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Bacterial oxidation of arsenic in polluted soils: role of organic matters
2012
Lescure, Tiffanie | Joulian, Catherine | Bauda, Pascale | Hénault, Catherine | Battaglia-Brunet, Fabienne
Microbes play a major role on the behavior of metals and metalloids in soils. Arsenic speciation, in particular, is related to the activity of bacteria able to oxidize, reduce or methylate this element, and determines mobility, bioavailability and toxicity of As. Arsenate (AsV) is less toxic and less mobile than arsenite (AsIII). Bacterial As(III)-oxidation tends therefore to reduce the toxicity of arsenic in soils and its risk of transfer toward underlying aquifers. It is well known that organic matter influences abiotically the speciation of arsenic and thus its mobility in soils. Previous results suggest an effect of organic matter on the kinetics or efficiency of bacterial As(III)-oxidation in presence of oxygen, thus in conventional physico-chemical conditions of a surface soil. The objective of the present project is to quantify the influence of organic matters on the bacterial speciation of arsenic in polluted soils. Moreover, the biogeochemical consequences of this phenomenon on the mobility and ecotoxicity of this metalloid will be studied. The first task of this program is the systematic investigation of the influence of different types and concentrations of organic matters on the activity of As(III)-oxidizing pure strains. Influence of simple substrates (aspartate, succinate) and complex substrate (yeast extract) on As(III)-oxidation kinetics has been studied. For each experiment, the bacterial growth and the expression of genes involved in the speciation of arsenic, i.e. aio and ars genes, has been monitored. A direct perspective of this work will be to perform experiments with humic and fulvic acids (complex organic matter commonly found in soils), and with water-extracted organic matter from polluted soils. Then the As(III)-oxidation activity of bacterial communities extracted from contaminated soils will be followed. These assays should allow the screening of conditions which will be applied in subsequent experiments with several real contaminated soils, including a former mining site, impacted industrial sites, and a forest soil heavily contaminated after arsenical ammunitions storage. This work is co-funded by BRGM and ADEME (convention TEZ 11-16).
Show more [+] Less [-]Effectiveness Of Grass Filters In Reducing Phosphorus And Sediment Runoff
2012
Al-Wadaey, Ahmed | Wortmann, S. Charles | Franti, G. Thomas | Shapiro, A. Charles | Eisenhauer, E.Dean
Surface water contamination can often be reduced by passing runoff water through perennial grass filters. Research was conducted in 2006 to 2008 to evaluate the size of cool season grass filters consisting primarily of tall fescue (Festuca arundinacea Schreb) with some orchard grass (Dactylis glomerata L.) relative to drainage area size in reducing runoff sediment and phosphorus (P). The soil was Pohocco silt loam Typic Eutrochrepts with a median slope of 5.5 %. The grass filters occupying 1.1 and 4.3 % of the plot area were compared with no filter with four replications. The filters were planted in the V-shaped plot outlets which were 3.7x11.0 m in size. The filter effect on sediment and P concentration was determined from four natural runoff events when nearly all plots had runoff. Filter effect on runoff volume and contaminant load was determined using total runoff and composites of samples collected from 12 runoff events. Sediment concentration was reduced by 25 % with filters compared with no filter (from 1.10 to 1.47 gL(-1)), but P concentration was not affected. The 1.1 and 4.3 % filters, respectively, compared with having no grass filter, reduced: runoff volume by 54 and 79 %; sediment load by 67 and 84 % (357 to 58 kgha(-1)); total P load by 68 and 76 % (0.58 to 0.14 kgha(-1)); particulate P (PP) load by 66 and 82 % (0.39 to 0.07 kgha(-1)); and dissolved reactive P (DRP) load by 73 and 66 % (0.2 to 0.07 kgha(-1)), respectfully. A snowmelt runoff event had 56 % greater DRP concentration compared with rainfall-induced runoff events. Grass filters reduced sediment and P load largely by reducing runoff volume rather than reducing concentration. Well-designed and well-placed grass filters that occupy 1.0 to 1.5 % of the drainage area and intercept a uniform flow of runoff from a drainage area can reduce sediment and nutrient loss in runoff by greater than 50 %.
Show more [+] Less [-]Using a two site-reactive model for simulating one century changes of Zn and Pb concentration profiles in soils affected by metallurgical fallout
2012
Mallmann , Fábio Joel Kochem (Universidade Federal de Santa Maria, Santa Maria(Brésil). Departamento de Solos) | Rheinheimer , Danilo dos Santos (Universidade Federal de Santa Maria, Santa Maria(Brésil). Departamento de Solos) | Labanowski , Jérôme (Centre National de la Recherche Scientifique, Poitiers(France). UMR 6008, LCME, Université de Poitiers-ESIP) | Cambier , Philippe (INRA , Versailles (France). UR 0251 Physico-chimie et Ecotoxicologie des Sols d'agrosystèmes contaminés) | Lamy , Isabelle (INRA , Versailles (France). UR 0251 Physico-chimie et Ecotoxicologie des Sols d'agrosystèmes contaminés) | Santanna , Maria Alice (Universidade Federal de Santa Maria, Santa Maria(Brésil). Departamento de Física) | Tessier , Daniel (INRA , Versailles (France). UR 0251 Physico-chimie et Ecotoxicologie des Sols d'agrosystèmes contaminés) | Van Oort , Folkert (INRA , Versailles (France). UR 0251 Physico-chimie et Ecotoxicologie des Sols d'agrosystèmes contaminés)
Predicting the transfer of contaminants in soils is often hampered by lacking validation of mathematical models. Here, we applied Hydrus-2D software to three agricultural soils for simulating the 1900–2005 changes of zinc and lead concentration profiles derived from industrial atmospheric deposition, to validate the tested models with plausible assumptions on past metal inputs to reach the 2005 situation. The models were set with data from previous studies on the geochemical background, estimated temporal metal deposition, and the 2005 metal distributions. Different hypotheses of chemical reactions of metals with the soil solution were examined: 100% equilibrium or partial equilibrium, parameterized following kinetic chemical extractions. Finally, a two-site model with kinetic constant values adjusted at 1% of EDTA extraction parameters satisfactory predicted changes in metal concentration profiles for two arable soils. For a grassland soil however, this model showed limited applicability by ignoring the role of earthworm activity in metal incorporation.
Show more [+] Less [-]Functional traits of soil invertebrates as indicators for exposure to soil disturbance
2012
Hedde , Mickaël (INRA , Versailles (France). UR 0251 Physico-chimie et Ecotoxicologie des Sols d'agrosystèmes contaminés) | Van Oort , Folkert (INRA , Versailles (France). UR 0251 Physico-chimie et Ecotoxicologie des Sols d'agrosystèmes contaminés) | Lamy , Isabelle (INRA , Versailles (France). UR 0251 Physico-chimie et Ecotoxicologie des Sols d'agrosystèmes contaminés)
We tested a trait-based approach to link a soil disturbance to changes in invertebrate communities. Soils and macro-invertebrates were sampled in sandy soils contaminated by long-term wastewater irrigation, adding notably organic matter and trace metals (TM). We hypothesized that functional traits of invertebrates depict ways of exposure and that exposure routes relate to specific TM pools. Geophages and soft-body invertebrates were chosen to inform on exposure by ingestion or contact, respectively. Trait-based indices depicted more accurately effects of pollution than community density and diversity did. Exposure by ingestion had more deleterious effects than by contact. Both types of exposed invertebrates were influenced by TM, but geophages mainly responded to changes in soil organic matter contents. The trait-based approach requires to be applied in various conditions to uncorrelate specific TM impacts from those of other environmental factors.
Show more [+] Less [-]Spatial dynamics in biofilms architecture | Conférence invitée
2012
Deschamps, Julien | Briandet, Romain | MICrobiologie de l'ALImentation au Service de la Santé (MICALIS) ; Institut National de la Recherche Agronomique (INRA)-AgroParisTech | Université Paris Saclay (COmUE)
International audience
Show more [+] Less [-]Arsenic fractionation in mine spoils 10 years after aided phytostabilization
2012
Kumpiene, Jurate | Fitts, Jeffrey P. | Mench, Michel | Division of Waste Science and Technology ; Luleå University of Technology = Luleå Tekniska Universitet (LUT) | Environmental Sciences Department ; Brookhaven National Laboratory [Upton, NY] (BNL) ; UT-Battelle, LLC-Stony Brook University [SUNY] (SBU) ; State University of New York (SUNY)-State University of New York (SUNY)-U.S. Department of Energy [Washington] (DOE)-UT-Battelle, LLC-Stony Brook University [SUNY] (SBU) ; State University of New York (SUNY)-State University of New York (SUNY)-U.S. Department of Energy [Washington] (DOE) | Biodiversité, Gènes & Communautés (BioGeCo) ; Institut National de la Recherche Agronomique (INRA)-Université de Bordeaux (UB)
International audience | Aided phytostabilization using a combination of compost, zerovalent iron grit and coal fly ash (CZA) amendments and revegetation effectively promoted the biological recovery of mining spoils generated at a gold mine in Portugal. Selective dissolution of spoil samples in combination with solid phase characterization using microbeam X-ray absorption near edge structure (μXANES) spectroscopy and microbeam X-ray fluorescence (μXRF) mapping were used to assess As associations in spoils ten years after CZA treatment. The results show that As preferentially associates with poorly crystalline Fe-oxyhydroxides as opposed to crystalline Fe-(oxyhydr)oxide phases. The crystalline Fe(III)-phases dominated in the treated spoil and exceeded those of the untreated spoil three-fold, but only 2.6–6.8% of total As was associated with this fraction. Correlation maps of As:Fe reveal that As in the CZA-treated spoils is primarily contained in surface coatings as precipitates and sorbates. Arsenic binding with poorly crystalline Fe-oxyhydroxides did not inhibit As uptake by plants.
Show more [+] Less [-]How can magnetic resonance imaging (MRI) and particulate contrast agents with finely tuned interfacial properties help understanding particle transport in soil.
2012
Michel, E. | Faure, P. | Guillet, P. | Lafolie, Francois | Neveu, S. | Sammartino, Stéphane | Polidori, A.
From soil to edible plant parts: how to predict and limit contaminationof crops by inorganic trace elements?
2012
Nguyen, Christophe | Cornu, Jean-Yves | Denaix, Laurence | Laporte, Marie-Aline | Sappin-Didier, Valerie, | Schneider, Andre | Zarouali, Nadia
Modelling of cadmium uptake by plant roots in agricultural soil: construction and sensitivity analysis of the model
2012
Zhongbin, Lin | Nguyen, Christophe | Schneider, Andre
Modelling of cadmium uptake by plant roots in agricultural soils. Exploration by steady-state analytical solution of numeric simulation results
2012
Schneider, Andre | Zhongbin, Lin | Nguyen, Christophe