Уточнить поиск
Результаты 71-80 из 3,243
Development and applications of a DNA labeling method with magnetic nanoparticles to study the role of horizontal gene transfer events between bacteria in soil pollutant bioremediation processes
2015
Pivetal, Jérémy | Frénéa-Robin, Marie | Haddour, Naoufel | Vézy, C. | Zanini, L.-F. | Ciuta, Georgeta | Dempsey, Nora | Dumas-Bouchiat, Frédéric | Reyne, Gilbert | Bégin-Colin, S. | Felder-Flesh, D. | Ghobril, C. | Pourroy, G. | Simonet, Pascal | Ampère, Département Bioingénierie (BioIng) ; Ampère (AMPERE) ; École Centrale de Lyon (ECL) ; Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL) ; Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon) ; Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-École Centrale de Lyon (ECL) ; Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL) ; Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon) ; Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE) | Micro et NanoMagnétisme (NEEL - MNM) ; Institut Néel (NEEL) ; Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS) | Laboratoire de Génie Electrique de Grenoble (G2ELab) ; Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS) | Science des Procédés Céramiques et de Traitements de Surface (SPCTS) ; Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM) ; Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie - CNRS Chimie (INC-CNRS)-Centre National de la Recherche Scientifique (CNRS) | Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS) ; Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE) ; Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie - CNRS Chimie (INC-CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie - CNRS Chimie (INC-CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique ; Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS) | CNRS and Cemagref interdisciplinary Ecological engineering program 2009 (“Nanogénomique” project) | ANR-09-CESA-0013,EMERGENT,Développement et application d'une méthode de marquage de l'ADN par des nanoparticules magnétiques pour définir le rôle des transferts horizontaux de gènes entre bactéries dans les processus de bio-atténuation des polluants du sol,(2009)
International audience | Horizontal gene transfers are critical mechanisms of bacterial evolution and adaptation that are involved to a significant level in the degradation of toxic molecules such as xenobiotic pesticides. However, understanding how these mechanisms are regulated in situ and how they could be used by man to increase the degradation potential of soil microbes is compromised by conceptual and technical limitations. This includes the physical and chemical complexity and heterogeneity in such environments leading to an extreme bacterial taxonomical diversity and a strong redundancy of genes and functions. In addition, more than 99 % of soil bacteria fail to develop colonies in vitro, and even new DNA-based investigation methods (metagenomics) are not specific and sensitive enough to consider lysis recalcitrant bacteria and those belonging to the rare biosphere. The objective of the ANR funded project “Emergent” was to develop a new culture independent approach to monitor gene transfer among soil bacteria by labeling plasmid DNA with magnetic nanoparticles in order to specifically capture and isolate recombinant cells using magnetic microfluidic devices. We showed the feasibility of the approach by using electrotransformation to transform a suspension of Escherichia coli cells with biotin-functionalized plasmid DNA molecules linked to streptavidin-coated superparamagnetic nanoparticles. Our results have demonstrated that magnetically labeled cells could be specifically retained on micromagnets integrated in a microfluidic channel and that an efficient selective separation can be achieved with the microfluidic device. Altogether, the project offers a promising alternative to traditional culture-based approaches for deciphering the extent of horizontal gene transfer events mediated by electro or natural genetic transformation mechanisms in complex environments such as soil.
Показать больше [+] Меньше [-]Isolation and characterization of Bradyrhizobium sp. SR1 degrading two β-triketone herbicides
2015
Romdhane, Sana | Devers-Lamrani, Marion | Martin-Laurent, Fabrice | Calvayrac, Christophe | Rocaboy-Faquet, Emilie | Riboul, David | Cooper, Jean-François | Barthelmebs, Lise | Laboratoire de Chimie des Biomolécules et de l'Environnement (LCBE) ; Université Montpellier 1 (UM1)-Université de Perpignan Via Domitia (UPVD) | Agroécologie [Dijon] ; Institut National de la Recherche Agronomique (INRA)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement | Laboratoire de Biodiversité et Biotechnologies Microbiennes (LBBM) ; Observatoire océanologique de Banyuls (OOB) ; Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-PIERRE FABRE-EDF (EDF)-Centre National de la Recherche Scientifique (CNRS) | Laboratoire de Génie Chimique (LGC) ; Université Toulouse III - Paul Sabatier (UT3) ; Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP) ; Université de Toulouse (UT)
International audience | In this study, a bacterial strain able to use sulcotrione,a β-triketone herbicide, as sole source of carbon and energy was isolated from soil samples previously treated with this herbicide. Phylogenetic study based on16S rRNA gene sequence showed that the isolate has 100 % of similarity with several Bradyrhizobium and was accordingly designated as Bradyrhizobium sp. SR1. Plasmid profiling revealed the presence of a large plasmid (>50 kb) in SR1 not cured under nonselective conditions. Its transfer to Escherichia coli by electroporation failed to induce β-triketone degrading capacity,suggesting that degrading genes possibly located on this plasmid cannot be expressed in E. coli or that they are not plasmid borne. The evaluation of the SR1 ability to degrade various synthetic (mesotrione and tembotrione) and natural (leptospermone) triketones showed that this strain was also able to degrademesotrione. Although SR1 was able to entirely dissipate both herbicides, degradation rate of sulcotrione was ten times higher than that of mesotrione, showing a greater affinity of degrading-enzyme system to sulcotrione. Degradation pathway of sulcotrione involved the formation of 2-chloro-4-mesylbenzoic acid (CMBA), previously identified in sulcotrione degradation, and of a new metabolite identified as hydroxy-sulcotrione.Mesotrione degradation pathway leads to the accumulation of-methylsulfonyl-2-nitrobenzoic acid(MNBA) and 2-amino-4 methylsulfonylbenzoic acid(AMBA), two well-known metabolites of this herbicide. Along with the dissipation of β-triketones, one could observe the decrease in 4-hydroxyphenylpyruvate dioxygenase(HPPD) inhibition, indicating that toxicity was due to parent molecules, and not to the formed metabolites. This is the first report of the isolation of bacterial strain able to transform two β-triketones.
Показать больше [+] Меньше [-]Impact of insecticide exposure on the predation activity of the European earwig Forficula auricularia
2015
Malagnoux, Laure | Capowiez, Yvan | Rault, Magali | Institut méditerranéen de biodiversité et d'écologie marine et continentale (IMBE) ; Avignon Université (AU)-Aix Marseille Université (AMU)-Institut de recherche pour le développement [IRD] : UMR237-Centre National de la Recherche Scientifique (CNRS) | Abeilles et environnement (AE) ; Institut National de la Recherche Agronomique (INRA) | Unité de recherche Plantes et Systèmes de Culture Horticoles (PSH) ; Institut National de la Recherche Agronomique (INRA) | Avignon Université (AU) | Provence-Alpes-Cote d'Azur Region (France)
International audience | The European earwig Forficula auricularia is an effective predator in apple orchards. It is therefore crucial to study whether insecticides affect this natural pest control agent. Predation activity, i.e., the number of aphids eaten in 24 h, was determined under laboratory conditions after exposure of fourth-instar nymphs and adult earwigs to widely used insecticides (acetamiprid, chlorpyrifos-ethyl, deltamethrin, and spinosad), which were applied at the normal application rates. Inhibition of acetylcholinesterase and carboxylesterase activities were also measured as indicators of pesticide exposure. Predation activity decreased significantly in nymphs exposed to spinosad (62 %) and chlorpyrifos-ethyl (98 %) compared with controls. A similar response was found for both esterase activities. Spinosad had a stronger effect on AChE (-33 %) whereas chlorpyrifos-ethyl affected CbE activity preferentially (-59 %). Spinosad (20 % of controls), acetamiprid (28 %), and chlorpyrifos-ethyl (66 %) also significantly decreased the predation behavior of adult male but not female (5 to 40 %) earwigs. Adult AChE and CbE activities were also significantly reduced (28 to 67 % of controls) in pesticide-exposed earwigs. Our results suggest that earwigs should be included in the environmental risk assessment framework for authorization of newly marketed plant protection products. Their predation behavior appears to be a sensitive and complementary biomarker.
Показать больше [+] Меньше [-]Systemic insecticides (neonicotinoids and fipronil): trends, uses, mode of action and metabolites
2015
Simon-Delso, N | Amaral-Rogers, V. | Belzunces, Luc | Bonmatin, J-M. | Chagnon, M. | Downs, C. | Furlan, L. | Gibbons, D.W. | Giorio, C. | Girolami, V. | Goulson, D. | Kreutzweiser, D.P. | Krupke, C. | Liess, M. | Long, E. | Mcfield, M. | Mineau, P. | Mitchell, E.A.D. | Morrissey, C.A. | Noome, D.A. | Pisa, L | Settele, J. | Stark, J. D. | Tapparo, A. | van Dyck, H. | van Praagh, J.P. | van Der Sluijs, J. P. | Whitehorn, P.R. | Wiemers, M. | Universiteit Utrecht / Utrecht University [Utrecht] | Centre Apicole de Recherche et Information ; Partenaires INRAE | Buglife | Abeilles et environnement (AE) ; Institut National de la Recherche Agronomique (INRA) | Centre de biophysique moléculaire (CBM) ; Université d'Orléans (UO)-Université de Tours (UT)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie - CNRS Chimie (INC-CNRS)-Centre National de la Recherche Scientifique (CNRS) | Département des Sciences Biologiques ; Université du Québec à Montréal = University of Québec in Montréal (UQAM) | Haereticus Environmental Laboratory ; Partenaires INRAE | Veneto Agricoltura | Centre for Conservation Science | Department of Chemistry ; University of Cambridge [UK] (CAM) | Università degli Studi di Padova = University of Padua (Unipd) | School of Life Sciences ; University of Sussex | Canadian Forest Service ; Natural Resources Canada (NRCan) | Department of Entomology ; Michigan State University [East Lansing] ; Michigan State University System-Michigan State University System | Helmholtz Zentrum für Umweltforschung = Helmholtz Centre for Environmental Research (UFZ) | Smithsonian Institution | Pierre Mineau Consulting ; Partenaires INRAE | Laboratory of Soil Biology ; Université de Neuchâtel = University of Neuchatel (UNINE) | Jardin Botanique de Neuchâtel | University of Saskatchewan [Saskatoon, Canada] (U of S) | Kijani ; Partenaires INRAE | Department of Community Ecology ; Helmholtz Zentrum für Umweltforschung = Helmholtz Centre for Environmental Research (UFZ) | German Centre for Integrative Biodiversity Research (iDiv) | Washington State University (WSU) | Université Catholique de Louvain = Catholic University of Louvain (UCL) | Scientific Advisor ; Partenaires INRAE | University of Bergen (UiB) | School of Natural Sciences ; University of Stirling
International audience | Since their discovery in the late 1980s, neonicotinoid pesticides have become the most widely used class of insecticides worldwide, with large-scale applications ranging from plant protection (crops, vegetables, fruits), veterinary products, and biocides to invertebrate pest control in fish farming. In this review, we address the phenyl-pyrazole fipronil together with neonicotinoids because of similarities in their toxicity, physicochemical profiles, and presence in the environment. Neonicotinoids and fipronil currently account for approximately one third of the world insecticide market; the annual world production of the archetype neonicotinoid, imidacloprid, was estimated to be ca. 20,000 tonnes active substance in 2010. There were several reasons for the initial success of neonicotinoids and fipronil: (1) there was no known pesticide resistance in target pests, mainly because of their recent development, (2) their physicochemical properties included many advantages over previous generations of insecticides (i.e., organophosphates, carbamates, pyrethroids, etc.), and (3) they shared an assumed reduced operator and consumer risk. Due to their systemic nature, they are taken up by the roots or leaves and translocated to all parts of the plant, which, in turn, makes them effectively toxic to herbivorous insects. The toxicity persists for a variable period of time—depending on the plant, its growth stage, and the amount of pesticide applied. Awide variety of applications are available, including the most common prophylactic non-Good Agricultural Practices (GAP) application by seed coating. As a result of their extensive use and physicochemical properties, these substances can be found in all environmental compartments including soil, water, and air. Neonicotinoids and fipronil operate by disrupting neural transmission in the central nervous system of invertebrates. Neonicotinoids mimic the action of neurotransmitters, while fipronil inhibits neuronal receptors. In doing so, they continuously stimulate neurons leading ultimately to death of target invertebrates. Like virtually all insecticides, they can also have lethal and sublethal impacts on non-target organisms, including insect predators and vertebrates. Furthermore, a range of synergistic effects with other stressors have been documented. Here, we review extensively their metabolic pathways, showing how they form both compound-specific and common metabolites which can themselves be toxic. These may result in prolonged toxicity. Considering their wide commercial expansion, mode of action, the systemic properties in plants, persistence and environmental fate, coupled with limited information about the toxicity profiles of these compounds and their metabolites, neonicotinoids and fipronil may entail significant risks to the environment. A global evaluation of the potential collateral effects of their use is therefore timely. The present paper and subsequent chapters in this review of the global literature explore these risks and show a growing body of evidence that persistent, low concentrations of these insecticides pose serious risks of undesirable environmental impacts.
Показать больше [+] Меньше [-]Effects of neonicotinoids and fipronil on non-target invertebrates
2015
Pisa, L.W. | Amaral-Rogers, V. | Belzunces, Luc | Bonmatin, J-M. | Downs, C.A. | Goulson, D. | Kreutzweiser, D.P. | Krupke, C. | Liess, M. | Mcfield, M. | Morrissey, C.A. | Noome, D.A. | Settele, J. | Simon-Delso, N. | Stark, J. D. | van Der Sluijs, Jeroen P. | van Dyck, H. | Wiemers, M. | Universiteit Utrecht / Utrecht University [Utrecht] | Buglife | Abeilles et environnement (AE) ; Institut National de la Recherche Agronomique (INRA) | Centre de biophysique moléculaire (CBM) ; Université d'Orléans (UO)-Université de Tours (UT)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie - CNRS Chimie (INC-CNRS)-Centre National de la Recherche Scientifique (CNRS) | Haereticus Environmental Laboratory ; Partenaires INRAE | School of Life Sciences ; University of Sussex | Canadian Forest Service ; Natural Resources Canada (NRCan) | Department of Entomology ; Michigan State University [East Lansing] ; Michigan State University System-Michigan State University System | Helmholtz Zentrum für Umweltforschung = Helmholtz Centre for Environmental Research (UFZ) | Smithsonian Institution | University of Saskatchewan [Saskatoon, Canada] (U of S) | Kijani, Kasungu national park ; Partenaires INRAE | Department of Community Ecology ; Helmholtz Zentrum für Umweltforschung = Helmholtz Centre for Environmental Research (UFZ) | German Centre for Integrative Biodiversity Research (iDiv) | Centre Apicole de Recherche et Information ; Partenaires INRAE | Washington State University (WSU) | Centre for the Study of the Sciences and the Humanities (SVT) ; University of Bergen (UiB) | Université Catholique de Louvain = Catholic University of Louvain (UCL)
International audience | We assessed the state of knowledge regarding the effects of large-scale pollution with neonicotinoid insecticides and fipronil on non-target invertebrate species of terrestrial, freshwater and marine environments. A large section of the assessment is dedicated to the state of knowledge on sublethal effects on honeybees (<em>Apis mellifera</em>) because this important pollinator is the most studied non-target invertebrate species. Lepidoptera (butterflies and moths), Lumbricidae (earthworms), Apoidae sensu lato (bumblebees, solitary bees) and the section “other invertebrates” review available studies on the other terrestrial species. The sections on freshwater and marine species are rather short as little is known so far about the impact of neonicotinoid insecticides and fipronil on the diverse invertebrate fauna of these widely exposed habitats. For terrestrial and aquatic invertebrate species, the known effects of neonicotinoid pesticides and fipronil are described ranging from organismal toxicology and behavioural effects to population-level effects. For earthworms, freshwater and marine species, the relation of findings to regulatory risk assessment is described. Neonicotinoid insecticides exhibit very high toxicity to a wide range of invertebrates, particularly insects, and field-realistic exposure is likely to result in both lethal and a broad range of important sublethal impacts. There is a major knowledge gap regarding impacts on the grand majority of invertebrates, many of which perform essential roles enabling healthy ecosystem functioning. The data on the few non-target species on which field tests have been performed are limited by major flaws in the outdated test protocols. Despite large knowledge gaps and uncertainties, enough knowledge exists to conclude that existing levels of pollution with neonicotinoids and fipronil resulting from presently authorized uses frequently exceed the lowest observed adverse effect concentrations and are thus likely to have large-scale and wide ranging negative biological and ecological impacts on a wide range of non-target invertebrates in terrestrial, aquatic, marine and benthic habitats.
Показать больше [+] Меньше [-]PAH occurrence in chalk river systems from the Jura region (France). Pertinence of suspended particulate matter and sediment as matrices for river quality monitoring
2015
Chiffre, Axelle | Degiorgi, François | Morin-Crini, Nadia | Bolard, Audrey | Chanez, Etienne | Badot, Pierre-Marie | Laboratoire Chrono-environnement (UMR 6249) (LCE) ; Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC) ; Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC) | Centre National de la Recherche Scientifique (CNRS) | Institut National de la Recherche Agronomique (INRA)
International audience
Показать больше [+] Меньше [-]Isolation and characterization of Bradyrhizobium sp. SR1 degrading two β-triketone herbicides
2015
Romdhane, Sana | Devers-Lamrani, Marion | Martin-Laurent, Fabrice | Calvayrac, Christophe | Rocaboy-Faquet, Emilie | Riboul, David | Cooper, Jean-François | Barthelmebs, Lise | Laboratoire de Chimie des Biomolécules et de l'Environnement (LCBE) ; Université Montpellier 1 (UM1)-Université de Perpignan Via Domitia (UPVD) | Agroécologie [Dijon] ; Institut National de la Recherche Agronomique (INRA)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement | Laboratoire de Biodiversité et Biotechnologies Microbiennes (LBBM) ; Observatoire océanologique de Banyuls (OOB) ; Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-PIERRE FABRE-EDF (EDF)-Centre National de la Recherche Scientifique (CNRS) | Laboratoire de Génie Chimique (LGC) ; Université Toulouse III - Paul Sabatier (UT3) ; Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP) ; Université de Toulouse (UT)
International audience | In this study, a bacterial strain able to use sulcotrione,a β-triketone herbicide, as sole source of carbon and energy was isolated from soil samples previously treated with this herbicide. Phylogenetic study based on16S rRNA gene sequence showed that the isolate has 100 % of similarity with several Bradyrhizobium and was accordingly designated as Bradyrhizobium sp. SR1. Plasmid profiling revealed the presence of a large plasmid (>50 kb) in SR1 not cured under nonselective conditions. Its transfer to Escherichia coli by electroporation failed to induce β-triketone degrading capacity,suggesting that degrading genes possibly located on this plasmid cannot be expressed in E. coli or that they are not plasmid borne. The evaluation of the SR1 ability to degrade various synthetic (mesotrione and tembotrione) and natural (leptospermone) triketones showed that this strain was also able to degrademesotrione. Although SR1 was able to entirely dissipate both herbicides, degradation rate of sulcotrione was ten times higher than that of mesotrione, showing a greater affinity of degrading-enzyme system to sulcotrione. Degradation pathway of sulcotrione involved the formation of 2-chloro-4-mesylbenzoic acid (CMBA), previously identified in sulcotrione degradation, and of a new metabolite identified as hydroxy-sulcotrione.Mesotrione degradation pathway leads to the accumulation of-methylsulfonyl-2-nitrobenzoic acid(MNBA) and 2-amino-4 methylsulfonylbenzoic acid(AMBA), two well-known metabolites of this herbicide. Along with the dissipation of β-triketones, one could observe the decrease in 4-hydroxyphenylpyruvate dioxygenase(HPPD) inhibition, indicating that toxicity was due to parent molecules, and not to the formed metabolites. This is the first report of the isolation of bacterial strain able to transform two β-triketones.
Показать больше [+] Меньше [-]Transfer of metal(loid)s in a small vineyard catchment: contribution of dissolved and particulate fractions in river for contrasted hydrological conditions | Transfert des métaux/métalloides dans un petit bassin versant viticole : contribution des fractions dissoutes et particulaires dans la rivière dans des conditions hydrologiques contrastées
2015
Rabiet, Marie-Josèphe | Coquery, Marina | Carluer, Nadia | Gahou, J. | Gouy, Véronique | Milieux aquatiques, écologie et pollutions (UR MALY) ; Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)
[Departement_IRSTEA]Eaux [TR1_IRSTEA]ARCEAU [TR2_IRSTEA]BELCA | International audience | The use of inorganic pesticides in viticulture leads to the accumulation of metal(loid)s in soils which can be transferred to the hydro-systems (groundwater and surface water) via several processes. This study reports on the occurrence and behavior of metal(loid)s (Li, Al, Cr, Ni, Cu, Zn, As, Sr, and Ba), with a particular focus on Cu, Zn, and As, in a small stream draining a vineyard catchment. Base flow and flood events were monitored in order to assess the spatiotemporal variability of metal(loid) concentrations and to evaluate the contribution of the particulate fraction to the transfer of metal(loid)s according to the hydrological conditions. Results show that very different patterns of metal(loid)s were observed in the Morcille River according to the hydrological conditions. In base flow conditions, Cu and As were mainly transported in dissolved phase, which contributed to more than 70 and 80 %, respectively, of the total load during this period. On the contrary, during base flow, Zn was mainly transported as associated to particles (90 %). During the two storm events monitored, the particulate fraction was dominant, as its represented around 74–80 %, 97 %, and 50–70 % of the total Cu, Zn, and As load in the river, respectively. Thus,despite a weaker affinity for particles during floods (decrease of particulate content during floods), metal(loid)s were mainly brought as particles, given that high amounts of suspended particulate matter (up to 2031 mg/L) were mobilized. Finally, comprehensive fluxes estimations confirmed that floods were responsible for more than 90 % of the total Cu, Zn and 75 % for As load transiting in the Morcille River in August within a very short period of time (less than 17 %).
Показать больше [+] Меньше [-]Effects of cyanobacterial extracellular polymeric substances on the stability of ZnO nanoparticles in eutrophic shallow lakes
2015
Xu, Huacheng | Jiang, Helong
Extracellular polymeric substances (EPS) from bloom-forming cyanobacteria exist ubiquitously in eutrophic waters, while their effects on the aggregation/stabilization of nanoparticles remain unknown. In this study, the stability of ZnO nanoparticles (ZNPs) upon adsorption of cyanobacterial EPS was investigated by using two dimensional ATR-FTIR correlation spectroscopy, XPS and DLVO theory. Results showed that the adsorption process followed the Langmuir isotherm and pseudo-second-order kinetics both for the total organic contents as well as the individual parallel factor-derived components. The physicochemical and spectroscopic techniques revealed the mechanism of both electrostatic attraction and surface complexation in EPS adsorption. Further analysis showed increased absorbance and turbidity of ZNPs solutions with EPS addition, demonstrating the enhanced colloidal stability. The DLVO theory explained that the increased energy barriers and values of second energy maximum were responsible for the stability enhancement. This study facilitates a deeper insight into the environmental behavior of nanoparticles in eutrophic algae-rich waters.
Показать больше [+] Меньше [-]Surface–rain interactions: Differences in copper runoff for copper sheet of different inclination, orientation, and atmospheric exposure conditions
2015
Hedberg, Yolanda S. | Goidanich, Sara | Herting, Gunilla | Odnevall Wallinder, Inger
Predictions of the diffuse dispersion of metals from outdoor constructions such as roofs and facades are necessary for environmental risk assessment and management. An existing predictive model has been compared with measured data of copper runoff from copper sheets exposed at four different inclinations facing four orientations at two different urban sites (Stockholm, Sweden, and Milan, Italy) during a 4-year period. Its applicability has also been investigated for copper sheet exposed at two marine sites (Cadiz, Spain, for 5 years, and Brest, France, for 9 years). Generally the model can be used for all given conditions. However, vertical surfaces should be considered as surfaces inclined 60–80° due to wind-driven effects. The most important parameters that influence copper runoff, and not already included in the model, are the wind and rain characteristics that influence the actual rainfall volume impinging the surface of interest.
Показать больше [+] Меньше [-]