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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 | Year: 2013

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.


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 | Year: 2011

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.


Brix K.V.,EcoTox | Brix K.V.,University of Miami | Tellis M.S.,McMaster University | Cremazy A.,University of British Columbia | And 3 more authors.
Aquatic Toxicology | Year: 2016

Single metal Biotic Ligand Models (BLMs) have been developed for a number of metals and model organisms. While these BLMs improve our ability to regulate metals in the aquatic environment, in reality, organisms are often simultaneously exposed to metal mixtures. Recently, several attempts have been made to develop mixture BLMs (mBLMs). Some of these models assume competitive interactions between all metals, while others assume only metals with a similar mode of action (e.g., Na+ or Ca2+ antagonists) will competitively interact. To begin testing these assumptions in the mBLM framework, standard 3-h gill metal binding assays with Ag, Cu, and Ni (primary metals), were performed in vivo on freshwater rainbow trout. Fish were exposed across a range of concentrations encompassing the 96-h LC50 for that metal to characterize uptake kinetics for each of these three primary metals (radiolabelled) in the presence and absence of a secondary metal (Ag, Cd, Cu, Ni, Pb, or Zn; not radiolabelled). We observed a complex series of interactions in binary mixtures that frequently contradicted theoretical expectations. Metals with similar modes of action did competitively interact in some instances, but not others, and when they did compete the competition was not necessarily reciprocal (e.g., Cu inhibited Ag uptake but Ag did not inhibit Cu uptake). We also observed examples of interactions between metals with dissimilar modes of action and several examples of metals stimulating the uptake of other metals. The underlying mechanisms for these unexpected interactions are unclear, but suggest that many of the current assumptions in mBLMs regarding the number and types of metal uptake sites and corresponding metal interactions are not correct. Careful characterization of metal mixture interactions is clearly needed before a reliable mBLM can be developed. © 2016 Elsevier B.V.


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 | Year: 2010

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.


Bouchoud L.,University of Geneva | Sadeghipour F.,University of Geneva | Klingmuller M.,Ecotox | Fonzo-Christe C.,University of Geneva | Bonnabry P.,University of Geneva
Clinical Nutrition | Year: 2010

Background & aims: Two ready-to-use parenteral nutritions (PN) have been developed, for the first days of life of the premature newborn, along with syringes of lipid emulsion with or without vitamins. Long-term physico-chemical stability for storage in wards was assessed. Methods: Physico-chemical stability of PN: visual inspection, particle size, pH, osmolarity measurement, amino acids, glucose, and electrolytes dosages. Physico-chemical stability of lipid emulsion: visual inspection, globule size, peroxide level and vitamins A, E, and C dosages. Stability was studied for 12 weeks on refrigerated (2-8 °C) and room temperature (30 ± 2 °C) samples. Results: No precipitation was detected in any PN. A brown coloration was observed in PN stored for four weeks at room temperature but not in the refrigerator. Concentrations of all the nutrients remained constant over the 12 week-study period. Phase separation of the lipid emulsion occurred after three weeks, but particle size complied with the USP limits for 12 weeks. Peroxide content increased only in the samples without vitamins at room temperature. Vitamins remained stable for one week under refrigeration. Conclusion: The PN did not present a detectable change of the tested properties when refrigerated for 12 weeks. The lipid emulsion with vitamins is stable for one week when refrigerated. © 2010 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism.


Deforest D.K.,Windward | Pargee S.,GEI Consultants | Claytor C.,GEI Consultants | Claytor C.,Copper Development Association Inc | And 2 more authors.
Integrated Environmental Assessment and Management | Year: 2016

We evaluated the use of biokinetic models to predict selenium (Se) bioaccumulation into model food chains after short-term pulses of selenate or selenite into water. Both periphyton- and phytoplankton-based food chains were modeled, with Se trophically transferred to invertebrates and then to fish. Whole-body fish Se concentrations were predicted based on 1) the background waterborne Se concentration, 2) the magnitude of the Se pulse, and 3) the duration of the Se pulse. The models were used to evaluate whether the US Environmental Protection Agency's (USEPA's) existing acute Se criteria and their recently proposed intermittent Se criteria would be protective of a whole-body fish Se tissue-based criterion of 8.1μgg-1 dry wt. Based on a background waterborne Se concentration of 1μgL-1 and pulse durations of 1d and 4d, the Se pulse concentrations predicted to result in a whole-body fish Se concentration of 8.1 μg g-1 dry wt in the most conservative model food chains were 144 and 35μgL-1, respectively, for selenate and 57 and 16μgL-1, respectively, for selenite. These concentrations fall within the range of various acute Se criteria recommended by the USEPA based on direct waterborne toxicity, suggesting that these criteria may not always be protective against bioaccumulation-based toxicity that could occur after short-term pulses. Regarding the USEPA's draft intermittent Se criteria, the biokinetic modeling indicates that they may be overly protective for selenate pulses but potentially underprotective for selenite pulses. Predictions of whole-body fish Se concentrations were highly dependent on whether the food chain was periphyton- or phytoplankton-based, because the latter had much greater Se uptake rate constants. Overall, biokinetic modeling provides an approach for developing acute Se criteria that are protective against bioaccumulation-based toxicity after trophic transfer, and it is also a useful tool for evaluating averaging periods for chronic Se criteria. © 2016 SETAC.


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 | Year: 2013

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.


PubMed | Windward, GEI Consultants and EcoTox
Type: Journal Article | Journal: Integrated environmental assessment and management | Year: 2016

We evaluated the use of biokinetic models to predict selenium (Se) bioaccumulation into model food chains after short-term pulses of selenate or selenite into water. Both periphyton- and phytoplankton-based food chains were modeled, with Se trophically transferred to invertebrates and then to fish. Whole-body fish Se concentrations were predicted based on 1) the background waterborne Se concentration, 2) the magnitude of the Se pulse, and 3) the duration of the Se pulse. The models were used to evaluate whether the US Environmental Protection Agencys (USEPAs) existing acute Se criteria and their recently proposed intermittent Se criteria would be protective of a whole-body fish Se tissue-based criterion of 8.1 g g(-1) dry wt. Based on a background waterborne Se concentration of 1 g L(-1) and pulse durations of 1 d and 4 d, the Se pulse concentrations predicted to result in a whole-body fish Se concentration of 8.1 g g(-1) dry wt in the most conservative model food chains were 144 and 35gL(-1), respectively, for selenate and 57 and 16gL(-1), respectively, for selenite. These concentrations fall within the range of various acute Se criteria recommended by the USEPA based on direct waterborne toxicity, suggesting that these criteria may not always be protective against bioaccumulation-based toxicity that could occur after short-term pulses. Regarding the USEPAs draft intermittent Se criteria, the biokinetic modeling indicates that they may be overly protective for selenate pulses but potentially underprotective for selenite pulses. Predictions of whole-body fish Se concentrations were highly dependent on whether the food chain was periphyton- or phytoplankton-based, because the latter had much greater Se uptake rate constants. Overall, biokinetic modeling provides an approach for developing acute Se criteria that are protective against bioaccumulation-based toxicity after trophic transfer, and it is also a useful tool for evaluating averaging periods for chronic Se criteria.


PubMed | EcoTox and NiPERA
Type: | Journal: Environmental toxicology and chemistry | Year: 2016

Current ecological risk assessment and water quality regulation for nickel (Ni) use mechanistically-based, predictive tools such as Biotic Ligand Models (BLMs). However, despite many detailed studies, the precise mechanism(s) of Ni toxicity to aquatic organisms remains elusive. This uncertainty in the mechanism(s) of action for Ni has led to concern over the use of tools like the BLM in some regulatory settings. To begin addressing this knowledge gap, we used an Adverse Outcome Pathway (AOP) analysis, the first AOP for a metal, to identify multiple potential mechanisms of Ni toxicity and their interactions to freshwater aquatic organisms. The analysis considered potential mechanisms of action based on data from a wide range of organisms in aquatic and terrestrial environments on the premise that Molecular Initiating Events (MIEs) for an essential metal would potentially be conserved across taxa. Through this analysis we identified five potential MIEs by which Ni may exert toxicity on aquatic organisms: disruption of Ca


PubMed | South Eastern Kenya University, McMaster University, University of Nairobi, EcoTox and 6 more.
Type: | Journal: Biology open | Year: 2016

Insect larvae are reported to be a major component of the simple but highly productive trophic web found in Lake Magadi (Kenya, Africa), which is considered to be one of the most extreme aquatic environments on Earth. Previous studies show that fish must display biochemical and physiological adjustments to thrive under the extreme conditions of the lake. However, information for invertebrates is lacking. In the present study, the occurrence of the larval chironomid Tanytarsus minutipalpus is reported in Lake Magadi for the first time. Additionally, changes in larval metabolism and antioxidant defense correlated with diel variations in the extremely hostile environmental conditions of the lake are described. Wide variations in water temperature (20.2-29.3

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