplace air. The diffusive sampler tested was the Perkin Elmer ATD tube, and the analysis was performed with thermal desorption, gas chromatography, and mass spectrometric detection. The sampling methods were validated in controlled test atmospheres, mainly according to the protocol proposed in the European standard EN 838. For the determination of naphthalene, the diffusive sampling rate was 0.41 ml min(-1) with a coefficient of variation (CV) of 19%. The mean sampling rate for phenanthrene was 0.49 ml min(-1) with a CV of 21%. Field tests confirmed the naphthalene results but could not be used to confirm the phenanthrene results. The method is not recommended for phenanthrene sampling unless the method has been tested in the specific environment and the results confirm the laboratory tests.

  20. Characterization of the International Humic Substances Society standard and reference fulvic and humic acids by solution state carbon-13 (13C) and hydrogen-1 (1H) nuclear magnetic resonance spectrometry

    USGS Publications Warehouse

    Thorn, Kevin A.; Folan, Daniel W.; MacCarthy, Patrick

    1989-01-01

    Standard and reference samples of the International Humic Substances Society have been characterized by solution state carbon-13 and hydrogen-1 nuclear magnetic resonance (NMR) spectrometry. Samples included the Suwannee River, soil, and peat standard fulvic and humic acids, the Leonardite standard humic acid, the Nordic aquatic reference fulvic and humic acids, and the Summit Hill soil reference humic acid. Aqueous-solution carbon-13 NMR analyses included the measurement of spin-lattice relaxation times, measurement of nuclear Overhauser enhancement factors, measurement of quantitative carbon distributions, recording of attached proton test spectra, and recording of spectra under nonquantitative conditions. Distortionless enhancement by polarization transfer carbon-13 NMR spectra also were recorded on the Suwannee River fulvic acid in deuterated dimethyl sulfoxide. Hydrogen-1 NMR spectra were recorded on sodium salts of the samples in deuterium oxide. The carbon aromaticities of the samples ranged from 0.24 for the Suwannee River fulvic acid to 0.58 for the Leonardite humic acid.

  1. Effects of humic acid on physical and hydrodynamic properties of kaolin flocs by particle image velocimetry.

    PubMed

    Zhong, Runsheng; Zhang, Xihui; Xiao, Feng; Li, Xiaoyan; Cai, Zhonghua

    2011-07-01

    The physical and hydrodynamic properties of kaolin flocs including floc size, strength, regrowth, fractal structure and settling velocity were investigated by in situ particle image velocimetry technique at different humic acid concentration. Jar-test experimental results showed that the adsorbed humic acid had a significant influence on the coagulation process for alum and ferric chloride. Kaolin flocs formed with the ferric chloride were larger and stronger than those for alum at same humic acid concentration. Floc strength and regrowth were estimated by strength factor and recovery factor at different humic acid concentration. It was found that the increased humic acid concentration had a slight influence on the strength of kaolin flocs and resulted in much worse floc regrowth. In addition, the floc regrowth after breakage depended on the shear history and coagulants under investigation. The changes in fractal structure recorded continuously by in situ particle image velocimetry technique during the growth-breakage-regrowth processes provided a supporting information that the kaolin flocs exhibited a multilevel structure. It was proved that the increased humic acid concentration resulted in decrease in mass fractal dimension of kaolin flocs and consequently worse sedimentation performance through free-settling and microbalance techniques.

  2. Direct solid surface fluorescence spectroscopy of standard chemicals and humic acid in ternary system.

    PubMed

    Mounier, S; Nicolodelli, G; Redon, R; Milori, D M B P

    2017-04-15

    The front face fluorescence spectroscopy is often used to quantify chemicals in well-known matrices as it is a rapid and powerful technique, with no sample preparation. However it was not used to investigate extracted organic matter like humic substances. This work aims to fully investigate for the first time front face fluorescence spectroscopy response of a ternary system including boric acid, tryptophan and humic substances, and two binaries system containing quinine sulfate or humic substance in boric acid. Pure chemicals, boric acid, tryptophan, quinine sulfate and humic acid were mixed together in solid pellet at different contents from 0 to 100% in mass. The measurement of excitation emission matrix of fluorescence (3D fluorescence) and laser induced fluorescence were then done in the front face mode. Fluorescence matrices were decomposed using the CP/PARAFAC tools after scattering treatments. Results show that for 3D fluorescence there is no specific component for tryptophan and quinine sulfate, and that humic substances lead to a strong extinction effect for mixture containing quinine sulfate. Laser induced fluorescence gives a very good but non-specific related response for both quinine sulfate and tryptophan. No humic substances fluorescence response was found, but extinction effect is observed as for 3D fluorescence. This effect is stronger for quinine sulfate than for tryptophan. These responses were modeled using a simple absorbance versus emission model.

  3. Complexation of transuranic ions by humic substances: Application of laboratory results to the natural system

    SciTech Connect

    Czerwinski, K.; Kim, J.

    1997-12-31

    Environmental investigations show transuranic ions sorb to humic substances. The resulting species are often mobile and are expected to be important vectors in the migration of transuranic ions in natural systems. However, these environmental studies yield no quantitative data useful for modeling. Laboratory complexation experiments with transuranic ions and humic substances generate thermodynamic data required for complexation modeling. The data presented in this work are based on the metal ion charge neutralization model, which is briefly described. When a consistent complexation model is used, similar results are obtained from different experimental conditions, techniques, and laboratories. Trivalent transuranic ions (Cm(III), Am(III)) have been extensively studied with respect to pH, ionic strength, origin of humic acid, and mixed species formation. The complexation of Np(V) has been examined over a large pH and metal ion concentration range with different humic acids. Some data does exist on the complexation ion concentration range with different humic acids. Some data does exist on the complexation of plutonium with humic acid, however further work is needed. Calculations on the Gorleben aquifer system using the thermodynamic data are presented. Critical information lacking from the thermodynamic database is identified. 55 refs., 2 figs., 3 tabs.

  4. Removal of humic substances from water by means of calcium-ion-enriched natural zeolites.

    PubMed

    Capasso, S; Colella, C; Coppola, E; Iovino, P; Salvestrini, S

    2007-03-01

    The ability of the natural zeolited Neapolitan Yellow Tuff (NYT) enriched with calcium ions to remove humic acids from water was evaluated by batch adsorption equilibrium tests and dynamic experiments carried out by percolating humic acid solutions through a small NYT column (breakthrough curves). Under the experimental condition explored, the sorption capacity increases with the ionic strength and has the highest value at pH 7.4. The partition coefficient for a low concentration of humic acid ([humic acid] --> 0), at pH 7.4 in 0.01 M sodium chloride, was approximately 1000 L/kg, versus the value of approximately 100 L/kg in the absence of the alkaline metal salt. Therefore, after humic acids have been adsorbed in a column filled with the calcium-ion-enriched tuff, a reduction of the salt concentration in the ongoing solution enhances the release of the adsorbed material. These findings show that NYT can be used for the removal of humic acids from water.

  5. Influence of humic acid on the uptake of aqueous metals by the killifish Fundulus heteroclitus.

    PubMed

    Dutton, Jessica; Fisher, Nicholas S

    2012-10-01

    The role of humic acids, over a concentration range of 0 to 20 mg L(-1) , was investigated in the uptake of three metals (Cd, Cr, and Hg-as both inorganic Hg [Hg(II)] and methylmercury [MeHg]) and a metalloid (As) from the aqueous phase by the killifish (Fundulus heteroclitus). Cadmium uptake showed no relationship with humic acid concentration, whereas Cr, Hg(II), and MeHg uptake showed an inverse relationship, and As uptake increased with increasing humic acid concentration. Concentration factors were >1 for Cd, Hg(II), and MeHg at all humic acid concentrations, indicating killifish were more enriched in the metal than the experimental media, whereas As and Cr generally had concentration factors <1 at the end of a 72-h exposure. The uptake of As and Cr reached steady state within the 72-h exposure, whereas uptake of Cd, Hg(II), and MeHg did not. Uptake rate constants (k(u) s; ml g(-1)  d(-1) ) were highest for MeHg (91-3,936), followed by Hg(II), Cd, and Cr, and lowest for As (0.17-0.29). Dissection data revealed that the gills generally had the highest concentration of all metals under all humic acid treatments. The present study concludes that changes in humic acid concentration can influence the accumulation of aqueous metals in killifish and should be considered when modeling metal bioaccumulation.

  6. Characterization of the interaction of uranyl ions with humic acids by x-ray absorption spectroscopy

    SciTech Connect

    Reich, T.; Denecke, M.A.; Pompe, S.

    1995-11-01

    Humic substances are present throughout the environment in soil and natural water. They are organic macromolecules with a variable structural formula, molecular weight, and a wide variety of functional groups depending on their origin. In natural waters, humic substances represent the main component of the {open_quotes}dissolved organic carbon{close_quotes} (DOC). The DOC may vary considerably from 1 mg/L at sea water surfaces to 50 mg/L at the surface in dark water swamps. There is strong evidence that all actinides form complexes with humic substances in natural waters. Therefore, humic substances can play an important role in the environmental migration of radionuclides by enhancing their transport. Retardation through humic substance interaction may be also possible due to formation of precipitating agglomerates. For remediation and restoration of contaminated environmental sites and risk assessment of future nuclear waste repositories, it is important to improve the predictive capabilities for radionuclide migration through a better understanding of the interaction of radionuclides with humic substances.

  7. Enhanced adsorption of humic acids on ordered mesoporous carbon compared with microporous activated carbon.

    PubMed

    Liu, Fengling; Xu, Zhaoyi; Wan, Haiqin; Wan, Yuqiu; Zheng, Shourong; Zhu, Dongqiang

    2011-04-01

    Humic acids are ubiquitous in surface and underground waters and may pose potential risk to human health when present in drinking water sources. In this study, ordered mesoporous carbon was synthesized by means of a hard template method and further characterized by X-ray diffraction, N2 adsorption, transition electron microscopy, elemental analysis, and zeta-potential measurement. Batch experiments were conducted to evaluate adsorption of two humic acids from coal and soil, respectively, on the synthesized carbon. For comparison, a commercial microporous activated carbon and nonporous graphite were included as additional adsorbents; moreover, phenol was adopted as a small probe adsorbate. Pore size distribution characterization showed that the synthesized carbon had ordered mesoporous structure, whereas the activated carbon was composed mainly of micropores with a much broader pore size distribution. Accordingly, adsorption of the two humic acids was substantially lower on the activated carbon than on the synthesized carbon, because of the size-exclusion effect. In contrast, the synthesized carbon and activated carbon showed comparable adsorption for phenol when the size-exclusion effect was not in operation. Additionally, we verified by size-exclusion chromatography studies that the synthesized carbon exhibited greater adsorption for the large humic acid fraction than the activated carbon. The pH dependence of adsorption on the three carbonaceous adsorbents was also compared between the two test humic acids. The findings highlight the potential of using ordered mesoporous carbon as a superior adsorbent for the removal of humic acids.

  8. Reconnaissance samplings and characterization of aquatic humic substances at the Yuma Desalting Test Facility, Arizona

    USGS Publications Warehouse

    Malcolm, R.L.; Wershaw, R. L.; Thurman, E.M.; Aiken, G.R.; Pinckney, D.J.; Kaakinen, J.

    1981-01-01

    Smectite clay minerals were found to be the principal compound on the surface of the cellulose-acetate, reverse-osmosis membranes at the Yuma Desalting Test Facility. These clay minerals were not present in the pumped ground water, but were blown into the conveyance canal from adjacent soils. Humic substances from the water and suspended sediments were associated with the clay films on the membrane, but no definitive results concerning their role in fouling were achieved. Microbial fouling is believed to be only a minor aspect of membrane fouling. Chemical and physical changes in humic substances were extensively studied at four points in the water-treatment process. Humic substances accounted for the largest component (over 25 percent) of organic constituents. Humic substances in the canal source water were similar to other aquatic humic substances present in natural waters. During the treatment process, these substances are brominated and decolorized. The effect of these halogenated humic substances on membrane fouling is unclear, but their presence in the reverse-osmosis product water and reverse-osmosis reject brine, along with volatile trihalomethanes, has led to environmental concerns. (USGS)

  9. Bioactivity of chemically transformed humic matter from vermicompost on plant root growth.

    PubMed

    Dobbss, Leonardo Barros; Pasqualoto Canellas, Luciano; Lopes Olivares, Fábio; Oliveira Aguiar, Natália; Peres, Lázaro Eustáquio Pereira; Azevedo, Mariana; Spaccini, Riccardo; Piccolo, Alessandro; Façanha, Arnoldo R

    2010-03-24

    Chemical reactions (hydrolysis, oxidation, reduction, methylation, alkyl compounds detachment) were applied to modify the structure of humic substances (HS) isolated from vermicompost. Structural and conformational changes of these humic derivatives were assessed by elemental analyses, size exclusion chromatography (HPSEC), solid-state nuclear magnetic resonance ((13)C CPMAS-NMR), and diffusion ordered spectroscopy (DOSY-NMR), whereas their bioactivity was evaluated by changes in root architecture and proton pump activation of tomato and maize. All humic derivatives exhibited a large bioactivity compared to original HS, both KMnO(4)-oxidized and methylated materials being the most effective. Whereas no general relationship was found between bioactivity and humic molecular sizes, the hydrophobicity index was significantly related with proton pump stimulation. It is suggested that the hydrophobic domain can preserve bioactive molecules such as auxins in the humic matter. In contact with root-exuded organic acids the hydrophobic weak forces could be disrupted, releasing bioactive compounds from humic aggregates. These findings were further supported by the fact that HS and all derivatives used in this study activated the auxin synthetic reporter DR5::GUS.

  10. Separation of humic acids from Bayer process liquor by membrane filtration

    SciTech Connect

    Awadalla, F.T.; Kutowy, O.; Tweddle, A. ); Hazlett, J.D. )

    1994-05-01

    Humic acids of high molecular weight were removed from spent Bayer liquor by polymeric ultrafiltration membranes. Among the commercial and laboratory-cast membranes tested, Radel-R polyphenylsulfone on a polypropylene backing material was found to be the most promising candidate for this separation. However, the maximum separation of humic acids obtained at operating conditions of 50[degree]C and 0.34 MPa, as measured by spectrophotometric analysis, was only in the 50 to 55% range. In order to explain this limited membrane separation of humic acids in spent Bayer liquor, a synthetic alkaline solution of humic acids was treated using the same membranes. These tests indicated much higher separation of humic acids (92%). Humic substances in Bayer liquor appear to be hydrolyzed and degraded to low molecular weight fractions (molecular weight < 1000 daltons) by the combined action of the strongly alkaline Bayer liquor and high digestion temperatures. These low molecular weight fractions cannot be retained by standard ultrafiltration membranes. However, some preliminary tests with laboratory-cast Radel-R nanofiltration membranes showed improved color separation (> 70%) when treating spent Bayer liquor. 23 refs., 8 figs., 5 tabs.

  11. Direct solid surface fluorescence spectroscopy of standard chemicals and humic acid in ternary system

    NASA Astrophysics Data System (ADS)

    Mounier, S.; Nicolodelli, G.; Redon, R.; Milori, D. M. B. P.

    2017-04-01

    The front face fluorescence spectroscopy is often used to quantify chemicals in well-known matrices as it is a rapid and powerful technique, with no sample preparation. However it was not used to investigate extracted organic matter like humic substances. This work aims to fully investigate for the first time front face fluorescence spectroscopy response of a ternary system including boric acid, tryptophan and humic substances, and two binaries system containing quinine sulfate or humic substance in boric acid. Pure chemicals, boric acid, tryptophan, quinine sulfate and humic acid were mixed together in solid pellet at different contents from 0 to 100% in mass. The measurement of excitation emission matrix of fluorescence (3D fluorescence) and laser induced fluorescence were then done in the front face mode. Fluorescence matrices were decomposed using the CP/PARAFAC tools after scattering treatments. Results show that for 3D fluorescence there is no specific component for tryptophan and quinine sulfate, and that humic substances lead to a strong extinction effect for mixture containing quinine sulfate. Laser induced fluorescence gives a very good but non-specific related response for both quinine sulfate and tryptophan. No humic substances fluorescence response was found, but extinction effect is observed as for 3D fluorescence. This effect is stronger for quinine sulfate than for tryptophan. These responses were modeled using a simple absorbance versus emission model.

  12. Combined remediation of Cd-phenanthrene co-contaminated soil by Pleurotus cornucopiae and Bacillus thuringiensis FQ1 and the antioxidant responses in Pleurotus cornucopiae.

    PubMed

    Jiang, Juan; Liu, Hongying; Li, Qiao; Gao, Ni; Yao, Yuan; Xu, Heng

    2015-10-01

    Remediation of soil co-contaminated with heavy metals and PAHs by mushroom and bacteria is a novel technique. In this study, the combined remediation effect of mushroom (Pleurotus cornucopiae) and bacteria (FQ1, Bacillus thuringiensis) on Cd and phenanthrene co-contaminated soil was investigated. The effect of bacteria (B. thuringiensis) on mushroom growth, Cd accumulation, phenanthrene degradation by P. cornucopiae and antioxidative responses of P. cornucopiae were studied. P. cornucopiae could adapt easily and grow well in Cd-phenanthrene co-contaminated soil. It was found that inoculation of FQ1 enhanced mushroom growth (biomass) and Cd accumulation with the increment of 26.68-43.58% and 14.29-97.67% respectively. Up to 100% and 95.07% of phenanthrene were removed in the bacteria-mushroom (B+M) treatment respectively spiked with 200mg/kg and 500mg/kg phenanthrene. In addition, bacterial inoculation alleviated oxidative stress caused by co-contamination with relative decreases in lipid peroxidation and enzyme activity, including malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD). This study demonstrated that the integrated remediation strategy of bacteria and mushroom is an effective and promising method for Cd-phenanthrene co-contaminated soil bioremediation.

  13. Investigating the foliar uptake and within-leaf migration of phenanthrene by moss (Hypnum cupressiforme) using two-photon excitation microscopy with autofluorescence.

    PubMed

    Keyte, Ian; Wild, Edward; Dent, John; Jones, Kevin C

    2009-08-01

    Mosses have the potential to play a significant role in the global cycling and fate of semivolatile organic compounds (SVOCs), due to their extensive distribution at high latitudes and the long-range atmospheric transport of SVOCs. Unlike vascular plants mosses lack a substantial cuticle, vascular system, or root structure, taking up water, nutrients and SVOCs primarily from the atmosphere. Mosses have thus been effectively used as passive air samplers for many SVOCs in urban and rural locations. The potential differences in atmospheric uptake and within-leaf movement storage and processing of SVOCs between vascular and nonvascular living plants were investigated here by comparing the uptake and behavior of phenanthrene in spinach (Spinacia oleracea) and moss (Hypnum cupressiforme), using two-photon excitation microscopy coupled with autofluorescence. Chemical uptake, movement storage, and compartmentalization of phenanthrene was directly detected, visualized, and monitored over a 12 day period following exposure to gas phase phenanthrene. Species differences in the uptake of phenanthrene between moss and spinach leaves were observed, showing how morphological differences affect the foliar uptake of SVOCs. In spinach, phenanthrene accumulated within the cellular cytoplasm and vacuole. In moss, phenanthrene accumulated predominantly within the cell walls, before later migrating across the cell membrane into adjacent cells and the cellular cytoplasm. The study represents a further demonstration of how different plant species can display different and complex transport and storage pathways for the same chemical, and highlights the importance of the cellular structure and plant morphological and physiological features in controlling this behavior.

  14. Investigation of the Effect of Humic Acids on Phototransformation of Naphthalene Illuminated by Visible and UV Light

    NASA Astrophysics Data System (ADS)

    Nechaev, L. V.; Tchaikovskaya, O. N.

    2016-04-01

    Results of investigation of the effect of humic acids on the degree of photochemical transformation of naphthalene in an aqueous solution illuminated by model solar and UV light are presented. The constant of complexation of naphthalene and humic acids is determined. It is established that the molecular complex of the humic acid and naphthalene is more stable to illumination by UV light then by model sunlight.

  15. Influence of humic acid on the toxicity of copper, cadmium and lead to the unicellular alga, Synechosystis aquatilis

    SciTech Connect

    Shanmukhappa, H.; Neelakantan, K. )

    1990-06-01

    Humic acids are known to play a significant role in phytoplankton productivity by regulating the trace metals required for plant growth. Although few attempts have been made to evaluate the influence of humic acids on heavy metal toxicity to aquatic organisms, their interaction in natural waters is well documented. The present study was undertaken to evaluate the influence of humic acids (HA) extracted from mangrove sediments on Cu, Cd and Pb toxicity to the unicellular alga, Synechosystis aquatilis.

  16. Synthetic humic substances and their use for remediation of contaminated environments

    NASA Astrophysics Data System (ADS)

    Dudare, Diana; Klavins, Maris

    2014-05-01

    Soils are increasingly subjected to different chemical stresses, because of increasing industrialization process and other factors. Different anthropogenic compounds (organic or inorganic in nature) upon entering the soil, may not only influence its productivity potential, but may also affect the quality of groundwater and food chain. Consequently, soils of different environments contain a complex mixture of contaminants, such as oil products, metals, organic solvents, acids, bases and radionuclides. Thereby greater focus should be paid to risk assessment and evaluation of remedial techniques in order to restore the quality of the soil and groundwater. The treatment technologies presently used to remove contaminants are physical, chemical and biological technologies. Many functional groups in the structure of humic substances determine their ability to interact with metal ions forming stable complexes and influencing speciation of metal ions in the environment, as well mobility, behaviour and speciation forms in the environment. Humic substances are suggested for use in the remediation of environments contaminated with metals, owing to complex forming properties. Several efforts have been undertaken with respect to synthesize humic substances for their structural studies. At the same time the real number of methods suggested for synthesis of humic substances is highly limited and their synthesis in general has been used mostly for their structural analysis. The present study deals with development of approaches for synthesis of humic substances with increased complex forming ability in respect to metal ions. Industrially produced humic substances (TEHUM) were used for comparison and after their modification their properties were analyzed for their elemental composition; functional group content changes in spectral characteristics. Synthetic humic substances showed significant differences in the number of functional groups and in ability to interact with the metal

  17. Adsorption of carbamazepine by carbon nanotubes: effects of DOM introduction and competition with phenanthrene and bisphenol A.

    PubMed

    Lerman, Ilya; Chen, Yona; Xing, Baoshan; Chefetz, Benny

    2013-11-01

    Carbon nanotubes, organic contaminants and dissolved organic matter (DOM) are co-introduced into the environment. Thus, the interactions between these components have to be evaluated to better understand their environmental behavior. In this study, single-walled carbon nanotubes (SWCNTs) were used as sorbent, carbamazepine was the primary adsorbate, and bisphenol A and phenanthrene were used as competitors. Strong competition with bisphenol A and no effect of phenanthrene on adsorption of carbamazepine was obtained. The hydrophobic neutral fraction of the DOM exhibited the strongest reductive effect on carbamazepine adsorption, most probably due to interactions in solution. In contrast, the hydrophobic acid fraction decreased carbamazepine adsorption mainly via direct competition. When DOM and bisphenol A were co-introduced, the adsorption of carbamazepine was significantly reduced. This study suggests that the chemical nature of DOM can significantly affect the sorptive behavior of polar organic pollutants with carbon nanotubes when all are introduced to the aquatic system.

  18. New diagnostic ratios based on phenanthrenes and anthracenes for effective distinguishing heavy fuel oils from crude oils.

    PubMed

    Zhang, Haijiang; Wang, Chuanyuan; Zhao, Ruxiang; Yin, Xiaonan; Zhou, Hongyang; Tan, Liju; Wang, Jiangtao

    2016-05-15

    The heavy fuel oils (HFOs) and crude oils are the main oil types in the marine oil spill accidents in China. It is usually a challenge to distinguish the HFOs from crude oils due to the highly similar physicochemical characteristics. In this paper, the distributions of phenanthrene (Phe), anthracene (Ant), methyl-phenanthrene (MP) and methyl-anthracene (MA) in hundreds of HFOs and crude oils samples which were collected from all over the world were characterized. Nine new diagnostic indexes, such as Ant/(Ant+Phe) and other eight diagnostic ratios based on the MP isomers and MA, were developed for effective distinguishing HFOs from crude oils. The histogram with normal fit plots, the double ratio plots and Bayes discriminant analysis (BDA) method were employed to illustrate the effectiveness of the new diagnostic indexes. BDA model based on nine new diagnostic indexes demonstrated high precision with discriminant ratio which lay between 93.92% and 99.32%.

  19. Removal and Biodegradation of Phenanthrene, Fluoranthene and Pyrene by the Marine Algae Rhodomonas baltica Enriched from North Atlantic Coasts.

    PubMed

    Arias, Andrés H; Souissi, Anissa; Glippa, Olivier; Roussin, Marion; Dumoulin, David; Net, Sopheak; Ouddane, Baghdad; Souissi, Sami

    2017-03-01

    This study is focused on the removal, accumulation and degradation of three environmental ubiquitous polycyclic aromatic hydrocarbons (PAHs), phenanthrene (PHE), fluoranthene (FLA) and pyrene (PYR), by the marine alga Rhodomonas baltica enriched from the English Channel. After separation, purification and culture in several phases, R. baltica was exposed to PAH concentrations that are frequently encountered in the field in several anthropized environments. The results showed that R. baltica can grow under PAH stress, efficiently remove up to 70% of these compounds from the medium by 216 h of culture and selectively bioaccumulate PAHs by their hydrophobicity. Between PHE, FLA and PYR, phenanthrene was the compound with higher degradation rates throughout incubation. The equilibrium partitioning theoretical approach showed that physico-chemical partitioning, rather than active bioconcentration, was the major factor governing the bioaccumulation, outlying a potential application in decontamination processes for this species.

  20. Synthesis and characterization of agricultural controllable humic acid superabsorbent.

    PubMed

    Gao, Lijuan; Wang, Shiqiang; Zhao, Xuefei

    2013-12-01

    Humic acid superabsorbent polymer (P(AA/AM-HA)) and superabsorbent polymer (P(AA/AM)) were synthesized by aqueous solution polymerization method using acrylic acid (AA), acrylamide (AM) and humic acid (HA) as raw material. The effects of N,N'-methylenebisacrylamide (MBA) crosslinking agent, potassium peroxydisulfate (KPS) initiator, reaction temperature, HA content, ratio of AA to AM, concentration of monomer and neutralization of AA on water absorption were investigated. Absorption and desorption ratios of nitrogen fertilizer and phosphate fertilizer were also investigated by determination of absorption and desorption ratio of NH4(+), PO4(3-) on P(AA/AM-HA) and P(AA/AM). The P(AA/AM-HA) and P(AA/AM) were characterized by Fourier translation infrared spectroscopy, biological photomicroscope and scanning electron microscopy (SEM). The optimal conditions obtained were as follows: the weight ratio of MBA to AA and AM was 0.003; the weight ratio of KPS to AA and AM was 0.008; the weight ratio of HA to AA was 0.1; the mole ratio of AM to AA is 0.1; the mole ratio of NaOH to AA is 0.9; the reaction temperature was 60°C. P(AA/AM-HA) synthesized under optimal conditions, has a good saline tolerance, its water absorbency in distilled water and 0.9 wt.% saline solution is 1180 g/g and 110 g/g, respectively. P(AA/AM-HA) achieves half saturation in 6.5 min. P(AA/AM-HA) is superior to P(AA/AM) on absorption of NH4(+), PO4(3-). The SEM micrograph of P(AA/AM-HA) shows a fine alveolate structure. The biological optical microscope micrograph of P(AA/AM-HA) shows a network structure. Graft polymerization between P(AA/AM) and HA was demonstrated by infrared spectrum. The P(AA/AM-HA) superabsorbent has better absorbing ability of water and fertilizer, electrolytic tolerance and fewer cost than P(AA/AM) superabsorbent.

  1. River-derived humic substances as iron chelators in seawater

    PubMed Central

    Krachler, Regina; Krachler, Rudolf F.; Wallner, Gabriele; Hann, Stephan; Laux, Monika; Cervantes Recalde, Maria F.; Jirsa, Franz; Neubauer, Elisabeth; von der Kammer, Frank; Hofmann, Thilo; Keppler, Bernhard K.

    2015-01-01

    The speciation of iron(III) in oxic seawater is dominated by its hydrolysis and sedimentation of insoluble iron(III)-oxyhydroxide. As a consequence, many oceanic areas have very low iron levels in surface seawater which leads to iron deficiency since phytoplankton require iron as a micronutrient in order to grow. Fortunately, iron solubility is not truly as low as Fe(III) solubility measurements in inorganic seawater would suggest, since oceanic waters contain organic molecules which tend to bind the iron and keep it in solution. Various iron-binding organic ligands which combine to stabilize dissolved iron have been detected and thoroughly investigated in recent years. However, the role of iron-binding ligands from terrestrial sources remains poorly constrained. Blackwater rivers supply large amounts of natural organic material (NOM) to the ocean. This NOM (which consists mainly of vascular plant-derived humic substances) is able to greatly enhance iron bioavailability in estuaries and coastal regions, however, breakdown processes lead to a rapid decrease of river-derived NOM concentrations with increasing distance from land. It has therefore been argued that the influence of river-derived NOM on iron biogeochemistry in offshore seawater does not seem to be significant. Here we used a standard method based on 59Fe as a radiotracer to study the solubility of Fe(III)-oxyhydroxide in seawater in the presence of riverine NOM. We aimed to address the question how effective is freshwater NOM as an iron chelator under open ocean conditions where the concentration of land-derived organic material is about 3 orders of magnitude smaller than in coastal regions, and does this iron chelating ability vary between NOM from different sources and between different size fractions of the river-borne NOM. Our results show that the investigated NOM fractions were able to substantially enhance Fe(III)-oxyhydroxide solubility in seawater at concentrations of the NOM ≥ 5

  2. Plant-accelerated dissipation of phenanthrene and pyrene from water in the presence of a nonionic-surfactant.

    PubMed

    Gao, Yanzheng; Ling, Wanting; Wong, Ming H

    2006-06-01

    Plant-accelerated dissipation of phenanthrene and pyrene in water in the presence of a nonionic-surfactant (Brij35) was studied. The mechanisms involved were evaluated, based on the investigation of plant uptake of these compounds from water with Brij35. The presence of ryegrass (Lolium multiflorum Lam) clearly enhanced the dissipation of tested PAHs in water with 0-296 mg l(-1) Brij35. The first-order rate constants (K), calculated from the first-order kinetic models for these PAH degradation (all significant at P < 0.05, n=8), of phenanthrene and pyrene in the presence of ryegrass were 16.7-50% and 47.1-108% larger than those of plant-free treatments, whereas half-lives (T1/2) of the former were 14.3-33.4% and 32.0-52.0% smaller than the latter, respectively. However, the promotion of PAH dissipation by ryegrass was found to significantly decrease with increasing Brij35 concentrations. In the range of 0-296 mg l(-1), low concentrations (< or = 74.0 mg l(-1)) of Brij35 generally enhanced plant uptake and accumulation of phenanthrene and pyrene, based on the observed plant concentrations and accumulated amounts of these chemicals from water. In contrast, Brij35 at relatively high concentrations (> or = 148 mg l(-1)) markedly restricted plant uptake of these PAHs. Plant accumulation of phenanthrene and pyrene accounted for 6.21-35.0% and 7.66-24.3% of the dissipation enhancement of these compounds from planted versus unplanted water bodies. In addition, plant metabolism was speculated to be another major mechanism of plant-accelerated dissipation of these PAHs in water systems. Results obtained from this study provided some insight with regard to the feasibility of phytoremediation for PAH contaminated water bodies with coexisted contaminants of surfactants.

  3. Effects of nonionic surfactants on the microbial mineralization of phenanthrene in soil-water systems. [Quarterly report

    SciTech Connect

    Laha, S.; Luthy, R.G.

    1992-05-01

    The purpose of the work reported in this paper was to determine whether the inhibitory effect on microbial degradation of phenanthrene was specific to the nonionic surfactants used previously, i.e., the alkylethoxylate and alkylphenol ethoxylate surfactants. Thus, a number of nonionic surfactants of varying structures and properties were selected for further investigation. In addition, several tests were performed to verify results from earlier experiments.

  4. Transcriptional responses indicate attenuated oxidative stress in the springtail Folsomia candida exposed to mixtures of cadmium and phenanthrene.

    PubMed

    de Boer, Muriel E; Ellers, Jacintha; van Gestel, Cornelis A M; den Dunnen, Johan T; van Straalen, Nico M; Roelofs, Dick

    2013-05-01

    Since the 'omics revolution', the assessment of toxic chemical mixtures has incorporated approaches where phenotypic endpoints are connected to a mechanistic understanding of toxicity. In this study we determined the effect of binary mixtures of cadmium and phenanthrene on the reproduction of Folsomia candida and investigated the cellular mechanisms underlying this response. Mixture toxicity modeling showed an antagonistic deviation from concentration addition for reproduction effects of the mixtures. Subsequent transcriptional response analysis was done using five mixtures at the modeled 50 % effect level for reproduction. The transcription profiles of 86 high throughput RT-qPCR assays were studied by means of partial least squares regression analysis. The first and second principal components (PCs) were correlated with global responses to cadmium and phenanthrene, while correlations with the mixture treatments were found in the higher PCs. Specifically associated with the mixture treatments were a biotransformation phase II gene, four mitochondrial related genes and a gene involved in the biosynthesis of antioxidant selenoproteins. Membrane integrity related gene inductions were correlated with the single phenanthrene treatment but not with the mixtures. Immune and inflammatory response assays did not correlate with any of the mixtures. These results suggest moderated oxidative stress, a higher mitochondrial maintenance and less compromised membrane function in the mixture exposed samples compared to the separate cadmium or phenanthrene exposures. The antagonism found for inhibition of reproduction may partially originate from these differences. Mechanistic studies on mixture toxicity can ultimately aid risk assessment by defining relevant toxicity pathways in organisms exposed to real-world mixture exposures present in the field.

  5. Thermal-delayed fluorescence of pyromellitic dianhydride—anthracene trap in charge-transfer pyromellitic dianhyride—phenanthrene host crystal

    NASA Astrophysics Data System (ADS)

    Kozankiewicz, B.

    1990-10-01

    The fluorescence, phosphorescence and delayed fluorescence in an anthracene-doped pyromellitic dianhydride—phenanthrene crystal is studied within the temperature range 200-330 K. The dominating long-lived emission for temperatures above 250 K is thermal-delayed fluorescence, originating from the singlet trap created by thermal promotion of the triplet trap. The trap is formed on the pyromellitic dianhydride—anthracene complex unit. The activation energy of thermal promotions is ≈ 2500 cm -1.

  6. Enhancing plant-microbe associated bioremediation of phenanthrene and pyrene contaminated soil by SDBS-Tween 80 mixed surfactants.

    PubMed

    Ni, Hewei; Zhou, Wenjun; Zhu, Lizhong

    2014-05-01

    The use of surfactants to enhance plant-microbe associated dissipation in soils contaminated with polycyclic aromatic hydrocarbons (PAHs) is a promising bioremediation technology. This comparative study was conducted on the effects of plant-microbe treatment on the removal of phenanthrene and pyrene from contaminated soil, in the presence of low concentration single anionic, nonionic and anionic-nonionic mixed surfactants. Sodium dodecyl benzene sulfonate (SDBS) and Tween 80 were chosen as representative anionic and nonionic surfactants, respectively. We found that mixed surfactants with concentrations less than 150 mg/kg were more effective in promoting plant-microbe associated bioremediation than the same amount of single surfactants. Only about (m/m) of mixed surfactants was needed to remove the same amount of phenanthrene and pyrene from either the planted or unplanted soils, when compared to Tween 80. Mixed surfactants (< 150 mg/kg) better enhanced the degradation efficiency of phenanthrene and pyrene via microbe or plant-microbe routes in the soils. In the concentration range of 60-150 mg/kg, both ryegrass roots and shoots could accumulate 2-3 times the phenanthrene and pyrene with mixed surfactants than with Tween 80. These results may be explained by the lower sorption loss and reduced interfacial tension of mixed surfactants relative to Tween 80, which enhanced the bioavailability of PAHs in soil and the microbial degradation efficiency. The higher remediation efficiency of low dosage SDBS-Tween 80 mixed surfactants thus advanced the technology of surfactant-enhanced plant-microbe associated bioremediation.

  7. Effect of freeze-thawing cycles on aging behavior of phenanthrene, pyrene and their mixture in soil.

    PubMed

    Zhao, Qing; Xing, Baoshan; Tai, Peidong; Yang, Kun; Li, Hong; Zhang, Lizhu; Lin, Gao; Li, Peijun

    2013-05-01

    This work was initiated to study the competitive sorption effect on phenanthrene and pyrene extraction during the aging process in phaeozem, burozem, aquorizem and krasnozem with or without freeze-thawing cycles. Soils contaminated with 100 μg g(-1) phenanthrene and 100 μg g(-1) pyrene separately and combined were extracted by 10 g L(-1) surfactant SDBS solution at various times over 120 days. The competitive effect on extraction efficiency may either increase or decrease with increasing soil contact time, depending on the properties of the accessible adsorption sites. The increased difference in extraction efficiency change has a positive correlation with soil organic carbon content. The change in extraction efficiency between no freeze-thawing and freeze-thawing in soils contaminated with both hydrocarbons was smaller compared to it with phenanthrene or pyrene alone due to the similar roles freeze-thawing and competitive effect plays, causing contaminant molecules to occupy the high-energy adsorption sites and expanding the glassy domain of soil organic matter. No general conclusions were obtained among the frequency of freeze-thawing cycles, soil moisture and extraction efficiency. This study validates our previous conceptual freeze-thawing model and is expected to help the development of the environmental fate and risk assessment.

  8. [Influence of Three Low-Molecular-Weight Organic Acids on the Adsorption of Phenanthrene in Purple Soil].

    PubMed

    Xie, Li; Chen, Ben-shou; Zhang, Jin-zhong; Lu, Song; Jiang, Tao

    2016-03-15

    The effects of three low-molecular-weight organic acids (citric acid, malic acid and oxalic acid) on the adsorption of phenanthrene in purple soil were studied by static adsorption experiment. The results showed that the adsorption kinetic process of phenanthrene in purple soil could be described by the second-order kinetic model, and the adsorption rate constant would significantly decrease in the presence of the three low-molecular-weight organic acids ( LMWOAs). The adsorption thermodynamic process could be well described by linear adsorption model, which was dominated by distribution role. The three LMWOAs could promote the adsorption of phenantherene in purple soil when their concentrations were less than 5 mmol · L⁻¹, whereas inhibit the adsorption when their concentrations were more than 10 mmol · L⁻¹, and the inhibition would increase with increasing concentrations. Moreover, the inhibitory ability displayed a decreasing order of citric acid, oxalic acid, and malic acid when their concentrations were 20 mmol · L⁻¹, which is related to the molecular structure and acidity of the three LMWOAs. Compared with the control, the content of dissolved organic matter (DOM) released from purple soil showed a trend of first decrease and then increase with increasing LMWOAs concentration, and the adsorption capacity of phenanthrene in purple soil was negatively related to DOM content.

  9. Simultaneous control of phenanthrene and drought by dual exposure system: the degree of synergistic interactions in springtails was exposure dependent.

    PubMed

    Schmidt, Stine N; Holmstrup, Martin; Damgaard, Christian; Mayer, Philipp

    2014-08-19

    Organisms in the environment are exposed to multiple stressors. However, for terrestrial invertebrates, it remains difficult to study the effects of combined stressors under well-defined exposure conditions. Thus, the current study develops a new dual exposure system for the simultaneous and independent control of chemical and drought exposure in bioassays with terrestrial organisms: Passive dosing from silicone controlled the chemical activity of phenanthrene (chemical stress), while saline solutions controlled the water activity (drought stress) in the closed exposure system. The dual exposure system was then applied in a full factorial experiment with seven exposure levels (7(2)), which aimed at determining the combined effects of phenanthrene and drought on the survival of the terrestrial springtail Folsomia candida after 7 d exposure. Fitting an "independent action" model to the complete data set revealed statistically significant synergy between phenanthrene and drought (p < 0.0001). However, the degree of synergy was exposure dependent with some synergy at higher and only minor synergy at lower exposure levels. This emphasizes the need for taking exposure levels into account when extrapolating synergy observations from (eco)toxicological studies done at high exposure levels.

  10. Humic substances interfere with phosphate removal by Lanthanum modified clay in controlling eutrophication.

    PubMed

    Lürling, Miquel; Waajen, Guido; van Oosterhout, Frank

    2014-05-01

    The lanthanum (La) modified bentonite Phoslock(®) has been proposed as dephosphatisation technique aiming at removing Filterable Reactive Phosphorus (FRP) from the water and blocking the release of FRP from the sediment. In the modified clay La is expected the active ingredient. We conducted controlled laboratory experiments to measure the FRP removal by Phoslock(®) in the presence and absence of humic substances, as La complexation with humic substances might lower the effectiveness of La (Phoslock(®)) to bind FRP. The results of our study support the hypothesis that the presence of humic substances can interfere with the FRP removal by the La-modified bentonite. Both a short-term (1 d) and long-term (42 d) experiment were in agreement with predictions derived from chemical equilibrium modelling and showed lower FRP removal in presence of humic substances. This implies that in DOC-rich inland waters the applicability of exclusively Phoslock(®) as FRP binder should be met critically. In addition, we observed a strong increase of filterable La in presence of humic substances reaching in a week more than 270 μg La l(-1) that would infer a violation of the Dutch La standard for surface water, which is 10.1 μg La l(-1). Hence, humic substances are an important factor that should be given attention when considering chemical FRP inactivation as they might play a substantial role in lowering the efficacy of metal-based FRP-sorbents, which makes measurements of humic substances (DOC) as well as controlled experiments vital.

  11. [Nitrate nitrogen leaching and residue of humic acid fertilizer in field soil].

    PubMed

    Liu, Fang-chun; Xing, Shang-jun; Duan, Chun-hua; Du, Zhen-yu; Ma, Hai-lin; Ma, Bing-yao

    2010-07-01

    To elucidate the potential influence of humic acidfertilizer on groundwater and soil quality in clay soil (CS) and sandy soil (SS), nitrate nitrogen leaching and residue of different fertilizers in field soil were studied using a self-made leaching field device. Nitrate nitrogen concentration in leaching water of fertilizer treatments was 28.1%-222.2% higher than that of non-nitrogen treatment in different times, but humic acid fertilizer could prevent nitrate nitrogen leaching both in CS and SS, especially in CS. Nitrate nitrogen concentration of leaching water in CS was 41.2%-59.1% less than that in SS and the inhibiting effect in CS was greater than that in SS. Nitrate nitrogen could be accumulated in soil profile by fertilizer application. The residue of nitrate nitrogen retained in 0-40 cm soil layer of humic acid fertilizer treatment was 59.8% and 54.4% respectively, higher than that of urea and compound fertilizer treatments. Nitrate nitrogen amount of humic acid, urea and compound fertilizer treatments in SS was significantly less than that in CS, being 81.7%, 81.1% and 47.6% respectively. Compared with the conventional fertilizer, humic acid fertilizer treatment improved the contents of organic matter, available nitrogen, phosphorus, and potassium of upper layer soil as well as cation exchange capacity. Besides, total amount of water-soluble salts in humic acid fertilizer treatment was decreased by 24.8% and 22.5% in comparison to urea and compound fertilizer treatments in CS, respectively. In summary, the application of humic acid fertilizer could improve physical and chemical properties of upper layer soil and reduce the risk of potential pollution to groundwater.

  12. The influence of humic acids derived from earthworm-processed organic wastes on plant growth.

    PubMed

    Atiyeh, R M; Lee, S; Edwards, C A; Arancon, N Q; Metzger, J D

    2002-08-01

    Some effects of humic acids, formed during the breakdown of organic wastes by earthworms (vermicomposting), on plant growth were evaluated. In the first experiment, humic acids were extracted from pig manure vermicompost using the classic alkali/acid fractionation procedure and mixed with a soilless container medium (Metro-Mix 360), to provide a range of 0, 50, 100, 150, 200, 250, 500, 1,000, 2,000, and 4,000 mg of humate per kg of dry weight of container medium, and tomato seedlings were grown in the mixtures. In the second experiment, humates extracted from pig manure and food wastes vermicomposts were mixed with vermiculite to provide a range of 0, 50, 125, 250, 500, 1,000, and 4,000 mg of humate per kg of dry weight of the container medium, and cucumber seedlings were grown in the mixtures. Both tomato and cucumber seedlings were watered daily with a solution containing all nutrients required to ensure that any differences in growth responses were not nutrient-mediated. The incorporation of both types of vermicompost-derived humic acids, into either type of soilless plant growth media, increased the growth of tomato and cucumber plants significantly, in terms of plant heights, leaf areas, shoot and root dry weights. Plant growth increased with increasing concentrations of humic acids incorporated into the medium up to a certain proportion, but this differed according to the plant species, the source of the vermicompost, and the nature of the container medium. Plant growth tended to be increased by treatments of the plants with 50-500 mg/kg humic acids, but often decreased significantly when the concentrations of humic acids derived in the container medium exceeded 500-1,000 mg/kg. These growth responses were most probably due to hormone-like activity of humic acids from the vermicomposts or could have been due to plant growth hormones adsorbed onto the humates.

  13. Phytoremediation of Cu and Zn by vetiver grass in mine soils amended with humic acids.

    PubMed

    Vargas, Carmen; Pérez-Esteban, Javier; Escolástico, Consuelo; Masaguer, Alberto; Moliner, Ana

    2016-07-01

    Phytoremediation of contaminated mine soils requires the use of fast-growing, deep-rooted, high-biomass, and metal-tolerant plants with the application of soil amendments that promote metal uptake by plants. A pot experiment was performed to evaluate the combined use of vetiver grass (Chrysopogon zizanioides) and humic acid for phytoremediation of Cu and Zn in mine soils. Vetiver plants were grown in soil samples collected from two mine sites of Spain mixed with a commercial humic acid derived from leonardite at doses of 0, 2, 10, and 20 g kg(-1). Plant metal concentrations and biomass were measured and metal bioavailability in soils was determined by a low molecular weight organic acid extraction. Results showed that humic acid addition decreased organic acid-extractable metals in soil. Although this extraction method is used to estimate bioavailability of metals, it was not a good estimator under these conditions due to competition with the strong chelators in the added humic acid. High doses of humic acid also promoted root growth and increased Cu concentrations in plants due to formation of soluble metal-organic complexes, which enhanced removal of this metal from soil and its accumulation in roots. Although humic acid was not able to improve Zn uptake, it managed to reduce translocation of Zn and Cu to aerial parts of plants. Vetiver resulted unsuitable for phytoextraction, but our study showed that the combined use of this species with humic acid at 10-20 g kg(-1) could be an effective strategy for phytostabilization of mine soils.

  14. Electrospray ionization mass spectrometry of terrestrial humic substances and their size fractions.

    PubMed

    Piccolo, A; Spiteller, M

    2003-11-01

    Electrospray ionization mass spectrometry (ESI-MS) was used to evaluate the average molecular mass of terrestrial humic substances, such as humic (HA) and fulvic (FA) acids from a soil, and humic acid from a lignite (NDL). Their ESI mass spectra, by direct infusion, gave average molecular masses comparable to those previously obtained for aquatic humic materials. The soil HA and FA were further separated in size-fractions by preparative high performance size exclusion chromatography (HPSEC) and analyzed with ESI-MS by both direct infusion and a further on-line analytical HPSEC. Unexpectedly, their average molecular mass was only slightly less than for the bulk sample and, despite different nominal molecular size, did not substantially vary among size-fractions. The values increased significantly (up to around 1200 Da) after on-line analytical HPSEC for the HA bulk sample, at both pH 8 and 4, and for the HA size-fractions when pH was reduced from 8 to 4. It was noticed that HA size-fractions at pH 8 were separated by on-line HPSEC in further peaks showing average masses which progressively increased with elution volume. Furthermore, when the HA and NDL bulk samples were sequentially ultracentrifuged at increasing rotational speed, their supernatants showed mass values which were larger than bulk samples and increased with rotational speed. These variations in mass values indicate that the electrospray ionization is dependent on the composition of the humic molecular mixtures and increases when their heterogeneity is progressively reduced. It is suggested that the dominance of hydrophobic compounds in humic supramolecular associations may inhibit the electrospray ionization of hydrophilic components. Our results show that ESI-MS is reasonably applicable to humic substances only after an extensive reduction of their chemical complexity.

  15. Quantitation of a minor enantiomer of phenanthrene tetraol in human urine: correlations with levels of overall phenanthrene tetraol, benzo[a]pyrene tetraol, and 1-hydroxypyrene.

    PubMed

    Hochalter, J Bradley; Zhong, Yan; Han, Shaomei; Carmella, Steven G; Hecht, Stephen S

    2011-02-18

    Polycyclic aromatic hydrocarbons (PAH) are well established carcinogens that are likely to play a role in causing some human cancers. One accepted pathway of PAH metabolic activation is the formation of bay region diol epoxides. Some individuals may be particularly susceptible to PAH carcinogenesis because they metabolically activate PAH more effectively than others. We have used the measurement of urinary phenanthrene tetraols (Phe-tetraols) as a biomarker of PAH exposure plus metabolic activation since bay region diol epoxides are hydrolyzed to tetraols. Because of stereoselectivity in Phe metabolism, Phe-(1R,2S,3R,4S)-tetraol (4) results mainly from the bay region diol epoxide pathway, and Phe-(1S,2R,3S,4R)-tetraol (7) is formed mainly from the reverse diol epoxide pathway, not generally associated with carcinogenicity. The latter pathway accounts for more than 95% of human urinary Phe-tetraol. In most previous studies, Phe-tetraol was quantified without enantiomeric resolution, using a relatively rapid and practical method, applicable to large studies. It was not clear, however, whether measurement of overall unresolved Phe-tetraol would accurately represent the bay region diol epoxide metabolic activation pathway. Therefore, in this study we specifically quantified Phe-(1R,2S,3R,4S)-tetraol (4) by supplementing our usual analysis with chiral HPLC separations and using [(13)C(6)]Phe-(1R,2S,3R,4S)-tetraol as internal standard. We then investigated the relationship of urinary levels of 4 to those of Phe-tetraols (4 + 7), quantified without enantiomeric resolution. We applied these methods to urine samples from cigarette smokers and highly PAH-exposed creosote workers. The results were also compared to levels of benzo[a]pyrene-7,8,9,10-tetraol and 1-hydroxypyrene in the same samples. Levels of 4 were highly correlated with those of 4 + 7 (r > 0.9, P < 0.0001) in both types of urine samples. Strong correlations of 4 and 4 + 7 with benzo[a]pyrene-7,8,9,10-tetraol

  16. Complete genome sequence of the phenanthrene-degrading soil bacterium Delftia acidovorans Cs1-4

    SciTech Connect

    Shetty, Ameesha R.; de Gannes, Vidya; Obi, Chioma C.; Lucas, Susan; Lapidus, Alla; Cheng, Jan-Fang; Goodwin, Lynne A.; Pitluck, Samuel; Peters, Linda; Mikhailova, Natalia; Teshima, Hazuki; Han, Cliff; Tapia, Roxanne; Land, Miriam; Hauser, Loren J.; Kyrpides, Nikos; Ivanova, Natalia; Pagani, Ioanna; Chain, Patrick S. G.; Denef, Vincent J.; Woyke, Tanya; Hickey, William J.

    2015-08-15

    Polycyclic aromatic hydrocarbons (PAH) are ubiquitous environmental pollutants and microbial biodegradation is an important means of remediation of PAH-contaminated soil. Delftia acidovorans Cs1-4 (formerly Delftia sp. Cs1-4) was isolated by using phenanthrene as the sole carbon source from PAH contaminated soil in Wisconsin. Its full genome sequence was determined to gain insights into a mechanisms underlying biodegradation of PAH. Three genomic libraries were constructed and sequenced: an Illumina GAii shotgun library (916,416,493 reads), a 454 Titanium standard library (770,171 reads) and one paired-end 454 library (average insert size of 8 kb, 508,092 reads). The initial assembly contained 40 contigs in two scaffolds. The 454 Titanium standard data and the 454 paired end data were assembled together and the consensus sequences were computationally shredded into 2 kb overlapping shreds. Illumina sequencing data was assembled, and the consensus sequence was computationally shredded into 1.5 kb overlapping shreds. Gaps between contigs were closed by editing in Consed, by PCR and by Bubble PCR primer walks. A total of 182 additional reactions were needed to close gaps and to raise the quality of the finished sequence. The final assembly is based on 253.3 Mb of 454 draft data (averaging 38.4 X coverage) and 590.2 Mb of Illumina draft data (averaging 89.4 X coverage). The genome of strain Cs1-4 consists of a single circular chromosome of 6,685,842 bp (66.7 %G+C) containing 6,028 predicted genes; 5,931 of these genes were protein-encoding and 4,425 gene products were assigned to a putative function. Genes encoding phenanthrene degradation were localized to a 232 kb genomic island (termed the phn island), which contained near its 3’ end a bacteriophage P4-like integrase, an enzyme often associated with chromosomal integration of mobile genetic elements. Other biodegradation pathways reconstructed from the genome sequence included: benzoate (by the acetyl-CoA pathway

  17. Complete genome sequence of the phenanthrene-degrading soil bacterium Delftia acidovorans Cs1-4

    DOE PAGES

    Shetty, Ameesha R.; de Gannes, Vidya; Obi, Chioma C.; ...

    2015-08-15

    Polycyclic aromatic hydrocarbons (PAH) are ubiquitous environmental pollutants and microbial biodegradation is an important means of remediation of PAH-contaminated soil. Delftia acidovorans Cs1-4 (formerly Delftia sp. Cs1-4) was isolated by using phenanthrene as the sole carbon source from PAH contaminated soil in Wisconsin. Its full genome sequence was determined to gain insights into a mechanisms underlying biodegradation of PAH. Three genomic libraries were constructed and sequenced: an Illumina GAii shotgun library (916,416,493 reads), a 454 Titanium standard library (770,171 reads) and one paired-end 454 library (average insert size of 8 kb, 508,092 reads). The initial assembly contained 40 contigs inmore » two scaffolds. The 454 Titanium standard data and the 454 paired end data were assembled together and the consensus sequences were computationally shredded into 2 kb overlapping shreds. Illumina sequencing data was assembled, and the consensus sequence was computationally shredded into 1.5 kb overlapping shreds. Gaps between contigs were closed by editing in Consed, by PCR and by Bubble PCR primer walks. A total of 182 additional reactions were needed to close gaps and to raise the quality of the finished sequence. The final assembly is based on 253.3 Mb of 454 draft data (averaging 38.4 X coverage) and 590.2 Mb of Illumina draft data (averaging 89.4 X coverage). The genome of strain Cs1-4 consists of a single circular chromosome of 6,685,842 bp (66.7 %G+C) containing 6,028 predicted genes; 5,931 of these genes were protein-encoding and 4,425 gene products were assigned to a putative function. Genes encoding phenanthrene degradation were localized to a 232 kb genomic island (termed the phn island), which contained near its 3’ end a bacteriophage P4-like integrase, an enzyme often associated with chromosomal integration of mobile genetic elements. Other biodegradation pathways reconstructed from the genome sequence included: benzoate (by the acetyl

  18. Magnetic adsorbents for the removal of Hg (II) and phenanthrene from aqueous solutions

    NASA Astrophysics Data System (ADS)

    Isari, Ekavi; Karapanagioti, Hrissi K.; Manariotis, Ioannis D.; Werner, David

    2015-04-01

    Activated carbon (AC) acts as a strong binding agent that lowers the pollutant concentration and, thus its toxicity. Another promising sorbent material in environmental applications is biochar (BC) which is obtained from the incomplete combustion of carbon-rich biomass under oxygen-limited conditions. Both of these materials could be used as soil or sediment amendments that would lower the toxicity in the aqueous phase. A draw back of this technique is that although the pollutant will remain non- bioavailable for many years being sorbed into these sorbents, it actually stays into the system. The objective of this study was (a) to synthesize a magnetic powdered activated carbon (AC/Fe) and magnetic powdered biochar (BC/Fe) produced from commercial AC1 and AC2 samples and biochar respectively and (b) to evaluate the potential use of AC/Fe and BIO/Fe to remove aqueous Hg (II) or phenanthrene while being magnetically recoverable. The BC was produced from olive pomace. The surface area, the pore volume, and the average pore size of each sorbent were determined using gas (N2) adsorption-desorption cycles and the Brunauer, Emmett, and Teller (BET) equation. Isotherms with 30 adsorption and 20 desorption points were conducted at liquid nitrogen temperature (77K). Open surface area and micropore volume were determined using t-plot method and Harkins & Jura equation. For both AC/Fe, surface area measurements resulted in 66% those of corresponding AC. For BC/Fe, the surface area was 82% that of BC. Batch experiments with all sorbent samples and mercury solutions were conducted at room temperature (25oC) and at pH 5 in order to compare the sorption properties of the materials. Similar tests were performed with phenanthrene solutions. Based on mercury isotherm data, AC/Fe and BC/Fe are effective sorbents but with lower sorption capacity compared to the initial materials (50-75% lower). All these properties point to promising materials that can effectively be used for in

  19. Bromoform formation in ozonated groundwater containing bromide and humic substances

    SciTech Connect

    Cooper, W.J.; Amy, G.L.; Moore, C.A.; Zika, R.G.

    1986-01-01

    The effect of bromide ion, organic carbon concentration (natural aquatic humic substances), pH, and solar irradiation on the formation of bromoform in ozonated groundwater has been studied. The studies were conducted on four unique samples of groundwater taken from different regions of the Biscayne Aquifer in southern Florida. All other conditions being equal, increases in bromide ion concentrations resulted in increases in CHBr/sub 3/ formation. In three of the four samples, CHBr/sub 3/ formation decreased as the pH level increased from 5 to 9. The fourth sample exhibited an opposite trend whereby the CHBr/sub 3/ concentration increased with increasing pH. Bromoform concentration increased with increased O/sub 3/ concentration over an ozone dosage range of 3.4 to 6.7 mg/L. Ozonated samples placed in sunlight immediately after ozone addition showed a decrease in the formation of CHBr/sub 3/ presumably due to the photodecomposition of HOBr/OBr.

  20. Supporting the process of removing humic substances on activated carbon.

    PubMed

    Olesiak, Paulina; Stępniak, Longina

    2014-01-01

    This study is focused on biosorption process used in water treatment. The process has a number of advantages and a lot of research has been done into its intensification by means of ultrasonic modification of solutions. The study carried out by the authors leads to the conclusion that sonication of organic solutions allows for extension of the time of operation of carbon beds. For the analysis of the results obtained during the sorption of humic substances (HS) from the solution dependencies UV/UV₀ or DOC/DOC₀ were used. In comparative studies the effectiveness of sorption and sonosorption (UV/UV₀) shows that the share of ultrasounds (US) is beneficial for extension of time deposit, both at a flow rate HS solution equal to 1 m/h and 5 m/h. Analysis of the US impact sorption on HS sorption in a biological fluidized bed, both prepared from biopreparat and the activated sludge confirms the higher efficiency compared to sonobiosorption than biosorption. These results confirm the degree of reduction UV₂₅₄/UV₀ and DOC/DOC₀ for the same processes. EMS index also confirms the improvement of HSbiodegradation by sludge microorganisms.

  1. Sorption of humic acids and alpha-endosulfan by clayminerals

    SciTech Connect

    Hengpraprom, S.; Lee, C.M.; Coates, R.T.

    2005-02-18

    Sorption of alpha-endosulfan by kaolinite andmontmorillonite alone and in the presence of sorbed and dissolved humicacid (HA) was investigated (pH 8 and 25oC). Three types of HA, Elliotsoil HA (EHA), Peat HA (PHA), and Summit Hill HA (SHHA), were used torepresent typical humic substances found in soils. For sorption of HA byeither mineral, Freundlich sorption coefficient (Kf) values appeared todecrease in the order of EHA>PHA>SHHA, which followedincreasing polarity (expressed as the O/C atomic ratio) and decreasingpercent-carbon content. For both clays, sorption of alpha-endosulfan bythe HA mineral complex was greater than for sorption by the clay alone.Sorption of alpha-endosulfan by the HA mineral complexes followed thesame order as the Kf of the HAs (EHA>PHA>SHHA). Based on theamount of HA adsorbed by each mineral, organic carbon partitioncoefficients (KOC) were determined for sorption of alpha-endosulfan bytwo of the HA mineral complexes. The value of KOC for alpha-endosulfansorption was greater for kaolinite EHA than kaolinite SHHA. However, theopposite trend was found with the montmorillonite HA complexes.Montmorillonite appeared to sorb alpha-endosulfan and/or HA with higheraffinity than kaolinite, which likely is due to its 2:1 layer structureand higher surface area. Sorption of endosulfan diol, a hydrolysisproduct, by the minerals was much less than the parentpesticide.

  2. Hygroscopic growth of atmospheric and model humic-like substances

    NASA Astrophysics Data System (ADS)

    Dinar, E.; Taraniuk, I.; Graber, E. R.; Anttila, T.; Mentel, T. F.; Rudich, Y.

    2007-03-01

    The hygroscopic growth (HG) of humic-like substances (HULIS) extracted from smoke and pollution aerosol particles and of Suwannee River fulvic acid (SRFA, bulk and fractions of different molecular weight) was measured by humidity tandem differential mobility analyzer (H-TDMA). By characterizing physical and chemical parameters such as molecular weight, elemental composition, and surface tension, we test the effect of these parameters on particle interactions with water vapor. For molecular weight-fractionated SRFA fractions, the growth factor at 90% relative humidity was generally inversely proportional to the molecular weight. HULIS extracts from ambient particles are more hygroscopic than all the SRFA fractions and exhibit different hygroscopic properties depending on their origin and residence time in the atmosphere. The results point out some dissimilarities between SRFA and aerosol-derived HULIS. The cloud condensation nuclei (CCN) behavior of the studied materials was predicted on the basis of hygroscopic growth using a recently introduced approach of Kreidenweis et al. (2005) and compared to CCN activity measurements on the same samples (Dinar et al., 2006). It is found that the computational approach (Kreidenweis et al., 2005) works reasonably well for SRF