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Deschatre M.,Mexel Industries SAS | Deschatre M.,French Research Institute for Exploitation of the Sea | Ghillebaert F.,EcoTox | Guezennec J.,AiMB Advices in Marine Biotechnology | Colin C.S.,French Research Institute for Exploitation of the Sea
Applied Biochemistry and Biotechnology

Metal remediation was studied by the sorption of analytical grade copper Cu(II) and silver Ag(I) by four exopolysaccharides (EPS) produced by marine bacteria. Colorimetric analysis showed that these EPS were composed of neutral sugars, uronic acids (>20 %), acetate, and sulfate (29 %). Metal sorption experiments were conducted in batch process. Results showed that the maximum sorption capacities calculated according to Langmuir model were 400 mg g -1 EPS (6.29 mmol g-1) and 333 mg g-1 EPS (3.09 mmol g-1) for Cu(II) and Ag(I), respectively. Optimum pH values of Ag(I) sorption were determined as 5.7. Experiment results also demonstrated the influence of initial silver concentration and EPS concentrations. Microanalyzing coupled with scanning electron microscopy demonstrated the presence of metal and morphological changes of the EPS by the sorption of metallic cations. The Fourier transform infrared spectroscopy analysis indicated possible functional groups (e.g.; carboxyl, hydroxyl, and sulfate) of EPS involved in the metal sorption processes. These results showed that EPS from marine bacteria are very promising for copper and silver remediation. Further development in dynamic and continuous process at the industrial scale will be established next. © 2013 Springer Science+Business Media New York. Source

Deschatre M.,Mexel Industries SAS | Deschatre M.,CNRS Lab for Microbiology of Extreme Environments | Lescop B.,CNRS Brittany Magnetism Laboratory | Colin C.S.,CNRS Lab for Microbiology of Extreme Environments | And 3 more authors.
Journal of Environmental Chemical Engineering

Biosorption of silver ions by several exopolysaccharides (EPS) differing from each other in their chemical composition and functional groups was investigated. EPS were characterized before and after Ag(I) biosorption by comprehensively using X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, transmission electron microscopy (TEM). The role of the different functional groups in the biosorption process was observed. In particular, sulfate groups were seen playing a major role. XPS and FTIR methods showed that the composition of lowest efficient EPS changed after Ag(I) biosorption with a relative increase of the carboxylate ions content. This change was accompanied by the formation of mainly silver oxide nanoparticles. As the consequence, the reducing character of the EPS is expected to influence the silver sorption capability of the EPS. © 2014 Elsevier Ltd. All rights reserved. Source

Bouchoud L.,University of Geneva | Fonzo-Christe C.,University of Geneva | Klingmuller M.,EcoTox | Bonnabry P.,University of Geneva
Journal of Parenteral and Enteral Nutrition

Background and Aim: Hospitalized patients requiring parenteral nutrition (PN) often need to receive intravenous (IV) medications as well. Y-site administration is occasionally necessary, but physicochemical incompatibilities can occur between the medications and PN. The aim of the present study was to assess the physical compatibility between 25 frequently coadministered IV medications and a commercially available ready-to-use total PN. Methods: PN (NuTRIflex Lipid Special; B. Braun Medical AG, Sempach, Switzerland) and medications were mixed in 1:1 (v/v) proportions, and the stability was assessed at the time of mixing and after 1 and 4 hours. The stability of lipid emulsion was observed by microscopic investigation, visual inspection, dynamic laser light scattering, and laser light obscuration. The binary admixtures of PN (without lipid emulsion) and medications were used to detect discoloration, visibly detectable precipitates, and subvisual particles. Results: Two of 25 medications were incompatible with the lipid emulsion (serum albumin 20% and tropisetron), 2 showed signs of degradation (discoloration) over time (esomeprazole and pantoprazole), and 1 precipitated at high concentrations (5-fluorouracil). The other 20 medications were considered compatible when administered by Y-site. Conclusion: The present study validated the compatibility of 1 commercially available PN and 20 medications. These results offer new solutions to support the implementation of complex therapeutic schemes in practice, when coadministration via Y-site cannot be avoided. © 2012 American Society for Parenteral and Enteral Nutrition. Source

Brix K.V.,EcoTox | Brix K.V.,University of Miami | DeForest D.K.,Windward | Adams W.J.,Rio Tinto Alcan
Science of the Total Environment

Laboratory studies have traditionally indicated that aquatic insects are relatively insensitive to metals while field studies have suggested them to be among the most sensitive aquatic invertebrate taxa. We reviewed and synthesized available studies in the literature to critically assess why this discrepancy exists. Despite the intense effort to study the effects of metals on aquatic biota over the past several decades, we found studies specific to insects to still be relatively limited. In general, the discrepancy between laboratory and field studies continues with few efforts having been made to elucidate the ecological and physiological mechanisms that underlie the relative sensitivity (or insensitivity) of aquatic insects to metals. However, given the limited data available, it appears that aquatic insects are indeed relatively insensitive to acute metal exposures. In contrast, we suggest that some aquatic insect taxa may be quite sensitive to chronic metal exposure and in some cases may not be protected by existing water quality criteria for metals. The discrepancy between laboratory and field studies with respect to chronic sensitivity appears to largely be driven by the relatively short exposure periods in laboratory studies as compared to field studies. It also appears that, in some cases, the sensitivity of aquatic insects in field studies may be the result of direct effects on primary producers, which lead to indirect effects via the food chain on aquatic insects. Finally, available evidence suggests that diet is an important source of metal accumulation in insects, but to date there have been no conclusive studies evaluating whether dietary metal accumulation causes toxicity. There is a clear need for developing a more mechanistic understanding of aquatic insect sensitivity to metals in long-term laboratory and field studies. © 2011 Elsevier B.V. Source

Brix K.V.,EcoTox | Brix K.V.,University of Miami | Keithly J.,Parametrix Inc. | Santore R.C.,HydroQual | And 2 more authors.
Science of the Total Environment

Zinc (Zn) risks from stormwater runoff to an aquatic ecosystem were studied. Monitoring data on waterborne, porewater, and sediment Zn concentrations collected at 20 stations throughout a stormwater collection/detention facility consisting of forested wetlands, a retention pond and first order stream were used to conduct the assessment. Bioavailability in the water column was estimated using biotic ligand models for invertebrates and fish while bioavailability in the sediment was assessed using acid volatile sulfide-simultaneously extracted metal (AVS-SEM). The screening level assessment indicated no significant risks were posed to benthic organisms from Zn concentrations in sediments and pore water. As would be expected for stormwater, Zn concentrations were temporally quite variable within a storm event, varying by factors of 2 to 4. Overall, probabilistic assessment indicated low (5-10% of species affected) to negligible risks in the system, especially at the discharge to the first order stream. Moderate to high risks (10-50% of species affected) were identified at sampling locations most upgradient in the collection system. The largest uncertainty with the assessment is associated with how best to estimate chronic exposure/risks from time-varying exposure concentrations. Further research on pulse exposure metal toxicity is clearly needed to assess stormwater impacts on the environment. © 2009 Elsevier B.V. All rights reserved. Source

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