Prétraitement de sédiments de dragage par une méthode électrocinétique

Nous avons évalué sous différentes conditions les performances de la déshydratation d'un sédiment causée sous l'effet combiné de la gravité et d'un champ électrique par rapport à celle obtenue sous l'effet gravitaire. Les résultats montrent que la déshydratation et la consolidation d'un matériau sont nettement accélérées sous l'effet d'un champ électrique, ainsi qu'un front basique qui s'installe dans l'échantillon, durant l'essai. Les effluents recueillis seront analysés afin d'évalué l'atténuation des contaminations

Influence of a mixture of metals on PAHs biodegradation processes in soils

In order to assess the effect of mixed pollutants, the influence of different concentration levels of a mixture of metals (Cr, Co, Pb, Mn, Ni, Cu, Zn) on the biodegradation of some PAHs (phenanthrene, fluoranthene, pyrene, benzo[b]fluoranthene and benzo[a]pyrene) in soil samples was evaluated. To do so, groups of microcosms of a natural soil fromthe region of Sabadell (Barcelona, Spain)were prepared as a reproduction of the native environment at laboratory scale, under controlled conditions. Mixtures of PAHs and metals were carefully selected, according to soil characterization and microbiological growth preliminary assays, and were added to microcosms. These microcosms were analyzed at various times, along two months, to obtain PAHs dissipation time-courses. A first-order kinetic modelling allowed obtaining different rate constants and DT50 values as a function of the metal levels introduced in microcosms. As a general observation, the higher the concentration of metals, the lower the biodegradation of PAHs of 3–4 rings (phenanthrene, fluoranthene and pyrene). On the other hand, no important effect on the biodegradation of higher molecular weight PAHs (benzo[b]fluoranthene and benzo[a]pyrene) was observed at the different concentration levels of metals testedPostprint (author's final draft

Novel Application of Cyclolipopeptide Amphisin: Feasibility Study as Additive to Remediate Polycyclic Aromatic Hydrocarbon (PAH) Contaminated Sediments

To decontaminate dredged harbor sediments by bioremediation or electromigration processes, adding biosurfactants could enhance the bioavailability or mobility of contaminants in an aqueous phase. Pure amphisin from Pseudomonas fluorescens DSS73 displays increased effectiveness in releasing polycyclic aromatic hydrocarbons (PAHs) strongly adsorbed to sediments when compared to a synthetic anionic surfactant. Amphisin production by the bacteria in the natural environment was also considered. DSS73’s growth is weakened by three model PAHs above saturation, but amphisin is still produced. Estuarine water feeding the dredged material disposal site of a Norman harbor (France) allows both P. fluorescens DSS73 growth and amphisin production

La Dépollution des sols et des sédiments par des procédés électrocinétiques

National audienc

Développement d'une nouvelle approche expérimentale pour évaluer la bio-accessibilité de contaminants organiques persistants dans des matrices sédimentaires

National audienc

Analytical investigation of the self desorption of the oligomers of mixtures of a polydisperse ethoxylated surfactant with SDS from a silica/water interface

International audienc

Analytical study of highly condensed non ionic surfactants. Separation on cation exchangers

International audienc

Analyse par spectrométrie de masse FAB de solutions diluées de tensioactifs polyoxyéthylénés. Application à l’étude de leur adsorption sur la silice en solution aqueuse.

International audienc

A new analytical methodology for a fast evaluation of semi-volatile polycyclic aromatic hydrocarbons in the vapor phase downstream of a diesel engine particulate filter.

International audienceA new sampling method was developed to collect vapor-phase polycyclic aromatic compounds (PAHs) downstream of a diesel engine equipped with a diesel particulate filter (DPF). This configuration allowed us to collect separately the particulate phase, which was trapped inside the DPF, and the vapor phase, which was sampled downstream of the DPF. PAHs, which were not predominantly absorbed into the poor organic fraction of the diesel soot, but were rather physically sorbed on high energetic adsorption sites, should be extracted using very drastic extraction conditions Microwave-assisted extraction using solvent mixtures composed of pyridine and diethylamine were used to desorb particulate PAHs, and the total PAH amounts corresponded to a very low value, i.e., 8 μg g⁻¹ or 0.24 μg km⁻¹, with a predominance of low weight PAHs. For collection of the vapor phase, gas bubbling in an aqueous medium was preferred to conventional methods, e.g., trapping on solid sorbents, for several reasons: aqueous trapping allowed us to use a solid phase enrichment process (SPE) that permitted PAH sampling at the sub-picogram levels. Consequently, low volume sampling was possible even if the sampling duration was very short (20 min). Additionally, the amount of time saved for the analysis was considerable when coupling SPE to the analytical system (liquid chromatography with fluorimetric detection). Solvent consumption for the overall sampling and analytical processes was also drastically reduced. Experiments on a diesel engine showed that vapor phase samples collected downstream of the DPF contained all of the 15 target priority PAHs, even the heaviest ones. The total vapor-phase PAH amount was 6.88 μg N m⁻³ or 10.02 μg km⁻¹, which showed that the gaseous fraction contains more PAHs than the particulate fraction. Partitioning coefficients (K(p)) were estimated showing the predominance in the vapor phase of all the PAHs. However, the DPF technology effects a considerable decrease in the total PAH emission when compared to non-equipped diesel vehicles

Analytical Tools for Multi-residue Analysis of some Oxygenated Metabolites of PAHs (Hydroxylated Quinones) in Sediments

International audienc